Tritium Adsorption Property on RAFM Steel Surface

The adsorption and release behavior of tritium on the RAFM steel surface at room temperature was studied by the gas phase exposure method. The results show that the adsorption and release properties of tritium on RAFM steel are similar to those of 316L and 1Cr18Ni9Ti steels. The differences of adsorption capacity of the samples are less than 50% under the same surface state and the same experimental conditions, and the exchange properties between the adsorbed water and gaseous tritium are similar. It can be inferred that when the RAFM steels are exposed to tritium at room temperature, tritium-rich layer will form on the surface and the tritium concentration in this layer is far more than that in matrix, and the thickness is not more than 10 μm. The main form of tritium adsorbed on the surface is chemcally and physically adsorbed tritiated water, accouting for more than 90%. The release of tritium on the RAFM steel surface in dry atmosphere is very slow at room temperature, but the isotope exchange between surface water and liquid water or vapour will accelerate the release rate.