Overview of the INL
Fusion Safety
Program
PbLi-T Workshop
11-12 June 2007
Idaho Falls, ID
Fusion Safety Program
Outline
•
•
STAR
Dust
•
•
•
•
•
Tritium Material Interactions and Permeation
Fusion Safety Codes
Risk
Waste Management
Safety Design Analysis
•
Summary
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 1
Fusion Safety Program
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 2
Fusion Safety Program
STAR Floorplan Layout
Glovebox TCS
Tritium SAS
Stack monitor
Chemical reactivity
D-ion implantation
TPE
2LiF-BeF2 preparation,
purification and testing
MS tritium exp
MS corrosion exp
15,000 Ci tritium limit
Segregation of operations
Gloveboxes and hoods
Tritium cleanup system
Once-through room ventilation
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 3
Fusion Safety Program
Star Tritium Storage and Assay System
Secondary inlet
Primary outlet
U-bed-1
U-bed-2
SAS glovebox Setup
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
SAS manifold with U-beds
SAS manifold and
vacuum pumps
Slide 4
Fusion Safety Program
STAR Tritium Cleanup System (TCS)
Outlet IC
Inlet
Inlet sample loop
Condenser
Control
Heat exchanger
MS water
Mole sieve bed
Blower
Catalyst beds
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 5
Fusion Safety Program
Tritium at STAR
•
Useable tritium inventory now 1300 Ci
–
300 Ci in equimolar H2:D2:T2 calibration standard
–
–
1000 Ci T2 available for experiments
shipments from SRS limited to 1000 Ci with standard TYPE-A
shipping container
next shipment (1000 Ci) expected in Fall 2007
–
Shipping Vessel (1 available)
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 6
Fusion Safety Program
May 1995 - First tritium plasma
experiments at TSTA
September 2000 - Final tritium
plasma experiments at TSTA
History of TPE
March 2002 - Extraction,
loading, and transport
April 8, 2002 - Depart LANL
February 2001 - Begin D&D
efforts of TPE
December 2001 - Final pump
out of system; close all valves
January 2002 - Preparation
for shipment
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
April 10, 2002 - Arrival at INL
STAR Facility
Summer/
Fall 2002 Uncrate and
decon ancilliary
components
January 2003 Modify plans
for location of
experiment,
decide on PermaCon structure, initiate facility
design changes. June 2003- PermaCon installed,
TPE glovebox uncrated. 2004- Reassembly and
system interface design activities
Spring &
Summer 2005
Electrical
Service
re-design
& construction,
experiment
& facility
interface
assemblies
completed
Fall 2005 - Integrated systems testing initiated
December
2005 - First
plasma testing
(non-tritium)
Slide 7
Fusion Safety Program
Planned Research Agenda for TPE
• Study uptake, retention and permeation in PFCs
– Measurement of bulk tritium transport properties (diffusivity,
solubility, dissociation/recombinatino rates)
– Monomaterials (Be, W, C)
– Mixed materials
– Bonded and/or duplex structures
– Effects of neutron dose and irradiation temperature on tritium
trapping
• Certification of these structures for ITER
• Use of tritium in the plasma will enable low level
measurements needed for such research
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 8
Fusion Safety Program
Flibe Tritium Experiment
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
•
Tritium provided in
pressurized vessel
containing D2/T2
mixture
•
Glovebox setup to
contain potential
leaks
•
Localized tritium
cleanup will be
connected
•
GC column accurately
measures H
concentration; tritium
release measured
with ion chamber
•
well-characterized
with D2; now
experiment with T2
Slide 9
Fusion Safety Program
Permeation Coating Barrier Experments
Thermal Cycle Performance of He Pipe Permeation Barriers
• simulates thermal stress
degradation of permeation barrier
coatings for He pipes
• configuration matched to TBM
design for coated components
• utilize tritium for barrier
technology qualification
• external thermal cycles followed
by testing in permeation rig for
integrated effects
• in-situ thermal cycling in
permeation rig for barrier dynamic
response
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 10
Fusion Safety Program
Dust generation
ITER Key Issues: chemical reactivity, radioactivity
content, dust explosions.
