APR-1400 원전 비상디젤발전기의 신뢰성 개선 분석에 관한 연구

Abstract

Emergency Diesel Generator (hereafter "EDG") of Nuclear Power Plant (hereafter "NPP") automatically starts and supplies safety-related equipment with electric power needed in case of Off-site Power Loss. Therefore, the World Association of Nuclear Operators (WANO) evaluates "In-operability of EDG" by using the Safety Performance Indicator because the reliability of EDG is directly related to the safety of NPP.

The EDG of APR1400 NPP was designed as level as 97.5% of target reliability and 99% of equipment reliability by the accumulation of operation experiences of domestic NPPs and by the improvement of design and manufacturing technique of NPP facilities. Accordingly, this thesis proposes optimized measures for test and operation management process to improve the reliability of EDG in APR1400 NPP and to cope with performance degradation resulted from the elapse of EDG life time by concretely analyzing the elements which are considered that they gave a positive impact on improving the reliability of EDG.

First of all, the starting reliability of APR1400 EDG was verified through the 300 times of successful starting tests. The test results can be evaluated to meet 99% of equipment reliability. The load operation and comprehensive reliability, which are related to verifying 97.5% of target reliability, will be evaluated after two years of commercial operation because they require more than 20 accumulated valid test results.

Finally, test management is very important because the target reliability of EDG can be verified through the periodic performance tests. Consequently, introduction of optimized EDG operation process such as "reliability improvement measure during the starting and load operation" was proposed and the operation reliability of EDG will be improved more in case that this process is applied.