Regulatory framework for nuclear power plant fire safety and risk assessments from global perspective

Abstract

The evolution of regulatory framework for fire safety and risk assessments at Nuclear Power Plants (NPPs) is on-going globally. The first generation commercial NPPs were designed and operated with minimal radiological risk posed by fire, as evidenced by the Brown Ferry (Alabama) NPP station cable tray accident in 1975. The present-ation provides global perspective of insights and integration of fire safety in the planning, design, construction, and operation of NPPs, with the aim for setting up safety regulations, particularly for countries embarking to oper-ate NPPs. Prescriptive fire safety regulations were instituted for commercial NPPs already in operation before 1979, leading to significant modification. The implementation challenges and cost of modifications provided sch-emes for voluntary risk-informed regulations. Since then, the regulatory framework has evolved from prescriptive to risk-informed performance-based assessments, with integrated system of combining deterministic and probabil-istic approaches, and other requirements in risk-informed decision making at the nuclear facility. From global per-spectives and experiences, such system-wide regulatory framework would identify generic issues of fire safety which could be resolved through design, construction and operation of NPPs by applications of risk-informed methodologies.

Keywords: Prescriptive Regulation, Risk-informed Decision, Performance-based Assessment, Deterministic Approach, Defense-in-Depth, Probabilistic Safety and Risk Assessments, Suppressants