Progress Energy Florida last week told the Nuclear Regulatory Commission (NRC) and state regulators that Crystal River Nuclear plant has been shut down indefinitely while the company conducts a “thorough engineering analysis and review” of a new gap in the reactor’s containment building wall that resulted from tendon retensioning work.

The company said in a press release that the initial damage occurred in late 2009 in the concrete at the periphery of the containment building while creating an opening in the structure to facilitate the replacement of the steam generators inside.

In mid-March, final retensioning of tendons within the plant’s containment building was suspended while engineers investigated evidence of an additional delamination (or separation). The unit was already shut down for refueling and maintenance at the time the damage was found.

The plant has been shut down since September 2009. “Options to return the plant to service will be analyzed after the report is complete,” the company said. “The company cannot estimate a return to service date for CR3 at this time.”

As of December 2010, repairs had cost the company $150 million, and an additional $290 million are said to have been spent on replacement power costs.

The Crystal River Nuclear Plant, located near Crystal River, Fla., is a Babcock & Wilcox Lowered Loop pressurized water reactor that went into service in March 1977. Its current license expires in 2016, and the company filed for a license renewal with the NRC in 2008, requesting an additional 20 years of operation.

The nuclear unit is part of the 3,151-MW Crystal River station, which also includes four coal units.

Sources: Progress Energy, POWERnews