Nuclear power plant probabilistic safety assessment by fuzzy approach: current states, future research directions and challenges

Probabilistic safety assessment (PSA) has been widely implemented in nuclear power plant (NPP) safety analysis. In PSA, all events are always assumed to have their own historical failure data. This becomes the technical challenge in PSA. To deal with this limitation, fuzzy PSA has been proposed. Fuzzy concept is introduced to model system reliability when quantitative historical failure data is limited or unavailable. This study reviews the implementation of fuzzy fault tree analysis and fuzzy event tree analysis in NPP safety assessment. To stimulate further research directions, the limitations of existing fuzzy PSA and challenges for future studies are also discussed. The study confirms that fuzzy PSA offers some features to overcome the constraints of conventional PSA. Nevertheless, fuzzy PSA still has some challenges to be dealt with. To improve the capabilities of fuzzy PSA in the future, those limitations and challenges still need to be practically and scientifically overcome.