As the first country to harness the power of the atom, the United States was also the first to enrich uranium. Although it ended all Highly Enriched Uranium (HEU) production in 1992, today the United States continues to use HEU for military and civilian purposes, and to engage in HEU commerce. [1] However, Washington has made considerable progress towards eliminating HEU use in civilian applications. Its initiatives have included conversions and shutdowns of research reactors at home and abroad, and the development of HEU-free medical isotope production. The United States has also led diplomatic efforts, most recently during the 2010 and 2012 Nuclear Security Summits, aimed at phasing out the civilian use of HEU around the world.

Overview of United States HEU Holdings

Two reports from the United States Department of Energy (DOE) provide the most complete official record of U.S. HEU Stocks. In 1996, DOE issued "Highly Enriched Uranium: Striking a Balance," a comprehensive public declaration of U.S. civilian and military HEU holdings.[2] DOE subsequently updated this report in 2006 with a study titled "Highly Enriched Uranium Inventory” (these documents are hereafter referred to as the "DOE HEU Reports").[3]

The DOE HEU Reports provide snapshots of official accounting of the U.S. HEU stockpile. Between 1945 and 1996, the United States produced 1,045.4 metric tons of HEU, which contained 859.2 metric tons of uranium-235 (U-235).[4] In addition, the United States acquired 3.1 metric tons from downblending and received 6.9 metric tons from foreign countries.[5] The 1996 report stated that as of 30 September 1996, the United States had 740.7 metric tons of HEU, containing 620.3 metric tons of U-235 (U-235).[6] In turn, the 2006 report indicated that as of 30 September 2004, the total U.S. HEU inventory was 686.6 metric tons, containing 590.5 metric tons of U-235. [7] This total number included materials in military and civilian use, as well as materials declared as excess to weapons use. The HEU materials in waste were not reported.

In 1994, Washington declared 174 tons of HEU to be excess to weapons use. Of these, all but 18 tons of HEU (naval reactor spent fuel), were slated for downblending to Low Enriched Uranium (LEU). In 2005, an additional 200 tons were declared excess. Of these, 20 tons were set aside for research and space reactors, while another 20 tons were to be blended down for LEU fuel. The remaining 160 tons were reserved for naval fuel, but eventually 31 tons of these were found unsuitable and instead will be blended down. Another 10 tons were in domestic and foreign research reactor spent fuel. [8]

The International Panel on Fissile Materials (IPFM) estimated the total U.S. stockpile of HEU to be 610 metric tons as of mid-2011.[9] This number included 260 metric tons of HEU available for weapons use, 230 metric tons for naval reactor fuel (100 of them irradiated), 20 metric tons in civilian use, and 100 metric tons declared excess and set aside for downblending or disposal.[10] In addition, over 135 metric tons were undergoing downblending.[11] These figures also include U.S.-origin HEU that was repatriated from third countries as part of threat reduction efforts.

Military HEU

Despite ceasing the production of HEU for use in weapons in 1964, the United States continued to produce the material for use in naval reactors until 1992. [12] Today, the Department of Defense (DOD) continues to utilize existing HEU stocks in nuclear warheads as well as in naval nuclear propulsion, programs managed jointly with DOE. These stocks are located at the DOE’s Y-12 Plant in Oak Ridge, Tennessee; the Pantex Plant near Amarillo, Texas; and in locations under DOD custody.[13]

The IPFM estimated that the United States had approximately 260 metric tons of HEU designated for possible use in weapons as of mid-2011.[14] At present, there are “approximately 5,000” total nuclear warheads in the U.S. nuclear arsenal. [15] Of this total, about 2,150 warheads are operational.[16] In addition, 130 metric tons of HEU were set aside to power the U.S. Navy’s aircraft carries, cruisers, destroyers, and submarines, while 100 metric tons of HEU were in irradiated nuclear reactor fuel.[17] To date, there has been little U.S. government consideration of the possibility of converting these naval reactors to LEU use.[18]

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 IPFM estimated that in 2011 the United States possessed approximately 20 metric tons of civilian HEU.[19]

