Conducting Assessments for Fast Fracture of Nuclear Reactor Metal

Nuclear power plants must be safe, reliable and ensure the planned supply of electricity. The metal of the equipment operates in conditions of high pressure values and fluid tem-peratures, in radiation and in corrosive working environments. These factors cause deg-radation of the metal mechanical properties. Defects appear in the structure and this leads to a decrease in the operability of the equipment and to compromise the NPP safety. In the "worst case", the facilities could be torn apart and a nuclear accident could occur. The mechanical characteristics of the metal should be periodically examined. The topic in this article is the study of stress intensity factor for defects on the inner surface of the reactor vessel. The metals on the inner surfaces of the vessels of two nuclear reactors were studied by a visual method. Stress intensity coefficients have been calculated at the site of defects, taking into account the influence of the embrittlement factors. The results are compared with the requirements of the strength standards. The purpose of the investigation is to check whether the facility can continue to be operated safely. The algorithm can be used as a methodology for periodically examining defects detected during the operation of the unit.