低誘導放射化フェライト鋼F82Hのガス放出特性

概要

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Outgassing characteristics of F82H ferritic steel as a low activation material for the blanket of fusion device were investigated. A test chamber was constructed by welding F82H ferritic steel plates. The inner surface of the chamber was buffed and electropolished. The test chamber was degassed by the prebaking at temperature of 350℃ for 20 h in vacuum. Then outgassing rates of the test chamber were measured by the throughput method as a function of pumping time for the cases that the test chamber was baked and not baked. The typical outgassing rate after baking at 250℃ for 24 h was 3 x 10^-9 Pa・ms^-1 and it seems that this value is sufficiently small to produce pressures at least as low as 10^-9 Pa in the vacuum chamber made of F82H ferritic steel. In the pump-down of the test chamber without baking after exposure to air, the outgassing rate decreases with pumping time and reached 1 x 10^-7 Pa・ms^-1 at t = 10^5 s. The activation energy of hydrogen in bulk diffusion in the F82H ferritic steel was measured and found to be 7 kcal/ mol.
社団法人プラズマ・核融合学会の論文
1997-09-25