No 1 V. Philipps, SEWG Fuel retention, July 2010, Garching Joint TEXTOR, MAGNUM and PISCES experiments on retention in W and mixed W/C system V. Philipps,

No 1

V. Philipps, SEWG Fuel retention, July 2010, Garching

Joint TEXTOR, MAGNUM and PISCES experiments on retention in W and mixed W/C system

V. Philipps, M. Zlobinski

FZJ Jülich

1.D retention in bulk W, W coatings and mixed W/C systems under TEXTOR edge conditions, comparison with pure graphite samples under identical conditions

Te ( 20- 50 eV) , shifted Maxwellian energy distribution

D+ 100- 250 eV

2-4 % C, 1-2 % O: 280 – 700eV (C3+ , O3+)

Flux range: 1021- 5 x 10 22/m2s

Fluence: 5 – 10 x 1024/m2

2. W samples exposed in RF plasma (TOMAS) and GDC (PADOS)

3. Retention under Magnum (PILOT) exposure conditions

Also: exploration of spot laser desorption versus normal TDS

(for TEXTOR apllication)

No 2


WMo

C

LCFS (46cm)

Erosion dominated

Deposition dominated

Plasma near edge, highest D-fluence

Far SOL, deposition dominated

Polycrstalline Mo, W, high purity, (Good Fellow), EK98 graphite No annealing

Previous exposures of bulk W, Mo and C in TEXTOR

Decreasing flux λF ≈ 1.2 cm

No 3


Tangential view, WI light

0.5 50.5 100.5 150.5 200.5 250.5 300.5 350.5 400.5 450.5 500.5 550.5 600.5 650.5 700.5728.5

0.5

50.5

100.5

150.5

200.5

250.5

300.5

350.5

400.5

450.5

500.5

550.5568.5

Hα light side view

Spectroscopic side view observations

No 4


C Mo W0,0

5,0x1020

1,0x1021

1,5x1021

2,0x1021

2,5x1021R

eten

tion (D

/m2 )

Material

Retention in polished bulk W, Mo and EK98 graphite from upper exposed edge ( slow TDS)

Fluence : ≈ 10 25 D/m2 (from mapped edge diagnostic (under revision)

550K < Tmax < 650 K (limiter preheated to 550 K)

Unpublished

TDS 24 months after exposure, storage in air

No 5


MIT ITPA workshop and report

No 6


D retention in JET W-coatings

Recent retention measurements on W coated JET samples CMSII W layers with interlayer of Mo (2-3 µm)

before exposure

parallel orientation, 20-25 µm,before exposure

Samples :From C. RusetRomania ASSOCIATION EURATOM / MEdC

CFC (DMS780) without coating as referenceCFC with 10-15 µm and with 20-25 µm W layer

exposed under identical plasma conditionsfibre orientations: parallel and perpendicular

No 7


Side view:

Top view:

↓ tokamak outside ↓ (LFS)

I E

Limiter configuration

toroidal

radialpoloidal

toroidal

ion

dri

ft s

ide

ele

ctr

on

dri

ft s

ide

W layer: 10-15 µm

W layer: 20-25 µm

uncoatedCFC

uncoatedCFC

W layer: 10-15 µm

W layer: 20-25 µm

fibre orientation:perpendicularparallel

perp. ......

LCFS4-6

No 8


Exposure in TEXTOR

Surface temperature: Tstart (TC data) : 80- 100 CT rise during shot: 90- 110 C (spot pyrometer on limiter tip)→ Tmax< 500K

ohmic discharges 355 kA, <ne> = 3.4 . 1019 / m3,

0 1 2 3 4 5 60

1

2

3

4

0

-100

-200

-300

-400

I p / kA

<n e>

/ 10

19 /

m3

t / s

43 shots 0.5 cm behind LCFS (6 shots 1.3 cm behind=

215 plasma second, 172 flattop

Fluence estimation:Hα light integrationHe beam edge diagnosticTemperature excursion with heat flux model

