DOE has a vast complex of sites across the nation dedicated to the nuclear weapons program. DOE largely ceased production of plutonium and enriched uranium by 1992, but the waste remains at the sites. Most of the tanks in which the waste is stored have already exceeded their design life. For example, many of Hanford’s and Savannah River’s tanks were built in the 1940s to 1960s and were designed to last 10-40 years. Leaks from some of these tanks were first detected at Hanford in 1956 and at Savannah River in 1959. Given the age and deteriorating condition of some of the tanks, there is concern that some of them will leak additional waste into the soil, where it may migrate to the water table and, in the case of the Hanford Site, to the Columbia River. Responsibility for the high-level waste produced at DOE facilities is governed primarily by federal laws, including the Atomic Energy Act of 1954. These laws established responsibility for the regulatory control of radioactive materials including DOE’s high-level waste and assigned the Nuclear Regulatory Commission (NRC) the function of licensing facilities that are expressly authorized for long-term storage of high-level radioactive waste generated by DOE. In addition, the Nuclear Waste Policy Act of 1982 defined high-level radioactive waste. Various other federal laws, including the Resource Conservation and Recovery Act of 1976, guide how DOE must carry out its cleanup program. The high-level waste cleanup program is under the leadership of the Assistant Secretary for Environmental Management. It involves consultation with a variety of stakeholders, including the Environmental Protection Agency, state environmental agencies where DOE sites are located, county and local governmental agencies, citizen groups, advisory groups, and Native American tribes. The waste in the tanks at the Hanford and Savannah River sites and the Idaho National Laboratory near Idaho Falls is a complex mixture of radioactive and hazardous components. DOE’s process for preparing it for disposal is designed to separate much of the radioactive material from other waste components. Nearly all the radioactivity in the waste originates from radionuclides with half-lives of about 30 years or less. The relatively short half-lives of most of the radionuclides in the waste means that within 30 years, about 50 percent of the current radioactivity will have decayed away, and within 100 years this figure will rise to more than 90 percent. Figure 1 shows the pattern of decay, using 2002 to 2102 as the 100-year period. Extending the analysis beyond the 100-year period shown in the figure, in 300 years, 99.8 percent of the radioactivity will have decayed, leaving 0.2 percent of the current radioactivity remaining. Despite the relatively rapid decay of most of the current radioactivity, some radionuclides have half-lives in the hundreds of thousands of years and will remain dangerously radioactive for millions of years. Some of these long-lived radionuclides are potentially very mobile in the environment and therefore must remain permanently isolated. If these highly mobile radionuclides leak out or are released into the environment, they can contaminate the soil and water. DOE plans to isolate the radioactive components and prepare the waste for disposal through a multi-step treatment process. DOE expects this process to concentrate at least 90 percent of the radioactivity into a much smaller volume that can be permanently isolated for at least 10,000 years in a geologic repository. The portion of the waste not sent to the geologic repository will have relatively small amounts of radioactivity and long-lived radionuclides. Based on current disposal standards used by the NRC, if the radioactivity of this remaining waste is sufficiently low, it can be disposed of on site near the surface of the ground, using less complex and expensive techniques than those required for the highly radioactive portion. DOE plans to dispose of this waste on site in vaults or canisters, or at other designated disposal facilities. DOE has successfully applied this process in a demonstration project at the West Valley site in New York State. At West Valley, separation of the low-activity portion from the high-level portion of the waste reduced by 90 percent the quantity of waste requiring permanent isolation and disposal at a geologic repository. The high-level portion was stabilized in a glass material (vitrified) and remains stored at the site pending completion of the high-level waste geologic repository and resolution of other issues associated with disposal costs. The remaining low-activity portion was mixed with cement-forming materials, poured into drums where it solidified into grout (a cement-like material), and remains stored on site, awaiting shipment to an off-site disposal facility. DOE’s new initiative, implemented in 2002, attempts to address the schedule delays and increasing costs DOE has encountered in its efforts to treat and dispose of high-level waste. This initiative is still evolving. As of April 2003, DOE had identified several strategies to help reduce the time needed to treat and dispose of the waste. Based on these