BACKUP SLIDES
FNST Issues, Development, and Role of
Next Step Fusion Nuclear Facility FNF
(VNS/CTF/FDF, etc.) and ITER TBM
Mohamed Abdou
FNST Meeting, UCLA August 12-14, 2008
1
Quantification of Test Requirements
General Observations of FINESSE Study Results
• In many cases, a true integrated test in the strictest sense cannot be performed
under significantly scaled-down conditions for certain parameters (e.g., power
density, surface heat load, geometry)
• Under scaled-down environmental conditions, the function of an integrated test
module has to be divided into two or more “act-alike” tests. Each act-alike test
emphasizes a group of issues/phenomena.
• While an overlap among the various act-alike tests can be included to account
for certain interfaces, a concern about possibly missing some phenomena
remains.
• Perfect quantitative engineering scaling is not possible because it requires
complete quantitative models for all (including interactive) phenomena.
• If fusion testing will have to be carried out under scaled-down conditions, then:
- Engineering scaling needs to continue to be nourished as a key technical
discipline in fusion.
- The need for a more thorough understanding of phenomena and more
analytical modeling will become more critical.
2
How Many Modules/Submodules Need to Be Tested For Any
Given One Blanket Concept?
•
•
Never assume one module, because engineering science for testing shows
the need to account for:
1. Engineering Scaling
2. Statistics
3. Variations required to test operational limits and
design/configuration/material options
US detailed analysis indicates that a prudent medium risk
approach is to test the following test articles for any given One Blanket
Concept:
- One Look-Alike Test Module
- Two Act-Alike Test Modules
- (Engineering Scaling laws show that at least two modules are required,
with each module simulating a group of phenomena)
- Four supporting submodules (two supporting submodules
for each act-alike module to help understand/analyze test
results)
- Two variation submodules (material/configuration/design variations and
operation limits)
These requirements are based on “functional” and engineering
scaling requirements. There are other more demanding
requirements for “Reliability Growth” (See separate section on this)
3
Neutron Wall Load Requirements
Importance
• Neutron wall load is a primary source of both heating and nuclear
reactions in the blanket
–
–
–
–
Bulking heating
Surface heating
Reaction rate (e.g., tritium production)
Fluence
Neutron wall load requirements determined by:
• Engineering scaling requirements (conclusion: should not scale down by
more than a factor of 2-3
• Tradeoffs between device availability and wall load for a given testing
fluence and testing time
Wall Load and Availability Required to Reach 6 MW•y/m2
Goal Fluence in 12 Calendar Years
Wall Load (MW/m2)
Availability
1
1.5
2
2.5
50%
33%
25%
20%
For pulsed plasma operation, this becomes the product of availability and plasma duty cycle. Therefore,
4
at any given wall load, higher availability would be required.
Importance of Steady State Operation for
Nuclear Testing
• To substantially increase the capability for
meaningful nuclear technology testing
• To reduce the failure rate and improve the
availability of the testing device
- Many papers and presentations on this topic from
the last 20 years. It is well understood and accepted
(see, for example, www.fusion.ucla.edu/abdou)
5
Effects of Pulsed Plasma Operation on
Nuclear Technology Testing
• Time-Dependent Changes in Environmental Conditions for Testing
–
–
–
–
Nuclear (volumetric) heating
Surface heating
Poloidal magnetic field
Tritium production rate
• Result in Time-Dependent Changes and Effects in Response of Test
Elements that:
– Can be more dominant than the steady-state effects for which testing is
desired
– Can complicate tests and make results difficult to model and understand
Examples of Effects
–
–
–
–
Thermal conditions
Tritium concentration profiles
Failure modes/fracture mechanism
Time to reach equilibrium
6
COT Requirements
•
Test Schedule Issues
– It is desirable to complete a test campaign before the machine is shut
down for a significant period of time
– The objective of design/test/fix iterative program requires timely data
acquisition as input to redesign and construction of new test
modules. It is therefore desirable to complete test campaigns as
quickly as possible.
•
Requirements on Environmental Control
– The level of control over conditions within test modules and ancillary
systems during shutdown is uncertain.
Recommended COT for FNT:
 1-2 weeks
7
Device Fluence vs Test Module Fluence
• Must make a distinction between:
- Fluence achievable at test module ( modules will fail and will be
replaced. Module Fluence is the “cumulative” experience
accumulated on successive test articles, in “reliability growth”
terminology)
- Test facility “lifetime fluence” (The device itself will need to have a
longer lifetime than the test articles. The blanket is an exception
because it is the “object of testing”, depending on testing strategy)
• Benefits to FNT testing as a function of neutron fluence have been
recognized:
- Many issues show continuous increase in benefits at higher fluences
- Some issues show distinct fluence regions of highest benefit
• There is inevitably a long period of fail/replace/fix for test modules
• Time required to perform the three testing stages: The reliability
growth testing phase is the most demanding on fluence
requirements.
