-p
Research Project SOA 78-416
Final Report, September 1979
NUCLEAR ENGINEERIANa
READING ROOM1 MIt
MIT-NE-238
A COMPARATIVE ASSESSMENT OF THE LMFBR AND ADVANCED
CONVERTER FUEL CYCLES WITH QUANTIFICATION OF RELATIVE
DIVERSION RESISTANCE
ia
Principal Investigator
Carolyn D. Heising
44
4
Prepared by
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Cambridge, Massachusetts 02139
A COMPARATIVE ASSESSMENT OF THE LMFBR AND
ADVANCED CONVERTER FUEL CYCLES WITH
QUANTIFICATION OF RELATIVE DIVERSION RESISTANCE
Research Project SOA 78-416
Final Report, September 1979
MIT-NE-238
Prepared by
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Cambridge, Massachusetts 02139
Principal Investigator
Carolyn D. Heising
Research Assistants
I. Saragossi
P. Sharafi
Prepared for
Electric Power Research Institute
3412 Hillview Avenue
Palo Alto, California 94304
EPRI Project Manager
R.F. Williams
Nuclear Power Division
ABSTRACT
Three advanced reactor technologies and their fuel cycles were
compared with respect to their relative economic potential and diversion
These systems include the LWR once-through cycle with and
resistance.
without extended burnup, the LWR and LMFBR on uranium/plutonium recycle
with and without CIVEX reprocessing methods and lastly, advanced converters in
symbiosis with breeders on a denatured thorium cycle.
To
quantify relative diversion resistance, a method based on multi-attribute
decision theory was applied.
Economic potential was measured on the
basis of a simple mills/kWh fuel cycle cost model.
indicate that the LWR-LMFBR (U/Pu)
Preliminary results
cycle can be made as diversion re-
sistant as the LWR once-through cycle if CIVEX-like methods are utilized.
The denatured thorium cycle shows no obvious diversion resistance advantage and exhibits some economic penalty when compared to the other
alternatives.
The economic
calculations show that the choice between
cycles is less likely to be affected by direct economic considerations
than by institutional factors such as fuel cycle implementability on an
industry-wide basis, acceptability to U.S. regulators and the final
prospects for their adoption by U.S. utilities.
i
CONTENTS
Page
I.
II.
III.
SUMMARY................................................ 1
A.
Alternative Nuclear Systems for the U.S .
..........
1
B.
Alternative Fuel Cycle Strategy Economics..........
3
C.
Economic Results....................................
5
D.
Alternative Fuel Cycle Diversion Resistance........
6
E.
Results/Conclusions................................ 10
INTRODUCTION........................................... 13
A.
Purpose of Study................................... 13
B.
Study Analysis Approach............................ 13
C.
Historical Perspective............................. 15
DESCRIPTION OF FUEL CYCLE STRATEGIES................... 19
A.
Basis for Choice of Reference Fuel Cycle Strategies 19
B.
Description of Strategies.......................... 21
C.
IV.
V.
1.
Strategy A: LWR Once-Through with/without
Extended Burnup............................... 21
2.
Strategy B: Plutonium Recycle in LWRs and
Breeders...................................... 23
3.
Strategy C: Denatured Thorium Cycles in
Advanced Converters and Breeders.............. 27
Review of Previous Studies......................... 31
ALTERNATIVE FUEL CYCLE ECONOMICS....................... 39
A.
Busbar Electrical Generating Cost Model............ 39
B.
Key Assumptions/Cost Data.......................... 41
C.
Results and Sensitivity of Analysis................ 43
ALTERNATIVE FUEL CYCLE DIVERSION RESISTANCE ............ 49
A.
Diversion Resistance Quantification Methods........ 49
B.
Application of Diversion Resistance Quantification
Method to Fuel Cycle Strategies.................... 53
C.
Results and Sensitivity of Analysis................ 75
ii
Page
VI.
CONCLUSIONS...........................................
A.
Comparison of Economic Costs and Diversion
Resistance Between Strategies.....................
B.
C.
81
81
Regulatory, Institutional and Industrial
Acceptance Aspects...............................
83
Study Recommendations.............................
90
91
REFERENCES
APPENDICES
Appendix A:
Support Calculations for Electrical
Generating Costs Comparison..............
Appendix B:
Support Calculations for Diversion
Resistance Comparison....................
Appendix C:
A-1
B-1
A Comparison of Available Diversion
Resistance Quantification Methods........
C-1
I
4
iii
ILLUSTRATIONS
Figure
1.
Page
Alternative Nuclear Power Strategies for U.S.
Deployment (1980-2050).......................................
2
2.
Relative Economics of the Alternative Strategies.............
6
3.
Strategy A: Fuel Cycle for 1000 MWe LWR on Once-Through
Uranium Cycle................................................
20
4.
Strategy B: Fuel Cycle for 1000 MWe LWR on U/Pu Recycle......
22
5.
Strategy C: Fuel Cycle for 1000 MWe Liquid Metal Fast
Breeder Reactor..............................................
6.
22
Flow Chart of PUREX Process for Treatment of Low
Enriched Uranium Fuel........................................
24
7.
Modified PUREX Process with Pu-238 Spiking and Np Recycling..
28
8.
Flowsheet for On-Site Facility Based on the AIROX Process....
30
9.
Flow Diagram of the Tin-Nitride Reprocessing Scheme..........
30
10.
Flow Diagram of Strategy C with ACRs Only..................... 32
11.
Flow Diagram of the Symbiotic System with Separate
Processing of Blanket and Core Spent Fuel (T1 )...............
12.
32
THOREX Process T1 : Separate Processing of Blanket and Core
Fuel.........................................................
34
13.
THOREX Process T 2 : Coprocessing of Core and Blanket Fuel.....
34
14.
Chemical Flowsheet for THOREX Process........................
34
15.
Results of Economic Analysis.................................
46
16.
Determination of Development Time............................
60
17.
Isotope Composition of Reactor Grade Plutonium...............
61
C.1
Possible Combinations of Selvaduray's Safeguard Parameter
Sub-Attributes............................................... C-4
I
4
V
TABLES
Page
Table
1.
Economic Assumptions Used in Calculating Total
Electricity Generating Costs of Each Strategy (1975 $).....
2.
3
Assessment of Diversion Resistance Attributes for
Selected Alternative Fuel Cycles...........................
8
3.
Pareto Weights on Diversion Resistance Attributes ..........
10
4.
Pareto Weights on Diversion Resistance Attributes..........
52
5.
Strategy A: LWR Once-Through Diversion Resistance ......... .56
6.
Time Table for Reprocessing Spent Fuel.....................
7.
Strategy B: LWR w/Reprocessing Diversion Resistance ........ 64
8.
Strategy B: LWR w/Reprocessing: Clandestine PUREX Plant
Diversion Resistance.......................................
9.
10.
58
66
Strategy B: LMFBR w/Reprocessing Diversion Resistance ...... 68
Strategy B: LMFBR w/Reprocessing: Clandestine PUREX Plant
Diversion Resistance.......................................
70
11.
Strategy C: Denatured Thorium Cycle Diversion Resistance...
72
12.
Comparison of Strategies...................................
74
13.
Ranking of Alternatives (Non-Crisis Environment) ........... .78
14.
Ranking of Alternatives (Crisis Environment)...............
79
B.1
Strategy A (Non-Crisis Environment): Support Caluclations
for Table 5.............................................. . B-2
B.2
Strategy A (Crisis Environment): Support Calculations for
Table 5....................................................
B-2
B.3
Strategy B (B1): Support Calculations for Table 7...s......B-
B.4
Strategy B (B ): Support Calculations for Table 8..........
*
B.6
Strategy B (B2 ):
Support Calculations for Table 1.........B-12
B.6
Strategy B (B2)
Support Calculations for Table 10 ........
B.7
Strategy C: Support Calculations for Table 11..............
B-20
C.1
Overall Proliferation Risk Index (PRI) for Three LWR Fuel
Cycle Options (Silvennoinen's Method)......................
C-7
C.2
B-10
B-10
B-16
Numerical Assignments Associated with Qualitative Rating
(Heising's Method)......................................... C-9
vi
List of Tables (cont'd.)
...... C-8
C.3
Correspondance Between Method Attributes...............
C.4
Final Resul .3: Rankings Placed on Pathways to Weapons Usable
Material.......................................................
C.5A-G
C-10
Application of Diversion Resistance Methods to Sample
Problem..................................... C-12
I
L
vii
NOMENCLATURE
C=
C~u
C
E
e ap
ef
e.
e
et
fb
F.
fs7=
=
=
=
=
=
=
=
=
=
=
unit price of ith fuel cycle step, 1975 $
cost of plutonium product, $/gm Puf, 1975 $
cost of urnaium, $/lb U 0 , 1975 $
energy produced by batcR, kWh
capital cost contribution to busbar cost, mills/kWh
levelized fuel cycle cost, mills/kWh
initial core contribution to busbar cost, mills/kWh
operating and maintenance cost, mills/kWh
total busbar electricity cost, mills/kWh
debt fraction
discount factor applicable to ith fuel cycle step
equity fraction
= transaction quantity involved in the ith step of the fuel
1
cycle
= effective discount rate
r
rb
= rate of return to bond holders
= rate of return to stock holders
r
= irradiation time of steady state fuel batch, hr
t
= time at which payment of credit for step i will occur, hr
t.
V (x.)
= value function of ith attribute
Vtx x 5) = total value function to proliferator of a diversion route
= ith diversion resistance attribute, i=1-5
x
x
= development time, yrs
= warning period, fraction
x2
=
2log0 of the radioactivity level, R/hr at lm from source
x 31
= sta us of information, dimensionless
x 32
= criticality problem rating, dimensionless
x-33
weapons material guality, dimensionless
x 4=
= monetary cost, 10 1975 %
x5
= ith attribute weighting function, dimensionless
X.
= tax fraction
T
Ms
I.
A.
SUMMARY
Alternative Nuclear Systems for the U.S.
Recent events have emphasized the need for further study into
alternatives to the LWR-LMFBR plutonium based fuel cycle because of
increased concern over nuclear proliferation risk. 1,2
Discussions on
this topic, however, have not been based on thorough analytical studies
of the relative risk associated with the LWR-LMFBR and alternative
nuclear systems.
Risks associated with the once-through cycle, the
alternative to closing the LWR fuel cycle, have not been quantified
nor have the relative risks of denatured thorium alternatives been
compared quantitatively with those of the LMFBR.
Proponents of the
denatured thorium alternative have argued that such a system would alleviate the near-term need for a breeder reactor while simultaneously
3 4
decreasing proliferation risk. ,
However, these arguments have not
been put to the test of a careful, quantitative comparative analysis.
It is the purpose of this study to analyze and compare available nuclear
systems through the application of quantitative risk analysis and costbenefit methods.
Three alternative nuclear systems available for implementation
by the U.S. government have been singled out for comparative analysis
in this work:
(1) the standard light-water reactor (LWR) once-through
fuel cycle operating under either normal operating conditions or on
extended burnup, (2) the LWR and liquid metal fast breeder reactor
(LMFBR) on a U/Pu fuel cycle utilizing either PUREX or CIVEX reprocessing methods, and (3) the LWR combined with advanced converter reactors
(ACRs) operating with or without fast breeder reactors (FBRs) on denatured thorium cycles (Fig. 1).
The CIVEX methods examined in this
study which have recently been proposed5 include for LWR fuel:
(1)
denaturing of plutonium with a Pu-238 spike as outlined by Allied Gulf
Nuclear Services (AGNS),6,7 (2) the Rockwell International AIROX
method,8
(3) coprocessing with actinide partitioning,9 and (4) the
tin nitride pyrometallurgical process.
For breeder
2
Figure 1
Alternative Nuclear Power Strategies for U.S. Deployment
(1980-2050)
Description
Strategy
LWR (once-thru)
with extended burnup up to 60,000 MWO/MT+
permanent storage of spent fuel
A. LWR Once-Thru
without extended burnup
CIVEX
8.
LWR+LMFBR
with U/Pu Recycle
LWR(U/Pu)
CIVEX
(ireprocessing
alternotives)
N
LMFBR(U/Pu)
PUREX
PUREX
LWR w/o Recycle
+ ACR (denatured
C. ttMorium)+ FBR(U/Pu
LWR
(once-thru)
ACR
core, Th blanket)
(reprocessing
alternatives)
HWR (U/Th
P cciei
FBR (U/Pu core,
Th blanket)
ITGRU/Th)
Other Nuclear
- system (e.g.,
fission-fusion
hybrid)
(reprocessing
alternatives)
PUREX/
THOREX
fuel, the Electric Power Research Institute (EPRI) CIVEX scheme,10 which
utilizes Zr and Ru spikes, has been compared with a standard PUREX-based
LMFBR fuel reprocessing method.
In examining the once-through alternative, we consider the effect of
extended burnup on economics, uranium resource utilization and fuel cycle
management.
The Carter Administration has tended
to favor those manage-
ment schemes that can lengthen the uranium resource base for LWRs.
Attention is concentrated on the potential for extending the burnup of
LWR fuel
examining the time frame for widescale introduction in addition
to regulatory and/or institutional problems that might arise from commercial introduction.
Preliminary work by Fard and Driscoll has shown that
the extended burnup alternative could
significantly prolong the uranium
resource base while not introducing major economic penalties.
the material integrity of LWR fuel under such conditions
However,
is only now
being tested,12 and safety-licensing problems might likely eliminate any
advantage of this alternative. 1 3
With respect to the third alternative--the denatured thorium fuel
cycle--the impact of introducing advanced converter reactors was specifically analyzed.
In particular, the high temperature gas reactor (HTGR)
and CANDU heavy water reactor were examined following the "evolutionary"
strategies suggested by Dahlberg, et al. at General Atomic and Feiveson
et al. at Princeton University.
6
3
Table 1
Economic Assumptions Used in Calculating Total Electricity
Generating Costs of Each Strategy (1975 $)
a. Financing Data
= tax traction = 0.5
ts = tb = 0.5
rb = .03. rs = .08
d. Fuel Cycle Cost Data
Thorium:
33 S/kg
Enrichment:
85 S/SWU
Fabrication/Refabrication (S/kgHM):
- LWR
U5-U8
95
277-315
Pu-U
U5-U8-Th
114-187
360-710
U3-U8-Th
b. Capital Cost Data
690 S/kWe
LWR:
1.2 x LWR
HWR:
1.15 x LWR
HTGR:
1.3-1.7 x LWR
LMFBR:
- HTGR
c. Capacity Factors Assumed
HWR All Others
0.75
0.85
Planned CF
0.65
0.75
Actual CF
B.
343-565
733-1335
180-290
U5-U8-Th
U3-U8-Th
Th
U Blanket
Th Blanket
- LMFBR
PUREX
300-450
EPRI CIVEX 330-495
THOREX
(for Blanket)
200
95
95
Reprocessing (S/kgHM):
- LWR
PUREX
200
AIROX
50-60
Coprocessing 200
Pu-238 Spike 210
THOREX
200
-
HTGR (THOREX for U-Pu-Th) 440-990
-
HWR (THOREX for U-Pu-Th) 215
- LMFBR
550-850
Pu-U8 Core
Spent Fuel Shioment (S/kgHM)
- LWR: 13. HTGR: 73.
HWR: 10. LMF8R: 69
Waste Shipping and Disposal
Cost (S/kgHM)
- LWR (U/Pu Recycle): 65,
LWR (once-thru): 185,
HTGR: 85. HWR: 65.
LMFBR: 140
Alternative Fuel Cycle Strategy Economics
The economics of the alternative fuel cycles were analyzed by
calculating the total busbar electrical generating costs for each strategy based on the following simplified model:
+ eic + ef + e
(1) et = e
cap ic
fom
The fuel cycle cost was calculated based on the following formulation:
1000
0
E
(2) ef
f
where (3)
and (4) r
F .=
=
(1+r)
l-T
Z
i=
i i i
(tf /2)-t
T
l-T
(1-T)fb rb + f r
This model assumes that:
investment,
M.CiF.
(2)
(1)
fuel
expenses are treated as a depreciable
the rate of return does not include an allowance for
inflation (constant dollars are assumed),
(3) revenue and depreciation
charges for each batch occur at the middle of the irradiation interval,
and (4) only equilibrium batches are considered.
Reprocessing costs are
estimated based on the cost of modifying a reference PUREX plant to the
specifications required by the particular CIVEX process under investigation (Table 1).
4
Reactor capital costs are estimated as the cost of a typical light
water reactor multiplied by a factor defined as the ratio of the capital
cost of the advanced reactor type divided by the capital cost of a
reference LWR.
The resulting expressions for the total busbar electrical
generating cost as a function of nuclear strategy are:
Strategy A: LWR Once-Through
(5) e
= 21.00 + 0.096 C
t
u
(6) et = 20.78 + 0.087 C
t
u
(normal operation)
(extended burnup)
Strategy B: LWR on U/Pu Recycle
(7) et = 20.92 + 0.074 Cu (PUREX reprocessing)
(8) et = 22.02 +0.080 Cu (AIROX reprocessing)
(9) et = 21.3 + 0.077 Cu (Pu-238 Spike)
LMFBR on U/Pu Recycle
(10) et
=
26.24 + 0.123 CPu (low value, PUREX)
= 33.42 + 0.123 CPu (high value, PUREX)
where CPu is the fissile plutonium value that renders utilities
indifferent between consuming plutonium in LWRs versus LMFBRs:
(11) C
= 0.65 Cu - 37 for low FBR capital cost
= 0.65 Cu - 80 for high FBR capital cost
(12) et = 26.54 + 0.123 CPu (low value, EPRI CIVEX)
= 33.88 + 0.123 CPu (high value, EPRI CIVEX)
Strategy C: ACR on Denatured Thorium
(13) e
= 22.36 + 0.054 C (low value)
t.
u
= 24.0 + 0.054 Cu (high value)
u
6
6
5
C.
Er:onomic Results
On the basis of these relations, busbar electricity costs have been
calculated for the three strategies as a function of U 3 08 cost (Figure 2).
At
From these results, several preliminary observations can be made.
40 $/lb U 3 0 8 , the LWR on either PUREX or coprocessed reprocessing appears
the most aconomically attractive alternative.
The economic penalty asso-
ciated with the AGNS Pu-238 spiking scheme is small and virtually
insignificant; for U 3 0 8 costs above 60 $/lb, this alternative becomes more
economic than the LWR on extended burnup although the trade-off between
the two is highly sensitive to assumptions on reprocessing costs and the
ore savings attainable by reoptimizing the fuel for extended burnup.
The cost penalty associated with the AIROX scheme, mostly due to enrichment penalties, appears significant.
cycXl
The reoptimized once-through LWR
is preferable to the AIROX scheme until very high ore prices are
reached (>180 $/lb U3 0 8).
The range of uncertainty associated with the self- sufficient breeder
economy is quite large.
The median electricity cost we calculate of
30 mills/kWh (1975 $) is higher than the reoptimized once-through LWR
until a uranium price of over 100 $/lb U 3 0 8 is reached.
The breakeven
point is reached at 55 and 145 $/lb respectively for the low and high
values of the LMFBR electricity cost range.
These results are not
significantly affected when the EPRI CIVEX reprocessing scheme is used
In the early period of the deployment of advanced
instead of PUREX.
converters (Strategy C), high costs may be observed because of high costs
of thorium reprocessing and refabrication due to their recent commercial
introduction.
However, experience in time would tend to decrease costs
as economies of scale become realized and the industry matures.
At
40 $/lb U 3 0 8 , the thorium alternative appears to cost only 5% more than
Strategies A or B--a small penalty.
It is also important to note that
Strategy C exhibits the lowest costs as uranium price increases because
of lower U308 consumption rates.
apparent in the
This effect would probably not be
early years of system deployment when the growth of the
system would be greatest because of the large initial inventory of
uranium that would
be required.
6
Figure 2
Relative Ecomomics of the Alternative Strategies
35
30
Al LWR Non Reoptimized
A2 LWR Reoptimized
BI LWR Purex
B2 LWR Coprocessing
B3LWR Airox
B4LWR Pu-238 Spiking
Cl HTGR (Denatured Thorium)
C2HWR (Denatured Thorium)
25
40
80
120
160
Cu($/lb U3 0 8 )
D.
Alternative Fuel
Cycle Diversion Resistance
Fuel cycle diversion resistance was quantified using an assessment
methodology developed at M.I.T. by Dr. I. Papazoglu et al.14
The metho-
dology is based on the principles of multiattribute decision analysis 1 5
wherein a set of indices or attributes which characterize the proliferation resistance of nuclear systems is defined and evaluated for alternative systems.
Diversion resistance is expressed in terms of a set of five attributes that must be considered in a potential diverter's decision to use a
particular technology to derive weapons material.
These attributes are:
(1) the development time, or the time it takes from start to finish to
develop a nuclear explosive using diverted nuclear material, (2) the
warning period, defined as the percentage of the development task left to
)
7
complete at the time of detection by outside agents, (3) the inherent
difficulty of utilizing the technology as a source of nuclear fissile
material
defined further by a breakdown into three sub-attributes--the
radioactivity
level
of the process, the status of scientific and tech-
nical information know about the process by the potential proliferator
and the level of criticality problem associated with the process, (4)
the weapons material quality, defined as the type of nuclear material
diverted (i.e., either weapons or reactor grade plutonium, or enriched
uranium (U-233 or U-235), and lastly, (5) the development cost of the
explosive construction attempt.
Each of these five attributes has been preliminarily assessed for
the three fuel cycle strategies examined in this study.
are given
in Table 2.
These results
To derive a quantitiative indicator of the
relative diversion resistance of each strategy, a.value function for each
attribute has been defined so that a dimensionless numerical indicator
for each route can be calculated.
The numerical indicators for each
attribute are then multiplied by weighting factors (A ) and summed over
the number of attributes to arrive at a single numerical indicator for
each fuel cycle strategy.
Basically, the purpose of the value
function is to provide a
numerical measure of the relative attractiveness of the various proliferation pathways available to the would-be proliferator.
Assuming preferen-
tial independence between attributes (i.e., the proliferator's value
placed on each attribute is independent of the value placed on any other
attribute), the value function is:
5
(14) V(x -x5
. V
=
Because the third attribute (inherent difficulty) is divided into three
sub-attributes, the above expression becomes:
(15) V(x -x5
1
V 1 (x1 ) +
2 V2(x 2 )
3
+
X
j=1
+
3j
V3j (x 3 j
5 V5 (x 5
+ X4 V4 (x 4
8
Table 2
Assessment of Diversion Resistance Attributes foir Selected
Alternative Fuel Cydles
Fuel Cycle Strategy
Strategy A: LWR Once-Thru
- Covert Reprocessing Facility
and Covert Diversion
- Covert Reprocessing Facility
and Overt Diversion
-Overt Indigenous Reprocessing
Facility and Overt Diversion
Status of
Information*
Warning Period (Level of Science.
Development (% of Task to Level of TechTime (Yrs.) be Completed) nology)
Radiation
Level
(R/hr at im
Weapons Development Overall Ranking
from
Material Cost
5
Source)
Criticality Quality (10' S)
I
V
2-4
1
E(2,2)
, 33
2-4
1-3
E(2,2)
33
40-70
E(2,2)
33
1.5-3
Medium Reactor
Grade Pu
Mediim Reactor
Grade Pu
Medium Reactor
Grade Pu
6-16
-.23
6-16
-.24
6-16
-.36
*Status
ofInloanation:
This
attribute
isassessed
asaseparate
ranking
ofbWh
thelevel
ofscience
andlevel
ottechnology
known
about
aparticular
technology.
Thelevels
are:I. known.
2 readily
available
and3=unknown orclassified.
Theletters refer
tooneoftheninepossible
orderings
ofthese
levels:
A(1.1)= bestknown.
1(3.3)
= least
known.
Fuel Cycle Strategy
Strategy 8: LWR and/or LMFBR
on U/Pu Recycle
Status of
Information
Warning Period (Level of Science.
Development (% of Task to Level of TechTime (Yrs.) be Completed) nology)
Material
Diversion
Overt Covert
- 81: LWR (U/Pu) without LMFBR
-PUREX Commercial Plant
.5 5
-Coprocessing Com. Plant
1 5
-Pu-238 Spike Com. Plant
100 100
-AIROX Commercial Plant
1.5 5
-Tin Nitride (Pyrometalgy.)
1.5 5
- 82: LWR + LMFBR (U/Pu)
-PUREX Commercial Plant
-EPRI-CIVEX Com.
Plant
Fuel Cycle Strategy
Strategy C: Denatured Thorium
Advanced Coverters and
Fast Breeders (U/Pu/Th)
-Diversion from LWR Spent Fuel
Ponds with covirt PUREX Plant
Built Indigenously with Commercial THOREX Plant inCountry
- THOREX Commerbal Plant with
Separate Processing of F8
Blanket and Core (T1)
-THOREX Commercial Plant with
Coprocessing of Core and
Blanket (T2)
- Build Clandestine THOREX Plant
to Process ACR or FBR Fuel
.5 5
1-1.5 5
Overt Covert
(Independentof overt or covert operation)
1
1-3
100
1-3
1-3
A (1,1)
8 (1.2)
I (3.3)
E(2.2)
E(2.2)
10-4-10-6
.66
104-10-6
6.6
.66
Medium
Low
Medium
Low
Low
R.Gr.Pu
R.Gr.Pu
R.Gr.Pu
R.Gr.Pu
R.Gr.Pu
2
3.5-6
1000
5.5-8
5.5-8
1
40-70
1
1
A (1.1)
A (1,1)
10-4-10-6
165
Medium
Medium
R.Gr.Pu
R.Gr.Pu
2
4-12
Material
Diversion
Overt Covert Overt Covert
1 5
1-3
1
1
1
1.1 1.1 55-77
T1
1
4-6
(Independent of overt or covert operation)
8(1,2)
33
Medium R.Gr.Pu
8 (1,2)
E(2,2)
T1
8(1.2)
-.09 -.18
-- 1l -.19
-1.0 -1.0
-. 11 -.23
-. Is -.23
-.09 -.18
29 -.22
-
Radiation
Level
(R/hr at Im
Weapons Development Overall Ranking
from
Material Cost
5
Source)
Criticality Quality (10' $)
1
.V
0
-
T1
1-1.5
Overt Covert
1
50
100
90
90
Status of
Information
Warning Period (Level of Science,
Development (% of Task to Level of TechTime (Yrs.) be Completed) nology)
.5 1
Radiation
Level
(R/hr atlm
Weapons Development Overall Ranking
from
Material Cost
5
Source)
Criticality Quality (10* S)
I XV
0
0
Medium High Enriched
U-233
Medium R.Gr.Pu
Medium High Enriched
U-233
4-12
Overt Covert
-.15 -.21
2
-.08 -.10
4-12
-.31 -.i6
3.5-12
T1
.L -. 9
-Attributes
assessed
assuming
a commercial
THOREX
Plantoperatngin NWSat timeofconstruction
of clanoestine
plant of typeTt or T2 matenaldiversion is assumed
to takepace covertly
-
9
where the value functions for each of the five attributes are:
development time:
1,
e
(16) V (x)
(16 1.83
.49 non-crisis,
crisis
=1
warning period:
(17) V2 (x2) = eYX 2 - 1, y
6.93
=
radioactivity level:
(18)
x 31
0
V31 (x31
0
1
-.02
2
3
-.16
4
-5
5
-.84
6
-.96
-1
status of information (x3 2 referring to levels denoted as
A, B, C...I):
32
(19)
x32
Al
V32 (X32
0
D
-01
B
-.05
E
-.16
G
C
H
-.84
-.67
-.37
criticality problems (x3 3 either "High,"
(20)
V 33("Low") = 0, V3 3 ("Med")
= -. 5,
F
I
-.95
"Medium,"
-.99
or "Low"):
V 3 3 ("High") = -l
weapons material quality (x4 refers to type of material):
(21) V4 (r.g.Pu) = -1,
V 4 (H.E.U-233)
V4 (w.g-.Pu) = -. 5,
= -.25 and V4 (H.E.U-235)
=
0
and finally, for monetary development cost:
(22) V 5( 5
= -ax
S;
5
a = 2.6 x 10
a = 10
Weighting functions (A)
-5
,
-4, S = 1.27 non-crisis
S = 1.9 crisis
derived from interviews with selected experts
utilizing a standard Delphi technique were assessed for two hypothesized
divertor decision environments--non-crisis
and crisis (Table 3).
10
Table 3
Pareto Weights on Diversion Resistance Attributes
Weighting
Function
Non-Crisis
Environment
Development Time
A1
.13
.31
Warning Period
A2
.15
.07
Status of Information
x31
.38
.37
Radiation Level
A3 2
.16
.16
Criticality Problems
x33
.04
.04
Weapons Material Quality
A4
.03
.01
Development Cost
A5
.11
.04
Attribute
Combining these weighting functions with the value
Crisis
Environment
functions described
above, the final numerical indicators (E A V ) were calculated as shown
ii
in Table 2.
Note that
on a scale that varies form -1 to 0
the more
negative the final indicator, the more diversion resistant the technology.
Thus, a ranking of -.08 would indicate a very low diversion resistance
while a ranking of -.8 a very high degree of diversion resistance.
E.
Results/Conclusions
The assessment shows that the LWR-LMFBR (U/Pu) fuel cycle (Strategy
B)
can apparently be made as diversion resistant as either the
LWR on the once-through cycle or any combination of advanced converters
operating on a denatured thorium cycle.
The final quantitative rankings
indicate that through use of CIVEX-like reprocessing methods such as
Pu-238 spiking, the diversion resistance of the plutonium-based cycles
can be increased to at least the resistance level of the once-through
cycle.
Moreover, it is evident that unless coprocessing or some other
equivalent technology is used to increase the diversion resistance of the
THOREX process, the denatured thorium alternative can be less diversion
resistant than either the LWR once-through (Strategy A) or the LWR-LMFBR
(U/Pu) case (Strategy B).
