In order to better understand the situation that occurred at Calvert Cliffs, TheBAYNET.com inquired of the Nuclear Regulatory Commission for an explanation about the failed component and the dangers of that failure. What follows is the response received from the NRC:

There was no danger to the public or plant workers due to the shutdown of the Calvert Cliffs 1 nuclear power plant that occurred last night. Constellation, the plant's owner, made a decision to shut down the reactor to replace a faulty containment building air cooler (i.e., air conditioning unit). (The containment building houses the reactor and related equipment.) There was a Limiting Condition of Operation (LCO) in effect. That is, when the air cooler failed, the company had a fixed period of time in which to fix or replace it. As a result, the unit was taken off-line to allow that work.

Our Resident Inspectors assigned to Calvert Cliffs are closely monitoring the work on installing a new containment air cooler.

At approximately 9 p.m. on Wednesday, July 15, the Unit One reactor at Calvert Cliffs Nuclear Power Generating Facility experienced a technical problem that caused what is termed a forced outage. The shut down effectively reduces the power delivery to the grid to 50 percent of normal capacity from the Lusby plant.

According to Kevin Thornton, a spokesperson for Constellation Energy, operators of the plant, “We experienced a failure of one of four cooling fans on the Unit 1 reactor and because of Nuclear Regulatory Commission regulatory requirements, had to shut the unit down.”

Thornton explained that the shut down is a precaution and that the plant still had three other ‘Containment Air Cooler’ fans in operation. “At no time was there ever any danger to the public,” said Thornton.

The spokesperson went on to explain that it is difficult to say with any certainty how long the unit will remain out of service even though fixing or replacing the CAC is a relatively minor operation.

“These things are hard to predict,” said Thornton. “Also, even when back on line, nuclear reactors do not come up to full power for a day or two.”

Thornton indicated that the power-consuming public was not affected and will not be during the time the reactor is down. Constellation’s power delivery drop was replaced with other power sources supplying the grid as soon as the outage occurred.

“Constellation is responsible by contract to cover the added expense of the alternate energy while the reactor is down,” said Thornton.