核电站安全壳内乏燃料水池事故工况液位计国产化研发

Domestic Research of Level Gauge of Accident Conditions in Spent Fuel Pool in NPP Containment

田湾核电站VVER堆型机组的乏燃料水池位于安全壳厂房,在严重事故工况下其运行环境极端恶劣,普通型乏燃料水池液位计无法保证对液位状态的可靠监测。由于现用的改进型电容式乏燃料水池液位计运行不稳定且原型仪表停产,田湾核电站基于导波雷达测量技术,研制了一种高可靠性的乏燃料水池液位计。该新型液位计采用分体式结构,配置专用的同轴电缆和独有的测量算法,攻克了分体仪表远距离信号传输、各类运行工况下的测量可靠性以及响应时间要求等研发难点,并且参考1E级电气设备鉴定等级要求完成了各类鉴定试验,满足严重事故工况下安全壳内乏燃料水池液位监测的设计要求,为核电站乏燃料水池液位监测仪表的选型与替代提供了一种国产化的产品。

The spent fuel pool of VVER reactor type units in Tianwan Nuclear Power Station is located in the containment building.Under severe accident conditions,its operating environment is extremely harsh,and the common spent fuel pool level gauge cannot ensure reliable monitoring of liquid level status.Due to the unstable operation of the existing modified capacitive spent fuel pool level gauge and the shutdown of the prototype instrument,Tianwan Nuclear Power Station developed a high reliability spent fuel pool level gauge based on guided wave radar measurement technology.The new type of level gauge adopts a split structure,is equipped with special coaxial cable and unique measurement algorithm,and overcomes research and development difficulties such as long-distance signal transmission of split instruments,measurement reliability under various operating conditions,and response time requirements.And various qualification tests were completed with reference to the requirements of Class 1E electrical equipment qualification level,meeting the design requirements for liquid level monitoring of the spent fuel pool in the containment under severe accident conditions.This provides a domestically produced product for the selection and replacement of liquid level monitoring instruments for the spent fuel pool in nuclear power plants.