核电厂安全壳隔离阀密封性试验的影响因素分析及应对

Analysis of Influencing Factors and Countermeasures for the Sealing Test of Containment Isolation Valves in Nuclear Power Plants

在核事故工况下,核电厂安全壳隔离阀承担对安全壳密封、限制放射性物质释放到环境的重要功能。为确保阀门密封性能,核电厂定期执行阀门试验测量阀门泄漏率,而边界阀门泄漏、异物引入、试验压力偏高等对阀门试验影响较为显著。本文基于阀门试验模型及原理针对上述影响因素进行分析,并提出解决措施。通过采取分区查漏、加压吹扫密封面、敲击及解体阀门方法解决边界阀门泄漏、异物卡涩阀瓣等对试验的干扰,上述解决措施实施效果良好,值得推广应用。对于隔离阀试验压力偏高和试验期间泄压验证的高风险问题,可将阀门下游压力引压至上游后再进行压力调节和泄漏率测量,并提出拆除管道射线检查插塞进行泄压验证的创新思路。

In the event of a nuclear accident,the containment isolation valve of a nuclear power plant plays an important role in sealing the containment and limiting the release of radioactive substances into the environment.To ensure the sealing performance of the valve,the nuclear power plant regularly con-ducts valve tests to measure the valve leakage rate.Boundary valve leakage,foreign object introduction,high test pressure have a significant impact on valve testing.This article analyzes the above influencing factors based on valve test models and principles,and proposes solutions.By adopting partition leak de-tection,pressurized blowing of sealing surfaces,tapping and dismantling of valves,the interference of boundary valve leakage,foreign object jamming of valve discs and other factors on the test can be solved.The above solutions have achieved good results and are worth promoting and applying.For the high-risk issues of high test pressure and pressure relief verification during the isolation valve test,the downstream pressure of the valve can be pressurized upstream before pressure regulation and leakage rate measurement,and an innovative idea of removing pipeline radiographic inspection plugs for pres-sure relief verification can be proposed.