Benefits of Radial Build Minimization and Requirements Imposed on ARIES Compact Stellarator Design...

Benefits of Radial Build Minimization and Requirements

Imposed on ARIES Compact Stellarator Design

Benefits of Radial Build Minimization and Requirements

Imposed on ARIES Compact Stellarator Design

Laila El-Guebaly (UW),

R. Raffray (UCSD), S. Malang (Germany),

J. Lyon (ORNL), L.P. Ku (PPPL)

and the ARIES Team

16th TOFE Meeting

September 14 - 16, 2004

Madison, WI

2

• 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.

Objectives

3

• Minimum radial standoff controls COE, unique feature for stellarators.

• Compact radial build means smaller R and lower Bmax

smaller machine and lower cost.

• All components provide shielding function:– Blanket protects shield

– Blanket & shield protect VV

– Blanket, shield & VV protect magnets

• Blanket offers less shielding performance than shield.

• Could design tolerate shield-only at min (no blanket)?

• What would be the impact on T breeding, overall size, and economics?

Background

Vac

uu

m V

esse

l

Sh

ield

FW

/ B

lan

ket

Mag

net

Permanent Components

4

New Approach for Blanket & Shield Arrangement

WC-Shield

Blanket

Magnet

Plasm

a

min

Shield/VV

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Xn through nominal blanket & shield

Xn at min

(magnet moves closer to plasma)

Plasma

Shield/VV

Blanket

Magnet

3 FP Configuration

5

Shield-only Zone Covers ~8% of FW Area

Beginning of FieldPeriod

Middle of FieldPeriod

3 FP Configuration

= 0

= 60

6

Breeder Multiplier Structure FW/Blanket Shield VVCoolant Coolant Coolant

ARIES-CS:Internal VV:

Flibe Be FS Flibe Flibe H2O

LiPb – SiC LiPb LiPb H2O

LiPb* – 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

SPPS:External VV:

Li – V Li Li He

Breeding Blanket Concepts

_________________________* With or without SiC inserts.

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Peak n Wall Loading 3* MW/m2

Overall TBR 1.1 (for T self-sufficiency)

Damage Structure 200 dpa - advanced FS

(for structural integrity) 3% burn up - SiC

Helium Production @ VV 1 appm (for reweldability of FS)

HT S/C Magnet (@ 15 K): Fast n fluence to Nb3Sn (En > 0.1 MeV) 1019 n/cm2

Nuclear heating 5 mW/cm3

Dose to polyimide insulator 1011 rads dpa to Cu stabilizer 6x10-3 dpa

Machine Lifetime 40 FPY

Availability 85%

Radial Builds have been DefinedUsing Same Design Criteria

___________* 4.5 MW/m2 for solid breeder concept.

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• 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.

Breeding Performance

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0 10 20 30 40 50 60 70

FW/Blanket Thickness (cm)

Flibe

LiPb/SiC

LiPb/FS

Li/FS

Flibe

LiPb/SiC

LiPb/FS

Li/FSSB

SB

Thick blanket; no structure; no multiplier Actual Design

0.8

1.0

1.2

1.4

1.6

1.8

2.0

1.1 1.2 1.3Neutron Energy Multiplication

Li4SiO

4

Li

Li2O

FLiBe

Li2TiO

3

Li17

Pb83

- nat

Li2ZrO

3LiAlO2

Li17

Pb83

- 90%Li6

9

Representative Radial Build(LiPb/FS/He System; Internal VV)

SO

L

Vac

uu

m V

esse

l

FS

Sh

ield

Ga p

Thickness(cm)

FW

Gap

+ T

h. I

nsu

lato

r

Win

din

g P

ack

Pla

sma

54.8 2 ≥ 232 312.228

≥ 149 cm| |

SO

L

Vac

uu

m V

esse

l

Bac

k W

all

Gap

Thickness(cm)

Gap

+ T

h. I

nsu

lato

r

Coi

l Cas

e &

In

sula

tor

Win

din

g P

ack

Pla

sma

52 247 312.228

| |C

oil C

ase

& I

nsu

lato

rmin = 118 cm

ShieldOnlyZones@ min

Bla

nk

et(L

iPb

/FS

/He)

