Environmental Aspects of RecentTrend in Managing FusionRadwaste: Recycling and
Clearance, Avoiding Disposal
Environmental Aspects of RecentTrend in Managing FusionRadwaste: Recycling and
Clearance, Avoiding Disposal
L. El-GuebalyFusion Technology Institute
University of Wisconsin - Madisonhttp://fti.neep.wisc.edu/UWNeutronicsCenterOfExcellence
2nd IAEA TM onFirst Generation of Fusion Power Plants: Design & Technology
June 20 - 22, 2007Vienna, Austria
2
Handling Fusion Radioactive Materialsis Important to Future of Fusion Energy
• Background: Majority of fusion power plants designed to date focused on disposal ofactive materials in repositories, adopting fission waste management approach preferredin 1970’s.
• New Strategy: Develop new framework for fusion:– Minimal radwaste should be disposed of in ground– Recycle* and/or clear# all active materials, if technically and economically
feasible.
• Why?– Limited capacity of existing low-level waste repositories– Political difficulty of building new repositories– Tighter environmental controls– Minimize radwaste burden for future generations.
• Applications: Any fusion concept (MFE & IFE); power plants and experimental devices.
• Impact: Promote fusion as nuclear source of energy with minimal environmental impact._____________________* Reuse within nuclear industry.# Unconditional release to commercial market to fabricate as consumer products.
3
U.S. Repositories
• High-level waste (HLW) repositories:– Hanford facility in Washington:
• In operation since 1960.• 67,000 m3 capacity.
– Yucca Mountain repository in Nevada:• Planned to open in March 2017.• Total life cost $70B (originally estimated at $27B).• Capacity 70,000-120,000 tons (fission reactors generates 2,000 tons/y; 55,000 tons currently stored in 39 states).• Still needed even with fission spent fuel recycling program.• Not politically acceptable!
4
U.S. Repositories (Cont.)• Low-level waste (LLW) repositories:
– Barnwell facility in South Carolina:• 1971 – 2038.• Class A, B, C* LLW.• Supports east-coast reactors and hospitals.• Will severely curtail amount of LLW received in July 2008.• 36 states will lose access to Barnwell on 7/1/08, having no place to dispose 91% of
their Class B & C LLW.
– Richland facility in Washington:• Class C LLW.• 125,000 m3 capacity.• Supports 11 northwest states.
– Clive facility in Utah:• Class A LLW only.• Disposes 98% of U.S. Class A waste volume (does not accept sealed sources or biological tissue waste – a great concern for biotech industry).
_____________________* 0.1, 2, and 7 Ci/ft3 for Class A, B, and C waste, respectively.
5
U.S. Needs National Solution forLLW Problem
• LLW disposal is state responsibility, but no state would accept to be “nuclear dumpground” for the nation.
• Several states tried to developed disposal sites, then changed their mind because of strongopposition from public and environmentalists.
• Idaho state asked DOE to remove LLW stored at INL and ship it out of state.
• Utah state refused to open new Class C repository.
• Some utilities store LLW on site because of limited and expensive offsite disposal options.
• As near-term solution, DOE opened its disposal facilities to commercial LLW.
• Nuclear Regulatory Commission (NRC):– Favors permanent disposal instead of indefinite, onsite storage, but there is no
estimate of how long it would take to develop disposal facility.– Future availability of disposal capacity and disposal cost under current system
remain highly uncertain.
6
ARIES Designs(1988-2007)
ARIES-I ARIES-III ARIES-IV ARIES-RSSPPS
ARIES-ST
ARIES-AT
ARIES-CS
*
*LLNL
ARIES Team
UCSDUW
UCB
SNL
RPI
PPPL
NRLMITLBNL
LANL
INL
GT
GA
BoeingANL
7
Fusion Generates Large Amount of LLWthat Fills Repositories Rapidly
ITER
Economic Simplified Boiling Water Reactor(ESBWR) - Gen-III+
Reactor Vessel: 6.4 m ID, 21 m H
Fission
Fusion
20%LLW
80% Clearable
95% Clearable
5%LLW
1%HLW
8
Fusion Generates Large Amount of LLWthat Fills Repositories Rapidly (Cont.)
