某项目安注管线热棘轮效应分析与评定

摘要

核电站在运行期间,核反应堆的压力容器和管道会承受内压、循环热载荷及振动等各种复杂载荷工况,这些工况会导致材料或结构发生棘轮效应,缩减材料或结构的疲劳寿命,严重影响压力容器和管道的安全可靠性.RCC-M规范中对压水堆核电站管道的热棘轮效应是基于BREE图进行规定的,计算发现,当管道受到很大热冲击瞬态载荷时,可能会出现不能满足此规范要求的情况,这时就需要进一步对管道棘轮安定性进行分析.分析RCC-M规范对于管道热棘轮的计算公式及评定要求后发现,可以采用薄壁圆筒近似公式对管道棘轮效应进行评价,分析结果表明,在循环热冲击载荷作用下产生的热棘轮效应能够满足RCC-M规范要求,对工程设计有一定参考价值.%The pressure vessels and pipelines of the nuclear reactor bears various complex load conditions such as internal pressure,circulating heat loads and vibrations during the operation of the nuclear power plant,which will cause ratcheting effect to reduce the fatigue life of the material or structure,seriously affecting the safety and reliability of the pressure vessels and pipelines.The RCC-M code about the thermal ratchet effect of the PWR nuclear power plant is based on the BREE diagram.It is found that when a pipeline is subjected to a large thermal shock transient load,it may not meets the requirements of this specification,and further analysis of the stability of the pipe ratchet is necessary.This paper analyzed the RCC-M code for the calculation formula and evaluation requirements of the pipe thermal ratchet effect.It can be found that the ratcheting effect of the pipe can be evaluated by the thin-wall cylinder approximation formula.The results show that the thermal ratcheting effect produced by cyclic thermal shock able to meet the RCC-M code requirements.The project design has a certain reference value.