Reliability Analysis Of LOOP And SBO Events In Nuclear Power Plant Based On The GO Methodology

As for the nuclear safety issues, reliable power supply plays an important role tosecure nuclear operation. Therefore, AC and DC power should be supplied forimportant facilities inside plant for the sake of maintaining daily operation andproblems caused by nuclear accidents.The GO methodology is a success-oriented system reliability analysis method,especially for dealing with the system of multiple states、time-sequential and flowingsignals. Compared with the other methods, the GO methodology has a better effect. Inthis paper, the two initial events affecting reactor core damage, naming loss of offsitepower (LOOP) and station blackout (SBO) are analysed by using the GOmethodology. Firstly, some basic knowledge about the two initial events, the GOmethod theory and fundamental information about electrical system design areintroduced Then the calculation formula of multi-state system failure rate for GOmethod is derived, new GO operator is created based on the emergency responsebackground, and way, mixing GO method and Markov method together, is found todeal with maintenance-related problem. Finally, quantative and qulitive results suchas reliability probability, frequency and minimal cut sets are made based on theelectrical design of typical nuclear power plant. Furthermore, softwares relate to thispaper are developped, which results in simulating the real dynamic reliability curvesafter LOOP and SBO accidents successfully. Meanwhile, the analysis in this paperconsiders the influence by outside weather condition, which is good to gettingaccurate results. After comparing the GO results with data from reports finished byNRC, the GO quantative results are verified, both accuracy and usefulness in thereliability field of nuclear power supply analysis. Meanwhile, the minimal cut setsand the responding importance degrees discloses the vulanerable spots of nuclearpower plant during generation, then some corrective measures should be taken toachieve higher safety level by operation and maintainance teams, which will also bemeaningful and of great importance in practice.