基于塑性极限载荷的奥氏体不锈钢钢承压管道役致裂纹接受标准研究

STUDY ON ACCEPTANCE CRITERIA OF SERVICE INDUCED CRACKS FOR AUSTENITIC STAINLESS STEEL PIPING BASED ON PLASTIC LIMIT LOAD CRITERIA

为保证核电厂长期安全、高效运行,需制订一回路承压边界管道役致裂纹的接受标准,以满足工程上的快速评估需要。对于含裂纹的承压管道,通常需要进行复杂的断裂评价和极限载荷分析。通过数值仿真分析,论证了对于断裂韧性较好的奥氏体不锈钢结构,采用塑性极限载荷作为结构临界状态的合理性,并基于结构设计塑性极限载荷不降低的准则,制订了奥氏体不锈钢管道役致裂纹的接受标准。研究表明,确定的一回路奥氏体不锈钢承压直管段的役致裂纹接受尺寸与美国ASME规范提供数据接近,但明显高于法国RSE-M规范相关数据,法国RSE-M提供的数据过于保守。

In order to ensure safety and efficient state of nuclear power plant in the long time operation,it is necessary to figure out the acceptance table of defects of the primary loop to meet the requirement of rapid assessment in engineering.It is necessary to do the fracture mechanics and plastic limit load analysis for the cracked pipe.Through numerical simulation analysis,the rationality of adopting plastic limit load as the critical state of austenitic stainless steel structure with good fracture toughness is demonstrated.Based on the criterion of non-decreasing the plastic limit load in design state,the acceptance standard of defects for the austenitic stainless steel pipe is established in this paper.The results show that the defect acceptance size of the primary circuit pipe is close to that in the ASME code,but much larger than that of the RSE-M code,and the RSE-M code is too conservative.