Microvoids Pressures of Tritium and Helium-3 in Vessel Wall with Their Accessional Effects

Abstract

Tritium and helium-3 in the steel wall of a spherical pressure vessel (SWSPV) will cause hydrogen and helium embrittlements of the wall material, respectively, and thereby change the carrying capacity of the vessel. In this paper, the formulas of tritium and helium-3 pressures within microvoids which naturally exist in SWSPV were deduced, their spatio-temporal distributions laws were analytically obtained, and by using a representative volume element (RVE) model to perform finite element simulations, the effects of gas pressures on equivalent mechanical properties of the material were studied. It is found that the higher the gas pressures are, the lower the material ultimate strength, specific elongation and percentage contraction of area are, which is in good accordance with the phenomena of hydrogen embrittlements.