8
Testing Fluence
• In this study, we derive fluence directly for each of the three stages of
fusion testing
Stage I: Scoping (~ 0.1 - 0.3 MW • y/m2)
Just enough time to explore environment, develop instrumentation, and get
initial data
Stage II: Concept Verification (1-3 MW • y/m2)
1 MW • y/m2 is barely enough to establish engineering feasibility (~10% of
minimum life)
Stage III: Engineering Development & Reliability Growth (4-6 MW • y/m2)
This fluence is derived from detailed analysis of reliability growth testing
9
“Reliability Growth”
Upper statistical confidence level as a function of test time in
multiples of MTBF for time terminated reliability tests (Poisson
distribution). Results are given for different numbers of failures.
1.0
Number of Failures 0
Confidence Level
0.8
TYPICAL
TEST
SCENARIO
Example,
1
To get 80% confidence
in achieving a particular
value for MTBF, the
total test time needed
is about 3 MTBF (for
case with only one
failure occurring during
the test).
2
0.6
3
0.4
4
0.2
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Test Time in Multiplies of Mean-Time-Betw een-Failure (MTBF)
Reference: M. Abdou et. al., "FINESSE: A Study of the Issues, Experiments and Facilities for Fusion Nuclear
Technology Research & Development, Chapter 15 (Figure 15.2-2.) Reliability Development Testing Impact on Fusion
Reactor Availability", Interim Report, Vol. IV, PPG-821, UCLA,1984. It originated from A. Coppola, "Bayesian
Reliability Tests are Practical", RADC-TR-81-106, July 1981.
10
Achievable DEMO and Blanket System Availabilities
(for a given confidence level) depend on:
• Testing Fluence at the Blanket Test Module
• Number of test modules
• Achievable Mean Time to Replace (MTTR) for Blankets
11
Findings of Testing Fluence Requirements on
Achievable Reactor Availability Analyses
• Achieving a “ cumulative” fluence of ~ 5-6 MW • y/m2 at the test
modules with ~ 6-12 test modules is crucial to achieving DEMO
reactor availability on the 40% to 50% range with 90% confidence,
• Achieving DEMO reactor availability of 60% with 90% confidence may
not be possible for any practical blanket test program,
• The mean downtime (MTTR) to recover (or replace) from a random
failure in the blanket must be on the order of one week or less in order
to achieve the required blanket and reactor system availabilities, and
• Determining (and shortening) the length of the MTTR (how long it
takes to replace a failed blanket module) must be by itself one of
the critical objectives for testing in fusion facilities (e.g. in CTF).
12
Obtainable Blanket System Availability (%)
Obtainable Blanket System Availability with 50%
Confidence for Different Testing Fluences and Test Areas
MTTR = 1 month
1 failure during the test
80 blanket modules in
blanket system
70
60
6 MW.yr/m2
Experience factor =0.8
3 MW.yr/m2
50
40
30
1 MW.yr/m2
20
Neutron wall load = 2 MW/m2
10
0
0
2
4
6
Test Area (m2)
8
10
Level of Confidence based on Figure 15-2.2 in "FINESSE: A Study of the Issues, experiments and Facilities for Fusion Nuclear
13
Technology Research & Development, Chapter 15 Reliability Development Testing Impact on Fusion Reactor Availability", Interim
report, Vol. IV, PPG-821, UCLA, 1984.
Device Surface Area Requirements
• No. of Modules per Specific Design Concept
– Need for Engineering Scaling and Statistics.
– A large number of test modules lead to a faster reliability growth and a higher
precision level.
• Full scale test preferable
– There are many problems that were solved only after setting up a full scale test.
– There are also many problems that surfaced only in the full scale test but did not
show in the reduced scale.
– Account for neutron flux spatial variation in poloidal direction.
• If each module first wall area is about 1 m2
– Test area required = (6 – 12) x A (for engineering scaling) m2 per concept.
• If test 3 concepts, use 6 modules per concept; or 2 concepts use 12 modules
per concept.
Total test area at the first wall required: > 10 m2
14
Level of Confidence Obtainable for
Different Testing Scenarios
Test Area
(m2)
0.5
1
5
10
# of Test Articles
1
2
10
20
Test Fluences =
1 MWyr/m2
0 failure
1 failure
during the
during the
test
test
1.5%
~0%
3.6%
~0%
10.9%
0.7%
17.8%
1.7%
Test Fluences =
3 MWyr/m2
0 failure
1 failure
during the
during the
test
test
5%
~0%
9.5%
0.5%
30%
5.5%
47%
14%
Test Fluences =
6 MWyr/m2
0 failure
1 failure
during the
during the
test
test
10%
0.5%
17%
1.5%
51.5%
16%
72%
36%
Neutron wall load = 2 MW/m2
MTBF per module = 26 years
Experience factor = 0.8
(*test fluence of 0.1 MWyr/m2 is too low to consider)
Note
1) Assuming that the reactor has 16 sectors, 80 blanket modules (each module is about 1(toroidal) x 8 (poloida) m2).
