Waterford - The Unit 2 reactor at the Millstone Power Station began producing electricity again about 8 p.m. Wednesday, after being shut down for four days.

Plant spokesman Ken Holt said Thursday that the plant was restarted after crews found that a small piece of metal had become lodged in a water pump, interfering with the flow of water through the pump. The plant was shut down Saturday afternoon after the pump, a backup for the main pump that recirculates water through the turbine generators, failed routine testing. The piece of metal was removed and was sent out of the plant for analysis to determine its origin, Holt said. There was no damage to the pump.

Millstone 3, the other working nuclear reactor at the site, was not affected by the shutdown.

This was the fourth time this year that Unit 2 has been shut down.