Abstract
Maanshan NPP unit 1 happened a 3A fire accident the fire was successfully extinguished by the carbon dioxide fire suppression system in control building .However, fire’s smoke and carbon dioxide fire extinguishing agents were flow and diffusion in control building caused equipment damage and personnel safety problems and made it hard to control the fire situations and increase the difficulties of supply power after fire accidents. Although this accident occurred in the Maanshan nuclear plant, but other nuclear power plants in Taiwan do not rule out the likelihood accidents. It’s important to ensure that the similar fire accidents happen at Chinshan nuclear power plant would not cause equipment damage and personnel safety problems. In this study, a 3D transient model is established for simulation of the diffusion path of smoke and gaseous suppressant (CO2) in the Chinshan NPP’s combination building when fire disaster is occurred. The simulation tool is FDS (Fire Dynamics Simulator) developed by NIST. The 3D transient model contains large objects and HVAC systems in the combination building. The analysis chooses the conservative conditions as some assumptions and initial conditions of the simulation. The study modifies the SFPE (Society of Fire Protection Engineers) safety standards to decide the fire zones are safety for human or not. Each fire zone could be analyzed by two situations under the different scenarios, the result of each situation affect the other regions fire zones and operators in control room. Fire will produce high temperature and high pressure and the automatic fire extinguishing system activated would injected high concentration CO2 are danger factors. In this study discuss the two factors how to affect the movement of smoke particles and carbon dioxide and the change of the safe indicators, each factor will cause different impact of control room. This paper only contains the consequences of fire zone 5 and fire zone 7, the results from the consequences are (1) the safe regions are varied with the location of events, (2) the diffusion velocity of smoke will be different due to CO2 injected, (3) the control room is danger region at the end of simulation (under the accidents happen at fire zone 7 situation).