ARIES-CS Radial Build Definition and Nuclear System Characteristics L. El-Guebaly, P. Wilson, D....
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Transcript of ARIES-CS Radial Build Definition and Nuclear System Characteristics L. El-Guebaly, P. Wilson, D....
ARIES-CS Radial Build Definition and
Nuclear System Characteristics
ARIES-CS Radial Build Definition and
Nuclear System Characteristics
L. El-Guebaly, P. Wilson, D. Henderson, T. Tautges,
M. Wang, C. Martin, J. Blanchardand the ARIES Team
Fusion Technology InstituteUW - Madison
US / Japan Workshop on Power Plant StudiesJanuary 24 - 25, 2006
UCSD
2
Nuclear Areas of Research
VV
Blanket
Shield
Magnet
Manifolds
Radial Build Definition:– Dimension of all components
– Optimal composition
High-performance shielding module at min
Neutron Wall Loading Profile:– Toroidal & poloidal distribution
– Peak & average values
Blanket Parameters:– Dimension– TBR, enrichment, Mn
– Nuclear heat load– Damage to FW– Service lifetime
Radiation Protection:– Shield dimension & optimal
composition– Damage profile at shield,
manifolds, VV, and magnets– Streaming issues
Activation Issues:– Activity and decay heat– Thermal response to
LOCA/LOFA events – Radwaste management
3
Nuclear Task Involves Active Interaction with many Disciplines
1-D Nuclear Analysis(∆min, TBR, Mn, damage, lifetime)
Activation Assessment(Activity, decay heat, LOCA/LOFA,
Radwaste classification)
3-D Neutronics(Overall TBR, Mn)
Radial Build Definition@ ∆min and elsewhere
(Optimal dimension and composition,blanket coverage, thermal loads )
NWL Profile( peak, average, ratio)
Prelim. Physics(R, a, Pf, ∆min, plasma contour, magnet CL)
DesignRequirements
no ∆min match
or insufficient breeding
Init. DivertorParameters
Init. MagnetParameters
Blanket Concept
Systems Code(R, a, Pf)
CAD Drawings
Safety Analysis
Blanket Design
4
Stellarators Offer Unique Engineering Features and Challenges
• Minimum radial standoff at min controls machine size and cost. Well optimized radial build particularly at min
• Sizable components with low shielding performance (such as blanket and He manifolds) should be avoided at min.
• Could design tolerate shield-only module (no blanket) at min? Impact on TBR, overall size, and economics?
• Compactness mandates all components should provide shielding function:– Blanket protects shield– Blanket and shield protect manifolds and VV– Blanket, shield, and VV protect magnets
• Highly complex geometry mandates developing new approach to directly couple CAD drawings with 3-D neutronics codes.
• Economics and safety constraints control design of all components from beginning.
5
ARIES-CS Requirements Guide In-vessel Components Design
Overall TBR 1.1 (for T self-sufficiency)
Damage to Structure 200 dpa - advanced FS (for structural integrity) 3% burn up - SiC
Helium Production @ Manifolds and VV 1 appm (for reweldability of FS)
S/C Magnet (@ 4 K): Fast n fluence to Nb3Sn (En > 0.1 MeV) 1019 n/cm2
Nuclear heating 2 mW/cm3 dpa to Cu stabilizer 6x10-3 dpa
Dose to electric insulator > 1011 rads
Machine Lifetime 40 FPY
Availability 85%
6
Reference Dual-cooled LiPb/FS Blanket Selected with Advanced LiPb/SiC as Backup
Breeder Multiplier Structure FW/Blanket Shield VVCoolant Coolant Coolant
Internal VV:
Flibe Be FS Flibe Flibe H2O
LiPb (backup) – SiC LiPb LiPb H2O
LiPb (reference) – FS He/LiPb He H2O
Li4SiO4 Be FS He He H2O
External VV:
LiPb – FS He/LiPb He or H2O He
Li – FS He/Li He He
7
FW Shape Varies Toroidally and Poloidally - a Challenging 3-D Modeling Problem
min
Beginning of FieldPeriod
Middle of FieldPeriod
= 0
= 60
3 FPR = 8.25 m
8
UW Developed CAD/MCNP Coupling Approach to Model ARIES-CS for Nuclear Assessment
• Only viable approach for ARIES-CS 3-D neutronics modeling.
• Geometry and ray tracing in CAD; radiation transport physics in MCNPX.
• This unique, superior approach gained international support.
• Ongoing effort to benchmark it against other approaches developed abroad
(in Germany, China, and Japan).
• DOE funded UW to apply it to ITER - relatively simple problem.
