A Systematic Review of Reliability and Safety in Nuclear Power Plants

The safe operation of nuclear power plants is a cornerstone of energy security and socioeconomic development, with the reliability of Pressurized Water Reactors (PWR) depending on the effectiveness of inspection and maintenance plans for their critical components. Optimization through Risk-Based Inspection (RBI) has emerged as a key methodology to balance system safety, plant availability, and economic efficiency, by focusing maintenance efforts on the most critical items. The nuclear energy industry has shown growing interest in adopting risk-based approaches to maintenance activities. In this context, this study conducts a Systematic Literature Review (SLR) to map the state of the art in optimizing inspection plans for PWR reactors, with an emphasis on RBI-oriented methods, tools, and perspectives. The review covered scientific publications from the past five years, including articles, technical reports, and international standards. The results reveal a predominance of probabilistic models integrated with tools such as Failure Mode, Effects, and Criticality Analysis (FMECA), Fault Tree Analysis (FTA), and Event Tree Analysis (ETA). Two main research axes were identified: (1) the use of computational simulation and machine learning for maintenance optimization, and (2) the application of RBI or Risk-Informed In-Service Inspection (RIISI), a nuclear industry-specific approach based on principles consistent with RBI. Despite recent advances, the direct application of Probabilistic Risk Assessment (PRA) for the full optimization of inspection plans remains underexplored, highlighting an important research gap for PWR reactors. It is concluded that this is an expanding field with great potential in integrating reliability methods and computational innovations. This work provides an up-to-date overview, serving as a guide for future research and the development of more robust and safer inspection practices.

Keywords: Pressurized Water Reactor (PWR); Inspection Plan Optimization; Risk-Based Inspection (RBI); Reliability Analysis; Probabilistic Risk Assessment (PRA); Nuclear Safety.