Nuclear waste is long-lived and very hazardous—without protective shielding, the intense radioactivity of the waste can kill a person within minutes or cause cancer months or even decades after exposure. Thus, careful management is required to isolate it from humans and the environment. To accomplish this, the National Academy of Sciences first endorsed the concept of nuclear waste disposal in deep geologic formations in a 1957 report to the U.S. Atomic Energy Commission, which has since been articulated by experts as the safest and most secure method of permanent disposal. However, progress toward developing a geologic repository was slow until NWPA was enacted in 1983. Citing the potential risks of the accumulating amounts of nuclear waste, NWPA required the federal government to take responsibility for the disposition of nuclear waste and required DOE to develop a permanent geologic repository to protect public health and safety and the environment for current and future generations. Specifically, the act required DOE to study several locations around the country for possible repository sites and develop a contractual relationship with industry for disposal of the nuclear waste. The Congress amended NWPA in 1987 to restrict scientific study and characterization of a possible repository to only Yucca Mountain. (Fig. 2 shows the north crest of Yucca Mountain and a cut-out of the proposed mined repository.) After the Congress approved Yucca Mountain as a suitable site for the development of a permanent nuclear waste repository in 2002, DOE began preparing a license application for submittal to NRC, which has regulatory authority over commercial nuclear waste management facilities. DOE submitted its license application to NRC in June 2008, and NRC accepted the license application for review in September 2008. NWPA requires NRC to complete its review of DOE’s license application for the Yucca Mountain repository in 3 years, although a fourth year is allowed if NRC deems it necessary and complies with certain reporting requirements. To pay the nuclear power industry’s share of the cost for the Yucca Mountain repository, NWPA established the Nuclear Waste Fund, which is funded by a fee of one mill (one-tenth of a cent) per kilowatt-hour of nuclear-generated electricity that the federal government collects from electric power companies. DOE reported that, at the end of fiscal year 2008, the Nuclear Waste Fund contained $22 billion, with an additional $1.9 billion projected to be added in 2009. DOE receives money from the Nuclear Waste Fund through congressional appropriations. Additional funding for the repository comes from an appropriation which provides for the disposal cost of DOE-managed spent nuclear fuel and high-level waste. NWPA caps nuclear waste that can be disposed of at the Yucca Mountain repository at 70,000 metric tons until a second repository is available. However, the nation has already accumulated about 70,000 metric tons of nuclear waste at current reactor sites and DOE facilities. Without a change in the law to raise the cap or to allow the construction of a second repository, DOE can dispose of only the current nuclear waste inventory. The nation will have to develop a strategy for an additional 83,000 metric tons of waste expected to be generated if NRC issues 20-year license extensions to all of the currently operating nuclear reactors. This amount does not include any nuclear waste generated by new reactors or future defense activities, or greater than class C nuclear waste. According to DOE and industry studies, three to four times the 70,000 metric tons—and possibly more—could potentially be disposed safely in Yucca Mountain, which could address current and some future waste inventories, potentially delaying the need for a second repository for several generations. Nuclear waste has continued to accumulate at the nation’s commercial and DOE nuclear facilities over the past 60 years. Facility managers must actively manage the nuclear waste by continually isolating, confining, and monitoring it to keep humans and the environment safe. Most spent nuclear fuel is stored at reactor sites, immersed in pools of water designed to cool and isolate it from the environment. With nowhere to dispose of the spent nuclear fuel, the racks holding spent fuel in the pools have been rearranged to allow for more dense storage of assemblies. Even with this re-racking, spent nuclear fuel pools are reaching their capacities. Some critics have expressed concern about the remote possibility of an overcrowded spent nuclear fuel pool releasing large amounts of radiation if an accident or other event caused the pool to lose water, potentially leading to a fire that could disperse radioactive material. As reactor operators have run out of space in their spent nuclear fuel pools, they have turned in increasing number to dry cask storage systems that generally consist of stainless steel canisters placed inside larger stainless steel or concrete casks. (See fig. 3.) NRC requires protective shielding, routine inspections and monitoring, and security systems to isolate the nuclear waste to protect humans and the environment. NRC has determined that these dry cask storage systems can safely store nuclear waste, but NRC considers them to be