CAD geometry engine Monte Carlo
methodRay object intersection
CAD based Monte Carlo Method
CAD geometry file Neutronics
input file
9
3-D Neutron Wall Loading ProfileUsing CAD/MCNP Coupling Approach
IB OB
– R = 8.25 m design.– Neutrons tallied in discrete bins:
– Toroidal angle divided every 7.5o.– Vertical height divided into 0.5 m segments.
– Peak ~3 MW/m2 at OB midplane of = 0o – Peak to average = 1.52
= 0
= 60
Peak
10
Novel Shielding Approach Helps Achieve Compactness
Benefits:– Compact radial build at min – Small R and low Bmax
– Low COE.
Challenges:– Integration of shield-only and transition
zones with surrounding blanket.– Routing of coolants to shield-only zones.– Higher WC decay heat compared to FS.
WC Shield-only Zone(6.5% of FW area)
Transition Zone(13.5% of FW area)
11
Toroidal / Radial Cross Section(R = 8.25 m )
| | WC-Shield only Zone (~6.5%)
Transition Region (~13.5%)
Nominal Blanket/shieldZone (~80%)
Plasma
Magnet
Vacuum Vessel
WC-Shield-II
WC-Shield-I
Blanket
FS-Shield
FWSOL
Back Wall
Gap
Non-uniformBlanket
LiPb & He Manifolds
4
17
5
28
35
28
5438
8
13
38
28
min =
119
cm
5 cm
Divertor System(10% of FW area)
12
Radial Build Satisfies Design Requirements (3 MW/m2 peak )
||Thickness
(cm)
ShieldOnlyZone
@ min VV
Blanket
Shield
Magnet
WC
Shi
eld-
only
or
Tra
nsit
ion
Reg
ion
Manifolds
Thickness(cm)
Blanket/ShieldZone
> 181 cm
SO
L
Vac
uu
m V
esse
l
FS
Sh
ield
3.8
cm F
W
Gap
+ T
h. I
nsu
lato
r
Win
din
g P
ack
Pla
sma
5 >2 ≥228 312.228
Coi
l Cas
e &
In
sula
tor
5 cm
BW
Ext
ern
al S
tru
ctu
re
10
25 cmBreeding
Zone-I
25 cmBreeding Zone-II
0.5 cmSiC Insert
1.5 cm FS/He
1.5
cm F
S /H
e
63| | 35
Man
ifol
ds
SO
L
Vac
uu
m V
esse
l
Bac
k W
all
Gap
Gap
+ T
h. I
nsu
lato
r
Coi
l Cas
e &
In
sula
tor
Win
din
g P
ack
Pla
sma
5 17
|
5
FW
Ext
ern
al S
tru
ctu
re
1.5 cm FS/He
WC
Sh
ield
-I(r
epla
cea b
l e)
38
WC
Sh
ield
-II
(per
man
ent)
min = 119 cm
28 2
Gap
2
Replaceable | Permanent Components
13
Blanket Design Meets Breeding Requirement
• Local TBR approaches 1.3• 3-D analysis confirmed 1-D local TBR estimate for full blanket coverage.• Uniform and non-uniform blankets sized to provide 1.1 overall TBR based
on 1-D results combined with blanket coverage. To be confirmed with detailed 3-D model.
0.0
0.5
1.0
1.5
0 20 40 60 80
Thickness of Breeding Zone (cm)
3.8cm He-Cooled FWHe-Cooled FS-Shield
FullBlanket
14
Preliminary 3-D Results Using CAD/MCNP Coupling Approach
Model* 1-D 3-D
Local TBR 1.285 1.316 ± 0.61%
Energy multiplication (Mn) 1.14 1.143 ± 0.49%
Peak dpa rate (dpa/FPY) 40 39.4 ± 4.58%
FW/B lifetime (FPY) 5 5.08 ± 4.58%
Nuclear heating (MW):FW 156 145.03 ±1.33%Blanket 1572 1585.03 ±1.52%Back wall 13 9.75 ± 6.45%Shield 71 62.94 ± 2.73%Manifolds 18 19.16 ± 5.49%Total 1830 1821.9 ± 0.49%
____________________________* Homogenized components. Uniform blanket everywhere. No divertor. No penetrations. No gaps.
Future 3-D analysis will include blanket variation, divertor system and penetrations to confirm 1.1 overall TBR and Mn.