HEU Production

Prior to the halt of all U.S. HEU production in 1992, the material was produced at several facilities across the United States. These included the Y-12 Plant (which used electromagnetic separation), and the Oak Ridge Gaseous Diffusion Plant (K-25), both near Oak Ridge, Tennessee, and the Portsmouth Gaseous Diffusion Plant near Portsmouth Ohio. [20] The latter facility was the largest producer of HEU with a total of 552.2 metric tons of HEU containing 509.2 metric tons of U-235, all produced between 1956 and 1992. [21] Furthermore, although no HEU was produced at the Paducah Gaseous Diffusion Plant near Paducah, Kentucky, until 1960 the facility produced LEU feedstock that was subsequently further enriched at the sites in Oak Ridge and Portsmouth. [22]

The Energy Policy Act of 1992 created the United States Enrichment Corporation (USEC), a commercial entity tasked with enrichment of LEU fuel and the management of sites, excluding Oak Ridge, which formerly produced HEU. Beginning in 1993, USEC also facilitated the implementation of the U.S.-Russian Megatons to Megawatts program that carried out the conversion of HEU from Russia’s dismantled nuclear weapons into LEU to fuel U.S. power plants. When this program ends in 2013, it will have recycled 500 metric tons (MT) of Russian HEU, the equivalent of approximately 20,000 warheads.[23]

At present, USEC operates the Paducah Plant that produces LEU fuel. The Portsmouth Plant site hosts the American Centrifuge Project, a USEC advanced gas centrifuge technology effort. Currently at the research, development, and demonstration phase, this project has experienced funding difficulties and delays and is expected to be ready for commercial deployment no earlier than 2014.[24] In turn, the Oak Ridge Gaseous Diffusion Plant is undergoing decontamination and decommissioning.[25]

Several other private companies are currently standing up LEU production ventures in the United States. These include a URENCO plant in New Mexico and an Areva facility in Idaho.[26] Further, GE/Hitachi is developing a test facility for its laser enrichment technology known as Separation of Isotopes by Laser Excitation (SILEX) in North Carolina. In the United States, several groups have expressed concern about the proliferation potential of the SILEX technology, which has a much smaller footprint than centrifuge-based enrichment technologies, and could thus be easily hidden. [27]

HEU Commerce

After the end of World War II the U.S. Congress passed the Atomic Energy Act of 1946 (the McMahon Act), which sought to maintain the U.S. nuclear monopoly. However, President Dwight D. Eisenhower's 1953 Atoms for Peace initiative clashed with some of the Act's core objectives. Under Atoms for Peace, an effort to promote nuclear science and the use of nuclear technology worldwide, the United States provided assistance to states that agreed to forego the development of nuclear weapons.

A 1954 amendment to the Atomic Energy Act allowed for bilateral nuclear agreements with friends and allies (known as "123 Agreements," named for the relevant section of the Act).[28] These agreements initially only envisioned the export of LEU fuel. Soon, however, new high-powered research and test reactors that required low density uranium fuels enriched to 90-93% were constructed abroad. As a result, in the mid-1960s the United States began to export HEU fuel for their use.[29]

Triggered by Congressional concerns about India's nuclear test, the 1978 Nuclear Non-Proliferation Act amended the Atomic Energy Act by establishing a requirement for full-scope safeguards in the recipient country as a condition for all U.S. nuclear exports. That same year, 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, led by Argonne National Laboratory. RERTR, now a part of the Global Threat Reduction Initiative (GTRI), is an effort to design and qualify appropriate LEU fuel substitutes, and to convert research and test reactors in the United States and abroad from HEU to suitable LEU fuel so that these facilities will no longer require U.S.-origin HEU fuel.[30]

In 1992, Congress focused its efforts on further restricting U.S. exports of HEU through the passage of the Schumer Amendment to the Energy Policy Act. This legislation 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]

According to the 1996 DOE HEU Report, the United States through 1996 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] This material was transferred largely to the Euratom countries, Canada, and Japan. The exports declined considerably in the 1980's and, after the passage of the Schumer Amendment, continued on a downward trend until 1996, when no HEU was exported.[33]

In 2005, this decline was reversed when the Burr Amendment to the National Energy Policy Act allowed the United States to license the export of HEU to several states without a requirement to convert their research reactors to an LEU-based production process. The amendment reflected Congressional concerns about the supply vulnerabilities of a critical medical isotope called Molybdenum-99 (Mo-99). MDS Nordion, the Canadian radioisotope producer, reportedly also lobbied for an exemption to the Schumer Amendment that would allow the United States to export HEU for use at Canada's NRU reactor. [34]

