Full-Scope Probabilistic Safety Assessment of Balakovo Unit 1 in Russia

The Balakovo Nuclear Power Plant operating in Russia has four operating units of a VVER-1000 type. The first unit was connected to the grid on Dec. 28, 1985, and put in commercial operation on May 23, 1986. According to modern requirements of the Russian Nuclear Regulatory Authority, the full-scope probabilistic safety assessment (PSA) must be performed to extend the license for operation beyond an initial 30-year lifetime of the unit. The paper presents the results of the Level 1 PSA covering internal initiating events for power and shutdown operational plant states, internal hazards (fires and floods), and external hazards, including natural and man-made events, in particular, seismic impact, and aircraft crash.