Properties Of 20 Cold Worked 316 Stainless Steel Irradiated At Low Dose Rate PDF Download

Recent experiments have extended the mechanical properties data base of 20 percent cold worked 316 stainless steel to a fluence of 1.3 x 1023 n/cm2 (E >0.1 MeV), the goal exposure of the Fast Flux Test Facility. Both uniaxial and biaxial tests were conducted on specimens of developmental cladding which were irradiated in the Experimental Breeder Reactor-II at temperatures ranging from 370°C to 650°C. Uniaxial tensile tests were conducted at strain rates ranging from 10-5/s to 10-3/s. Controlled Biaxial Strain Rate (CBSR) tests, recently developed at the Hanford Engineering Development Laboratory, were conducted only at a strain rate of 10-5/s. CBSR specimens are gas-loaded to produce a constant diametral strain rate. These tests are otherwise analogous to uniaxial tensile tests. The tensile strength and ductility of the cladding were generally in good agreement with the predicted values. These predictions were based on data obtained at lower fluences and at test temperatures ranging from 232°C to a maximum of 110°C above each of the irradiation temperatures. The temperature and fluence dependence of the yield strength was found to be consistent with the predictions of microstructurally-based models of irradiation effects at irradiation temperatures above approximately 500°C. The strengths obtained from CBSR testing were in good agreement with the correlations developed from uniaxial data only, although the ductility of the biaxial tests was generally somewhat lower. Both types of tests have shown that the cladding possesses the requisite strength and ductility for FFTF operation to goal exposure.