From the preliminary results of this study, it is suggested that the
LWR-LMFBR (U/Pu) cycle can be made at least as diversion resistant as
either the once-through cycle or any combination of advanced converters
4
11
on denatured thorium cycles if CIVEX-like processes are utilized.
This
may be achievable, on the basis of our economic results, without substantially affecting the relative economic compe-titiveness of the mixed oxide
fuel cycle.
We also conclude that the AIROX method is probably not
attractive because of its increased costliness and inability to increase
diversion resistance vis-a-vis other available CIVEX-like reprocessing
methods.
Our preliminary study of the institutional problems indicates
that the choice between alternative nuclear systems is less likely to be
influenced by direct economic considerations (i.e., the total cost of
electricity to the American consumer) than by institutional factors such
as fuel cycle implementability on an industry-wide basis, acceptability
to U.S. regulators and the final prospects for fuel cycle adoption by
U.S. utilities.
4
a
13
II. INTRODUCTION
A.
Purpose of Study
The purpose of this study is to quantify the risk-cost-benefits of
the LWR-LMFBR fuel cycle in comparison with alternative advanced converter
fuel cycles that have been suggested for future use.
Emphasis is placed
on U.S. nuclear planning alternatives but international implications of
fuel cycle decisions are also examined.
Risks that are quantified and/or
compared include: (1) health, environmental and safety, (2) nuclear
theft and sabotage (subnational diversion) risks, (3) nuclear proliferation (national diversion) risks, and (4) institutional licensing - regulatory risks.
Primary effort has been directed toward the quantification
of diversion resistance between fuel cycles in the context of alternative
routes to weapons material attainment.
B.
Study Analysis Approach
This study employs quantitative methods to estimate both the econo-
mic costs and relative diversion resistance of three alternative nuclear
power strategies projected for U.S. deployment over the next few decades
(1980 - 2050).
Particular emphasis is placed on the LWR-LMFBR plutonium
based fuel cycle, which had been the preferred strategy of choice until
economic uncertainties and concern over proliferation brought the strategy under re-consideration.
In addition to diversion resistance, dis-
cussion is made of the potential differences in other technological risks
such as health-environmental-safety
and subnational diversion.
Also,
a
contrast of institutional problems between fuel cycle alternatives is
made.
However,
the major emphasis in
this study has been directed toward
the quantification of the relative diversion resistance between fuel cycle
alternatives.
Work under the project has been divided into three tasks, which are
covered in this report as follows:
TASK I (Primary)
Quantification of the risk related costs of alternative nuclear
fuel cycles, particularly the proliferation-diversion resistance
of the LWR-LMFBR plutonium based cycle versus alternative
advanced converters on denatured thorium (or uranium) fuel
cycles (Section V, VI, Appendix B).
14
TASK II
Quantification of economic benefits of a breeder based
nuclear economy in comparison with proposed alternative
advanced converter nuclear economics (Section IV, Appendix A).
TASK III
Development of analytic framework for comparison of
alternative advanced nuclear fuel cycles (potentially
applicable to NASAP and/or INFCE studies) (Section VI).
In performing these tasks, appropriate methods have been developed and
extended to quantify the relative electrical busbar costs and diversion resistance of the three nuclear fuel cycles under consideration.
Also, a review of recent studies that pertain both to analysis of
alternate fuel cycles and to diversion resistance quantification has
been made (Section IID and Appendix B).
In approaching Task I, a multiattribute decision theory model
developed at MIT was utilized because it was found to be the most comprehensive method currently available (see Appendix C for a review of
existing diversion resistance quantification methods).
Institutional
problems dealing with the implementability of each fuel cycle was discussed in terms of lead times for development and commercial demonstration in the United States.
For Task II, electrical generating
costs were determined to be the single most critical attribute affecting U.S.
electric utility
choice betweencompeting nuclear systems.
Electricity cost, as generated by nuclear units, depends strongly
on the cost and scarcity of uranium resources.
However, capital
costs for reactors not presently commercialized in the U.S. are also
critical determinants of a strategy's relative economic
attractiveness.
The approach we have taken to analyze Tasks I and
II constitutes the analytic framework we suggest for comparison of
alternative advanced nuclear fuel cycles (Task III); we believe that
a similar approach should be taken within the NASAP and INFCE studies.
Historical background to the NASAP/INFCE studies is given in Section
IIC of this report.
4
15
C.
Historical Perspective
To some, especially those engaged in the nuclear industry, the
emergence of the nuclear proliferation issue has occurred at a most
inopportune time.
Already beleaguered by environmental, health and
safety concerns coupled to the less tangible risks of theft and
sabotage, the concern over proliferation has seemed only an additional
burden to the industry.
With the events at Three Mile Island, the
public questions the efficacy of nuclear power to an even greater
extent than before.
But even before TNT, events had led nuclear
spokesman Alvin Weinberg to observe that "nuclear energy is in
trouble".17
This observation has been reinforced by events at TMI
even while concerns over proliferation have only seemed to subside
in the wake of public reaction to the accident.
In the midst of this
unfortunate historical period for nuclear power, it is important that
those in positions to affect energy policy strive for a balanced view
in deciding the future course of nuclear power.
Concern over reactor
safety must be balanced not only against other risks such as proliferation, but also against the economic impact of policy decisions.
When discussing alternative fuel cycles from the viewpoint of proliferation risk minimization, it is therefore imperative that both
safety and economic differences be simultaneously considered so that
conclusions can be drawn on a balanced basis.
The emergence of the proliferation issue occurred most recently
after India's successful 1974 detonation of a nuclear explosive using
material illegally diverted from a Canadian imported research reactor.
As a result, the international safeguards system was laid open to review.
American pressure for change increased further after 1976 when
West Germany, Brazil, France, Pakistan and South Korea began to conclude commercial agreements for the international sale of reprocessing
technology.
However, proliferation has been a continual concern of
the arms control - political science community since the advent of
nuclear explosivesduring World War II.
In the U.S., the history of civilian nuclear power began in 1946
with the formation of the Atomic Energy Act (Acheson-Lilienthal)
authorizing the government's key supervisory role in nuclear power
16
commercial development.
This early act underlies current Carter
Administration positions on the strict control of nuclear materials,
4
then of interest because of the arms race with the U.S.S.R. and now
of concern because of the rise of worldwide terrorism and the fear of
nuclear proliferation.
In 1954, a major revision of the Atomic Energy Act occurred with
4
President Eisenhower's change in policy toward commercial nuclear
power expressed in his famous "Atoms for Peace" speech delivered at
the United Nations.
This policy helped stimulate the world's desire
for nuclear research and commercial reactors which were sold at highly
subsidized prices.
Congress loosened controls over nuclear materials
to promote the private nuclear sector and the International Atomic
Energy Agency (IAEA) was organized to safeguard and assist the growing
worldwide nuclear industry.
During the 1960's, this policy was
generally continued.
Then, in the 1970's, a resurgence of interest took place in
safeguards and proliferation in reactions to increase in terrorist
acts around the world, the findings of several investigations that
existing safeguards were inadequate, the Indian detonation of 1974
and public concern over the viability of nuclear power as an acceptable energy source.
In response to these events, the government re-
organized several agencies and passed stringent regulations on the
export of sensitive technologies and the handling and transportation
of nuclear materials, the most recent being the Nuclear Non-Proliferation
Act of 1978 (NNPA).
Also, on April 20, 1977, President Carter deferred
indefinitely the commercialization of nuclear fuel reprocessing and
the plutonium-based breeder reactor.
He also called for and created
the International Nuclear Fuel Cycle Evaluation
INFCE) and the U.S,
government's Nonproliferation Alternative Systems Assessment Program
(NASAP) which were to study alternative nuclear technologies and
institutional arrangements that might reduce the connection between
civilian nuclear technology and the risk of proliferation.
These
studies were to be completed by 1980 in order to better achieve international concensus on the future of nuclear power.
The study that is
covered in this report explores three possible strategies the US. could
4
17
adopt with respect to both their relative economics and diversion
resistance.
This study therefore relates directly to the stated
goals of the NASAP and INFCE projects.
4
19
III.
A.
DESCRIPTION OF FUEL CYCLE STRATEGIES
Basis for Choice of Reference Fuel Cycle Strategies
Three advanced nuclear power strategies are examined in this study
that could be implemented in the United States between 1980 through 2050:
Strategy
Description
A
LWR once-through with or without extended burnup
B
LWR with U/Pu recycle + LMFBR with U/Pu recycle
C
LWR once-through + advanced converter (HWR or HTGR)
on denatured thorium cycle + FBR with thorium blanket
As another permutation of these strategies, we also examined the effect
of civilian extraction (CIVEX) fuel processing techniques on the relative
diversion resistance and economics of the overall strategy, particularly
for Strategy B.
The following reprocessing methods were examined:
LWR
LIMFBR/Other FBR
1.
PUREX
1.
PUREX
2.
Coprocessing + Actinide Partioning
2.
EPRI-CIVEX: Zr+Ru Spikes
3.
Pu-238 Spiking
4.
AIROX
5.
Pyrometallurgy (Tin Nitride)
These three strategies were chosen based on the findings of previous
studies and based on current government policy regarding the future of
advanced nuclear systems in the United States (Part C of this Section
details the results of previous studies).
The use of thorium in light
water reactors was not examined here because of findings by other investigators30,34,37 that such use was not economic relative to uranium cycles
and that thorium is best used in advanced convertor reactors.
For the once-through alternative strategy A, the effect of extended
burnup (up to 60,000 MWd/MTHM) on economics, uranium resource utilization
and fuel management have been examined.
The current administration tends
to favor those management schemes that can lengthen the resource base for
LWRs on the once-through cycle while maintaining competitive fuel cycle
economics vis-a-vis coal fired plants.
Attention has been directed in
this study on the time frame of widescale introduction that is likely for
Figure 3
Strategy A:
URANIUM
MINES/MILLS
Fuel Cycle for 1.000 MWe LWR on Once-Through Uranium Cycle
[-A F-A F]
ENRICHMENT
PLANT
FABRICATION
PLANT
OUTSIDE
NWS
CD
FUEL
ASSEMBLIES
27,271 kg U
3.3 w/o U235
F-1
a
LIGHT WATER REACTOR
1000 MWe
THERMAL EFF.: 0.325
EXPOSURE TIME :I1OO DAY
BURNUP:33,000 MWD / MT
CAPACITY FACTOR-: 0.80
IRRADIATED
SSPENT
FUEL
FUEL
STORAGE
150 DAYS
COOLED
SPENT FUEL
INSIDE
NWS
21
this strategy and any regulatory or institutional problems that might
influence timing (see Section VIB).
For Strategy B, we emphasize that LWRs on U/Pu recycle can also be
optimized for maximum resource efficiency and/or fuel cycle cost minimization.
This point has not been widely recognized among some policy-
makers, but is certainly well know among experts in the fuel management
area.26
With respect to Strategy C, this study specifically analyzes the
impact of Advanced Converter Reactor (ACR) introduction on the U.S.
economy and on diversion resistance.
In particular, the study focuses on
the denatured thorium schemes proposed by General Atomic (HTGR and GCFR
utilization)
strategies
4
and Feiveson, Von Hippel and Williams
3
as
alternative to the plutonium based breeder.
chosen for comparison with the once-through alternative
evolutionary
This strategy is
(Strategy A)
and plutonium recycle alternative (Strategy B) because of the recent
federal government interest in this alternative (Strategy C) and because
of the lack of any quantitative comparison to date of the relative economics and diversion resistance of this strategy.
B.
Description of Strategies
1.
Strategy A: LWR Once-Through with/without Extended Burnup
Strategy A assumes light water reactors on a uranium once-through
cycle with fuel either -exposed to an average of 33,000 MWD/MT or on
extended burnup up to 60,000 MWD/MT.
A description of the fuel cycle for
this strategy is given in Figure
For the purposes of the diversion
3.
resistance assessment (Section V of this report), it is assumed that only
reactors are allowed within the boundaries of a non-weapons state (NWS) with
fresh fuel supplied from outside the country and spent fuel stored inside
the country for periods of ten years or more.
The impact of a policy
wherein long-cooled spent fuel is returned to the weapons states
to a multinational center located outside the NWS
possibly
is also examined.
4
22
Figure 4
Figure 5
Strategy B:
Strategy B:
and U Blanket
Fuel Cycle for 1000 MWe LWR on U/Pu Recycle16
Fuel Cycle for 1000MWe Liquid Metal Fast Breeder Reactor; U/Pu Core
16
I
I
I
RECOVERED URANIUM
I
I
I
23
2.
Strategy B: Plutonium Recycle in LWRs and Breeders
Strategy B is composed both of light water reactors and liquid metal
fast breeder reactors allowing reprocessing of spent fuel and U/Pu
recycle.
This is the strategy originally expected to be implemented in
the United States and which is being implemented in France and the Soviet
Union.
The following figure describes this strategy:
IVEX
CIVEX
LWR (U/PU)
Reprocessing
Alternatives
LMFBR (U/Pu)
Reprocessing
Alternatives
PUREX
PUREX
Included in this strategy are various reprocessing alternatives that
might decrease diversion resistance below the level inherent to the traditional PUREX process.
Of course, it is not clear today which repro-
cessing technology will be adopted, if any, in future civilian U.S.
operations.
For the purposes of
assessing diversion resistance, it is assumed
that Strategy B can be divided into two sub-systems.
that Non-Weapons States
First, it is assumed
(NWS) are restricted to operating LWRs but are
allowed to operate commercial reprocessors to process fuel from their
LWRs.
In this system (B*), breeders are assumed to be operated outside
the NWS or not at all.
For the second sub-system (B**), both LWRs and
LHFBRs are allowed to be operated inside NWSs along with their corresponding fuel processing facilities.
The fuel cycle flow diagram for an
LWR or U/Pu recycle is given in Figure 4
and for the LMFBR in Figure 5.
For the case of LWR fuel reprocessing, the following processes have
been considered:
(1) PUREX, (2) coprocessing + actinide partitioning, (3)
Pu-23 8 spiking (denatured plutonium), (4) AIROX, and (5) the tin nitride
pyrometallurgical process.
These processes were selected because of their
contrasting differences that presumably impact on the diversion resistance
of LWR spent fuel reprocessing.
are examined:
For the LWFBR, two reprocessing methods
(1) PUREX and (2) EPRI-CIVEX: Zr+Ru Spiking.
These are the
only two processes which recently have been suggested for LMFBR spent fuel
processing.
Each are now described.
4
24
I
Figure 6
Flow Chart of PUREX Process for Treatment of Low Enriched
Uranium Fuel
I
FEED SOLUTION
FROM DISSOLVER
HNO 3
REDUCING
WATER
SCRUB SOLUTION
WATER
0
4
(FISSION PRODUCTS)
4
I
I
25
The PUREX process is an aqueous solvent extraction technique that was
developed in the late 1940's; it is the only commercially available reprocessing technique today.
Figure 6.
A flow chart of the PUREX process is given in
A solution of 30 vol.%
tributylphosphate in a kerosene-type
diluent is employed as the solvent with nitric acid as the salting agent.
A separation is accomplished because of the extraction of uranyl nitrate
and plutonium (IV) nitrate and the relative inextractability of fission
products and plutonium (III) nitrate.
By changing the oxidation state of
plutonium, it can be separated from uranium.
The heart of the PUREX
process consists of two solvent extraction cycles for gross decontamination of each product: one cycle providing decontamination and partitioning
of uranium and plutonium and the second providing further decontamination
of separated products.
Coprocessing is a PUREX based solvent extraction concept involving
recovery of all the actinides in the spent fuel as a product group.
It
has been shown that this can be accomplished by a simple modification of
the PUREX process.
The recovered actinide product group can be reconsti-
tuted as a fuel for recycle in LWRs
(LMFBRs)
or liquid-metal fast breeder reactors
either by addition of moderately enriched uranium for the LWR
or by controlled partial partitioning of uranium in the L4FBR.
Potential
for proliferation can be reduced for substantial diversion since plutonium
is not separated from its actinide homologs nor is the recovered actinide
fuel fully decontaminated from the fission products.
The Pu-238 spiking concept has been suggested by AGNS and deVolpi
at ANL for conventional LWR fuel design, including the option to recycle
plutonium in mixed-oxide (MOX) fuels.
In this concept, the reactor is
fueled in such a way that the plutonium produced during reactor operation
contains an unusually high percentage of the isotope
as compared to 1%).
Pu-238 (about 5%
Because of the high heat generation rate of Pu-238,
elevated material temperatures would result when significant concentrations
of Pu-238 are present.
The high temperature encountered during the fabri-
cation, assembly, and storage of a nuclear device would be expected to
severely complicate weapons productions because the high explosive surrounding the fissile trigger would probably melt.
Therefore, the spiking
of Pu with the isotope Pu-238 to a concentration greater than 5% by weight
26
would make reactor generated plutonium considerably less attractive for
weapons purposes.
Unlike other spikes that are being considered to com-
plicate the diversion of reactor plutonium (e.g., the introduction of a
gamma emitting spike such as Co-60), the heat spike (i.e., Pu-238)
cannot be removed by chemical techniques.
Also, according to deVolpi,
methods by which to separate the isotopes in a mixture such as would be
encountered are not well known or available:
"Separation of the fissile fraction from the Pu-23 8 , Pu-239,
Pu-240, Pu-241, Pu-242 chain would be very difficult with
existing technology... .The relative irreversability of the
plutonium chain offers a marked improvement over a relatively
reversible diluent such as U-238 in U-233 or even U-235 when
starting with a few percent enrichment."
A schematic of the modified PUREX process that the Pu-238 spiking scheme
requires is shown in Figure
7. Note that Np would be separated out and
sent to the fuel fabricator as a precursor of Pu-238
formed during
reactor operation as follows:
I Pu-238
Np-237
(2 days)
Np-2381
(7 days)
U-235
---
n--
U-236
U-237
n
U-238,
n
(n, 2n)
AIROX (Atomics International Reduction Oxidation) is a relatively
new technique that refers to a reprocessing cycle using thermal chemical
reactions to cause chemical compound changes.
An important aspect from a
diversion resistance perspective is that it employs both gaseous and
solid materials--no liquids are used.
AIROX was initially developed for
LWR's in the early 1960's and has gone through several cycles of demonstration, including fuel fabrication and irradiation.
The cyclic AIROX
4
process thermally converts UO 2 to U3 08 with air termperature at 4000 C and
reduces the U308 to UO2 with hydrogen in nitrogen at 6000 C.
Oxidation
produces an " 30% volume increase that stresses the compound sufficiently
to cause cladding rupture and a breakup of the UO 2 structure that partially
pulverizes the fuel material.
4
This pulverization permits release of en-
I
27
trapped volatile fission gases, commutes
to oxide fuel and provides
gaseous oxygen access to the unreacted fuel.
Ultimately, a particle size
distribution is generated that is suitable for pelletization and refabrication.
A schematic of the process is given in Figure 8.
The tin-nitride process, chosen as an example of a pryometallurgical
process, calls for dissolving the spent nuclear fuel in liquid tin followed
by selective nitriding of the uranium.
The fission products would either
form nitrides or intermetallics that float, whereas the uranium nitrade
precipitates would sink along with the plutonium and other actinide nitrides.
The uranium is recovered as a nitride which may be either reduced
to its metallic state or be converted to oxide, carbide, or halide for
enrichment, as the
given in
3.
case may dictate.
A schematic of the process is
Figure 9.
Strategy C:
Denatured Thorium Cycles in Advanced Converters and
Breeders
Strategy C is based upon the utilization of thorium fuel.
It is
composed of an LWR without recycle in the once-through cycle, an advanced
convertor reactor (ACR) operating on a denatured thorium cycle, and
finally a fast breeder reactor (FBR) utilizing an U/Pu core and thorium
blanket.
Deployment of thorium cycles, development of commercial scale
thorium reprocessing plants and thorium breeders have not been commercially established.
The proliferation resistance of thorium reprocessing
techniques has also not been demonstrated.
In this strategy, FBRs act as a fuel factory in addition to a power
source by supplying the fuel requirements of ACRs.
The symbiotic system
is more efficient in its usage of uranium in the long run than are ACRs
alone.
FBRs are introduced because as uranium cost increase they become
more competitive and cheaper to run than ACRs.
FBRs might be introduced
at the same time as ACRs or after ACRs have been deployed alone.
Figure
10 shows the flow diagram of Strategy C when only ACRs are deployed.
flow diagram of the symbiotic system is shown in Figure 11.
The
0
28
Figure 7
Modified PUREX Process with Pu-238 Spiking and Np Recycling 6'
7
I
I
ESS
U3 08
50% U-236
TO TAILS
4
MAKE-UP
U30s
15% Np
TO WASTE
I
29
There is a tradeoff between the rate at which the symbiotic system
can grow and the ratio of dispersed ACRs to confined U-233 generating
breeders.
Indeed, increasing replacements of fertile U-238 by fertile
Th-232 in FBRs leads to: (1) an increase in the amount of U-233 available
for ACRs and therefore an increase in the
ACR
ratio, and (2) a decrease in
the amount of Pu produced and therefore a decrease in the growth rate of
FBRs
which are the factories of U-233.
Except for relatively small
growth rates of demand for nuclear energy, and given that a relatively
ACR
large A
ratio is desirable (otherwise the purpose of the symbiotic
system which is to confine
fresh Pu fuels to a few sites
U-235 fueled ACRs or LWRs will be required with
is defeated),
the symbiotic system.
-
With regard to THOREX reprocessing methods for both ACR and LMFBR
fuel, both conventional THOREX and non-conventional, conceptual CIVEXlike THOREX processes have been examined.*
We define two separate THOREX processes for use with the FBR blanket
and core spent fuel:
T :
Separate Processing of Blanket and Core Fuel --
In this concept,
the core fuel consisting of denatured U-233 and plutonium
produced during fuel irradiation in the reactor
would be
coprocessed such that U/Pu would not be found in separated
streams
while the blanket fuel containing thorium and the
bred U-233 would pass through a THOREX processing stage to
separate out a pure U-233 stream (Figure 12), and
T2:
not
Coprocessipng of Core and Blanket Fuel -- This method would
produce a pure U-233 stream, thus increasing diversion resistance
but impacting on ACR/FBR fuel fabrication economics.
In this
concept, thorium would be separated out in the first stage
extractor.
Coprocessing of the remaining fuel would separate
the usable products (U-233, U-238, Pu) from the fission product
wastes.
The coprocessed mixture would then be sent to a
refabrication plant for both ACR and FBR fuels (Figure 13).
*
The only attempt at co-processing uranium-thorium appears to be work
being donducted at the High Temperature Iaterials Laboratory at San
Jose State University. The wark is a modification of the tin nitride
process. It is in a very early stage and there is insufficient information available at this time to be able to make realistic economic
cost estimates.
30
Flowsheet for On-Site Facility Based on the AIROX Process.
Figure 8
U
PRODUCTS
CLADDING
4
GASEOUS
FISSION
PRODUCTS
I
U-Pu-FISSION PRODUCTS
(POWDER)
4
Flow Diagram of the Tin-Nitride Reprocessing Scheme
Figure 9
I
[METALLIC-URANIUM
EOREA.COR
F CLUEL
SPENT OXIDE, CARBIOE
R NITRIDE FUELS
ANO CLADOING
STOICHIOPAETRic
'CARBON TO
REDUCE OXIDE
LT .Uj
SPENT FUEL (U+ FP)
QvOLA
IPT
ILE
INERT ATMOS__
|
R"
U(WI + NON-VOLATILE FP
G
, . .-
a
(SOLIDS)
FP TRAP
STAGE-A
PREMELT
550*C
ITROGEN
TiN SOLUTION14
1350*C
LOOPTO REMOVEFP FRCM SOLVENT
METAL (DISTILLATION 8/OR HIGH
PRESSURE NITRIDE PRECIPITATION)
4
UN
SOLID FP 8 CLADDING
-.- JN (TO REAC1ORIF DESIRED)
{
(N2 OFF)
VACUUM
Tim
STAGE C
INTERMETALLIC OF URANIUM AND OTHER ACTINIOES
OXIOIZE SOLUT ICN
TO FORM OXIOE
DISTILL OFF TIN OR ACO Mg TO
REDUCE URANIUM SOLUSILITY
U METAL
.
U (REACT TO FORM UFO
OR CARBIDE)
31
The THOREX process chemical flowsheet is given in Figure 14.
Note that in the traditional process, U-233 is separated out in a pure
stream.
Unless this stream is denatured with U-238 and/or other isotopes
of uranium, the existence of the pure U-233 stream could
constitute as
a diversion risk as does the existence of the purified reactor-
much
grade plutonium stream in the PUREX process.
The THOREX process is a
solvent extraction process which employs tri-n-butyl phosphate (TBP) as
the extractant, nitric acid catalyzed with fluoride ion as the thoriumdissolution agent with either aluminum nitrate or nitric acid as the
salting agent.
The U-233 product is isolated by ion exchange.
Thorium
is less extractable than uranium and is recovered in column 1B by contacting the organic product from the previous column with dilute nitric
acid.
C.
The thorium product is concentrated by evaporation.
Review of Previous Studies
A review of the literature was undertaken to determine previous
study results related to each of the three nuclear power strategies
examined in this report.
1.
LWR Once-Through (With/Without Extended Burnup)
11 1 7
'
The work of Driscoll, Abbaspour and Fard at MIT was reviewed.
Strategy A:
In that work, the fuel cycle economics of improved uranium utilization
in LWRs were estimated.
Conclusions were that:
(1) increasing core burn-
up was economically advantageous so long as the number of staggered core
batches was increased concurrently, (2) the thorium fuel cycle in LWRs was
not found to be economically competitive, (3) steel clads could- be useful
in very dry cores where its superior properties might be advantageous, and
(4)
increasing the scarcity related escalation rate of ore price or the
absolute cost of ore does not alter the mnajor conclusions.
In the work of A. Roberts at EPRI 12,13 demonstration of fuel performance at high burnup was reviewed.
for LWR fuel at high burnup:
He points out three major problems
(1) internal pressure buildup due to release
of fission products (relates to LOCA effects),
(2) zircaloy waterside
corrosion , and (3) zircaloy susceptability to attack by fission products
generated by fissioning oxide fuel requiring a support barrier be placed
6
32
6
Figure 10
Flow Diagram of Strategy C With ACRe Only
I
I
I
IRRADIATED
THORIUM
Figure 11
Flow Diagram of the Symbiotic System with Separate
STORED
W.G. PLUTONIUM
4
Processing of Blanket and Core Spent Fuel (T )*
I
33
between the UO 2 and the zircaloy inner surface (either copper plated on
the inner diameter surface or zirconium co-extruded with the zircaloy).
To modify current fuel designs to minimize these three effects, a long
and expensive demonstration program is likely.
Other work reviewed included Golay, Saragossi and Sefcik's work at
MITl8,19 and work done by the DOE on estimating the charge for spent fuel
storage and disposal services.
20
Discussion of the conclusions that
can be drawn on the basis of this work is found in Section IV of this
report.
Also, current DOE policy on the extended burnup alternative
was reviewed.21,22
2.
Strategy B: LWR and/or LMFBR on U/Pu Recycle With/Without CIVEX
Reprocessing Methods
For this strategy, a review of the literature concerning civilian
extraction (CIVEX) processes was conducted.*
The work by Pobereskin et
al. on coprocessing was used to establish cost estimates on this process,
9
the work by Levenson and Zebroski for the LMFBR EPRI-CIVEX process,10 and
the work by Asquith et al. to establish AIROX estimates.
Information on
the denaturing of plutonium concept was derived from work done at AGNS7
and by de Volpi at Argonne National Laboratory. 6
Other work that has been done in this area and was used as background
material included the paper representing DOE positions by Saul Stranch
on alternatives to plutonium separation,
25
Eschbach on fuel
cycles with reduced proliferation characteristics
26 and the work by the
Atomic Industrial Forum on technical deterrents to proliferation.5
Experi-
mental work on proving the validity of CIVEX-like processes is being
carried out in Italy by Moccia et. al.28
Work on the relative economics
of fuel cycle strategies is being done by Manne and Richels of Stanford
and EPRI. 2 9
*
The term "CIVEX" was coined by EPRI during 1978 studies. 1 0
4
34
0
Figure12
THOrEX Process T
Separate Processing of Blanket and
Figure 13
THOREX Process T2 : Coprocessing of Core and Blanket Fuel
Core Fuel
STORAGE OF
SPENT FUEL
CORE AND
BLANKET
FIRST STAGE EXTRACTION
U-233, U-238,
Pu, FP
THORIUM
COPROCESSING
I
U-233, U-238,
Pu
Figure 1.4
I
Chemical Flowsheet for THOREX Pvocess
23
3U PRODUCT
FIRSOUT
PRODUCTS
35
3.
Strategy C: Denatured Thorium Alternative
A number of studies were reviewed concerning the denatured thori'um
fuel cycle alternative, including Kasten et al. at ORNL, Matzie et al.
at CE, DeBrogli et al. at GA and a group of Princeton researchers.
The
work of Kasten et al. at ORNL was an assessment of the thorium fuel cycle
in power reactors.30
That report concluded that relative to thermal
reactors, better U308 utilization is possible using thorium fuel cycles
than can be achieved with uranium cycles.
However, thorium use
does not change the need for FBRs so long as significant increases in
nuclear power generation are needed for long times.
They also concluded
that the thorium cycle is not economic in LWRs even at uranium prices
over $100/lb.
Of the thermal reactors, HTGRs and HWRs have the best
fuel utilization performance while HTGRs offer the best opportunity for
HWR(Th)s have about the same fuel
economic use of the thorium cycle.
utilization as HTGRs, but at a higher power cost.
