Status of 3-D Analysis, Neutron Streaming through Penetrations,

and LOCA/LOFA Analysis

Status of 3-D Analysis, Neutron Streaming through Penetrations,

and LOCA/LOFA Analysis

L. El-Guebaly, M. Sawan, P. Wilson, D. Henderson, A. Ibrahim,

G. Sviatoslavsky, B. Kiedrowski, T. Tautges, C. Martin

Fusion Technology InstituteUW - Madison

Contributors:X. Wang, S. Malang (UCSD)

ARIES-CS Project MeetingOctober 4 - 5, 2006

PPPL

2

Final Radial Build(http://fti.neep.wisc.edu/aries-cs/builds/build.html)

(5.3 MW/m2 Peak NWL)

Thickness(cm)

| |Thickness

(cm)

Non-uniformBlanket

&Shield

@ min

FullBlanket

& Shield

Replaceable FW/Blkt/BW

≥ 179 cm

SO

L

Vac

uu

m V

esse

l

FS

Sh

ield

(per

man

ent)

Ga p

3.8

cm F

W

Gap

+ T

h. I

nsu

lato

r

Win

din

g P

ack

Pla

sma

5 >2 ≥232 19.42.228

Coi

l Cas

e &

In

sula

tor

5 cm

Bac

k W

all

28

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

He

& L

iPb

Man

ifol

ds

Vac

uu

m V

esse

l

Ga p

Gap

+ T

h.

Insu

lato

rC

oil C

ase

& I

nsu

lato

r

Win

din

g P

ack

Pla

sma

2 2 19.42.228

| |min = 130.7 cm

Str

ong

Bac

k

28

SO

L

Bac

k W

all

5 14 5

FW

3.8

FS

Sh

i eld

-I(r

epla

c eab

le)

34

WC

Sh

ield

(per

man

ent)

Str

ong

Bac

k

25

Bla

nk

et

3

Status of 3-D TBR Analysis

Purpose: compute overall TBR and Mn

CAD model received from UCSD on 9/19/06 including:FW/Blanket/BWShieldManifoldsVVMagnetDivertorNo penetrations!

Essential components for TBR and Mn will be included in 3-D model:FW/Blanket/BWShieldManifolds (continuous)DivertorECH ducts (to be added by UW).

4

Status of 3-D TBR Analysis (Cont.)

• Complex 3-D problem, requiring many time-consuming iterations.• UW had difficult time transferring UCSD model into ACIS.• UW manipulated UCSD geometry to merge properly even though Xueren

tried improving accuracy settings in Pro/E.• Clean model shows no sign of overlapping. 3-D analysis in progress.• Future ARIES modeling work should be produced in ACIS*.

___________* Commercial solid modeling engine underlying CGM and CUBIT, analogous to what's under Pro/E.

5

Neutron Streaming through Penetrations

• Neutron streaming through penetrations compromises shielding performance.• ARIES-CS 7 types of penetrations:

– 198 He tubes for blanket (32 cm ID)– 24 Divertor He access pipes (~30 cm ID)– 30 Divertor pumping ducts (42 x 120 cm each)– 12 Large pumping ducts (1 x 1.25 m each)– 3 ECH ducts (24 x 54 cm each).– 6 main He pipes - HX to/from blanket (72 cm ID each)– 6 main He pipes - HX to/from divertor (70 cm ID each)

• Potential solutions:– Local shield behind penetrations– He tube axis oriented toward lower neutron source– Penetration shield surrounding ducts– Replaceable shield close to penetrations– Rewelding of VV and manifolds avoided close to penetrations– Bends included in some penetrations.

√√

6

Streaming through Blanket He Tubes(9/15/05 Presentation)

• 198 He tubes (30 cm ID) connect manifolds to blanket modules.

• 2-D results:– High damage at tube wall– High damage at VV and magnet

behind tubes.

• Solutions:– Orient tube toward lower n source– Avoid welding near tube wall– Replaceable shield close to tube– Local shield behind tube to protect

VV and magnet.

Back Wall

5 cm FS

32 cm OD

10 cm Thick WC10 cm Thick WC

VV & Magnets

Weld

25 cm Local Shield

7

Streaming through Divertor System

24 He access pipes (~30 cm ID)

30 pumping ducts (42 x 120 cm each)

8

Streaming through Divertor Pumping Ducts

Thickness(cm)

20 cm Divertor System

Local shield behind ducts needed to protect VV & magnet

Man

ifol

ds

SO

L Vac

uu

m V

esse

l

FS

Sh

ield

Ga p

Gap

+ T

h. I

nsu

lato

r

Win

din

g P

ack

Pla

sma

20 >2 ≥232 19.42.228

Coi

l Cas

e &

In

sula

tor

Ba c

k W

all

6625| | 35

He

& L

iPb

Ma n

ifo l

ds

Ext

ern

al S

tru

ctu

re

Bla

nk

et

Gap

7.512.5T

arge

ts /

Baf

fles

30 c

m I

D35

cm

OD

Divertor He Access Pipe

2.5 cm gap

WC Shield

Divertor Pumping Duct

42

Replaceable shield around pumping duct

9

Effect of Streaming through Divertor He Access Pipes

NWL near pipes= 0.5 - 1 MW/m2.

2-D model of pipe estimated:• dpa at shield• He production at manifolds• He production at VV• Fast neutron fluence at WP• Flux behind pipe• dpa & He production along pipe wall.

