Analysis of U.S. Experience with Spent Fuel
John F. Ahearne
Sigma Xi: The Scientific Research Society
The United States has 103 reactors at 65 sites, representing a generation capacity of about 88 GWe. As of December 2001 the United States was storing approximately 45,000 metric tons of heavy metal of spent fuel from civilian nuclear power plants. As of December 31, 2001, 42,000 metric tons of heavy metal was stored in pools, with only 3000 in dry casks. Use of dry casks is growing, however, as utility pools fill up. A repository or offsite storage facility is not available.
Table 1 summarizes the U.S. fuel, along with that in Russia. A smaller amount of spent fuel from the U.S. weapons program is also being stored for eventual disposal. Most of this fuel has been reprocessed to extract the plutonium or highly enriched uranium.
There are many nuclear power plant designs used in the United States, but all except three are and have been light water reactors, either pressurized water reactors or boiling water reactors. The fuel elements are zirconium alloy tubes, containing ceramic UO2 pellets of 3–5 percent enrichment. Current burn-up goes to at least 45,000 MWD per metric ton of heavy metal. The three nonlight water reactors were
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Fermi 1, a 60 MWe breeder, closed in 1972
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Peach Bottom 1, a 40 MWe high-temperature gas-cooled reactor, closed in 1974
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Fort St. Vrain, a 330 MWe high-temperature gas-cooled reactor, closed in 1989
TABLE 1 Amounts of Spent Nuclear Fuel in Storage and Rate at Which the Amount is Increasing
Type of Spent Nuclear Fuel |
Russian Federation Spent Nuclear Fuel (metric tons of heavy metal) |
United States Spent Nuclear Fuel (metric tons of heavy metal) |
Power Reactor |
14,000 + 850 per year |
45,000 + 2000 per year |
Naval |
70 + fuel from 15–18 nuclear power stations per year |
19.5 + 45.5 over 33 yearsa |
Production Reactor |
Not availableb |
2100 + 0 per year |
Research Reactor |
28,500 assemblies |
23 + 0.07 per year |
aCiting an annual rate for discharges from naval reactors may not be accurate so the expected total for a known period is given. bApproximately 1.5 metric tons of separated plutonium are produced each year by the three dual purpose reactors. The spent nuclear fuel from these reactors is stored only briefly before going through chemical separations. SOURCE: National Research Council. End Points for Spent Nuclear Fuel and High-Level Radioactive Waste in Russia and the United States. Washington, D.C.: The National Academies Press, 2003, Table 1.1. |
GOVERNMENT-MANAGED SPENT FUEL
The U.S. Department of Energy (DOE) currently manages about 2500 metric tons of heavy metal of spent fuel, of about 250 different types. This includes fuel from plutonium production reactors, naval reactors, and research and demonstration reactors.
The United States halted reprocessing to obtain weapons plutonium in 1988, and the Hanford reprocessing canyons shut down in 1989. One Savannah River canyon continues to operate for processing unstable fuel. The Idaho Chemical Processing Plant, which had been used for naval fuel, shut down in 1992.
Table 2 lists quantities of U.S. government fuel and current disposition plans.
NAVAL REACTORS
The United States produced 191 submarines each with 1 reactor, 8 aircraft carriers with 2 reactors each and 1 carrier with 8 reactors, 9 cruisers with 2 reactors each, a deep submergence research vessel with 1 reactor, and 1 civilian cargo ship with 1 reactor. The only nuclear ships still in service are the carriers and 72 submarines.1
All navy spent fuel is shipped to Idaho National Laboratory for storage. After decommissioning the ship and removal of the fuel, the reactor compartment is removed and shipped to the Hanford site for storage.
