Diablo Canyon Nuclear Power Station Unit 1 Auxiliary Feedwater System Reliability Study Evaluation

摘要

One of the important safety systems involved in the mitigation of the Three Mile Island accident was determined to be the Auxiliary Feedwater System (AFWS); each operating plant's AFWS was studied and analyzed. The results for Westinghouse designed plants were reported in NUREG-0611. Prior to obtaining an operating license, the applicant for each non-operating plant is required to perform a reliability analysis of his AFWS in a manner similar to the study made in NUREG-0611. Conclusions: (1) Pacific Gas and Electric Company (PG&E) has complied with requirement (b) of an NRC letter which states: '(b) perform a reliability revaluation similar in method to that described in Enclosure 1 that was performed for operating plants and submit it for staff review.' Enclosure 1 to the letter provides the applicable portions of NUREG-0611 which deal with the Auxiliary Feedwater Systems. (2) The PG&E report adequately discussed the major contributors to unreliability for the three cases: (1) LMFW, Loss of Main Feedwater, (2) LMFW/LOOP, Loss of Main Feedwater/Loss of Offsite Power, and (3) LMFW/LAC, Loss of Main Feedwater/Loss of All AC Power.