Specialists from the U.S. Nuclear Regulatory Commission are conducting a special inspection at the Cooper Nuclear Station near Brownville, Neb., in response to the failure of a pipe that supplies lubricating oil to an emergency diesel generator.
The diesel generators supply power to plant safety systems in case of a loss of off-site power during emergencies. Nebraska Public Power District operates the plant. During a monthly surveillance test of the diesel generator Jan. 27, the commission said, the pipe began leaking oil, which the licensee said was caused by a vibration-induced failure.
A year ago, the NRC said, a leak was found in a similar pipe supplying oil to a second emergency diesel generator. The licensee replaced pipes on both diesel generators.
Based on this most recent leak, and the similarity of the problems, we have questions about the effectiveness of the licensees corrective actions and we want to take a closer look at this matter, said NRC Region IV Administrator Elmo Collins.
A four member team of NRC specialists will review the circumstances related to the event, the licensees root cause evaluation and determine whether the Nebraska Public Power District took appropriate corrective actions. The team includes three reactor inspects from the NRCs Region IV office in Arlington, Texas, and a member of the Office of Nuclear Regulatory Research from NRC headquarters in Rockville, Md.
NRC said the inspection began Feb. 23 and was expected to take several days. The team will write a report about 30-45 days after completion of the inspection.