核电设备快断安全分析中的热效应影响研究

Study on the Effect of Thermal Effect in Rapid Fracture Safety Analysis of Nuclear Power Equipment

核电设备的快断分析是力学安全分析中重要的组成部分。在热机耦合分析中,热边界的变化对安全分析有重要的影响。利用RCC-M规范在进行快速断裂评判中,热边界关系着安全分析的失效模式和评定限值的变化。以蒸汽发生器下部封头为例,结合RCC-M规范和有限元软件开展了虚拟紧急工况下的快速断裂安全分析研究,并讨论了热边界对分析结果的影响。研究表明:热边界参量(换热系数)的变化会影响快断失效模式和评定限值;RCC-M规范在核电设备快断分析方面有较高的安全因子。

The safety is the lifeline on the development of nuclear power plant(NPP).The fast fracture analysis of nuclear power equipment is regarded as an indispensable part of mechanical safety analysis.For the thermo-mechanical coupling analysis technique,the change of thermal boundary has an important influence on the safety analysis.In the fast fracture evaluation by using the RCC-M standard,failure modes and limit values are related to the variety of thermal boundaries.Taking the lower head of steam generator(SG)as example,the fast fracture safety analysis with considering the virtual emergency condition is studied in detail based on the RCC-M standard and the finite element software,where the effect of thermal boundary on the analytical results is discussed deeply in the present study.Research shows that the change of thermal boundary parameters such as the heat transfer coefficient would affect the failure mode and the limit value.Then,the study further points out that the high safety factor for the fast fracture of nuclear power equipment exists in the RCC-M standard.