As the first country to harness the power of the atom, the United States was also the first to enrich uranium. Today it continues to use Highly Enriched Uranium (HEU) for both military and civilian purposes. Washington has, however, been spearheading programs aimed at phasing out civilian uses of HEU across the globe, and has made considerable progress towards eliminating HEU use in civilian U.S. research reactors. Furthermore, the United States has played a central role in including language pertaining to the minimization of civilian HEU use and the promotion of reactor conversion in UN Security Council Resolution 1887, the 2010 Nuclear Security Summit Communiqué, and the 2010 NPT Review Conference Final Document.

The United States ended HEU production in 1992, and today only two U.S. civilian research reactors require HEU based fuel.[1] The United States most recently revealed its HEU stocks in January 2006 in a report released by the United States Department of Energy (DoE). The report indicated that as of 30 September 2004, the total U.S. HEU inventory was 686.6 metric tons (MT), containing 590.5 MT of uranium-235.[2] These materials continue to be used in both the military and civilian sectors.

Overview of United States HEU Holdings

In 2006 a DoE report, written in 1996 and titled "Highly Enriched Uranium: Striking a Balance," was released to the public.[3] It contained a comprehensive public declaration of U.S. civilian and military HEU holdings. The report was then updated in 2006 by a subsequent report titled "Highly Enriched Uranium Inventory" (hereafter referred to as the "HEU Report").[4]

According to the two documents, U.S. HEU stocks can be divided into two categories - required and surplus.[5] Required HEU is defined as material that is currently in active use or for which there is planned future use in weapons or other military programs. Surplus HEU is no longer required by the DoE, and is scheduled for disposition either through blending or disposal operations. Inventory figures are, however, in a perpetual state of flux: Reactor burnup, discards to waste, and downblending from HEU to Low Enriched Uranium (LEU) continually contribute to reducing total HEU stocks. Simultaneously, the repatriation of U.S. produced HEU from abroad contributes to driving total stocks upwards.[6]

The HEU report claimed that in September 2004 the United States possessed a stockpile of 686.6 MT, the majority of which was for use in weapons and naval reactor fuel.[7] It also stated that the total quantity of HEU removed from the U.S. inventory between 1945 and September 2004 was 277.7 MT.[8] This material was removed for a variety of purposes including downblending, re-feed at enrichment plants, nuclear tests, naval reactor use, and normal operating losses.[9]

As of September 2004, the United States had downblended approximately 33.3 MT of HEU.[10] This process primarily took place at the Oak Ridge Y-12 Plant, the Oak Ridge Gaseous Diffusion Plant, and the Portsmouth Gaseous Diffusion Plant.[11] Most HEU downblending in the United States was undertaken in order to produce LEU for reactor fuel.

Military HEU
The United States ceased producing highly enriched weapons grade uranium in 1964, and this was followed by an end to plutonium production in 1988.[12] Nevertheless, the Department of Defense (DoD) continues to utilize existing HEU stocks for military purposes, both in nuclear warheads and in its Naval Nuclear Propulsion Program. Although France now uses LEU in its naval reactors the United States does not, claiming that it would cause greater occupational radiation exposure and additional waste.[13] This continued use in the military sphere has a negative impact on the U.S. government's diplomatic attempts to encourage other states to phase out their use of HEU.

In 1996, approximately 88 percent of the U.S. HEU inventory was located at the Y-12 Plant in Oak Ridge, and was in the custody of the DoD. The 651.6 metric tons located at Y-12 in 1996 was in the form of weapons, dismantled weapon parts, naval reactors, canned oxides, combustibles stored in drums, and canned residues.[14] The International Panel on Fissile Materials estimated that in 2007 the United States had approximately 478 metric tons of military HEU that included 100 metric tons in spent naval reactor fuel. It is claimed that 250 metric tons continued to be made available for use in weapons, which is consistent with the estimated 10,000 warheads in the U.S. active and reserve stockpiles.[15]

Civilian HEU
The United States does not voluntarily declare its HEU holdings to the IAEA as part of its annual declaration of plutonium stocks (INFCIRC/549). As a result, its civilian holdings are less transparent than those of France, Germany and the United Kingdom. However, the International Panel on Fissile Materials estimated that in 2010 the United States had approximately 20 MT of civilian HEU.[16]

