Influence of Certain Metallurgical Factors on the Lifetime of Weld Joints of Metal of VVER-1000 and VVER-1200 Reactor Vessels

The influence of metallurgical factors on the radiation lifetime of metal of regular weld joints in VVER reactor vessels has been analyzed. The radiation lifetime of weld joints has been estimated by the absolute value of the critical brittleness point after operation for 60 years. The estimate for the 60 years of operation was based on the fast neutron fluence of 60 × 1022 m–2 (E > 0.5 MeV), conservative for VVER-1000 and VVER-1200 reactor vessels. The chemical composition, grade of welding wire, and type of preparation have been considered as the influencing factors.