Study of the metal of the irradiated weld of the WWER-440 reactor body after 45 years of operation

This work presents the results of a study of the mechanical characteristics and chemical composition of metal samples cut from a non-irradiated weld seam of a WWER-440 reactor vessel after 45 years of operation. The calculated distribution of the critical temperature of brittleness over the thickness of the irradiated weld seam of the WWER-440 reactor vessel (140 mm) is obtained taking into account the distribution of the initial properties, the content of phosphorus and copper, and the density of the fast neutron flux over the thickness of the seam. Since all the circumferential welds connecting the shells in the WWER-440 reactor vessel are manufactured using the same technology, the results of the study of the non-irradiated weld can be used to assess the distribution of properties in the irradiated weld. At the same time, it is assumed that the effect of thermal aging at a temperature of 270°C (operating temperature of a non-irradiated weld) is small and can be neglected.