In FBRs, thorium or
thorium/uranium cycles provide a more negative void coefficient of reactivity than does the uranium cycle; also, thorium in FBRs can provide
U-233 for both thermal and fast reactors increasing the ratio of thermalto-fast reactors that can be maintained in an FBR economy.
The works by Matzie et al. at Combustion Engineering were
reviewed. 3 4 ' 3 7
That work covered an assessment of thorium fuel cycles
in PWRs and the practical considerations for the development of the
thorium fuel cycle.
is
The report concludes that use of thorium in PWRs
not currently economic although, because 20% more energy can be gene-
rated per kilogram of plutonium consumed in the thorium cycle, the
thorium-based cycle represents a superior way of utilizing plutonium stockpiles.
They also conclude that thorium fueling is feasible in PWRs.
They
note that in order to achieve a significant increase in generating capacity for a given uranium ore resource,
thorium utilization must be widespread
thus making necessary the use of highly enriched uranium, a problem from a
diversion resistance perspective.
Matzie also points out that if the
presently operating once-through cycle continues as the only authorized
mode of fueling LWRs, then thorium utilization should not be employed
because the use of fully-enriched uranium in thorium requires 25% more ore.
3
36
Also, fuel cycle costs are much higher suggesting that utilities would
not opt for thorium use in PWRs.*
The work of Lignon, Brogli, Rickard and Dahlberg of General Atomic
was also examined.4'41
In that work, the authors argue 'hat utilization
of breeders and advanced converters operating on U-233/Th fuel cycles can
provide additional proliferation resistance over that of the LWR-LNFBR
(U/Pu) alternatives.Lignon and Brogli examined the economic feasibility
of an international symbiotic system based on the concept of comprehensive energy parks.
They find the combination can reduce proliferation
risk by the operation of a relatively small number of reactors fueled with
potential weapons usable material inside secured areas.
Rickard and Dahl-
berg report on the same concept, based on the work by Lignon and Brogli,
in their Science article.
They call for a strategy to "-ase the evolu-
tion of nuclear power into our energy economy by providing an array of
options against future uncertainties.... a symbiotic combination of
breeders and advanced converters, based on both the uranium and thorium
cycles (is proposed based) on the issues of weapons proliferation,
uranium resource conservation, and economics."
While the fuel in the core
of the breeder would be plutonium in GA's scenario, to sustain its operathe fuel produced for use in thermal spectrum ACR's would be U-233
tion
bred from thorium in the blanket of the breeder.
The breeder fuel fac-
tories, because of proliferation concerns, could be situated in secured
facilities.
Advanced converter reactors fueled with U-233 and Th would be
sited outside of secured areas and near load centers.
The authors
suggest that because of the intense radiation associated with the U-233, and
because of the U-232 produced as a by-product, both fresh fuel for and
spent fuel from the ACRs would be self-protected
because of the added
difficulty in extracting and enriching the material to weapons usable
.levels.
The related strategy put forth by Feiveson, Von.Hippel and Williams
involves the deployment of already developed types of advanced converters
*
This conclusion provided a basis for this study's exclusion of thorium
use in LWRs as a viable altern&tive.
37
(HTGRs and/or CANDUs) which they suggest can be operated effectively on
proliferation resistant once-through fuel cycles.
Unlike General Atomic,
their strategy does not include breeder reactors or reprocessing on the
basis of arguments related to extended resource utilization in the ACRs
on denatured thorium cycles and reduced demand for nuclear power.
4
I
39
IV.
A.
ALTERNATIVE FUEL CYCLE STRATEGY ECONOMICS
Busbar Electrical Generating Cost Model
The releative economics of the three fuel cycle strategies have been
compared on the basis of a simple busbar electrical generating cost model.
Since the primary differences in the economics of these fuel cycles are
due to projected differences in both capital costs and fuel cycle costs,
it was thought appropriate to base the economic comparison on the use of
a model that could estimate costs to utilities.
Projection of differences
in costs to society over the long term were also estimated
but found to
be less conclusive than the results of the simple model described here.
To estimate the busbar electricity cost, the following simplified
model was used:
(1)
e
+ e.
= e
cap
ic
+ ef + e
f
OM
mills
kWh
et = total busbar cost in mills/kWh
ecap
eOM
e
=
=
the capital cost contribution to the busbar cost
=
operating and maintenance cost
the levelized fuel cycle cost
the initial core contribution to the busbar cost
e.
iC
where, the fuel cost is given by the relation:
(2)()e f = 1000
.
E
i=l
M.C.F.
iC F
t /2
with F.
=
-
t.
T
(1-T)
(1 + r)
(1 -T)
r = (1
with M
C.
r=
T
f
fs
r
r
t
t
E
=
=
=
=
=
=
=
=
=
-
T)fbr
bb
+ f r
s s
transaction quantity involved in the ith step of the fuel
cycle (e.g., kg SWU or HM)
unit price of the ith step in 1975 dollars (e.g., $/lb.)
the effective discount rate
tax fraction
equity fraction
debt fraction
rate of return to stock holders
rate of return to bond holders
time at which payment or credit for step i will occur
(t. = 0 ++ start of irradiation of a batch)
irradiation time of steady state fuel batch
energy produced by a batch.
S
40
This simple model assumes that:
(1)
fuel expenses are treated as a depreciable investment,
(2)
rate of returns do not include an allowance for inflation and
therefore reflect deflated costs in constant 1975 dollars,
(3)
revenue and depreciation charges for each fuel cycle batch occur
at the middle of the irradiation interval, and
(4)
only equilibrium batches are considered.
For the capital cost factor in equation (2),
the following expression
was used:
(3)
1000
ec
cap
K
8760 x L
1
(lT)
U~
with:
(A/P,x,N) -
4
where: L = capacity factor
K
=
unit capital cost in 1975 $/kWe including interest
during construction
= annual fixed charge rate
(A/P,x,N) = capital recovery factor
N = lifetime of plant used for depreciation purposes
Assumptions imposed include no salvage value is computed or factored in
for retired facilities and straight line depreciation is used in
I
accounting.
The initial core cost contribution to the busbar cost (eic) is
treated in the same way as the plant capital cost:
(4) e.
= $
cost of initial core
[cs
Le
where: K
=
1000
4
KL 8760
plant capacity (kWe), and L = capacity factor.
The contribution of the initial core to the total cost is significant in
the case of advanced converter reactors because of the large fuel
inventory needed to reach a high conversion ratio for these designs.
I
41
B.
Key Assumptions/Cost Data
The following data in 1975 constant dollar
terms was employed
in assessing the relative economics of the three systems:
1.
Financing Data
T = tax fraction = 0.5
= equity/debt fractions = 0.5
fs =b
rb = rate of return to bond holders = .03
r = rate of return to stockholders = .08
S
2.
Capital Cost Data ($/kWe)
LWR:
6901-3
HWR:
1.20 x LWR (includes heavy water inventory costs) 3 1
HTGR: 1.15 x LWR18
29
LMFBR: 1.3 to 1.7 x LWR
3.
Fuel Cycle Cost Data
Thorium:
33 $/kgJU
Enrichment: 85 $/SWU 4 7
4.
Fabrication/Refabrication ($/kgHM)
95
LWR:
U5 - U8
HTGR:
HWR:
LMFBR:
5.
Pu-U
277-315
U5-U8-Th(DE)
U4-U8-Th(DE)
U5-U8-Th(DE)
U3-U8-Th(DE)
114-187
360-710
343-565
733-1335
Th
180-290
U5-U8-Th(DE)
70-114
U3-U8-Th(DE)
Th
285-456
50
Pu-U8 Core
U Blanket
Th Blanket
550-850
95
95
Reprocessing ($/kgHM)
PUREX
LWR:
AIROX
Coprocessing
Pu-238 Spiking
THOREX
THOREX for U-Pu-Th
HTGR:
HWR:
THOREX for U-Pu-Th
PUREX
LMFBR:
EPRI CIVEX
THOREX (Blanket)
200
50-60
200*
210*
200
440-900
215*
300-450
330-495*
200*
* The estimates noted were derived to include the modifications necessary
to a reference reprocessing plant.
42
6.
Spent Fuel Shipment Cost ($/kgHM)
LWR:
13
HTGR:
73
HWR:
10
LMFBR:
69
7.
Waste Shipping and Disposal Cost ($/kgHM)
LWR:
65 (185 for spent fuel storage and disposal in the
once-through operation mode)
HTGR:
65
HWR:
65
LMFBR:
140
g
All cost estimates above (1-7) are adapted from refs. 30 and 31 unless
otherwise noted.
Adjustments were made to state all costs in 1975 dollars
and to reflect more recent estimates such as DOE estimates of spent fuel
storage and disposal cost.
8.
Capacity Factors
Because of online refueling in HWRs, their capacity factor (CF)
is higher than that for LWRs. In this study, the values are
as follows:
Planned CF
Actual CF
HWR
0.85
0.75
All Other Reactors
0.75
0.65
The planned capacity factor is used as a reference in choosing the
fuel fissile enrichment; the actual capacity factor is used to
determine the actual fuel batch irradiation time, assuming irradiation until the reactivity limited burnup is reached, and the
contribution of the capital cost and the initial core cost to the
busbar cost.
In determining the relative costs of reprocessing for the different
methods examined, a reference PUREX plant is considered against which
required changes can be compared.
of four cells:
The reference PUREX plant is composed
(1) head end, (2) separation cell, (3) product conversion
cell, and (4) waste treatment cell.
The respective contributions of each
cell to the total reprocessing cost are 25%, 25%, 20%, and 30%.
Obviously,
all cost estimates given above are largely uncertain because, in most
cases, there has been little applicable experience in the U.S. in building
large scale reprocessors or advanced converter reactors. Even for those
4
43
cases where commercial facilities are operating, the costs are still
uncertain,
though less so, because of the severeimpact of changing safety
and environmental regulations.18
In this study, we make the assumption that uncertainties over capital
costs of facilities exhibit similar probability distributions and are
strongly correlated; therefore, only the expected values of these distributions need be considered.
For example, the most likely value of the LWR
capital cost was taken as the reference value and the capital costs of
other reactor types were calculated by multiplying the reference value by
the ratio of the capital cost of the advanced reactor type with the
reference LWR capital cost for which there is more agreement in the literature.
In the case of fuel reprocessing and refabrication, two estimates
were used (see above data):
(1) the high value reflects the fact that the
first plants are small in size, first-of-a-kind plants and must be used
during the first ten years of the deployment of a strategy, and (2) the
low value will be approached as economics-of-sdales are realized and
experience is accumulated after about ten years of actual commercial
operation.
C.
Results and Sensitivity of Analysis
The busbar electrical generating cost equations are now described
for each fuel cycle strategy accompanied by assumptions used in their
derivation.
1.
Support calculations are found in Appendix A.
Strategy A: LWR Once-Through Cycle With/Without Extended Burnup
For the case of the LWR once-through cycle operating under present
core and fuel management practices, the following relation was derived:
(Al) et = 21.00 + 0.096 C
t
u
For the case of the LWR once-through cycle operating under extended burnup
(i.e., reoptimized for once-through operation),
the following relation was
derived:
(A2) et = 20.78 + 0.087
Cu
where Cu = cost of natural uranium in $/lb U308 and et = total electrical
generating cost in mills/kWh.
These relations are based on the data pro-
vided in part B above, and on current studies at MIT 1 1 '1 7 '1 9 which indi-
44
cate that ore consumption and SWU usage can be reduced by at least 15%
and 4% respectively by going to higher burnup (e.g.,
by using axial and radial blankets.
%
50,000 MWd/MT) and
Ore and SWU savings assumed for the
reoptimized case above are based on the 15% and 4% figures reported in
those studies.
However, to sustain a higher burnup, the fuel will have
12
13
to be redesigned and potentially modified.
Therefore, a 50% penalty
in fabrication cost has been assumed in this calculation.
The reoptimized
design is expected to become commercial about 1990 when tests and licen13
sing activities are expected to be completed.
2.
Strategy B: Plutonium Recycle in LWRs and Breeders
In the past few years, modifications to the mixed oxide fuel cycle
The most
have been suggested to improve its proliferation resistance.
promising schemes to improve proliferation resistance are evaluated here
from the point of view of the busbar cost for both the LWR and LMFBR mixed
oxide cycles.
The following relations have been derived for the LTWR on
self-generated recycle as a function of reprocessing method employed:*
(Bl) PUREX Reprocessing:
(B2) Coprocessing:
et = 20.92 (20.96) + 0.074 Cu
same as for PUREX reprocessing
(B3) AIROX Reprocessing:
et
=
22.02 (23.77) + 0.080 Cu
(B4) Pu-238 Spiking:
et
=
21.3 (21.5) + 0.077 Cu
For the LMFBR mixed oxide cycle, the following relations have been
derived, also as a function of reprocessing method employed:
(B5) PUREX Reprocessing:
et
=
26.24 (33.42) + 0.123 CPu
(B6) EPRI CIVEX:
et = 26.54 (33.88) + 0.123 CPu
where CPu is the fissile plutonium value that makes electric utilities
indifferent between consuming plutonium in LWRs and LMFBRs, which
follow these relations as a function of LMFBR capital cost (in $/gmPu ):
= 0.65
C
- 37
- High LMFBR Capital Cost: CPu = 0.65
C
- 80
- Low LMFBR Capital Cost:
C
Pu
u
u
* The value in parenthesis corresponds to the high data value for
reprocessing and refabrication.
4
45
Note that et increases with C
because the purchase of the initial core
occurs before reactor operation starts while credit for discharged excess
plutonium occurs later and is discounted.
Note also that there is cal-
culated to be a penalty of 0.3 to 0.46 mills/kWh for the EPRI-CIVEX case
over the PUREX case which appears to be a small penalty.
Assumptions
used in deriving these relations are given in Appendix A.
3.
Strategy C: Denatured Thorium Cycles in Advanced Converters and
Breeders
The total busbar cost (et)
HTGR (denatured thorium,
--
i§ estimated for the following cases:
U-233 recycle,
U-235 makeup)
HWR (denatured thorium, U-233 recycle, U-235 makeup)
(Cl)
HTGR: et = 22.96 (24.0) + 0.054 Cmu
(C2) HWR:
et = 22.26 (23.1) + 0.056 Cu
The busbar electricity cost equations derived above for the different
strategies are displayed in Figure 15d as a function of U 3 08 price.
Clearly, much more work is needed before the present worth of the total
cost of generating a given amount of electricity can be estimated.
How-
ever, expressing economic results as has been done in this study allows
several observations to be made as follows:
(1)
At current uranium costs of 40 $/lbU 3 0 8 (1975 constant dollars),
Strategies Bl (PUREX Reprocessing; LWR (U/Pu))and B2 (Coprocessing, LWR (U/Pu)) are the most attractive alternatives.
This is the case given a PUREX reprocessing cost of 200 $/kgHM
(1975 $).
However, this cost is uncertain and higher figures
have been suggested in the literature.
When the reprocessing
cost is assumed to be 350 $/kgHM (1975 $),
the levelized fuel
cost of Bl and B2 are increased by 0.44 mills/kWh.
Moreover,
if it is assumed that savings due to recycling of uranium and
plutonium are somewhat lower than considered critical, the
levelized cost is increased by (0.06 + 0.005 C ) assuming that
u
SWU and ore savings are 18% and 30% instead of 21% and 36%.
The tradeoff between Strategies Bl/B2 and Al/A2 are shown in
Figure 15a. Note that when a high reprocessing cost and low
46
Figure -15
Results of Economic Analysis
a) Strategy A vs. B
b) Strategy B: *LWR (U/Pu) Reprocessing Methods
351--
at
301
millsAWh
1975 $
251
C.V(C/lb U3 0 8 )
Cu($/Ib U308)
83(High)=High Refabrication Cost
B3(Low)mLow Refabrication Cost
c) Strategy C: HTGR vs. HWR
d) Comparison of Strategies A, B and C
35 Range of U
.HTG.
-Range of Uncertainty
for ifsufficien
FBR System
m9/Wh-
40
80
120
Cu($/Ib U3 0 8 )
160
Cut$/Ib U3 08 )
47
SWU and ore savings are considered simultaneously,.the reoptimized LWR once-through cycle (A2) becomes more attractive until
ore costs begin to approach 80 $/lbU 3 0 8 (1975 $).
(2)
The economic penalty associated with the Pu-238 spiking scheme
For U308 prices above 60 $/lb, this scheme is
appears small.
more economic than A2, the reoptimized LWR once-through cycle.
The breakeven point is very sensitive to assumptions about
reprocessing costs and savings attainable by reoptimization
(see discussion in (1) above).
(3)
The cost penalty associated with the AIROX scheme (B3) appears
significant and is mostly due to increases in enrichment
required vis-a-vis the aqueous PUREX-based processes.
The
reoptimized once-through LWR (A2) is preferred to the AIROX
scheme until very high U 3 08 prices (>180 $/lb)
(see Appendix
A for further explanation).
(4)
The range of uncertainty associated with the self-sustaining
LMFBR economy is quite large.
The median electricity cost
value of about 30 mills/kWh is higher than the reoptimized
once-through LWR (A2) until a U 3 08 price of about 100 $/lb.
The breakeven points occur at 55 and 145 $/lb U3 0 8 respectively
for the low and high values of the breeder electricity cost
range based on low and high capital cost values respectively.
These results are not significantly affected when the EPRI CIVEX
reprocessing scheme is used instead of PUREX
since capital cost-
uncertainties so overwhelmingly outweigh fuel cost uncertainties.
(5)
For Strategy C, both the HTGR and HWR self-generated recycle
The CI/C2 lines in
denatured thorium cycles were evaluated.
Figure 15c correspond to the high and low values of reprocessing
and refabrication costs.
In the early period of the deployment
of strategy C, the high values would probably be observed;
later, costs would decrease as economics-of-scale materialize.
At 40 $/lb U 0
l cost
cost is 1.2 and 0.1
mills
kih
kWh higher than B1
and A2.' These penalties are small, amounting to only 5% of the total
busbar cost.
Also, it is important to note that one moves more
48
slowly rightward along Cl than among Bl or A2 since the U 308
consumption rate is the lowest for Cl.
This effect may not
be apparent in the early years of system deployment when the
growth rate of the system is high because of the large initial
inventory.
From these observations, it is possible to conclude that the AIROX
scheme is unattractive from an economic standpoint (although it does
exhibit some advantage from a diversion resistance standpoint - see
Section V).
Since the penalty associated with Strategy C ACRs is small
compared to Strategy B LWR (U/Pu) PUREX/Coprocessing, the decision between
the two is highly dependent on their relative diversion resistance and
commercial implementability and feasibility.
I
49
V.
ALTEINATIVE FUEL CYCLE DIVERSION RESISTANCE
Diversion Resistance Quantification Methods
A.
In a recent work completed by MIT for the Department of Energy's
NASAP program,50 seven methods for assessing the relative diversion
resistance of nuclear fuel cycles were compared.
That review revealed
a surprising degree of similarity and consistency between both attribute
definition and quantification approaches employed, finding that all but
two of the methods were based on methods related to standard utility
theory.*
The methods reviewed included work by Science Applications, Inc.
contracted by the DOE-NASAP program,52 the diversion path method developed
by Hanford Engineering Development Laboratory,
al. in the Finnish Technical Centre,
54
53
work by Silvernoinnen 'et
post-doctoral work by Papazoglu
(with the assistance of four advisors) at MIT,55 and in the doctoral
dissertaions completed at Stanford University of G. Selvadurary24 and
C. Heising.50
Differences between methods are due more to the level of
sophistication each analyst strived for in
defining their model than to
any inherent inconsistency internal to risk analysis procedures.
Applications of the methods to a sample probem involving a comparison of
both commercial and non-commercial routes to weapons usable material show
close agreement of results for those methods most firmly based on utility
theory.
The two heuristically conceived methods render conflicting
results that are probably not reliable.
(A detailed comparison of the
seven methods is found in Appendix C of this report.)
Based on this survey of available methods and the degree of sophistication required for the assessment performed in this report, the method
developed at MIT by Papazoglu et al. was chosen as most appropriate for this
use.
Employing multiattribute decision theory,
the method defines five
attributes pertinent to diversion resistance against which each fuel
*
Utility theory refers to work done by Raiffa, Keeney and others on
5
values, preferences and trade-offs evidenced in decision-making. 1
Originally developed for use in business management, the theory has
spread into other areas of decision-making, including the governmentalsocial decision making area.
50
cycle strategy can be evaluated.
follows:
(1)
These attributes were defined as
the development time or the time it
takes from start to
finish to develop a nuclear explosive using diverted nuclear material,
(2) the warning period defined as the percentage of the development task
left to complete at the time of detection by outside agents, (3) the
inherent difficulty of utilizing the technology as a source of nuclear
fissile
material defined further by a breakdown into three sub-attributes
-
the radioactivity level of the diverted material in the process, the
status of scientific and technical information knownabout the process by
the potential prolferator, and the level or criticality problem associated
with the process, (4) the weapons material quality defined as the type of
nuclear material diverted (i.e., either weapons- or reactor-grade plutonium, or enriched uranium (U-233 or U-235), and lastly, (5) the development cost of the explosive construction attempt.
To derive a quantitative indicator of the relative diversion
resistance of a given fuel cycle, a value function V(x) was defined so
that a dimensionless numerical indicator (varying from -l to 0 where -1
is
most resistant and 0 least resistant) could be caltulated.
The numeti-
cal indicators for each attribute are then multiplied by weighting
factor (A ) and summed over the total number of attributes to arrive at a
single numerical indicator for each fuel cycle.
Basically, the purpose of the value function is to provide a numerical measure of the relative attractiveness of the various proliferation
pathways available to the would-be proliferator.
independence between attributes (i.e.,
each attribute is
Assuming preferential
the proliferator's value placed on
independent of the value placed on any other attribute),
the value function is from utility theory:5 1
5
V(x -x5
1
i l
V.(x)
4
51
Because the third attribute (inherent difficulty) is divided into three
sub-attributes, the above expression becomes:
V(x
x5
1
V 1 (x)
+
2 V2 (X 2
3
+
A
3 . V3 (x3 ) +
4
V 4 (x )
3=1
+
5
5
(x5
where the value functions for each of the five attributes were derived
by Papazoglu by fitting curves obtained from expert interviews:
*
in years):
development time (x
V (x 1 ) = e
1
-
1, S
=
.49 non-crisis, .83 crisis
warning period in (%):
V 2 (X2) = eYx 2
1, y = 6.93
-
radioactivity level (in R/hr at 1 m from source):
V3 1
0
V 31 (x31)
0
1
-. 02
4
2
-. 84
-. 16
6
5
-. 96
-1
status of information (x3 2 referring to levels denoted as A, B, C....I):
32
V32
A
32)
0
D
-.01
B
-.05
E
-.16
G
-.37
criticality problems (x3 3 either "High",
V3 3 ("Low")
*
= 0,
V3 3 ("Med")
C
-.67
"Medium",
H
F
I
-.84
-.95
-.99
or "Low"):
=-0.5, V 3 3 "High") = -l
itself
"Crisis" refers to a decision environment where the NWS finds
strife,
external
or
of
internal
pressed into making the decision because
environment.
while "non-crisis" refers to a business-as-usual
52
weapons material quality (x4 refers to type of material):
V4 (r.g.Pu) = -1, V4 (w.g.Pu) = -.5
V4 (H.E. U-233) = -.25 and V 4 (H.E. U-235) = 0
and finally, for monetary development cost (106 1975 $):
= -
V (x
ax 5S; a
=
2.6 x 10 -4 ,
a
=
10- 5,
S
=
1.27 non-crisis
S = 1.9 crisis
Weighting functions (A ) derived from interviews with selected
experts utilizing a standard Delphi technique were assessed for two
hypothesized divertor decision environments - non-crisis and crisis
(Table 4).
Pareto Weights on Diversion Resistance
Attributes
Table 4
Weighting
Function
Attribute
Non-Crisis
Environment
Crisis
Environment
Development Time
A1
.13
.31
Warning Period
A2
.15
.07
Status of Information
A3 1
.38
.37
Radiation Level
A3 2
.16
.16
Criticality Problems
A3 3
.04
.04
Weapons Material Quality
A4
.03
.01
Development Cost
X5
.11
.04
This was done because it was assumed that a proliferator's choice of
pathway would be influenced by the environment in which the decision
takes place.
In a crisis situation development cost, for example, is
assumed to become less important to the hypothetical decision-maker while
development time is assumed to take a more important stature.
In the
business-as-usual or non-crisis environment, the weights assume a different
set of values.
By allowing for possible large differences in the decision-
making environment, Papazoglu et al.'s approach can account for a larger
number of possible diversion scenarios.
4
53
Combining the weights with the value functions, dimensionless numerical indicators can be calculated that vary between -l and 0 where -l
is most resistant, 0 least resistant for each examined fuel cycle. These
final numerical indicators serve as relative indicators of diversion
resistance
B.
rather than absolute values.
Application of Diversion Resistance Quantification Method to Fuel
Cycle Strategies
In this section, the relative diversion resistance of the three fuel
cycle strategies is evaluated.
For each strategy, pathways by which
nuclear material can be illicitly diverted from the fuel cycle are
defined.
Each pathway is specified by the:
(1) points of diversion,
(2) means of diversion, and (3) modes of diversion.
The second step is
the evaluation of the five proliferation attributes for each pathway.
The value of each attribute is an indicator of the relative proliferation
resistance of each pathway.
These attributes are:
1.
Development cost
2.
Warning period
3.
Inherent difficulty
4.
Weapons material quality, and
5.
Development cost
The last step is to calculate an aggregate score for each pathway based
on the values of its attributes indicating the overall resistance of
the pathway compared with the other pathways to proliferation.
1.
Strategy A: LWR Once-Through Cycle*
There exist two points at which a potential divertor might divert
nuclear material in the case of the LWR once-through cycle:
*
(1)
cooled spent fuel from storage tank, and
(2)
fresh fuel being transported to the reactor.
In this study, the difference in diversion resistance between the LWR
once-through cycle operating with or without extended burnup is considered negligible; no major difference exists from a diversion
standpoint between the two cases.
54
In each case, depending on the political incentives of the proliferator,
covert or overt routes may be chosen to acquire material for weapons.
In order to gain greater accuracy, the weapon development time is divided
into two parts: (1) preparation which includes R&D, some construction and
design, and (2) diversion, which includes activities from diversion of
sensitive materials to fabrication of the nuclear weapon(s).
If the pro-
liferator chooses to use spent fuel, an indigenous reprocessing facility,
presumably based on the PUREX process will need be built and
fuel is used, an enrichment facility
gaseous diffusion methods
if fresh
assumed based on the centrifuge or
will need be indigenously built (in this
scenario it is assumed that the NWS operates reactors only and does not
operate reprocessing or enrichment commercial facilities).
Including these considerations, the following nine pathways can be
defined as a function of indigenous technology used to process the
diverted material, mode of weapons development/preparation, mode of
material diversion and material diverted from the fuel cycle:*
1
Indigenous PUREX Reprocessor
(Al) 1.
Covert Preparation - Covert Diversion - Spent Fuel
(A2) 2.
Covert Preparation - Overt Diversion
- Spent FUel
(A3) 3.
Overt Preparation
- Overt Diversion
- Spent Fuel
Indigenous Gaseous Diffusion Enrichment Plant
4.
Covert Preparation - Covert Diversion - Fresh Fuel
5.
Covert Preparation - Overt Diversion
- Fresh Fuel
6.
Overt Preparation
- Overt Diversion
- Fresh Fuel
Indigenous Centrifuge Enrichment Plant
*
7.
Covert Preparation - Covert Diversion - Fresh Fuel
8.
Covert Preparation - Overt Diversion
- Fresh Fuel
9.
Overt Preparation
- Overt Diversion
- Fresh Fuel
Note thatovert preparation and covert diversion have not been
included because a state that overtly engages in weapons development
is not likely to covertly divert from the fuel cycle since a much
longer time to acquire the material would be required and the risk of
detection would no longer be of concern to the state.
4
55
The least diversion resistant paths which are of greatest interest to
evaluate for Strategy A relative to the other stragies are the spent
fuel - indigenous reprocessor routes (A1 , A 2 and A 3 above).
For the
purposes of this study, therefore, the enrichment plant-fresh fuel
routes are not included in the evaluation.
Each of the five attributes defined in the MIT division resistance
method have been evaluated for the three pathways A1 , A 2 and A 3 (Table
5).
An overall ranking on a scale of -1 (most resistant) to 0 (least
resistant) is computed in the furthest right-hand column.
Details
of the attribute evaluation for each pathway is given in Appendix B;
the evaluation for Path A
is
presented here as representative of the
procedure employed throughout this section of the report.
The analysis indicates the relative diversion resistance of
the
three paths given conditions of crisis and non-crisis under which the
non-weapons state must make a choice between options.
The overall
ranking indicates that the LWR once-through cycle is more resistant
(by a factor of 1.2 - 1.7) under crisis conditions than under normal
conditions because of the relatively long development time required
for each pathway.
Relative to each other, Paths A
resistant with A , the overt case
and A2 appear equally
being most resistant (by factor of
1.5) under both non-crisis and crisis conditions.
A sample calculation showing the derivation of the values in the
table is given in the following pages.
*
36
Table 5).
Factor of 1.5 = .24 (see
)
al
(e
This is a significant factor in terms of increasing the overall diversion
Recall that "0" is least resistant and "-1" is
resistance of the system.
most resistant so on this scale, a value of -.36 is significantly more
This does not, however,
resistant than -. 24 by about a factor of 1.5 times.
mean the risk is reduced by that factor as a risk evaluation would need
take into account other factors such as the probability that a NWS will
make a weapon in a~particular year, effects of sanctions, effects of noncommercial routes to weapons material, etc.
Strategy A:
Table 5
LWR - Once-Through Diversion Resistance.