“Engineering scaling” is applied to the test article design in order to have meaningful data extrapolated from a 0.5 m2
2) The irradiation effects on material properties are not considered in the estimation.
3) Level of Confidence based on Figure 15-2.2 in "FINESSE: A Study of the Issues, experiments and Facilities for Fusion
Nuclear Technology Research & Development, Chapter 15 Reliability Development Testing Impact on Fusion Reactor
Availability", Interim report, Vol. IV, PPG-821, UCLA, 1984.
15
Reliability/Availability is a challenge to fusion, particularly
FW/blanket, development
• Fusion System has many major
components (TFC, PFC, plasma
heating, vacuum vessel, blanket,
divertor, tritium system, fueling,
etc.)
 All components except the reactor
core (FW/blanket) will have
reliability data from ITER and other
facilities
 The reliability requirements on the
FW/Blanket are most challenging
and pose critical concerns (due to a
large number of modules). These
must be seriously addressed as an
integral part of the R&D pathway to
DEMO.
 Predicting Achievable MTBF
(mean-time-between-failure)
requires real data from integrated
tests in the fusion environment.
CTF base machine avaialbility =30% (MTTR blanket = 2 weeks)
Demo base machine availability =30% (MTTR blanket = 2 weeks)
Demo base machine availability 50% (MTTR blanket = 2 weeks)
Demo base machince availability 50% (MTTR blanket= 1 week)
0.4
The base machine includes 10 major components.
CTF FW area 100 m2 with 64 blanket modules
Demo (ITER like FW area 680 m2 and 440
blanket modules)
0.35
Availability decreases
due to the number of
module increases
0.3
1
0.25
2
0.2
1
0.15
Availability increases due to
improved base machine
availability
3 Availability increases due to a
shortened MTTR for blanket
2
0.1
0.05
0
Lifetime of Demo FW/blanket
3
 10 years
2
4
6
Blanket Module MTBF (year)
8
16 10
Reliability/Availability is a challenge to fusion,
particularly blanket/PFC, development
• Fusion System has many major components (TFC, PFC, plasma heating,
vacuum vessel, blanket, divertor, tritium system, fueling, etc.)
- Each component is required to have high availability
• All systems except the reactor core (blanket/PFC) will have reliability data
from ITER and other facilities
• There is NO data for blanket/PFC (we do not even know if any present blanket
concept is feasible)
• Estimates using available data from fission and aerospace for unit failure rates
and using the surface area of a tokamak show:
PROBABLE MTBF for Blanket ~ 0.01 to 0.2 yr
compared to REQUIRED MTBF of many years
Need Aggressive “Reliability Growth” Program
We must have an aggressive “reliability growth” program for the
blanket / PFC (beyond demonstrating engineering feasibility)
1) All new technologies go through a reliability growth program
2) Must be “aggressive” because extrapolation from other technologies
(e.g. fission) strongly indicates we have a serious CHALLENGE
17
Conclusions on Blanket and PFC Reliability Growth
• Blanket and PFC tests in ITER alone cannot demonstrate DEMO
availability higher than 4%
• Blanket and PFC testing in VNS (CTF) allows DEMO blanket system
and PFC system availability of > 50%, corresponding to DEMO
availability > 30%
Recommendations on Availability/Reliability Growth Strategy and Goals
- Set availability goal for initial operation of DEMO of ~ 30% (i.e. defer some risk)
- Operate CTF and ITER in parallel, together with other facilities, as
aggressively as possible
- Realize that there is a serious decision point with serious consequences
based on results from ITER and CTF
• If results are positive proceed with DEMO
• If not, then we have to go back to the drawing board
18
Demo Definition
Previous US system and planning studies and the FESAC Plan for
Development of Fusion Energy in 2003 identified general goals and features of
DEMO. Below are relevant quotes from the FESAC 2003 Plan:
• The goal of the plan is operation of a US demonstration power plant (Demo),
which will enable the commercialization of fusion energy. The target date is
about 35 years. Early in its operation the Demo will show net electric power
production, and ultimately it will demonstrate the commercial practicality of
fusion power. It is anticipated that several such fusion demonstration devices
will be built around the world. In order for a future US fusion industry to be
competitive, the US Demo must:
a) be safe and environmentally attractive,
b) extrapolate to competitive cost for electricity in the US market, as well as for
other applications of fusion power such as hydrogen production,
c) use the same physics and technology as the first generation of competitive
commercial power plants to follow, and
d) ultimately achieve availability of ~ 50%, and extrapolate to commercially
practical levels.
19
Demo Performance Parameters
and Characteristics
Value
Neutron Wall Loading (average)
2-3 MW/m2
Tritium Fuel Cycle
self-sufficient
Plasma Mode of Operation
steady state
Demo Ultimate Availability Goal
~ 50%
Thermal Conversion Efficiency
> 30%
Overall Plant Lifetime (Design)
30 years
Blanket Lifetime
10-20 MW.y/m2
20
Comparison of Key Blanket Testing Parameters
Parameter or Feature
DEMO
(Typical)
Testing Requirements
(derived in fusion
literature)
ITER
(Feat)
Neutron Wall Load, MW/m2
2 to 4
1 to 2
0.55
Plasma Mode of Operation
Steady State
(or long pulses)
Steady State
Highly pulsed
~1
>0.8
0.25
>10,000
<100
>1000
<100
400
1200
Minimum COT (period of 100 %
availability), weeks
many
1 to 2
??