HEU Production

When the United States ceased production of weapons grade HEU in 1964, it had accumulated 580 MT of weapons grade HEU enriched to 90 percent or more.[17] All HEU production in the United States (at enrichment levels above 20% U-235) stopped in 1993, and the DoE considers current stocks adequate to meet non-weapons requirements for the next 150 years or more.[18] According to the DoE's 1996 report, between 1945 and 1996 the United States produced 1,045.4 MT of HEU containing 859.2 MT of U-235.[19] The majority of this was enriched between 1956 and 1964 at the Oak Ridge and Portsmouth Gaseous Diffusion Plants. This period accounts for approximately 70 percent of the total amount produced by the United States.[20] HEU produced at the Oak Ridge Y-12 Plant in Tennessee and the Portsmouth plant in Ohio was primarily for use in nuclear weapons, naval reactors, and other reactor fuels.[21] The only U.S.-owned uranium enrichment facility in operation in the United States is the Paducah Gaseous Diffusion Plant in Kentucky. Although Paducah is owned by the DoE, it is leased to the United States Enrichment Corporation (USEC). This plant only produces LEU to be used in reactor fuel for commercial power plants in the United States and elsewhere.[22]

However, USEC is currently constructing a gas centrifuge enrichment plant close to the site of the Portsmouth Diffusion Plant in Ohio.[23] The USEC facility was supposed to be brought online in 2010, but was subsequently delayed after the DOE denied the company a $2 billion loan guarantee in July 2010. This was due to the DOE's assessment that USEC had insufficient operating experience. USEC has since re-submitted its loan guarantee application.[24]

In addition to U.S. companies, the European consortium Urenco has already constructed an enrichment facility in the United States, and Areva plans to begin constructing an additional enrichment plant in 2011.[25] In June 2010, operations began at Urenco's uranium centrifuge enrichment facility in Eunice, New Mexico. This is the first new uranium enrichment facility in the United States since 1956, and is projected to reach an output capacity of 5.9 million SWU per year.[26] Areva is also planning to construct an enrichment facility at Idaho Falls, Idaho, that will produce 6.6 million SWU per year. Areva is currently awaiting the outcome of its application for a construction and operating license from the U.S. Nuclear Regulatory Commission.[27]

HEU Commerce

Although the Atomic Energy Act of 1946 (McMahon Act) sought to maintain the U.S. nuclear monopoly following the conclusion of World War II, this policy was reversed by the 1953 Atoms for Peace initiative, which began to promote nuclear energy worldwide. Under Atoms for Peace, the United States provided technical assistance to states that agreed to forego the development of nuclear weapons. This was followed by a 1954 amendment to the Atomic Energy Act that allowed for bilateral nuclear agreements with allies.[28]

Although Atoms for Peace initially only envisioned the export of LEU fuel, this policy was amended following the construction of high-powered research reactors that required low density uranium fuels enriched to 90-93 percent. As a result, in the mid-1960s the United States began to export HEU fuel for use in research reactors and became the world's largest supplier.[29] However, the 1978 Nuclear Non-Proliferation Act established a requirement for full-scope safeguards in the recipient country as a condition for all U.S. nuclear exports. Also in 1978, concerns about the proliferation potential of U.S. HEU exports culminated in the creation of the Reduced Enrichment for Research and Test Reactors (RERTR) Program, an effort to reduce and eliminate the use of HEU in the civilian sphere worldwide.[30]

In October 1992, Congress focused its efforts on promoting further reductions of U.S. HEU exports through the enactment of the Schumer Amendment to the Energy Policy Act. This conditioned exports of U.S.-origin HEU on the following criteria: (1) that there was no existing alternative LEU fuel for the reactor in question; (2) that the facility agreed to convert to LEU fuel as soon as it became available; and (3) that the United States was actively developing an alternative LEU fuel suitable for that facility.[31] This amendment led to a large reduction in United States HEU exports.