Since the passage of the Amendment, the United States has continued to export HEU abroad for the production of Mo-99. Between 2005 and 2012, the Nuclear Regulatory Commission licensed over a dozen export transactions to France, Belgium, and Canada for use as target material and reactor fuel.[35] For example, the United States shipped 186.4 kilograms of HEU with 174 kilograms of U-235 to France in April 2012.[36] However, at the March 2012 Nuclear Security Summit in Seoul, Belgium, France, and the Netherlands committed to convert their Mo-99 production to LEU by 2015. In light of these commitments, the United States promised to supply "the necessary HEU target material to ensure uninterrupted production of medical isotopes" to these states up to their conversion deadline.[37]

Continuing HEU Use

Despite gradually reducing and downblending its stocks, the United States continues to use HEU for military and civilian purposes. Nuclear weapons and naval propulsion are likely to remain major reasons for retaining a dedicated stockpile of the material in the near future.

The most immediate challenge for U.S. policy lies in its treatment of HEU in civilian applications. Despite continuing to export HEU for the production of medical isotopes, the DOE’s National Nuclear Security Administration (NNSA) has developed several approaches to incentivizing HEU-free production of medical isotopes at home and abroad. Washington has also made a concerted effort to repatriate U.S.-origin and Soviet-origin materials from third countries, and to convert and shut down research and test reactors worldwide.

Radioisotope Production

Though the patients in its hospitals provide the world's biggest market for medical isotopes, the United States has no domestic Mo-99 production capability at this time. [38] There are currently seven major reactors producing Mo-99 worldwide. These include four in Europe (BR-2 in Belgium, HFR in Netherlands, OSIRIS in France, and MARIA in Poland), and three in other parts of the world (the NRU in Canada, SAFARI in South Africa, and OPAL in Australia). Because of this geographic distribution and the isotope's extremely short shelf life, the reliability of Mo-99 supply is a delicate issue.[39] The reactors in Europe and Canada are either powered by HEU fuel, use the material in irradiation targets for producing medical isotopes, or both. While reactor fuel conversion efforts have made significant progress, the process of moving to LEU targets has been considerably slower, in part because such changes require both reactor operators and processing companies to initiate changes.

Since 2005, the reliability of the suppliers using HEU for isotope production has been repeatedly called into question. The most vivid example has been Canada's NRU reactor, which has traditionally provided the majority of isotopes for the U.S. market. In 2007 and 2009, as discussed in Canada's HEU profile, this reactor was repeatedly shut down for prolonged periods of time. In 2009, its shutdown coincided with a maintenance shutdown at the HFR reactor in the Netherlands, the second largest supplier of isotopes for the U.S market. These events triggered repeated shortages of Mo-99 in the United States.[40]

In 2007, the National Academy of Sciences began a study that examined the conflicting goals of reducing exports of U.S.-origin HEU (the Schumer Amendment), and assuring the reliability of the Mo-99 supply (the Burr Amendment). In 2009, the NAS report concluded that there were "no technical reasons that adequate quantities cannot be produced from LEU targets in the future."[41] The report recommended that DOE consider sharing conversion-related research and development costs with existing customers to help alleviate some of the financial burden, and also suggested finding other means for incentivizing domestic LEU-based production of Mo-99.[42]

Since then, the NNSA has sought to increase the supply of LEU-based isotopes on the U.S. market. In 2010, the NNSA announced that a consortium of producers from South Africa and Australia would begin to supply LEU-based Mo-99 to the United States. This consortium has, at times, supplied as much as a third of the Mo-99 market for diagnostic procedures in the United States.[43] In addition, the NNSA has worked with the IAEA to develop small-scale regional production capabilities in Eastern Europe, Latin America, and elsewhere. In turn, European Mo-99 producers have pledged to convert their facilities to LEU use by 2015.[44]

The NNSA has also pursued the development of an indigenous medical isotope production capability. Following the NAS report's recommendations, it concluded cooperative agreements with several U.S. companies to explore alternative methods of Mo-99 production (e.g., methods that would not involve the irradiation of targets in research reactors).[45] However, issues such as waste disposal, environmental reviews, and the licensing of new facilities remain causes for concern.