Neutron Fluence, MW.y/m2
7-20
4 to 6
0.1
>10
~7
Plasma Duty Cycle*
Plasma Burn Time, s
Plasma Dwell Time, s
Total Test Area, m 2
*Plasma duty cycle = burn time/(burn time + dwell time)
21
Table XX.*
Characteristic
Time Constants
in Solid Breeder
Blankets
* From Fusion Technology, Vol. 29,
pp 1-57, January 1996
Process
Flow
Solid breeder purge residence time
Coolant residence time
Thermal
Structure conduction (5-mm metallic alloys)
Structure bulk temperature rise
5 mm austenitic steel / water coolant
5 mm ferritic steel / helium coolant
Solid breeder conduction
Li2O (400 to 800ºC)
10 MW/m3
1 MW/m3
LiAlO2 (300 to 1000ºC)
10 MW/m3
1 MW/m3
Solid breeder bulk temperature rise
Li2O (400 to 800ºC)
10 MW/m3
1 MW/m3
LiAlO2 (300 to 1000ºC)
10 MW/m3
1 MW/m3
Tritium
Diffusion through steel
300ºC
500ºC
Release in the breeder
Li2O
400 to 800ºC
LiAlO2 300 to 1000ºC
Time Constant
6s
1 to 5 s
1 to 2 s
~1 s
5 to 10 s
30 to 100 s
300 to 900 s
20 to 100 s
180 to 700 s
30 to 70 s
80 to 220 s
10 to 30 s
40 to 100 s
150 days
10 days
1 to 2 h
20 to 30 h
22
Table XXI.*
Characteristic Time
Constants in LiquidMetal Breeder
Blankets
Process
Flow
Coolant residence time
First wall (V=1 m/s)
Back of blanket (V=1 cm/s)
Thermal
Structure conduction (metallic alloys,
5mm)
Structure bulk temperature rise
Liquid breeder conduction
Lithium
Blanket front
Blanket back
LiPb
Blanket front
Blanket back
Corrosion
Dissolution of iron in lithium
* From Fusion Technology, Vol. 29,
pp 1-57, January 1996
Tritium
Release in the breeder
Lithium
LiPb
Diffusion through:
Ferritic Steel
300ºC
500ºC
Vanadium
500ºC
700ºC
Time Constant
~30 s
~100 s
1 to 2 s
~4 s
1s
20 s
4s
300 s
40 days
30 days
30 min
2230 days
62 days
47 min
41 min 23
List of Journal Papers & Reports
(examples only)
1.
2.
3.
4.
5.
6.
7.
8.
Abdou, M. “ITER Test Program: Key Technical Aspects,” Fusion
Technology 19(May 1991) 1439+
Gierszewski, P., Abdou, M., Bell, et al. “Engineering Scaling and
Quantification of the Test Requirements for Fusion Nuclear Technology,”
Fusion Technology 8 (July 1985) 1100
Abdou, M., et al. “A Study of the Issues and Experiments for Fusion
Nuclear Technology,” Fusion Technology 8 (1985) 2595
Abdou, M., et al. “Technical Issues and Requirements of Experiments and
Facilities for Fusion Nuclear Technology,” Nuclear Fusion 27 (1987) 4,
619
Abdou, M., Berk, S., Ying, A., et al. “Results of an International Study on
a High-Volume Plasma-Based Neutron Source for Fusion Blanket
Development,” Fusion Technology 29 (1996) 1-57
“Test Program Summary,” ITER-IL-NE-3-0-5, ITER Document, February
1990
“Test Program Summary,” ITER-IL-NE-3-9-4, ITER Document, July
1989
There are numerous topical reports from INTOR, ITER-CDA and ITEREDA. Contact M. Abdou for copies of the US reports (1980-1997)
24
Current physics and technology concepts lead to a
“narrow window” for attaining Tritium self-sufficiency
Required TBR
td = doubling time
td=1 yr
td=5 yr
Fusion power
1.5GW
Reserve time
2 days
Waste removal efficiency 0.9
(See paper for details)
Max achievable
TBR ≤ 1.15
td=10 yr
“Window” for
Tritium self
sufficiency
Fractional burn-up [%]
25
Serious Engineering Design of a breeding blanket (in particular real structural
engineering design is lacking): Potential for tritium self sufficiency is
uncertain. (Is DT fusion feasible?)
−The only serious engineering design in ITER (for non-breeding blanket)
shows a need for a thick first wall??!).
