China Experimental Fast Reactor Radioactive Sodium Fire Risk Analysis,

China Experimental Fast Reactor (CEFR) is the first sodium-cooled fast reactor of China. The main features include reactor core, heat transform system and engineering safety features, etc. is very different from PWR. Through the safety analysis of CEFR, it was found that the accident of"sodium leak of primary sodium purification system." may induce the radioactive risk to the public and environment. This paper analyzed the accident's radioactive risk and gives some advice to decrease the risk.The confinement system is the last substantiality barrier of CEFR that ventilation systems are the main active part of it. The environment consequence of sodium fire is relied on the reliability of ventilation systems. Based on the probabilistic safety assessment, the inner-cell 309/1 was choosen as the leak site to analyze the sodium leak accident. In this paper, "Event tree-Fault tree model"was built to analyze the accident sequence frequency, sodium fire calculation data and the code AERO was used to calculate radioactive consequence.Conclusion: The accident's public risk is 1.54×10^-11 mSv /year and the maximum value is 5×10^-10 mSv /year .The plant risk is 3.28×10^-7 Ci /year and the maximum value is 2×10^-6Ci/year. During this accident, the unavailability of PTL74 system is 7.7×10^-8/demand,the unavailability of PTL76 system is 1.56×10^-3/demand.The sodium fire accident's risk is acceptable and the ventilation systems are reliable. The analysis shows that human factor, maintain during reactor shutdown period, fireproofing valve's temperature common factor and electricity supply factor are the most important factors to ventilation systems' reliability.