Establishing a reliable supply of LEU-based medical isotopes has also proven difficult because the production of Mo-99 with HEU is presently cheaper. The LEU production process is only slightly more expensive than its HEU counterpart. However, HEU producers generally face low capital costs because they use old facilities constructed with government financing. This means that, when passed on to the consumer, the cost of the HEU-based product is lower. This concern grew in 2010 after Canada's MDS Nordion, the company that currently produces Mo-99 using the NRU reactor, announced that it would start a joint venture that would use Russian HEU to produce Mo-99 for the U.S. market. The NRU reactor is scheduled to shut down in 2016.

U.S. policy has increasingly aimed to level the playing field for new LEU-based producers.[46] In June 2012, the White House announced that it was committed to eliminating the use of HEU in the production of medical isotopes, while also assuring supply reliability. In order to achieve both of these goals, official U.S. policy would encourage the purchase of HEU-free Mo-99 at home and abroad. According to the White House release, policy steps would include the following:

In regard to health insurance payment options, in July 2012 the White House unveiled a proposed Health and Human Services department regulation that would incentivize hospitals and medical facilities to use LEU-based isotopes. It would do so by using the Medicare and Medicaid systems to pay an additional $10 each time Mo-99 produced without HEU was used for diagnostics on Medicare and Medicaid patients. The White House has encouraged the OECD's Nuclear Energy Agency to examine additional incentives for LEU-based medical isotope production. [48]

Meanwhile, despite broad support in both houses of Congress to take steps to encourage LEU-based production, lawmakers have yet to pass final legislation on the subject. In November 2009 a bill titled "The American Medical Isotopes Production Act" passed the U.S. House of Representatives. 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 Mo-99 (produced using LEU), to satisfy U.S. domestic demand. The Act aimed to promote the production of Mo-99 in the United States, and to provide incentives for using LEU-based medical isotopes. The 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. However, this bill was not considered by the full Senate because of an intervention by then-Senator Christopher Bond of Missouri.[49]

A bill containing similar language (S.99) was reintroduced in the Senate in 2011. The Senate passed the legislation in November 2011. The bill is currently awaiting consideration by the House of Representatives. [50] Its fate, however, is unclear.

In May 2011 U.S. representatives Edward Markey and Jeff Fortenberry expressed concerns, in a letter to the DOE, regarding the possibility of Nordion using Russian HEU for the development of Mo-99 for the U.S. market. A January 2012 letter to these lawmakers signed by public health and nuclear experts called on Congress to enact a "preferential procurement" clause. This letter noted that there were several options that would enable "preferential procurement": "One option, given that domestic producers will avoid HEU, would be to legislate that the United States must halt the import of HEU-based versions of these isotopes when a sufficient supply of the alternatives is available. Another option would be to require U.S. health authorities to terminate authorization for use of HEU- based versions when a sufficient supply of the alternatives is available. A third option would be to impose a tax on HEU-based versions of these isotopes, channeling any resulting revenue to support production without HEU."[51] But during an election year, it remains unclear whether this issue will gain sufficient traction in Congress.

Fuel Return
 
Between 1958 and 1986, the United States accepted 6.9 metric tons of uranium from foreign countries containing 4.9 metric tons of U-235.[52] The majority of this was U.S-origin material, received in the form of spent nuclear fuel from Euratom countries, 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 Idaho Chemical Processing Plant received the first shipment of irradiated reactor fuel in July 1953.[53]

In 1986 the United States suspended the return of U.S.-origin spent nuclear fuel from foreign research reactors, but revised this policy 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 LEU conversion. Another initiative, the Gap Materials Program, was soon also created to address vulnerable, high-risk nuclear and radiological materials throughout the world that were not addressed under other existing programs (i.e., materials that were neither U.S. nor Russian-origin). [54] Both programs were subsequently folded into the GTRI program.

