LAUSR

Abstract The embrittlement of reactor pressure vessel (RPV) steel owing to fast- neutron irradiation damage is one of its primary failure mechanisms. In this work, neutron irradiation experiments were performed on a commercial RPV steel at a high temperature (292 °C) using a neutron irradiation experimental reactor. Then the elastic modulus measurements and XRD analysis were performed on the RPV steel before and after irradiation in a hot laboratory. The results shows that the Young modulus and shear modulus of RPV steel do not change during neutron irradiation, the half-width of peak shape parameters and lattice constant of XRD diffraction peak remain unchanged, and no new phase is formed in RPV steel during irradiation embrittlement, the crystal structure of RPV steel does not change after neutron irradiation damage. It is found that the elastic modulus of the macro-mechanical properties and the micro-structure characterized by XRD analysis are consistent with each other during the neutron irradiation embrittlement process of RPV steel. Finally, this paper points out that the conclusion of neutron irradiation damage has no effect on the elastic modulus of RPV steel is of great significance to the structural integrity analysis and safety evaluation of RPV in the whole life of nuclear power plant.