Analysis Methodology of Clean Agent Fire Extinguishing System Discharge Test for NPP MCR Raised Floor

Since fire in the Main Control Room (MCR) can seriously affect the reactor safety shutdown actions, fire safety equipment is installed to minimize the possibility of fire generation and to suppress the fire. Some of the domestic nuclear power plants have a raised floor structure in the MCR, viewing room of the MCR and the electrical equipment room. A large amount of cables are installed in the raised floor. IG-541 clean agent fire extinguishing system is installed in the lower part of the raised floor to ensure safety in case of fire. When a fire occurs in the raised floor, fire extinguishing should be possible with IG-541 clean agent. A real-scale test facility was constructed to perform a real-scale clean agent fire extinguishing agent test on the lowered area of the raised floor. In this paper, a total of seven test methods were derived after considering the limited test methods for obtaining the optimum concentration of the agent under raised floor from each test. In order to verify the performance of clean agent fire extinguishing system for the raised floor of MCR, seven cases were set up so that the experiment can be performed by controlling the opening ratio of the connection portion with the MCB. The selected cases were combined with 100%, 30%, 0% opening ratio of MCB, initial discharge time (1 or 2 minutes) and extended discharge, respectively. To verify the validity of the gas system fire extinguishing system reliability of the operator habitability by conducting the tests of these seven cases in the future, continuous experiments are needed to obtain valid results and to ensure the reliability of the results.