Mössbauer spectroscopy investigation of the effect of a high-dose neutron irradiation on the atomic redistribution in the industrial steel EP823

Abstract The authors studied radiation-induced structural-phase transformations that had occurred in EP823 steel of industrial application under conditions of its high-dose neutron irradiation in a fast fission reactor. The method of transmission Mossbauer spectroscopy with resonance detection and transmission electron microscopy was utilized. It has been observed that in ferritic-martensitic steel, under the neutron irradiation with doses above 50 dpa at temperatures of 570–660°C, the decomposition of a BCC solid solution together with the release of the alloying elements chromium, molybdenum, and carbon from the metal matrix occurs. It is accompanied by the formation of an intermetallic χ phase and carbides of the Me23C6 type. The authors revealed the formation of the vacancy-clustered and supposedly gas-filled pores in the structure after irradiation.