And OPPD officials are evaluating the structural supports inside the building that houses the reactor because an engineer discovered last spring that some of the supports aren't strong enough to safely support the building under extreme circumstances.
But OPPD said significant progress has been made at Fort Calhoun, and the utility remains optimistic the plant will be able to restart this spring.
OPPD spokesman Jeff Hanson said the utility isn't concerned about the concerns the NRC raised about Exelon.
"We are satisfied with their performance under our contract to safely and efficiently restart Fort Calhoun Station and achieve sustained excellence at the plant," Hanson said.
Inspectors from the NRC are at Fort Calhoun now checking over the repairs and upgrades that OPPD has made. Regulators will have to sign off on all the work at the plant before it will be allowed to restart.
NRC officials have said repeatedly that they won't allow Fort Calhoun to restart until they are confident it can operate safely.
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NRC page on Fort Calhoun: http://1.usa.gov/GBq2TF
Omaha Public Power District: http://www.oppd.com