Diversion of Spent Fuel is
Accomplished from the Storage Pond and the Weapon Material is attained from the PUREX
Plant Independently Built by the Non-Weapons State.
Pathway
C-C-SF
C-O-SF
0-0-SF
A
A2
A3
Development
Time
(Yrs.)
Status
of
Warning
Period Infor%
mation
Radiation
Level*
Criticality
DevelopWeapons
ment
Cogt
Material
Quality . (10 $)
Overall Ranking**
5
E x V
n
nn
Non-Crisis
Crisis
2-4
1
E(2,2)
33
Med.
R.G.Pu
6-16
-. 23
-. 4
2-4
1-3
E(2,2)
33
Med.
R.G.Pu
6-16
-. 24
-. 4
,2 )
33
Med.
R.G.Pu
6-16
-. 36
-. 44
1.5-3
40-70
E(
2
*
in R/hr at 1 m from the source.
**
given for crisis/non-crisis environments
hypothetically faced by NWS decision-maker(s).
M~J
as
57
Al:
Covert Preparation - Covert Diversion - Spent Fuel (C-C-SF)
In this scenario, development and construction of an indigenous
PUREX reprocessing plant is assumed to take place in a covert mode; the
divertable output of the PUREX plant will be reactor grade plutonium with
some 60% Pu-239. The required amount of reactor grade plutonium for a
weapon will be assumed 10 kgs.
Attribute 1: Development Time. The process of developing a weapon is
divided into five steps, namely, research development and design,
construction of facilities, diversion of nuclear material, processing of
material, and finally, fabrication of the weapon.
a. t (RD&D time) the estimate for
years, whicA breaks into:
t
ranges between 1.5 - 3.8
(1) Organization and personal allocation (1 month).
(2) Literature search (2-3 months).
(3) Equipment acquisition on a laboratory scale (1 month).
(4) Experimental work (1-3 years) and
(5) Design, which includes design of the reprocessing plant as
well as the nuclear weapon(s). Some stages of design can start simultaneously with the R&D. Our estimate is 4-6 months additional time
viewed after the end of the experimental work.
(construction time) For a small PUREX plant capable of
b. t
processing enough material for a few weapons per year, construction
time of between 4 to 6 months is estimated.
(diversion time) The proliferator is assumed to require
c. t
. Each PWR fuel assembly in the storage Dond
10 kg of Pu for a wea
(burnup of 33,000 MWd/14T) so the proliferator
has about 5 kgs of Pu
will need two fuel assemblies. In this patflway with covert diversion
assumed, it is estimated to take the proliferator approximately four
years to divert enough material with a reasonable probability of not
being detected, equivalent to a rate of half an assembly per year.
(processing time) Processing time is the shortest period
d. t
in the deveopment of a weapon. When the plant is ready, it will
take less than a week to process enough spent fuel to acquire 10 kg of Pu.
An estimate of reprocessing time of 52 hours based on work done at
A processing time
Oak Ridge National Laboratory is given in Table 6.
assumed.
also
of one week is
e. t5 (weapon fabrication time) Assuming that construction and
design of a weapon has been completed prior to diversion of material,
from the time that enough plutonium is obtained to final fabrication
of the weapon is %l week. The reason for this rather long interval
between the two limits of development time is because of uncertainties
in success of research and the long diversion time required (Fig. 16).
I
58
Table
6
Time Table for Reprocessing Spent Fuel
Saw Fuel
I
Underwater-pressure cut-off saw
8 hr (1 assembly/day)
Dissolution
Transfer sheared fuel to dissolver
Add HNO
3
8 hr
Extraction and Shipping
Transfer dissolver solution to
extractor. Pump organic solution
through extractor and stripper.
4
10 hr
Ion Exchange
Pass strip solution through ion
exchange. Wash column - elute columns.
14 hr/cycle (2 columns)
Fluoride Precipitation
Reduce to Pu-239 ascorbic acid.
Add HF.
Filter (buncher funnel) dry cake.
4 hr/batch,
4 batches/day
4
Metal Reduction
Add iodine and calcium metal.
Tamp mixture in crucible in
steel. Reduction bomb.
4
Evacuation and Backfill-Argon
Raise temperature to 600 0 C.
Cool and remove metal.
'%8 hr/batch
4 batches/day
Total:
4
52 hours
4
a
59
Attribute 2: Warning Period
During the development of a nuclear weapon under the conditions
mentioned above the only stage in which a high detection probability
exists is during the diversion of nuclear material from the fuel cycle. RD&D stages require very limited manpower and a small
chemistry laboratory can be a sufficient cover for any secret activity.
Also, the construction of a reprocessing plant does not change the
detection probability, mainly because of the very small amount of reprocessing that is required. The quality of the applied safeguards
on the spent fuel temporary storage pond is the only major factor determining the probability of detection. At the present time, most of
the IAEA inspectors are from the same country that the plant or nuclear
facility is operating in; thus, there is a finite possibility of convincing the inspector to falsify records.
In the case of non-NPT countries, semi-annual or annual accounting summary reports of the nuclear material under each agreement must
be submitted to the IAEA and delay times of more than 90 days are pracIn the case of NPT countries, the average time interval
ticed.
between the time the information is received by the IAEA is around 46
60 days and a data-processing time of 10-30 days has been observed.
In the case of an NPT state, more than three months are required,
and in the case of a non-NPT state, more than one year is required
before any diversion may be detected.
An IAEA report indicate2 5 that diversion of two fuel assemblies
Taking this into account, a procan be detected in 2-3 months.
liferator can either wait until the end of construction and steal the
two fuel assemblies required for a nuclear weapon, which means by the
time the diversion is detected the weapon is already fabricated (since
reprocessing time is 111 week, the same as fabrication), or they may
steal a smaller amount of material during the research and construction period with a very low probability of.detection. Our best estimate is that, under these circumstances, the warning period is very
small approaching a value in the range of l% of the total weapons development time (i.e., 99% of the development is finished at the time
of detection).
Attribute 3: Inherent Difficulty
a. Status of Information. Status of science and technology are
The information
ranked E(2,2) which refers to "readily available".*
relating to PUREX exists in the open literature and can be acquired by
training scientific personnel in advanced countries at universities
and/or government laboratories.
*
Status of Information: This sub-attribute is assessed as a separate
ranking of both the level of science and level of technology known
about a particular technology. The levels are: l=known, 2=readily
available, 3=unknown or classified. The letters refer to one of the
nine possible orderings of these levels: A(1,1)=best known, I(3,3)=
least known.
60
I
Figure 16
Determination of Development Time
4
4
1.5 < t1 RD&D (up to 3.84 yrs)
t
Construction of PUREX Separator
4-6 month
4
t
Diversion 4 yrs
'
.-
t4
Processing 1 week
5
time = 0
Weapon Fabrication
1 week
4
4
T
to tal
= 2-4 yrs
E
I
4
61
b. Radioactivity. Radioactivity of the materials involved in
the separation process is considered as the activity measured at 1 m
from the material in the most contaminated processing stage. In this
case, material is diverted from the spent fuel pool and is assumed
stored ten years. At this a e, the radioactivity of typical PWR fuel
produces a dose of 33 REM/hr / which is mostly gamma radiation (neutron
dose for spent fuel at 10 years is negligible compared with the gamma
contribution).
c. Criticality. This measure refers to the potential for
criticality accidents during the separation of the fissile material.
Since access to pure plutonium is not available until the last stage
of the process, serious criticality problems are not faced. The aggregate value for criticality is evaluated as "medium".
Attribute 4: WeaponsMaterialQuality
This attribute indicates the type of material that is used to
make the weapon and, in this case, reactor grade plutonium (R.G.Pu)
is assumed used with the composition shown in Fig. 17.
48
Isotope Composition of Reactor Grade Plutonium (%)
Figure 17
(Fuel Burnup of 30,000 MWD/MT)
Pu-238
Pu-239
Pu-240
Pu-241
Pu-242
1.5
58
24
11.5
5
Attribute 5: Development Cost
Development cost is estimated somewhere between 6-16 million
dollars, which breaks into:
Manpower cost
2.5 to
Chemical cost
negligible
Construction cost
3.5 to 11 million $/yr
Total
6
5 million $/yr
to 16 million $/yr
4
62
2.
Strategy B: Plutonium Recycle in LWRs and Breeders
I
Two alternatives are defined within Strategy B that might be
adopted by a non-weapons state for which diversion resistance must be
sepfrately assessed. These are defined as follows:
B*:
LWR Reprocessing; Recycle of U/Pu Only With No LMFBR
B**:
LWR/LMFBR with U/Pu Recycle
I
Each of these alternatives are now analyzed with respect to their relative diversion resistance.
4
a.
B*: LWR Reprocessing; Recyle of U/Pu Only With No LMFBR
In this system, the non-weapons state is assumed to have operating
an imported commercial reprocessing plant under IAEA full-scope safegu, Is.
To acquire weapons usable material in this system, the proli-
£
ferator can either divert material from the operating reprocessor or
build a separate clandestine reprocessing facility in which diverted
LWR long-cooled (> 10 years old) spent fuel could be processed.
These
two pathways are denoted B * and B2 *
For B1 *, the following pathways are defined:
B *: Using Imported Commerical Plant for Processing of Material for
Nuclear Weapon(s)
6
(a)
Overt Preparation - Covert Diversion
(b)
Overt Preparation - Overt Diversion
In this case, preparation of the weapon is assumed to take place overtly
since a commercial reprocessing plant is already present in the country
from which diversion is defined to occur.
Depending on the type of
commercial reprocessor assumed imported and operating in the nonweapons state at the time of diversion, the following pathways can be
defined (O=Overt, C=Covert; material diverted is from stream in plant
containing reactor-grade plutonium):
PUREX Commercial
Reprocessor
B*
B*
lal
0-C-SF
0-0-SF
(SF refers to LWR spent fuel
processed in the commercial
processor noted)
6
4
63
0-C-SF
Coprocessing
0-0-SF
Coprocessing
0-C-SF
Pu-238 Spike
0-0-SF
Pu-238 Spike
B*
la4
B*
lb4
B*
0-C-SF
AIROX
0-0-SF
AIROX
0-C-SF
Tin Nitride
B*
0-0-SF
Tin Nitride
B*
la2
B*
lb2
B*
la3
B*
PUREX-Based
Commercial Reprocessor
lb3
Non-PUREX Based
Commercial Reprocessor
1a5
lb 5
Results of the analysis for each of the ten subpathways in system B *
are given in Table
7.
The procedure followed to acquire each of the
table entries was the same as that described for Strategy A and is
documented in Appendix B.
For B2*, the following pathways are defined:
Processing of Diverted
B2*: Building Small Indigenous PUREX Plant for
LWR Long-Cooled Spent Fueld
(a)
Covert Preparation - Covert Diversion
(b)
Covert Preparation - Overt Diversion
In this case,
preparation of the weapon is assumed to take place -covertly
since, by definition, the building of the small indigenous PUREX plant
is a clandestine operation.
In the case that the proliferator is
operating a PUREX or PUREX-based CIVEX type plant, it is assumed that the
weapon development time will be decreased since the clandestine reprocessor will require less RD&D time.
Also, it is assumed
the cost of
research and development for the clandestine plant is reduced over the
case where no commercial reprocessor is present (Case A, Table 5).
The following ten pathways are defined for System.-B *
again dependent on
the type of commercial reprocessor assumed operating in the non-weapons
state:
Table 7
Strategy B:
LWR wI Reprocessing
Diversion Resistance.
Commercial Imported Reprocessing Plant Used to Divert Material.
lal
PUREX
0-0-SF
B*
lbl
Copro- 0-C-SF
cessing 0-0-SF
Ba2
lb2
Dev.
Time
(Yr)
W.P.
5
1
A(l,1)
10~ -10-6
Med.
.5
<1
A(1,1)
10~ -10-6
B(1,2)
B(l,2)
5
1
(%)
1-3
50
Inherent Difficulty_
Status of
Information
Rad.
Criti.
ExV
Cost
NonCrisis
Crisis
R.G.Pu
2
-0.18
-0.34
Med.
R.G.Pu
2
-0.09
-0.14
.66
Low
R.G.Pu
3.5-6
-0.18
-0.36
.66
Low
R.G.Pu
3.5-6
-0.11
-0.22
W.
Q.
oIs
Pu-238 0-C-SF
Spiking 0-0-SF
Ba3
lb3
A-C-SF
Ba4
AIROX
0-0-SF
Bb4
0-C-SF
Tin
Nitride 00S
0-0-F
*
S0'
la5
lb5
100
100
I(3,3)
10~4-10-6
Med.
R.G.Pu
1000
-1.00
-0.98
100
100
1(3,3)
10-5-10-6
Med.
R.G.Pu
1000
-1.00
-0.98
5
1-3
E(2,2)
6.6
Low
R.G.Pu
5.5-8
-0.23
-0.37
E(2,2)
6.6
Low
R.G.Pu
5.5-8
-0.18
-0.29
E(2,2)
.66
Low
R.G.Pu
5.5-8
-0.23
-0.37
E(2,2)
.66
Low
R.G.Pu
5.5-8
-0.18
-0.29
1.5
5
1.5
90
1-3
90
SF refers to fact that R.G.Pu comes from the LWR spent
fuel processed in the commercial reprocessor noted on the left.
a
0
65
Type of Commercial Plant
Located in Country at Time
of Clandestine Reprocessing
of Diverted Spent Fuel
2al
PUREX
B*2b 2
2a2
B*
B2b2
PUREX
Based
B*
2b3
B*
B*
2a4
2b4
C-C-SF
PUREX
C-0-SF
PUREX
C-C-SF
Coprocessing
C-O-SF
Coprocessing
C-C-SF
Pu-238 Spike
C-O-SF
Pu-238 Spike
C-C-SF
AIROX
C-O-SF
AIROX
C-C-SF
Tin Nitride
C-O-SF
Tin Nitride
NonPUREX
2a5
B*
2b 5
(SF signifies that it is LWR spent fuel being diverted from the fuel
cycle for use in a clandestine reprocessor.)
Results of the analysis for these ten pathways are given in Table 8
with details provided in Appendix B.
Table 8
Strategy B
LWR with Reprocessing, No LMFBR. Weapon Development is through
Development of a Small National PUREX Plant for Reprocessing of Diverted
Long-Cooled Spent Fuel,
C-C-SF
PUREX
C-0-SF
Copro- C-C-SF
cessing C-0-SF
B*
2al
B*
2bl
B*b2
2b2
B*
2b 2
Dev.
Time
(Yrs)
W.P.
(%)
5
1
A(1,1)
1-1.5
1-3
5.
1-1.5
Inherent Difficulty
Status of
ExV
NonCrisis
Crisis
Criti.
W. Q.
Cost
33
Med.
R.G.Pu
3.5-12
-. 19
-. 35
A(1 , 1)
33
Med.
R.G.Pu
3.5-12
-. 14
-. 26
1
B(1,2)
33
Med.
R.G.Pu
4-12
-. 12
-. 37
1-3
B(1,2)
33
Med.
R.G.Pu
4-12
-.16
-. 27
Information
Rad.
0'
0'
Pu-238 C-C-SF
Spiking C
B*
2a3
2b3
5
1
E(2,2)
33
Med.
R.G.Pu
6-16
-.26
-. 41
1.5
1-3
E(2,2)
33
Med.
R.G.Pu
6-16
-.21
-. 33
5
1
E(2,2)
33
Med.
R.G.Pu
6-16
-.26
-. 41
1.5
1-3
E(2,2)
33
Med.
R.G.Pu
6-16
-.21
-. 33
5
1
E(2,2)
33
Med.
R.G.Pu
6-16
-. 26
-. 41
1.5
1-3
E(2,2)
33
Med.
R.G.Pu
6-16
-. 21
-. 33
C-0-SF
2a4
AIROX
Tin
Nitride
C-0-SF
2b 4
-C-SF
2a5
,-0-SF
2b5
a
M
67
b.
B**:
LWR/LMFBR with U/Pu Recycle
In this system, the non-weapons state is assumed to have operating
both LWRs and LMFBRs on U/Pu recycle with commercial reprocessor(s) and
MOX fabricators also operating in the country.
It is further assumed
that all nuclear facilities are imported although the inevitable effect
of having these facilities on the enhancement of technological, scientific and experimental knowledge of the potential proliferator is also
considered.
It is again assumed, as it was for System B*, that the
proliferator can decide to divert material from the existing commercial breeder fuel reprocessor(s)
(B1 **) or develop his own clandestine
reprocessor (B2 **).
In
the case of B1 **,
the proliferator is
assumed to-divert, material
from the breeder fuel reprocessor, assumed either an EPRI-CIVEX or
PUREX reprocessor.
Two modes of operation are also hypothesized:
(a)
Overt Preparation - Covert Diversion
(b)
Overt Preparation - Overt Diversion
Again, overt preparation refers to the proliferator using an existing
commercial reprocessing plant to acquire weapons-usable material.
this case,
Commercial
PUREX
Plant in NWS
Commercial
EPRI-CIVEX
Plant in NWS
four pathways are defined:
*
lal
0-C-SF(LMFBR)
IB**
0--SF(LMFBR)
B*a
0-C-SF(LMFBR)
B**2
0-0- SF (LMFBR)
ja2
The results of the analysis for these four possible pathways is
in
In
Table 9 with details presented in
Appendix B.
given
Table 9
Strategy B;
LWR-LMFBR, Recycle U/Pu. Imported Commercial Reprocessing Plant is
Either PUREX or EPRI CIVEX; Diversion Takes Place in the Operating Reprocessing
Plant.
DevelopInherent Difficulty
ment
Warning
Criti- Weapon
Time
Period Status of
Radiation
cality Material
(Yrs)
(%)
Information
Level
Level Quality
Pathway
0-C-SF
PUREX
0-0-SF
L
B**
lal
B**
5
I
A(ll)
104-10 -6
Med.
R.G.Pu
2
-. 18
-. 34
.5
1
A(1,1)
10~ -10-6
Med.
R.G.Pu
2
-. 09
-. 14
5
1
A(1,1)
165
Med.
R.G.Pu
4-12
-.22
-. 38
40-70
A(1,1)
165
Med.
R.G.Pu
4-12
-.29
-. 36
lbl
EPRI-
0-C-SF
-a2
B**
CIVEX
I0-0-SF
B**
lb2
EXV
Cogt
NonCrisis
$) Crisis
(10
1-1.5
SF here refers to LMFBR spent fuel processed in the reprocessor noted at left;
reactor grade plutonium is the material diverted (either in pure or coprocessed
form) from commercial reprocessor.
Oo
69
For case B**, it is assumed that the proliferator develops his own
2
indigenous clandestine reprocessing plant to process diverted nuclear
spent fuel for weapons purposes.
Again, considering PUREX and EPRI-CIVEX
as the possible existing commercial breeder fuel reprocessing plants,
for the two modes of operation (a) and (b) defined earlier, four different pathways are defined as a function of the type of commercial reprocessor assumed operating at time of diversion in the NWS (where FLMFBR
refers to LMFBR fuel being diverted):*
PUREX
B**
2al
C-C-FLMFBR
B**
2bl
C-0-FLMFBR
B**
C-C-FLMFBR
B**
2b 2
C-0-FLMFBR
2a2
CIVEX
*
It is assumed in this analysis that the existence of a commercial
reprocessing plant inside a non-weapons state can increase the
status of information concerning the know-how for constructing a
clandestine reprocessor. This is the reason for the assumed
difference between case A, A and A where no commercial reprocessor
o3u
is assumed operating andis the2 cases examined under Strategy B.
Table 10
Strategy B:
EPRI-CIVEX.
Operating Reprocessing Plants: PUREX or
LWR, LMFBR, U/Pu Recycle.
Weapon Development Through Construction of a National PUREX Plant.
Diversion of Fresh Breeder Fuel (FF) or Blanket Fuel (BF)
Pathway
C-C-FF
PUREX
2all
C-O-FF
PUREX
2bll
C-C-FF
CIVEX
2a21
C-0-FF
CIVEX
2b21
C-C-BF
PUREX
B**
2a12
C-O-BF
PUREX
2b12
C-C-BF
CIVEX
2a22
C-O-BF
CIVEX
2b22
Development
Warning
Time
Period
Status.of
Information
Radiation
Criticality
Weapon
Quality
Cost
Non,
Crisis
Crisis
1-* 1.5
1
A(1,1)
Negl.
Med.
R.G.Pu
3.5-12
-. 12
-. 24
I
1-3
A(1,1)
Negl.
Med.
R.G.Pu
3.5-12
-. 12
-. 21
1-1.5
i
A(1,1)
Negl.
Med.
R.G.Pu
4-12
-. 12
-. 24
1
1-3
A(1,1)
Negl.
Med.
R.G.Pu
4-12
-. 12
-. 21
1-1.5
I
A(1,1)
Negl.
Med.
W.G.Pu
3.5-12
-. 12
-. 25
1
1-3
A(1,1)
Negl.
Med.
W.G.Pu
3.5-12
-. 12
-. 22
1-1.5
I
A(1,1)
Negl.
Med.
W.G.Pu
4-12
-. 13
-. 26
1
1-3
A(1,1)
Negl.
Med.
W.G.Pu
4-12
-. 12
-. 22
0-
K
a
71
However,
the proliferator at this stage can either divert -fresh fuel
from the LMFBR and reprocess it to acquire reactor grade putonium or
divert blanket material to acquire weapons grade plutonium.
These
possibilities for diversion of LMFBR fuel double the number of pathways
(FF = fresh fuel LMFBR; BF = blanket fuel LMFBR):
B**
2all
C-C-FF
2b11
C-0-FF
B**
2a12
B**
2b12
C-C-BF
B**
2a21
C-C-FF
Commercial
B**
C-0-FF
EPRI-CIVEX
B**
2a22
B**
2b22
C-C-BF
Commercial
PUREX Plant in
NWS
2b21
Plant in NWS
C-0-BF
C-0-BF
(Last index refers to fuel type: 1=FF;
2=BF)
Results of the analysis referring to the above eight pathways for
System B * are given in Table 10 (details in Appendix B).
3.
Strategy C: Denatured Thorium Cycles in Advanced Converters and
Breeders
A country which is operating Strategy C facilities has three routes
by which to develop a nuclear explosive capability through use of these
facilities:
C1 :
Build a Clandestine PUREX Plant and Divert Spent Fuel from an
LWR Spent Fuel Storage Pool
C2 :
Divert U-233 (or Mixture Containing U-233) from Commercial
Imported THOREX Plant
C3:
Build a Clandestine THOREX Plant to Process ACR Fresh Fuel
or FBR Spent Blanket Fuel to Acquire U-233.
Table 11
Strategy C: Denatured Thorium Cycle: Diversion from THOREX Plant and/or Spent Fuel Ponds
Development
Warning Status of
Time
Period Information
LWR
Spent
Fuel
Ponds
Radiation
Criticality
Weapons
Material
Quality
Cost
EAV
NonCrisis Crisis
Ci
5
1
B(1,2)
33
Med.
R.G.Pu
4-12
-. 21
-. 37
C-0-SF LWR
C12
1
1-3
B(1,2)
33
Med.
R.G.Pu
4-12
-. 15
-.25
0-C-U3
C2 al
1
1
B(1,2)
0
Med.
H.E.U233
2
-. 10
-. 22
0-0-U3
C2 bl
.5
1
B(1,2)
0
Med.
H.E.U233
2
-. 08
-. 15
0-C-U3
C2 a2
B(2,2)
0
Med.
R.G.Pu
4-12
-. 18
-. 30
55-77
E(2,1)
0
Med.
R. G.Pu
4-12
-. 31
-. 35
1
B(1,2)
~0
Med.
H. E.U233
3.5-12
-. 19
-. 25
1-3
B(1,2)
0
Med.
H.E.U233
3.5-12
-. 12
-. 25
CC-SF LWR
T1
T
q o u
C2b2
T
1.1
C-C-F
C3 al 1-1.5
C-0-F
C3 bl
a I
1-1.5
#a
a
L
-4
73
Depending on mode of operation, the following pathways result:
C :
Covert Preparation - Covert Diversion
Covert Preparation - Overt Diversion
C2 :
Overt Preparation - Covert Diversion
Overt Preparation - Overt Diversion
C3 :
Covert Preparation - Covert Diversion
The type of commercial imported THOREX reprocessing plant assumed operating in the NWS also influences the relative diversion resistance of
Strategy C.
In Section III, part B.3, two THOREX methods were described
(denoted T1 and T2 ).
These alternatives add to the number of conceiva-
ble pathways for cases C2 and C3 as follows:
C2 :
This scenario calls for diversion from the commercial THOREX
plant.
Since two different THOREX methods might conceivably be
imported, four pathways are possible (BF(FBR) refer to the FBR
blanket fuel containing the U-233 that is processed in the
THOREX plant noted):
C2al:
O-C-BF(FBR): T
C2b1:
0-0-BF(FBR): T1
C2a2:
O-C-BF(FBR): T2
C2b2:
0-0-BF(FBR): T
2
For C3 , the same argument applies (except only process T
C3al:
C-C-F(ACR/FBR):
C3bl:
C-0-F(ACR/FBR): T1
is considered):
T1
Thus, for Strategy C, a total of eight possible pathways have been
defined.
Results of the analysis for these eight pathways is given in
Table 11, with details found in Appendix B.
4
74
Table 12
Comparison of Strategies
Fuel Cycle Strategy
Strategy A: LWR Once-Thru
- Covert Reprocessing Facility
and Covert Diversion
. Covert Reprocess;ng Facility
and Overt Diversion
- Overt Indigenous Reprocessing
Facility and Overt Diversion
Status of
Information*
Warning Period (Level of Science,
Development (% of Task to Level of TechTime (Yrs.) be Completed) nology)
Radiation
Level
(R/hr at Im
Weapons Development Overall Ranking
from
Material Cost
5
Source)
Criticality Quality
(10' S)
X V.
2-4
1
E(2.2)
33
Medium
2-4
1-3
E(2.2)
33
Medium
40-70
E(2.21
33
1.5-3
.
Medium
Reactor
Grade Pu
Reactor
Grade Pu
Reactor
Grade Pu
6-16
-.23
6-16
-.24
6-16
-.36
Thelevelsare i = known,2 = ready
knownabouta particulartechnology
rankingofboththe levelof scienceandieveloftechnology
as a separate
T nsattributeis assessed
-Statvs of information
= least known.
or classifiedThelettersrefer to oneof the ninepossibleorderingsoftheselevels:A(1,1) = bestknown,1(3.3)
availableand3 = unkinown
Fuel Cycle Strategy
Material
Diversion
Overt Covert
Overt Covert
B1: LWR (U/Pu) without LMFBR
-PUREX Commercial Plant
-Coprocessing Com. Plant
-Pu-238 Spike Com. Plant
-AIROX Commercial Plant
-Tin Nitride (Pyrometalgy.)
.5 5
1
5
100 100
1.5 5
1.5 5
1
50
100
90
90
1
1-3
100
1-3
1-3
82 LWR + LMFBR (U/Pu)
-FUREX Commercia! Plant
-EPRI-CIVEX Com Plant
.5 5
1-1 5 5
1
40-70
1
Strategy 6: LWR and/or LMFBR
on U/Pu Recycle
-
-
Status of
Information
Warning Period (Level of Science.
Development (% of Task to Level of TechTime (Yrs.) be Completed) nology)
1
A(1,1)
B (1.2)
1 (3,3)
E (2.2)
E (2.2)
10-4-10-6
.66
104-10-6
66
.66
Medium
Low
Medium
Low
Low
RGr.Pu
R.Gr Pu
RGr.Pu
RGr Pu
R.Gr Pu
2
3.5-6
1000
5 5-8
5.5-8
-.09 -. 18
..11 -.19
-1.0 -1.0
-. 11 -.23
-JA -.23
A(1.1)
A(1.1)
10-4-10-6
165
Medium
Medium
R.Gr Pu
R.Gr Pu
2
4-12
-.09 -.18
-. 29 -22
Fuel Cycle Strategy
Strategy C: Denatured Thorium
Advanced Coverters and
Fast Breeders (U/Pu/Th)
Material
Diversion
Overt Covert
1
5
Overt Covert
1-3
1
Radiation
Level
Weapons Development Overall Ranking
(R/hr at Im
5
Material Cost
from
xX V
Source)
Criticality Quality (10' S)
33
Medium R.Gr.Pu
4
I
I
I
4
Overt Covert
(Independent of overt or covert operation)
B(1.2)
4
Overt Covert
(Independent of overt or covert operation)
Status of
Information
Warning Period (Level of Science.
Development (% of Task to Level of TechTime (Yrs.) be Completed) nology)
-Diversion from LWR Spent Fuel
Ponds with covert PUREX Plant
Built Indigenously with Commercial THOREX Plant inCountry
-THOREX Commercial Plant with
Separate Processing of FBR
Blanket and Ccre (Ti)
-THOREX Comr-trc Plant with
Coprocessing or uire and
Blanket (T )
2
- Build Clandestine THOREX Plant
to Process ACR or FBR Fuel*
Radiation
Level
Weapons Development Overall Ranking
(R/hr at1m
5
Material Cost
from
X X V
(10' S)
Criticality Quality
Sourcel
4
4-12
-.15 -.21
4
.5 1
1.1
1.1
1
1
8 (1.2)
0
55-77
4-6
E (2.2)
0
Medium High Enriched
U-233
Medium R.Gr.Pu
2
4-12
-.08 -.10
- 31 -4
4
T1
1-1 5
T1
1
T1
B(1.2)
0
Medium High Enriched
U-233
-itiiutes assessed assuming a commercial THOREXP ant operating im Nws at time ot construction of ciar'estine plant of type Ti or T2 materia j; ers'ofl
3.5-12
Tl
-.1z -. 9
isassumed to take;ace
coverily
4
75
C.
