Benefits of Radial Build Benefits of Radial Build Minimization and Requirements Minimization and Requirements Imposed on ARIES Compact Imposed on ARIES Compact Stellarator Design Stellarator Design Laila El-Guebaly (UW), R. Raffray (UCSD), S. Malang (Germany), J. Lyon (ORNL), L.P. Ku (PPPL) and the ARIES Team 16 th TOFE Meeting September 14 - 16, 2004 Madison, WI
Objectives • Define radial builds for proposed blanket concepts. • Propose innovative shielding approach that minimizes radial standoff. • Assess implications of new approach on: – Radial build – Tritium breeding – Machine size – Complexity – Safety – Economics. 2
Background • Minimum radial standoff controls COE, unique feature for stellarators. • Compact radial build means smaller R and lower B max fi smaller machine and lower cost. Vacuum Vessel • All components provide shielding function: FW / Blanket Magnet Shield – Blanket protects shield – Blanket & shield protect VV – Blanket, shield & VV protect magnets Permanent Components • Blanket offers less shielding performance than shield. • Could design tolerate shield-only at D min (no blanket)? • What would be the impact on T breeding, overall size, and economics? 3
New Approach for Blanket & Shield Arrangement Magnet Shield/VV Shield/VV Blanket 3 FP Plasma Blanket Plasma Configuration D min WC-Shield Magnet Xn at D min Xn through nominal (magnet moves closer to plasma) blanket & shield 4
Shield-only Zone Covers ~8% of FW Area 3 FP Configuration Beginning of Field Period f = 0 f = 60 Middle of Field Period 5
Breeding Blanket Concepts Breeder Multiplier Structure FW/Blanket Shield VV Coolant Coolant Coolant ARIES-CS : Internal VV: Flibe Be FS Flibe Flibe H 2 O LiPb – SiC LiPb LiPb H 2 O LiPb * – FS He/LiPb He H 2 O Li 4 SiO 4 Be FS He He H 2 O External VV: LiPb * – FS He/LiPb He or H 2 O He Li – FS He/Li He He SPPS: External VV: Li – V Li Li He _________________________ * With or without SiC inserts. 6
Radial Builds have been Defined Using Same Design Criteria Peak n Wall Loading 3 * MW/m 2 Overall TBR 1.1 (for T self-sufficiency) Damage Structure 200 dpa - advanced FS 3% burn up - SiC (for structural integrity) Helium Production @ VV 1 appm (for reweldability of FS) HT S/C Magnet (@ 15 K): 10 19 n/cm 2 Fast n fluence to Nb 3 Sn (E n > 0.1 MeV) mW/cm 3 Nuclear heating 5 Dose to polyimide insulator 10 11 rads 6x10 -3 dpa dpa to Cu stabilizer Machine Lifetime 40 FPY Availability 85% ___________ * 4.5 MW/m 2 for solid breeder concept. 7
Breeding Performance Actual Design Thick blanket; no structure; no multiplier 2.0 1.4 Li 1.2 Tritium Breeding Ratio 1.8 Li/FS Li 17 Pb 83 - 90%Li6 SB 1.0 LiPb/FS 1.6 Local TBR Li 17 Pb 83 - nat 0.8 Flibe 1.4 Li 2 O 0.6 FLiBe 1.2 LiPb/SiC 0.4 Li 2 TiO 3 Li 4 SiO 4 LiPb/FS 1.0 Flibe 0.2 Li 2 ZrO 3 SB Li/FS LiAlO 2 LiPb/SiC 0.8 0.0 1.1 1.2 1.3 0 10 20 30 40 50 60 70 Neutron Energy Multiplication FW/Blanket Thickness (cm) • Local TBR approaches 1.25. • Blankets sized to provide 1.1 overall TBR based on 1-D analysis combined with blanket coverage fraction. • 3-D analysis should confirm key parameters. 8
& Shield Blanket Zones D min Shield/VV Magnet P l a s m a B l n a k e t Plasma | SOL 5 4.8 FW Representative Radial Build Plasma Blanket (LiPb/FS/He System; Internal VV) 47 (LiPb/FS/He) | SOL 5 4.8 FW Back Wall 9 1 a p G D ≥ 149 cm 47 WC Shield 9 FS Shield D min = 118 cm 32 11 Back Wall Gap 2 Gap 2 Vacuum Vessel 28 28 Vacuum Vessel ≥ 2 Gap + Th. Insulator Gap + Th. Insulator 2 2.2 2.2 Coil Case & Insulator Coil Case & Insulator 31 31 Winding Pack Winding Pack | | 18 18 External Structure External Structure Thickness @ D min Thickness Shield Zones Only (cm) (cm)
Nominal Radial Standoff Varies Widely with Blanket Concept D (m) ARIES-CS : Blanket/Shield/VV/Gaps Plasma – Mid Coil Internal VV: Flibe/FS/Be 1.07 (min) 1.32 (min) LiPb/SiC 1.15 1.40 LiPb/FS/He 1.24 1.49 Li 4 SiO 4 /Be/FS/He 1.30 (max) 1.55 (max) Blanket/Shield/Gaps External VV: 1.22 LiPb/FS/He/H 2 O 1.47 LiPb/FS/He 1.60 1.85 Li/FS/He 1.79 (max) 2.04 (max) SPPS * : External VV: 1.96 Li/V 1.20 –––––––––––––––––––––––– * 15 cm SOL, 36 cm half winding pack, 15 cm thick cryostat, and 8 cm wide shield-magnet gap. 10