ARIES-ATAdvanced Tokamak
ARIES-ST Spherical Tokamak
Adv
ance
d Fi
ssio
n R
eact
orV
esse
l (ES
BWR
) (2
1 m
x 6
.4 m
)
Adv
ance
d Fi
ssio
n R
eact
orV
esse
l (ES
BWR
) (2
1 m
x 6
.4 m
)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Vo
lum
e (
10
3 m
3)
ARIES-ST
ARIES-AT
ESBWR
Class A & C LLW(active for 100s y)
HLW w/ TRU (active for 10,000 y)& Class C LLW
9
What We Suggest
• Business as usual is not environmentally attractive option.Something should be done.
• Fusion designs should adopt MRCB philosophy:
M – Minimize volume of active materials by design.
R – Recycle*, if economically and technologically feasible.
C – Clear# slightly-irradiated materials.B – Burn active byproducts, if any, in fusion devices@.
_____________________* Reuse within nuclear industry.# Unconditional release to commercial market to fabricate as consumer products.@ L. El-Guebaly, “Managing Fusion High Level Waste – a Strategy for Burning the Long-Lived Products in Fusion Devices,” Fusion Engineering and Design, 81 (2006) 1321-1326.
11
ARIES Project Committed toRadwaste Minimization
Tokamak waste volumehalved over 10 y study period
Stellarator waste volumedropped by 3-fold
over 25 y study period_____________________* Actual volumes of components (not compacted, no replacements).
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Bla
nke
t/S
hie
ld/V
acu
um
Ves
sel/M
agn
et/S
tru
ctu
re
Vo
lum
e (1
03 m3 )
ARIES – I1990
III1991
II1992
IV1992
RS1996
ST1999
AT2000
SiCSiC
SiC
V V
FS
FS(D-
3He)
Tokamaks*
0
1
2
3
4
5
6
7
8
Bla
nke
t/S
hie
ld/V
acu
um
Ves
sel/M
agn
et/S
tru
ctu
re
Vo
lum
e (1
03 m3 )
UWTOR-M24 m1982
SPPS14 m1994
ARIES-CS 8.25 m
2004
V FS
FS
ARIES-CS 7.75 m
2006
FS
FS
ASRA-6C20 m1987
Stellarators*
13
Disposal, Recycling, Clearance ApproachesApplied to Recent Fusion Studies
(red indicates preference)
Components Recycle? Clear? Dispose of @ EOL?
IFE:ARIES-IFE Targets# no yes / no yes
(for economic reasons) (as Class A)
Z-Pinch-IFE RTL* yes yes yes (carbon steel) (a must requirement) (as Class A)
MFE:ARIES-CS@ all yes yes / no yes
(as Class A & C)
______________________________# L. El-Guebaly, P. Wilson, D. Henderson, and A. Varuttamaseni, “Feasibility of Target Materials Recycling as Waste Management Alternative,”
Fusion Science & Technology, 46, No. 3, 506-518 (2004).* L. El-Guebaly, P. Wilson, and M. Sawan, “Activation and Waste Stream Analysis for RTL of Z-Pinch Power Plant,” To be published in Fusion
Science & Technology.@ L. El-Guebaly et al., “Designing ARIES-CS Compact Radial Build and Nuclear System: Neutronics, Shielding, and Activation,” To be published in
Fusion Science and Technology.
14
Economics Prevent Recycling ofARIES-IFE-HIB Hohlraum Wall
• Recycling of hohlraum walls doubles COE.• Hohlraum walls represent < 1% of waste
stream.• Once-through use generates Class A LLW.• Few materials (Au, Hg, Ta) have CI < 1.• Target factory designers prefer dealing
with non-radioactive hohlraum wallmaterials.
