MICROSTRUCTURAL EVOLUTION IN NEUTRON-IRRADIATED STAINLESS STEELS: COMPARISON OF LWR AND FAST-REACTOR IRRADIATIONS

Abstract

A series of Bor-60 fast-reactor irradiations have been completed on commercial and laboratory heats of 304SS and 316SS irradiated at 330°C to doses from 5 to 20 dpa. A quantitative comparison has been made to assess critical changes in material microstructure due to differences in fast-reactor versus lightwater-reactor irradiation environments. Direct comparisons are also made between cold-worked 316SS baffle-bolt materials irradiated in Bor-60 to similar cold-worked 316SS heats removed from the PWR service after moderate to high irradiation exposures. The evolution of Frank loops, precipitates and cavities will be documented and evaluated with respect to differences in irradiated spectrum, dose rate and temperature.