Repeatability of Irradiation Damage and of Recovery by Post-Irradiation Annealing of EUROFER Base Steels

Former investigations clearly revealed that embrittlement and hardening of reduced-activation ferritic-martensitic (RAFM) steels after neutron irradiation can be reduced remarkably by post-irradiation annealing (PIA). This study demonstrates the repeatability of damage and recovery mechanisms for EUROFER-based and EUROFER-ODS-HIP-steels by using specimens of previous 330 degrees C Bor 60 reactor (SSC RIAR) irradiations. Specimens were investigated in the irradiated state after a first PIA, after a subsequent further irradiation, and after a second annealing. Both tensile and Charpy-V impact tests clearly indicate that embrittlement occurs after the second irradiation of intermediately annealed (and, thus, recovered) material in the same order as after the first irradiation. In addition, a subsequent PIA leads to a complete recovery of the newly applied neutron damage, suggesting that lifetime of neutron-exposed fusion power plant components could be extended substantially by means of intermediate annealing. (C) 2017 Published by Elsevier B.V.