Performance Based Risk Informed Fire Modelling Evaluation of Electrical Equipment Functionality in Nuclear Power Plants

Abstract

Introduction of risk-informed and performance-based analyses into fire protection engineering practice exists in both the general fire protection and the nuclear power plant fire protection applications. Risk-informed and performance-based approach relies on application of validated and verified fire modelling to estimate fire generated effects that are arising in predefined fire scenarios for fire protection related applications in nuclear power plant. Regulatory bodies have used risk-informed insights as a part of its regulatory decision making for the past thirty years. Before performance-based approach came out, all regulatory prescribed requirements relied on deterministic approach with ultimate condition that one complete shutdown train together with auxiliary support features is free of fire damage. Performance-based approach relies upon calculable performance results to be met but provides more flexibility in achieving established performance criteria during all phases of plant operations. Nevertheless, fire modelling is finding its benefits in design basis engineering, fire hazard analysis, nuclear safety capability assessment and probabilistic risk assessment. To demonstrate such capabilities, an example on fire development in Nuclear Power Plant Safety Related Pump Room with respect to possible loss of one safety shutdown path is modelled with a fire simulator computer tool.