The FRR SNF has actively repatriated U.S.-origin HEU fuel since 1996. As of March 2012 58 shipments had been completed (with a total of 9,261 fuel assemblies), and with 30 countries participating. Of these shipments, 45 consisted of aluminum-based spent nuclear fuel and were placed into storage at the Savannah River Site in South Carolina, 4 consisted of fresh or slightly irradiated fuel and were thus sent to the Y-12 National Security Complex, and the remaining 8 consisted of TRIGA-type fuel and were stored at Idaho National Laboratory. [55] By 2013 GTRI plans to complete its total repatriation goal of 1,364 kilograms of HEU (with approximately 1,300 kilograms already removed). GTRI also plans to accept 911 kg of Gap materials by 2016 (252 kg as of late 2011). [56]

Conversion and Shutdown of Heu-Fueled Reactors and Reactor Projects

With the creation of the RERTR program in 1978, the United States began to make technical progress toward the conversion of research and test reactors. Six years after the program started, the Ford Nuclear Reactor at the University of Michigan, and the Osiris experimental reactor at France's Saclay Nuclear Research Center had been converted. During the 1980s, RERTR efforts were marginalized by the Department of Energy and Congress, and the program's funding was consistently problematic. Further, the United States backtracked on conversion efforts when it initiated the development of the Advanced Neutron Source, a research and test reactor that would be powered by HEU (the construction of this reactor was subsequently cancelled). [57]

Political developments in the early 1990s and 2000s brought a focus to fissile materials security. When the Soviet Union dissolved, U.S. policymakers became concerned about the security of materials on its territory, initiating cooperative threat reduction projects that also included the repatriation of HEU materials. Also in the 1990s, U.S. and Russian officials began to pursue research and test reactor conversion efforts cooperatively.[58] The RERTR program was further 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, all U.S. civil HEU minimization efforts were reorganized into the Global Threat Reduction Initiative (GTRI) in 2004. [59]

Since 2004, GTRI efforts have converted seven research and test reactors and shut down two reactors in the United States. The conversions represent a reduction of nearly 40 kilograms of HEU use. In turn, the shutdowns represent the elimination of approximately 3,000 kilograms of annual HEU use (See U.S. HEU tables). [60]

Six high performance research reactors, requiring the development and fabrication of a high density Uranium-Molybdenum (U-Mo) fuel, remain to be converted. These include the reactors at the Massachusetts Institute of Technology, the University of Missouri, the National Institute of Standards and Technology (NIST), the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL), and its associated critical assembly (ATRC). [61] The MIT reactor is expected to be the first reactor converted after the U-Mo fuel is qualified and licensed by the NRC.

Policy Issues

Over the last several decades, the United States has led international initiatives to convert research and test reactors, repatriate HEU fuel worldwide, and develop HEU-free medical isotope production capabilities. As further discussed in other sections of the NTI Civilian HEU Collection, efforts such as the Nuclear Security Summits have focused the world's attention on nuclear security problems, and especially the challenges posed by HEU in civilian applications. Since 2010 the Summits have formed an important mechanism for drawing high-level attention to the issue of fissile material security, facilitating information sharing and providing an incentive for states to follow through on their commitments. Despite Washington's leadership, however, several additional challenges remain for U.S. HEU policy.

During the last several decades, the United States has made great strides in promoting fissile material transparency. The release of two DOE Reports on HEU, combined with the reports on Plutonium production, offers lessons in leadership by example. Whether another excess materials declaration by Washington would be able to convince Moscow to respond in kind remains an open question. Some have argued that the United States should be able to declare more HEU excess to its defense needs as it dismantles weapons in its arsenal and considers the needs of the naval propulsion program.[62] However, another excess declaration poses the question of how much material should go to naval and other uses as opposed to the commercial market, an issue where there is no consensus option between reactor operators and commercial fuel providers. Furthermore, the downblending of the HEU already declared excess to weapons needs would take until 2050 if it proceeds at the current rate of 3-4 tons per year. This is due to the slow speed of warhead component dismantlement.[63]

While the executive branch has been aggressive in its efforts to reduce the use of HEU for medical isotope production, the lack of Congressional attention to this issue has undermined the efforts of the White House. The legislature, traditionally a supporter of fissile materials security, has been unable to pass legislation that would solidify a domestic consensus on civil HEU minimization. Instead, Congressional policy from 2005 until recently had the effect of promoting an increase in U.S. exports of HEU.

Another challenge has been the use of HEU for naval propulsion. To date, the U.S. Navy has not seriously considered the conversion of its reactors to LEU. This arguably undermines U.S. leadership on nonproliferation because it comes at a time when India is moving forward on nuclear propulsion, and Iran is also declaring interest in the technology.

As this collection's article on the International Politics of Civilian HEU Elimination discusses in greater detail, the United States has played a central role in diplomatic efforts aimed at minimizing the civilian use of HEU. The Nuclear Security Summit process has successfully accelerated the "lockdown" of vulnerable materials. However, only the successful conclusion of a Fissile Material Cutoff Treaty (FMCT) would provide a binding international fissile material regime.

