Effect of chemical composition of reactor WWER-1000 vessel materials on dose parameters of their radiation embrittlement

The paper gives results of an experimental investigation into the effects of alloying (approx 0.2...3.0% Ni, approx 0.5...3.0% Mn) and impurity (approx 0.004...0.035% P, approx 0.05...0.35% Cu) elements on susceptibility to irradiation embrittlement of low-alloy vessel materials under high-intensity irradiation conditions used research and commercial reactors as well as generalizes data on the irradiation embrittlement of materials used in WWER-1000 vessels (the base metal of 15X2HMFA-A steel and its weld metal). Special attention is paid to irradiation embrittlement enhancement in the weld materials containing more then 1.5% Ni. Relying on the analysis of experimental observations on the change in commercial metal properties (including an achieve metal of WWERs - 1000 now in operation) under neutron irradiation,it was concluded that the relationship describing the dose dependence of irradiation embrittlement of the weld metal taking into consideration its increased Ni contents is to be corrected