氚在RAFM钢表面的吸附研究

Tritium Adsorption Property on RAFM Steel Surface

采用气相吸附法研究了室温下RAFM钢表面对氚的吸附与释放行为,并使用316L钢、1Cr18Ni9Ti钢进行了对照实验。结果表明,RAFM钢表面的氚吸附与释放性质与316L钢、1Cr18Ni9Ti钢的非常相似,相同表面状态的样品,在相同实验条件下的吸附氚量相差不超过50%。可推测,未经深度除水处理的RAFM钢暴露于氚后,表面会形成富氚层,浓度远高于基体溶解氚,厚度不大于10μm。表面氚的形态以化学吸附和物理吸附的氚化水为主,约占90%以上。室温下RAFM钢表面吸附的氚在干燥气氛中的释放非常缓慢,但遇水会因氚-水间的同位素交换而加速释放。

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 10μm.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.