A special inspection occurred late last month at the LaSalle Unit 2 nuclear power plant in Marseilles, IL, to review the circumstances surrounding the failure of a valve that could have prevented a safety system from fulfilling its safety function, federal officials said.
During a refueling outage in February, workers discovered a valve in the high pressure core spray system failed to open as designed. Plant operators subsequently determined the valve suffered damage, said officials at the Nuclear Regulatory Commission (NRC). Operators repaired the valve before the plant resumed operation.
The primary function of the high pressure core spray system is to provide cooling water for the reactor in certain accident conditions.
“While this equipment failure did not result in an actual safety event, we have a number of questions our team of specialists will seek to answer, including the technical details of the issue, assessing if plant operators fully understand its causes, and determining if the problem could affect other plants using the same valve design,” said NRC Region III Administrator Cynthia D. Pederson.
The four-member inspection team began work on April 24 and will spend time both on and off site conducting their reviews. A report documenting the team’s findings will be made publicly available within 45 days of the end of the inspection.
The two-reactor facility, operated by Exelon Generation Co., is in Marseilles, IL, about 11 miles southeast of Ottawa.