轻水堆环境影响疲劳相关问题的研讨

美国核管会（NRC）在其管理导则RG 1．207中明确要求新建轻水堆核电厂设计中须考虑环境影响疲劳（Environmental Assisted Fatigue，EAF）问题。目前，我国新建核电厂在部件疲劳评价时尚未考虑EAF的影响。对环境影响疲劳的发展概况、疲劳裂纹和疲劳寿命的定义、ASME 设计疲劳曲线、现有ASME疲劳设计方法的保守性、美国环境影响疲劳设计方法等方面作了探讨，同时根据NUREG／CR 6909中Fen表达式，给出了典型材料在温度、溶解氧浓度和硫含量确定的情况下，Fen与应变速率的关系曲线。通过对以上相关问题的归纳和总结，以期加深业界对核电厂环境影响疲劳问题和现有ASME疲劳设计方法的认识。

Discussions on Related Issues about Environmental Assisted Fatigue for Light Water Reactor

The regulatory guide RG 1 .207 issued by U.S.Nuclear Regulatory Commission （NRC ） required that the environmental assisted fatigue（EAF）issue should be considered for new light-water reactor （LWR）construction.Currently,the LWR environmental effects are not incorporated into fatigue analyses for new LWR construction in China.The EAF issue development history,the definition of fatigue crack and fatigue life,the ASME design fatigue curve,the conservatism for the existing ASME fatigue design approach and U.S.EAF design approach are discussed.Meanwhile,according to the Fen expressions in NUREG/CR 6909,given the certain temperature,dissolved oxygen content and sulfur content,the Fen and strain rate correlation curves for typical materials are presented.The author hopes that the discussions and summarizations for the above issues could deepen the understanding of the EAF issue and existing ASME fatigue design approach for industry colleagues.