One-Shot Use RecyclingScenario Scenario
Cost per Target $ 0.4 $ 3.15Incremental Change to COE ~ 10 mills/kWh ~ 70 mills/kWhCost of Electricity (COE) ~ 70 mills/kWh ~ 130 mills/kWh
Hohlraum WallFoamsDT
Capsule(5 mm OD)
HIB
ARIES-IFE Target
2 cm
Preferred Option
15
Recycling is a “Must” Requirement for RTL of Z-Pinch toMinimize Radwaste Stream and Enhance Economics
Target
BreederJets
Breeder Foam
Recyclable Transmission LinesTop diameter = 1 m
Bottom diameter = 0.1 mLength = 2 m
Total thickness = 0.142 cm50 kg / RTL
100
101
102
103
104
105
106
107
108w/o RTL Recyclingw/ RTL Recycling
Was
te V
olu
me
(m3 )
ChamberWall
Building RTL Total
Chamber Wall
No recycling during 40 FPYTotal RTL volume = 7 M m3
With recycling1.1 day RTL inventoryTotal RTL volume = 0.0005 M m3
10-2
100
102
104
106
108
1010
103 104 105 106 107 108 109 1010 1011
Cle
aran
ce In
dex
Time After Shutdown (s)
Clearance Limit
100 y
IAEA
US
USw/o T
According to U.S. guidelines, RTL waste could be storedfor 50 y after plant decommissioning, then reused within
nuclear industry or released to commercial market
Z-Pinch Chamber
16
ARIES Compact Stellarator
2 m Bioshield
Cryostat
Blanket
Manifolds
Shield
VacuumVessel
Magnet
3 Field Periods.LiPb/He/FS System.7.75 m Major Radius.2.6 MW/m2 Average NWL.3 FPY Replaceable FW/Blanket.40 FPY Permanent Components.~78 mills/kWh COE ($2004).
ϕ = 0
ARIES-CS Cross Section @ ϕ = 0
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ARIES-CS LLW Classificationfor Geological Disposal
All ARIES-CSComponents(~8,000 m3)
Class ARepository
Class CRepository
~ 8 m belowground surface> 8 m below
ground surface+
Thick ConcreteSlab
TemporaryStorage
(up to 100 y)
≈
Class C Class A Could beLLW LLW Cleared?
FW/Blkt/BW √ no
Shield/Manifolds √ no
Vacuum Vessel √ no
Magnet:Nb3Sn √ noCu Stabilizer √ √JK2LB Steel* √ √Insulator √ √
Cryostat √ √
Bioshield √ √
(~6,600 m3)(82%)
(~1,400 m3)(18%)
Least hazardoustype of waste
______* Preferred over Incoloy-908 for clearance considerations.
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80% of ARIES-CS Active Materials can beCleared in < 100 y after Decommissioning
Recycle orDispose ofB/S/VV/M
(20%)
Clear Magnet w/o Nb
3Sn,
Cryostat & Bioshield(80%)
Cryostat
Blanket
Manifolds
ShieldVacuumVessel
Magnet
2 m Bioshield
Recycle orDispose of asClass A or C
Clear
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Not compacted, no replacementsFully compacted with replacements
Vo
lum
e (1
03 m3 )
FW/Blkt/BW
Shld/Mnfld
VV Magnets &Structure
Cryostat
10-2
100
102
104
106
108
1010
1012
100 102 104 106 108 1010 Pro
po
sed
U.S
. Cle
aran
ce In
dex
Time After Shutdown (s)
1d 1y
Inter-Coil Structure
Limit 100y
FW
Vacuum Vessel
Cryostat
Steel of Bldg
Concrete of Bldg
19
All ARIES-CS Components can be Recycled in < 1 yUsing Advanced RH Equipment
Cryostat
Blanket
Manifolds
ShieldVacuumVessel
Magnet
Bioshield
10-8
10-6
10-4
10-2
100
102
104
106
100 102 104 106 108 1010
Rec
yclin
g D
ose
Rat
e (S
v/h
)
Time After Shutdown (s)
Advanced RH Limit
Conservative RH Limit
Hands-onLimit1y1d
FW
Shield
Inter-Coil Structure
Steel of Bldg-IConc. of Bldg-I
VV
Cryostat
Development of more advanced RH equipment is foreseen to support fission GNEP initiative
20
Recycling & Clearance Flow Diagram
Original ComponentsReplaceableComponents
RecyclingFacility
TemporaryStorage
(~ 1 y)
Final Inspectionand Testing
Replaceable Components(@ 3 FPY)
Commercial Market(or Nuclear Industry)Commercial Market(or Nuclear Industry)
Blanket & DivertorFabrication and
Assembly
CI > 1
Fresh Supply(if needed)
MaterialsSegregation
NuclearIndustry
NuclearIndustry
Permanent Components @ EOL
CI < 1(SlightlyRadioactiveMaterials)
During OperationAfter Decommission
TemporaryStorage
Ore Mines& Mills
Ore Mines& Mills
21
General Observations
• Recycling and clearance options look promising and offer significantadvantage for radwaste minimization.