strategies, DOE estimated that it could reduce the waste cleanup schedule by about 20 to 35 years at its high-level waste sites and save about $29 billion compared to the existing program baseline. While some degree of savings is likely if the strategies are successfully implemented, the extent of the savings is still uncertain. Many of DOE’s proposals to speed cleanup and reduce environmental risk involve ways to do one or more of the following: Deal with some tank waste as low-level or transuranic waste, rather than as high-level waste. Doing so would eliminate the need to vitrify the waste for off-site disposal in the geologic repository for high-level waste. Complete the waste treatment more quickly by using additional or supplemental technologies. For example, DOE’s Hanford Site is considering using up to four supplemental technologies, in addition to vitrification, to process its low-activity waste. DOE believes these technologies are needed to help it meet a schedule milestone date of 2028 agreed to with regulators to complete waste processing. Without these technologies, DOE believes waste treatment would not be completed before 2048. Segregate the waste more fully than initially planned and tailor waste treatment to each of the waste types. By doing so, DOE plans to apply less costly treatment methods to waste with lower concentrations of radioactivity. Close waste storage tanks earlier than expected, thereby avoiding the operating costs involved in maintaining the tanks and monitoring the wastes. Table 1 summarizes the estimated cost savings for each DOE site if accelerated proposals for cleaning up high-level waste are successfully implemented. Our review indicates that DOE’s current estimate of $29 billion may not yet be reliable and that the actual amount to be saved if DOE successfully implements the alternative waste treatment and disposal strategies may be substantially different from what DOE is projecting. We have several concerns about the reliability and completeness of the estimate. These concerns include the accuracy of baseline cost estimates from which savings are calculated, whether all appropriate costs are included in the analysis, and whether the savings estimates properly reflect the timing of the savings or uncertainties. DOE’s current lifecycle cost baseline is used as the base cost from which potential savings associated with any improvements are measured. However, in recent years, we and others have raised concerns about the reliability of DOE’s baseline cost estimates. In a 1999 report, we noted that DOE lacked a standard methodology for sites to use in developing their lifecycle cost baseline, raising a concern about the reliability of data used to develop these cost estimates. DOE’s Office of Inspector General also raised a concern in a 1999 review of DOE project estimates, noting that several project cost estimates examined were not supported or complete. DOE acknowledged in its February 2002 review of the cleanup program that baseline cost estimates do not provide a reliable picture of project costs. Some of DOE’s savings may be based on incomplete estimates of the costs for the accelerated proposals. According to Office of Management and Budget (OMB) guidance on developing cost estimates, agencies should ensure that all appropriate costs are addressed in the estimate. However, DOE has not always done so. For example, the Idaho National Laboratory’s estimated savings of up to $7 billion is based, in large part, on eliminating the need to build a vitrification facility to treat its waste. However, the waste may have to undergo an alternative treatment method before it can be accepted at a geological repository, and the Idaho National Laboratory is considering four different technologies for doing so. Nevertheless, DOE’s current savings estimate reflects the potential cost of only one of those technologies. DOE has not yet developed the costs of using any of the other waste treatment approaches. DOE noted that the accelerated lifecycle estimate could likely change depending on which one of the technologies is selected and the associated costs of treating the waste are developed. According to OMB guidance, agencies should ensure that the timing of when the savings will occur is accounted for, that uncertainties are recognized and quantified where possible, and that nonbudgetary impacts, such as a change in the level of risk to workers, are quantified, or at least described. We found problems in all three areas. Regarding the time value of money, applying OMB guidance would mean that estimates of savings in DOE’s accelerated plans should reflect a comparison of its baseline cost estimate with the alternative, expressed in a “present value,” where the dollars are discounted to a common year to reflect the time value of money. Instead, DOE’s savings estimates generally measure savings by comparing dollars in different years. For example, the Savannah River Site estimates a savings of nearly $5.4 billion by reducing by 8 years (from 2027 to 2019) the time required to process its high-level waste. Adjusting the savings estimate to present value in 2003 results in a savings of $2.8 billion in 2003 dollars.