(A) methodology for a quantitative assessment of safety culture in NPPs based on bayesian networks

Abstract

For a long time, safety has been recognized as a top priority in high-reliability industries such as aviation and nuclear power plants (NPPs). As advanced technology develops, it has been demonstrated by many accidents in the past that software (human) has greater influence on the safety than hardware (equipment). Therefore, the human of an organization should be emphasized in order to enhance the safety in the complex industries. Safety culture plays an important role in such organization software. The concept of safety culture in the nuclear power domain was first established in the International Atomic Energy Agency safety series [1], wherein the importance of employee attitudes for maintaining organizational safety was emphasized. The safety failure in nuclear industries means irreparable performance failure. Therefore, industries have been continuing their efforts to measure the safety culture awareness of workers and to improve the vulnerable areas. Safety culture assessment is a critical step in the process of enhancing safety culture. However, it is very difficult and highly uncertain to measure the safety culture awareness of workers. The results of safety culture assessment are mostly subjective, qualitative and inconsistent. Given the current situation, this paper suggests a quantitative methodology for safety culture assessment based on Bayesian networks. A proposed safety culture framework for NPPs would include the following: (1) a norm system, (2) a safety management system, (3) safety culture awareness of worker, and (4) Worker behavior. The safety culture awareness of workers at NPPs was reasoned through the proposed methodology. Then, vulnerable areas in NPPs were derived quantitatively through sensitivity analysis. The reliability of the suggested model was verified through the application to real accident cases. It is expected that this methodology will help the reduction of time and cost for safety culture assessment in NPPs, and providing the consistent results.