The Nuclear Regulatory Commission is paying close attention to an incident at Nine Mile Two that forced the plant to be shut down over the weekend.
Packing around a valve that is part of the nuclear reactor’s coolant pump was found to be leaking early Saturday morning, the NRC reports.
The leaking water was first found in the drywell that surrounds the reactor and its pipes and was eventually traced back to the valve packing.
The leak was exceeding 10 gallons of water a minute.
Operators at the nuclear plant shut down the plant and declared an unusual event. That’s the lowest of four levels of emergency.
The unusual event ended at about 11:30 Saturday morning when the reactor had been shut down while still under pressure and heated. Later, operators cooled and relieved pressure on the reactor.
NRC spokesman Neil Sheehan reports the agency sent an inspector to the plant not long after the unusual event was declared. The inspector reported that safety measures were in place and effective.
The agency intends to count this event as a mark against the plant’s performance. Three such marks within 7,000 hours of operation and the NRC would increase its level of inspection at the plant.
This will be the first mark on Nine Mile Two’s performance during that time period, the NRC said.