Used Fuel Storage

Responsible Nuclear Waste Disposal:
An Unmet Obligation
 by the CY, YAEC and New England Council

What is Dry Fuel Storage
Why is CY Switching From Wet to Dry Fuel Storage?

What is Dry Fuel Storage?

Most electric generating plants use some type of fuel to heat water and transform it to steam, which turns turbines that drive a generator to produce electricity. Nuclear power plants use small solid ceramic pellets made of slightly enriched uranium held inside metal rods that are bundled together in what is called a fuel assembly. These fuel assemblies can be used for several years before they must be replaced. Once they have been spent (or used) they must be shielded because they are highly radioactive.

Used radioactive nuclear fuel can be safely shielded with water, or steel and concrete. The U.S. Nuclear Regulatory Commission (NRC) allows two types of storage methods for used nuclear fuel using these shielding methods. Wet storage involves placing the fuel assemblies in a large, deep pool filled with water inside a building on the plant site. Although similar in size to a large swimming pool, these pools are specially designed with 6-foot-thick concrete walls, steel liners and mechanical equipment to cool the fuel, which gives off heat as well as radiation.
Dry storage involves placing the fuel inside airtight stainless steel canisters, which are placed inside large steel-lined concrete containers and stored on a concrete pad. Dry storage is a passive system with no moving parts. The fuel is kept cool by air entering vents on the side of the container and circulating around the outside of the steel canister. Both wet and dry storage methods are safe, have stringent security requirements, and meet rigorous safety requirements to withstand severe incidents, such as earthquakes, tornadoes and floods.
CY currently stores 1,019 used fuel assemblies in a pool inside a building on the plant site. Each assembly in the pool is about 11.5 feet long and weighs about 1300 pounds. The dry storage system we've chosen for this fuel was designed by NAC International and is similar to the dry storage systems planned for the Yankee Rowe plant in Massachusetts and the Maine Yankee plant in Maine. This storage system, which is licensed by the Nuclear Regulatory Commission, is a dual-purpose system that not only safely stores the fuel, but also prepares it for transport. The stainless steel canisters that hold the fuel inside the concrete storage containers are designed to be removed from the concrete structures and placed inside transport casks. This will significantly reduce the number of fuel shipments from the CY site when the Department of Energy (DOE) begins removing the fuel.
There will be 43 fuel storage containers placed on a 100 by 200-foot, three-foot-thick concrete pad. Each concrete container has a three and a half-inch steel liner surrounded by 21 inches of reinforced concrete. Each storage container, when loaded with the fuel canister and fuel, will weigh 126 tons. The entire dry storage process -- procuring materials, fabricating the fuel containers, constructing the storage facility, and transferring the fuel -- will take approximately two to three years to complete. Three of the 43 storage containers will store sections of the reactor vessel internals that are too radioactive to ship to a low-level radioactive waste disposal facility. The DOE also plans to remove this material.

The location for CY's dry storage facility was chosen after several months of thoroughly examining eight potential locations on CY's 525-acre site. Of the eight locations, the most suitable site, which is the site we have chosen, is a 2-acre parcel of land about 3/4 of a mile from the plant. It is naturally hidden from the Connecticut and Salmon rivers, is more than 45 feet above the flood plain, and will have the least impact on wetlands from construction.

Why is CY Switching From Wet to Dry Fuel Storage?

We must continue to store used fuel at CY because the Department of Energy (DOE) has failed to meet its legal obligation to remove the fuel to a permanent repository. Although the DOE is in the process of developing a repository in the Nevada desert, they now say it may take two or more decades before they will complete fuel removal at CY. Despite signing a contract to begin removing fuel in January 1998, the DOE has defaulted on their contractual obligation and has not offered any alternative other than continued storage at the CY site.
The DOE has thrust the responsibility of continued storage onto Connecticut Yankee, the cost of continued storage onto electric consumers, and the uncertainty of continued storage and reuse of the CY site onto the region. The only option we do have is the method of storage.

CY is required by the NRC to safely store the fuel until the DOE accepts it and to safely decommission the plant. For CY, transferring the fuel from wet to dry storage will allow us to complete decommissioning and restoration of the original plant site. The Spent Fuel Pool building could not be decommissioned if it was being used to store fuel. In addition, removing the fuel to a location that is not right in the middle of the plant industrial area will facilitate dismantling the buildings and enable CY to verify the site is available for reuse.

Although dry storage is as safe as pool storage, it is less complex and less expensive to operate because there are no moving parts to monitor and maintain. For electric consumers in Connecticut and New England, this is significant because they, not the DOE, are currently paying for continued fuel storage at CY as a result of DOE delays. In order to minimize the impact on electric consumers, the Connecticut Department of Public Utility Control (DPUC), the Office of Consumer Counsel (OCC) and CY, agreed in a settlement on decommissioning costs, that the fuel be stored in a dry storage system. The Federal Energy Regulatory Commission recently approved that settlement. Because electric consumers fund decommissioning and fuel storage, CY is obligated to spend those funds prudently, and under the supervision of federal regulators.

Now that the CY plant is permanently shut down and no longer produces power, its value has significantly decreased affecting tax revenues to the town of Haddam. Completing decommissioning and restoring the site in a timely manner would make the CY site available for alternative use sooner and increase the potential for new tax revenue for the town. Keeping the fuel in the pool in the middle of the CY plant industrial area would prevent CY from completing the decommissioning and complicate reuse of the site, including a gas-fired electric generating plant currently under consideration. Transferring the fuel to a dry storage facility outside the plant industrial area will provide greater assurance of potential reuse.

In addition to being able to complete decommissioning, to agreeing with state and federal regulators to use dry storage, and to enhancing the potential for reuse, a dry storage system also has inherent advantages. For example, dry storage is passive and requires less maintenance because there are no moving or mechanical parts, the dual purpose dry storage system CY has chosen packages and prepares the fuel for transport, and the system reduces the number of fuel shipments from CY from several hundred to 43 when the DOE begins removing fuel.
Numerous other commercial nuclear plants, both operating and shutdown, currently use, or are preparing to use dry storage for their used fuel. In light of a recent settlement between the DOE and PECO Energy Company regarding funding for future fuel storage at one of the company's operating nuclear plants, many more plants will probably be turning to dry storage as the preferred option. In the settlement, the DOE stipulated that the used fuel must be stored in a dry storage facility.

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