Nuke plants use dry casks for spent fuel

Bakersfield Californian ^ | 3/28/05 | Erica Werner - AP

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WASHINGTON (AP) - About 40 percent of the nation's nuclear power plants have begun moving spent fuel out of cooling pools and into massive dry casks, embracing a storage approach that a National Academy of Sciences panel said offers safety advantages.

The nation's 64 active nuclear power plants, which together house 103 reactors, all now store nuclear waste in pools of water after it is removed from reactors. Eventually, the spent fuel is supposed to be shipped to a national nuclear waste dump planned for Yucca Mountain in Nevada.

As Yucca Mountain has been delayed, utilities are increasingly moving some of the waste from pools to huge metal or metal-and-concrete casks. That method is now employed at about 25 active U.S. nuclear power plants, according to the Nuclear Energy Institute, the industry trade group.

NEI spokesman Steve Kerekes said Monday that both storage methods are safe - contrary to the findings of the National Academy of Sciences panel, which told the Nuclear Regulatory Commission that the vulnerability of spent nuclear fuel pools to terrorist attacks needs urgent new study.

The Academy panel also said that in some cases, the NRC might find it prudent to move spent fuel from cooling pools to dry cask storage more quickly.

Agreeing with industry, the NRC said either form of storage "provides reasonable assurance that public health and safety, the environment and the common defense and security will be adequately protected."

The NRC also said the additional analyses recommended by the Academy panel, including studies of possible attacks by large aircraft or explosives, were "more than is needed."

Watchdog groups contend the casks are safer than the pools, especially when the pools reach capacity. But the dry casks are more expensive - a cost that would be born by the power plant owners and the government, which is being sued by utilities for failing to make good on a promise to accept their nuclear waste starting in 1998.

The report by a 13-member National Academy panel of nuclear scientists and power plant experts was delivered to the NRC last summer. It remains classified but portions were released to lawmakers this month as part of a report Congress requested from the NRC.

The Academy's executive officer, E. William Colglazier, criticized the NRC report and an accompanying letter by commission Chairman Nils Diaz as misleading and incomplete. Colglazier also said the NRC was delaying attempts by the Academy to release a declassified, public version of the panel's study as required by law.

"In our feeling it all could have been avoided if the Nuclear Regulatory Commission had approved a release of a public version of our report in a more timely manner," Colglazier said Monday.

NRC spokeswoman Sue Gagner said the agency was working with the Academy on releasing a public report that doesn't contain information of use to terrorists. She wouldn't comment on Colglazier's criticism of the NRC letter and report beyond saying, "Our letter made the points as we see them."

Rep. Ed Markey, D-Mass., accused the NRC of trying to withhold information from the public by failing to approve a declassified report, and asked the agency's inspector general to investigate the issue.

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On the Net:

National Academy of Sciences: http://www4.nationalacademies.org/nas/nashome.nsf

Nuclear Regulatory Commission: http://www.nrc.gov/

Nuclear Energy Institute: http://www.nei.org/

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Dry Cask Storage

http://www.nrc.gov/waste/spent-fuel-storage/dry-cask-storage.html

In the late 1970s and early 1980s, the need for alternative storage began to grow when pools at many nuclear reactors began to fill up with stored spent fuel. Utilities began looking at options such as dry cask storage for increasing spent fuel storage capacity. See the graph of nuclear fuel storage pool capacity.

Dry cask storage allows spent fuel that has already been cooled in the spent fuel pool for at least one year to be surrounded by inert gas inside a container called a cask. The casks are typically steel cylinders that are either welded or bolted closed. The steel cylinder provides a leak-tight containment of the spent fuel. Each cylinder is surrounded by additional steel, concrete, or other material to provide radiation shielding to workers and members of the public. Some of the cask designs can be used for both storage and transportation.

There are various dry storage cask system designs. With some designs, the steel cylinders containing the fuel are placed vertically in a concrete vault; other designs orient the cylinders horizontally. The concrete vaults provide the radiation shielding. Other cask designs orient the steel cylinder vertically on a concrete pad at a dry cask storage site and use both metal and concrete outer cylinders for radiation shielding. See the picture of a typical dry cask storage system.

The first dry storage installation was licensed by the NRC in 1986 at the Surry Nuclear Power Plant in Virginia.

Spent fuel is currently stored in dry cask systems at a growing number of power plant sites, and at an interim facility located at the Idaho National Environmental and Engineering Laboratory near Idaho Falls, Idaho. See the map showing the location of existing independent spent fuel storage installations.

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