By 1996, the United States had exported approximately 25.6 metric tons of HEU, containing 18.6 metric tons of U-235. These exports were provided for civil applications, including as fuel for research reactors and as targets for the production of medical isotopes.[32] Almost all of this material was transferred to the Euratom countries, as well as Canada and Japan.[33] As exports of HEU continued to expand, a framework for ensuring the peaceful application of these materials lagged behind. Exports did decline considerably in the 1980's and continued on a downward trend until 1995-96, when no HEU was exported.[34] Nevertheless, HEU exports have since resumed, as the 2005 Burr Amendment allowed the United States to provide HEU to medical isotope producers in Europe and Canada without requiring them to agree to convert to an LEU-based production process.[35]

The Burr Amendment resulted from concerns in the U.S. Congress that the Schumer Amendment would endanger supplies of Mo-99 to the United States. Furthermore, MDS Nordion, the Canadian radioisotope producer, lobbied Congress to enact an exemption to the Schumer Amendment that would allow the United States to export HEU for use at Canada's NRU reactor. This change in energy policy has had a significant impact on the United States' international credibility in calling for the conversion of reactor fuels.

Continuing HEU Use

HEU continues to be used in the United States for both military and civilian purposes. Its utilization for naval propulsion is particularly widespread, and the United States is said to have reserved 128 metric tons of excess weapons HEU for naval and other reactor fuels.[36] The navy's current annual HEU consumption levels are said to be in the range of two metric tons.[37] As the United States no longer produces weapons-grade HEU, its supply for naval reactors will come from dismantled weapons and existing inventories.[38]

Radioisotope production
A 2009 report from the National Academy of Sciences titled "Medical Isotope Production Without Highly Enriched Uranium," stated that although there are not currently enough medical isotopes produced from LEU targets to meet U.S. domestic demand, there are "no technical reasons that adequate quantities cannot be produced from LEU targets in the future."[39] The report also recommended that DoE consider sharing conversion related R&D costs with existing customers to help alleviate some of the financial burden, as well as finding other means for incentivizing domestic production of Mo99.[40] Nevertheless, there are still some concerns in Washington over the expansion of domestic Mo-99 production. These concerns focus primarily on waste disposal, environmental reviews, and the licensing of new facilities.

Although the United States does not currently produce the medical isotope molybdenum-99, there has been an increase in calls for the establishment of a domestic production capability. The United States relies on foreign suppliers such as Nordion of Canada, but an unexpected shutdown at Canada's NRU reactor in May 2009—to repair a heavy water leak—led to concerns over the reliability of the supply.[41] As a result, legislation titled "The American Medical Isotopes Production Act" passed the U.S. House of Representatives in November 2009, but then-Senator Christopher Bond of Missouri prevented its consideration by the full Senate. The Act aimed to promote the production of Mo-99 in the United States, and to provide incentives for using LEU-based medical isotopes.[42] Such incentives would have been provided in three ways: (1) the legislation would have authorized $163 million over five years to encourage LEU-based production; (2) it would have subsidized the construction of facilities that used LEU in the production of Mo-99; and (3) it would have relieved the financial and legal burden of waste disposal for operators by authorizing the government to retain responsibility for final waste disposition.[43] With such incentives in place, the United States might have been in a position to produce double the U.S. demand for medical isotopes within seven years. The legislation called for ending exports of HEU to foreign producers of Mo-99 within seven years, with a possible extension of another six years if the Secretary of Energy concluded there was insufficient international supply of Mo99 (produced using LEU), to satisfy U.S. domestic demand.[44] Similar legislation was reintroduced in the Senate in 2011 after the seating of a new Congress, and has been approved by the Senate Energy and Commerce Committee.

Fuel Return

From 1958 to 1996 the United States accepted 6.9 metric tons of uranium from foreign countries containing 4.9 metric tons of U-235. The majority of this was U.S-origin, and was received in the form of spent nuclear fuel from Euratom countries, as well as Canada, Japan, and South Africa. The terms of the Atoms for Peace program allowed for the return of highly enriched spent fuel for reprocessing in the United States, and the first shipment of irradiated reactor fuel was received at the Idaho Chemical Processing Plant in July 1953.[45]

In 1986, the United States suspended the return of U.S.-origin spent nuclear fuel from foreign research reactors, but this policy was revised in 1996 when the DoE unveiled the Foreign Research Reactor Spent Nuclear Fuel (FRR SNF) Acceptance Program. Its intention was to recover as much U.S.-origin HEU as possible while assisting foreign research reactor operators with their conversion to LEU.[46]

HEU Facilities

It is estimated that 88 percent of the United States' HEU inventory is located at both the Y-12 Plant in Oak Ridge, Tennessee and the Pantex Plant in Amarillo, Texas. This material is held primarily in the form of active U.S weaponry, dismantled weapon parts, and reactors for the Naval Nuclear Propulsion Program.[47] Both plants are involved in the assembling and dismantlement of weapons, as well as in providing maintenance and technical upgrades to the stockpile.

