基于能量最小化准则的RPV堆芯筒体段断裂安全评估

Fracture Safety Assessment of RPV Core Segment Based on the Energy Minimization Criterion

压水堆核电站反应堆压力容器(RPV)辐照脆化问题是制约其长期安全服役的主要因素之一,如何精确预测其断裂行为是行业的技术难点。首先研究了一种基于能量的新型脆性断裂准则(G_(p)准则),论述了该准则可考虑裂纹尖端的拘束效应和卸载效应;然后采用标准拉伸试样测试了材料拉伸性能,基于CT试样测试获得其断裂临界载荷,进行断裂参量计算、断裂韧度预测及断裂评价准则等内容研究;最后针对某RPV堆芯筒体段进行工程案例示范应用。研究结果表明,初步建立的G_(p)断裂评价准则可进行工程实际应用,在工程案例输入瞬态载荷下RPV堆芯结构是安全的。

RPV’s irradiation embrittlement is one of the main factors which restricting long-term operation of PWR nuclear power plants.Accurately predicting its fracture behavior troubles the industry technically.In this paper,a new energy-based brittle fracture criterion(G_(p) criterion)was studied,which can take into account the constraint effect and unloading effect of the crack tip.Then,the tensile properties of the material were tested by standard tensile samples,and the critical load of fracture was obtained based on CT specimen and the calculation of fracture parameters,prediction of fracture toughness and fracture evaluation criteria were studied.Finally,an engineering application was carried out for a RPV core cylinder section.The results show that,the preliminary G_(p) fracture evaluation criteria can be used in engineering practice,and the RPV core structure is safe under the transient load input in the engineering case.