Experimental Tests of Irradiation-Anneal-Reirradiation Effects on Mechanical Properties of RPV Plate and Weld Materials
SourceThe Charpy-V (Cv) notch ductility and tensile properties of three reactor pressure vessel (RPV) steel materials were determined for the 288°C (550°F) irradiated (I), 288°C (550°F) irradiated + 454°C (850°F) -168 h postirradiation annealed (IA), and 288°C (550°F) reirradiated (IAR) conditions. Total fluences of the I condition and the IAR condition were, respectively, 3.33 × 1019 n/cm2 and 4.18 × 1019 n/cm2, E > 1 MeV. The irradiation portion of the IAR condition represents an incremental fluence increase of 1.05 × 1019 n/cm2, E > 1 MeV, over the I-condition fluence. The annealing treatment produced full Cv upper shelf recovery and full or nearly full recovery in the Cv 41 J (30 ft-lb) transition temperature. The Cv transition temperature increases produced by the reirradiation exposure were 22% to 43% of the increase produced by the first cycle irradiation exposure. A somewhat greater radiation embrittlement sensitivity and a somewhat greater reirradiation embrittlement sensitivity were exhibited by the low nickel content plate than the high nickel content plate. The IAR-condition properties of the surface vs. interior regions of the low nickel content plate are also compared.