Duke Energy's shuttered Crystal River nuclear plant will cost $1.18 billion in today's dollars to decommission over the next 60 years, the utility announced Tuesday.

Duke expects the current decommissioning fund, along with the interest the fund will earn in the coming decades, and the plant's other owners to cover the cost.

The decommissioning fund, which Duke's customers paid into as part of their monthly bills over the years, currently stands at about $780 million. The money is used to manage spent fuel stored at the site, dismantle the plant and clean up any contamination.

"We're certainly encouraged by the fact that Duke believes it will not have to seek any other money from ratepayers," said J.R. Kelly, the state public counsel who represents consumers before the Public Service Commission.

But Kelly warned not to assume there won't be any additional cost.

"You won't really know until you progress over the years through decommissioning," he said.

One cost not considered part of decommissioning: building permanent fuel storage units at the site. That will cost at least $94 million, a bill that Duke's 1.7 million Florida customers might have to pay.

Duke filed details of its decommissioning plan with the U.S. Nuclear Regulatory Commission on Tuesday, including cost and the method it would use, called safe storage (known in the industry as SAFSTOR).

In SAFSTOR, a nuclear facility is left intact or may be partially dismantled to decontaminate the facility over time.

"Decommissioning the Crystal River nuclear plant will be a well-defined process, with significant NRC oversight," said Duke Energy Crystal River decommissioning director Terry Hobbs. "Nuclear safety will remain Duke Energy's top priority. The plant will remain in a safe, stable condition, and our comprehensive emergency plan and 24/7 security force will remain in place."

Putting the plant in safe storage will save millions in up-front costs while letting natural decay do most of the decontamination, said Duke, which owns almost 92 percent of the plant; municipal utilities own the rest.

Only a handful of plants around the country are in safe storage, including the infamous Three Mile Island reactor near Middletown, Pa., where a 1979 meltdown became one of the worst nuclear disasters in American history. So is the N.S. Savannah, the world's first nuclear cargo-passenger ship and a showcase of President Dwight Eisenhower's "Atoms for Peace" initiative, now docked outside a Baltimore pier.

U.S. nuclear plants store used fuel on site — either in pools or dry casks — because the country does not have a central repository.

The spent fuel at the Crystal River plant will remain in an existing on-site pool until Duke completes construction of the dry cask storage in 2016. All used fuel will be transferred from the pool into dry storage by 2019. Duke's plan calls for the spent fuel to be transferred to the Department of Energy in 2036, by which time a more permanent storage solution is presumably in place. The empty dry cask storage facility will be dismantled with other buildings in 2072.

Radiological and environmental monitoring will continue during the entire process.

In February, Duke announced the closing of the Crystal River nuclear plant after a failed do-it-yourself maintenance and upgrade project in 2009. As workers cut into the 42-inch thick concrete containment building that houses the reactor, the building cracked. An attempt to repair the crack and bring the plant back online led to more cracks.

Estimates to repair the building reached as high as $3.4 billion. Duke decided to shut down the plant rather than fix it and risk another failure.

But even closing the plant is costing customers a bundle. They are paying $1.7 billion for the attempted upgrade plus as much as $300 million a year to purchase electricity to replace what the nuclear plant would have produced.

Add to that at least $1.5 billion to build a new natural gas plant that Duke intends to construct in part to replace the nuclear plant.

Roger Hannah, a spokesman for the Nuclear Regulatory Commission, said the agency will review Duke's plan to determine if it meets federal laws and standards for decommissioning a nuclear plant. A public comment period will be held within a few months, he said.

If the NRC determines Duke's plan is insufficient, Hannah said, it could raise the cost of decommissioning and lead to more than the $1.18 billion Duke currently estimates.

"Nuclear is neither safe, clean or cheap," said Susan Glickman, of the Southern Alliance for Clean Energy. "Nuclear power is expensive, even at the end of its life. And we all pay for it in the end."

Ivan Penn can be reached at ipenn@tampabay.com or (727) 892-2332.