China Experimental Fast Reactor Reactor Hall Sodium Fire A Psa Study

Sodium fire has been unavoidable accident in LMFBRs. The research of NPP safety worldwide showed that the event of low risk, such as fire, can be a major contributor to NPP risk. Sodium fire may result in common course failure of many instruments. Furthermore, the fire could destroy the components safety relationship, and lead to more severe sequence. However, there are considerable uncertainties in the result of these researches, due to significant gaps in current abilities to perform realistic fire risk assessment.DBA analysis methods have been applied in the past sodium fire study of CEFR, which is the first LMFBR built in China. The event of sodium fire in Room 501 has not been mentioned because of the low risk of the double-deck second loop tube. There will be performed a Level 1 PSA to estimate the potential risk in the paper.First, the frequency and distribution of initial event were figured out, and the responding characteristics of the systems related were given. Then, the event trees and fault trees were built. Computational codes were adopted to simulate the sodium fire scenarios and provide the conditional failure rate of the wires and components in the fire boundaries. Afterward, the function events were modified, and finally core damage frequency was received.The final results are the following:The frequency of Room 501 sodium fire is 5.60E-3 per year;The CDF due to Room 501 sodium fire is 1.19E-9 per year, the risk is acceptable;The most severe sequence is which MHC single ring is unavailable combined with the invalidation of DHRS;The factors of the failure of the weld line and the air cooling implement of DHRS are the major contributors to CDF.