TABLE 2 Quantities of U.S. Government Spent Nuclear Fuel and Unirradiated Nuclear Fuel Grouped According to Near-Term Managementa
Near-Term Management |
Quantity (metric tons of heavy metal) |
Examples |
Processed to HLW at ANL-W |
61.3 |
Sodium bonded EBR-II and FFTF fuel |
In foreign research reactors |
14.3 |
HEU in Al plates in France, Pakistan, and four other nations |
Storage until repository disposal (no further processing) |
2465 |
N-reactor fuel, fuel from isotope production reactors, ANP fuel |
Special treatment |
0.041 |
Cutting fines from SNF assay, MSRE fuel |
Processed to HLW at SRS |
23.9 |
Declad EBR-II uranium metal fuel, declad uranium/thorium fuel |
Treatment at ORNL Y-12 |
0.27 |
Failed fuel from Roverb |
Unknown |
996 |
Unirradiated fuel for the N-reactor, FFTF, EBR-II |
Unknown |
25.2 |
Various fuel forms (unclad natural uranium, polyethylene matrixes, aluminum) from test piles and research reactors, also unirradiated but damaged fuel (managed as spent fuel) |
aAll wastes are planned ultimately to be disposed of in a repository. bRover was a nuclear rocket prototype reactor with niobium-based fuel. NOTE: ANL-W: Argone National Laboratory West; ANP: Aircraft Nuclear Propulsion; EBR-II: Experimental Breeder Reactor-II at Argonne National Laboratory West; FFTF: Fast Flux Test Facility at Hanford; HEU: Highly Enriched Uranium; HLW: High-Level Waste; MSRE: Molten Salt Reactor Experiment; ORNL: Oak Ridge National Laboratory; SNF: Spent Nuclear Fuel; SRS: Savannah River Site. SOURCE: U.S. Department of Energy, Office of Spent Fuel Management. Spent Fuel Database (SFD), Version 4.2.0. March 25, 2002; National Research Council. End Points for Spent Nuclear Fuel and High-Level Radioactive Waste in Russia and the United States. Washington, D.C.: The National Academies Press, 2003, Table 2-4. |
RESEARCH REACTORS
In the 1970s the United States had 70 research reactors at universities and several dozen research and test reactors at government and industrial facilities. Today 36 are operating, and 19 are being closed down. Most are small, with the largest being 20 MWth. The United States has provided fuel to 110 research
reactors in other countries, and there is a program for the highly enriched uranium fuel to be shipped back to the United States. When the fuel is returned, it is sent to Savannah River or Idaho for storage. Approximately 2.7 metric tons of heavy metal of highly enriched uranium fuel are still in other countries.
DISPOSITION OF 34 METRIC TONS OF WEAPONS PLUTONIUM
The United States began to consider various approaches for disposition of weapons plutonium in the early 1990s and asked the National Academies to study the possible approaches. The study examined vitrification and various reactor options. Following this study and development of technical information by the national laboratories, in 1997 DOE announced a dual-track strategy:
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fabrication of clean plutonium into MOX (mixed oxide) fuel and use in civilian reactors (26 metric tons)
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vitrification of the plutonium thought to be unsuitable for MOX fuel (8 metric tons)
In 2001 DOE concluded that this plan would be too expensive and would take too long, and decided to proceed only with MOX. Of the 8 metric tons of unsuitable plutonium, 6.2 metric tons will be processed and then made into MOX fuel. Other plutonium will be used to make up the required total of 34 metric tons; the 1.8 metric tons of impure plutonium do not yet have a disposal path.
The U.S. program to build a MOX facility has not developed as rapidly as hoped. The plant design is currently in the licensing process.
LIQUID HIGH-LEVEL WASTE
Production of nuclear weapons has also produced large volumes of liquid high-level waste. Table 3 shows the quantities of liquid high-level waste stored at sites in the United States.
YUCCA MOUNTAIN, HIGH-LEVEL WASTE, AND THE NATIONAL ACADEMIES
For over 80 years the U.S. government has asked the National Research Council, the study arm of the National Academies, to provide advice on issues of importance to the government. In the area of radioactive material the Board on Radioactive Waste Management (BRWM) has produced over 100 reports, primarily on high-level waste and the environmental management issues relating to legacy wastes, those wastes from the nuclear weapons program. I am glad to note that Academician Laverov is a member of BRWM.
