2004 Fiscal Year Final Research Report Summary
Application of tungsten coated carbon materials for divertor
| Project/Area Number |
14580527
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear fusion studies
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| Research Institution | Kyushu University |
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Principal Investigator |
TOKUNAGA Kazutoshi Kyushu University, Research Institute for Applied Mechanics, Associate Professor, 応用力学研究所, 助教授 (40227583)
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| Project Period (FY) |
2002 – 2004
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| Keywords | Plasma-wall inyeraction / Tungsten / Carbon / High heat load / Hydrogen isotope / Helium / Divertor plate / Plasma facing materials |
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| Research Abstract |
Tungsten coated isotropic fine grained graphite and CFC have been investigated to examine interface of tungsten and carbon material, surface modification due to plasma exposure and thermal behavior of mock-ups with a cooling tube. Topics are as follows.
(a)Mechanism of carbon diffusion barrier in interface of tungsten and carbon materials.
(b)Surface modification of tungsten due to the irradiation of low energy and high flux hydrogen isotope and helium.
(c)Evaluation of thermal behavior of tungsten coated mock-ups including heat transfer to coolant by high heat load tests and FEM analyses.
Thermal behavior of micro-structure of the interface has been investigated as a function of temperature and time. These results indicate that the diffusion barrier for carbon is not expected to suppress the carbide formation at the joint interface of the tungsten coating above 1600℃. Optimization of structure and thickness will improve the performance. Surface modification and deuterium retention have been examined after the irradiation by low energy and high flux deuterium(100 eV,1×10^<22>D^+m^<-2> s^<-1>,1×10^<26>D^+m^<-2>) using a plasma simulator. Formation of blister depends on kind of tungsten, structure and irradiation temperature. These experimental results indicate that the manufacturing process of tungsten is one of the key factors for the blister formation and the retention of hydrogen isotope on tungsten. Tungsten coated CX-2002U and IG-430U have been brazed on the OFHC with a cooling tube by using Ti foil as braze material. Thermal response and thermal fatigue tests on the mock-ups have been carried out under active cooling conditions using an electron beam. In the case of W/CX-2002U/OFHC, it is demonstrated that the mock-up successfully withstood of heat load at 10 MW/m^2 at steady state. Comparison with the FEM calculation results makes clear quantitatively the thermal behavior of the mock-ups.
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