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[13] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 4.
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[15] Hans M. Kristensen and Robert S. Norris, "U.S. Nuclear Forces, 2012," Bulletin of the Atomic Scientists, May/June 2012, vol. 68/no. 3, pp. 84-91.
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[18] Cole J. Harvey, "At Sea Over Naval HEU: Expanding Interest in Nuclear Propulsion Poses Proliferation Challenges," Nuclear Threat Initiative Issue Brief, November 29, 2010, www.nti.org
[19] For a discussion of the countries that choose to list their holdings, see Cristina Chuen, "Developing HEU Guidelines," paper presented at the 2007 International RERTR Meeting in Prague, 2007, www.rertr.anl.gov.
[20] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 54-67.
[21] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 2001, p. 64.
[22] "The Paducah Gaseous Diffusion Plant," United States Enrichment Corporation website, accessed July 27, 2012, www.usec.com.
[23] "Megatons to Megawatts," the United States Enrichment Corporation website, accessed July 27, 2012, www.usec.com.
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[26] "U.S. Nuclear Power Policy," World Nuclear Association, April 2012, http://www.world-nuclear.org.
[27] Elaine M. Grossman, "Nonproliferation Advocate Asks NRC to Open Hearing on Laser Enrichment," National Journal, July 11, 2012, www.nationaljournal.com.
[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] "Highly Enriched Uranium: Striking a Balance," United States Department of Energy, January 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] 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.
[34] Cristina Hansell, "Nuclear Medicine's Double Standard," The Nonproliferation Review, Vol. 15, No. 2, July 2008, p. 197.
[35] Written statement of Margaret M. Doane, director of the office of international programs, United States Nuclear Regulatory Commission to the Senate Committee on Energy and Natural Resources on the American Medical Isotope Production Act of 2011, January 2011, pbadupws.nrc.gov.
[36] Pavel Podvig, "U.S. Reported to Complete HEU Shipment to France," International Panel on Fissile Materials blog, April 2, 2012, fissilematerials.org.
[37] "Belgium-France-Netherlands-United States Joint Statement: Minimization of HEU and the Reliable Supply of Medical Radioisotopes," State Department press release, March 26, 2012,www.state.gov.
[38] Cristina Hansell, "Nuclear Medicine's Double Standard," The Nonproliferation Review, Vol. 15, No. 2, July 2008.
[39] Miles Pomper, ""HEU Minimization after the Seoul Nuclear Security Summit," paper presented at the International Nuclear Materials Management conference in Orlando, Florida, July 2012.
[40] Medical Isotope Production without Highly Enriched Uranium, National Academy of Sciences, 2009, pp. 1-15.
[41] Medical Isotope Production Without Highly Enriched Uranium, National Academy of Sciences, 2009, p. 2.
[42] Medical Isotope Production without Highly Enriched Uranium, National Academy of Sciences, 2009, p. 3.
[43] "Record Levels of Non-HEU-Based Mo-99 Supplied to the United States," National Nuclear Security Administration press release, June 2, 2011, nnsa.energy.gov. It should be noted, however, that as of mid-2012, NECSA still supplies HEU-based Mo-99 to Europe because it is not yet licensed to supply LEU-based Mo-99 there.
[44] Miles Pomper, ""HEU Minimization after the Seoul Nuclear Security Summit," paper presented at the International Nuclear Materials Management conference in Orlando, Florida, July 2012.
[45] "NNSA Signs Cooperative Agreement to Support the Production of Molybdenum-99 in the United States Without the Use of Highly Enriched Uranium," National Nuclear Security Administration press release, May 8, 2012, nnsa.energy.gov.
[46] Miles Pomper, ""HEU Minimization after the Seoul Nuclear Security Summit," paper presented at the International Nuclear Materials Management conference in Orlando, Florida, July 2012.
[47] "Encouraging Reliable Supplies of Molybdenum-99 Produced without Highly Enriched Uranium," The White House Office of the Press Secretary, June 7, 2011, www.whitehouse.gov.
[48] Douglas P. Guarino, "U.S. Proposes Bigger Medicare Payouts to Avoid Bomb-Grade Uranium," Global Security Newswire, July 11, 2012, www.nti.org.
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