Simulated transient behavior of HT9 cladding

Simulated transient tests were performed on sections of HT9 fast-reactor fuel pin cladding irradiated to a fast fluence of nearly 16 x 1022n/cm2 at temperatures ranging from 370 to 620 degrees C. After the fuel was removed, these specimens were internally pressurized and heated at one of several constant rates (0.56, 5.6, or 110 degrees C/s) until specimen failure occurred. A slight reduction of strength was observed in irradiated cladding, particularly at 110 degrees C/s, when compared with transient results from unirradiated HT9 control specimens; however, this strength reduction did not correlate with either fluence or irradiation temperature. A small reduction of ductility was also observed for irradiated cladding failing at temperatures above 800 degrees C at the lower heating rates (0.56 or 5.6 degrees C/s); irradiated cladding was generally more ductile at 110 degrees C/s than unirradiated HT9 cladding. The HT9 cladding results are compared with similar transient data obtained previously from 20% cold-worked type 316 stainless steel (316 SS) cladding