HT-7 ASIPP

Surface Analysis of CLAM steel,EUROFER97 steel and W Irradiate

d in HT-7 Tokamak

Qiang Li1,2 Qunying Huang1 Jinnan Yu3 Jiangang Li1 Yican Wu1 Xiaoxiong He1,2

1 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031, CHINA

2 Hefei University of Science and Technology, Hefei, Anhui, 230039, CHINA

3 China Institute of Atomic Energy, Beijing 102413, CHINA

HT-7 ASIPP

OUTLINEAbout CLAM steel,EUROFER97 steel and WExperiment procedure Sample Irradiation experiment Surface analysisResult and discussion Surface morphology Surface compositionconclusion

HT-7 ASIPP

About CLAM steel,EUROFER97 steel and W

CLAM steel and EUROFER97 steel • low activation ferritic/martensitic steel• Good properties for thermal and neutron irradiation

• Being considered as structural material and the first wall material in tokamak

HT-7 ASIPP

About CLAM steel,EUROFER97 steel and W

W• Refractory high-Z material• High melting ponit,low vapor pressure,good ther

mal conductivity,high temperture strength and sputtering resistance

• Being considered as plasma facing components

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Experiment procedure

Sample• Composition of CLAM steel, EUROFER97 steel( wt ％ )

pure multicrystal tungsten(~99.99% wt)• Size:15*7*1.5 mm • All samples were polished and cleaned with acetone and abs

olute alcohol,and then were dried by hot air.

Fe Cr Mn W Si V C Ta Ni

CLAM Bal 8.85 0.42 1.50 0.01 0.20 0.084 0.072 0.02

EU97 Bal 8.82 0.37 1.10 0.005 0.19 0.10 0.068 0.021

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Experiment procedure

Irradiation experiment• HT-7 tokamak

medium size with limiter, and R=1.22m, a=0.285m, BT≤2.2T

the first wall material is 1Cr18Ni9Ti stainless steel, and the limiter material is graphite coated with SiC

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Experiment procedure

• Sample shelf and its position in HT-7

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Experiment procedure

• Plasma average parameters during experiment center: boundary: Ip =125kA ne =1.5*1019m-3

Te =700eV Ti =450eV

All samples were irradiated by 802 shots ， total irradiation time is about 1200 seconds

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Experiment procedure

Surface analysis• Scanning Electron Microscope (SEM)• X-ray Photoelectron Spectroscopy (XPS)

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Result and discussion

Surface morphology• CLAM

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Result and discussion

• EUROFER97

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Result and discussion

• W

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Result and discussion

• Number and diameter of blisters

it seemly equal for blister number in CLAM steel surface and EUROFER97 steel surface, and most of blister diameter is less than 1μm

the blisters in W surface are very little ,their diameter are more than 1μm

1

10

100

1000

10000

<0. 2μ m 0. 2- 0. 5μ m 0. 5- 1μ m >1μ m

Bl i ster di ameter

Numb

er o

f bl

iste

r

CLAMEUROFER97W

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Result and discussion

• SummaryThe surface blisters of CLAM steel and EUROFER97 st

eel are very denseThe blisters seemly range along line in the suface of two

kinds of steelsBlisters are observed in the surface of WBlisters are not observed in the surface of all samples w

hich are far to center plasma

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Result and discussion

Surface composition• Si Si peaks are obvious in No.2

samples surface, but it is not obvious for No.1 samples

• Other elements

No obvious change for No.1 samples and No.2 samples

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conclusion

Relative to W,CLAM steel and EUROFER97 steel are more easy to blister when irradiated by plasma

low activation ferritic steel can be used as fisrt wall materials when considering its plasma irradiation resistance ability

If select W as the plasma facing materials,such as divertor armor, more deep researchs must be proceeded