Key results of commissioning activities for the emergency and scheduled cooldown system of the AES-2006 unit with the V-392M reactor plant

Abstract

The paper describes the combination of safety and normal operation functions adopted in the AES-2006 design, as illustrated by a two-channel structure of active safety systems, showing the major innovative solutions and their differences from earlier designs, such as:– The use of a pump-ejector assembly in the primary circuit emergency and scheduled cooldown and spent fuel pool cooling system;– The emergency and scheduled cooldown and spent fuel pool cooling system is designed as two fully independent channels (each channels consists of two legs, each channel leg has a capacity of 100%);– The redundancy rate is 2 × 200%.Differences in the emergency and scheduled cooldown systems are considered for the V-392M и V-320 designs. Compliance with the acceptance criteria is shown based on test results, including additional tests performed in different modes during the commissioning of the Novovoronezh NPP II Unit 1 with the V-392M reactor plant. A description and a pattern are provided for the full-scale simulator tests to justify the long-term performance of the pump-ejector assembly scheduled for 2017, including an inspection of the water-jet pump nozzle inner surface condition and the water-jet pump service life tests followed by an examination for possible damage and visible defects on the nozzle surface.As a result of the innovations, the overall reliability of safety systems has been improved. The successful completion of the life tests of the pump-ejector assembly of the emergency and planned cooling system made it possible to confirm the reliability and efficiency of the water-jet unit used for the first time in the NPP safety systems.