Indian Point’s Unit 2 reactor shut down for three days after electrical trip

The Unit 2 nuclear reactor at Indian Point Energy Center in Buchanan came back online Dec. 8 after being manually shut down by control room operators Dec. 5 following an electrical short that lowered the voltage affecting some of the control rods.

The loss in power, which involved an electrical breaker malfunction with a roof fan, affected about 10 control rods of the 53 that hover above the reactor by electric-powered magnets. The magnets for those 10 rods lost power and descended ”“ as designed ”“ into the nuclear fuel core within one of the dome-shaped containment buildings Saturday evening.

Control rods are made of materials that absorb neutrons used to control the power and the fission process of a nuclear reactor.

The cause of the trip to the circuit breaker, which is located in a building on the non-nuclear side of the plant, is not yet known and is being investigated, according to Entergy Corp., the owner of the power plant.

Per procedure rules following an unexpected control rod drop, the entire reactor was shut down by Entergy control room employees, which occurred around 5:20 p.m.

A statement from Entergy sent Tuesday evening and announced the reactor”™s restart said, “All control rods and related electrical equipment was tested satisfactorily by Indian Point engineers prior to placing the plant back in service.”

In response to learning of the outage, Gov. Andrew M. Cuomo, who in the past has vowed to shut down Indian Point, released a statement Saturday night that said: “I have directed the state Department of Public Service to investigate and monitor the situation and a team is currently en route to Indian Point to begin its work.”

In an email, Nappi said, “We were happy to provide information to the DPS representative and all stakeholders regarding the plant shutdown Saturday evening.”

Neil Sheehan, a spokesman for the U.S. Nuclear Regulatory Commission, said in an email that NRC resident inspectors have been on site since Saturday evening to regularly check on the plant”™s overall safety and repair activities. Like all nuclear power plants in the country, the NRC has inspectors permanently assigned to each site, including Indian Point.

The Unit 2 reactor had run online for 627 straight days prior to Saturday”™s shutdown. Indian Point”™s other reactor, Unit 3, has been running at 100 percent, but has been shut down for two scheduled and four unscheduled outages in 2015.