PSEG NUCLEAR.JPG

The Salem 1 and Salem 2 nuclear reactors at PSEG Nuclear's generating station on Artificial Island in Lower Alloways Creek Township are seen in this file photo. An "unusual event" was declared after a faulty fire detector went off Saturday night.

(Times File Photo)

LOWER ALLOWAYS CREEK TWP. -- An "unusual event" was declared at the Salem 1 nuclear reactor over the weekend after a faulty fire detector went off causing a room to be filled with carbon dioxide, officials said.

The incident took place in the non-nuclear side of the plant in the diesel fuel oil pump transfer rooms.

These pumps would feed diesel fuel to emergency backup generators to provide electricity to the plant in case of the loss of off-site power, according to Joe Delmar, spokesman for the plant's operator, PSEG Nuclear. The pumping rooms are located in an auxiliary building at the plant.

The unusual event was declared by plant operators at 6:22 p.m. Saturday. The all-clear was given at 9:54 p.m.

An unusual event is the lowest of four emergency classifications of emergencies at a nuclear power plant.

When the fire detector activated, it caused the release of carbon dioxide, an asphyxiant, into the rooms. The carbon dioxide is designed to put out fires. However, there was no fire in this case.

The unusual event was declared because the release of the carbon dioxide could have potentially impacted plant operations, but it did not.

Because of the location of the pumping rooms and the fact they were filled with carbon dioxide, they were not immediately accessible to plant operators.

The area was eventually ventilated which allowed personnel to walk through the rooms and confirm there was no fire and all was in order.

An investigation found the detector was indeed faulty, causing it to go off and trigger the carbon dioxide release.

The incident did not affect the fuel pumps.

There was no threat to the employees or the public, officials said.

Salem 1 remained running at full power throughout the unusual event.

Salem 1 is one of three reactors operated by PSEG Nuclear at is Artificial Island generating complex in Lower Alloways Creek Township. The other two are Salem 2 and Hope Creek which are also operating at full power.

The three plants comprise the second-largest nuclear generating complex in the U.S.

Bill Gallo Jr. may be reached at bgallo@njadvancemedia.com. Follow South Jersey Times on Twitter @TheSJTimes. Find the South Jersey Times on Facebook.