Science: understand and model underlying formation mechanisms to
estimate inventories expected in fusion
ITER Dust Strategy from EDA
Demonstration
of the filtered
vacuum
collection
technique
Key scientific issues
needing resolution
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 11
Fusion Safety Program
Dust Characterization
Particle Size Distribution, Specific Surface Area, Surface Mass Density,
Composition, Shape and Tritium Content
Specific Surface Area
100
Comparison of Size Distributions
Machine
Lower
Regions
Middle
Regions
Upper
Regions
0.89 + 2.92
DIII-D
0.66 + 2.82
0.60 + 2.35
TFTR
0.88 + 2.63
1.60 + 2.33
Alcator-Cmod
1.58 + 2.80
1.53 + 2.80
JET
27 + (-)
-
-
TEXTOR
5-20 + (-)
-
-
Tore Supra
2.68 + 2.89
2.98 + 2.94
1.22 + 2.03
3.32 + 2.94
2.21 + 2.93
3.69 + 2.81
3.59 + 3.08
LHD
8.59 + 2.67
6.31 + 2.39
8.73 + 2.09
NOVA
1.12 + 1.90
0.76 + 2.03
0.90 + 1.93
10
1
fully dense C
fully dense Mo
TFTR
DIII-D
Alcator-Cmod
Tore Supra
ASDEX-Upgrade
NOVA
JET
ATJ graphite
0.1
0.01
1
R&D continues to resolve the issues
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
C
Mo
10
Mean Volume-Surface Diameter, d
100
MVS
(µm)
Dust Size versus Surface Mass Density
15
Median Particle Diameter (µm)
ASDEX-Upgrade
2 /g
CMD (µm) + GSD
Specific Surface Area, m
SSA_data
LHD
ASDEX-Upgrade
Tore Supra
CMOD_(98)
DIIID_(98)
10
LHD
5 ASDEX-Upgrade
Tore Supra
CMOD
DIII-D
0
100
101
102
Surface Mass Density (mg/m
2
103
)
104
Slide 12
Fusion Safety Program
Research Agenda for Dust
• Continued characterization in existing tokamaks
•
•
•
•
Mobilization testing
Chemical reactivity of dust in grooves
Dust explosion testing
Monitoring and removal evaluation
• Improved strategy for ITER
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 13
Fusion Safety Program
Major Accomplishments in
Risk Assessment for Fusion
•
•
Work on component failure rate data to support quantitative safety
assessment continues to be very successful.
– Initially, component failure rates were collected from handbooks
and applied to fusion.
– Now, through IEA Task 5, we collect fusion facility operating
experience data from TLK, TPL, and the former TSTA; and tokamak
data from DIII-D and JET.
– Independent data sets validate the failure rate values.
Occupational safety is a new area for risk assessment.
– ITER IT has plans to perform a room-by-room overall assessment
of the ITER facility to identify occupational hazards
– Occupational injury rates have been collected from several US
tokamaks and large particle accelerators
– WE-FMEA method was developed to address highly hazardous
equipment failures in a fusion facility, such as high energy pipe
breaks that have caused worker fatalities in the power industry
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 14
Fusion Safety Program
The Hazard Zone of the Worker Exposure Failure Modes and Effects (WE-FMEA)
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 15
Fusion Safety Program
INL FSP Support of the ITER Project
• The FSP is supporting the ITER Project through three Implementing
Task Agreements (ITA):
•
Fusion Safety Code Support
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–
–
•
Magnet Safety
–
–
–
•
Provide International Team (IT) with the latest fusion versions of the MELCOR and ATHENA
codes, documentation, validation, and support and assistance at operation of the codes.
Delivered MELCOR 1.8.5, upgraded ice layer model for cryogenic surfaces, and developed a
beryllium dust layer oxidation model for MELCOR
Assist the ITER IT in producing the QA documentation for MELCOR and safety analyses for
ITER’s Report on Preliminary Safety (RPrS)
Update the MAGARC code to current ITER design for TF and PF coils, include new R&D
results on insulation failure behavior at elevated temperatures, apply the MAGARC code to
various ITER magnet safety studies
Upgraded insulation and magnet parameters, implemented arc limit model, applied MAGARC
to ITER-FEAT TF and PF magnet unmitigated quench events
Develop magnet Busbar arc capability for MAGARC
Dust Issues
–
–
Characterize and quantify amounts generated during ITER operation
Reactivity/explosivity, mobilization, and transport during accident conditions
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 16
Fusion Safety Program
MELCOR Code Heat Structure Dust Layer
Oxidation Model
•
•
A beryllium dust layer oxidation
model was developed for ITER to
simulate oxidation of a dust layer of
dust that has settled onto a heated
surface inside of a fusion device
This model is based on measured
oxidation reaction rates for fully
dense beryllium, binary gaseous
diffusion of oxygen or steam into the
dust layer, and BET measured
specific surface area for beryllium
dust
Application is for slow vacuum vessel
pressurization events from in-vessel
loss-of-cooling accidents (LOCAs)
and loss-of-vacuum accidents
(LOVAs)
10
0
INL92
88% dense
Beryllium oxidation rate (kg/m2-s)
•
10
MELCOR dust layer model
(Dust=0.7g/cm3, dp= 20mm)
-3
INL98 88% dense
INL Dust
10
-6
10
-9
10
-12
INL fully dense
5
10
15
20
10,000/T (K)
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 17
Fusion Safety Program
MAGARC Poloidal Field Coil Development
•
The MAGARC code was recently
modified to analyze unmitigated
quench events in ITER poloidal
field (PF) magnets
•
This modification include
the electrical
characteristics of the twoin-hand winding pair of the
ITER PF coils and limits
on the number of arcs that
can form in the magnet
during unmitigated quench
events based on an
energy minimization
principle.
