Plasma facing components of nuclear fusion reactors employing tungsten materials
AssigneesJapan Atomic Energy Research Institute, Tokyo Tungsten Co., Ltd.
InventorsMasato Akiba, Kazuyuki Nakamura, Akira Ichida, Takehiko Hayashi
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Abstract
In a plasma facing member exposed to a plasma beam of nuclear fusion reactors or the like, such as an electron beam, a tungsten layer is formed by the use of a CVD method and has a thickness of 500 micron meters or more. The tungsten layer may be overlaid on a substrate of molybdenum or tungsten and comprises included gases reduced to 2 ppm or less and impurities reduced to 2 ppm or less. The tungsten layer is specified by either a fine equi-axed grain structure or a columnar grain structure. Alternatively, the material of the substrate may be, for example, Cu alloy, stainless steel, Nb alloy, or V alloy.
Claims4
A method of forming a plasma facing surface on a substrate formed of a predetermined material by chemical vapor deposition in a reaction chamber, said method comprising:
- uniformly depositing on the substrate a tungsten layer a deposition rate of 200 μm hour to a thickness of 2.5 mm by heating the substrate to a predetermined temperature, rotating the substrate at a predetermined speed, supplying a hydrogen gas and a WF6 gas into the reaction chamber to form a mixture of the hydrogen gas and the WF6 gas having a ratio of the WF6 gas to the hydrogen gas of 1:5 to maintain a pressure of the reaction chamber at 1.3 kPa, and causing the mixed hydrogen and WF6 gas to flow at a predetermined flow rate.
Dependencies are inferred from the claim text.