Advisers to the Nation on Science, Engineering, and Medicine

The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences.

The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Wm. A. Wulf is president of the National Academy of Engineering.

The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine.

The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Wm. A. Wulf are chair and vice chair, respectively, of the National Research Council.

www.national-academies.org

This page intially left blank

This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The content of the review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report:

Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the report’s conclusions or recommendations, nor did they see the final draft of the report before its release. The review of this report was overseen by Hyla Napadensky, Napadensky Energetics Inc. (retired), and John Ahearne, Sigma Xi. Appointed by the National Research Council, they were responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.

This page intially left blank

During World War II and the Cold War that followed, the United States built large production capabilities for and stockpiles of nuclear weapons. This involved the chemical processing (reprocessing) of the spent nuclear fuel from plutonium production reactors. The highly radioactive wastes from reprocessing were put in underground tanks as neutralized liquor at the Hanford and Savannah River Sites in Washington State and South Carolina, respectively. A separate, but similar, program at the Idaho National Laboratory reprocessed spent nuclear fuel from naval nuclear reactors and experimental and test reactors; most of the waste from these reprocessing activities was converted to a granular form and stored in above-ground bins (tanks inside silos), although some highly acidic waste was left in the facility’s underground stainless steel storage tanks.

At the Hanford and Savannah River Sites, the chemical processes used for extracting key radionuclides changed over time and were applied to different nuclear fuels and targets. As a result, the wastes produced by reprocessing were somewhat different at different times. The liquid wastes were subjected to chemical treatments to inhibit corrosion of the carbon steel tanks and to precipitate key radionuclides. Wastes from different chemical processes or from processing different materials were mixed together; some wastes were reprocessed multiple times for additional separations; and materials such as zeolites and diatomaceous earth were discarded in some tanks. The tanks themselves vary in design, even at one site and within one tank farm. Some waste was intentionally discharged into the ground at Hanford, and there were leaks in the tank farms at each site. Most of the tank wastes now are highly heterogeneous and the conditions in which they are stored vary.

Studies of means to solidify the highly radioactive tank wastes began roughly 50 years ago. Progress has been slow. This is an indication of the complexity and difficulty of the problem. Now the United States is entering a new phase, under very different social, political, and legal conditions than were in place at the time the wastes were created. The Department of Energy (DOE), which is responsible for managing the wastes and their consequent risks, has been operating one facility for immobilizing high-level radioactive waste through vitrification at the Savannah River Site and has finished operation of another at the West Valley Demonstration Project. DOE is building a processing and immobilization facility at Hanford and has recently selected a technology for immobilizing the liquid waste in tanks in Idaho. DOE has cleaned out about 12 of the 246 tanks at the sites, and 2 of the cleaned tanks have been closed by filling them with grout.

Ideally, all wastes would be removed from the tanks. However, it is widely recognized that it is prohibitive in terms of worker risk and economic cost to exhume the tanks or remove all of the wastes from all of the tanks. The debate now is over how much removal of the wastes from the tanks is enough, how much removal of radionuclides from the retrieved waste is enough, and whether grout is an adequate form of residual waste immobilization onsite. In 2004, Congress passed legislation (the Ronald Reagan National Defense Authorization Act for Fiscal Year 2005) to facilitate progress toward tank waste disposal in South Carolina and Idaho, providing a framework for determining what wastes may remain on-site. In the same act, Congress asked the National Academies to evaluate DOE’s plans for some of these wastes at the Savannah River Site, the Hanford Site, and the Idaho National Laboratory.

A committee of 21 volunteers with diverse expertise was charged to fulfill the congressional request, issuing an interim report in 6 months and the final report in one year (see Appendix A for biographical sketches of the committee members). This proved to be a difficult challenge. Due to the complexity of DOE’s tasks, there are many important details in several hundred substantial documents, and some details were not constant throughout the course of the study. Decisions and reviews are continuing even as this report is being published. The committee carried out its task as DOE was working with South Carolina, Idaho, and the U.S.

Nuclear Regulatory Commission on the first waste determinations to be made under the new legislation. DOE and others worked hard to get the committee the information it needed. However, an unfortunate feature of the timing is that some key documents were issued late in the course of the study (after the beginning of September 2005 and through the committee’s review process).

Because of the long time frames in which some of the waste remains hazardous, the committee recognized that the future is uncertain and circumstances, capabilities, and knowledge may continue to change as dramatically in the future as they have in the past. We also recognize that given such limited experience with some of the chemical processes to treat wastes, some being used in these applications for the first time, there is a high degree of technical uncertainty added to the considerable uncertainties about costs and what the society values. We have tried to avoid scientific and engineering hubris in viewing our capabilities to predict what will occur in the future and how man-made objects will perform over these long time frames.

We have refrained from looking holistically at the problem of environmental releases of radioactive and hazardous chemical materials from the sites over time because it was not in our charter. However, we would be remiss if we did not call attention to the other radioactive and hazardous chemicals at the sites that also can pose risks to human health and the environment. As noted in the report, the trade-off between the cost and risk of retrieving and processing tank and bin wastes must take into consideration risks from other waste and contamination already committed to the site.

Time constraints, new developments, and the absence of some information even in the vast quantity of documentation provided necessarily limit the extent to which the committee could answer Congress’s questions. Some related issues, such as seismic concerns, could not be considered. Nevertheless, the report contains important messages that we hope Congress, DOE, and others will find informative and helpful. Some of these messages are reiterated and elaborated from the committee’s interim report. The final report does not reproduce the committee’s finding and recommendation concerning “Class C” concentration limits. The committee stands by them, as indicated in Appendix E, but has nothing further to add on that subject.

The committee thanks the people who provided input to this study, including the many presenters listed in the Appendix D, as well as members of the public who spoke at those meetings. We specifically acknowledge several individuals who helped to coordinate meetings and respond to special requests by the committee: Mark Gilbertson, Randy Kaltreider, and Ken Picha at DOE headquarters; Tom Caldwell, Bill Clark, Ginger Dickert, Peter Hill, Christine Langton, Bill Pearson, Sherri Ross, Terry Spears, and Steve Thomas at the Savannah River Site; Shelly Sherritt and David Wilson at the South Carolina Department of Health and Environmental Control; Anna Bradford, David Esh, and Scott Flanders at the U.S. Nuclear Regulatory Commission; Lorie Cahn, Keith Lockie, and Keith Quigley at the Idaho National Lab; Kathleen Trever at the Idaho Department of Environmental Quality; Ryan Dodd, Bill Hewitt, Fred Mann, Roger Quintero, and Roy Schepens at the Hanford Site; Suzanne Dahl, Jane Hedges, and Michael Wilson at the Washington Department of Ecology; Russell Jim of the Yakama Indian Nation; and Ken Niles at State of Oregon Department of Energy.

Finally, the committee thanks the members of its staff— Laura Llanos, Micah Lowenthal, Barbara Pastina, Darla Thompson, Marili Ulloa, and John Wiley—all of whom worked long hours to support the committee throughout the study. In particular, we thank Micah and Barbara for their work in directing the study and Laura for ensuring that meetings went smoothly. We also want to acknowledge Kevin Crowley, director of the Nuclear and Radiation Studies Board, for his assistance at several points. This study was a large and challenging task that the committee could not have completed without their support.

Frank L. Parker, Chair

Committee on the Management of

Certain Radioactive Waste Streams

Stored in Tanks at Three Department of

Energy Sites

This page intially left blank