As the eyes and ears of the NRC, resident inspectors never know when they might have to respond to an emergency at the plants they monitor. Fred Sanchez, Arkansas Nuclear One Senior Resident Inspector, was preparing to attend Easter services with his family when he got a call shortly before 8 a.m. Sunday informing him that a 600-ton component was dropped from a crane while being moved out of the turbine building at Unit 1.
He drove to the plant to survey the damage and phoned reports back to Region IV staff all day.
The industrial accident resulted in eight injuries and one fatality. Of the injured workers, six were treated and released from a local hospital; two remain hospitalized.
At the time of the event, Unit 1 was in a refueling outage with all of the fuel still in the reactor vessel, safely cooled. The accident damaged some electrical equipment that supplies off-site power to the plant. The plant’s emergency diesel generators started and power was quickly restored to the decay heat removal systems.
Unit 2, which was operating at full power, automatically shut down when power was lost to a reactor coolant pump due to electrical equipment that was damaged when the component fell. At 9:22 a.m. offsite power to one electrical bus was lost because water from a fire main broken by the falling component caused a short circuit. An emergency diesel generator started up and is supplying power to key safety systems. Unit 2 is cooling down using natural circulation.
Both plants are in stable shutdown condition. There was no radiological release or danger to the public.
Entergy Operations, Inc., which operates the plant, declared a Notice of Unusual Event, the lowest of four NRC emergency classifications, at 10:44 a.m. because the accident damaged some electrical equipment. The Unusual Event was terminated at 6:21 p.m. after the licensee took corrective actions to stabilize the plant’s power supplies.
Two additional inspectors have been dispatched to ANO to assist the resident inspectors and conduct follow-up reviews of the licensee’s response to the event. NRC’s Region IV also plans to conduct an inspection to review the circumstances contributing to the event.