Winding pair
Voltage (V)
Axial direction
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Radial direction
Inline arcs
voltage drops
Time 110s
Slide 18
Fusion Safety Program
MAGARC Poloidal Field Coil Application
MAGARC code
application to
unmitigated
quench events in
ITER poloidal field
(PF) magnets
4.0
Coil current (kA)
Lead voltage drop (V)
•
3000
2000
1500
1000
0
0
300
Time (s)
450
0.0
600
4
2
0.6
0.4
0.2
0
150
300
Time (s)
450
600
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
0
150
300
Time (s)
450
600
0.12
Melt volume (m3)
Quench fraction
Number of arcs
6
0
150
0.8
Inline
Radial
Axial
2.0
1.0
500
8
3.0
0.08
0.04
0.00
0.0
0
150
300
Time (s)
450
600
0
150
300
450
Time (s)
600
Slide 19
Fusion Safety Program
Future Safety Code Activities
• MAGARC capabilities will be expanded to treat arcs in
magnet busbars by including the magnetic effects of the
arc that forms between the leads of a busbar. As part of
an international collaboration, this new capability will be
validated against data that has recently been obtained
from the MOVARC experiment at FzK in Germany
• Work with the ITER IT to provide the necessary quality
assurance documentation required for ITER licensing for
the MELCOR code
• Continue in support of the licensing process for the US
DCLL TBM to complete Dossier on Safety for this TBM
concept
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 20
Fusion Safety Program
MELCOR Code
Applied to ARIES-CS
ARIES-CS has Dual Cooled Liquid
Lead Lithium (DCLL) Blanket
•
This blanket concept employees
reduced activation ferritic steel
(RAFS) for the structure, cooled by
8 MPa helium, and a self-cooled
breeding zone cooled by flowing
PbLi.
•
Helium pressurization accidents will
be a concern for this concept, with
the reactor cryostat serving as
secondary radioactivity and
pressure confinement
•
Because stellarator plasmas do not
disrupt, the beyond design basis
bypass accident (BDBA) of concern
may be a heat exchanger tube
breach in the PbLi/Brayton cycle
system, leaking 10 MPa helium into
the blanket causing a blanket break
and pressurization of the vacuum
vessel
0.25
Vacuum Vessel
Cryostat
Pressure (MPa)
•
0.20
0.15
0.10
0.05
0.00
3600
3700
3800
Time (s)
3900
4000
Initial results for in-vessel FW helium LOCA
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 21
Fusion Safety Program
MELCOR Code Applied to US Test Blanket
Module Safety Assessment
•
•
•
Evaluate consequences to ITER
from accidents in the proposed
US DCLL Test Blanket module
(TBM)
To date three accident
scenarios have been
investigated:
– In-vessel TBM coolant leaks
– In-TBM breeding zone
coolant leaks
– Ex-vessel TBM cooling
system leaks
No significant impacts on ITER
safety have been identified, but
assessment is still ongoing
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Internal
PbLi flow
• All FS structures
are He-cooled by
8 MPa
• PbLi self-cooled
flows in poloidal
direction
He out
He in
PbLi
concentric
inlet/outlet
pipe
Slide 22
Fusion Safety Program
Recent Trends in Radwaste
Management
•
Options:
– Disposal in repositories: LLW (WDR < 1) or HLW (WDR > 1)
– Recycling – reuse within nuclear facilities (dose < 3000 Sv/h)
– Clearance – release slightly-radioactive materials to commercial
market if CL < 1.
•
Tighter environmental controls and the political difficulty of
building new repositories worldwide may force fusion designers
to promote recycling and clearance, avoiding geological disposal
 No radwaste burden on future generation.
•
There’s growing international effort in support of this new trend.
•
Recycling may not be economically feasible for all fusion
components.
•
Recycling of liquids and solids may generate limited amount of
radioactive waste that needs special treatment.
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 23
Fusion Safety Program
S&E considerations are critical
for the success of IFE
•
IFE has both radiological and toxicological hazards:
– Tritium fuel, activated structural material, activated dust, activated
coolants or coolant impurities, and activated gases
– Chemically toxic materials (i.e.: Hg, Pb)
•
Energy sources that can mobilize these hazardous materials include:
– chemical energy, decay heat, pressure energy, electrical energy and
radiation
•
In the US, current IFE S&E activities, are focused on a few programs:
– The High Average Laser Program (HAPL)
– The Z-IFE Program
– The National Ignition Facility (NIF): not exactly an IFE program but
closely linked to the future of IFE research
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 24
Fusion Safety Program
Summary
• US S&E research continues to help improve fusion facility design in
terms of accident safety, worker safety, and waste disposal.
• The R&D underway and currently planned in the areas of dust and
tritium source terms will answer important questions for ITER and
future machines.
• Regulatory approval of ITER and the associated verification and
validation activities for our fusion safety codes and risk and
reliability methods will provide greater confidence in application of
these tools to evaluate public and worker safety of future fusion
facility designs.
• The resurgence of nuclear fission reactor construction activities
worldwide will cause increased attention to waste management
issues associated with nuclear power which in turn should help
fusion as it develops a long term waste management strategy
consistent with on-going US regulation.
• Safe and environmentally sound operation of both ITER and NIF
will be important public demonstrations of the S&E potential of
fusion.
PbLi-T 2007, Idaho Falls, ID, 11-12 June 2007
Slide 25