I will now address the end point for spent nuclear fuel as seen in the United States. In 1955 the National Research Council recommended isolation in stable
TABLE 3 Quantities of High-Level Waste (HLW) Stored at Sites in the United States
Site |
HLW in Tanks (cubic meters) |
Vitrified HLW (canisters) |
Total Radioactivity (× 108 Ci) |
Percent of Total Volume |
Percent of Total Radioactivity |
Hanford Site |
200,000 |
0 |
384 |
58.9 |
15.8 |
Savannah River Site |
130,000 |
719a |
1730 |
38.3 |
71 |
Idaho National Engineering and Environmental Laboratory |
9360 |
0 |
300 |
2.8 |
12.3 |
West Valley |
109b |
241b |
23.3 |
<0.1 |
1 |
Demonstration Project |
|||||
Total |
339,469 |
960 |
2437.3 |
100 |
100.1 |
a1337 as of October 2002. bHLW from the tanks at West Valley has been vitrified in 275 canisters. Residual HLW encrusted on the tanks is being characterized and sluiced. SOURCE: U.S. Department of Energy, Office of Environmental Management. Summary Data on the Radioactive Waste, Spent Nuclear Fuel, and Contaminated Media Managed by the U.S. Department of Energy. April 2001. National Research Council. End Points for Spent Nuclear Fuel and High-Level Radioactive Waste in Russia and the United States. Washington, D.C.: The National Academies Press, 2003, Table 3.3. |
geologic formations as the approach for handling high-level waste. In 1982 the U.S. Waste Policy Act directed the DOE to develop a deep geologic repository. In 1987, after several years of screening for potential sites and then narrowing to four, the U.S. Congress selected the Yucca Mountain Site in Nevada, adjacent to the Nuclear Test Site, where the United States has conducted many above- and below-ground nuclear weapons tests.
In 1990 BRWM produced a 40-page report, Rethinking High-Level Radioactive Waste Disposal,2 which had a major impact on the DOE program. The report begins as follows:
There is a worldwide scientific consensus that deep geological disposal, the approach being followed in the United States, is the best option for disposing of high-level radioactive waste (HLW). There is no scientific or technical reason to think that a satisfactory geological repository cannot be built.
The report further stated that the U.S. program as conceived and implemented in the past is unlikely to succeed. Note that this report, as do many, seems to address only science and technology; the political and other social science aspects were not highlighted.
Since the report was written, the DOE program did change, but it still has had problems, both technical and political. The United States appears to be the only country to have taken the approach of writing detailed regulations specifying what must be shown in the license application before the requirements for the general site data are determined. “As a result, the U.S. program is bound by requirements that may be impossible to meet.”3
At the request of Congress the National Research Council conducted a study on what should be the technical bases for Yucca Mountain requirements and produced Technical Bases for Yucca Mountain Standards, known as the TYMS report,4 in 1995. In addition to recommending a risk-based approach rather than a dose-based approach, the study advised on how to treat intrusion (specifically, do not make it a licensing requirement) and integrated population dose (specifically, do not count carbon 14 in all of the world’s population). Although the U.S. Environmental Protection Agency (EPA) eventually disregarded the report, the report did introduce the issues to a wide audience, including many in Congress who had been unaware of the issues. It may eventually be used in court.
In 1996 the National Research Council published a large report, Nuclear Wastes: Technologies for Separations and Transmutations (the STATS report),5 which addressed whether science and technology could avert the need for a long-term geologic repository. The report recommended that DOE continue to develop a repository for spent nuclear fuel, since no science and technology concept would eliminate that need; that retrievability in the repository should be on the order of 100 years; and that research and development should continue on science and technology concepts.