In addition to being the storage site for the naval HEU stockpile, the Y-12 National Security Complex is also the main storage site for civilian HEU.[48] A recently constructed Highly Enriched Uranium Storage Facility at the Y-12 complex will consolidate most civilian HEU holdings, and will accept HEU from other sites, including that repatriated from abroad.[49] HEU is also stored in smaller quantities at several government laboratories, including Los Alamos National Laboratory, Idaho National Engineering and Environmental Laboratory, and Oak Ridge National Laboratory.[50]

The Reduced Enrichment for Research and Test Reactors (RERTR) Program and the Global Threat Reduction Initiative (GTRI)

The administrations of U.S. presidents Gerald Ford and Jimmy Carter first began to struggle with the problem of HEU minimization, leading to the establishment of the RERTR program. The aim of the program was to develop the technical means to utilize LEU instead of HEU in research reactors, while ensuring no significant loss of performance.[51] As substitute fuels were developed, existing reactors would be converted.

The RERTR program was reinvigorated in the aftermath of the terrorist attacks of 11 September 2001, as the United States became increasingly concerned about the security risks posed by the HEU held at research and test reactors around the globe. As a result, the United States placed greater emphasis on converting all research reactors to LEU fuel as soon as it was technically and politically viable to do so.[52] In 2003, the RERTR program submitted a plan to convert all Soviet- and U.S.-designed research reactors within a decade. In order to effectively implement this plan the program received increased funding, and was reorganized in May 2004 as the Global Threat Reduction Initiative (GTRI). GTRI consolidated all of the disparate elements involved in HEU minimization, and led an acceleration of worldwide reactor conversions.[53]

Conversion and Shutdown of HEU-Fueled Reactors and Reactor Projects

At the 2010 Nuclear Security Summit the United States indicated it had completed the conversion of all 20 of its domestic nuclear research reactors that could be converted without the development of new fuels.[54] This left a further six HEU-fueled reactors that the U.S. government said it will convert once an acceptable LEU-based fuel becomes available. Today there are only two non-governmental reactors that continue to run on HEU: the MITR reactor at the Massachusetts Institute of Technology, and the MURR reactor at Missouri University. Converting these two reactors requires the development of a new high-density uranium-molybdenum fuel—currently under development—to sustain the reactors' high neutron flux. The DoE originally hoped to convert the reactors by 2014, but this date now appears unlikely to be met.[55] The most recent U.S. reactors were converted in 2009 at the University of Wisconsin Research Reactor, and the Neutron Radiography Reactor at the Idaho National Laboratory. Conversion of the University of Wisconsin Research Reactor completed, two years ahead of schedule, the implementation of the North American Security and Prosperity Partnership (NASPP) of 2005. [56] Under the NASPP the United States, Mexico and Canada agreed to convert all civil HEU reactors on the North American continent by 2011 (where appropriate LEU fuel is available).

U.S. university-based research reactors converted since May 2004.

In addition to university-based research reactors, there are also a number of government owned reactors that continue to utilize HEU fuels.

Following a 2009 study by the National Academy of Sciences, five additional U.S.-based reactors and critical assemblies were added to the scope of the GTRI program.[57]

The post 9/11 era has witnessed an intensification of U.S. efforts to convert reactors both in the United States and abroad. This has been driven by the political emphasis placed on the threat posed by the continued civil use of HEU. In 2005, as part of the Bratislava Joint Statement on Nuclear Security Cooperation, the United States and Russia agreed to cooperate in the conversion of more than thirty U.S. and Russian- supplied research reactors across the globe.[58] Moreover, in March 2005, the United States, Mexico and Canada launched the Security and Prosperity Partnership of North America, in which they agreed to convert all civilian reactors to LEU fuel by 2011.[59] These conversions rely heavily, however, on the DoE's ability to develop and provide viable alternative fuels.

