Public Service Enterprise Group (PSEG) has turned off the unit 1 reactor at the 1,174MW Salem nuclear power plant in New Jersey, US on 30 April 2012.
The reactor was turned off after the declaration of an unusual event due to multiple fire alarms involving the containment building.
The US Nuclear Regulatory Commission spokesman Neil Sheehan was quoted by Reuters as saying that the unit had experienced an inadvertent safety injection and reactor trip during reactor protection system testing.
PSEG spokesman Joseph Delmar said, "A return to service is unavailable at this time."
Unit 2 at the Salem nuclear power plant was not impacted and continued to remain at full power, reports Reuters.