Vacuum vessel for thermonuclear device

As a material constitution of a vacuum vessel for a thermonuclear device and a method of sharing the function thereof, a titanium/titanium alloy is used as an electric resistor and a structure reinforcing material. Further, as a vacuum boundary material for containing hydrogen/hydrogen isotopes, an aluminum/aluminum alloy or a similar material which is less activated and has no problem regarding compatibility with hydrogen is used. Further, in order to set a vacuum boundary for containing hydrogen/hydrogen isotopes, a surface treatment is applied on the inner surface of a titanium/titanium alloy vessel. When titanium is used corresponding to the electric resistance value required for the vacuum vessel, the plate thickness thereof can be set to 20 times as that of aluminum, in addition, the strength of the material is high. Further, a radiation dose rate in the vacuum vessel can be lowered by disposing an aluminum alloy on the inner side of the titanium alloy. Then, the performance of electric resistance, mechanical strength, establishment as a hydrogen isotope containing vessel are satisfied simultaneously with less activation. (N.H.)