10 mm
22 mm
Plasma
49 mm
ITER First Wall Panel Cross Section
Coolant
channel
−Thick first walls (>1cm) seriously threaten the ability to attain
tritium self sufficiency, hence the feasibility of DT fusion
−Real Engineering Design of breeding blankets is needed as
part of evaluating blanket options
Units: mm
EU-First wall design
26
Tritium Consumption in ITER
 Here is from a summary of the final design report.
Link is:
http://fusion.gat.com/iter/iter-ga/images/pdfs/cost_estimates.pdf
 9.4.3 Fuel Costs
The ITER plant must be operated, taking into account the available
tritium externally supplied. The net tritium consumption is 0.4
g/plasma pulse at 500 MW burn with a flat top of 400 s
 “The total tritium received on site during the first 10 years of
operation, amounts to 6.7 kg.”
 “whereas the total consumption of tritium during the plant life time
may be up to 16 kg to provide a fluence of 0.3 MWa/m2 in average
on the first wall”
 “This corresponds, due to tritium decay, to a purchase of about 17.5
kg of tritium. This will be well within, for instance, the available
Canadian reserves.”
27
Separate Devices for Burning Plasma and FNT Development, i.e.
ITER + CTF are more Cost Effective and Faster than a Single
Combined Device
(to change ITER design to satisfy FNT testing requirements is very
expensive and not practical. To do it in “DEMO” is impossible)
NWL
Fusion
Power
Fluence
(MW·y/m2)
Tritium
Consumption
(TBR = 0)
Tritium
Consumption
(TBR = 0.6)
0.55
500 MW
0.1
5 kg
2 kg
2) FNT Testing (CTF)
>1
< 100 MW
>6
33 kg
13 kg
Single Device Scenario
(Combined Burning Plasma +
FNT Testing), e.g. ITER with
major modifications (double the
capital cost)
>1
910 MW
>6
>305 kg
>122 kg
Two Device Scenario
1) Burning Plasma (ITER)
FACTS
- World Maximum Tritium Supply (mainly CANDU) available for Fusion is 27 kg
- Tritium decays at 5.47% per year
- Tritium cost now is $30M / kg. More tritium will cost $200M / kg.
Conclusion:
- There is no external tritium supply to do FNT testing development in a large power
DT fusion device. FNT development must be in a small fusion power device.
28
Projected Ontario (OPG) Tritium Inventory (kg)
Projections for World Tritium Supply Available to Fusion
for Various Scenarios (Willms, et al.)
30
CTF
5 yr, 100 MW, 20% Avail, TBR 0.6
5 yr, 120 MW, 30% Avail, TBR 1.15
10 yr, 150 MW, 30% Avail, TBR 1.3
25
20
Candu Supply
w/o Fusion
15
1000 MW Fusion,
10% Avail, TBR 0.0
ITER-FEAT (2004
start) + CTF
10
5
0
1995
ITER-FEAT
(2004 start)
See calculation assumptions in
Table S/Z
2000
2005
2010
2015
2020
Year
2025
2030
2035
2040
2045
• World Tritium Supply would be Exhausted by 2025 if ITER were to run at 1000 MW fusion power with 10% availability
• There is no external tritium supply to do FNT testing development in a large power DT fusion
device. FNT development must be in a small fusion power device.
• We need 5-10 kg of tritium as “start-up” inventory for DEMO (can be provided from CTF operating with
TBR > 1 at later stage of operation)
• Blanket/PFC must be developed in the near term prior to DEMO (and we cannot wait
29
very long for blanket/PFC development even if we want to delay DEMO).
Table S/Z
(data used in Fig. for Tritium Supply and Consumption Calculations)
Tritium Supply Calculation Assumptions:
• Ontario Power Generation (OPG) has seven of twenty CANDU reactors idled
• Reactors licensed for 40 years
• 15 kg tritium in 1999
• 1999 tritium recovery rate was 2.1 kg/yr
• Tritium recovery rate will decrease to 1.7 kg/yr in 2005 and remain at this level until 2025
• After 2025 reactors will reach their end-of-life and the tritium recovery rate will decrease
rapidly
• OPG sells 0.1 kg/yr to non-ITER/VNS users
• Tritium decays at 5.47 % / yr
It is assumed that the following will NOT happen:
• Extending CANDU lifetime to 60 years
• Restarting idle CANDU’s
• Processing moderator from non-OPG CANDU’s (Quebec, New Brunswick)
• Building more CANDU’s
• Irradiating Li targets in commercial reactors (including CANDU’s)
• Obtaining tritium from weapons programs of “nuclear superpowers”
• Premature shutdown of CANDU reactors
30
Table S/Z (cont’d)
(data used in Fig. for Tritium Supply and Consumption Calculations cont’d)
ITER-FEAT Assumptions:
• Construction starts in 2004 and lasts 10 years
• There are four years of non-tritium operation
• This is followed by 16 years of tritium operation. The first five years
use tritium at a linearly increasing rate reaching 1.08 kg T used per
year in the fifth year. Tritium usage remains at this level for the
remainder of tritium operations.
