Thermal aging capsule results from Oconee Nuclear Station - Unit 1

At the Oconee Nuclear Station - Unit 1 a thermal aging capsule was removed and tested at the same time a second reactor vessel surveillance capsule was removed for testing. The thermal aging capsule had received a thermal exposure of 15,000 at 580 0F (3050C) and the irradiated capsule had received an exposure of 1.5 x 1018n/cm2. The capsule contained Charpy V-notch and tension specimens of SA-302 B modified base and weld metal and SA-533 B1 correlation monitor material. The SA-302 B base metal exhibited no significant changes in Charpy V-notch impact properties as a result of thermal aging. The heat-affected-zone data indicated a drop in upper shelf properties. This drop was attributed to limited thermal aged data points and large scatter in the base data, since the notch lateral expansion and shear fracture data did not indicate the same trend. The SA-302 B weld metal exhibited a slight increase in upper shelf energy, and the SA-533 B1 correlation material exhibited a slight decrease in upper shelf energy. No tension data are reported. The conclusions of this study agree with the results reported from the Big Rock Point reactor