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Jan. 28, 2016


Report Affirms the Goal of Elimination of Civilian Use of Highly Enriched Uranium and Calls for Step-wise Conversion of Research Reactors Still Using Weapon-grade Uranium Fuel; 50-year Federal Roadmap for Neutron-based Research Recommended


WASHINGTON – Efforts to convert civilian research reactors from weapon-grade highly enriched uranium (HEU) to low enriched uranium (LEU) fuels are taking significantly longer than anticipated, says a congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine.   The report calls for the federal government to take immediate steps to convert civilian research reactors currently using weapon-grade HEU fuel to a lower-enriched HEU fuel while awaiting the qualification of new LEU fuel.  Additionally, the White House Office of Science and Technology Policy (OSTP) should develop a long-term strategy to evaluate future civilian needs for neutrons to meet U.S. science and technology objectives and how these could best be provided by research reactors and other sources, said the committee that conducted the study and authored the report.


Since 1978, U.S. policy and reactor conversion programs have worked to minimize, and phase out where possible, the use of HEU in fuel for civilian research reactors. These reactors use weapon-grade HEU — which is enriched to 90 percent or greater uranium-235 — to produce neutrons vital to research and other civilian applications.  Eliminating HEU use in these reactors by converting them to fuel containing LEU — enriched to less than 20 percent uranium-235 — would reduce the risks that this material could be diverted for illicit use, for example in nuclear explosive devices.  Worldwide, over 90 civilian research reactors have been converted to LEU fuel or shut down.  However, 74 civilian research reactors, including eight in the United States, continue to use HEU fuel.


Obstacles for converting the remaining civilian research reactors from HEU to LEU fuel are both technical and nontechnical, the report notes.  Some reactors using HEU fuel require the successful development of new, higher-density LEU fuel to maintain performance after conversion; these reactors are referred to as high performance research reactors.  For others, progress toward conversion is hindered by nontechnical obstacles such as economic and political motivations.


The United States is developing high-density LEU fuel that could be used to convert all of the currently operating U.S. high performance research reactors, but manufacturing this fuel will be challenging, the report notes.  Somewhat lower density LEU fuels in development in Europe and South Korea might be suitable for the conversion of some, but not all, U.S. high performance research reactors.  The Office of Conversion, which is part of the U.S. Department of Energy’s (DOE) Material Management and Minimization Office, should monitor the development of European and South Korean LEU fuels for possible use as a backup option if there are unexpected delays in the U.S. fuel development effort.


DOE now estimates that it will take another 20 years to convert the remaining HEU-fueled civilian research reactors throughout the world and over 15 years to convert those in the United States to LEU fuel.  The report recommends an interim solution to accelerate the removal of weapon-grade HEU from civilian applications until new high-density LEU fuel is available: convert the high performance research reactors in the United States and Europe using an existing, qualified HEU fuel with uranium-235 enrichments of 45 percent or less.  Nearly all of the high performance research reactors currently operating with HEU fuel could use this intermediate fuel without significant impact to their missions, the report estimates.


The current fleet of aging U.S. research reactors fueled by HEU is managed by a number of different universities and U.S. government agencies.  DOE, for example, has authority over only half of these reactors.  Therefore, the report recommends that OSTP take the lead in developing a 50-year cross-agency strategy to ensure the future availability of U.S. neutron sources, potentially including civilian research reactors.


Over 40 percent of the remaining HEU-fueled civilian research reactors in the world are located in Russia.  However, conversion of its domestic reactors has both technical and nontechnical obstacles: Russia has several high performance research reactors and conversion is not a high priority for the Russian government.  U.S. collaborations with Russia on research reactor conversion have all but ceased during the past year, and U.S. funding to support conversion of Russian civilian research reactors has decreased.  The report recommends that the United States encourage and facilitate periodic workshops and meetings to bring Russian and U.S. scientists together to jointly study the risks and benefits of LEU conversion and identify opportunities for collaborations.


The report recognizes the challenges faced by the DOE’s Office of Conversion, which is responsible for managing the U.S. government’s LEU fuel development and civilian research reactor conversion efforts.  The conversion program is expected to operate for several more decades based on current time lines and has many technical risks.  This program can be strengthened by utilizing qualified, independent, and diverse external experts to conduct technical reviews of all aspects of the program, including LEU fuel development and fabrication, material recycling, and spent-fuel management, the report says.


The American Medical Isotopes Production Act of 2012 mandated that the Academies carry out an assessment of the progress being made by DOE and others to eliminate all worldwide use of HEU in research reactor fuel and medical isotope production facilities.  It was later determined that two separate studies would be conducted to support this mandate.  The current report examines the status of conversion of research reactors to LEU.  Another report examining the status of medical isotope production without HEU targets will be issued later this year.


The study was sponsored by the U.S. Department of Energy.  The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine.  They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln.  For more information, visit A committee roster follows.



Jennifer Olson, Media Consultant

Emily Raschke, Media Assistant

Office of News and Public Information

202-334-2138; email<>

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Copies of Reducing the Use of Highly Enriched Uranium in Civilian Research Reactors are available from the National Academies Press at or by calling 202-334-3313 or 1-800-624-6242. Reporters may obtain a copy from the Office of News and Public Information (contacts listed above).


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Division on Earth and Life Studies

Nuclear and Radiation Studies Board


Committee on Current Status of and Progress Toward Eliminating Highly Enriched Uranium Use in Fuel for Civilian Research and Test Reactors


Julia M. Phillips1 (chair)

Vice President and Chief Technology Officer

Sandia National Laboratories (retired)

Albuquerque, N.M.


Pablo Adelfang

International Atomic Energy Agency (retired)

Vienna, Austria


Gerald Gabrielse2

Leverett Professor of Physics

Department of Physics

Harvard University

Cambridge, Mass.


Alexander Glaser


Woodrow Wilson School of Public and International Affairs and

Department of Mechanical and Aerospace Engineering

Princeton University

Princeton, N.J.


David W. Johnson, Jr.1


Journal of the American Ceramic Society

Westerville, Ohio


Patrick M. Lemoine

Retired Commissariat à l'Energie Atomique et aux Energies Alternatives (retired)

Paris, France


William R. Martin

Professor of Nuclear Engineering and Radiological Sciences

Department of Nuclear Engineering

University of Michigan

Ann Arbor


Roger Pynn


Center for the Exploration of Energy and Matter

Indiana University



William H. Tobey

Senior Fellow

Belfer Center for Science and International Affairs

John F. Kennedy School of Government

Harvard University

Cambridge, Mass.


Paul P. H. Wilson


College of Engineering

University of Wisconsin





Jennifer Heimberg

Study Director


1Member, National Academy of Engineering

2Member, National Academy of Sciences