15
He Access Tubes Raise Streaming Concern
||Thickness
(cm)
ShieldOnlyZone
@ min VV
Blanket
Shield
Magnet
WC
Shi
eld-
only
or
Tra
nsit
ion
Reg
ion
Manifolds
Thickness(cm)
Blanket/ShieldZone
> 181 cm
SO
L
Vac
uu
m V
esse
l
FS
Sh
ield
3.8
cm F
W
Gap
+ T
h. I
nsu
lato
r
Win
din
g P
ack
Pla
sma
5 ? ≥228 302.228
Coi
l Cas
e &
In
sula
tor
5 cm
BW
Ext
ern
al S
tru
ctu
re
10
25 cmBreeding
Zone-I
25 cmBreeding Zone-II
0.5 cmSiC Insert
1.5 cm FS/He
1.5
cm F
S /H
e
63| | 35
Man
ifol
ds
Loc
al S
hie
ld
He Tube(32 cm ID)
SO
L
Vac
uu
m V
esse
l
Bac
k W
all
Gap
Gap
+ T
h. I
nsu
lato
r
Coi
l Cas
e &
In
sula
tor
Win
din
g P
ack
Pla
sma
5 17
|
5
FW
Ext
ern
al S
tru
ctu
re
1.5 cm FS/He
WC
Sh
ield
-I(r
epla
cea b
l e)
38
WC
Sh
ield
-II
(per
man
ent)
min = 119 cm
28 2
16
Local Shield Helps Solve Neutron Streaming Problem
Pla
s ma
Ba c
k W
all
FW
/Bla
nk
et Shie
ld
Man
ifol
ds
VV
Mag
ne t
He Access Tube
Loc
al S
hiel
d
0
10
20
30
40
No TubeI-D
Limit
2-D with 20 cm Local Shield
2-D
No Local Shield
with TubeOngoing 3-D analysis will optimize dimension of local shield
Hot spots at VV and magnet
17
Key Design Parameters for Economic Analysis
Integral system analysis will assess impact ofmin, Mn, and th on COE
LiPb/FS/He LiPb/SiC(reference) (backup)
min 1.19 1.14
Overall TBR 1.1 1.1
Energy Multiplication (Mn) 1.14 1.1
Thermal Efficiency (th) 40-45%* 55-63%*
FW Lifetime (FPY) 5 6
System Availability ~85% ~85%
__________* Depending on peak .
18
Activation Assessment
• Main concerns:
– Decay heat of FS and WC components.
– Thermal response of blanket/shield during LOCA/LOFA.
– Waste classification:- Low or high level waste?
-Any cleared metal?
– Radwaste stream.
19
Decay Heat
WC decay heat dominates at 3 h after shutdown
102
103
104
105
106
100 101 102 103 104 105 106 107
Time After Shutdown (s)
1h 1d 1w
FS of Blanket-I
FWWC Shield-I
LiPb
20
Thermal Response duringLOCA/LOFA Event
• 3-coolant system rare LOCA/LOFA event (< 10-8/y) • Severe accident scenario: He and LiPb LOCA in all blanket/shield modules
& water LOFA in VV.• For blanket, FW temperature remains below 740 oC limit.• WC shield modules may need to be replaced. More realistic accident scenario
will be assessed.
Nominal Blanket/ShieldTmax ~ 711 oC
Shield-only Zone
Tmax ~ 1060 oC
740 C temp limit
1 s 1 m 1 h 1 d 1 mo
740 C temp limit
1 s 1 m 1 h 1 d 1 mo
21
Waste Management Approach
• Options:– Disposal in LLW or HLW repositories– Recycling – reuse within nuclear facilities– Clearing – release to commercial market, if CI < 1.
• Repository capacity is limited:– Recycling should be top-level requirement for fusion
power plants– Transmute long-lived radioisotopes in special module– Clear majority of activated materials to minimize waste
volume.
22
ARIES-CS Generates Only Low-Level Waste
WDRReplaceable Components:
FW/Blanket-I 0.4WC-Shield-I 0.9
Permanent Components:WC-Shield-II 0.3FS Shield 0.7Vacuum Vessel 0.05Magnet < 1Confinement building << 0.1
LLW (WDR < 1) qualifies for near-surface disposal or, preferably, recycling
23
Majority of Waste (74%) can be Cleared from Regulatory Control
0
2000
4000
6000
8000
Blanket BuildingShield/VV Magnet
14%
5% 7%
74%
Dispose or Recycle
Clear10-1
101
103
105
107
109
1011
100 102 104 106 108 1010
Time After Shutdown (s)
1h 1d1y
Shield
Limit 100y
Blanket
Vacuum Vessel
Magnet
Building
In-vessel components cannot be cleared
24
Building Constituents can be Cleared 1-4 y after Plant Decommissioning
Building composition: 15% Mild Steel, 85% Concrete
10-4
10-2
100
102
104
100 102 104 106 108 1010
Time After Shutdown (s)
1h 1d
IAEA
Limit
100y
US
InnermostSegmentMild Steel
3.5 y
10-4
10-3
10-2
10-1
100
101
102
103
104
100 102 104 106 108 1010
Time After Shutdown (s)
1h 1d1.3 y
IAEA
Limit
100y
US
InnermostSegmentConcrete
25
Stellarators Generate Large Radwaste Compared to Tokamaks
Means to reduce ARIES-CS radwaste are being pursued(more compact machine with less coil support and bucking structures)
FW
BackWall
Blanket
Shield
CoilStructure Manifolds
V V
WP
BuckingCylinder
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
ARIES - I III II IV RS ST ATSPPS CS
SiCSiC
SiC
V V
V
FS
FS(D-
3He)
FS
Stellarators not compacted, no replacements
26
Well Optimized Radial Build Contributed to Compactness of ARIES-CS
Over past 25 y, stellarator major radius more than halved by advanced physics and technology, dropping from 24 m for UWTOR-M to 7-8 m for ARIES-CS,
approaching R of advanced tokamaks.
