疏水问题引发核电机组出力下降实例分析

Example analysis for output decline of nuclear power unit caused by drainage problem

针对某核电站疏水问题引起的机组出力下降,建立了故障排查模型和泄漏量的理论计算模型,研究制定了主蒸汽管线泄漏量测量试验。通过机组启停前后同等运行工况下主蒸汽疏水隔离和投用的热功率、给水流量差值,计算疏水系统的泄漏量。同时利用各种测量手段对疏水故障进行定位,确定了热静力型疏水器的失效模型,表明液位计管线布置和疏水器安装不满足要求导致了主蒸汽疏水系统高液位报警的频发。使用新型自由浮球式疏水器,同时取消了SN液位计下游U型布置、上游倒U型布置。应用效果表明,本文故障分析方法可靠,节能效果良好,可为同类核电厂提供参考。

A model for troubleshooting and a theoretical calculation model of leakage were established to analyze the output decline caused by drainage problem in a nuclear power plant. The leakage rate was calculated by comparing thermal power and feed water flow before and after the unit startup and shutdown under the same operating conditions. In this study, the measurement of a main steam pipeline leakage was conducted, locating the drainage problem by different ways. In addition, the failure model of the thermostatic trap was determined and showed that the pipeline layout of liquid level gauge and the incorrect installation of steam trap leaded to frequent high level alarm of steam trap. At the same time of correcting the pipeline layout, a new free floating trap was used to replace the previous trap. The application result shows the reliability of the fault analysis and better energy saving effect. The analysis, treatment and suggestions of this abnormal output can provide reference for similar nuclear power plants.