1

第15回 ITPA（SOL/DIV）の概要
Material migration, Be erosion, W R&D
ITER-like Wall （JET）
大阪大学 大学院工学研究科 上田良夫
PWI 合同研究会
平成23年 7月20日- 22日
筑波大学プラズマ研究センターシンポジューム
プラズマ物理クラスター スクレープオフ層とダイバー タ物理サブクラスター(第1回会合)
炉工学クラスター ブランケット サブクラスター(第2回会合)
双方向型共同研究会合「ガンマ１０装置における炉壁材料の損耗・再堆積の研究とそのダイバータ開発戦略における位置づけ」

2Migration and Be erosion

Material migration
再 B
堆 e
積第の一
モ壁デ損
リ 耗ン とグ

intended presentation on modeling of ITER wall erosion/deposition
medium scale modelling of ITER main chamber eorison/redeposition
WallDYN applied to JET
13C injection experiments in AUG and their modeling using DIVIMP
and ASCOT, with the focus on the main chamberLong term tracer experiments for erosion / redeposition pattern on thefirst wallBe erosion
New data on Be erosion obtained with QSPA plasma guns at ITERlike ELMs simulations
Erosion/deposition balance in Be seeded high flux D discharges

ITER Be wall – BM erosion
FLFS close to 2nd separatrix =>First PFC life time estimates assuming
limiter-like contact on outboard BM11

BM11BM 15

Be+ low Z- high erosion• Blanket module (BM) shapes optimized forheat loads (P.C.Stangeby)
12.05.2011

Aim – predictive modelling ofITER, including first wall life time

D.Borodin | PFMC-13, Rosenheim | Forschungszentrum Jülich

No 4

3D MC impurity transport code ERO
Background Plasma

Cx+,Bex+,…
CDz0,+

re-eroded/
reflected particles

B
EC, Be, …
CD4

Input:
ne, Te,i,geometry

PFC (substrate Be, C, W, Mo, …)
Local transport:

ionisation, dissociation
friction (Fokker-Planck), thermal force
Lorentz forcecross-field diffusion
12.05.2011

Plasma-surface interaction:

physical sputtering/reflection
chemical erosion (CD4)(re-)erosion and (re-)deposition
HMM and SDTrimSP surface models

D.Borodin | PFMC-13, Rosenheim | Forschungszentrum Jülich

No 5

Be sputtering yields – extreme assumptions
Be by D+ sputtering

Be by D+ sputtering„ERO-max“„ERO-min“

Only the ‘calculated’ data are included!
1) “maximum” – static TRIM + MD2) “minimum” – SDTrimSP with 50% of D(reasonable limit)

Experimental data too much scattered!
1) Large deviations: no sense to analyse
shape of curves
2) Various effects are difficult to separate

Normal incidence! Angle dependence should be taken into the account!
12.05.2011

D.Borodin | PFMC-13, Rosenheim | Forschungszentrum Jülich

No 6

UCSD
University of California San Diegosurface morphology of PISCES-B targets:bias dependence

pure D exposure, < 330K: jD = x·1022 Dx+/cm2 SEM under 40°-50V bias (tmsBe19),
Y= 0.23% per ion-100V bias (tmsBe17)
Y= 0.45% per ion-170V bias (tmsBe3back)Y= 0.63% per ion

ITPA_Sputtering of Be.ppt, © Thomas Schwarz-Selinger, 15. May 2011

Sputter yields assumptions and net erosion
BM11, ‘HDC’: net erosion (deposition) profile at y=-187mm
0.01

Layer evolution
layer evolution [mm/h][mm/h]

04200 ITER shots-0.01

LIM predictions-0.02

1500 ITER shots
-0.03
-0.04

1100 ITER shots

-0.05
-0.06

ERO-max (0.081mm/h)
ERO-min (0.021mm/h)
Eck2002(LIM) (0.062mm/h)-0.07

LIM predictions

-0.08
-600

-400

-200

0x (toroidal) [mm]200400600

In most pessimistic case life time about 30% less than in earlier LIM predictions
12.05.2011

D.Borodin | PFMC-13, Rosenheim | Forschungszentrum Jülich

No 8

Be migration と Be erosionのまとめ
 EROコードとLIMコードによるシミュレーション結果は、おおむね一致
 特に損耗が懸念される場所（BM11）における損耗による寿命（Be厚：1mm）は、4,200ショットから1,100ショットまで大きくばらつく（EROコード）。
 実験値の最大損耗量（IPPのデータ）を用いるとさらに寿命は短くなる（< 1,100 shot）
 ダイバータ交換の目安は3,000ショット程度
 少なくとも、これ以上の寿命が必要と考えられる

 実験においてスパタリング率に大きなばらつきが生じる理由
 表面形状の影響？
 コーン形状の影響→イオンの入射角に依存するので、実機で同様の表面形状が現れるかは不明

 フラックス影響？

910Tungsten R&D

W damage
タングステン（金属壁）の溶融挙動

Transient heat load tests on monolithic tungsten with high電子ビームによるELM模擬実験
repetition rates W melt experiments in tokamaks - （TEXTOR）
W melting and melt layer motion experiments in Pilot-PSI Melting of tungsten sample and metal first wall in LHD tungsten recrｙstallization after melting/erosion

Melting limit ~ 1MJ/m2

溶融限界（～1MJ/m2）より大幅に低い熱パルスでも、繰り返し照射により亀裂が生じる

Effect of He pre-exposure on melting
 Helium pre-exposure of tungsten surface
 Exposure to pulsed plasma (combined with steady-state plasma)

W target pre-exposed
1800 C, 200 s

2x 0.3MJ.m-2

Reason for suchsignificant melting nottotally clear
Consistent observation,
biasing increases theprobability of melting

G. De Temmerman

ITPA SOL/Div meeting, Helsinki, May 2011

Accidental Melting (A-CMod)Stainless steel first wall panels weremelted locally.
Accidental Melting (LHD)B

 In these cases,
melted layer
motions were
upward against
gravity.
 Directions of theirmotion wereroughly
perpendicular to B
direction.

