OMAHA, Neb. (AP) -- A nuclear reactor in Nebraska, idled for almost two years by a laundry list of problems, is coming under increased regulatory scrutiny due to some bad math in its 40-year-old design and the use of Teflon even though it tends to disintegrate when exposed to high radiation.
The new issues revealed at recent public meetings could further delay the resumption of operations at Fort Calhoun that critics assert is already costing too much to fix and should remain shuttered forever.
The Omaha Public Power District imposed a 6.9 percent increase in electricity rates this month for customers across southeast Nebraska, largely to finance a $143 million bill to fix some 450 problems and rehabilitate the nuclear plant that was closed in April 2011.
But that price tag does not account for the plant's most recent concerns.
The utility says one of its engineers discovered that bad calculations in the design of the plant that opened in 1973 mean that some support structures might not be able to withstand the weight of heavy equipment under extreme stress. Omaha Public Power District officials also are rethinking the use of Teflon to insulate some electrical wires; the utility continued to use Teflon even after experts revealed in 1985 that it tends to disintegrate when subject to high levels of radiation. Fort Calhoun is the only U.S. nuclear plant that still uses Teflon in some places.
"If Fort Calhoun were being run by a business, it would have been shut down a year ago," said Arnie Gundersen, a former licensed reactor operator who works with Fairewinds Energy Education, a nonprofit that studies energy issues.
The utility argues that many of the previously identified complications have been addressed, much of the repair work is complete and that the nation's smallest nuclear plant, on the Missouri River just north of Omaha, should be up and running again by the end of March.
Nuclear Regulatory Commission officials say they won't allow Fort Calhoun to restart until they're confident its safe, and regulators haven't set any timeline for that.
"There's still a lot of work to be done," NRC spokeswoman Lara Uselding said.
Fort Calhoun's closure in April 2011 began with routine refueling maintenance, but massive flooding along the Missouri River that year and several safety and security violations forced it to remain closed.
Among the violations cited by regulators was the failure of a key electrical part during a 2010 test, a small electrical fire in June 2011, several security issues and deficiencies in flood planning that were discovered a year before the river spilled its banks.
Still to be addressed: the repair of flood damage at the facility; the replacement of fire-damaged equipment; strengthening the management of the plant; improving the safety culture among workers; the removal of the Teflon insulation; and the strengthening of heavy equipment supports.
An engineer for the utility discovered the structural concerns last spring when the company was looking into putting additional equipment on one support to boost power output. OPPD spokeswoman Lisa Olson said regulators had reviewed the design of the heavy equipment support structures before the plant was built.
David Lochbaum, director of the Nuclear Safety Project for the nonprofit group Union of Concerned Scientists, said the utility should have caught the structural problems much earlier and that the Nuclear Regulatory Commission might have uncovered them had they conducted more than just spot checks before renewing Fort Calhoun's operating license in 2003.
"There were opportunities to find this sooner," Lochbaum said. "It's embarrassing to find something like this, but not unheard of."
The Nuclear Regulatory Commission sent Omaha Public Power District a notice in 1985 to replace Teflon as insulation in the building housing Fort Calhoun's reactor. The utility subsequently replaced it on wires that it considered at critical risk but left some in places it did not consider a safety concern.
Commission spokeswoman Lara Uselding said her agency's oversight process relies on nuclear plant operators identifying and fixing problems while commission inspectors scrutinize that work. This system, she said, has not been successful at the Omaha plant.
"Historically at Fort Calhoun, that has not gone well and that is why they are currently under increased oversight," Uselding said.
Acknowledging the deterioration of performance at Fort Calhoun before the shutdown, the utility signed a 20-year deal with Exelon Corp. last fall to operate the nuclear plant.
Lochbaum said OPPD will have to fix the structural problem and convince the commission that there are no other surprises lingering at Fort Calhoun. He thinks that's possible.
"So far it looks like they're still on the path to restart," Lochbaum said.
Utility officials said part of why they believe it's worth repairing Fort Calhoun is that the cost of nuclear fuel is stable in comparison to coal and natural gas, and that it produces no greenhouse gases.
"It's a reliable source of electricity that's carbon-free. That becomes more valuable going forward," OPPD spokesman Jeff Hanson said.
But it will be difficult to convince some that Fort Calhoun is safe and a good investment.
The Sierra Club of Iowa has asked the commission to revoke Fort Calhoun's operating license because of its history of safety violations. Mike Ryan, with the environmental group Clean Nebraska, said he would rather see the nuclear plant closed.
"The attitude of the NRC is always making sure it's safe before restart. What if you can't make it safe?" he said.
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NRC page on Fort Calhoun: http://1.usa.gov/GBq2TF
Omaha Public Power District: http://www.oppd.com