D min Varies within 20 cm with blanket Concept D min (m) ARIES-CS : WC-Shield/VV Plasma – Mid Coil Internal VV: Flibe/FS/Be 0.86 (min) 1.11 (min) LiPb/SiC 0.89 1.14 LiPb/FS/He 0.93 1.18 Li 4 SiO 4 /Be/FS/He 1.04 (max) 1.29 (max) WC-Shield External VV: LiPb/FS/He/H 2 O 0.95 1.20 LiPb/FS/He 0.93 1.18 Li/FS/He 0.91 1.16 SPPS: External VV: Li/V – – 11
Comparison Between Radial Builds 200 200 Nominal Blanket/Shield Shield-only Zones Minimum Plasma to Mid-coil Distance (cm) SPPS SPPS Plasma to Mid-coil Distance (cm) 150 150 100 100 50 50 0 0 Li/V Li/V Flibe/FS LiPb/SiC LiPb/FS SB/FS Li/FS Flibe/FS LiPb/SiC LiPb/FS SB/FS Li/FS SPPS SPPS Helium Helium • Flibe system offers most compact radial build, but Be raises safety and economic concerns. • He coolant occupies 10-30 cm of radial standoff. • Water is effective shielding material for VV fi avoid breeders incompatible with water (such as Li). 12
New Shielding Approach Introduces Design Issues • Benefits : – Compact radial standoff – Small R and low B max – Low COE. • Challenges (to be addressed in Phase II of study): – Integration of shield-only zones with surrounding blanket. – Incorporation of decay heat removal loop for WC-shield. – Handling of massive WC-shield during maintenance. 13
Key Parameters for System Analysis Flibe/FS/Be LiPb/SiC LiPb/FS SB/FS/Be Li/FS D min 1.11 1.14 1.18 1.29 1.16 Overall TBR 1.1 1.1 1.1 1.1 1.1 Energy Multiplication (M n ) 1.2 1.1 1.15 1.3 1.13 Thermal Efficiency ( h th ) ~45% 55-60% ~45% ~45% ~45% FW Lifetime (FPY) 6.5 6 5 4.4 7 System Availability ~85% ~85% ~85% ~85% ~85% Integrated system analysis will assess impact of D min , M n , and h th on COE 14
Well Optimized Radial Build Contributed to Compactness of ARIES-CS m ARIES-ST Spherical Torus 8 3.2 m Stellarators | 6 | 2004 2000 2000 1987 1996 1982 4 ARIES-CS ARIES-AT Tokamak 3 FP 2 FP ASRA-6C HSR-G 5.2 m 8.25 m 7.5 m SPPS UWTOR-M 2 20 m FFHR-J 18 m 14 m 24 m 10 m 10 15 20 25 5 0 Average Major Radius (m) Major radius more than halved by advanced physics and technology, dropping from 24 m for UWTOR-M to 7-8 m for ARIES-CS and approaching R of advanced tokamaks. 15
Conclusions • Innovative shielding approach has been developed for ARIES-CS. • Combination of shield-only zones and non-uniform blanket represents best option for ARIES-CS. • Solutions for challenges facing proposed shielding approach will be developed in Phase-II of study. • Means of dimension control along with advances in physics and technology helped ARIES-CS achieve the compactness that other stellarators had not been able to achieve before. • Positive trends in physics and engineering position compact stellarators for bright future. 16
Companion Presentations Poster on Wednesday @ 1:30 - 3:30 PM: Initial Activation Assessment for ARIES Compact Stellarator Power Plant L. El-Guebaly, P. Wilson, D. Paige and the ARIES Team Oral on Tuesday @ 10:30 - 12 AM: Evolution of Clearance Standards and Implications for Radwaste Management of Fusion Power Plants L. El-Guebaly, P. Wilson, D. Paige and the ARIES Team 17
Magnet Design Plasma/Blanket/Shield/VV Coil Case - 2 cm Insulator - 0.2 cm MT WP-I @ 15 K Winding Pack-I - 17 cm LT WP-II @ 4 K Winding Pack-II - 14 cm Insulator - 0.2 cm External Structure - 18 cm MT Winding Pack-I: LT Winding Pack-II: Magnet Homogeneous Composition: 12.7% MgB 2 9.6% NbTi 45% 316-SS (gray) 45.5% Cu 54.1% Cu 50% winding packs (orange/black) 15.5% He @ 15 k 21.8% LHe @ 4 k 5% GFF polyimide (white) 17.3% 316-SS 5.5% 316-SS 9.0% GFF poly. 9.0% GFF poly. 18
2 FP Configuration 3 FP Configuration R = 8.25 m R = 7.5 m a = 1.85 m a = 2 m 19
LiPb/FS/He Composition Component Composition FW 31% FS Structure 69% He Coolant Blanket # 90% LiPb with 90% enriched Li 3% FS Structure 7% He Coolant Back Wall 80% FS Structure 20% He Coolant WC Shield * 90% WC Filler 3% FS Structure 7% He Coolant FS Shield 15% FS Structure 10% He Coolant 75% Borated Steel Filler VV 28% FS Structure 49% Water 23% Borated Steel Filler _________ # Without SiC inserts. * FS and He contents will be adjusted later. 20
Recommend
More recommend
