Effects of Neutron Flux and Irradiation Temperature on Irradiation Embrittlement of A533B Steels

Abstract

Irradiation embrittlement of A533B steels with low copper contents were investigated from the point of dose rate and irradiation temperature effects. Change of neutron flux in the range from -1012 to -1013 n/cm2/s (E> 1MeV) did not have a significant effect on the embrittlement. Irradiation temperature change of 1°C resulted in the transition temperature shift (ΔT41J) of about 1°C and yield stress change (Δoy) of about 0.8MPa. Factors that might affect the embrittlement of low copper steels are also discussed.

Current understanding of radiation-induced degradation in light water reactor structural materials

“…This expression was derived from data of C-Mn steels in gas-cooled reactors over a wide temperature range [27]. Similar linear irradiation temperature dependence was also observed in weld metals and A533B steels irradiated in MTRs [25,28]. Temperature dependence was clearer for higher Cu content, while it seemed to be relatively small at temperatures lower than 300 • C for high-Cu steels.…”

“…It was reported that a coarse grain HAZ showed a higher transition temperature shift after MTR irradiation than others such as a fine grain HAZ [23]. The size distribution of fine precipitates such as Mo 2 C and AlN was found to affect transition temperature shift in low-Cu A533B steels after MTR irradiation [25]. The transition temperature shift was smaller for steels containing finer and denser carbides [25].…”

“…The size distribution of fine precipitates such as Mo 2 C and AlN was found to affect transition temperature shift in low-Cu A533B steels after MTR irradiation [25]. The transition temperature shift was smaller for steels containing finer and denser carbides [25]. The influence of the fine carbide distribution might be related to a recent observation under heavy ion irradiation that radiation hardening was larger in near-carbide regions compared to matrix regions without carbides [26].…”