Fire risk assessment to develop a compliance strategy for sample redundant electrical panels at a nuclear power plant based on deterministic fire protection requirements

摘要

In this study, the relative risk contribution to develop a compliance strategy of a nuclear power plant designed to a deterministic fire protection standard was assessed using a focused fire probabilistic risk assessment (PRA). Sample redundant electrical panels were selected for the assessment. We suggested a method to estimate all of the required input information values for developing a resolution strategy on the compliance-related issue without using actual PRA information developed in accordance with Part 4 of the ASME/ANS-RA-Sa-2009 PRA standard. The damage time of target cables due to a fire was calculated to quantitatively assess the risk significance of a fire using fire modeling tools including fire dynamics tools (FDTs) and fire dynamics simulator (FDS) 6.5.2. We found an option to resolve the compliance-related issue that is controlling the access to transient ignition sources near fire area where the electrical panels are located through fire modeling analysis. The relatively conservative fire PRA modeling yielded a calculated fire core damage frequency (CDF) of 6.67 E-08/yr. The risk impact of the fire scenario is small and would likely be considered acceptable under a risk information-based regulatory framework.