Policy Issues

Although the United States has spearheaded the reduction of HEU use in civil applications, primarily through the RERTR program, U.S. energy policy has also proved contradictory. Its original intention to maintain the nuclear monopoly following the end of World War II soon gave way to the 1953 Atoms for Peace Program, and by the early 1970's HEU exports from the United States averaged approximately 1,200 kilograms per year.[60]

Since its initiation in 1978, the RERTR program has been the driving force behind HEU minimization in spite of frequent policy drifts and funding cuts.[61] In the 1980s and 1990's, the program became marginalized as a result of interagency battles between the DoE and the Arms Control and Disarmament Agency (ACDA), but consolidation of all HEU minimization programs under the umbrella of the GTRI in 2004 provided greater direction to the program.[62]

Washington has attempted to set an example for HEU minimization by converting a number of its domestic research reactors. It is also in the process of developing appropriate LEU fuel that will enable its remaining civil research reactors to be converted in the near future. In addition, legislation currently sitting before the U.S. Senate concerning the establishment of a domestic Mo-99 production capability - and restrictions on exports of HEU — will, if passed, constitute another step towards eliminating civil use of HEU in the United States.

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[1] "Global Fissile Material Report 2010," The International Panel on Fissile Materials, 2010, p. 9, www.fissilematerials.org.
[2] "Highly Enriched Uranium Inventory: Amounts of Highly Enriched Uranium in the United States," U.S. Department of Energy, January 2006, www.doe.gov.
[3] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001.
[4] "Highly Enriched Uranium Inventory: Amounts of Highly Enriched Uranium in the United States," U.S. Department of Energy, January 2006, www.doe.gov.
[5] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 41.
[6] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 45.
[7] Steven Aftergood and Frank N. von Hippel, "The U.S. Highly Enriched Uranium Declaration: Transparency Deferred but not Denied," The Nonproliferation Review, Vol. 14, No. 1, March 2007, p. 154.
[8] "Highly Enriched Uranium Inventory: Amounts of Highly Enriched Uranium in the United States," U.S. Department of Energy, January 2006, p. 7, www.doe.gov.
[9] "Highly Enriched Uranium Inventory: Amounts of Highly Enriched Uranium in the United States," U.S. Department of Energy, January 2006, p. 7, www.doe.gov.
[10] Figure drawn from comparing "Highly Enriched Uranium Inventory: Amounts of Highly Enriched Uranium in the United States," U.S. Department of Energy, January 2006, p. 9, www.doe.gov, and "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 102.
[11] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 102.
[12] Sharon Squassoni, Andrew Demkee, and Jill Marie Parillo, "Banning Fissile Material Production for Nuclear Weapons: Prospects for a Treaty (FMCT)," CRS Report for Congress, 14 July 2006, p. 4.
[13] Ole Reistad and Styrkaar Hustveit, "HEU Fuel Cycle Inventories and Progress on Global Minimization," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 274; and Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 165.
[14] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 37.
[15] "Global Fissile Material Report 2007: Second Report of the International Panel on Fissile Materials," International Panel on Fissile Materials, 2007, p. 19, www.fissilematerials.org.
[16] "Global Fissile Material Report 2010," The International Panel on Fissile Materials, 2010, p. 16, www.fissilematerials.org.
[17] Steven Aftergood and Frank N. von Hippel, "The U.S. Highly Enriched Uranium Declaration: Transparency Deferred but not Denied," The Nonproliferation Review, Vol. 14, No. 1, March 2007, p. 155.
[18] O Bukharin, "U.S.-Russian Bilateral Transparency Regime to Verify Nonproduction of HEU," Science and Global Security, No. 10, 2002, p. 211.
[19] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 51.
[20] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 51.
[21] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 26.
[22] "Overview: Paducah Gaseous Diffusion Plant," United States Nuclear Regulatory Commission, May 2009, www.nrc.gov.
[23] "Fact Sheet on Uranium Enrichment," United States Nuclear Regulatory Commission, May 2009, www.nrc.gov.
[24] "Global Fissile Material Report 2010," The International Panel on Fissile Materials, 2010, p. 17, www.fissilematerials.org.
[25] "Global Fissile Material Report 2010," The International Panel on Fissile Materials, 2010, p. 16, www.fissilematerials.org.
