Irradiation creep of 20% cold worked 316 stainless steel under low proton flux

Creep deformation under a low flux of 16 MeV protons (proportional2.5 . 10-8 dpa/s) was examined for 20% cold worked 316 stainless steel at 200-3500C, 41-124 MPa using a torsional creep apparatus. Weak temperature dependence and linear stress dependence of irradiation creep rate were observed. Irradiation creep compliance was about one order higher than in the high flux (proportional 1 . 10 -6 dpa/s) case. Calculation of steady state interstitial concentration suggests that recombination is the dominant mode of defect loss at about 3000C and below. The compliance difference between the high and the low flux light-ion irradiation creep can be explained by the recombination. The SIPA mechanism predicts a creep rate comparable to the steady state in-reactor creep rate but much lower than the primary in-reactor and the light-ion irradiation creep rate even if microstructure relaxation and defect recombination are considered. (orig.)