不可凝气体对中压安注系统的影响分析研究

Analysis on the Influence of Non-condensable Gas on the Medium Pressure Safety Injection System

2008年,NRC发布公开信GL2008-01“Managing Gas Accumulation in Emergency Core Cooling,Decay Heat Removal,and Containment Spray Systems”,要求核电厂执照申请者必须提供电厂对不可凝气体的应对措施,并证明电厂的设计建造等满足公开信的要求。核电厂发生丧失冷却剂事故下,安全注入系统启动,将含硼水注入到反应堆冷却剂系统,防止堆芯裸露,限制燃料包壳温度的峰值。核电厂正常运行期间,安全注入系统处于满水备用状态。如果系统内产生、积聚不可凝气体,可能导致事故后安全注入系统无法立即投使,进而影响核电厂的安全运行。因此,必须对核电厂安全注入系统不可凝气体问题引起足够的重视。目前,关于该领域的研究工作主要涉及不可凝气体在流体系统中集聚可能影响泵性能甚至导致其无法执行安全功能,主要导致的故障包括:泵气缚、泵突然抱死和泵机械性能降级。对于泵后的系统管道含不可凝气体的水锤现象研究较少。因此研究安全注入系统不可凝气体的水锤分析问题,分析潜在不可凝气体对安全注入系统注入功能的影响对核电厂的安全运行具有重要意义。

In 2008,NRC releases the open letter GL2008-01 "Managing Gas Accumulation in Emergency Core Cooling,Decay Heat Removal,and Containment Spray Systems",which requires nuclear power plant license applicants to provide the response measures to non-condensable gases and demonstrate that the plant's design and construction meet the requirements of the open letter.In the event of the loss of coolant accident in a nuclear power plant,the safety injection system is activated to inject the boron-containing water into the reactor coolant system to prevent core exposure and limit the peak temperature of the fuel cladding.During the normal operation of nuclear power plant,the safety injection system is in the standby state of full water.If non-condensable gas is generated and accumulated in the system,it may cause the safety system to be unable to operate immediately after the accident,affecting the safe operation of the nuclear power plant.Therefore,enough attention must be paid to the problem of non-condensable gas in the safety injection system of nuclear power plant.At present,the research work in this area mainly involves that the accumulation of non-condensable gas in the fluid system,which may affect the pump performance and even lead to failure to perform safety functions,the main failures include:pump air binding,pump sudden locking,and pump mechanical degradation.The phenomenon of water hammer containing non-condensable gas in the system pipeline behind pump is less studied.Therefore,it is of great significance for the safe operation of nuclear power plant to study the water hammer analysis of non-condensable gas in the safety injection system and analyze the influence of potential non-condensable gas on the inj ection function of the safety injection system.