Used Nuclear Fuel Storage

Columbia's Independent Used Fuel Storage Installaion

Storage of Used Nuclear Fuel

Used nuclear fuel taken from the Columbia Generating Station reactor is a solid dry material safely stored in a secure Independent Spent Fuel Storage Installation, or ISFSI.

Columbia began operations in 1984. Until 2002, all of the used fuel from the reactor was stored in a specially designed, temperature-controlled water-filled fuel pool in the reactor building. The pool, able to accommodate 2,658 fuel assemblies, was designed as a short-term storage option until a national repository could be built. The repository, later identified as Yucca Mountain in Nevada, remains incomplete. Meanwhile used fuel is safely stored on-site at nuclear power plants across the county. 

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Planning for Energy Northwest’s dry cask storage project, or ISFSI, began in the late 1990s. Construction followed in 2001 and loading and storage of the first five casks was completed in April 2002. Additional building campaigns were successfully completed in 2004 and 2008, bringing the total number of casks loaded to 27. During 2014 Energy Northwest loaded and moved additional casks to on-site storage, bringing the total number of on-site casks to 36. Three new pads will be poured during 2016 for future cask storage. In 2018, nine more casks were added to bring the total number to 45.

Each concrete and steel storage cylinder stands about 19 feet tall and measures 11 feet in diameter. The outer concrete cask encases a stainless steel canister. Heat is transferred from the fuel to the walls of the helium-filled canister. Space between the canister and cask allows air flow to cool the used fuel and canister. The casks rest on a large, two-foot-thick reinforced concrete pad in a fenced secure area adjacent to the plant.   


Integrated Used Fuel Management

Under the integrated management approach, used nuclear fuel is stored on site at plants in steel-lined water-filled concrete pools, and above ground in massive airtight steel or concrete-and-steel dry canisters. The dry storage system allows for the safe and efficient storage of Columbia Generating Station’s used fuel until such time as it can be transported to a national repository. This solution will allow Columbia to continue to provide inexpensive power for ratepayers of the Northwest for many years to come. Although the Nuclear Regulatory Commission determined used fuel could remain in safe storage at plant sites for 100 years, such storage was never intended to be permanent.  

Repository Development

In 1983, Energy Northwest and other U.S. nuclear utilities entered into an agreement with the Department of Energy for disposal of used nuclear fuel beginning on or before January 1998. The agreement was established under the Nuclear Waste Policy Acts of 1982, and required Energy Northwest and other nuclear operators to pay DOE an annual fee. 

A used nuclear fuel storage cask is transported to the ISFSI. Easch cask weighs about 185 tons. The crawler, which moves at 0.3 mph, is affectionately known as "greased lightning."

The fees, paid to the Nuclear Waste Fund, equal one-tenth of a cent for every nuclear-generated kilowatt-hour of electricity produced, amounting to many billions of dollars. Energy Northwest alone has paid more than $100 million in fees since 1983. The goal of a national repository remains far from completion. 

In 2002, Congress approved Yucca Mountain, Nev., a remote desert location, as the site for a centralized deep geologic repository for used nuclear fuel and other high-level radioactive waste. The DOE planned to apply for a Nuclear Regulatory Commission license for the Yucca Mountain by the end of 2004. DOE has subsequently notified Energy Northwest and other nuclear utilities of an indefinite delay in fulfilling their contractual obligations to provide safe methods of long-term storage for used fuel.