Results and Sensitivity of Analysis
A comparison of the results found in Tables 5 -11
12.*
Table
is found in
Comparing the computed overall rankings found in the furthest
columns to the right for each of the fuel cycle strategies indicates that
the LWR-LMFBR (U/Pu) fuel cycle, Strategy B, can be made as diversion
resistant as either the LWR on the once-through cycle, Strategy A, or
any combination of advanced converters operating on a denatured thorium
cycle.
It is also the case, however, that the PUREX commercial plant
pathways of Strategy B are relatively least resistant.
Yet, the most
resistant pathway for all strategies is that of the Pu-238 spiking
commercial plant with an overall ranking of -1 (the highest diversion
resistance ranking possible).
Even if a special THOREX plant that coprocesses the core with the
blanket of a breeder reactor operating in Strategy C is assumed deployed,
the overall ranking is
only -.31 for the overt case and -. 18 for the
covert diversion case, which is not as resistant as Strategy A, the oncethrough LWR (comparable overall rankings: -. 36 for overt and -.23 for
covert).
Thus, according to this analysis, the denatured thorium
alternative does not improve upon the resistance of the existing LWR
fuel cycle, and is not as resistant as the best CIVEX alternative
possible for Strategy B.
This result is based on the fact that U-233 is
easier to isotopically separate out from the natural uranium it is
coprocessed with than Pu-239 is from the many isotopes of plutonium it can
be combined with.
One possibility that requires further examination is
the denaturing of U-233 with additional isotopes of uranium, such as
U-236.
The economics and even the scientific feasibility of a THOREX
plant operating under such conditions are not known and have not been
studied, while the plutonium denaturing alternative has been more
extensively investigated.
Even without denaturing the plutonium in Strategy B, other CIVEX-like
methods can improve the diversion resistance of the U/Pu cycle to at
least that evidenced by the denatured thorium cycle operating with
* Table12 shows results for non-crisis environment only.
76
THOREX coprocessing (T2.
For example, Table 12 shows that, for both
AIROX and tin nitride processes, the resistance improves from -.09 in the
overt diversion PUREX case to -. 18 and from -. 18 in
PUREX case to -.23.
thecovert diversion
This is an increase in resistance of between a
factor of 1.3 to 2 over the PUREX case.*
that these values are relative.
Again, it is important to note
The analysis shows that the diversion
resistance of the fuelcycle can be increased above the level determined
for the PUREX process.
The different pathways analyzed for the three strategies are ranked
from least to most resistant for the cases of crisis and non-crisis
decision environments (Tables 13 and 14).
crisis environment,
The table shows, under a
that the PUREX process for LWR fuel is
least resis-
tant followed by the THOREX process for breeder fuel where blanket and
core are separately handled.
Some of the most resistant pathways include
the AIROX and tin nitride processes for LWR spent fuel processing,
the EPRI-CIVEX process for breeder fuel, and the once-through LWR cycle.
However, the Pu-238 spike process is rated as most resistant by about
a factor of three times.
In contrast, the denatured thorium alterna-
tive is ranked in the middle of the diversion resistance range with
coprocessing of spent LWR fuel showing greater resistance than the
I
THOREX plant alternative (T2 ).
For the non-crisis environment case, the least resistant route
was found to be the denatured thorium pathway where U-233 can be diverted
in relatively pure form from the blanket fuel processed in a (T1 ) type
of THOREX plant.
This pathway is followed by the commercial PUREX plant
route where R.G.Pu is diverted from the process stream for LWR spent
For the non-crisis case, some of the most resistant pathways in-
fuel.
*
It is important to note the overall rankings calculated are relative.
This study does not analyze whether or not the PUREX process is
already satisfactorily diversion resistant. The analysis does show,
however, that the diversion resistance of the fuel cycle can be
increased beyond that determined for the PUREX process (See Section
VI for further discussion).
4
77
clude the EPRI-CIVEX, AIROX and tin nitride processes followed by the
LWR once-through cycle (all three pathways), and the denatured thorium
alternative where blanket and core fuel are coprocessed (T2).
Again,
the most resistant pathway by a large factor is the Pu-238 spike
alternative.
Implications of this analysis are that, if it is deemed desirable to
improve the diversion resistance of the mixed-oxide fuel cycle, plutonium
denaturing is a promising alternative,
Other implications are that the
thorium alternative does not appear to have any significant advantage over
the once-through or recycle CIVEX alternatives from a diversion resistance
standpoint.
Further discussion of the implications of these results is
provided in Section VI of this report where the economic results are
compared and contrasted with the results reported in this section.
4
78
Table 13
Ranking of Alternatives
(Non-Crisis Environment)
Least
Resistant
4
Overall
Ranking
Mode of Diversion Fuel Type
C 2 bl
B*bl
-. 08
0-0-BF(FBR)
THOREX (T1 )
-. 09
0-0-SF(LWR)
PUREX
Blbl
-. 09
0-0-SF (LMFBR)
PUREX
(3)
C2al
-. 10
0-C-BF(FBR)
THOREX (T1 )
(4)
B*b 2
-.11
0-0-SF(LWR)
Coprocessing
(5)
C 3 bl
-. 12
C-0-F(ACR/FBR)
Clandestine THOREX and T
(6)
C1 2
-. 15
C-O-SF(LWR)
Clandestine PUREX plant
(7)
B*
-. 18
0-C-SF(LWR)
PUREX
(1)
(2)
lb 1
lal
B*
Fuel Processor Used
Ba2
B*lb4
-. 18
0-C-SF(LWR)
Coprocessing
-. 18
0-0-SF(LWR)
AIROX
B*
-. 18
0-0-SF(LWR)
Tin Nitride
B**
-. 18
0-C-SF(LMFBR)
PUREX
C2 a
-. 18
0-C-BF(FBR)
(8)
C3al
-. 19
C-C-F(ACR/FBR)
THOREX (T
2)
Clandestine THOREX and T
(9)
C1 1
-. 21
C-C-SF(LWR)
Clandestine PUREX plant
(10)
B a2
-. 22
0-C-SF(LMFBR)
EPRI-CIVEX
(11)
B*
-. 23
0-C-SF(LWR)
AIROX
la4
Bla5
A1
-. 23
0-C-SF(LWR)
Tin Nitride
-. 23
C-C-SF(LWR)
Clandestine PUREX plant
-. 24
C-O-SF(LWR)
Clandestine PUREX plant
-.29
0-0-SF (LMFBR)
EPRI-CIVEX
-. 31
0-O-BF(FBR)
THOREX (T2 )
-. 36
0-0-SF(LWR)
Clandestine PUREX plant
-l.00
0-C-SF(LWR)
Pu-238 Spike
-1.00
0-0-SF (LWR)
Pu-238 Spike
Bb5
lal
2
(12)
(13)
A2
Blb 2
(14)
C 2b 2
(15)
A3
B a
(16)
B*
Bb3
g
Most
Resistant
I
79
Table 14
Ranking of Alternatives
(Crisis Environment)
Least
Resistant
(1)
Overall
Ranking
Mode of Diversion Fuel Type
-. 14
0-0-SF(LWR)
PUREX
-. 14
0-0-SF(LMFBR)
PUREX
C 2 bl
B*b2
-. 15
0-0-BF(FBR)
THOREX (T
-. 22
0-0-SF(LWR)
Coprocessing
C 2 al
-. 22
0-C-BF(FBR)
THOREX (T 1 )
C1
-.25
C-0-SF (LWR)
Clandestine PUREX plant
-.25
C-C-F (ACR/FBR)
Clandestine THOREX and T
-. 25
C-0-F(ACR/FBR)
Clandestine THOREX and T
B*b 4
-.29
0-0-SF (LWR)
AIROX
B*
lb5
-.29
0-0-SF (LWR)
Tin Nitride
C2a2
B*
lal
-. 30
0-C-BF(FBR)
THOREX (T2 )
-. 34
0-C-SF(LWR)
PUREX
-. 34
0-C-SF(LMFBR)
PUREX
B* bl
lbl
(2)
(3)
(4)
2
C3al
C3 bl
(5)
(6)
(7)
lal
Fuel Processor Used
)
(8)
C 2b 2
-. 35
0-0-BF(FBR)
THOREX
(9)
Ba2
-. 36
0-C-SF(LWR)
Coprocessing
-.36
0-0-SF (LMFBR)
EPRI-CIVEX
-. 37
0-C-SF (LWR)
AIROX
lb 2
(10)
B
Ba5
C1 1
-. 37
0-C-SF(LWR)
Tin Nitride
-. 37
C-C-SF(LWR)
Clandestine PUREX plant
(11)
B*a
-. 38
0-C-SF(LMFBR)
EPRI-CIVEX
(12)
A1
-. 4
C-C-SF(LWR)
Clandestine PUREX plant
A
--. 4
C-0-SF(LWR)
Clandestine PUREX plant
-. 44
0-0-SF(LWR)
Clandestine PUREX plant
-1.00
0-C-SF(LWR)
Pu-238 Spike
-1.00
0-0-SF (LWR)
Pu-238 Spike
(13)
(14)
2
A3
B*
B*
Bb3
Most
Resistant
I
81
VI.
A.
CONCLUSIONS
Comparison of Economic Costs and Diversion Resistance Between
Strategies
This study has attempted a quantitative
comparison of the relative
diversion resistance and electrical generating costs of three advanced
nuclear fuel cycle strategies.
The nuclear alternatives examined
included three strategies for implementation between now and the year
2050: (1) Strategy A --
the LWR once-through cycle operating with or
without extended burnup, (2) Strategy B --
the LWR and LMFBR on a closed,
mixed-oxide fuel cycle utilizing one or more of a number of available
reprocessing technologies (e.g., PUREX, AIROX, coprocessing, etc.), and
(3) Strategy C --
the LWR on a once-through cycle combined with an
advanced converter reactor (ACR) either on a once-through cycle or
joined in symbiosis to a breeder reactor (FBR) on a closed U3/Th cycle.
The motivation for comparing diversion resistance with relative
economics has developed out of concern over nuclear proliferation risk:
o
Diversion Risks. These include mostly national but also
to some extent subnational diversion risks whereby a
previously non-weapons state might illicitly acquire
nuclear material from the commercial fuel cycle for
crude explosive construction.
However, minimizing proliferation risk by maximizing fuel cycle diversion
resistance may result in a net increase in consumers electricity costs.
Therefore, a critical attribute of these systems affecting the choice by
electric utilities
and the government is
the electricity generation cost,
a factor that must be balanced against the risk of diversion:
o
Electricity Generation Cost. This includes the capital,
operating, maintenance and fuel cycle costs of each
system which can differ significantly between strategies.
Results of the comparison between the relative diversion resistance
of the fuel cycle strategies show that the LWR/LMFBR (U/Pu) fuel cycle
can be made as diversion resistant as the once-through LWR cycle or any
combination of advanced converters operating on denatured thorium.
is possible if CIVEX-like reprocessing methods are implemented.
This
Use of
methods such as AIROX or tin nitride pyrometallurgical processes can
82
increase the LWR mixed-oxide cycle diversion resistance to levels approaching that of the LWR once-through cycle.
Similarly, use of EPRI-CIVEX like
breeder fuel reprocessing methods can accomplish the same objective for
LMFBR mixed-oxide fuel.
It was further found that denaturing plutonium
(in the case examined, through increasing the percentage of Pu-238 to
above 5 weight percent) can increase the diversion resistance of the LWR
mixed-oxide cycle to beyond the levels exhibited by the once-through LWR
cycle given that plutonium isotopes cannot be easily isotopically separated
and that once-through fuel cannot be denatured unless reprocessing occurs.
For the case of the denatured thorium cycle, it was found that coprocessing of breeder blanket and core fuel would need proceed so that
the bred
plant.
U-233 would not constitute a diversion problem in the processing
If such coprocessing was not implemented, a stream of relatively
pure U-233 would be produced causing the symbiotic thorium system to appear
no more diversion resistant than the PUREX-based LWR-LMFBR combination.
However,
by coprocessing the core with the blanket fuel, the diversion
resistance is
(Strategy A).
increased to levels achieved by the LWR once-through cycle
Even for the case where thorium fuel is
not recycled,
a
case found to be uneconomic relative to the symbotic system, the diversion
resistance of Strategy C cannot be increased to that achieved by the
denatured plutonium alternative.
This result is based on the fact that
denatured uranium, a mixture of principally two isotopes (U-233 and
U-238 for Strategy C) is
not as resistant to isotopic or chemical separation
as is denatured plutonium, a combination of several plutonium isotopes
(Pu-236,
Pu-238,
Pu-239,
Pu-240,
Economic conclusions include
(1)
Pu-241,
Pu-242).
the following:
At uranium costs of 40 $/lb U308 (1975 constant dollars),
strategies B1 (PUREX reprocessing; LWR (U/Pu)) and B2
(coprocessing, LWR (U/Pu)) are the most attractive
alternatives given expected reprocessing costs and SWU/ore
savings. Only when high reprocessing costs (> 350 $/kg HM
(1975 $))and low SWU/ore savings (18% and 30% instead of
21% and 36%) are simultaneously assumed does the reoptimized LWR once-through cycle (A2) look as attractive.
Moreover, only after ore costs of 80 $/lb U308 are
exceeded does A2 become less attractive in the high
reprocessing cost case.
83
(2)
The economic penalty associated with the Pu-238 spiking scheme
appears small.
For uranium costs above 60 $/lbU3 0 8 , this
scheme is more economic than the reoptimized LWR (A2).
(3)
The cost penalty associated with the AIROX scheme appears significant and is mostly due to increases in enrichment required
vis-a-vis the aqueous PUREX-based processes.
The reoptimized
once-through LWR (A2) is preferred to AIROX until very high ore
prices are reached (>180 $/lb).
(4)
The range of uncertainty associated with the self-sustained
LMFBR economy is quite large.
The median electricity cost is
higher than the reoptimized once-through LWR until ore prices
of >100 $/lbU 3 08 are reached. The breakeven points occur at
55 and 145 $/lbU3 0 8 respectively based on low and high capital
cost values respectively. These results are not significantly
affected when the EPRI-CIVEX reprocessing scheme is used instead
of PUREX since capital cost uncertainties dominate.
(5)
For the ACRs of strategy C, higher electricity costs are observed
than for either Strategy A or B although these penalties amount
to only 5% of the total busbar costs.
From these observations,
it
was concluded that the AIROX scheme is
attractive from an economic standpoint.
un-
Also, since the penalty associated
with the ACRs of Strategy C is small, the decision between Strategy B and
C is
highly dependent on their relative diversion resistance and commercial
implementability and feasibility.
Comparing both the results of the diversion resistance and economic
analyses, it
is concluded that use of CIVEX-like reprocessing methods can
increase the diversion resistance of the LWR-LMFBR mixed-oxide fuel cycle
to levels at least as resistant as the once-through LWR fuel cycle while
maintaining an economic advantage over both Strategies A and C.
If
plutonium denaturing is adopted for those reactors operating inside nonweapons states, the LWR(U/Pu) fuel cycle can be made at least as resistant as
the LWR once-through cycle.
Moreover,
this alternative is
found to be
more economic and conserving of ore resources than the reoptimized oncethrough cycle (A2).
B.
Regulatory,
Institutional and Industrial Acceptance Aspects
The choice the U.S.
direct its
even all
faces is
one of RD&D strategy:
efforts toward implementing Strategy A,
these.
In this section,
should the U.S.
B or C
some of the regulatory,
or perhaps
institutional
and industrial acceptance aspects of each strategy are discussed.
Since
6
84
Strategy B has been found most attractive from both an economic and diversion resistance perspective, the comparison is carried out between
The following points are dis-
Strategy A vs B and then Strategy C vs B.
cussed:
(1)
stage of development and
development differences (e.g.,
(2)
development times),
regulatory/safety aspects,
and (3)
industrial
acceptance aspects in the U.S. and elsewhere.*
1.
Strategy A vs B
With respect to development, Strategy A clearly requires less since
the LWR once-through cycle is currently the system "status quo".
However,
temporary and permanent centrally located fuel storage facilities are yet
to be designed,
built or operated.
It
is
estimated that these facilities
technical difficulty given
could be designed and built with very little
a government decision to fully implement Strategy A.
These facilities
With regard to reoptimization
could feasibly be operational by the 1990s.
of the current LWR core designs for extended burnup purposes,
nical difficulty exists.
little
tech-
Most forseeable problems relate to fuel integrity
under extended periods of operation, but many
designs will solve most of these problems.
experts agree that new fuel
However,
increased failure
rates could erase the economic advantage of going to higher burnup because
of longer forced outage rates.
This is perhaps the largest key uncertainty
surrounding the implementability of Strategy A on extended burnup.
Strategy B, on the other hand, will require design and construction
of not only appropriate fuel processing and re-fabrication facilities
but breeder reactors as well.
and fast flux facilities
MOX fuel designs.
Fuel tests on MOX assemblies in both thermal
haveproven the integrity and operability of these
Uncertainties in Strategy B relate mostly to capital
The degree to which governments of supplier nations and international
organizations will have to be directly involved in the creation and
support of new industrial infrastructures is strategy dependent. The
degree to which the U.S. government will have to intervene in utility
decisions in order to insure an orderly and efficient deployment of a
Coordination between countries with
strategy is also strategy dependent.
different and sometimes conflicting objectives may be very difficult to
Such coordination, however, is necessary if the proliferation
establish.
advantages, if any, of a particular strategy are to be realized. INFCE
is a first attempt at such a coordination.
*
4
85
cost projections for commercial breeder reactors and reprocessing facilities.
The earliest date at which the first U.S. commercial breeder prototype
could be operational is in the early 1990s.
Appropriately designed re-
processors and fabrication facilities could also be commercially demonstrated by that time.
However, relative to Strategy A, uncertainty looms
larger around Strategy B in terms of both final economics and technical
design.
both Strategy A and B may
In terms of regulatory/safety aspects,
face similar problems.
One of the more prominent is
the degree to which
regulatory difficulties will delay decisions on the final disposal of
spent fuel and/or high level waste.
This problem could be of more immed-
iate concern for Strategy A where larger volumes of waste will need be
handled because of the lack of fuel reprocessing.
However,
waste disposal
regulatory problems are not thought to present such a major difference
between strategies that the decision between them could be based on such
considerations.
Possible regulatory problems may arise in
the licensing
of reactors for use of extended burnup fuel because of arguments related
Intervening actions could well
to fuel performance and impact on safety.
hold up the implementation process for Strategy A on this basis.
Argu-
ments may be raised against a reoptimized LWR core design because of
increased fuel costs (new fabrication designs with copper lined tubing
may cost twice as much as conventional fuel).
The probability of increased
fuel failure rates as a result of higher burnup may place regulatory
establishing the relative safety of these
personnel at a disadvantage in
new core designs.
the older,
Sentiment may arise on such grounds for maintaining
yet more well known,
the United States is
Industrial acceptance in
for either Strategy A or B.
In
use of extended burnup fuel in
penetrating the market.
system for the future.
French,
fact,
not a major problem
Strategy B does not preclude the
the early stages where MOX fuel is
For many years,
just
the LWR-LMFBR was the expected
This combination is the accepted choice of the
Soviets, Germans and Japanese and is
later dates in
Brazil).
fuel designs.
likely to be implemented at
other countries pursuing nuclear development (e.g.,
As for the supporting fuel cycle,
several companies in
Korea
the U.S.
and
4
86
already have a strong, vested interest in these technologies and could be
expected to be enthusiastic over a government decision to pursue the
LWR-LMFBR route (Strategy B).
International implementation of Strategy A is already well along;
and store the spent fuel at the
several major countries operate LWRs
reactor site.
To minimize diversion resistance, long-cooled spent fuel
would need be shipped to a multi-national center located outside a nonweapons state.
Arrangements for such transactions would need establish
the economic incentives for such an operation from the perspective of the
non-weapons state involved.
For Strategy B, many alternatives for inter-
national implementation exist, some of which require more and others that
require less negotiation than for Strategy A.
Multinational reprocessing,
fabrication and disposal centers have been suggested yet many countries
are skeptical of the final economics of such ventures.57
With the adoption
of CIVEX processes, reprocessors and fabricators might be sold to NWSs
avoiding problems associated with multinational ventures while ensuring
that the recipient country feels in control of its own fuel cycle.
2.
Strategy C vs B
Development of Strategy C in the United States would require a far
greater effort than for Strategy B since neither thorium-based converter
reactors or breeder reactors have been tested or demonstrated on the scale
that has been the case for Strategy B.
In particular, the choice of a
heavy water converter would require importation under license from a foreign vendor or the creation of a new design by an American vendor.
Either
alternative is likely to take longer than a commerical demonstration of a
U/Pu based LMFBR.
THOREX-based processing is also far less developed than
are PUREX-based processing methods and again would delay the time at which
Strategy C could be fully implemented (2000-2010 vs 1990-2000 for Strategy
B).
The deployment time affects the relative competitiveness of Strategy
C vs A or B, and would have an impact on the economics of the strategy.
For example, ACRs alone may not make a significant difference on uranium
resources consumed if
by the time the ACRs are deployed most high quality
ore has already been consumed.
Again, use of HTGRs would improve the out-
look for the strategy vis-a-vis HWRs but could present a similar problem.
4
87
Designing an LMFBR that would use a thorium blanket would not be a major
problem but probably would delay the commercialization date of the first
breeder in the U.S. to the end of the century.
This would probably not
adversely affect Strategy C given ACRs can be implemented as planned.
With respect to regulatory/safety aspects, the thorium alternative
will require more regulatory activity than will Strategy B as not only
will reactors and reprocessors need be licensed but front-end facilities
as well; thorium mines and mills will need be deployed.
Reviewing the
safety aspects of these new thorium reactor types would also require much
time and effort; much debate could be expected if this country were to
implement a thorium alternative.
Although certainly not insurmountable,
these regulatory/safety related problems could considerably delay the
commercial introduction of such systems decreasing the relative economic
and ore usage advantages of this alternative.
Industrial acceptance of Strategy C is certain to be a major roadblock in implementing this strategy at least inside the U.S.
nuclear industry is
heavily committed to a uranium system,
uranium-plutonium systems.
The American
and in
the future,
Although General Atomic may be favorable to
such a strategy, it is a small component of the U.S. atomic industry.
The largest American reactor vendors are not expected to be supporters
of such a strategy,
and it is.probable American utilities
back such an initiative.
would also not
Twenty years of development and planning have
perhaps made it unlikely that American industry will willingly accept a
government mandate for implementation of a thorium-based strategy.*
Proponents argue that Strategy C has less nuclear proliferation risk
than Strategy B.
Their argument can be summarized as follows:
Weapons grade material cannot be separated by chemical
processes from fresh fuel. Since chemically separable fissile
material, plutonium, is only present in the spent fuel and in
*
An example of how difficult it can be to introduce a new reactor
system into a country whose industry is already committed to a
different system is that of the United Kingdom. In that case, LWRs
After many studies and much
are the "new" system to be introduced.
the issue remains
utilities,
and
industry
between
debate
internal
unresolved.
88
small amounts (1/5 to 1/7 of the amount in spent fuel from
uranium fueled reactors) the denatured ACR's need less
international control than more "sensitive" facilities like
reprocessing, refabrication and U-Pu fueled FBR's which
should be under closer international or multinational
control.
Since direct international control is restricted
to fewer facilities in
strategy C compared to strategy B, it is more likely to be accepted and
implemented.
Even if such direct international control turns out to be
unacceptable or infeasible, the number of "sensitive" facilities is substantially smaller in strategy C and therefore may imply less overall
proliferation risk.
However,
increase
concerns about security of Th and U-233 supply may
incentives to pursue one of the following options:
(1)
(2)
no denaturing of U-233 to increase the conversion
ratio and
shift to the U-235 fuel cycle with recycle of
U and Pu.
Schemes
Both options will result in an increase in proliferation risk.
such as a U-233 and Th stockpile
security of supply problem.
might be part of the solution to the
Clearly the proliferation advantage of this
strategy, if any, is conditional on the existence of stable and smoothly
operating markets for Th and U-233.
To deploy either the thorium-based symbiotic system or the LWR-ACR
combination on an international basis, a commitment by several of the
That is,
major suppliers of nuclear technology would be necessary.
nonproliferation advantage of strategy C is
tance throughout the world.
conditional on its
the
wide accep-
Even if the U.S. choice is to develop and
demonstrate only technologies in strategy C, the choice does not guarantee
that strategy C will be the one chosen for deployment in the rest of the
world (or even in the U.S.) by the year 2000 when commercial demonstration
programs would be complete.
In order to get the strategy so well deployed
as to begin to really impact on proliferation risk, it is likely a commitment to the strategy would be necessary by all major suppliers.
lihood of such a commitment taking place is
very small.
The like-
Even given the
possibility for such a joint commitment to materialize, many decisions
previously taken independently will have to be coordinated.
This coordin-
I
89
ation will be required at two levels:
(1)
between natio'ns and (2)
between
utilities in countries where there is no central planning of capacity
expansion decisions.
goals:
is
(1)
Coordination is
necessary to reach the following
to maximize the fraction of the demand for nuclear power that
produced by the symbiotic system and (2)
to get a value of the ratio
of ACRs to FBRs as large as possible compatible with, for example,
strategy C. Starting with ACR's and then evolving toward symbiotic systems,
the ACR/FBR ratio and the conversion ratio of the ACR's and FBR's
will have to be determined by a federal authority in order to maintain
optimal fissile
stockpiles.
Some coordination at the international
level would also be needed for the same reasons but also to provide assurance of supply of fuels to consumer countries (in
particular,
LDC's).
Western Europe and Japan proceed firmly with tbe RD&D needed to deploy
strategy B (U/Pu LWR-FBR).'
If
Western Europe &ploys
strategy B and exports
LWR's and.FBR's but not the fuel processing facilities and guarantees MOX
fuel supply (multinational ownership
of facilities located in Western
Europe might provide some assurance) then the penetration of strategy C
will depend on how it competes with strategy B in terms of cost, fuel
supply assurance and capital requirements.
fail
If the industrial countries
to agree now on a common strategy (B or C),
they are less likely to
do so in 2000 when the technologies will be demonstrated and the
test of competitiveness will be unavoidable.
Competition between strate-
gies B and C is likely to result in less cooperative effort to set up the
institutional and technical arrangements to control proliferation (international fuel stockpiles, safeguard methods, etc.) since such arrangements
are strategy dependent.
Agreement now on a strategy will not eliminate competition between
several ACR's and/or between several FBR's
but such competition is less
likely to mitigate cooperative efforts to set up institutional arrangements to control proliferation since an agreement on the nuclear proliferation problem and on its relation to civilian nuclear technolgies will be
difficult to obtain.
In summary, in making its nuclear RD&D choice, the
U.S. must consider the effects of a disagreement between industrialized
countries when assessing the nonproliferation advantage of strategy C.
4
90
C.
Study Recommendations
This study has found that through the application of reprocessing
technology based on designs that minimize access to reactor-grade plutonium (CIVEX processes),
the LWR-LMFBR mixed-oxide cycle can be made as
diversion resistant as the LWR once-through cycle.
The need for the intro-
duction of a thorium based fuel cycle based on proliferation arguments
was found to be unnecessary given CIVEX-like reprocessing methods are
adopted for the U/Pu mixed-oxide cycle.
Based on these findings, it is
recommended that the government continue efforts in the reprocessing area
with greater emphasis placed on processes that can maximize fuel cycle
diversion resistance.
Since these technologies are already scientifically
proven, pilot demonstration plants can be designed and built on a reasonable time schedule that would not justify a delay in the breeder reactor
program.
Clearly, greater emphasis should be placed on breeder reactor
development.
Continued support should be maintained for advanced converter
reactors as a possible back-up system to the LWR-LMFBR combination.
How-
ever, this support should not interfere with that provided for the breeder
program
which should be continued on a top priority level.
Work to extend
uranium fuel utilization though re-optimization of standard LWR core designs
should also be continued, but again not at the expense of a full breeder
reactor demonstration program.
Delays in the breeder program are likely
to increase the likelihood of higher uranium costs in
the long term while
also increasing the likelihood that the United States may find itself dependent on foreign advanced reactor imports if other advanced electricity
producing technologies do not materialize as expected
of the 21st century.
in
the early years
To guard against these downside risks, prudent in-
vestment in advanced reactor and fuel cycle processing technology is recommended in a program that can demonstrate these technologies before
the end of this century.
4
4
91
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Computational Methods, Vol. 1, Session 2, R.P. Omberg, Chairman, 1979.
30.
Kasten, E., et al., "Assessment of the Thorium Fuel Cycle in Power Reactors,"
ORNL/TM-5565.
31.
Haffner, D.R., et al., Thorium Assessment Program Systems Studies, TC-1064,
HEDL, February 1978.
I
a
93
32.
Parvey, A., et al., "Fuel Cycle Cost Sensitivity Analysis for LWRs
Utilizing Thorium," RPI, ANS Procs., November 1978.
33.
"Gas Cooled Reactor Commercialization Study!" RAMCO for USDOE,
03-1358, December 31, 1977.
34.
Matzie, R., "Practical Considerations for the Deployment of the Thorium
Fuel Cycle," Combustion Engineering, 1976.
35.
McNelly, et al., Study of the Developmental Status and Operational Features
of HWRs, EPRI NP-365, February 1977.
36.
Till, C.E., et al., "A Survey of Considerations Involved in Introducing
CANDU Reactors in the U.S.," ANL-76-132, January 1977.
37.
Matzie, R., et al., Assessment of Thorium Fuel Cycles in
February 1977.
38.
ANL INFCE papers, 1978, Argonne National Laboratory.
39.
Sege, C.A., et al., "The Denatured Throium Cycle--an Overview," Nuc.
42:144-149, February 1979 (HEDL).
40.
Marr, D.R., et al., "Performance of Thorium-Fueled Fast Breeders," Nuc.
Tech. 42:133-143, February 1979 (HEDL).
