The changes of the structural, magnetic, and mechanical properties in a reactor pressure vessel steel neutron-irradiated at 70°C

The irradiation embrittlement of reactor-pressure-vessel. steel has been one of the main safety concerns in nuclear power plants. In the present study, an SA508-3 RPV steel was irradiated by neutrons with various fluences up to 10(18) n/cm(2) (E greater than or equal to 1 MeV) at a temperature of approximately 70 degrees C. The irradiation responses of the structural, the magnetic, and the mechanical properties of the steel were investigated by means of X-ray diffraction, Mossbauer spectoscopy, magnetic Barkhausen noise, and micro-Vickers hardness measurements. The transitions of all of these parameters occurred above a neutron dose of 10(16) n/cm(2). The results of the X-ray and the Mossbauer experiments revealed that neutron irradiation led to the possibility of partial amorphization in the investigated RPV steel. The changes of the physical and the mechanical properties were discussed in terms of irradiation-induced cascade damage of crystalline materials.