• There is no tritium breeding (TBR=0)
• There is no additional tritium needed to fill materials and systems
CTF Assumptions:
• Begins burning tritium in 2017
• 5 yr, 100 MW, 20% availability, TBR 0.6
• 5 yr, 120 MW, 30% availability, TBR 1.15
• 10 yr, 150 MW, 30% availability, TBR 1.3
31
ITER Impact on Canadian/Korean Candu Tritium Inventory (March 2007)
(from Scott Willms, LANL)
•
Following the methodology developed for the Snowmass and 35-year fusion development plan exercises, the impact
of ITER (the seven party agreement signed 11/07) on tritium available from both Canada and Korea was analyzed.
•
The assumptions were:
–
–
–
–
–
–
–
–
–
–
–
–
•
The results on the following figure show:
–
–
–
•
Use the same assumption for Canadian tritium as was used for the 35-yr development plan
In addition to the Canadian tritium, Korean tritium is available for fusion (about a 25% additional amount of tritium)
ITER has a 2 kg tritium working inventory which is built up over two years beginning in 2018
ITER first plasma is 2016 with 3 yr HH, 1 yr DD following by tritium operations
ITER tritium operations are 6 yr followed by 1 year maintenance (no tritium burned) followed by 10 year tritium
The first 10 year campaign includes three yr HH, 1 yr DD and then builds to 1.08 kg tritium burned per year over a five year period,
then remains flat to the end of the first 10 years (modification of scenario communicated by Janeschitz at Snowmass 2002)
The second 10 years burns 1.43 kg tritium per year for each of the 10 years. This builds the wall irradiation to 0.3 MW-yr/m2
(neutrons) average over a 680 m2 wall
Between the two 10-yr campaigns there is a one year maintenance phase which presumably includes a first wall replacement. The
first 10 year would not irradiate the first wall to 0.3 MW-yr/m2. The new first wall installed at the beginning of the second 10-yr
increases from 0 to 0.3 MW-yr/m2 linearly over the second 10 yr.
At the end of ITER a total of 1 kg of tritium is lost to waste and 1 kg of tritium is returned to Canada/Korea
The only demand on the Canadian/Korean tritium is 0.1 kg/yr for sales and ITER. That is, there is no accounting for other demands
on this tritium such as CTF or Demo.
There is no tritium breeding in ITER
Note: There has been no signaling from Korea that they will supply tritium to ITER. They are only recovering tritium to get it out of
their heavy water. Canada assisted Korea with the installation of their tritium recovery system, and it is not known what contractual
agreements they may have. Korean tritium sales, if they took place, would be in competition with Canada.
Upper Curve: The Canadian/Korean tritium inventory without fusion. This assumes the only demand on this tritium is decay and 0.1
kg/yr sales.
Middle Curve: The Canadian/Korean tritium inventory with the above + ITER
Lower Curve: The yearly ITER transactions with the Canadian/Korean tritium due to ITER tritium inventory build up (down) + decay +
burn
Observations:
– With these assumptions there is enough tritium for ITER, and about 5 kg of tritium would remain at the end of ITER
– The tritium supply would not accommodate any significant extension of ITER, loss of tritium or significant fusion
experiment requiring tritium
– There is a marginal amount of tritium remaining to startup one Demo, and tritium breeding on that one machine would
have to work “out of the box”
32
Blanket systems are complex and have many
integrated functions, materials, and interfaces
[18-54] mm/s
[0.5-1.5] mm/s
Neutron Multiplier
Be, Be12Ti (<2mm)
Tritium Breeder
Li2TiO3 (<2mm)
PbLi flow
scheme
First Wall
(RAFS, F82H)
Surface Heat Flux
Neutron Wall Load
33
Fusion environment is unique and complex:
multi-component fields with gradients

Neutrons (fluence, spectrum, temporal and

spatial gradients)
• Radiation Effects (at relevant temperatures, 
stresses, loading conditions)
• Bulk Heating
• Tritium Production
• Activation

Heat Sources (magnitude, gradient)
•
•

Bulk (from neutrons and gammas)
Surface
Synergistic Effects
•
•

Particle Flux (energy and density,
gradients)
Magnetic Field (3-component with
gradients)
• Steady Field
• Time-Varying Field
Mechanical Forces
• Normal/Off-Normal

Thermal/Chemical/Mechanical/
Electrical/Magnetic Interactions
Combined environmental loading conditions
Interactions among physical elements of components
Multi-function blanket in multi-component field environment leads to:
- Multi-Physics, Multi-Scale Phenomena
Rich Science to Study
- Synergistic effects that cannot be anticipated from simulations & separate effects
tests.