41.
!Lignon,D.M. and Brogli, R.H., "International Symbiosis:
and the Breeder," GA-A15272, February 1979.
42.
Albert, T.E. and Straker, E.A., "Analysis of the Proliferation Resistance
of Alternative Fuel Cycles," Science Applications, December 6, 1977.
43.
Silvennoinen, P. and Vira, J., "Quantitative Assessment of Relative Proliferation Risks from Nuclear Fuel Cycles," Technical Research Center of
Finland, 1978.
44.
Ferguson, D.E., "Simple, Quick Reprocessiong Plant," Oak Ridge National
Laboratory, Memorandum to F. Culler, 30 August 1977.
45.
Gruemm, H., "The Present Status of IAEA Safeguards on Nuclear Fuel Cycle
Facilities," IAEA Department of Safeguards, January 22, 1979 (reprinted
in ALI-ABA Nuclear Export Control Proceedings, Washington, D.C., March
PRRs,
EN-77-C-
EPRI NP-359,
Tech.
The Role of Thorium
28-29, 1979, pp. 271-326.)
46.
Farris, G., Gmelin, W. and Shmeler, V., "The IAEA Safeguard Information
System," ANS Winter Meeting, San Francisco, November 1977.
47.
Heising, C.D. and Connolly, T.J., Analyzing the Reprocessing Decision:
Plutonium Recycle and Nuclear Proliferation, EPRI NP-931, November 1978,
pp. 6-14.
48.
Selden, R.W., "Reactor Plutonium and Nuclear Explosives," Lawrence Livermore
Laboratory, 1978.
94
49.
Private consultation with Prof. G. Selvaduray, Nuclear Metallurgist,
San Jose State University, April 9-13, 1979.
50.
Heising-Goodman, C.D., "Quantitative Methods for Assessing Nuclear
Fuel Cycle Diversion Resistance," M.I.T. Nuclear Engineering Department,
August 1979.
51.
Keeney, R.L., Operations Research 22(1), 1974.
52.
Kendrick, H., et al., A Preliminary Methodology for Evaluating the Proliferation Resistance of Alternative Nuclear Power Systems, SAI Report
No. SAI-78-596-WA, June 15, 1977.
53.
Maltese, M.D.K., Goodwin, K.E. and Schleter, J.C., Division Path Analysis
Handbook, Vol. 1 - Methodology, Vol. 2 - Example, US ERDA, Division of
Safeguards and Security, October 1976.
54.
Papazoglu, I., et al., A Methodology for the Assessment of the Proliferation
Resistance of Nuclear Power Systems, MIT-EL-78-021, September 1978.
55.
D'Zmura, A.P., An Approach to Comparative Evaluation of Nuclear Fuel Cycle
Proliferation Risk, Novemb-ar 29, 1976.
56.
Albert, T.E. and Straker, E.A., "Analysis of the Proliferation Resistance
of Alternative Fuel Cycles," RP-620-24, SAI-77-872-LJlF, December 6, 1977.
57.
Heising-Goodman, C.D., "International Arrangements for Spent Fuel Reprocessing--the View from Developing Countries," ANS Transactions 32:365,
June 1979.
a
A-1
Appendix A
SUPPORT CALCULATIONS FOR ELECTRICAL
GENERATING COST COMPARISONS
A.
Derivation of Relations for Total Electrical Generating Cost (et
This section offers greater insight into the application of the economic
model presented in section IV by presenting the case of LWR self-generated
recycle based on PUREX reprocessing. Defined in section IV was the following simple model:
M= transaction quantity involved in the i
fuel cycle
C
=
step of the
unit price of the ith step
F. = discount factor
E
= energy produced per batch
tr
=
t
= time at which payment for step i occurs
irradiation time of a steady state fuel batch
Numerical values used in the calculations are:
Plant Capacity = 1150 MWe
tr = 3 yrs (3 batches)
}-
E = 7.21
x 109 kWh
The fuel cost component is calculated as follows:
I
z M.C.F.
e
1000
1
E
where:
M
3
C
t
F.
lb
CU$/lb
-2 yrs
1.35
99 103 SWU
85 S/SWU
-1 yr
1.25
SFabrication.-UO2
24000 kg HM
95 $/kg
-0.5 yrs
1.19
* Reprocessing &
Spent Fuel Shipment
30000 kg HM
(200+15)
* Waste disposal
30000 ig HM
65 $/kg
e U 30 8268,10
* Enrichment
-Pu02
6000
kg HM
277(315) $/kg
$/kg
5 yrs
0.7
6 yrs
0.62
A-2
Thus,
ef
2.9 (2.94) + 0.056 C
Assuming an operating and maintenance cost of 15 $/kWe (including insurance
and property taxes), then
4
eOM + e
OM cap
17
.4 2 mils
kWh
Given an initial core of 820 x 103 lb U30 8 requires
e.
= 0.6 + 0.018 C .
78
xlO3 SWU.
This implies
Adding all these factors together renders:
et= 20.92 (20.96) + 0.074 Cu
For the other reactor - nuclear fuel cycle combinations the procedure is
the same. The additional assumptions made in these other cases are as
follows:
(1)
LMFBR (U/Pu) (1000 MWe plant)
Initial core
3084 kg Pu
30500 kg HM
Core
Blanket 48000 kg HM (axial + radial)
tr = 2 yrs (core + axial blanket), 5 yrs (radial blanket)
(2)
HTGR (1000 MWe plant)
Initial feed
7440 kg HM (U235-238)
27460 kg HM (Th)
313 ST U 3 08
304 103 SWU
Annual refueling
1240 kg HM (U235-238 makeup)
4580 kg HM (self generated recycle with Th)
4
80 ST U 3 08
75 103 SWU
3510 kg Th
t7 = 6 yrs
4
A-3
(3)
CANDU
Initial feed:
110000 kg HM
102000 kg HM (Th)
297 ST U3 0
292 10
Annual Refueling:
SWU
The procedure used here was to find the value
of U-233 for which there is equality between
the levelized fuel cycle cost of U-233 consumer
reactors (no U-235 makeup) and producer reactors
(no self-generated recycle but U-235 makeup
at 20% enriched fuel).
For consumer reactors, the annual flows are:
800 kg U-233 (charge); 700 kg (discharge)
47200 kg Th
53800 kg HM (includes U-238 for denaturing)
For producer reactors:
175 ST U3
08
167 103 SWU
48800 kg Th
53800 kg HM
457 kg U-233
(discharge)
Most of these data were taken or adjusted from Ref. 31.
B.
Assumptions Used in Deriving Relations for Strategy B
1.
Bl: LWR PUREX
Self-generated recycle leads to ore savings (36%) and SWU savings (21%)
compared to the non-reoptimized once through mode. More ore and SWUs could
be saved by reoptimization of the recycle mode. However, preliminary
calculations indicate that less can be gained from reoptimization of the
recycle mode than from reoptimization of the once through mode. The busbar
costs calculated here for the recycle cases (PUREX, AIROX, etc.) must be
compared to the busbar cost calculated for the non-reoptimized once through
mode. We also assume that MOX fuel elements constitute 25% of the fuel
reload. Also, studies at MIT 11 '1 7 ' 1 9 indicate that the presence of U-236
in recycled uranium result in a 20% reduction in the value of recycled
uranium. A correction for this effect was included in this calculation.
2.
B2:
LWR Coprocessing
The flowsheet of the coprocessing plant is almost identical to the
flowsheet of the reference PUREX plant. However, the design of the coprocessing plant would have to be more complex to preclude production of
separated plutonium without significant process modifications. This is
not expected to add significantly to the reprocessing cost.
I
A-4
3.
B3:
LWR AIROX
Only fission products volatile at 400 0 C are separated in the AIROX
process. Rare earths are not removed from the recycled material. To
compensate for the poisoning effect of the remaining fission products,
the recycled material is blended with enriched uranium (10.75 w/o U-235;
4 kg of recycle material are blended with 1 kg of enriched uranium) to
obtain a fuel containing 3.45 w/o in fissile isotopes instead of the 3.0
w/o required when the recycled fuel is completely decontaminated. Ore
and SWU savings associated with the AIROX scheme were estimated and are
displayed in the following table:
ore saving
A
SWU saving
I
Compared to non-reoptimized
once through cycle (Al)
Compared to reoptimized
once through mode (A2)
23%
- 8%
10%
-12%
4
There is a SWU penalty associated with the AIROX scheme because of
the highly enriched uranium needed for blending.
For estimates of reprocessing cost it is assumed that:
o
the head-end treatment is minimal (fuel disassembly and punching)
o
the separation process is simple compared to PUREX
o
no need for product conversion
o
no liquid or solid high level waste are produced.
AIROX to PUREX Cost Ratio
Fraction of
Total PUREX
Reprocessing Cost
Head-End
0.50
0.25
Separation
0.55
0.25
Conversion
0
0.20
Waste Treatment
0
0.30
4
4
Given the assessment of the AIROX to PUREX cost ratio for each part of the
plant, it is estimated that the AIROX reprocessing cost is about 25% to 30%
of that for PUREX.
I
Because of the high gamma and beta activity of the recycled fuel,
remote refabrication is required. Because of this factor, the same
refabrication cost as for U-233/Th fuels is assumed:
360 - 710 $/kg HM.
4
A-5
4.
B4:
LWR with Pu-238 Spiking 5 ' 7
This concept involves the addition of U-236 and/or Np-237 to the uranium
fuel loaded in the reactor in such amounts that the Pu in the spent fuel
will contain a high percentage of Pu-238 (5 to 10%).
Because of the high
heat generation of Pu-238, the fabrication, assembly, and storage of a
nuclear explosive is seriously complicated. We review now the impact of this
scheme on the fuel processing costs and on ore and SWU requirements.
Assuming that 5% Pu-238 in Pu is enough to complicate severely the
fabrication of a nuclear explosive (this is still uncertain and depends
upon the level of sophistication of the diverter), then the quantities
of Np-237 and U-236 to be included in the uranium fuel are respectively
0.075 w/o (percent of heavy metal) and 0.31 w/o. To compensate for
the poisoning effect of U-236 and Np-237 the uranium fuel enrichment
must be increased from 3 w/o to about 3.2 w/o. Because of this, ore
and SWU savings due to plutonium and uranium recycle are reduced from
36% (ore) and 21.5 (SWU) in the reference PUREX scheme to 33.8% (ore)
and 13.3 (SWU) in the Pu-238 spiking scheme.
For uranium fuel fabrication, existing plants may require backfitting
depending upon the effectiveness of existing ventilation and filtration
systems because the maximum permissible concentration in air and water
of soluble Np-237 ore lower than those for uranium. Although new facilities
could be designed to satisfy the imposed MPC levels with modest additional
cost, backfitting existing plants can be an expensive exercise. We assume
a fabrication cost penalty of 5 to 10%.
For MOX fuel fabrication, the thickness of concrete shielding must
be increased to protect against the higher neutron, gamma and alpha
activity due to Pu-238. Some parts of the plant normally expected to
include "hands on" operation or lightly shielded gloveboxes have to be
redesigned for remote operation. A 10% fabrication cost penalty is assumed
here.
In reprocessing, to recover Np-237 from the spent fuel, an additional
stage would be needed in the separation cell of the reference PUREX plant.
If a 20% penalty is assumed for the cost associated with the separation
cell, the total reprocessing cost is increased by only 5%.
5.
B5:
FBR PUREX
An advanced oxide LMFBR with a compound doubling time of 12.5 years,
a fissile plutonium core inventory of 3084 kg Puf/GWe and annual reload
of 1286 kg Puf/GWe-yr was considered as reference here. One must, however,
keep in mind that such performance is still to be demonstrated.
If the compound doubling time is such that the growth of electricity
demand can be satisfied completely by the growing breeder economy, flows
of plutonium occur only within the breeder system and therefore do not
have to be accounted for in calculating the busbar cost of the breeder
system. The busbar electricity costs (in mills/kWh) under different
conditions are shown in the next table:
4
A-6
High Breeder
Capital Cost
Low Breeder
Capital Cost
High Fabrication and
Reprocessing Costs
33.42
27.57
Low Fabrication and
Reprocessing Costs
32.28
26.24
6.
B6:
LMFBR EPRI CIVEX 5
In this scheme, uranium and plutonium are coprocessed and contaminated
with fission products. The EPRI CIVEX plant will differ from the reference
PUREX plant in several respects:
(1)
the design is more complex to preclude production of separated
pure plutonium without major process modifications,
(2)
new safeguard instrumentation needs to be developed because of
the low decontamination of the product,
(3)
unless the spent fuel is reprocessed and returned to a reactor
core within 300 days after discharge, separation of Cesium-137
from the high level wastes for addition to the Pu-U product
is required to provide long term radioactive contamination;
this is going to add a new step to the separation cell of the
reprocessing plant,
(4)
there is no purification of the Pu-U product and
(5)
more shielding is required in the conversion cell because of
the low decontamination of the product.
Considering these points, a 10% reprocessing cost penalty is estimated
for EPRI CIVEX.
In refabrication, the thickness of concrete shielding must be increased
to stop the energetic gammas from the fission products. It is estimated that
the core refabrication cost penalty associated with this scheme is -20%.
Additionally, it is assumed that the presence of fission products has
negligible effects on core reactivity in fast reactors, as has been.shown
by Eich et al. at EPRI for the EPRI-CIVEX process.
7.
Cl/C2:
HTGR and HWR on Denatured Thorium Cycle
The denatured U-233 spent fuel contains Pa-233, the precursor of
U-233. Since Pa-233 has a short halflife (27 days), after a 200-day
cooling period, most of it has decayed to U-233 and there is no need to
separate Pa-233 from the fission product stream.
Irradiated thorium contains Th-228 which has energetic beta and gamma
emitters in its decay chain. For this reason, if thorium is recycled
for refabrication, remote fabrication will be needed except if the irradiated
I
A-7
thorium is stored for about 18 years to reduce the activity level to the
level of natural thorium. When irradiated thorium is mixed with very
radioactive U-233 (denatured), remote fabrication is required. When it is
mixed with fresh make-up U-235, the penalty associated with remote fabrication
is due to the thorium; in this case, it is more economic to use fresh thorium
and dispose of the irradiated thorium.
In this study, it is assumed that the irradiated thorium is discarded.
This results in an increase in waste disposal charges but also in a simplification of the reprocessing plant since thorium is not separated from the
fission products. It is further assumed that the increase in waste disposal
cost affects the reduction in reprocessing cost. Since both costs are
given in dollars per kg HM, it is unnecessary to estimate the change in waste
disposal and.reprocessing cost. Uncorrected cost estimates given in the
literature for reprocessing can therefore be used.
Since plutonium is generated in significant amounts in denatured U-233
a U-Pu
fuels, the traditional THOREX flowsheet must be modified to add
partitioning step. A plutonium purification step has also to be added to
the separation cell of the plant and a plutonium conversion step has to
be added to the conversion cell. These changes are estimated to result
in a reprocessing cost penalty of about 15% compared to the reference
THOREX reprocessing cost which is estimated by Kasten et al. to be equal
to PUREX reprocessing costs. 3 0
4
4
I
4
B-1
Appendix B
SUPPORT CALCULATIONS FOR EVALUATION
OF FUEL CYCLE DIVERSION RESISTANCE
A.
Evaluation of Attributes for Strategy A (Table 5 )
Al:
Covert Preparation - Covert Diversion-Spent Fuel (C-C-SF)
(see text, Section V B)
A2
overt Preparation - Overt Diversion-Spent Fuel (C-O-SF)
The value of attributes in this pathway are essentially the same as
for pathway
A1 .
1. Development Time
Since most of the development time is spent
on RD&D and construction of the reprocessing plant, which in this case
is similar to pathway A done in a covert mode, we estimate the same development time for C-O-SF and C-C-SF.
2.
Warning Period
much from case A
The value of the warning period does not differ
because diversion of material in this case is done
after finishing construction of the reprocessing plant.
The last two
steps toward the completion of the weapon, (i.e., processing and fabrication) take a few weeks.
However, if diversion is detected immediately,
the weapon will be approximately two weeks away from completion.
Con-
sidering the total development time of 2-4 years, this translates into
a 1-3% warning period.
3.
The value of this attribute is independent
Inherent Difficulty
of the mode of operation and therefore is the same as for
case A .
4. Weapons Material Quality
This attribute is the same as for case
A1 :
Reactor Grade Plutonium.
5.
Development Cost
Again, the bulk of development cost is for
RD&D and construction which in this case hasn't changed from the requirements for case A
.
Development cost is therefore estimated at %6-16
million $ (1975).
A3:
1.
Overt Preparation - Overt Diversion-PWR Spent Fuel
Development Time
In an overt scenario, the proliferator is
assumed able to intensify his
efforts on RD&D and hire more experts,
thus decreasing the research time.
time.
Also, he can shorten the construction
However, the development time is estimated not to be reduced
dramatically and will fall somewhere between approximately 1.5 to 3 years.
TABLE B.I
STRATEGY A (Non-Crisis)
Development
Time
x
A
V(x)
x
A2
V(x)
x
A3
V(x)
A
Warning
Period %
Status of
Information
Inherent Difficulty
Radioactivity
Criticality
Weapon
Material
Quality
Development
Cost
E(2,2)
33
Med
R. G. Pu
6-16
(-.07)
(-.16)
(-.09)
(-.5)
(-1)
(-0.01)
2-4
1-3
E(2,2)
33
Med
R. G. Pu
6-16
(-.77)
(-.13)
(-.16)
(-.09)
(-.5)
(-1)
(-0.01)
1.5-3
55
E(2,2)
33
Med
R. G. Pu
6-16
(-.67)
(-.9779)
(-.16)
(-.09)
(-.5)
(-1)
2-4
(-.77)
.13
1
.38
.15
.04
.16
.03
ELAv
-.24
(-0.01)
-. 36
.11
TABLE 8.4
STRATEGY A (Crisis)
t7j
Inherent Difficulty
Development
Time
x
V(x)
x
A2
V(x)
x
3
A
V(x)
2-4
(-.92)
2-4
(-.92)
1.5-3
(-.85)
.31
Status of
Information
Radioactivity
Criticality
Weapon
Material
Quality
E(2,2)
33
Med
R. G. Pu
6-16
(-.16)
(-.09)
(-.5)
(-1)
(-9.5x10~)
E(2,2)
33
Med
R. G. Pu
6-16
(-.13)
(-.16)
(-.09)
(-.5)
(-1)
55
E(2,2)
33
Med
R. G. Pu
6-16
(-.9779)
(-.16)
(-.09)
(-.5)
(-1)
(-9.5x10~)
.04
.01
.04
Warning
Period %
1
(-.07)
1-3
.38
.07
aba
.16
,&I
dh
Development
Cost
(-9.5x10 4 )
dl'
ELAv
-.39
B-3
2.
Warning Period
Under overt conditions, a rather dramatic
change occurs in the value of the warning period.
In this case, the
proliferator is not primarily concerned about detection and may be detected in the middle of R&D.
This will result in a warning period of
,40-70%.
3.-5.
The value of the other attributes will be the same as
for pathways A and
A2 *
1
Worksheets for Table 5
B.
are provided in Tables B.1 and B.2.
Evaluation of Attributes - Tables 7-10
B.1
Evaluation of Attributes for B* (Table 7 )
Ba
0-C-SF
lal
1.
Strategy B
Development Time
PUREX
In this case, the only major contributor
to development time is diversion time.
In this scenario, covert di-
version is assumed such that the NWS diverts material in such small
quantities that they are not assumed detected.
a MUF of < .1%.45
An IAEA report suggests
Considering this MUF and assuming the PUREX plant has
a capacity of 300 MT/y, at a capacity factor of 80%, the production
rate will be n10 kg Pu/day.
We allow the proliferator a diversion of
10,000 gm x
=
10 gm/day
without detection and assuming a nuclear device requiring '\'20 kg
Pu (reactor-grade) the following diversion time results:
t 3 (ivesio)
-
t3/(diversion) = 10
20,000 gm
d x 365 d/y
5 years
The design of the weapon can be done during this period and fabrication
time can be less than one week.
2.
Warning Period
Covert mode of operation in this case guaran-
tees a low warning period assumed to be less than 1%.
3.
Inherent Difficulty
(a) Status of Information:
the tech-
nology and science for PUREX is known to the proliferadrig country
B-4
assumed to be operating a commercial plant
is ranked A(l,l),
(b) Radioactivity:
so status of information
In this case, very low levels of
radioactivity aie dealt with because PUREX decontaminates the spent
fuel to a high degree (DF
-
=
6
10 ),
'10
(c) Criticality
and is therefore estimated at:
- 10-6 R/hr at 1 m.
In this case,.criticality is similar to Strategy A:
medium level of criticality problem.
4.
Weapons Material Quality
5.
Cost
Reactor Grade Plutonium.
There is no cost for RD&D in the case of the commercial
reprocessing plant since it is already operational.
The only cost that
applies arises from the design and construction of the weapon which is
estimated at-2 mi-lion dollars (1975 $).
Bb
0-0-SF
lb 1
1.
Development Time
PUREX
For this pathway, the proliferator is as-
sumed to be unconcerned about being detected.
It is therefore assumed
that he can acquire enough Pu for a weapon at any time.
The most
likely scenario is that the proliferator will design the weapon, which
is assumed to take six months from the moment the proliferator decides
to acquire a weapon, and at the end of weapon design and construction
divert the material.
The total development time is therefore estimated
at a 6 month duration.
2.
Warning Period
The research and design of the nuclear device
is very unlikely to be detected.
Also, the time from stealing nuclear
material and completion of the weapon is short (<1 week) so that by
the time the proliferation effort is detected, the weapon is already
built.
Therefore, a warning period of <1% is assigned.
3.
Inherent Difficulty
4.
Weapons Material Quality
5.
Development Cost
will not change from B*
1a1*
Reactor Grade Plutonium,
same as B*
lal'
A
B-5
B-*a2 0-C-SF Coprocessing
1.
(Bal)),
Development Time
the only major development time is for diversion of nuclear
material from the plant.
for Bal.
In this pathway (the same as for PUREX
The diversion time is estimated the same as
However, in this case the proliferator may develop and
design one partitioning
column to separate plutonium from uranium and
also to decontaminate the nuclear material.
Since the proliferator
is already operating a PUREX commercial reprocessing plant, the only
time involved in building a partitioning column will be the construction time which is estimated at x.5 yr, well under the range of the
diversion time of ,.5 years.
2.
Warning Period
Since diversion is done in a covert mode,
and since there is a very low probability of detection for construction
of a partitioning column, the warning period is estimated at
3.
Inherent Difficulty
(a) Status of Information:
'l-3%.
Since the
country is operating a PUREX-type plant, the science is known and technology is readily available (B(1,2)), (b) Radioactivity:
If it is
assumed that spent fuel with radioactivity of 660 R/hr and a DF of 103
for coprocessing, then the product from the coprocessing plant will have
a radioactivity of:
660
1000
(c)
Criticality:
-
.66 R/hr at 1 meter.
Low because of uranium content.
4. Weapons Material Quality
5.
Development Cost
plant to be "l.5-4 million $.
cost = 2 million $.
B*
Total:
Reactor Grade Plutonium.
We estimate the cost of the separation
Also the weapon design and fabrication
3.5-6 million $ (1975).
0-0-SF Coprocessing
=-lb 2----
1.
Development Time
In this pathway, development time consists
of the time for construction of the partitioning column, design and
construction of the weapon, processing of material and finally fabrication of material which will take "l year.
B-6
2.
Warning Period
Since development of a partitioning plant
is overt, we estimate that it can be detected somewhere in the middle
of the process so the warning period is estimated at
3.
Inherent Difficulty
Information:
the same as B*a:
la2
(c) Criticality:
B*
The same as
B(1,2),
Weapons Material Quality
5.
Development Cost
1.
2
.
50%.
(a) Status of
(b) Radioactivity:
.66 R/hr,
Low.
4.
0-C-SF
Ba
=
Reactor Grade Plutonium.
3.5-6 million $ (1975).
Pu-238 Spiking
Development time
Pu-238 produces heat
In -this pathway, spent fuel that contains
making handling and processing very difficult.
However, even if the material is processed to acquire Pu, it will still
have a rather high concentration of Pu-238 which is not tenable in a
weapon.
This means that if the Pu is used, an isotope separation
scheme for Pu would need be devised which has not been done anywhere
in the world before.
Thus a development time of 100 years is assigned
indicating the difficulty, though not the impossibility, of the task.
2.
Warning Period
With a development time of 100 years, the
warning period looses meaning; therefore, a 100% value for warning
period is assigned.
3.
Inherent Difficulty
(a) Status of Information:
The pro-
liferator would need do much research on new techniques for separating
Pu, which is presently an unknown science and technology rated at
1(3,3),
(b) Radioactivity:
In the Pu-238 spike scheme, a high decon-
tamination factor is assumed comparable to that of PUREX because the
fuel is heat spiked, not radiation spiked.
of %10~
Therefore, a radiation level
to 10-6 R/hr is assumed, (c) Criticality:
4.
Weapons Material Quality
5.
Development Cost
medium.
Reactor Grade Plutonium.
Because of the uncertainty in development
time for this pathway, 1 billion dollars is assumed to be the development
cost for this pathway (in 1975 dollars).
6
B-7
B-*b3 0-0-SF
1.
Development Time
2.
Warning Period
3.
Inherent Difficulty
as Ba3
B*3 ,
B-
Pu-238 Spike
The same as Ba
The same as B*
la3*
(a) Status of Information! same as
(b) Radioactivity:
the'same as B*a3' (c) Criticality: medium.
octv
4.
Weapons Material Quality: Reactor Grade Plutonium.
5.
Development Cost
0-C-SF
1.
1 billion $ (1975).
AIROX
Development Time
A development time of 5 years is estimated
for this pathway (mainly diversion time).
It is also assumed during
this period that the proliferator will carry out enough R&D to construct
a PUREX plant to process diverted material.
2.
Warning Period
3.
Inherent Difficulty
1-3% (the same as B*
la 2
*
(a) Status of Information:
For a pro-
liferator who has not worked with PUREX the status of information will
be E(3,3) which means science and technology is readily available in
the open literature , (b) Radioactivity:
products are the only wastes disposed of.
45
tamination factor is ~1004.
In AIROX, volatile fission
The estimate for the decon-
Therefore, radioactivity level
=
660
Low.
100 = 6.6 R/hr, (c) Criticality:
4. Weapons Material Quality
Reactor Grade Plutonium.
5.
Development Cost
In this case, a cost of 5.5 to 8 million $
is estimated which breaks into:
1.
Weapon Design & Construction Cost
2 million $
2.
RD&D
2
3.
Construction of Separation Plant
1.5-4 "
Total
55.8 million $ (1975).
TABLE L.3 B
Inherent Difficulty
Development
Time
Warning
Period %
B*
lal
5
1
(-.91) (-.98) (-.07) (-.07)
B*
lbl
.5
(-.22) (-.34)
B*
Status of
Information
Radioactivity
Criticality
Weapons
Material
Quality
A(l,l)
(0)
(0)
10-10-6
(0)
(0)
Med
(-.5) (-.5)
R. G. Pu
(-1)
2
(-6.72x10)
10 ~-10-6
(0)
Med
(-.5)
R. G. Pu
(-1)
2
(-6.72x10~)
< 1
(-.07)
A(1,1)
(0)
-0.09
-0.14
-0.18
-0.36
3.5-6
(-2.19x10-3
-0.11
-0.22
R. G. Pu
1000
-1.00
10
-.98
9
-)
(-3.4) (-5.0)
R. G. Pu
(-1)
1000
(-3.4) (-5.0)
-1.00
-.98
-. 23
-. 37
1-3
B(1,2)
.66
Low
R. G. Pu
(-.13)
(-.05)
(0)
(0)
(-1)
B*
lb2
1
(-.39) (-.56)
50
(-.13)
B(1,2)
(-0.05)
.66
(0)
Low
(0)
R. G. Pu
(-1)
Ba
1a3
100
100
1(3,3)
10~-10
Med
-.99)
(0)
1(3,3)
(-.99)
10~-410-6
(0)
Med
(-.5)
(-.)
.
3.5-6
(-2.19x10)-3
B*
lb3
100
(-1)
100
(-1)
B*
1a4
5
(-.91) (-.98)
1-3
(-0.13)
E(2,2)
(-0.16)
6.6
(-0.016)
Low
(0)
R.
G. Pu
5.5-8
(-1)
(3.6x10-3 )(3.8x104
1b4
1.5
(-.52) (-.71)
90
(-1)
E(2,2)
(-0.16)
6.6
(-0.016)
Low
(0)
R.
G. Pu
5.5-8
(-1)
(3.6x10-3)(3.8x10~)
E(2,2)
(-0.16)
.66
(0)
Low
(0)
R. G. Pu
5.5-8
(-1)
(3.6x10 -3)(3.8x10~)
R. G. Pu
5.5-8
(-1)
(3.6x10-3 )(3.8x10
B*
la5
5
(-.91) (-.98)
B*
1b5
1.5
(-.52) (-.71)
90
(-1)
E(2,2)
(-0.16)
.66
(0)
Low
(0)
NonA crisis
.13
.15
.38
.16
.04
.03
.11
A Crisis
.31
.07
.37
.16
.04
.01
.04
1-3
(-0.13)
Crisis
ZAv
-. 34
5
(1)(
Non-Crisis
Exv
-0.18
(-.91) (-.98)
(-1
Development
Cost
)
)
-. 29
-. 23
-. 37
-18
-.29
-
ooi
R-9
B*
0-0-SF
-lb4r
1.
AIROX
Development Time
In an overt preparation-diversion mode,
the proliferator may spend %'\1.5years for RD&D and construction of a
reprocessing plant
and divert material at the end of construction.
