Experience of commissioning the AES-2006 design (V-392M reactor plant) steam generator blowdown system
Structural features of the AES-2006 design (V-392M reactor plant) steam generator blowdown and drainage system have been considered. The structural features of components and the system as the whole have been comprehensively analyzed, and the advantages and deficiencies of the circuitry and design solutions used have been shown. An apparent advantage of the system's flowchart is an increase in the maximum blowdown rate to 140 t/h. At the same time, problems have been revealed caused by insufficient elaboration of the structure elements. Based on the earlier experience of the system commissioning, a modified flowchart has been proposed for the steam generator blowdown and drainage using multi-way valves with a MEO drive (an electric single-turn actuator) as part of the system. The flowchart modification makes it possible to reduce the specific amount of metals in the system and to have an extra free space for the maintenance of the system's regenerative heat exchanger in a pressurized shell; to use eight multi-way valves for the steam generators instead of 36 electromagnetic valves; and to reduce the operation and repair cost. Modifications have been proposed to the regenerative heat exchanger design to give it a greater efficiency, including installation of circular partitions in the lower inlet (pressure) and the upper outlet chambers. As the result, the regenerative heat exchanger becomes a three-way heat exchanger on the tube side, leading to the required flow rate increase. The above improvements will make it possible to improve the efficiency and reliability of the steam generator blowdown and drainage system for the performance of its design functions which will lead to the secondary circuit's water chemistry to be arranged so that to minimize the quantity of deposition on the heat-exchange surface of the PGV-1000MKP steam generators.