Recent events have renewed long-standing congressional interest in safe management of spent nuclear fuel (SNF) and other high-level nuclear waste. These issues have been examined and debated for decades, sometimes renewed by world events like the 9/11 terrorist attacks. The incident at the Fukushima Dai-ichi nuclear reactor complex in Japan, combined with the termination of the Yucca Mountain geologic repository project, have contributed to the increased interest. This report focuses on the current situation with spent nuclear fuel storage in the United States. It does not address all of the issues associated with permanent disposal of SNF, but rather focuses on the SNF storage situation, primarily at current and former reactor facilities and former reactor sites for the potentially foreseeable future (i.e., a total of 300 years). Although no nation has yet established a permanent disposal repository for SNF and other forms of high-level radioactive waste (HLW), there is broad consensus that a geological repository is the preferred method for these wastes. In the United States, the disposal repository location has been debated for decades. The proposed repository in Nevada at Yucca Mountain was terminated in 2009, although the project continues to be debated and litigated. Whether the current situation with the Yucca Mountain project is merely a temporary hiatus or becomes a permanent shutdown, extended storage for longer than previously anticipated is virtually assured. There is also no clear consensus on interim storage of SNF. The SNF storage issues most widely debated include What strategies should be employed for SNF storage, pending disposal; Where should SNF be stored on an interim basis; and What SNF management structure should be used? A focus of this renewed broader debate is the recently completed report by the Blue Ribbon Commission on America's Nuclear Future (BRC), which released its final report on January 29, 2012. This final report modified a July 2011 draft, which followed nearly more than a year of effort, including extensive public testimony and several subcommittee reports after the Commission was chartered by the Secretary of Energy in early 2010. Some, including the U.S. Nuclear Regulatory Commission (NRC), view the current situation as providing adequate safety. Others, including the National Academy of Sciences, have observed that safety may be improved by wider use of dry storage methods. Some analysts, including the BRC, have considered issues beyond safety—including cost and impact on investments—and urge construction of an interim centralized storage at a "volunteer" location after sufficient cooling has occurred. Some have recommended a more limited approach to consolidation of interim SNF storage using a smaller number of existing operational reactor sites, away from the original generating reactor, for SNF located where there is no operating reactor generating additional SNF or if repository delays result in greater stranded SNF and higher financial liabilities. The two primary technologies being employed in the United States are wet pool storage and dry cask storage (see " How Is Spent Fuel Stored Now? "). Senator Dianne Feinstein, chair of the Senate Subcommittee on Energy and Water Development Appropriations, with jurisdiction over NRC and the U.S. Department of Energy (DOE), stated at a hearing in March 2011: Most significantly, I believe we must rethink how we manage spent fuel. Spent fuel must remain in pools for at least five to seven years, at which time it can be moved to safer dry cask storage. However, these pools often become de facto long-term storage, with fuel assemblies "re-racked" thus increasing the heat load of the pools. In California, for instance, fuel removed from reactors in 1984 is still cooling in wet spent fuel pools.... Reports out of Japan indicate there were no problems with the dry casks at Dai-ichi. To me, that suggests we should at least consider a policy that would encourage quicker movement of spent fuel to dry cask storage. Senator Feinstein followed up this hearing statement with a formal letter to the NRC chairman asking NRC "to seriously consider regulatory policies that would encourage the movement of nuclear fuel, once sufficiently cool, out of spent fuel pools and into dry cask storage systems." Citing the 2006 study by the National Academy of Sciences (NAS) National Research Council ( Safety and Security of Commercial Spent Nuclear Fuel Storage ), Senator Feinstein specifically asked the "NRC to initiate a rulemaking process to immediately require a more rapid shift of spent fuel to dry casks." Senator Feinstein indicated her concern about spent fuel management in evaluating proposals for funding small modular reactors. NRC subsequently considered SNF storage needs a part of its Near-Term Task Force on the Fukushima Dai-ichi incident. A House Appropriations Subcommittee report recently expressed concern about current spent fuel storage, indicating that "[c]onsolidation of this material in a single site that provides enhanced safety and security will improve public comfort with nuclear power, reduce