Modeling of Cabinet Fire in Switchgear Room Using Fire Dynamic Simulator

NFPA 805, which provides a comprehensive, risk-informed, performance-based standard for fire protection, and ASME PRA standard, which describes the technical element of PRA, require performing uncertainty analysis in detailed fire modeling. NFPA 805 specifies the set of fire scenarios for each plant area; maximum expected fire scenarios (MEFS) and limiting fire scenarios (LFS). The MEFS are scenarios that represent the most challenging fire that could be reasonably anticipated for the occupancy type and conditions in the space. The LFS is scenario(s) that result in unfavorable consequences with respect to the performance criteria being considered. The actual evaluation of the margin between the MFES and the LFS provides a means of identifying weakness in the analysis where a small change in a model input could indicate an unacceptable change in the consequence. In this paper, cabinet fire in switchgear room of nuclear power plants presented in NUREG-1934 was simulated to identify the cable damage time and to evaluate cable temperature using Fire Dynamics Simulator (FDS) 5.5. Uncertainty analysis of input parameters for fire simulation was also performed to predict the uncertainty ranges of cable damage time and maximum cable temperature. In this study, the MFES was assumed to be fire scenario presented in NUREG-1934. The LFS could be evaluated through uncertainty analyses