Repairs to a cracked reactor building containment wall could keep the Crystal River nuclear plant off line until midyear, Progress Energy says.
The company powered down the nuclear plant in September for a major maintenance project that was expected to be finished by late December.
But shortly after the job began, workers discovered that part of the containment wall had separated into two layers. The plant has remained off line since then while the company investigates its cause and comes up with a repair plan.
Progress Energy spokeswomen said Tuesday they cannot predict yet what the repairs to the wall will cost or whether the company will seek to recoup any of the repair costs from customers.
"Way too early to talk about that at this point," Progress Energy spokeswoman Suzanne Grant said.
Both of those questions will depend on what the root cause of the crack is determined to be.
Progress Energy and its engineering contractors have narrowed the list of possible causes from more than 70 to "a handful," according to a one-page update that Progress Energy filed with the Florida Public Service Commission on Jan. 25.
While the analysis of the cause is not complete, Progress Energy's update said "the remaining variables appear to point toward the interplay between several factors."
The determination of the root cause also will affect the schedule for repairs, but Progress Energy told the PSC that "based on what we know at this time, we do expect that all repairs will be completed so that (the plant) will return to service by midyear."
Workers discovered the gap, known as a delamination, while cutting a 25- by 27-foot hole in the wall so that two huge steam generators could be replaced.
The utility cut the hole because the reactor building's regular equipment hatch is too small for the new generators, each of which is 75 feet long and weighs 550 tons.
The wall itself is 42 inches thick, and the gap was found about 9 inches below the outer surface. The investigation has found that the gap inside the wall is up to 2 inches wide and extends up to about 30 feet from where the hole was cut for the generators.
Tests have not found similar gaps in any other part of the containment building.
While many details of the repair plan will depend on what experts determine the root cause of the crack to be, Progress Energy spokeswoman Wendy Horne said the company expects to remove and repour the delaminated concrete.
At this point, however, it does not appear that the repairs will require replacing the steel tendons embedded in the wall, Horne said.
Richard Danielson can be reached at Danielson@sptimes.com or (813) 226-3403.