potential safety and security risk, and fulfill the federal government's obligation under the Nuclear Waste Policy Act of 1982 to assume responsibility of spent fuel." Although consolidated interim storage of SNF has received widespread support as a general concept for many years, proposals for SNF storage at specific locations have been vigorously opposed. The issue of SNF storage is inextricably linked to related longer-term issues like nuclear power plant operations and construction, SNF reprocessing, and establishment of a permanent repository. This report is focused on SNF storage, and does not provide a detailed examination of these related issues. Worldwide, there are 436 operational nuclear power reactors in 32 countries and 122 permanently shut-down nuclear power reactors, including several in countries where SNF continues to be stored after the reactor fleet has been shut down. No country, including the United States, has yet established an operating permanent disposal site for SNF or other forms of high-level nuclear waste. All nations rely—to varying degrees—on long-term SNF storage. Although the United States has not fully addressed its nuclear waste issues, DOE has, since 1999, operated a permanent geological repository for plutonium-contaminated transuranic (i.e., mainly plutonium-contaminated) waste from nuclear weapons operations in New Mexico. Known as the Waste Isolation Pilot Plant (WIPP), this waste disposal repository was constructed and began operations following decades of detailed technical and institutional planning, active state and community involvement, and compliance work to meet various federal and state environmental review and permitting requirements. The WIPP site is explicitly prohibited by law from receiving SNF or high-level waste, but is widely regarded as a model for other waste facility—both disposal and storage—siting efforts. A recent survey of spent fuel storage in the 10 countries with significant nuclear operations found that all countries store substantial amounts of SNF in pools or dry cask facilities, regardless of their policy on reprocessing. Although much of the congressional attention has focused on the issues of the permanent geological repository proposed for Yucca Mountain in Nevada, there are a number of reasons to also consider SNF storage issues. First, under any scenario for waste acceptance into a permanent repository or an interim consolidated storage site, long-term storage of SNF will be required for a considerable time. Notwithstanding the mandate in the Nuclear Waste Policy Act (NWPA) and various contracts that DOE begin accepting SNF for disposal in 1998, no disposal repository has been completed or licensed. The 2009 termination of the Yucca Mountain disposal project continues the ongoing delay in opening a permanent geologic repository. Hence, the disposal delay prolongs storage needs. Even if a disposal repository were to begin operation quickly, the time required to ship SNF would require an extended period of storage. In its most recent estimate, prior to termination of the Yucca Mountain repository program, DOE projected that, if waste acceptance were to begin in 2020, there would be a need for commercial interim storage until at least 2056, given this projected shipment rate and the continued generation of new SNF. Also, current law—the NWPA—sets a limit on how much waste can be put in the first repository, and the U.S. inventory of SNF and other high-level waste requiring disposal has already exceeded this limit. The NWPA "prohibit[s] the emplacement in the first repository of a quantity of spent fuel containing in excess of 70,000 metric tons of uranium (MTU) or a quantity of solidified high-level radioactive waste resulting from the reprocessing of such a quantity of spent fuel until such time as a second repository is in operation." Of this 70,000 MTU limit set by Congress on the first repository in the NWPA, approximately 90% (63,000 MTU) of the capacity is allocated to commercial spent nuclear fuel and high-level radioactive waste from reprocessing. The remaining 10% capacity would be used for about 2,455 MTU of DOE spent nuclear fuel (including naval spent nuclear fuel) and the equivalent of 4,667 MTU of DOE high-level radioactive waste. Hence, the current quantity of SNF (i.e., 67,450 MTU of civilian SNF and 2,458 MTU of DOE-owned SNF) and high-level waste being stored would fill the proposed Yucca Mountain repository beyond the limit imposed by Congress in the NWPA, necessitating a need to build a second repository or change the legal limit. DOE has evaluated the capacity of the proposed Yucca Mountain repository and concluded that Yucca Mountain could hold more than the legal limit of 70,000 MTU and "has the physical capability to allow disposal of a much larger inventory." If waste were accepted at a consolidated nuclear waste storage site, rather than a disposal repository, the need for interim storage technologies could continue for a longer period. Hence, the issues related to safe long-term SNF storage—regardless of the current debate about a permanent geologic repository—warrant consideration.