Core materials studies improve fast breeder performance

Structural materials in a breeder reactor core tend to exhibit three important phenomena, swelling, irradiation creep and irradiation hardening. The mechanics and consequences of those effects on reactor fuels and other components are discussed. In an effort to improve the reliable performance of replaceable core components in fast breeder reactors, the United States and other countries involved in breeder reactor development are engaged in a programme aimed at a better understanding of the behaviour of reactor core materials. This work, which is described, is intended to lead to extended component lifetimes, reduced fuel cycle costs and improved breeding characteristics. (U.K.)