冷却剂丧失事故下稳压器波动管及人孔结构的失效机理研究  

Study on Failure Mechanism of Pressurizer Surge Line and Manhole Structure under LOCA

作　　者：余航 赵新文[1] 傅晟威 朱康 Yu Hang;Zhao Xinwen;Fu Shengwei;Zhu Kang(College of Nuclear Science and Technology,Naval University of Engineering,Wuhan,430033,China)

机构地区：[1]海军工程大学核科学技术学院,武汉430033

出　　处：《核动力工程》2023年第1期109-117,共9页Nuclear Power Engineering

摘　　要：稳压器是核反应堆进行压力控制和保护的重要设备,冷却剂丧失事故(LOCA)产生的巨大冲击可能造成其关键部位的结构失效。通过多场耦合计算方法,对小破口LOCA下稳压器波动管的流动传热和结构应力、人孔结构的温度分布和密封性能进行了三维瞬态数值模拟,分析了其失效机理。结果表明:高温流体快速流入波动管形成了巨大的瞬时载荷,造成了管道短时间的强烈振动,管道中间部位变形最大,可能破坏管道支撑结构;各部位等效应力快速增大,与主管道的接管部位出现了集中应力现象,较大的应力波动会影响其寿命;人孔结构出现较大的温度分布不均匀性,密封结构下垫片的密封性能变化最大,在100 s前后其内、外侧密封面接触压力都降至设计密封比压值以下,即出现泄漏。本文根据分析结果提出了波动管和人孔结构的改进建议,可为船用核动力装置发生小破口LOCA后的事故缓解提供技术借鉴。Pressurizer is an important equipment for pressure control and protection in nuclear reactors,and the huge shock generated by loss of coolant accident(LOCA)may cause structural failure of its critical parts.The three-dimensional transient numerical simulation of pressurizer surge line’s flow heat transfer and structural stress,the temperature distribution and sealing performance of manhole structure under the small break LOCA are carried out by the multi-field coupling method,and the failure mechanism is analyzed.The results show that the hot fluid rapidly flowing into the surge line forms a huge instantaneous load,causing a short period of strong vibration of the pipe,the middle part of the pipe deformation is the largest,which may destroy the pipe support structure;The equivalent stress of each part increases rapidly,and concentrated stress occurs at the connecting pipe part of the main pipe.Large stress fluctuation will affect its service life;The manhole structure has a large uneven temperature distribution,and the sealing performance of the gasket under the sealing structure changes the most.The contact pressure of the inner and outer sealing surfaces drops below the design sealing specific pressure before and after 100 seconds,which means leakage occurs.According to the analysis results,this paper puts forward some suggestions for improving the structure of surge line and manhole,which can provide technical reference for accident mitigation after small break LOCA in marine nuclear power plant.

关 键 词：船用核动力装置 LOCA 稳压器波动管 人孔结构 失效机理 

分 类 号：TL353.11[核科学技术—核技术及应用]