There was a special inspection at the Palo Verde Nuclear Generating Station Monday to review circumstances surrounding the failure of an emergency diesel generator during testing on Dec. 15.
Arizona Public Service Co. operates the facility, in Wintersburg, AZ.
“The purpose of this special inspection is to better understand the cause of the failure and to review the adequacy of corrective actions proposed by the licensee,” said Nuclear Regulatory Commission (NRC) Region IV Administrator Kriss Kennedy.
Emergency diesel generators supply power to safety-related systems in the event of a loss of off-site power. NRC requires each of the three reactors at Palo Verde have two emergency diesel generators they must test monthly to ensure operability.
During a scheduled test, a piston failed on one of the emergency diesel generators at Unit 3, prompting the licensee to declare an alert, the second lowest of four levels of nuclear emergency. No site personnel suffered an injury and the alert terminated two hours later. There was no danger to the public and the event had no effect on plant operations.
NRC inspectors will spend about a week on site. The team will also determine whether there are any potential generic implications for the industry and determine whether plant operators’ response to the event was appropriate. An inspection report documenting the team’s findings will be publicly available within 45 days of the end of the inspection.