Comparative Study on the Fire Suppression Performance of Water Mist Systems and Gas-Based Automatic Extinguishing Devices under Nuclear Power Plant Cabinet Fire Conditions

This study compared the fire suppression performance of gas-based automatic extinguishing systems (HFC-125 and FK-5-1-12) and a water mist system for localized cabinet fires in nuclear power plants. Fire tests using n-heptane and diesel were conducted under simulated cabinet fire conditions, and the suppression performance was evaluated based on the activation temperature, extinguishing time, and reignition behavior. The gas-based systems extinguished fires within 11~17 s, whereas the water mist system achieved a comparable performance with extinguishing times of 15~18 s. No reignition was observed in any test case. These findings indicate that the water mist system is a feasible alternative for localized cabinet fire suppression, offering reduced dependency on enclosure conditions compared with gas-based systems.