The financial support by Natural Science Foundation of China (71371070, 71071051, 71301069, 51674145) and Scientific Research Program supported by Lingdong Nuclear Power Plant (KR70543) and Innovation Ability Construction Projects based on the new Industry-Academy-Research Cooperation of Hunan Province (2012GK4101) and Construct Program of the Key Discipline (1201) in Hunan Province (Management Science and Engineering), Postdoctoral Science Foundation of China (2016M600633), Natural Science Foundation of Hunan Province (2017-260), Humanities and Social Science Projects of Ministry of Education(11YJC630207), Program of China Scholarship Council (CSC) and Social Science Projects of Hunan Province (16YBA314) are gratefully acknowledged. We would like to express gratitude to the staff in two Chinese nuclear power plants (Qinshan Phase 3 and Lingdong) for the interviews and investigations which facilitate the research included in this paper. The anonymous reviewers and the editor of this paper are also gratefully acknowledged for their constructive comments and suggestions.