Irradiation Hardening of Pressure Vessel Steels at 60°C: The Role of Thermal Neutrons and Boron

摘要: Six split melt A533B-type model alloys, with different combinations of copper, nickel and boron contents, were irradiated at 60 C in a neutron spectrum thermal-to-fast (E > 1 MeV) ratio about 370. The resulting yield stress increases compared to hardening produced by irradiations low flux ratio. latter data obtained larger experiment on that showed: (i) negligible effect flux; (ii) the square root fluence above threshold; (iii) an individually weak, but collectively significant, influence nickel, manganese, phosphorus molybdenum. These other observations have been interpreted suggest temperature is caused features formed displacement cascades. However, this interpretation not consistent results study which show are even for conditions dominated energy PKAs created thermal neutrons. dpa efficiency factor was estimated be 1.7 {+-} 0.5, comparable corresponding theoretical residual defects. also transmutant products from {sup 10}B(n,{alpha}) reaction may contribute small increment hardening.