Costly estimates for Crystal River repairs

An independent review of Progress Energy's plan to repair the damaged containment structure of its idled Crystal River nuclear power plant suggests that the cost is likely to be almost $1.5 billion. However, in the worst-case scenario, it could cost almost $3.5 billion and take eight years to complete. The utility has yet to decide whether to repair or retire the unit.

An independent review of Progress Energy's plan to repair the damaged containment structure of its idled Crystal River nuclear power plant suggests that the cost is likely to be almost $1.5 billion. However, in the worst-case scenario, it could cost almost $3.5 billion and take eight years to complete. The utility has yet to decide whether to repair or retire the unit.

Crystal River (Image: Progress)

Some 22 potential repair options for the plant's containment structure were evaluated by Progress and a range of outside experts before it settled on what it thought best: to systematically remove and replace concrete in the affected parts of containment structure walls. This will not include the areas where steam generator holes have already been rebuilt.

Progress, now a subsidiary of Duke Energy, has submitted to the Florida Public Service Commission (PSC) a report from engineering consultants Zapata Inc regarding its independent review of the potential repair plan for unit 3 of the Crystal River plant. Progress commissioned the report in March to further analyze the potential scope, risks, costs and schedule of the prospective repair.

The utility said that the report concluded that the current repair plan "appears to be technically feasible, but significant risks and technical issues still need to be resolved, including the ultimate scope of any repair work." It also estimated the cost of repairing Crystal River at some $1.49 billion. In June 2011, Progress's preliminary cost estimate for the repair was put at between $900 million and $1.3 billion. The report by Zapata also confirmed, as Progress' assessment had indicated, that an increase in the scope of repairs will increase the costs and extend the schedule.

Zapata also produced costs estimates for more extensive work based on potential unplanned scenarios. The worst-case scenario assumed that Progress would undertake its "more limited scope of work, and at the conclusion of that work, additional damage would occur in the dome and in the lower elevations, which would force the replacement of each." Under this scenario, Zapata said that the work could cost some $3.43 billion and take 96 months to complete.

Crystal River is a pressurized water reactor that normally produces 860 MWe, but it has been offline since September 2009 when a refuelling and 20% uprate outage began. A hole was made in the plant's concrete-reinforced steel containment structure for the replacement of its steam generators, but engineers noticed this had caused part of the concrete to delaminate. This was repaired, and the concrete re-tensioned, but the same problem was found in at least one other place with still more areas requiring attention.

The containment stands as a major element of the plant's nuclear safety provision and is over one metre thick, laced with horizontal and vertical steel tendons and lined with steel about one centimetre thick. The delamination was occurring over 20 centimetres into the concrete.

The plant had originally been due to restart in April 2011 following the uprate, but in June 2011 Progress said that it did not expect it to restart until 2014.

Alex Glenn, incoming president of Progress Energy Florida, stressed that the company had yet to make a final decision on whether to repair or retire the Crystal River plant. He noted, "The evolving analysis will provide increasing detail on cost and schedule expectations."

"We will proceed with a repair option only if there is a high degree of confidence that the repair can be successfully completed and licensed within the final estimated costs and schedule, and is in the best interests of our customers, joint owners and investors," Glenn said.

Crystal River 3 began operation in 1977 and is currently licensed to operate until 2016.

Researched and written
by World Nuclear News