Tritium trapping capacity on metal surface

Abstract

It is well known by experience that tritium is apt to stick to the surface of various materials. If the amount of tritium trapped to the surface is not small enough compared to the amount of tritium introduced to the system, interactions of tritium with the system materials affect the behavior of tritium in a manner peculiar to the system. This phenomenon has been named as the system effect of tritium by the present authors and the way to quantify this effect using the serial reactors model, connection of perfect mixed type reactors and plug flow type reactors, also has been proposed. The tritium trapping capacity on the surface of stainless steel, copper or aluminum is quantified in this study considering that the surface water consists of physically adsorbed water, chemically adsorbed water and structural water. It is observed in this study that the amount of surface water on each material in this study gives non-negligible tritium trapping capacity and that the structural water controls the tritium trapping capacity when the vapor pressure is low or when temperature is high. Further phenomenal discussion from the viewpoint of material science is required because the interaction of tritium with material surface is observed to be highly dependent on the surface condition.