蒸汽发生器主给水管道不同位置断裂后设备冷却水系统泵厂房漫流特性分析

Analysis of the Overflow Characteristics in the Component Cooling Water System Pump Building when the Steam Generator Main Water Supply Pipe Broken at Different Positions

核电厂蒸汽发生器主给水管道横跨设备冷却水系统(CCS)泵厂房,其中布置有柴油机、泵等重要设备。在CCS泵厂房发生蒸汽发生器主给水管道双端破裂事故工况下,需保证布置在CCS泵厂房内的CCS泵组不会因为水淹而造成失效,因此,需要对该漫流特性进行评价分析。已有研究大多关注管道破裂后流体高速喷射行为,而较少研究喷射流体在CCS泵厂房中漫流积淀情况,同时由于设备冷却水系统泵厂房空间尺寸巨大、结构复杂,很难开展原型尺寸实验研究。因此分别对破管位置位于CCS泵厂房5.334 m层空间和CCS泵厂房11墙与近核岛侧防甩墙之间的压力隔间两类事故场景分别进行三维数值计算。模拟结果表明:在蒸汽发生器双端断裂触发跳泵事故下,泄放水流量在11 s内即迅速下降,破口位置处于5.334 m层空间和压力隔间两类条件下均不会淹没CCS泵防水台,不影响CCS泵的正常运行。破口位于5.334 m层空间位置时设计预留开孔能有效排出漫流的泄放水;破口位于压力隔间内时设计的钢格栅也能有效排出漫流的泄放水。本研究为CCS泵厂房空间设备冷却水系统泵厂房防水淹策略优化设计提供重要数值参考。

The main feed water pipeline of the steam generator in the nuclear power plant stretch across the component cooling water system(CCS) pump building, where some important equipment such as diesel engines and pumps are arranged. Under the double-ended fracture accident of the main feed water pipeline in the CCS pump building, it is necessary to ensure the CCS pumps arranged in the CCS pump building will not loss efficacy due to flooding. However, most of the studies focus on the high-speed jet behavior of the fluid after the pipeline rupture, but less on the accumulation of the jet fluid in the CCS pump building. Moreover, due to the huge size and complex structure of the CCS pump building, experimental study on the prototype size can hardly be carried out. Therefore, three-dimensional numerical calculations were carried out under two types of accidental scenarios, including different pipe broken positions in the 5.334 m floor space and in the pressure compartment between the 11 th wall and the anti-throw wall near the nuclear island, respectively. The simulation results show that under the double-ended fracture accident, the sprayed water drops rapidly within 11 seconds, and the broken positions in the 5.334 m floor space and the pressure compartment will not submerge the CCS pump waterproof platforms. Therefore, this accident will not affect the normal operation of the CCS pump set. The results show that the drainage grid can effectively discharge the overflow water when the breach is located in the space of 5.334 m. When the breach is located in the pressure compartment, the designed steel grid can also effectively discharge the overflow water. This study provides an important reference for the optimal design of the waterproof flooding strategy for the CCS pump building.