47

11W

C S

hie

ld

Blanket& Shield

Zones Bac

k W

all

91

Gap

FW

4.8

Ext

ern

al S

tru

ctu

reE

xter

nal

Str

uct

ure

18

18

Blanket

Magnet

Plasm

a

min

Shield/VV

10

(m)ARIES-CS:

Internal VV: Blanket/Shield/VV/Gaps Plasma – Mid CoilFlibe/FS/Be 1.07 (min) 1.32 (min)

LiPb/SiC 1.15 1.40

LiPb/FS/He 1.24 1.49

Li4SiO4/Be/FS/He 1.30 (max) 1.55 (max)

External VV: Blanket/Shield/GapsLiPb/FS/He/H2O 1.22 1.47

LiPb/FS/He 1.60 1.85

Li/FS/He 1.79 (max) 2.04 (max)

SPPS*: External VV:

Li/V 1.20 1.96

–––––––––––––––––––––––– * 15 cm SOL, 36 cm half winding pack, 15 cm thick cryostat, and 8 cm wide shield-magnet gap.

Nominal Radial Standoff Varies Widely with Blanket Concept

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min (m)

ARIES-CS:Internal VV: WC-Shield/VV Plasma – Mid Coil

Flibe/FS/Be 0.86 (min) 1.11 (min)

LiPb/SiC 0.89 1.14

LiPb/FS/He 0.93 1.18

Li4SiO4/Be/FS/He 1.04 (max) 1.29 (max)

External VV: WC-ShieldLiPb/FS/He/H2O 0.95 1.20

LiPb/FS/He 0.93 1.18

Li/FS/He 0.91 1.16

SPPS: External VV:

Li/V – –

min Varies within 20 cm with blanket Concept

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Comparison Between Radial Builds

• 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 avoid breeders incompatible with water (such as Li).

0

50

100

150

200

Flibe/FS LiPb/SiC LiPb/FS SB/FS Li/FSLi/V

SPPS

SPPS

0

50

100

150

200

Flibe/FS LiPb/SiC LiPb/FS SB/FS Li/FSLi/V

SPPS

SPPS

Nominal Blanket/Shield Shield-only Zones

Helium Helium

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• Benefits:– Compact radial standoff– Small R and low Bmax

– 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.

New Shielding Approach Introduces Design Issues

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Key Parameters for System Analysis

Flibe/FS/Be LiPb/SiC LiPb/FS SB/FS/Be Li/FS

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 (Mn) 1.2 1.1 1.15 1.3 1.13

Thermal Efficiency (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 ofmin, Mn, and th on COE

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Well Optimized Radial Build Contributed to Compactness of ARIES-CS

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||

2 FP7.5 m

3 FP8.25 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.

198219872000199620002004

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• 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.

Conclusions

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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

Companion Presentations

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Magnet Design

Plasma/Blanket/Shield/VV

Insulator - 0.2 cm

Winding Pack-I - 17 cm

Winding Pack-II - 14 cm

Insulator - 0.2 cm

External Structure - 18 cm

Magnet Homogeneous Composition:45% 316-SS (gray)50% winding packs (orange/black)5% GFF polyimide (white)

MT Winding Pack-I:12.7% MgB2

45.5% Cu15.5% He @ 15 k17.3% 316-SS 9.0% GFF poly.

LT Winding Pack-II: 9.6% NbTi54.1% Cu21.8% LHe @ 4 k 5.5% 316-SS 9.0% GFF poly.

MT WP-I @ 15 K

LT WP-II @ 4 K

Coil Case - 2 cm

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QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

3 FP ConfigurationR = 8.25 ma = 1.85 m

2 FP ConfigurationR = 7.5 ma = 2 m

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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 Structure10% He Coolant75% Borated Steel Filler

VV 28% FS Structure49% Water23% Borated Steel Filler

LiPb/FS/He Composition

_________# Without SiC inserts.* FS and He contents will be adjusted later.