• They should be pursued despite lack of details at present.
• Fusion recycling technology will benefit from fission developments andaccomplishments in 50-100 y.
• Several critical issues still need further investigation for all three options:– Disposal– Recycling– Clearance
22
Disposal Issues
• Large volume to be disposed of (7,000 - 8,000 m3 per plant, includingbioshield).
• High disposal cost (for preparation, packaging, transportation, licensing,and disposal).
• Limited capacity of existing LLW repositories.
• Political difficulty of building new repositories.
• Tighter environmental controls.
• Radwaste burden for future generations.
23
Recycling Issues
• Development of radiation-hardened RH equipment (≥ 10,000 Sv/h).
• Energy demand and cost of recycling process.
• Radiochemical or isotopic separation processes, if needed.
• Any materials for disposal? Volume? Waste level?
• Properties of recycled materials? Reuse as filler? No structural role?
• Recycling plant capacity and support ratio.
• Acceptability of nuclear industry to recycled materials.
• Recycling infrastructure.
24
Clearance Issues
• Discrepancies between clearance standards*.
• Lack of consideration for numerous fusion radioisotopes*: (10Be, 26Al, 32Si, 91,92Nb, 98Tc, 113mCd, 121mSn, 150Eu, 157,158Tb,
163,166mHo, 178nHf, 186m,187Re, 193Pt, 208,210m,212Bi, and 209Po).
• Impact of missing radioisotopes on CI prediction.
• Need for fusion-specific clearance limits*.
• Clearance infrastructure.
• Availability of clearance market (none anywhere in the world, except inGermany and Spain. Currently, U.S. industries do not support unconditionalclearance claiming it could erode public confidence in their products and damagetheir markets).
______________________________* L. El-Guebaly, P. Wilson, and D. Paige, “Evolution of Clearance Standards and Implications for Radwaste Management of Fusion Power Plants,” Fusion Science & Technology, 49, 62-73 (2006).
10-5
10-3
10-1
101
103
0 50 100 150 200 250 300
Rat
io o
f P
rop
ose
d U
S t
o IA
EA
Cle
aran
ce L
imit
s fo
r C
on
cret
e
Atomic Mass of Radioisotopes
10-5
10-3
10-1
101
103
0 50 100 150 200 250 300Rat
io o
f P
rop
ose
d U
S t
o IA
EA
C
lear
ance
Lim
its
for
Ste
el
Atomic Mass of Radioisotopes
25
Q / A
General public and government agencies ask for energy source that:– is safe– generates little or no waste– does not deplete limited natural resources.
Question: Which option helps earn public acceptance? Disposal or recycling/clearance?
Disposal Recycling/Clearance
Generates little or no waste √
Does not deplete limited natural resources √
26
Recommendations
Fusion designers:– Continue developing low-activation materials.– Promote environmentally attractive scenarios such as recycling and clearance,
avoid geological burial, and minimize radwaste volume by design.– Identified critical issues should be investigated for all three options.– Technical and economic aspects must be addressed before selecting most
suitable radwaste management approach for any fusion component.
Nuclear industry and organizations:– Nuclear industry must accept recycled materials from dismantled nuclear
facilities.– National and international organizations (NRC, IAEA, etc.) should continue
their efforts to convince industrial and environmental groups that clearance canbe conducted safely with no risk to public health.