Probability Safety Assessment On Cable Fire In MCR For Ling Ao ? NPP

Fire inside the nuclear power plant (NPP) has an important influence to the nuclear safety. Recently, nuclear industry pays more and more attentions to fire probabilistic safety assessment. Ling Ao II NPP employed a digital I&C system and advanced main control room(MCR) technology, and no one has studied on fire PSA for such NPP. Probabilistic safety assessment on cable fire is an important part of MCR fire PSA in our country. There are some sense of engineering technology on this study.Cooperating with the PSA project team of CGN, probabilistic safety assessment on cable self-ignition fire in MCR for Ling Ao ? 3# NPP was completed. Firstly, based on existing fire PSA method, the feature of the advanced MCR was analyzed, and an analysis procedure for fire PSA on MCR was formulated by adopting the NUREG/CR-6850 method. Secondly,according to the analysis procedure, PSA on cable fire in MCR was performed, including the cable fire accident scene analysis, establishment of ET and quantitative analysis of the ET.Lastly, safety assessment and suggestion is given based on the analysis result.According to the detailed fire modeling analysis, time window of operators'none-residence instrument's unavailability after the cable in MCR catching fire was determined. There are 45 sequences in the cable fire ET, of which 2 sequences was transferred to PT1A ET analysis and 31 sequences would cause core damage. The core damage frequency(CDF) by quantitative conclusion is about 1.74E-08 per reactor and year, and the reactor shutdown frequency is 1.92E-08 per reactor and year. The damage of cable fire in MCR would be further reduced by strengthening the training of operator finding the fire accident in-time and improving the accuracy of operator's judgment to the fire accident. The result will make a contribution to the implement of fire PSA for Ling Ao ? NPP.