B

1618 May 2011, S. Masuzaki

First observation of W-fuzz erosion by arcing infusion device
before exp.

fuzzafter exp.

normal10mmExfoliation of the W-fuzz

Residual fuzz

0.5 mm

10µm
17M.Tokitani et al, to be submitted to NF
18 May 2011, S. Masuzaki

Cross section view of W-fuzz made in NAGDIS
Obs. by N. Yoshida(Kyusyu univ.)
Arc trail

FIB•The arc trail were cut by FIB (FocusedIon Beam) milling process.
•The cross sectional view of the arc
trail, the base W was not eroded by arc.
S. Kajita

18

18 May 2011, S. Masuzaki

タングステンR&Dのまとめ
 表面損傷と溶融層挙動の研究成果
 実験室実験結果（低エネルギー繰り返しパルス熱負荷、パルス熱負荷＋定常熱負荷）
 実機での溶融実験（多くの装置で、Bに垂直な溶融層の運動を観測、A-CMod、TEXTOR、LHD）

 熱負荷と粒子負荷の相乗効果
 Heプラズマ照射とパルス熱負荷の同時照射時に表面の融点が下がる？（Pilot-PSI）

 実験室実験と実機実験との対応
 Fuzz上のアーキング（LHD）
 Fuzzの生成（A-CMod）
 この分野は、モデリングのベンチマーク実験という意味合いも含め特に重要である。

19

Experimental Program
for the Exploitation of theITER-Like Wall at JET
2011/2012

S. Brezinsek
For TFE1 and TFE2 leaders
S. Brezinsek 20 (47)

ITPA Div-SOL Meeting - Helsinki

19/05/2011

The Wall Combination for the DT Phase in ITER
Be wall and W divertor in JETITER

 Material combination for the first time used
 Replacement of the wall in one shutdown “Carbon-free” environment
 Reduced material migration to rem. areas
 Reduced tritium retention
 Loss of carbon as main radiator

JET Change in operational space Need for better plasma control
 Need for heat load mitigation schemes Need for semi-detached divertor
 Need for impurity-seeded plasmas

NBI upgrade in JET
 Parallel upgrade of neutral beam system
 Maximum power from 20 to 34 MW
 Maximum duration from 10 to 20 sS. Brezinsek 21 (47)

ITPA Div-SOL Meeting - Helsinki

19/05/2011

Plasma-Wall Interaction Issues
Important PWI questions for ITER will be addressed in JET with the ILW

Steady-state operation
 Be wall erosion and transport Be-W material mixing Be:D layer formation and retention
 Re-erosion of (mixed) layers
 Material Transport to remote areas
 W erosion and prompt depositionTransients Be/W Melt layer motion, lossand stability
 Metallic dust formation

S. Brezinsek 22 (47)

ITPA Div-SOL Meeting - Helsinki

19/05/2011

Program Sequence – ILW 2011/2012
Maximise operating time and optimise with respect to Headlines andITER priorities
JanFebMarAprMayJunJul2011
2012

C29

C29

C30a

C30a

SepOctNovDec

C28

C28C28C28C29

ShutdownC30c

1st plasma
MidAugust 2011

Pump-down
15th May2011C30bAug

R1

C28A R2 C28B R3 C28C R4a130d(80d)

Ohmic L-mode H-mode
(15d)

(10d)

C29R4b(7d)Restart blocks interleaved with Campaign C28 blocks
Controlled start with scientific supervision
C28-C29 (fixed timeline) and C30 (provisional plan)
C30 to be consolidated in Nov 2011 in a general planning meeting

S. Brezinsek 23 (47)

ITPA Div-SOL Meeting - Helsinki

19/05/2011

Campaign Overview
Campaigns

DurationTarget plasma

C28a

8 days- Initial Be and W erosion and migration

Ohmic

C28b

~15days- Fuel retention and migration in L-modes- Characterisation of L-mode at high andHigh & low shape L-mode +PIN=5MW/5s

low shape in all metal environment.
C28c~20 days- Initial studies of low power H-mode.
High & low shape H-mode +- Fuel retention and migration in low power PIN=12MW/5s
H-mode.

C29~46 days

- Development of capabilities and tools forhigh power operation.
- Fuel retention and migration in robust Hmodes

C30a~36 days

- Safely expanding the operating space
towards ITER relevant regimes at highpower.

C30bC30c~ 21 days~13 days

S. Brezinsek 24 (47)

- Physics issues in support of a the Be/W

High & low shape H-mode(2.5MA/2.7T) + PIN=15MW/8s
First hybrid at 2T, bN=3.
High & low shape H-mode(3.5MA/3.4T) + PIN=32MW/4s
Hybrid scenario up to 3T &bN=3.

wall exploitation.

Work within establishedsafe operating space- Preparation long term removal sample.

Robust H-mode one NIB

ITPA Div-SOL Meeting - Helsinki

19/05/2011

P. Coad , PFCM Rosenheim
2011
What about
the future ? : Marker coating for ILW
BeforeAfter

7µmBe/NiBe (or W)

erosionBe (or W)

Ni (or Mo)
interlayer

Be (or W/CFC)•

Be (or W/CFC)

Marker tiles–––––

2 full poloidal sets of divertor tiles
Outer poloidal limiter tiles
Inner wall guard limiter tiles
Dump plate tiles
Inner Wall Cladding tiles

W/MoFirst set of tiles will be removed in 2012 during short intervention