核电厂核取样系统取样屏蔽桥不适用问题分析和处理

Analysis and Treatment of the Inapplicability of the Shielded Bridge for Sampling in the Nuclear Sampling System

核电厂核取样系统(REN)事故后取样管线可保证在事故后工况下,用注射器从配有橡皮塞的铅屏蔽桥中抽取少量样品,用于放射性分析测量。福建福清核电厂4台机组自商运以来,REN事故后取样管线取样一直是一个难点,原因在于该操作本身具有时限性,需将REN在线硼表断开。若无法在规定的时间内完工,将影响一回路冷却剂硼浓度的连续监测,产生运行事件。再加上屏蔽桥操作难度较大,无法保证在事故后工况下,能够快速投运取样管线。文章分析了福清核电4台机组屏蔽桥不适用的主要原因,并给出了应对措施。此问题普遍存在于M310型压水堆核电机组,供其他同类型核电厂参考。

The sampling pipeline of the nuclear sampling system(REN)of nuclear power plant after accident ensures that under the post-accident working conditions,a small amount of samples are taken from the lead shielded bridge with rubber plugs with syringes for radioactivity analysis and measurement.Since the commercial operation of the four units of Fujian Fuqing Nuclear Power Co.,Ltd.,the sampling by the sampling pipeline of the REN after accident has always been a problem.The reason is that the operation has timeliness,which needs to disconnect the on-line boron meter.Failure to complete the operation within the specified time period will affect continuous monitoring of coolant boron concentration of the primary loop,and cause an operational event.Moreover,the shielded bridge operation is more difficult,it cannot be ensured that the pipeline can be put into operation quickly after the accident.This paper analyzes the main reason why shielded bridges of four units of Fuqing nuclear power plant are not applicable,and countermeasures are given.And this problem is popular in M310 type PWR nuclear power planst,which can be made reference for other power plants of the same type.