Comparing this case with A, it is considered that the presence of
commercial nuclear facilities in a state will enhance the scientific
knowledge and experience of the NWS technicians so that they may be
able to design a PUREX-type plant in a shorter period than otherwise
might be the case.
2.
Warning Period
In this case, overt preparation (RD&D) can
be detected in a few months by international intelligence forces.
Considering a development time of 1.5 years, this translates to a 90%
warning period.
3.
(b) Radioactivity:
B*
(b)
(a)
Inherent Difficulty
6.6 R/hr, (c) Criticality:
4.
Weapons Material Quality
5.
Development Cost
0-C-SF
E(2,2),
Low.
Reactor Grade Plutonium.
5.5 to 8 million $ (1975).
Tin Nitride
The same as B*
1.
Development Time
2.
Warning Period
3.
Inherent Difficulty
1a4*
The same as B*
la4*
(a) Status of Information: E(2,2),
Radioactivity: The estimate for the decontamination
tin nitride process is
Criticality:
factor of the
10
Radioactivity
(c)
Status of Information:
=
660
1000
.66 R/hr
Low.
4.
Weapons Material Quality
5.
Development Cost
5.5 to 8 million $ (1975).
Reactor Grade Plutonium
This is assumed the same as for AIROX:
TABLE B.4 B*
LWR with reprocessing, Imported Rep.
development of weapon through national PUREX.
Inherent Difficul ty
bevelopment
Time
U
0
Warning
Period %
$tatus of
Information
activity
Criticality
Weapons
Material
Quality
Radio-
Development
Cost
B*
2a1
5
(-.91) (-.98)
1
(-.07)
A(1,l)
(0)
33
(-.09)
Med
(-.5)
R. G. Pu
(-)
3.5-12
(-4.48x10
B*
2bl
1-1.5
(-.46) (-.65)
1-3
(-.13)
A(1,1)
(0)
33
(-.09)
Med
(-.5)
R. G. Pu
(-1)
B*
2a2
5
(-.91) (-.98)
1
(-.07)
B(1,2)
.05)
33
(-.09)
Med
(-.5)
B
b
2
1-1.5
(-.46) (-.65)
1-3
(-.13)
B(1,2)
(-.05)
33
(-.09)
2a3
(-.91) (-.98)
Non-Crisis
EAv
Crisis
EAv
-.19
-.35
3.5-12
(-4.48x10-3)
-.14
-.26
R. G. Pu
(-1)
4-12
(-4.48x10 )
.21
-.37
Med
(-.5)
R. G. Pu
(-1)
4-12
(-4.48x10 3
Med
R. G. Pu
6-16
-.26
-.41
(-1)
(- .01)
)
0
B*
5
1
E(2,2)
33
.16)
(- .09)
(- .5)
1-3
(-.13)
E(2,2)
(-.16)
33
(-.09)
Med
(-.5)
R. G. Pu
(-1)
6-16
(-.01)
-.21
-.33
1
(-.07)
E(2,2)
(-.16)
33
(-.09)
Med
(-.5)
R. G. Pu
(-1)
6-16
(-.01)
-.26
-.41
(-.91) (-.98)
B*
2b4
1.5
(-.52) (-.71)
1-3
(-.13)
E(2,2)
(-.16)
33
(-.09)
Med
(-.5)
R. G. Pu
(-1)
(-.01)
6-16
-.21
-.33
B*
2a5
(-.91) 5 (-.98)
1
(-.07)
E(2,2)
(-.16)
33
(-.09)
Med
(-.5)
R. (-1)
G. Fu
6-16
(-.01)
-.26
-.41
B*
2b5
1.5
(-.52) (-.71)
1-3
(-.13)
E(2,2)
(-.16)
33
(-.09)
Med
(-.5)
R. G. Pu
(-1)
6-16
(-.01)
-.21
-. 33
.15
.38
.16
.07
.38
.16
(-..07)
(-
0
B*1.5
2b3
(-.52) (-.71)
B*5
2a4
________
A Non-Crisis
.13
A Crisis
.31
_______H______
______
.04
.04
.03
.01
.11
.04..
--
B-11
B-*b5 0-0-SF
Tin Nitride
1.
Development Time
2.
Warning Period
3.
Inherent Difficulty
(b) Radioactivity:
The same as B*
lb4'
The same as B*
lb4*
(a) Status of Information: E(2,2);
.66 R/hr; (c) Criticality: Low.
4.
Weapons Material Quality
5.
Development Cost
Reactor Grade Plutonium.
5.5 to 8 million $ (1975).
The worksheet for system B* is given in Table B.3.
B.2
Worksheets for B2 are given in
B.3
B**
lal
1.
8 )
Evaluation of Attributes for B* (Table
Table B.4.
)
Evaluation of Attributes for B** (Table 9
0-C-SF (PUREX)
Development Time
(RD&D) = 0; t2 (construction)
t
=
0
because the plant already exists; t3 (diversion) = 5 years (the same
as for pathway Bal; t
(processing)and t5
fabrication) each 1 week,
Ttotal n, 5 years.
Same as for Strategy A and B*:
2.
Warning Period
3.
Inherent Difficulty
< 1%.
a) Status of Information:
Status of information is A (1,1) because the proliferator is already
operating a reprocessing plant.
b) Radioactivity: In case of a PUREX
plant, the radiation level is estimated at: 10
Same as for case A - Medium.
c) Criticality:
4.
Weapons Material Quality
5.
Development Cost
-
10-6
R/hr
at 1 m.
Reactor Grade Plutonium.
If the existing PUREX plant is used, the only
cost will be for design of the weapon and fabrication which is estimated
at 2 million $ (1975).
B~
1.
0-0-SF (PUREX)
Development Time
done in a matter of one day.
If material is diverted overtly, this can he
However, a development time of 1/2 year is
TABLE B.5
Development
Time
5
B**
lal
(-.91)
Warning
Period %
1
(-.98)
.5
(-.07)
Bf*
Inherent Difficulty
Status of
RadioInformation
activity
Criticality
Weapons
Material
Quality
A(1,1)
10~4-10-6
Med
R. G..Pu
0
(0)
(-.5)
(-1)
(6.7?x10~)
Med
R. G. Pu
2
1
A(1,1)
10-10-6
(-0.07)
(0)
(0)
1
A(1,1)
(0)
A(1,l)
Development
Cost
(-.34)
5
1-1.5
B**
lb2
X Crisis
(-.46)
(-.65)
(-0.07)
40-70
-. 98
(0)
-.018
-0.34
-0.09
-. 014
-.22
-
-0.38
(6.72x10~ )
(-.5)
(-1)
165
Med
R. G. Pu
-.23
(-.5)
(-1)
165
Med
R. G. Pu
4-12
-. 23
(-.5)
(-1)
(-4.48x10-3
4-12
BIk2
(-.91) (-0.98)
Crisis
Ehv
2
Blbi
(-.22)
Non-Crisis
Elv
(-4.48x10-3
.13
.15
.38
.16
.04
.03
.11
.31
.07
.37
.16
.04
.01
.04
-0.29
-0.36
B-13
assumed which includes design of the weapon and fabrication time.
< 1%.
2.
Warning Period
3.
Inherent Difficulty
b) Radioactivity:
c) Criticality:
A (1,1).
a) Status of Information:
Same as radioactivity for B**
lal
Medium.
10
-4
- 10
4.
Weapon Material Quality - Reactor Grade Plutonium.
5.
Development Cost
R/hr at 1 m.
2 million $ (1975).
0-C-CIVEX
B**
la2
1.
-6
The output of anEPRI-CIVEX plant is not
Development Time
desirable for weapon purposes because of the high uranium content and
The proliferator would need
low decontamination factor.
to build
Since the technology of EPRI-CIVEX is very
a partitioning column.
the proliferator may have a relatively easy task in
similar to PUREX,
building a partitioning column. However,
the diversion time is
as-sumed
the same so that the development time is
estimated at 5 years
(same as case A).
Other activities ( RD&D)
are assumed completed during the diversion
sequence.
2.
Since the detection probability for RD&D
Warning Period
and construction is very low, and processing and fabrication times are
negligible by the time the diversion is detected, the weapon is assumed
already fabricated
3.
A (1,1).
is
implying a warning period of Ou 1%.
a) Status of Information:
Inherent Difficulty
b) Radioactivity:
1 660 R/hr at 1 m.
for 1 yr old spent fuel, the radioactivity
Products of CIVEX will still contain 25%
of their radioactivity (DF = 25%):
660 x .25 = 165 R/hr.
of radioactivity requires remote handling.
This level
c) Criticality:
In terms of
criticality, there is not much difference between EPRI-CIVEX and PUREX
products; therefore, the criticality level is assessed as medium.
4.
Weapon Material Quality
5.
Development Cost
R&D money is
Reactor Grade Plutonium.
This is similar to case A except that less
required and also the- reprocessing plant doesn't need to have
a dissolver section.
must be added.
However, some expense for remote handling of material
Therefore,
the cost is
case A) to be 1,4-12 million $.
estimated (considering 6-16 million $-for
B-14
B**
-b2
0-0-CIVEX
1.
In this pathway, development time consists
Development Time
mostly of RD&D and construction time.
Comparing this case with strategy A,
it is realized that the proliferator has a higher level of information.
Therefore, RD&D time is much less than for strategy A and the total
development time will be
2.
%
Warning Period
1 - 1.5 years.
Overt RD&D and construction can be detected
so this case is similar to A3 warning period = 40 - 70%.
3.
A (1,1).
a) Status of Information:
Inherent Difficulty
165 R/hr at 1 m; this level of radioactivity
b) Radioactivity:
requires remote handling.
c) Criticality:
4.
Weapon Material Quality
5.
Development Cost
Reactor Grade Plutonium.
4 - 12 million $ (1975).
Table B.5 contains the worksheet for Table
9.
Evaluation of Attributes for B**(Table 10)
B.4
B**
2all
1.
medium.
C-C-FF (PUREX)
Development Time
t
(R&D)~ 6 months since a PUREX commercial
plant is assumed already operating in the NWS.
t2 (construction) ~ 4 months.
t3 (diversion) r% 7 months since, in this scenario, LMFBR fresh fuel is
assumed diverted which contains 10-15% r.g. Pu.
Assuming a MUF of 0.1%
and 20 kg r.g. Pu required per explosive, a MOX fabrication plant with
a capacity of 1 ton/day, the necessary amount could be diverted in 7 months:
1,000 kg/d
20 kg
= 200 days 1 7 months.
x .1% x 10%
t4 (processing)
T
total
l week, t5 (fabrication)
1
1 week (see case A1 ).
Thus,
~ 1-1.5 yrs.
2.
3.
Warning Period
Same as for A1 .
a) Status of Information:
Inherent Difficulty
b) Radioactivity:
c) Criticality:
A (1,1).
Since fresh fuel is used, radioactivity level is negligible.
Medium as for other PUREX-based processes.
4
B-15
4.
Weapon Material Quality
5.
Development Cost
Reactor Grade Plutonium.
Development cost is the same as for B*:
3.15 - 12 million $ (1975).
B**
-2b11
C-O-FF (PUREX)
1.
In this pathway, material can be diverted
Development Time
in one day.
Therefore, Ttotal = 1 year.
1 - 3%.
2.
Warning Period
3.
Inherent Difficulty
a) Status of Information:
c) Criticality:
b) Radioactivity: negligible.
B**
2a21
4.
Weapon Material Quality
5.
Development Cost
to B**
2a1
Reactor Grade Plutonium.
3.5 - 12 million $ (1975).
Development time in this case is similar
Development Time
1 - 1.5 year.
Same as for A1 .
2.
Warning Period
3.
Inherent Difficulty
b) Radioactivity:
a) Status of Information:
negligible.
c) Criticality:
4.
Weapon Material Quality
5.
Development Cost
A (1,1).
medium.
Reactor Grade Plutonium.
4 - 12 million $ (1975).
C-O-FF (EPRI-CIVEX)
The same as development time for B*
1.
Development Time
2.
Warning Period
3.
Inherent Difficulty
b) Radioactivity:
B**
medium.
C-C-FF (EPRI-CIVEX)
1.
b2
A (1,1).
2a21
-1 - 3%.
a) Status of Information:
negligible.
c) Criticality:
4.
Weapon Material Quality
5.
Development Cost
A (1,1).
medium.
Reactor Grade Plutonium.
4 - 12 million $ (1975).
C-C-BF (PUREX)
2a12--r
The same as B**
1.
Development Time
2.
Warning Period
3.
Inherent Difficulty
b) Radioactivity:
10
2a11
a 1-1.5 year.
The same as B**l
2a11
-
a) Status of Information:
10-6 R/hr at 1 m.
A (1,1).
c) Criticality:
medium.
1-1.5 year.
TABLE B.6
Development
Time
Warning
Period %
Status of
Information
B2
Inherent Difficul y
Radioactivity
Criticality
Weapons
Material
Quality
Development
Cost
Non-Crisis
EAv
Crisis
Elv
B**
2a11
1-1.5
(-.46) (-.65)
1
(-.07)
A(l,l)
0
0
(0)
Med
(-.5)
R. G. Pu
-1
3.5-12
(-4.48x10~ )
-.12
-.24
b11
2b
1
(-.39) (-.56)
1-3
(-.13)
A(1,1)
0
0
(0)
Med
(-.5)
R. G. Pu
(-1)
3.5-12
-4.68x10-3
-.12
-.21
1-1.5
(-.46) (-.65)
1
(-.07)
A(l,l)
0
0
(0)
Med
(-.5)
R. G. Pu
(-1)
4-12
-4.68x10-3
1
1-3
(-.13)
A(1,l)
0
0
(0)
Med
(-.5)
R.
(-.56)
G. Pu
(-1)
4-12
-4.48x10-3
-.12
-,21
B**
2a12
1-1.5
(-.46) (-.65)
1
(-.07)
A(1,l)
(0)
33
(-.09)
Med.
(-.5)
W. G. Pu
(-.5)
3.5-12
-4.48x10-3
-. 12
-. 25
B**
2bl2
(-.39)
1
(-.56)
1-3
(-.13)
A(1,l)
(0)
33
(-.09)
Med
(-.5)
W. G. Pu
(-.5)
3.5-12
(-4.48x10-3
-. 12
-. 22
B**
2a22
1.5
(-.52) (-.71)
1
(-.07)
A(l,l)
(0)
33
(-.09)
Med.
(-.5)
W. G. Pu
(-.5)
4-12
(-4.48x10-3
-.13
-.26
1
1-3
(-.07)
A(l,1)
(0)
33
(-.09)
Med
(-.5)
W. G. Pu
(-.5)
4-12
(-4.48x10-3
-. 12
-. 22
B**
2a21
b21
2b21
(-.39)
F**
(-.39)
(-.56)
A
.13
.15
.38
.16
.04
.03
.11
A Crisis
.31
.07
.38
.16
.04
.01
.04
F_-
0'
B-17
4.
Weapons Material Quality
5.
Development Cost
Weapons Grade Plutonium. Blanket
material has a very high concentration of Pu239 (97.7T Pu239 ).48
3.5 - 12 million $ (1975).
this case is not different from that of B**
because the same systems
2a11
are developed.
The cost in
Since blanket fuel is irradiated for a short time
(5000 MWD/MT) it is not very radioactive and therefore does not
appreciably increase handling costs.
B**
-2b12
C-0-BF (PUREX)
1.
Development Time
2.
Warning Period
3.
Inherent Difficulty
b) Radioactivity:
B22
2b11
The same as B**
2b11
low.
=
=
1 year.
1 - 3 %.
a) Status of Information: A (1,1).
c) Criticality:
4.
Weapons Material Quality
5.
Development Cost
medium.
Weapon Grade Plutonium.
3.5 - 12 million $ (1975).
C-C-BF (EPRI-CIVEX)
1.
Development Time
2.
Warning Period., The same as B*a 2 1
3.
Inherent Difficulty - a) Status of Information:
b) Radioactivity: low.
B**
The same as B**
The same as B**
2a21
c) Criticality:
4.
Weapons Material Quality
5.
Development Cost , 4
-
=
=
1-1.5 year
1-3%
A (1,1).
medium.
'Weapon Grade Plutonium.
12 million $ (1975).
C-0-BF (CIVEX)
-=2b22-=
1.
Development Time
2.
Warning Period
3.
Inherent Difficulty
b) Radioactivity:
low.
The same as B**
2b 21
The same as B**
2b21
=
=
1-1.5 year
1
-
3%.
a) Status of Information:
c) Criticality:
4.
Weapons Material Quality
5.
Development Cost
A (1,1).
medium.
Weapon Grade Plutonium.
4 - 12 million $ (1975).
Table B.6 is the worksheet for Table 10.
4
B-18
C.
Evaluation of Attributes (Table
C1 :
11), Strategy C
Build Clandestine PUREX Plant and Use LWR Fuel From Spent
Fuel Storage.
C11: C-C-SF
This case is similar to B*
2a1 except for the fact that since a PUREX
plant is not operating, the status of information will be B instead of A:
(B(1,2)).
4
However, THOREX uses the same basic principles that are used
in PUREX, namely ion exchange.
Cl2: C-O-SF
This case is similar to B*
2b1 except for the status of information
which is Bf1,2)(known science; readily available technology).
C2:
Divert U-233 From the Commercial THOREX Plant
C2al
C2 with Overt-Covert Mode of Operation & T
1. Development Time
the diversion time.
THOREX Process.
The major contributor to development time is
U-233 can be diverted from the THOREX plant and %7kg
of U-233 is needed per explosive.48
indicate that in the blanket:
Sample data for the LMFBR (Th/U)
31
Radial 5500 kg contains 140 kg U233
Axial
7687 kg contains 132 kg U233
Total 13187 kg contains 272 kg U233
or ~ 2% U233 is in the spent fuel (blanket)
If a throughput of 1 ton/day is assumed:
2
1000 kg/day X2E- = 20 kg/day U233
100
Assuming a MUF of .1%, the amount of material divertable without being
detected is:
.001 x 20 = .02 kg = 20 gm/day.
For a weapon with 7 kg U233, one year is needed to divert enough U233
in a covert mode.
during this period.
The design and construction of the weapon can be done
Only a couple of weeks after diversion is required
to fabricate the weapon which implies that the critical time is T = 1.04 years.
(We assume that diversion is from the U233 stream which goes from the
THOREX plant to the fabrication plant in THOREX case T
1 ).
6
B-19
The warning period is very low.
Warning Period
2.
The argument
is the same as for Strategy B: 1%.
is
a) Status of Information: The science
Inherent Difficulty
3.
known (ion exchange) and since the te'hnology is
b) Radioactivity:
ranked at B(1,2).
Weapons Material Quality
4.
Since THOREX output is
is
it
pure U-233,
medium.
c) Criticalit-.
radioactivity is very low.
not developed,
High enriched U-233 is used because
the blanket is mostly U-233.
Development Cost
5.
The cost of weapons fabrication and design was
estimated earlier for Strategy B at 2 million $ (1975).
C
2bl
:
C
with Overt-Overt
21
Development Time
1.
14ode of operaCion & T
THOREX Process.
Development time is the time required for
design and fabrication of the weapon and since material is diverted overtly,
almost zero.
the diversion time is
The & -ign time of the weapon is
thus
assumed to be 5 years.
Warning period is negligible (% 1%).
2.
Warning Period
3.
Inherent Difficulty
b) Radioactivity:
a) Status Of Information:
negligible.
c) Criticality:
4.
Weapons Material Quality
5.
Development Cost
B (1,2).
medium.
Highly enriched U-233.
The same as C2al = 2 million $ (1975).
C 2 a 2 : C2 with Overt-Covert gbde of Operation & T '
2
1.
Development Time
Around 400 kg (6%)
of the LMFBR core output
60
kg Pu/day assuming a
20
MUF & .1% and a total Pu requirement of 20 kg implies 60xO1 = 333 days
(6500 kg HM) is Pu.
-
For a 1 MT/day plant,
1 yr diversion time.
1000 x
0
One year is assumed enough time for the
proliferator to develop a separation column and design the weapon given
1 month for processing and fabrication.
Total ~ 1.1 year.
Warning period is low ~ 1%.
2.
Warning Period
3.
Inherent Difficulty
a) Status of Information:
Since the
proliferator is not operating a commercial PUREX plant but must develop
one
(a partitioning column) the status of information is taken as
E(2,2); readily available.
b)
Radioactivity:
negligible.
c) Criticality:
medium.
4.
Weapons Material Quality
Reactor Grade Plutonium.
TABLE B.7
STRATEGY C
Inherent Difficulty
Development
Time
C
5
Warning
Period %
Status of
Information
Radioactivity
Criticality
Weapons
Material
Quality
Development
Cost
(-.98)
1
(-.07)
B(1,2)
(-.05)
33
(-.09)
Med
(-.5)
R. G. Pu
(-1)
4-12
(-4.48x10-3
(-.56)
1-3
(-.13)
B(1,2)
(-.05)
33
(-.09)
Med
(-.5)
R. G. Pu
(-1)
4-17-3
(4.48x10 )
1.04
(-.48) (-.58)
1
(-.07)
B(1,2)
(-.05)
0
(0)
Med
(-.5)
H.E. U233
(0)
2
(6.72x10
)
.5
(-.22) (-.34)
1
(-.07)
B(1,2)
(-.05)
0
(0)
Med
(-.5)
H.E. U233
(0)
2
(6.72x10
)
1.1
(-0.42) (-0.60)
1
(-.07)
E(2,2)
(-0.16)
0
(0)
Med
(-.5)
R. G. Pu
(-1)
4-12
(-4.48x10-3
C
1.1
(-.42) (-.60)
55-77
(-.99)
E(2,2)
(-0.16)
0
(0)
Med
(-.5)
R. G. Pu
(-1)
4-12 -3~~
(-4.48x10 )
C3al
1-1.5
(-.46) (-.65)
1
(-.07)
B(1,2)
(-.05)
0
(0)
Med
(-.5)
H.E. U233
(0)
3.5-12
(-4.48x10 3
C~bl
1-1.5
(-.46) (-.65)
1-3
(-.13)
B(1,2)
(-.05)
0
(0)
Med
(-.5)
H.E. U233
(0)
3.5-12
(-4.48x10 )
1-.91)
C1 2
1
(-.39)
C
C
2bl
C
A Non-crisis
.13
.15
.38
.16
.04
.03
.11
A Crisis
.31
.07
.38
.16
.04
.01
.04
rA
Non-Crisis
EAv
Crisis
EAv
.21
.37
.15
.25
-.10
-.22
-0.08
-.15
--. 18
-. 30
.
0
-. 35
-. 19
-. 25
2
.12
-.25
.
-
B-21
We estimate development cost as 4-12 million
Development Cost
5.
$ (1975).
C2b2
C2 with Overt-Overt Mode of Operation & T2'
The diversion time is zero but one year is
Development Time
1.
still needed to do R&D and construction and
fabrication.
Therefore T = 1.1 yr.
Warning Period
2.
It is assumed that overt activities can be
detected during the first half of the task.
b) Radioactivity:
negligible.
c) Criticality:
4.
Weapons Material Quality
5.
Development Cost
C 3al
77%.
E(2,2).
medium.
Reactor Grade Plutonium.
The same as for C 2 a2
=
4-12 million $ (1975).
National THOREX Plant - Covert-Covert
bde of Cberation & T
In this scenario, the proliferator divpvts
Development Time
1.
Therefore WP = 55 -
a) Status of Information:
Inherent Difficulty
3.
1 month for processing and
fresh breeder fuel which has a 12% U-233 content by weight.
Again we
assume that the fabrication plant has a through-put of 1000 kg a day:
1000 x .12 = 120 kg U-233/day.
7
x .
1
120 x .001
of 7 kg implies:
=
Assuming a MUF of .1% and U-233 requirement
60 days.
Since the country is already
operating a THOREX plant, it is assumed that the total development and
construction time will be " 1-1.5 years and that during this period,
the proliferator can divert enough material in a covert mode.
~ 1%.
2.
Warning Period
3.
Inherent Difficulty
b) Radiation: negligible.
a) Status of Information:
c) Criticality:
4.
Weapons Material Quality
5.
Development Cost
medium.
Highly enriched U-233.
This is similar to the case where the proliferator
has a PUREX plant and builds a clandestine plant:
C3bl:
B(1,2).
~ 3.5-12 million $ (1975).
3 with Covert-Overt Mode of Uperation & T
Like C 3bl: 1-1.5 yr.
1.
Development Time
2.
Warning Period
3.
Inherent Difficulty
b) Radioactivity:
Very low (1-3%).
a) Status of Information:
negligible.
c) Criticality:
4.
Weapons Material'Quility
5.
Development Cost
B(1,2).
medium.
Highly -Enriched U-233.
3.5-12 million $ (1975).
The worksheet for Strategy C is given in Table B.7 supporting Table 10
in the text.
4
4
6
4
C-1
Appendix C
AVAILABLE DIVERSION RESISTANCE
QUANTIFICATION METHODS
Introduction
Several methods have been developed to assess the relative diversion
resistance of nuclear t'echnologies. The review presented in this appendix
(1) SAI's "CHARM" method,
compares seven of these methods including:
(2) HEDL's diversion path method, (3) SAI's ranking method, (4) Selvaduray's
(Stanford) heuristic rating-ranking approach, (5) Silvennoinen and Vira's
(Finland Technical Research Centre) vulnerability index, (6) Papazoglu et al.'s
(MIT) multi-attribute decision theory model, and (7) Heising's (StanfordEPRI) risk-benefit approach. Each of these seven methods are described in
this appendix* and are then applied to a sample problem to generate a comparison of the methods. Application to the problem involving a comparison
of commercial/non-commercial routes to weapons usable material show close
agreement of results for those methods most firmly based on utility theory.
Heuristically conceived methods render results that are probably not reliable.
A.
SAI's "CHARM" Method
The Charm method was outlined in 197656 and views proliferation risk
as the attractiveness of the fuel cycle as a target for adversary actions
leading to the fabrication of a nuclear explosive device. This "attractiveness"
is determined by a collection of characteristics which are reduced to a
single number called "Charm". This factor is defined in the form of an
equation:
T.
N
.A.P.S.D.
i=1
where
i i i
X
= charm factor,
N
= number-of diversion points,
i
T. = duration of appearance,
S. = self protection factor of material, such as radioactivity level, etc.,
A. = minimum number of locations from which material
1
is diverted,
P
= effort to process and produce a device from
stolen material, and
D. = risk of detection and the risks due to the nature
of the material.
*
Except for Papazoglu et al.'s, which is described in the main text,
section I.A.
C-2
B.
HEDL's Diversion Path Method
The diversion path method based on subnational safeguards
problems
was developed by HEDL to quantify the proliferation risk of fuel cycles. 5 3
The approach taken is quite similar to Charm. The proliferation risk of a
fuel cycle is derived from the equation:
TPWF = MAF x DPF x RMF
where
TPWF = total proliferation weight factor,
MAF
= material attractiveness factor,
DPF = distribution parameter, and
RMF = removal mode factor.
The MAF term is heuristically defined as:
MAF = MTF x MDF x RHF
where
MTF = material type factor,
MDF = material description factor, and
RHF = radiation hazard factor.
Also, DPF = /Q/Ms where Q = mass of material and Ms = material mass required
for one explosive. The removal mode factor (RMF) is intended as a means of
assigning a value to the method used to divert the special nuclear material.
Three paths were considered:
C.
RMF
Path
1
Simple Theft
0.75
Substitution of Inert Material
0.1
Substitution of Isotopic Material
SAI's Ranking. Method Development (ERDA)
SAI developed a preliminary method under ERDA auspices for eval2ting
the proliferation resistance of alternative systems as part of NASAP.
An initial attempt in this program was the development of the Charm method
described earlier. Further work evolved a multiple attribute method. This
method defined several attributes to be assessed to determine a multiple
criteria factor as opposed to a single factor through six indices: time,
resource requirements, weapons production, inherent difficulty, detectability
and interruptibility. The last three are combined into a single factor called
the failure index. A weight factor, to be determined by a decision maker
is then assigned to each index to rank the fuel cycles. Albert and Straker
0
C-3
further elaborated on these six indices in their report57 by defining
time from decision to first weapon (yrs), time from material
nine indices:
acquisition to first weapon (yrs), cost to produce first weapon (dollars),
professional personnel to produce first weapon (number of personnel),
material unattractiveness, material safeguard-ability, difficulty, detectability
For each
and interruptability (the last five indices being dimensionless).
of the five dimensionless indices, quantitative figures-of-merit were assigned
to determine "Low", "Medium", and "High" values shown in the final results
table. The figures of merit appear to vary from 0 to 25, but no explanatian
is given in the work to explain the method used to assign these figures.
Also, in Albert and Straker's application of the methods, quantitative
weighting factors were not determined although a short discussion was
made (p. 55) concerning the impact of equal weights placed on quantitative
factors and the possibility that such weights would not influence the
analysis applied to their particular sample problem. However, such
weighting factors might need be determined for applications to problems
other than the one addressed by SAI.
D.
G. Selvaduray's Heuristic Rating/Ranking Approach
Dr. G. Selvaduray of Stanford University has developed a method for
evaluating the inherent safeguardab ity of various reprocessing methods
In that work, Selvaduray devised
as one part of his doctoral thesis.
methods for thermal reactors
reprocessing
fourteen
some
which
by
a method
one of which included
parameters,
eleven
to
respect
with
could be compared
In assessing the
aspects.
materials
nuclear
strategic
safeguardability of
(or attributes)
subparameters
five
defined
Selvaduray
safeguards parameter,
method
heuristic
a
to
according
rated
be
could
the combination of which
included:
sub-attributes
five
These
he developed independently.
