Abstract
The He production rate(i.e.,He/dpa)in nuclear reactors strongly affects the degradation of material prop-erties.This is an important but not yet fully understood issue.Here,the effect of He/dpa on bubble char-acteristics in Fe9Cr1.5W0.4Si ferrite-martensitic(F/M)steel was in situ studied during 400 keV Fe+and 30 keV He+dual-beam irradiation at 723 K with three ratios of 100,500,and 2500 appm He/dpa and subsequent stepwise annealing using transmission electron microscopy(TEM).He/dpa strongly affected the bubble characteristics.During irradiation,the higher the He/dpa,the smaller the size of irradiated bubbles,but the higher their density.However,He/dpa didn't affect the final saturation size of irradiated bubbles for all three cases,which was～2.2 nm.During annealing,high He/dpa caused large,immobile,dense polyhedral bubbles with a wider bubble size distribution,while low He/dpa caused small,low-mobility,and relatively low-density spherical bubbles.It was found that the higher the He/dpa ratio,the greater the swelling during irradiation and annealing,and annealing further enhanced the swelling.Moreover,the tunnel structure was first found in body-centered cubic(BCC)F/M steel during in-situ irra-diation.The current work provides valuable and potential insights for further understanding the He/dpa effects in materials serving in different nuclear reactors.
基金项目
National Natural Science Foundation of China(U1967211)
National Science Fund for Distinguished Young Scholars of China(12225506)
NETL
NSTL
万方数据