秦山第二核电厂3、4号机组RIS系统硼酸再循环回路问题分析及探索

Analysis and Exploration of the Boric Acid Recirculation Loop in the RIS Systems of Unit 3 and 4 of Qinshan No.2 Nuclear Power Plant

针对秦山第二核电厂3、4号机组RIS系统硼酸波动箱房间存在大量硼结晶、硼酸再循环回路运行温度较高、硼酸波动箱液位下降过快造成频繁补水的一系列问题及后果,分析出了硼酸波动箱溢流管线造成空气通路、硼酸再循环泵工作产热大、硼酸波动箱保温层设计不合理等根本原因,并通过对波动箱溢流管线加装盲板及手动球阀、拆除波动箱保温层及使用临时风机等措施取得了明显的效果;又通过探索新增电加热器逻辑、再循环泵换型、硼酸波动箱房间增加进风口和更改波动箱补水阀位置等方案进一步优化RIS硼酸再循环回路的可靠稳定运行。

This paper analyzed the root causes of large working heat dissipation of the boric acid recirculation pump,unreasonable design of heat insulation layer of the boric acid surge tank and the air conduction due to the overflow pipeline of the boric acid surge tank by focusing on a series of problems,like high operating temperature of the boric acid recirculation loop,a large amount of boron crystallization in the boric acid surge tank chamber,frequently water replenishing due to the boric acid surge tank's liquid level drops too fast in 3,4 Unit 3&4 of Qinshan 2.And remarkable results have been achieved by equipping with the blind plate and the manual ball valve for the overflow pipeline of the boric acid surge tank,removing the heat insulation layer and using the temporary fan.In the final part of this paper,the reliable and stable operation of the boric acid recirculation loop is further optimized by adding the logic of electric heater,changing the type of the boric acid recirculation pump,adding air intake in the boric acid surge tank chamber and changing the position of the water supply valve,etc.