interim measures. In 1990, NRC issued a revised waste confidence rule, stating that it had co that the waste generated by a reactor can be safely stored in either wet or dry storage for 30 years beyond a reactor’s life, including license extensions. NRC further determined that it had reasonable assurance thate safe geologic disposal was feasible and that a geologic repository would b operational by about 2025. More recently, NRC has published a notice of proposed rulemaking to revise that rule, proposing that waste generated by a reactor can be safely stored for 60 years beyond the life of a reac tor and that geologic disposal would be available in 50 to 60 years beyond a NRC is currently considering whether to republish its reactor’s life. proposed rule to seek additional public input on certain issues. Forty-fi reactor sites or former reactor sites in 30 states have dry storage faci for their spent nuclear fuel a sites storing spent nuclear fuel is likely to continue to grow until an alternative is implemented. s of June 2009, and the number of reactor Implementing a permanent, safe, and secure disposal solution for the nuclear waste is of concern to the nation, particularly state governmentsand local communities, because many of the 80 sites where nuclear wast e is currently stored are near large populations or major water sources or consist of shutdown reactor sites that tie up land that could be used for other purposes. In addition, states that have DOE facilities with nuclear waste storage are concerned because of possible contamination to aquifers, rivers, and other natural resources. DOE’s Hanford Reservation, located near Richland, Washington, was a major component of the nation nuclear weapons defense program from 1943 until 1989, when operat ions ceased. In the settlement of a lawsuit filed by the state of Washin 2003, DOE agreed not to ship certain nuclear waste to Hanford until environmental reviews were complete. In August 2009, the U.S. government stated that the preferred alternative in DOE’s environmen review would include limitations on certain nuclear waste shipments to Hanford until the process of immobilizing tank waste in glass begins, tal expected in 2019. Moreover, some commercial and DOE sites where the nuclear waste is stored may not be able to accommodate much additional waste safely because of limited storage space or community objections. These sites will require a more immediate solution. The nation has considered proposals to build centralized storage facilities where waste from reactor sites could be consolidated. The 1987 amendment to NWPA established the Office of the Nuclear Waste Negotiator to try to broker an agreement for a community to host a repository or interim storage facility. Two negotiators worked with local communities and Native American tribes for several years, but neither was able to conclude a proposed agreement with a willing community by January 1995, when the office’s authority expired. Subsequently, in 2006 after a 9-year licensing process, a consortium of electric power companies called Private Fuel Storage obtained a NRC license for a private centralized storage facility on the reservation of the Skull Valley Band of the Goshute Indians in Utah. NRC’s 20-year license—with an option for an additional 20 years—allows storage of up to 40,000 metric tons of commercial spent nuclear fuel. However, construction of the Private Fuel Storage facility has been delayed by Department of the Interior decisions not to approve the lease of tribal lands to Private Fuel Storage and declining to issue the necessary rights-of-way to transport nuclear waste to the facility through Bureau of Land Management land. Private Fuel Storage and the Skull Valley Band of Goshutes filed a federal lawsuit in 2007 to overturn Interior’s decisions. Reprocessing nuclear waste could potentially reduce, but not eliminate, the amount of waste for disposal. In reprocessing, usable uranium and plutonium are recovered from spent nuclear fuel and are used to make new fuel rods. However, current reprocessing technologies separate weapons usable plutonium and other fissionable materials from the spent nuclear fuel, raising concerns about nuclear proliferation by terrorists or enemy states. Although the United States pioneered the reprocessing technologies used by other countries, such as France and Russia, presidents Gerald Ford and Jimmy Carter ended government support for commercial reprocessing in the United States in 1976 and 1977, respectively, primarily due to proliferation concerns. Although President Ronald Reagan lifted the ban on government support in 1981, the nation has not embarked on any reprocessing program due to proliferation and cost concerns—the Congressional Budget Office recently reported that current reprocessing technologies are more expensive than direct disposal of the waste in a geologic repository. DOE’s Fuel Cycle Research and Development program is currently performing research in reprocessing technologies that would not separate out weapons usable plutonium, but it is not certain whether these technologies will become cost-effective. The general consensus of the international scientific community is that geologic disposal is the preferred long-term nuclear waste management alternative.