核电厂二次循环冷却水泵房流道水力特性优化研究

二次循环冷却技术是内陆核电建设的关键技术和重点研究方向，泵房流道内良好的水力特性对循环冷却水系统的安全、高效运行至关重要。结合世界首个采用超大型高位收水海水冷却塔二次循环冷却技术的核电项目，开展了循环水泵房流道物理模型试验，模拟分析了流道内流态、水力特性和启停泵过程的水位波动。试验结果表明：采用高位收水冷却塔的二次循环冷却水泵房具有“大取水流量、前池侧向进水、有限容积、高位布置”等特点，在不采取整流措施的条件下，流道内流速分布不均匀，吸水室内偏流严重，吸水喇叭口前存在预旋流，水泵吸水管涡角偏大，影响循环水泵的安全稳定运行。优化方案针对性提出“前池墩栅阵列分水整流+吸水室墩墙联合均流消涡”组合措施，改善了流道和吸水室内流态，满足了循环水泵平顺、均匀进流的要求。此外，根据启停泵水位波动的试验结果，给出了系统充水的最高静水位和启停泵间隔周期建议。研究成果可为后续核电厂二次循环冷却水系统的优化设计提供参考。

Optimization of hydraulic performance in indirect cooling water pump intakes of nuclear power plant

Indirect cooling technology is the primary technology and research focus in the development of inland nuclear power plants.To operate the cooling water system safely and effectively，the pump intake must have good hydraulic performance.the physical model tests of circulating water pump intakes were carried out in conjunction with the world’s first nuclear power project that uses an indirect cooling technology with an ultra-large high level water intake seawater cooling tower in order to simulate and analyze the flow pattern，hydraulic performance，and water level fluctuation caused by the start and stop of the pumps.The test results shows that the indirect cooling water pump intake with high intake cooling tower has the following characteristics：big intake flow，lateral forebay inlet，limited volume，and high layout，among others.The safe and stable operation of the circulating pump is impacted by the uneven velocity distribution in the pump intake，the serious bias in the suction chamber，the pre-swirl in front of the suction bell，and the excessively large vortex angle of the pump’s suction pipe when rectification measures are not taken.The optimization measures are put forward pertinently.Multiple rows of rectification piers are arranged in the forebay to form a grid array，which is used to optimize the flow pattern.Rectification piers and breast walls are arranged in the pump sump to optimize the flow pattern and eliminate eddies.These measures improve the flow pattern of the pump intake，and meet the requirements of a smooth and uniform circulating pump flow.In addition，the maximum static water level of the filling system and the interval period of the start-stop pumps are provided based on the test results of the water level fluctuation of the start-stop pumps.The research results can provide reference for the indirect cooling water system optimization designs in subsequent nuclear power plants.