(1) ability to extract pure Pu from process stream without additional
processing necessary after diversion occurs, (2) location of reprocessor
(defined as either "on" or "off"-site from one or more reactors) which
impacts on transportation considerations and the size of the reprocessor
that therefore affects the material flow through the process streams,
(3) decontamination factor, a measure of the radiation level inherent
to the process stream from which material might be diverted, (4) labor
intensity, defined as the number of persons able to gain access to process
streams (measured either as "high" or "low"), and (5) the number of process
streams (measured either as "several" or "few").
Using these five attributes, Selvaduray created tables that rated
the 48 possible combinations of the five attributes (see Fig. C.1).
The rating (r) assigned to each combination was allowed to vary between
1.00 to 10.00 where each of the 48 possible combinations assumed a
These
separate rating value (e.g., 1.00, 1.17, 1.35, 1.52, etc.).
ratings (r) were then multiplied by a ranking (R) placed on safeguardability as one of the eleven main parameters used in Selvaduray's analysis.
The formula used to arrive at a final numerical "performance factor", E,
as set up by Selvaduray, is:
I
C-4
Figure C.1
Possible Combinations of Selvaduray's Safeguard Parameter
Attribute 1 I
Attribute 2
Pure Pu
Location
I
Extractable
Sub-Attributes
Attribute 3
Attribute 4
Decontamination Factor
Labor
Effluent
Intensity
Streams
I
Attribute 5
I
High
Yes
4
I
High
I
On-Site
Several
I
I
Low
No
7
I
Few
I
Off-Site
4
i
A
4
C- 5
11
.Z r.Ri
j
1
10 E R.
i=1
\i
= 1, 11 attributes
j
j
= 1,14 processes
where the denominator represents a normalization factor as derived by
Selvaduray.
E.
Silvennoinen's and Vira's Vulnerability Index
54
used a multi-attribute
The work of Silvennoinen and Vira in Finland
approach to assess proliferation risk for several fuel cycle facilities
(spent fuel storage, enrichment plants and an independent pathway followed
The authors defined six criteria
by the non-weapons state clandestinely).
to which they assigned a quantitative value. These six criteria were
(1) the minimum cost of the weapons construction
defined as follows:
once the fissile material is available, (2) the minimum time required to
produce a weapon, (3) the marginal cost incurred when a commercial civil
power program is amended to contribute to weapons production, (4) quality
of the separated material for weapons production, (5) detectability of
the conceivable clandestine weapons production and (6) accessibility
and accountability of source material or weapons-grade material. Each of
thse criteria was assigned a value from 1 to 9 using a scaling method for
The diversion
priorities in hierarchical structures as outlined by Saaty.*
following
criterion
each
of
view
in
judged
then
was
paths
the
of
resistance
47
Heising.
by
used
approach
the
The first step in the quantitative evaluation comprises the relative
weighting of the six criteria. The criteria are then applied to each
proliferation pathway in terms of the type of material that could be diverted
(1) enriched uranium fuel in a system with no enrichment
(seven in all):
facility of its own, (2) fresh MOX fuel, (3) recently discharged spent fuel,
(4) long-stored (15 yr old) spent fuel, (5) spent fuel in a final repository
(>15 yr old), (6) spent fuel in a sealed final repository not intentionally
retrievable, and (7) separated reprocessed plutonium (PUREX based reprocessor
no alternatives to PUREX were considered). Pathways 1, 3, and 4 were further
split into two routes - military and civil facilities to obtain weaponsusable material. Each pathway was evaluated separately for each of the
six criterion xj as a function of the amount yi of the source material.
The relative values x1 -x 3 were derived from data used and collected by
Heising. 3 2 The values for x4-x6 were deduced by judgmental techniques
31
The overall vulnerability index for each of the
based on Saaty's method.
seven materials examined was computed by summing up the ratings for each
attribute xj, j = 1-6 and dimultaneously weighting each attribute as follows:
Un
.)
[T
.
1+X Iw uJ (y.)
j=1
*
Saaty, T.L., "A Scaling Method for Priorities in Hierarchical Structures",
J. Math. .Psychol., Vol. 15, No. 234, 1977.
-
C- 6
where
u(y.).
=
vulnerability index of material flow level y .
j = 1-7
~ for material type j,
1
w.
3
=
weighting factor on jth attribute, j = 1 to 6
(n=6)
A
=
free parameter to normalize w.
This relation was derived explicitly from Keeny's work on utility theory 5 1
such that
1 for all j;
u)
For the case where Z w.
the familiar form: . 3
1, A
=
[ v (1+X w)
j=1
--
1
1.
0 and the equation above simplifies to
n
u(y.)
w. u
=
(y.)
j=1
n
Silvennoinen et al. observed the condition E
j=1
w. = 1 for their subjectively
'J
assigned weighting factors wj.
In their work, the authors consider the
military-civilian/commercial options as a choice a NWS could make when
deciding between the seven material types available to them. In their work,
they assume equal preference for military vs civil in computing their final
results.
In a slightly different approach to calculating the vulnerability
indices (or total value functions) for each of the seven material types,
the authors suggest the use of "fuzzy integration" as reported in Sugeno's
work. * Instead of a weighted average, the index is taken as a fuzzy
integral uF(yi) over all the criteria xj, j = 1-6:
uF(yi
where
X =
f(y., X) g(-)
{x }, a(y.,X) = u (y.) and g(')
g
is a measure of integration.
One interpretation of the fuzzy integral above is tantamount to maxmin
34
algebra:
n
uF(yi
(yiV x.) A g(F.)
3=1
where
V and Adenote maximum and minimum operations, respectively.
The set Fj and the structure of g(-) are taken from the theory of fuzzy
sets. The measure g(F) is defined by a parameter A as follows:
* Sugeno, M., in Fuzzy Automata and Decision Processes, M.M. Gupta, Editor,
North Holland Publishers, New York, 1977.
0
C-7
T
max {u(y (t) } dt + DRI
J
(1+r)-t
PRI =
T
(1 + r)-t dt
where
DRI = risk of irretrievable phase
(1+
rD)-t u(y6 (T ))
dt
T
where (1 + rD) t is a time preference factor, rD is a discount rate and
y 6 (T ) is the total amount of spent fuel disposed; T is a given time horizon,
u(yi) is the vulnerability index calculated earlier, and r is a discount
rate not necessarily equal to rD. This formulation was applied to assess
the difference between three LWR fuel cycle options with results shown in
Table C.l.
Table C.l.
Overall Proliferation Risk Index (PRI)
for Three LWR Fuel Cycle Options Measured
as Function of Time and Discount Rate (r)*
r = .04
r = .02
1.
Once-Thru
.41
.6
2.
U-Recycle
.28
.28
3.
U- and Pu-Recycle
.45
.45
* 0 signifies most resistant, 1 least resistant.
F.
Bayesian Decision Analysis: Heising's Risk-Benefit Approach to
Quantifying Proliferation Risk in the Nuclear Fuel Cycle
EPRI-sponsored work at Stanford University involved
C. Heising et al.'s
a cost-risk-benefit approach to assessing proliferation risk from a given
fuel cycle. 4 7 The work followed a Bayesian decision analysis approach where
uncertainties on both economic parameters and national security were defined
as probability distributions. The overall proliferation risk of the fuel
cycle inclusive of the impact that plutonium recycle and breeder introduction
in the United States might have on non-weapons states (NWSs) was compared
with the risk already existing from non-commercial routes to nuclear material
attainment. The analysis of diversion resistance was limited to an examination
of the relationship between the number of commercial reprocessors built and
Table
C.3
Correspondence Between Method Attributes
VII
Heising's
I
CHARM
6
7
8
9
10
III
Diversion
SAI
Path (HEDL)
Attributes
3
4
5
II
3
2
4B
4A
--
3
1C
--
2
---
--
1B
--
4
--
5
1
4
1A/B
--
5
2
3B/C
4
5
2
3
--
--
VI V
Silvennoinen Papazoglu et al.
MIT
Finland
1,2
--
4D
4C
3
2
1A
la-c/lb
IV
Selvaduray
Stanford
--
--
6
---
3
4
3A
3A
1
The correspondence shown is approximate as determined from the attribute definitions given in the
papers
Heising's attributes are defined as follows (see Table VI): (3) Capital, O&M Costs, (4) Suitability
for Clandestine Operation, (5) Difficulty of Technical Implementation, (6) No. of Weapons Attainable from Material Flow, (7) Quality of Weapons Material, (8) No. of Technical Personnel Required,
(9) Level of Support Technology and Industry Required, and (10) Time Required to Construct Facility.
7
C- 9
operating in a NWS and the likelihood of a NWS successfully constructing a
weapon. The analysis does not include an examination of success of internationally applied sanctions or timing considerations that impact on
sanctions success. As in the other methods discussed in this-report, the
emphasis lay in establishing quantitative rankings representing the relative
attractiveness of available routes. This was accomplished by defining 10
attributes considered to influence the NWS in making its decision.
(1) Domestic Availability of Technology (compares the present global
distribution of various technical routes; e.g., research reactors are owned
and operated by over 50 countries while no commercial reprocessors are
operating anywhere in the developing world);
(2). Import Availability (compares the relative importability of one
option over another; e.g., research reactors are far easier to import than
are, say, enrichment plants);
(3)
Capital, Operating, and Maintenance Costs;
(4)
Suitability for Clandestine Operation;
(5)
Difficulty of Technical Implementation;
(6)
Number of Weapons Attainable from the Material Flow;
(7)
Quality of Weapons Material;
(8)
Number of Technical Personnel Required;
(9)
Level of Support Technology and Industry Required; and
(10) Time Required to Construct a Facility.
The procedure followed was to make numerical assignments on each key
attribute. The first two attributes (domestic and import availability) were
treated separately because of dependence on the time period examined. The
other seven attributes were compared simultaneously to determine an overall
ranking for each route deemed the "technical attractiveness" factor.
Data on each attribute was extracted from the literature but was qualitative
in nature (e.g., information was often expressed in terms of "high",
Therefore, if the data revealed a "high" cost for a
"medium" or "low").
particular route in comparison to the other alternatives, a rating of
.3 = (1-.7) on a scale of 0 to 1 was assigned to indicate the relative
economic attractiveness of that particular route. Thus, even qualitative
statements made regarding, for example, the degree of organization or
detectability of the operation were placed into quantitative terms through
this assessment procedure (Table C.2.).
Numerical Assignments Associated with
Qualitative Rating
Table C.2.
Qualitative Rating
Very High
High
Medium
Low
Very Low
Numerical Assignment
.9
.7
.5
.3
.1
Table
Final Results:
C,4.
Rankings Placed on Pathways to Weapons Usabe*Material (in.._
Method
Route to*
Material
VII
Heising'
I
CHARM
Method
1
2
3
4
5
6
78
9
22.5
21.7
6.6
4.5
6.6
10.6
9.0
7.0
11.0
7.1-21
10.4-43.5
0
0
2.6-6.3
27-42
5.4-6.9
9.3-34-9
0
II
Diversion
Path (HEDL)
6.1
25.3
1.6
3.6
15.7
15.7
15.7
15.7
.1
III
SAI
D
IV
Selvaduray
Stanford
V
Silvennoinen
Finland
VI
Papazoglu
MIT
18.6
18.9
23.6
23.2'
5.3
2.6
6.6
11.8
9.0
9.0
9.0
20.1-24.7
19.4-23.0
.4
.4
10.9
16.0
11.6
11.6
11.6
f-4
.8-3.0
.05-1.0
5.5-8.0
15.2-20.8
12.0-15.8
14.5-18.9
8.9-11.7
The routes to material are: (1) Research Reactor + Minimum Plutonium Recovery Plant (MPRP), (2) Production
Reactor + MPRP, (3) Power Reactor + MPRP, (4) Power Reactor + Commercial Reprocessor, (5) Diffusion
Cascade, (6) Centrifuge, (7) Aerodynamic Jet, (8) Electromagnetic Separation and (9) Accelerator.
a
ak
C
C-11
Then, for each technological route to weapons usable material, the
numerical assignments for each attribute were summed to arrive at an
overall numerical assignment for the particular technology. This procedure
corresponded to the following equation:
N
Tj
= V
m
.j
n
n
.l1
i
(x
i
E V .j
j=i
where
VTj = total numerical value calculated for route
j;
m
E VTj = sum of total numerical values for each route
j=1
j = 1 to m;
j,
N . = normalized total numerical value for route j,
m
E NT. = 1;
j=1
A. = weight placed on attribute i; in this case
SA. = 1/n (equal weights assumed for each attribute);
V.(x ) = numerical assignment made on attribute i
assuming value x. (high, med, low, etc.).
The value functions Vi(xi) used were based on a linear hypothesis; it
was assumed that the value placed on a "high" outcome for an attribute was
equal to 1 minus the value placed on a "low" outcome - symmetry of values
was assumed. Also, equal weights (Xi) were assumed for each attribute; each
attribute was assumed equally as important as any other - no single attribute
was considered more significant than the others. This was based on the
assumption that, for a particular Nth country, all attributes would be considered equally as important in influencing their final decision regardless
of the decision-making environment they might find themselves in.
G.
A Sample Problem Comparing Methods
To gain further insight into how the various diversion resistance
methods compare, it is useful to examine a sample problem. The problem
examined is taken from the author's thesis in which nine currently available
routes to weapons material were analyzed and compared with respect to their
diversion resistance to obtain indicators of the relative probability that
a non-weapons state would choose one route over another. Using the data
of Table V, it is possible to place all methods on an equal footing to compare
results.
The approach taken is to determine the correspondence between the
eight attributes defined in the author's work and the attributes defined in
the other methods (Table C.3.). Then, the other methods can be applied
Table C.5A
1.
CHARM Method
N
M1 F .
X x* r-1 M
R6ai PD
1D1
la
lb
Mass Flow
of Material
(MT/yr)
M
Pathways
1
2
3
4
5
6
7
8
9
MF ,.
Ms
,
Fraction Divertible w/
or w/o sfgds
le
2
Simple
Device
Mass(MT)
F
1-4
10-20
10-20
30
2-20
2-25
2-20
4-20
1 or less
M
3
Self Pro-. Cost to
tection
Fabricate
Factor (R/hr) Weapon(10 6 $)
S
.
100
100
105
105
1
*1
1
1
105
'
P
4
Time Required to.
Produce
Device (yrs.)
Charm
D
10
10
1000
1000
1000
100
500
100
500
1-3
1-5
2-11
5-11
4-7
3-16
3-16
3-23
3-16
-
X
%
3.3-40x10
2-20x10- 3
7.1-21
10.4-43.5
9-18x10-9
2.7-6 x10- 8
2.9-50x10- 4
1.25-83x10- 3
2.5-133x10- 4
4.3-670x10- 4
.. 25-7x10- 9
-%0
-0
2.6-6.3
27-43
5.4-6.9
9.3-34.9
-0
Notes:
Attribute (la) corresponds to the "Q" factor in the HEDL diversion path method, (lc) to the "Ms" factor and attribute (2)
to the "RHF" (see part II of this appendix). Attribute (2) is rated the same way as for the diversion path method on a
scale from 0.to 1 where 1 represents a very high level of self protection (radiation level v, high). Cost to fabricate
weapon (factor P,'attribute 3 here) is also rated on a scale from 0 to 1 whore a very low cost corresponds to a very high
attractiveness. Also, the time required to produce a weapon is rated on a 0 to I scale as was done in Silvennoinen's and
Heising's work.
MxF - Q in HEDL method.
C-13
consistently to the available data. Final results showing relative rankings
in % of the nine pathways to weapons usable material are given in Table C.4.
Support calculations for this table are found in Tables C.5-C.
These results show a close agreement between the methods of Heising,
Silvennoinen and Papazoglu et al. The Charm and diversion path results
are significantly different but are probably not reliable because they
are based on heuristic methods. Selvaduray's method is more firmly based
on mathematical theory than are either Charm or diversion path methods, but
again is not as firmly based a- are those of Heising, Silvennoinen or
Papazoglu. Note, however, that Selvaduray's results are not much out of
agreement.
An interesting result forthcoming from this exercise is that, given
the validity of the data base, the commercial power reactor - commercial
reprocessor route (#4) consistently is ranked as being very unattractive
to a would-be proliferator, and is far more diversion resistant than
most of the other available routes. The research reactor/production
reactor + MPRP (routes #1 and 2) are consistently indicated to be the more
attractive routes with enrichment routes, particularly the centrifuge
(route #6), being the most attractive.
theory
To conclude, it appears that those methods based on utility
render similar results. Method IV is probably less reliable than V,
VI or VII since, although it bears a close resemblance to utility theory,
it is not a formal application of the theory. Methods I and II must
therefore be viewed very cautiously because they are not based on any confirmed
theoretical process.
I
C-14
Table C.5B
II.-
HEDL Diversion Path Method
I
(1)
TPWF
MAF T DPF x RMF
(2)
-MAF
MTF x NDF x RHF
(3)
DPF -
Q
-
4
mass. of material in fuel cycle, Ms
mass required for single
device
R.G. Pu 30 kg HE U-235 35 kg
W.G. Pu 10 kg
(4)
RMF
Path
1.0
0.75
0.1
Simple Theft
I
Path
1
2
3
4
5
6
7
8
9
Subscitution of Inert Material
Substitution of Isotopic Material
Material
Type
MTF
R.G.Pu W.G.Pu
R.G.Pu~
R.G.Pu
1.0
1.0
1.0
1.0
.8 *
.8
.8
.8
1.0
H.E.U-235
H.E.U-235
H.E.U-235
E.E.U-235
R.G.Pu
MDF
RHF
.8
.8
.8
.8
.8
.8
.8
.8
.8
.7
.7
.1
.1
1.0
1.0
1.0
1.0
.1
(MT/yr) (JMT)
Q
M
.03
.1
.1
.3
.105
.105
.105
.105
.005
.03
.01
.03
.03
.035
.035
.035
.035
.01
DPF
RMF
1
3.2
1.83
3.2
1.73
1.73
1.73
1.73
.71
0.75
1.0
0.75
1.0
1.0
1.0
1.0
1.0
1.0
MAF
.56
.56
.08
.08
.64
.64
.64
.64
.08
TPWF
Z
.43
1.79
.11
.256
1.11
1.11
1.11
1.11
.06
6.1
25.3
1.6
3.6
15.7
15.7
15.7
15.7
.1
4
I - 7.086
(5)
RMF (Removal Mode Factor): Simple theft of material is possible
only in case of commercial reprocessor where Pu is obtainable.
Military
routes require no diversion and therefore are not prone to be detected.
Therefore, we modify the HEDL method here to include a category of
material with the same rating as the simple theft path; that is, the
path wherein material is derived from clandestine military operations
outside of IAEA safeguards.
In routes (l)-(4) and (9) Pu
MDF (Material Description Factor):
(6)
nitrate solutions will need be handled in the PUREX MPRP and commercial
In routes (5)-(8), binary comprnmds, gases, etc., will
reprocessor.
need be handled in the enrichment processes.
(7)
_MTF:
It
is
assumed uranium is
6
enriched to 80% for enrichment routes.
Q is defined as the mass of material that can be diverted without
(8)
detection during one year.
III.
4
61
SAI's Method
SAI's method did not describe a way to convert qualitative/
quantitative data on attributes to quantitative single factors.
Therefore, the SAI method is not applicable to the sample problem.
0
6
C-15
Table C.5C
IV. Selvaduray's Method
Attributes
Covert
Pathways
1
Research
Reactor +
SIndep. U235AJZ?:,2 Location
Pu Streams?
huitability
(Weapons
Material
Clandestinel
Quality)
Operatiorn
Yes
(High Quality)
3 Decont.
Factor
(Opposite
of Radiation
Level
4 Labor
Intansity
(same as Stat.
Of Information)
Rating
5 Effluent
Streams
(No.
(10-r
%
of Weaoons) 1
High
High
V. Low
Few
(8.83)
18.6
1.17
High
High
Med
Several
(9.00)
1.00
18.9
P.FF.?
2
Yes
Produc(Very High
tion
Quality)
Reactor +
.
.
MPRP
?ower
Reactor,
MPRP
No
Low Quality)
( .17)
9.83
LoUr
V. Low
High
Several
Low
V. Low
V. High
Several
.4
4
Commer-
No
cial
Reactor
(Low Quality)
( .17)
9.83
.4
Comm. Reprocessor
5
Diffusion
Cascade
Yes
(Med. Quality)
Low
V. High
High
Several
(5.17)
4.83 10.9
6
Centrifuge
Yes
(Med. Quality)
High
V. High
Med
Several
(7.61)
2.39 16.0
Med
Several
Aerodynamic
Jet
8
Electromagnetic
Separa--.
tion
9
Acceler-
52
4.48
Yes
(Med. Quality)
Low
Yes
(Med. Quality)
Low
V. Low
Med
Several
(5.52) 11.6
4.48
Low
V. Low
Med
Several
(5.52)
(Med.
(Med
Quality)
Q4.48
V.High
11.6
11.6
Z(1-r)-47.51
C~16
V. Silvenncinen et.al's Method (Finland)
xl
Pathways.
1 (C)
V(x 1)
x2
x3
V(X2)
V(X3 )
V.Low Cost
1.00
'~
-
V.Low
.UU
~kS~
4 (C)
C
6 (M)
9 (M)
-
Low
High
High
1.00
.75 -
.75
.75
Low
V.Low
High
V.High
I.UU
Med.
.5
V.High
0.00
Hi.-
.75
V.Low
0.00
V.Low
0.60
1.00
Low
.25
Low
.25
Low
Med.
.5
Med.
.5
0..00
0.00
Low
.25
Low
.25
High
.25
Med.
.5
High
.25
Low
.25
-
Med.
.5
-
V.Low
High
.25
V.High
U.0
8 (M)
V(x 6 )
Med.
.5
V.High
-
-
-
V(X5)
High~
.25
Med.
.5
-
Vi. thg
. (M)
x6
Med.
.5
V.High Cost
0.00
V.High
0.00
/ti~
5 (M)l
X 4)
x5
.'
High.25
High
.25
Hi9
g
.25
V.High
0.00
-
3 (C)
x4
Table C.5D
a
.25
Med.
.5
Med.
.5
Med.
.5
Med.
.5
4
ZXV(X 1)
.
x
.74
23.6
.728
23.2
.165
5.3
.08
2.6
.2075
6.6
.37
11.8
I
.2825
9.0
.2825
9.0
.2825
9.0
*Silvennoinen et al's method characterizes a process by the source material available and
the
material flow rate achievable. Therefore, pathways here are described by source material type
and expected flow rate to be consistent with the uiethod here applied:
(1)
Res Reac + MPRP: Material Flow: R.G. Pu from spent fuel,
flow rate:<< 30MTHM/yr, short cooling time.
(2)
Prod Reac + MPRP: Material -Flow: W.G. Pu from production fuel,
flow rate: up to 30 MTHM/yr, short cooling time
(3)
Pow Reac + MPRP: Material Flow: R.G. Pu from spent
flow rate: up to 30 MHTHM/yr (probably less),
cooling time to reduce radiation hazard (spent fuel assumed diverted
from spent fuel ponds located in NWS that may be as old as 10 yrs.)
(4)
Pow Reac + Com Rep: Material Flow: R.G. Pu from com. PUREX plant
process stream assumed located inside NWS, flow rate: up to
30 MTHM/yr (assumed standard size commercial reprocessor), radiation
level low because of high decontamination factor (4106 for PUREX).
(5)
-(8) Enriehment Plants:
clandestine plant.
(9)
Accelerator:
Raterial Flow:
Material Flow:
W.G.
Eigh Enriched U-235 passed through
Pu; flowrate:
up to 30kg Puf produced per year.
The authors define two sets of weights, one for civilian(C) routes and
other for military(M). X is assessed for M but not for C; X is assessed
for C but not for M:
15
Unsep. R.G. Pu.
X4
X3
X2
X
Pu
C
M
.11
-
-
.20
.15
.10
.17
-
.30
-
.
9
.35
The ratings are based on a 0 to 1 scale where 0 means the value to the
non-weapons state if a path is least attractive and 1 most attractive:.
0
.25
V. Low Attractiveness
"
Low
.5
Med
.75
1
High
V.High
"
it
Table C.5E
M. EapM-olju et. al.'s Method
3
Inherent Difficulity
Covert Pathways
Research Reactor
Development
Time (Yrs.)
Warning Period
(2)
Status of
Information
Radiation
Level (R/Hr
Criticality
Weapons
Material
Quality
Development
Cost
6
(10 $)
High
R.G.Pu
10
Low
V. High
W.G.Pu
10
105
High
Low
R.G.Pu
1000
1(3,3)
10
High
Low
R.G.Pu
0 00
11(2,3)
0
High
Med
HEU-235
1000
Med
HEU-2 5'
100
1-3
< 10
1-5
< 5
E(2,2)
10
2-11
,15
F(2,3)
> 50
30
'A(1,1)
10
2
Low
AM
2
Production
Reactor + MPRP
3
Power Reactor
+
4
Power Reactor
2
5-11
+
Commercial Rep.
5
Diffusion'
Cascade
6
Centrifuge
7
Aerodynamic
Jet
4-7
15
3-16
25-50
8
Electro Magnetic
Separation
3
Accelerator
25-50
C- Crisis Environment
NC- Non- Crisis Environment
> 30
> 50
30
-
E(2,2)
E(2,2)
0
0
E(2,2)
0
E(2,2)
105
Med
High
High
Mod
Med
1EU-235
500
IN-235
100
EU-235
500
Table C.5F
VI.
Papazoxlu et.al.'s Method
Attribute
:
1
Results of Papazoglu's Method:
2
3a
3b
Normalized Results In Right-Hand Column
3c
4
5
0
r
10 (1+E)
Normalized
(1) C -17- -28
NC -05- -1
-. 03
-. 07
'0
-. 026
-. 026
0
0
0
0
0
--226--336
-.146- -:196
.774-.664
.854-.804
6.64-7.74
8.04-8.54
.19-20.8
.247-20.1
(2) C .17- -3
NC-.05- -12
-. 02
-.04
-. 06
-.06
-. 026
-.026
0
0
0
0
0
0
-.276- 406
-.176- -246
.724-.594
.824-.754
5.94-7.24
7.54-8.24
.*T3-. 05'
.23-.194
(3) C -.25- -:31
NC -. 08- -. 13
-.04- .07
-.09- .15
-.35
-.36
-.154
-.154
-.04
-.04
-.01
-. 03
-.04
-.11
-.884--.97
-.864- 974
.116-.03
.136-.026
.3-1.16
.26-1.36
.009-.03
.008-.03
(4) C r31
NC -.12- -. 13
-.07
-.15
-.38
-.38
-.154
-.154
-.04
-.04
-.01
-.03
-.04
.. 11
-1
-.984-7994
0
-.
016-.006
0
.16-.06
0 - 0
.005-.001
(5) C -.31
NC -11- -.
13
-.06- -.
07
-.13- -.
15
-.32
-.32
0
0
-.04
-.04
-.005
-.015
-.04
-.11
-.775- 7785
-.725--.765
..
225-.215
.275-.235
2.25-2.15
2.75-2.35
.07-.06
.08-.055
(6) C ,28- -:31
NC 71 - -13
-.095
-.098
-.06
-.06
0
0
-.02
-.02
-.005
-.015
0
-.02
.46-749
-.323--353
.54-.51
.677-.647
5.4-5.1
6.77-6.47
.157-.137
.208-.152
(7)
C-:31
NC-,13
-.06
-.13
-.06
-.06
0
0
.-.04
-.04
-.005
-.015
-.04
-.11
-.515
-.485
.485
.5 5
4.85
5.15
.14-.13
.158-.12
(8)
C -28
NC '-1
-.07
-.15
-.06
-.06
0
0
-.04
-.04
-.005
-.015
0
-.02
-.455
-.385
.545
-.615
5.45
6.15
(9) C -r31
NC 713
-.06
-.13
-.06
-.06
-.02
-.02
-.005
-.015
-.04
-.11
-. 649
-.619
Cc-Crisis Environment
NC-Non-Crisis Environment
0
W.154
-. 154
.351
.381
3.51
3.81
4159-.147
.189-.145
.102-.094
.117-.089
Table C.5G
VII. Heising's Method Applied to Problem Expressed with Papazoglu et. al.'s Attribute Definitions
1
3
2
4
5
Inherent Difficulty
Covert
Pathways
Research
Reactor +
MPRP
2
Production
Reactor +
Weapons
Materia:
Development
Information
Radiation
Level
V. High
.9
Low
.7
Low
.
V. Low
.9
Med.
.5
Low
.7
Low
.7
Med
.5
V.Low-Low
.2
V. High
.1
High
.1
Low
.3
V. High
.1
V. Low
.1
V. High
.1
High
.1
Low
.3
High
.3
High
.3
Low
.3
High
.1
Med.
.5
V. High
.1
V. High
Me4.
Med.
Med.
Med.
Med.
.5
.5
.5
.5
High
.1
Development
Time
V. Low
.9
Status of
Warnino Period
Low
.7
Low
.7
Criticalih
Quality
.$'
I. yg
F:1
Cost
Normal
-ized
High
.7
V. Low
.9
5.5
.225
V. High
.9
V. Low
.9
5.3
.217
V.14;
.j
1.6
.066
1.1
.045
1.6
.066
.5
2.6
.106
Med.
.5
High
.3
2.2
.09
1.8
.07
2.7
.11
MPRP
3
Power Reactor +
High
.3
.
MPRP
4
Power Reactor +
High
.3
V. High
.1
Commercial
Rep roc4AAer_______
5
Diffusion
Cascade
6
Centifuge
.1
-Na-
7
Aerodynamic
Jet
Mt
-5
High
Med.
.5
-na-
V. High
.1
Med.
.5
-na-
High
.1
Med.
.5
Med.
.5
High
Hed.
V. High
Med.
Med.
High
.3
.5
.5
.5
.3
8
Electro
Magnetic
Separation
V. High
.1
9
Accelerator Med.
.5
.1
.3
0
2
.7
.'~4
k'..
'A
At..
I
6
C