3-D streaming analysis is underway using Attila code.

He

Acc

ess

Pip

e

Shield

Blanket

Manifolds

Divertor

Plasma

VV

Str

uctu

re

WP

Inte

rcoi

l

10

Part of Shield Surrounding Pipe Should be Replaceable

2.2

He

Acc

ess

Pip

e

Shield

Blanket

Manifolds

Divertor

Plasma

VV

Str

uctu

reWP

Inte

rcoi

l

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 20 40 60 80 100

Distance from Pipe Centerline (cm)

Pipe/Gap

11

Part of Manifolds Surrounding Pipe Cannot be Rewelded

48H

e A

cces

s P

ipe

Shield

Blanket

Manifolds

Divertor

Plasma

VV

Str

uctu

reWP

Inte

rcoi

l

10-1

100

101

102

0 20 40 60 80 100

Distance from Pipe Centerline (cm)

12

Part of VV Surrounding Pipe Cannot be Rewelded

43H

e A

cces

s P

ipe

Shield

Blanket

Manifolds

Divertor

Plasma

VV

Str

uctu

reWP

Inte

rcoi

l

10-1

100

101

102

0 20 40 60 80 100

Distance from Pipe Centerline (cm)

13

30-40 cm Inter-coil Structure around Pipe Protects Sides of WP

230H

e A

cces

s P

ipe

Shield

Blanket

Manifolds

Divertor

Plasma

VV

Str

uctu

reWP

Inte

rcoi

l

10-1

100

101

102

0 20 40 60 80 100

Distance from Pipe Centerline (cm)

14

High Flux Behind Pipe Calls for Local Shield to Protect Externals

104H

e A

cces

s P

ipe

Shield

Blanket

Manifolds

Divertor

Plasma

VV

Str

uctu

reWP

Inte

rcoi

l

10-1

100

101

102

103

104

0 20 40 60 80 100

Distance from Pipe Centerline (cm)

15

Pipe Wall

Front part of pipe wallshould be replaceable

Pipe wall is not reweldable Replace pipe with divertor

Permanent

Replaceable

10-2

10-1

100

101

0 50 100 150 200

Distance Along Pipe Wall (cm)

100

101

102

103

0 50 100 150 200

Distance Along Pipe Wall (cm)

DivertorSurface

DivertorSurface

16

Recommendations

Replaceable Shield Not Reweldable Local Shield

FS

Sh

ield

Man

ifol

ds

SO

L

Vac

uu

m V

esse

l

Ga p

Gap

+ T

h. I

nsu

lato

r

Win

din

g P

ack

Pla

sma

20 >2 ≥232 19.42.228

Coi

l Cas

e &

In

sula

tor

Ba c

k W

all

6625| | 35

He

& L

iPb

Man

ifo l

ds

Ext

ern

al S

tru

ctu

re

Bla

nk

et

Gap

7.512.5T

arge

ts /

Baf

fles

30 c

m I

D35

cm

OD

Replaceable Divertor He Access Pipe

2.5 cm gap

Divertor Pumping Duct

42

30-40 cm

17

Ongoing 3-D Streaming Analysis Using Attila Code

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Purpose: Determine dimensions of replaceable shield, non-reweldable manifolds and VV, and local shield.

18

Alternate Pipe Design(S. Malang)

19

Comments on Alternate Pipe Design

• Shielding ring and block do not solved streaming problem entirely:– 10 cm thick WC shielding ring is insufficient to protect pipe wall, bulk shield, and manifolds Parts around pipe should be replaceable and cannot be rewelded.– Shielding block will not attenuate flux behind pipes by 4 orders of magnitude Local shield behind pipe is still needed.

• Sizable WC shield added:Mass / pipe (ton) Alternate Design Baseline Design

Shielding Ring ~1.6 ---Shielding Block ~1 ---2.5 cm FS Pipe Wall 0.6 0.4

Total mass - 24 pipes ~77 ton ~10 ton

20

LOCA / LOFA Analysis(2.6 MW/m2 Ave. NWL; 0.5 MW/m2 Surface Heat Load)

Initial temperatures at onset of LOCA/LOFA:FW 500 oC Shield & Manifolds 450 oCSiC 550 oC VV 100 oCBack wall 450 oC LiPb average temp 625 oC

Assumptions: Plasma on for 3 s; Instantaneous loss of coolant.

Blanket Shield Vacuum Vessel

First WallTinit = 500 C

SiC LinerTinit = 550 C

Back WallTinit = 450 C

Shield & ManifoldTinit = 450 C

Vacuum VesselTinit = 100 C

Ga

p

Rad

ius

= 2

.0 m

H20

H20

H20

Manifold

LiPBTinit = 625 C

21

Uniform Blanket and Shield (He & LiPb LOCA in all Modules; H2O LOFA in VV)

= 0.3 all surfaces

Max temp = 753 oC Max temp = 700 oC

= 0.5 for SiC

22

Non-uniform Blanket and Shield (He & LiPb LOCA in all Modules; H2O LOFA in VV)

= 0.3 all surfaces

Max temp = 762 oC Max temp = 720 oC

= 0.5 for SiC

23

Summary and Conclusions

• 3-D TBR and streaming analyses are underway.

• No shielding ring or block should be included in divertor He access pipes.

• Ongoing 3-D streaming analysis will determine size of replaceable shield and non-reweldble manifolds/VV around pipes.

• More realistic LOCA/LOFA assumptions help reduce temperature during accident.