One man was killed and eight were injured in a crane failure at the Arkansas Nuclear One power plant on 31 March.
The accident happened at 7.50am on 31 March during maintenance at unit 1, an 836 MWe pressurized water reactor. With the reactor in a shut down state for refuelling, crews in the non-nuclear part of the plant were using a heavy lift gantry to move the 500-tonne stator and lower it through a hole in the floor to a waiting multi-axle vehicle.
An unexplained failure caused the gantry to collapse onto the turbine hall floor and the stator to crash through the hole onto the vehicle below. Breaker and switchgear equipment was damaged in the incident causing a loss of power at unit 2, which went into automatic shutdown.
One worker was killed in the accident and a further eight taken to hospital. Two remain there with more serious injuries.
Speaking for plant owner Entergy, Jeff Forbes, executive vice president and chief nuclear officer said: "We are deeply saddened by what has happened today. Our greatest sympathy is with the family and friends of the employee who lost his life, and with those who sustained injuries. I want to express my sorrow and support to all those who work at Arkansas Nuclear One. I know this is especially hard on them."
The loss of power to unit 2 lasted around four minutes and was reported to the Nuclear Regulatory Commission (NRC) as an 'unusual event'. This resulted in an emergency status that lasted until power supplies were stabilised - a period of about ten hours. Essential nuclear safety was maintained despite the accident's knock-on effects on power supply and there was no risk of radiological release.
Entergy's report to the NRC said that "At this time, the full extent of structural damage on unit 1 is not known... Investigation into the cause of the failure and extent of damage is ongoing.
Researched and written
by World Nuclear News