A true fusion environment is ESSENTIAL to activate mechanisms that
cause prototypical coupled phenomena and integrated behavior
34
Fusion “Break-in” & Scientific Exploration
Stage I
0.1 – 0.3 MW-y/m2,

0.5 MW/m2, burn > 200 s
Sub-Modules/Modules
 Initial exploration of coupled phenomena in a fusion environment
 Uncover unexpected synergistic effects, Calibrate non-fusion tests
 Impact of rapid property changes in early life
 Integrated environmental data for model improvement and
simulation benchmarking
 Develop experimental techniques and test instrumentation
 Screen and narrow the many material combinations, design
choices, and blanket design concepts
See Neil Morley’s presentation on Fusion Blanket Phenomena and Timescales
35
Engineering Feasibility & Performance
Verification
Stage II
1 - 3 MW-y/m2, 1-2 MW/m2, steady state or long pulse, COT ~ 1-2 weeks
Modules
 Uncover unexpected synergistic effects coupled to radiation
interactions in materials, interfaces, and configurations
 Verify performance beyond beginning of life and until changes in
properties become small (changes are substantial up to ~ 1-2
MW · y/m2)
 Initial data on failure modes & effects
 Establish engineering feasibility of blankets (satisfy basic
functions & performance, up to 10 to 20 % of lifetime)
 Select 2 or 3 concepts for further development
36
Component Engineering Development &
Reliability Growth
Stage III
> 4 - 6 MW-y/m2, 1-2 MW/m2, steady state or long burn, COT ~ 1-2 weeks
Modules/Sectors
 Identify lifetime limiting failure modes and effects based on full
environment coupled interactions
 Failure rate data: Develop a data base sufficient to predict meantime-between-failure with confidence
 Iterative design / test / fail / analyze / improve programs aimed at
reliability growth and safety
 Obtain data to predict mean-time-to-replace (MTTR) for both
planned outage and random failure
 Develop a database to predict overall availability of FNT
components in DEMO
37
Examples of possible Failure Modes in Blanket/First Wall
(for solid and liquid breeder blanket concepts)
•
•
•
•
•
•
•
•
•
Cracking around a discontinuity/weld
Crack on shutdown (with cooling)
Solid breeder loses functional capability due to extensive cracking
Cracks in electrical insulators (for liquid metal blankets)
Cracks, thermal shock, vaporization, and melting during disruptions
First wall/breeder structure swelling and creep leading to excessive
deformation or first wall/coolant tube failure
Environmentally assisted cracking
Excessive tritium permeation to worker or public areas
Cracks in electrical connections between modules
Our concern is that failure rates may be much higher in fusion blankets because they appear
to be much more complex than steam generators and the core of fission reactors because
of the following points:
• Larger numbers of subcomponents and interactions (tubes, welds, breeder, multiplier,
coolant, structure, insulators, tritium recovery, etc.).
• More damaging, higher energy neutrons.
• Other environmental conditions: magnetic field, vacuum, tritium, etc. (for example, a leak
from the first wall or blanket module walls into the vacuum system results in failure, while in
steam generators and fission reactors, continued operation with leaks is often possible).
• Reactor components must penetrate each other; many penetrations have to be provided
through the blanket for plasma heating, fueling, exhaust, etc.
38
• Ability to have redundancy inside the blanket / first wall system is practically impossible.
Pillars of a Fusion Energy System
1. Confined and Controlled
Burning Plasma (feasibility)
2. Tritium Fuel Self-Sufficiency
(feasibility)
3. Efficient Heat Extraction and
Conversion (attractiveness)
4. Safe and Environmentally
Advantageous
(feasibility/attractiveness)
5. Reliable System Operation
(attractiveness)
The Blanket is the
KEY component
and is on the
critical path to
DEMO
Yet, No fusion blanket has ever been built or tested!
39
Reliability/Maintainability/Availability is one of the remaining
“Grand Challenges” to Fusion Energy Development.
FNT R&D is necessary to meet this Grand Challenge.
Need High Power Density/Physics-Technology Partnership
- High-Performance Plasma
- Chamber Technology Capabilities
Need Low
Failure Rate
C  i + replacement cost + O & M
COE =
P fusion  Availability  M  h th
Energy
Multiplication
Need High Temp.
Energy Extraction
Need High Availability / Simpler Technological and Material Constraints
(1 / failure rate )
1 / failure rate + replacemen t time
 Need Low Failure Rate:
- Innovative Chamber Technology
 Need Short Maintenance Time:
- Simple Configuration Confinement
- Easier to Maintain Chamber Technology
40
Major Activities and Approximate Timeline* for
Fusion Nuclear Technology Development
YEAR:
R&D
ITER
TBM
FNF
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Experiments in Non-Fusion Facilities: Thermal, MHD, Tritium, Fission, Accelerator Neutron Sources, etc.
Theory, Modeling and Computer Simulation
Machine Construction
Phase I: H-H/D-D/D-T
TBM Preparation
TBM (Fusion “break-in”)
Exploration & Decision
Engr. Design
Construction
?? Extended Phase ??
