Energy Northwest will begin moving more used nuclear fuel to dry storage Monday.
It's the fourth campaign to remove used fuel from the storage pool next to the reactor core of the Columbia Generating Station and put it in dry storage near the nuclear power reactor, said Energy Northwest spokesman John Dobken.
The proposed Yucca Mountain, Nev., nuclear repository was expected to take used commercial fuel. But when it failed to open as planned in 1998, Energy Northwest began building a secure, outdoor storage pad for the fuel in 2001.
Previously, all of the plant's used fuel had been kept in the storage pool, which can hold about 2,650 fuel assemblies. Every two years the reactor is shut down so about a third of the fuel assemblies in the reactor core can be removed and replaced with fresh fuel.
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Energy Northwest has nine canisters ready that can each hold 68 fuel assemblies. The canisters will be lifted up to the used fuel storage pool and placed in the water to be filled with fuel assemblies that are about 14 feet long. The assemblies are kept under 23 feet of water.
Each of the canisters will be capped with a lid weighing about 10,000 pounds and then welded shut. The stainless steel canisters will be placed in a concrete cask for a final package that weighs about 185 tons and stands 19 feet tall.
In 2002 five casks were filled, and campaigns in 2004 and 2008 brought the number of casks in dry storage to 27.
Some of the assemblies that will be removed now have been in the storage pool since the 1980s, Dobken said. Energy Northwest expects to complete the work about May 10.
The dry storage is temporary until the nation has either an interim or final waste repository for used commercial reactor fuel. But each cask can safely store used nuclear fuel for hundreds of years, according to Energy Northwest. Crews periodically inspect the casks and the concrete pads they sit on to ensure the integrity of the casks and the continued strength of the storage pad.
Columbia Generating Station produces approximately 1,170 megawatts of electricity, equivalent to about 10 percent of Washington's power and 4 percent of all the electric power used in the Pacific Northwest.
-- Annette Cary: 582-1533; firstname.lastname@example.org; Twitter: @HanfordNews