Probability analysis of the safety of the second energy module of the leningrad nuclear power plant

A special international program was undertaken to estimate the safety of the second power unit at the Leningrad Nuclear Power Plant after reconstruction and the effectiveness of the new safety measures introduced. The analysis is based on the IAEA method, modified for RBMK reactors. The calculations employ a full-scale model of the risk of the power unit and the initial data for a 10-year operating period. After reconstruction, the frequency of serious accidents with core damage is 1.4.10 super(-5) per reactor-year and is acceptable in terms of the OPB-88/97 requirements. The influence of reconstruction is considerable: according to the estimates, the risk is reduced by a factor of more than 100. The results of the analysis permit suggestions regarding further increase in safety and reduction in cost of the reconstruction without increasing the risk of accident.