H-H
FNT Testing:
Engineering Feasibility
and Reliability Growth
System Analysis / Design Studies
 R&D Activities are critical to support effective FNT/Blanket
testing in ITER and FNF/CTF
 ITER TBM Provides Timely Information to FNF/CTF
* Need to adjust for new ITER Schedule delay of 2-3 years, similarly for FNF
Arrows indicate
major points of FNT
information flow
through ITER TBM
41
Approximate Costs of Blanket Testing
in the Fusion “Break-In” Stage
ITER
Facility Costs
Capital Cost
Operating Cost
(already paid for
regardless of TBM)
CTF
~ 2-4 billion dollars
~ $200 M/year
(for several years)
Cost of “Experiments”
(TBM plus ancilliary
equipment)
Minimum Cost is 24 TBM
($2M each) + 6 ancilliary
($8M each) = ~$96M
US pays $14M
US pays $96M
Other parties pay
the rest
Preparation Costs
(R&D, Mockups, Design…)
6 concepts x $80M/concept
= $480M
Accounting for common R&D
reduces cost to $240M
US pays $50M
Other parties pay
the rest
US pays $240M
42
TBM Testing in ITER Reduces Cost and Risk for FNT
Development and Shortens the Time to DEMO
•
ITER already has been designed with capabilities, worth billions of dollars, for testing TBMs,
both in hardware and the fusion DT environment capabilities it offers.
–
ITER operation costs are already paid for, and shared internationally, independent of TBM.
– The only cost for TBM is the cost of the TBM experiment (test article+PIE and
associated ancillary equipment), which is required for testing in any fusion
environment
•
•
Exactly the same R&D and qualification testing for ITER TBM will be needed for
CTF. But in ITER costs can be shared with international partners.
TBM in ITER provides fusion break-in tests and initial concept screening
–
–
•
Saves at least 2-3 years in CTF operation. This is a huge cost savings when given a CTF operating cost
of ~$200 million per year.
Saves on the cost of blanket concept screening by paying only partial cost for two concepts, while
getting access to results of many concepts of international parties
ITER TBM will shorten the operating time of CTF, and hence the time to DEMO.
–
–
–
Saving a few years on fusion “break-in” stage; allowing CTF to proceed directly to engineering
development and reliability growth
Results will allow better design, construction and operation of test modules for CTF. Thereby,
shortening the time required to complete FNT testing in CTF.
ITER is “real” and “unique.” It will provide the first prototypic fusion environment. It is likely to be the
only D-T fusion facility available during its first 10 year operation. Missing such a unique opportunity
increases the risk of delaying the DEMO schedule.
43
TBM Testing in ITER Reduces Cost and Risk for FNT
Development and Shortens the Time to DEMO (cont’d)
• ITER TBM, plus additional parallel R&D, is
important in providing a solution to the serious
tritium supply issue.
(Because of the large tritium consumption in ITER, any other fusion device,
e.g. CTF, with fusion power > 100 MW and availability of~ 25% will have to
breed its own tritium.)
– ITER TBM will enable CTF to construct near full
breeding blankets in an early stage
– ITER TBM will allow better designs of DEMO test
modules in CTF
•
ITER TBM will help CTF achieve its required availability sooner by
improving early-life reliability
•
Experience in safety and licensing of ITER TBM will be essential to the
licensing of CTF
44
TBM Testing in ITER (Phase I), combined with CTF, is
the most effective development path for FNT



FNT/Blanket development is critical to fusion
A strong base FNT R&D program, together with fusion environment testing is
essential
ITER is a unique, unparalleled and “real” opportunity to begin stage I fusion
break-in and scientific exploration
 ITER will provide the first opportunity (and likely the only one for many years) to
explore the fusion environment


Low fusion power CTF is required for stage II engineering feasibility, and stage
III reliability growth phases of FNT development
Even if CTF exists parallel to ITER, you still do TBM in addition to CTF
– If we do CTF and invest billions to test and develop FNT, this means we are serious.
The cost of experiments in ITER is very small and cuts years and huge costs from
the required CTF operation
– TBM tests in ITER will have prototypical Interactions between the FW/Blanket and
Plasma, thus complementing tests in CTF (if CTF plasma and environment are not
exactly prototypical, e.g. highly driven with different sensitivity to field ripple, low
outboard field with different gradients)
– Testing in any fusion environment will require same R&D, qualification, mockup
testing, testing systems, licensing as for ITER TBM, none of this effort for ITER
TBM is wasted
45
The US can benefit greatly from timely
international collaboration with ITER partners
 US ingenuity, innovation, and leadership on Fusion Nuclear
Technology have strongly influenced the world program over the
past 35 years
– Many parties have been continuously investing R&D resources in
concepts the US invented and which are still of US interest
 Other ITER parties are already committing significant resources to
their TBM programs
– But these parties won’t share their critical preparatory R&D, testing
facilities, and TBM experiment results, unless reciprocated
 All ITER parties have a strong interest to collaborate and work jointly
with the US (giving access information on a larger variety of blanket
concepts)
– But are concerned about the delay of an official US position and
commitment to Test Blanket experiments in ITER
An early signal of US commitment and intention of continued
leadership will enable negotiating international agreements that
best serve US strategic interests
46