Omaha Public Power District (OPPD) has postponed restart of its troubled 478-MW Fort Calhoun nuclear plant for the third time since it was shut down 16 months ago. Restart of the reactor, located 19 miles north of Omaha, Neb., requires regulatory approval, and that is now tentatively anticipated early next year.

The company had earlier this spring set the reactor restart date in September. But OPPD spokesperson Jeff Hanson told POWERnews on Monday that the company now plans to heat up the plant by Dec. 1. " By heating the plant, we (and the NRC) can do various inspections and post-maintenance tests to check our work," he said. "This approach will ensure we are completely satisfied the plant is ready for a safe restart after the lengthy shutdown. Safety is our number one priority in this effort."

The 1973-commissioned Fort Calhoun reactor (a 2007 POWER Top Plant) has been offline since April 9, 2011, when it was shut down for a scheduled refueling. Rising flood water from the Missouri River from June to September that year extended the outage. On June 7, 2011, meanwhile, the plant also suffered an electrical fire that was later found to have started in a replacement electrical breaker where poor alignment between components increased electrical resistance on some parts, causing them to heat up and fail. The fire knocked out power to the redundant electrical system, resulting in the loss of spent fuel pool cooling for about 90 minutes.

The Nuclear Regulatory Commission (NRC) this April determined the incident could be characterized as "red"—the highest safety significance—saying it "could have resulted in the loss of a safety function or multiple failures in systems used to mitigate a severe accident." An inspection showed "inadequate maintenance" was to blame in part for the incident. The plant is under a special category for increased NRC oversight given to units that have been shut down for extended periods and have significant performance issues. The plant cannot restart without NRC approval.

OPPD officials last week said that the station has been working to get the plant operational and is working with federal regulators to address issues.

Earlier this month, OPPD contracted Exelon Nuclear Partners, a division of Chicago-based power company Exelon Generation, to manage Fort Calhoun nuclear operations until the plant’s operation license expires in August 2033. OPPD will remain the owner and licensed operator of the plant, but, under the agreement, plant staff will be a blended team of OPPD and Exelon employees.

"While we have made significant progress in our recovery efforts, this operating agreement will help take Fort Calhoun Station to the next level," said W. Gary Gates, president and chief executive officer of OPPD in a statement. Gates added that with application of the "Exelon Nuclear Management Model," a business model, "we can ensure the sustainability and productivity of Fort Calhoun for the future." The arrangement is consistent with other business models being used for single-unit nuclear utilities, he said.

Sources: POWERnews, OPPD, NRC

—Sonal Patel, Senior Writer (@POWERmagazine)