A multi-purpose high-temperature gas-cooled reactor, excluding a power generation, is being designed to be operated as a heat source of the reducing gas which is applied to a direct steel-making process.
The protection of hydrogen permeation through the heat exchanger tubes of the high-temperature gas-cooled reactor into a primary coolant is one of the most severe problems. Also in a thermonuclear fusion reactor the protection of tritium diffusion is considered to be essential from the standpoint of environmental contamination, because tritium has radioactivity.
In the 1st report, a “liquid-metal-inbetween” method-hydrogen permeation is reduced by degassing through a palladium foil which is installed in a liquid metal region inbetween two metallic walls -is proposed, and the experiment verified the possibility of this idea. Moreover, it is shown that the reducing rate of hydrogen permeation can be lowered to any amount, if the area of palladium foil is large enough.
In addition, the necessary development or technological problems when applied to an actual heat exchanger are also described.