UWTOR-M24 m
0 5 10 15 20 25
2
4
6
8
m
Average Major Radius (m)
ASRA-6C20 m
HSR-G18 m
SPPS14 mFFHR-J
10 m
ARIES-CS
ARIES-STSpherical Torus
3.2 m
ARIES-ATTokamak
5.2 m
Stellarators||
7 m 8.25 m
198219872000199620002005
27
Concluding Remarks
• Novel shielding approach developed for ARIES-CS. Ongoing study is assessing benefits and addressing challenges.
• CAD/MCNP coupling approach developed specifically for ARIES-CS 3-D neutronics modeling.
• Combination of shield-only zones and non-uniform blanket presents best option for ARIES-CS.
• Proposed radial build satisfies design requirements.
• No major activation problems identified for ARIES-CS.
• At present, ongoing ARIES-CS study is examining more compact design (R < 8 m) that needs further assessment.
28
ARIES-CS Publications
L. El-Guebaly, R. Raffray, S. Malang, J. Lyon, and L.P. Ku, “Benefits of Radial Build Minimization and Requirements Imposed on ARIES-CS Stellarator Design,” Fusion Science & Technology, 47, No. 3, 432 (2005).
L. El-Guebaly, P. Wilson, and D. Paige, “Initial Activation Assessment of ARIES Compact Stellarator Power Plant,” Fusion Science & Technology, 47, No. 3, 440 (2005).
M. Wang, D. Henderson, T. Tautges, L. El-Guebaly, and X. Wang, “Three -Dimensional Modeling of Complex Fusion Devices Using CAD-MCNP Interface,” Fusion Science & Technology, 47, No. 4, 1079 (2005).
L. El-Guebaly, P. Wilson, and D. Paige, “Status of US, EU, and IAEA Clearance Standards and Estimates of Fusion Radwaste Classifications,” University of Wisconsin Fusion Technology Institute Report, UWFDM-1231 (December 2004).
L. El-Guebaly, P. Wilson, and D. Paige, “Evolution of Clearance Standards and Implications for Radwaste Management of Fusion Power Plants,” Journal of Fusion Science & Technology, 49, 62-73 (2006).
M. Zucchetti, L. El-Guebaly, R. Forrest, T. Marshall, N. Taylor, K. Tobita, “The Feasibility of Recycling and Clearance of Active Materials from Fusion Power Plants,” Submitted to ICFRM-12 conference at Santa Barbara (Dec 4-9, 2005).
L. El-Guebaly, R. Forrest, T. Marshall, N. Taylor, K. Tobita, M. Zucchetti, “Current Challenges Facing Recycling and Clearance of Fusion Radioactive Materials,” University of Wisconsin Fusion Technology Institute Report, UWFDM-1285. Available at: http://fti.neep.wisc.edu/pdf/fdm1285.pdf
L. El-Guebaly, “Managing Fusion High Level Waste – a Strategy for Burning the Long-Lived Products in Fusion Devices,” Fusion Engineering and Design. Also, University of Wisconsin Fusion Technology Institute Report, UWFDM-1270. Available at: http://fti.neep.wisc.edu/pdf/fdm1270.pdf
R. Raffray, L. El-Guebaly, S. Malang, and X. Wang, “Attractive Design Approaches for a Compact Stellarator Power Plant” Fusion Science & Technology, 47, No. 3, 422 (2005).
J. Lyon, L.P. Ku, P. Garabedian, L. El-Guebaly, and L. Bromberg, “Optimization of Stellarator Reactor Parameters,” Fusion Science & Technology, 47, No. 3, 4414 (2005).
R. Raffray, S. Malang, L. El-Guebaly, and X. Wang, “Ceramic Breeder Blanket for ARIES-CS,” Fusion Science & Technology, 48, No. 3, 1068 (2005).