The next major study was published in 2001, Disposition of High-Level Waste and Spent Nuclear Fuel: The Continuing Societal and Technical Challenges.6 This was an international study and included members from many countries (Academician Laverov was a member). This study reviewed the arguments for and against geologic repositories, reviewed the status of national programs, and recommended processes for governments to follow and to develop geologic repositories. These recommendations included technical topics and also political and social science-based topics. In this second report the committee recognized that involving the local public is essential if there is to be successful site selection and development.
THE U.S. PROCESS
In 2002 Secretary of Energy Spencer Abraham recommended to President Bush that DOE should go forward with developing an application to construct the Yucca Mountain repository. The president accepted that recommendation and forwarded it to Congress. As the Waste Policy Act provides, the host state, Nevada, could refuse to accept the repository, a veto that could be overridden by the Congress. Nevada did veto the recommendations, and finally the Congress
did override it. The issues, often couched in technical language, were in my opinion primarily political. (The congressional and DOE approaches are case studies of how not to work with the public. These are classic examples of the model characterized as “decide, announce, and defend” in which the interested and affected public is not asked to contribute before the decision is made—only after.)
DOE now must submit a license application to the Nuclear Regulatory Commission, which by law has three to four years to review it. A legal hearing, in our terms an adjudicatory hearing, will be held to decide whether the DOE application meets the licensing requirements. This is the first such license application, and with intense public interest, the commission will move carefully.
If the application is successful and a license to construct is issued, it will take several more years to construct the above-ground facilities and extend the existing 11 km of tunnels. DOE must then apply for a license to emplace waste.
The current schedule—which DOE has had for several years—is for first fuel going underground in 2010. A recent National Research Council report noted, “Most external commenters believe this ambitious schedule is unrealistic based on the time needed for each step. In addition, several lawsuits that attempt to block the various steps in the process have been filed.”
Other issues regarding Yucca Mountain include working on the transportation of spent nuclear fuel to Yucca Mountain and the security of Yucca Mountain and related facilities against terrorist attacks.
The latest Academy study was released earlier this year, One Step at a Time: The Staged Development of Geologic Repositories for High-Level Radioactive Waste.7 While addressing the general case of developing a repository, the study has direct applicability to Yucca Mountain. The study recommends an approach called adaptive staging. There is no simple definition of this concept. It provides flexibility in responding to new information, allows examination of performance and consideration of new knowledge before moving to the next step, and provides more access by the public to the repository program. To an engineer this looks like a feedback loop.
OTHER STUDIES
The National Research Council has also studied both narrower and broader issues. Examples of narrower studies are
M. Levenson and K. D. Crowley. Research Reactor Aluminum Spent Fuel: Treatment Options for Disposal. Washington, D.C.: National Academy Press, 1998.
National Research Council. Research Needs in Subsurface Science. Washington, D.C.: National Academy Press, 2000.
National Research Council. Characterization of Remote-Handled Waste for the Waste Isolation Pilot Plant (WIPP). Washington, D.C.: National Academy Press, 2002.
Examples of broader studies are
National Research Council. A Strategic Vision for Department of Energy Environmental Quality Research and Development. Washington, D.C.: National Academy Press, 2001. This report addressed all the programs that relate to the environmental quality research and development portfolio across many DOE divisions.
National Research Council. Making the Nation Safer: The Role of Science and Technology in Countering Terrorism. Washington, D.C.: The National Academies Press, 2002. This report recommends how science and technology could contribute to many areas and addresses the vulnerabilities to terrorist threats; one section addresses radiological threats.
National Research Council. End Points for Spent Nuclear Fuel and High-Level Radioactive Waste in Russia and the United States. Washington, D.C.: The National Academies Press, 2003. This study was cochaired by Academician Laverov; the Russian members of the committee included Academician Melnikov, Academician Myasoedov, and Dr. Pek. The study provides a high-level view of the entire fuel cycle in both countries and recommends near-term and long-term actions.