	Introduction

Recent events have renewed long-standing congressional interest in safe management of spent nuclear fuel (SNF) and other high-level nuclear waste. 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 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. The 2009 termination of the Yucca Mountain disposal project continues the ongoing delay in opening a permanent geologic repository. 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. The recent report by the BRC also implicated the current "impasse" in the U.S. nuclear waste program as a hindrance to expansion of nuclear power, among other impacts:
Put simply, this nation's failure to come to grips with the nuclear waste issue has already proved damaging and costly and it will be more damaging and more costly the longer it continues: damaging to prospects for maintaining a potentially important energy supply option for the future, damaging to state-federal relations and public confidence in the federal government's competence, and damaging to America's standing in the world—not only as a source of nuclear technology and policy expertise but as a leader on global issues of nuclear safety, non-proliferation, and security. Wet storage pools are the most common method for storing SNF in the United States, accounting for about 73% (49,338 MTU) of the current commercial SNF inventory. The remaining 27% (18,112 MTU) of commercial SNF is stored in dry casks on concrete pads or horizontal bunkers. The SNF storage capacities using wet storage pools at U.S. commercial power reactors generally range from approximately 2,000 assemblies to 5,000 assemblies (averaging approximately 3,000 SNF fuel assemblies). Generally, the storage sites include facilities at the 104 licensed operating nuclear power reactor locations where it was generated (see Table 1 and Figure 5 ), as well as 10 "stranded" commercial sites where no reactors operate (including the Morris, IL), and 4 DOE-operated facilities. Of the 74 different sites (some with multiple storage facilities) where commercial spent fuel is stored in the United States, 55 locations employ dry cask storage for at least part of the storage for commercial SNF. There are 27 sites with 36 wet pool storage "facilities" (i.e., in some cases there are multiple wet pool storage "facilities" co-located at individual sites) where wet pool storage is the only technology being used at the site. In addition, SNF is stored at three DOE-owned sites where the reactors ceased operating. Specifically, measured by mass, more than 80% (54,092 MTU vs. 13,358 MTU) of SNF is stored at sites east of the Mississippi River. After the earthquake and tsunami in Japan, the first two of these concerns appeared to be occurring at the Fukushima Dai-ichi facility. The NRC staff identified seven recommendations for near-term action, and offered this overall assessment: "To date the Task Force has not identified any issues that undermine our confidence in the continued safety and emergency planning of U.S. plants … Task Force review is likely to recommend actions to enhance safety and preparedness." Options for How to Store SNF

To consider how SNF is stored, there are essentially two options available: wet storage pools and dry cask. A shift of all SNF older than five years from wet pools to dry storage would more than triple the amount of SNF in dry cask storage. The concerns about consolidated interim storage expressed by some include (1) potentially reducing pressure on decision makers to agree on a permanent repository because the problem will appear to have been "solved" and because of a resulting concern that storage sites would become de facto repositories; (2) protracted delays because of the difficulty in finding a willing host community for SNF storage, which could divert resources from other useful efforts (e.g., safety and security of existing SNF storage and repository siting); and (3) potentially higher net risks if the SNF were to require multiple moves to transport it to the interim site and again to the repository (depending on risk reduction from moving SNF from existing storage locations).
Regardless of the outcome of the ongoing debate about the proposed Yucca Mountain geologic waste repository in Nevada, the storage of spent nuclear fuel (SNF)—also referred to as "high-level nuclear waste"—will continue to be needed and the issue will continue to be debated. The need for SNF storage, even after the first repository is opened, will continue for a few reasons.
The Obama Administration terminated work on the only planned permanent geologic repository at Yucca Mountain, which was intended to provide a destination for most of the stored SNF. Also, the Yucca Mountain project was not funded by Congress in FY2011 and FY2012, and not included in the Administration's budget request for FY2013. Even if the planned repository had been completed, the quantity of SNF and other high-level waste in storage awaiting final disposal now exceeds the legal limit for the first repository under the Nuclear Waste Policy Act (NWPA). The expected rate of shipment of SNF to the repository would require decades to remove existing SNF from interim storage. Accordingly, the U.S. Nuclear Regulatory Commission (NRC) and reactor operators are considering extended SNF storage lasting for more than 100 years.
The debate about SNF typically involves where and how it is stored, as well as what strategies and institutions should govern SNF storage. The earthquake and tsunami in Japan, and resulting damage to the Fukushima Dai-ichi nuclear power plant, caused some in Congress and NRC to consider the adequacy of protective measures at U.S. reactors. The NRC Near-Term Task Force on the disaster concluded it has "not identified any issues that undermine our confidence in the continued safety and emergency planning of U.S. plants." Nonetheless, NRC has accepted a number of staff recommendations on near-term safety enhancement, including requirements affecting spent fuel storage and prevention and coping with station blackout. NRC is not requiring accelerated transfer of SNF from wet pools to dry casks, but the SNF storage data from the last several years indicate that accelerated transfer has already been occurring.
As of December 2011, more than 67,000 metric tons of SNF, in more than 174,000 assemblies, is stored at 77 sites (including 4 Department of Energy (DOE) facilities) in the United States located in 35 states (see Table 1 and Figure 5), and increases at a rate of roughly 2,000 metric tons per year. Approximately 80% of commercial SNF is stored east of the Mississippi River. At 9 commercial SNF storage sites there are no operating nuclear reactors (so-called "stranded" SNF), and at the 4 DOE sites reactor operations largely ceased in the 1980s, but DOE-owned and some commercial SNF continues to be stored at DOE facilities. In the United States, SNF is stored largely at nuclear reactor sites where it was generated. Of the 104 operating nuclear reactors in the United States, all necessarily have wet storage pools for storing SNF (wet pools are required to allow for a safe "cooling off" period of 1 to 5 years after discharge of SNF from a reactor). Wet storage pools are used for storage of approximately 73% (49,338 out of 67,450 metric tons of uranium, or MTU) of the current commercial SNF inventory, whereas the remaining 27% (18,112 MTU) of commercial SNF is stored in dry casks on concrete pads or in vaults. As wet storage pools become filled to capacity using "dense packing" storage methods, dry storage is increasingly being used, although there are 27 sites with 36 wet storage pools with no current dry cask storage capabilities.
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 for the potentially foreseeable future.