[26] "Global Fissile Material Report 2010," The International Panel on Fissile Materials, 2010, www.fissilematerials.org, p. 16.
[27] "Global Fissile Material Report 2010," The International Panel on Fissile Materials, 2010, www.fissilematerials.org, p. 16.
[28] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 161.
[29] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 161.
[30] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 162.
[31] DOE, Highly Enriched Uranium: Striking a Balance, A Historical report on the United States Highly Enriched Uranium production, Acquisition and Utilization Activities from 1945 through September 30, 1996 (Washington, DC: Department of Energy, 2001), p. 96.
[32] "U.S. Needs Stronger Export Controls on Highly Enriched Uranium," Union of Concerned Scientists, 21 November 2008, www.ucsusa.org.
[33] DOE, Highly Enriched Uranium: Striking a Balance, A Historical report on the United States Highly Enriched Uranium production, Acquisition and Utilization Activities from 1945 through September 30, 1996 (Washington, DC: Department of Energy, 2001), p. 96.
[34] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 164.
[35] Cristina Hansell, "Nuclear Medicine's Double Standard," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 197.
[36] Ole Reistad and Styrkaar Hustveit, "HEU Fuel Cycle Inventories and Progress on Global Minimization," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 275.
[37] Ole Reistad and Styrkaar Hustveit, "HEU Fuel Cycle Inventories and Progress on Global Minimization," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 279.
[38] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 42.
[39] Medical Isotope Production Without Highly Enriched Uranium, National Academy of Sciences, 2009, p. 2.
[40] Medical Isotope Production without Highly Enriched Uranium, National Academy of Sciences, 2009, p. 3. It should also be noted that South Africa announced at the 2010 Nuclear Security Summit that it had adopted a national policy of HEU-free production of medical isotopes, and had developed the technology to carry it out. As a result, South Africa is now exporting LEU-based Mo99 to the United States.
[41] "U.S. Needs Med Isotope Production Capability," Union of Concerned Scientists, 14 January 2009, www.ucsusa,org.
[42] Miles A. Pomper and William C. Potter, "Medical isotope production: The U.S. must follow South Africa's lead," Bulletin of the Atomic Scientists, 17 December 2010, www.thebulletin.org.
[43] Miles A. Pomper and William C. Potter, "Medical isotope production: The U.S. must follow South Africa's lead," Bulletin of the Atomic Scientists, 17 December 2010, www.thebulletin.org.
[44] "American Medical Isotopes Production Act of 2011," 25 January 2011, www.gpo.gov.
[45] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 69.
[46] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 19.
[47] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 37.
[48] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 172.
[49] "Y-12's Future," Y-12 National Security Complex, www.y12.doe.gov.
[50] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 94.
[51] Armando Travelli, R. Domagala, Jim Matos, J. Snelgrove, "Development and Transfer of Fuel Fabrication and Utilization Technology for Research Reactors," Paper presented at International Conference on Nuclear Technology Transfer, Buenos Aires, 1 November 1982.
[52] Armando Travelli, "Status and Progress of the RERTR Program in the Year 2002," Presentation at RERTR meeting, San Carlos de Bariloche, Argentina, 3-8 November 2002.
[53] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 168.
[54] "Nuclear Security Summit National Statement of the United States," The White House, 13 April 2010, www.whitehouse.gov.
[55] "Two More U.S. Reactors Stop Using Highly Enriched Uranium," Global Security Newswire, 28 September 2009; and Bryan Bender, "Terrorists Could Target Reactor; MIT Delays Conversion of Fuel," Boston Globe, 28 December 2009, www.boston.com.
[56] "NNSA converts two U.S. research reactors from HEU to LEU," Nuclear Engineering International, 28 September 2009, www.neimagazine.com.
[57] "Breakout of GTRI Reactor Conversion Expansion," U.S. Department of Energy, Presentation at RERTR 2009, November 2009.
[58] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 168.
[59] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 169.
[60] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 159.
[61] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 175.
[62] Anya Loukianova and Cristina Hansell, "Leveraging U.S. Policy for a Global Commitment to HEU Elimination," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 164.