Safe Interim On-Site Storage of Used Nuclear Fuel Nuclear plant used fuel storage capacity. Nuclear plants were designed to store at least a decade’s worth of used fuel. The federal government was to begin moving used fuel from plant sites to a centralized storage facility in 1998, as mandated by the Nuclear Waste Policy Act of 1982. This delay means that nuclear plants must store more used fuel than expected and longer than originally intended. By 2010, the earliest opening date for a repository, 78 plants will have no room left in their used fuel pools. Used fuel pools: safe storage inside plants. At most plants, used fuel is stored in steel-lined, concrete vaults filled with water. In these used fuel pools, the water acts as a natural barrier for radiation from the fuel assemblies. The water also keeps the fuel cool while the fuel decays—becomes less radioactive. The water itself never leaves the inside of the plant’s concrete building. Dry storage facilities: safe storage outside plants. Since 1986, more than a dozen U.S. plants, including several shutdown units, have supplemented their storage capacity by building above-ground, dry storage facilities. By mid-1999, nearly 150 of these containers were being used in the United States. Other countries also have safely and successfully stored used fuel above ground since the mid-1970s. Dry storage container construction. Containers are made of steel or steel-reinforced concrete, 18 or more inches thick, as well as lead, which serve as proven, effective radiation shields. Once loaded with used fuel assemblies, the containers are stored horizontally in a concrete vault, or they stand upright on a three-foot-thick concrete pad. The containers are designed and tested to prevent the release of radioactivity under the most extreme conditions—earthquakes, tornadoes, hurricanes, floods and sabotage—and are naturally cooled and ventilated. NRC design approval and licensing of dry storage containers. Each container design must be approved by the U.S. Nuclear Regulatory Commission. While the NRC had determined that used fuel can be safely stored at plants sites for at least 30 years beyond the licensed operating life of the plant, the agency requires that dry storage containers be constantly monitored and relicensed every 20 years. Dry storage systems are only a temporary solution. Dry storage containers are expensive, ranging from $500,000 for a container stored in a vault to more than $1 million for a container stored outside on a concrete pad. Will public utility commissions allow utilities to recover the cost of this extra storage system from customers when the customers already have contributed billions of dollars into the federally mandated Nuclear Waste Fund? Also, state and local officials are concerned that, unless the U.S. Department of Energy fulfills its legal obligation to provide used fuel disposal, on-site dry storage facilities will become, in effect, repositories themselves. Certain states have moved to limit the development or expansion of these facilities or to place conditions on the utilities in exchange for approval.