Objective
The Beneficiary, Rosenergoatom, and the End-User, Balakovo Nuclear Power Plant, intend to enhance the nuclear safety of the units 1, 2 and 3 of Balakovo NPP, more specifically under emergency conditions, by improving the protection of the primary circuits against overpressure.
At each unit of the Balakovo NPP, the existing pressure relief system of the pressurizer is equipped with 3 (three) main relief valves manufactured by Sempell (VS99 Type). Each main valve is actuated by 2 (two) medium-operated pilot valves; only one of these 3 main valves, the so-called control valve, is additionally equipped with a remote-controlled Solenoid Valve and motor-operated angle stop valve connected to a separate pressure relief line.
This system for the protection of the pressurizer against overpressure was designed some 20 years ago; thus it does no more fulfil recent requirements on reactor protection. In view of this situation, the purpose of the present project is to remedy the lack of redundancy and diverse safety.
Result
The upgrading of the pressurizer safety valves on all three Units has been compleeted by replaceing existing pressurizer safety valves for the new ones. The commissioning tests were performed. The Certificates of the Provisional and Final Acceptance are signed. The Final Technical Report was completed on 26.02.2008