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

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• 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

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• 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.