I ETop View

0.5 – 1 x 1025 D/m2

( to be improved)

No 9


I E

Limiter after exposure

erosion dominated zone

deposition dominated zone with layer formation

TDS LID

TDS

Laser desorption

No 10


LID-QMS Spectra for Graphite

QM

S-D

elta

-Sig

nal

/ V

QM

S S

igna

l / V

QM

S S

igna

l / V

m/q / amu/e

before laser pulse

after laser pulse

desorption spectrum = „after“ – „before“

2 3 4 12 16 18 20 28 44

H2 D2 C CH4 CD4 CO CO2D N2

HD H2O

U in V►►► number of atoms via calibration factor

ALT 2/29 tile: 6.10.2005 –

6.3.2008 inside TEXTOR

QMS

thick deposition5 . 1022 D/m2

1023 H/m2

2 . 1021 D/m2

4 . 1021 H/m2

4 . 1021 D/m2

9 . 1021 H/m2

5 . 1021 D/m2

7 . 1021 H/m2

4 . 1021 D/m2

6 . 1021 H/m2

No 11


Heating of a Quartz tube form outside

Lock system to introduce samples without breaking vacuum

Vacuum < 10-8 mbar

Background heating measurement before and after TDS

TDS measurements

No 12


-2 0 2 4 6 8 100

50

100

150

200

250

Tem

per

atu

re (

C)

Time(s)

R=46.5

44 similar shots

Spot pyrometer on the graphite samples

2D IR camera in parallel

0 1 2 3 4 5 60

1

2

3

4

0

-100

-200

-300

-400

I p / k

A

<n e>

/ 1

019 /

m3

t / s

Light reflection

No 13


0 200 400 600 800 1000

0

1x1019

2x1019

3x1019

4x1019

5x1019

6x1019

7x1019

D-r

ele

as

e (

Ato

ms

/m2 s

)

Temp (C)

M3M4Datoms

TDS on JET W samples

1: 20-25 μm

2: 10-15μm

Perp fiber

1.3 K/sec

Storage of samples in vacuum

TDS 3 weeks after exposure

20-25 μm

10-15 μm

1: 1.76 1022 D/m2

2: 1.94 1022 D/m2

No 14


0 200 400 600 800 10000,0

5,0x1018

1,0x1019

1,5x1019

2,0x1019

D-r

ele

as

e (

Ato

ms

/m2 s

)

Temp (C)

Dtotm2 M3M4

Present data, W on JET CFC

7.29 1021 D/m2

Previous data fine grain graphite EK98

1.87 1021 D/m2

For comparison : retention in C ( EK98, JET Dunlop CFC )

0.E+00

1.E+21

2.E+21

3.E+21

4.E+21

5.E+21

6.E+21

EK98 N11 DMS780 NB31 NB41

Deu

teri

um

ret

enti

on

[D

/m2 ] LID-QMS

NRA

A.Kreter et al

A. Kreter et al

2x 1025 D/m2

Retention on upper edge

No 15


-5,00E+017

0,00E+000

5,00E+017

1,00E+018

1,50E+018

2,00E+018

2,50E+018

3,00E+018

3,50E+018

0 200 400 600 800 1000

0

1x1019

2x1019

3x1019

4x1019

5x1019

6x1019

7x1019

D-r

ele

as

e (

Ato

ms

/m2

s)

Temp (C)

Dtot JET 1Dtot JET 2Dtot W-Droste

Comparison W bulk and W JET layer:

6-8 times more D in W JET layers

Different exposure temperatures (about 150 C)

Different waiting times until TDS

Different surface structure

No 16


No 17


Documents

No 1 V. Philipps, SEWG Fuel retention, July 2010, Garching Joint TEXTOR, MAGNUM and PISCES experiments on retention in W and mixed W/C system V. Philipps,