Radiation Effects on the Long-term Ageing of Spent Fuel Storage Containers

Abstract

The properties of a long-term interim storage low-carbon steel container could be changed by radiation-induced damage. In this paper, the gamma and neutron flux in the container are estimated over 300 years for pressurised water reactor spent fuels. Gamma radiation is the main contributor to the damage flux during the whole storage period (from 3 × 10⁻⁸ dpa y⁻¹ after 2 years of storage to 4 ×10⁻¹¹ dpa y⁻¹ after 300 years, where dpa is displacements peratom). A cluster dynamics model is used to calculate the point defect concentrations and their effect on the copper precipitation kinetic and point defect clustering for different storage conditions. The shear stress increases in the first years of storage, from 23 to 50 MPa for a Cu content varying from 0.05 to 0.25%. The temperature or the damage rate has an effect on the kinetic only at the beginning of the storage. The hardening is entirely caused by copper precipitation enhanced by vacancy supersaturation.