Procedure of accelerated irradiation results usage for prediction of the material state corresponding to long-term operation of the reactor pressure vessel

摘要

The analysis of available data on radiation embrittlement of WER-1000 RPV materials obtained in non-accelerated (according to surveillance specimens programs) and accelerated irradiation conditions has been carried out. With model assumption that the transition temperature shift can be presented as a sum of radiation part ΔT_F and thermal part ΔT_t in ΔT_k = ΔT_t +ΔT_F, a procedure of accelerated irradiation results application for prediction of change of properties of WER-1000 reactor pressure vessel weld materials corresponding to long-term operation was suggested. This procedure is described by the formula ΔT_k =ΔT_t+ ΔT_F~(acc) + ΔT_(Flux), where ΔT_T - transition temperature shift due to thermal ageing determined for the period of time ＞ 100 000 hours according to existing dependencies or on surveillance specimens, ΔT_F~(acc) - transition temperature shift after accelerated irradiation. ΔT_(Flux) = 0,25ΔT_F~(acc) -addition to flux effect for weld material with nickel content more than 1.5%. For RPVs being under operation more than 30 years it is proposed to obtain predictive values of the vessel materials radiation embrittlement with the use of accelerated irradiation of surveillance specimens of temperature sets with exposure time ＞ 100000 hours. The work was carried out within the framework of the Federal Agency lot on science and innovations, State Contract 02.523.12.3012 and financial support of ISTC fund (Project № 3420).