Irradiation creep simulation at low proton flux

Light-ion irradiation creep simulation was carried out for 316 stainless steel at low proton flux (proportional2.5 . 10-8 dpa/s) and with low fluence (<2 . 10-3 dpa) in an attempt to prevent a serious microstructural modification. Both 20% cold worked (CW) and recrystallized and ages (RCA) specimens were examined. A linear stress dependence (41-124 MPa) and a weak temperature dependence (200-3500C) were observed for both specimens in the torsional in-situ creep measurements. The creep rate was only slightly lower in the RCA specimen. A transient with a ''negative'' irradiation creep was observed only in the RCA specimen as previously reported at higher flux. The SIPA climb mechanism fails to predict the high creep rates of the present study as well as those of the primary in-reactor creep. The CCG model of Henager and Simonen for low fluence appears to be more promising, though it still does not provide a complete explanation. (orig.)