某1000 MW压水堆核电站循环水系统冬季运行方式优化研究

Optimization Study on Winter Operating Procedures of Circulating Water System of a 1000 MW PWR Nuclear Power Plant

某1000 MW压水堆核电站机组循环水系统为海水直流式供水系统,该系统采用一机三泵母管制布置方式为常规岛凝汽器及其辅助冷却系统提供冷却水,循环泵为定速泵,冬季两台循环泵运行,夏季三台循环泵运行。当前循环水系统冬季运行方式存在如下问题:两台泵运行状态下瞬发停泵二切一后,会连锁打开虹吸破坏阀,导致启动备用泵前还要关虹吸阀抽真空,耗时较久(0.5 h及以上);冬季通常是将中泵作为备用,而备用边泵是否可行以及有无凝汽器水室超压或循环泵超载风险,需要分析论证。通过Flowmaster进行建模计算,分析了冬季瞬发停泵二切一启动备用泵、不开启虹吸破坏阀的可行性,论证了备用边泵是否会引起凝汽器水室超压或循环泵超载,以期为循环水系统运行方式优化提供理论支撑。

The circulating water system of the 1000 MW pressurized water reactor nuclear power station unit entailed in this work is a once-through seawater supply system,which adopts the scheme of"one turbine,three pumps"to the cooling water supply for the condenser and its auxiliary cooling system of the conventional island.The circulating pumps employed in the system are constant speed pumps,of which two operate in winter and three operate in summer.However,there exist the following problems in the current winter operating procedures of circulating water system:when one of the two serving pumps is stopped,the siphon breaker valve will be opened consequently,which requires an additional step of turning off the siphon breaker and vacuumizing prior to waking up the standby pump,causing unnecessary time consumption(0.5 h or more).In the conventional winter operating mode,the middle pump is usually shut down as standby.And it is worthy of study the feasibility of using side pump as standby,and the risk of overpressure in the condenser water chamber or overload of the circulating pump.Through Flowmaster modeling and calculation,this paper analyzes the feasibility of stopping the pump immediately in winter and starting the standby pump without opening the siphon breaker valve,and demonstrates whether assigning the side pump as standby will cause overpressure of the condenser water chamber or overload of the circulating pump.The analysis of this work is expected to provide theoretical support for optimizing the operating procedures of the circulating water system.