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The paper considers the generalized temperature dependence of the stress intensity factor KJC in the WWER-1000 reactor pressure vessel metal, which was derived based on the surveillance test data for fracture toughness. The consistency of the shape of the Master curve and 95 % upper and lower confidence bounds with the experimental dependence of crack resistance parameters on temperature was studied. From the point of view of the level of conservatism and acceptability, a comparison of the normative curves of fracture toughness according to NPRR (Nuclear Power Rules and Regulations) G-7-002-86 and SOU NNEGC (Standard of organization of Ukraine, National Nuclear Energy Generating Company) 177:2019 with a 5 % confidence bound of the Master curve was carried out. The possibility of using RT0 temperature as a temperature index instead of TK for the normative fracture toughness curve of SOU NNEGC 177:2019 was considered [ABSTRACT FROM AUTHOR]

The comparison of experimental values of the critical brittle temperature ΔTF and reference temperature ΔT0 of VVER-1000 reactor vessel weld metal with an elevated content of manganese and nickel is performed. ΔTF and ΔT0 values are defined proceeding from the standard impact bend Charpy and Charpy cracked fracture toughness specimen tests, respectively. Specimens were irradiated in industrial reactors in the frame of surveillance specimen program up to the fast (E ≥ 0.5 MeV) neutron fluences corresponding to the NPP long term operation period. The research results showed the shifts ΔTF and ΔT0 to agree with each other. Besides, it was discovered that in the range of over-design fluences the design embrittlement model has a tendency to underestimate the critical brittle temperature shift. [ABSTRACT FROM AUTHOR]

The paper presents the statistical analysis of experimental results of radiation-induced critical brittle temperature ΔTF shifts and reference temperatures ΔT0 obtained respectively from the impact bend and fracture toughness tests of the reactor vessel metal surveillance specimens to define the possibility of their mutual application for the irradiation embrittlement coefficient to be determined more accurately. The correlation between these parameters is shown to remain up to the accumulation of over-design fast neutron fluence. [ABSTRACT FROM AUTHOR]

The paper presents the procedure developed at the Department of Radiation Material Science of INR NAS of Ukraine for longitudinal radiometric scanning of surveillance specimens of the Ukrainian reactor vessels and its joint application with macrostructural analysis for sorting specimens relative to their location in VVER-1000 reactor under the irradiation. The specific examples of specimen sorting using both procedures are given. [ABSTRACT FROM AUTHOR]

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