There are currently three principal uses of HEU (uranium with the proportion of the U-235 isotope over 20%), in the civilian nuclear sector: in research reactors; for medical isotope production; and as fuel in icebreaker propulsion reactors. Additionally, HEU has been used in space propulsion reactors and in nuclear power reactors. The two most widespread civil uses of HEU are as research reactor fuel and as targets for the production of medical isotopes. While many experts believe that these uses could be replaced with LEU or other alternatives, some countries may be reluctant to agree to further restrictions on civilian HEU that would limit their current activities.

Although there is no international agreement on banning the use of HEU in future research reactors, no new HEU-fueled civilian research reactors with a power level of more than 1 MW have been built in Western countries since the early 1980s, with the exception of Germany's FRM-II reactor. By contrast, seventeen new research reactors worldwide were built using LEU fuels.

HEU USE IN RESEARCH REACTORS

Research reactors are small fission reactors designed to produce neutrons for a variety of purposes, including scientific research, training, and medical isotope production. Significantly less powerful than commercial power reactors, research reactors use smaller amounts of uranium for neutron production. While many research reactors initially used low enriched uranium or LEU fuel (uranium with the proportion of the U-235 isotope under 20%), the LEU fuel technology used in the 1950s soon reached its limits. In order to improve the performance of the reactors with existing technology, and to enable more powerful reactors to be built, HEU fuel soon became the standard used by the vast majority of research reactors.

Because HEU fuels have a much greater proportion of the fissile isotope uranium-235 and a much lower proportion of the parasitic absorber uranium-238 than LEU fuels, HEU fuels could generate higher neutron flux.[1] A number of these reactors used fuel with a very high enrichment level, approximately 90% U-235, while many now use fuel enriched to approximately 36%. The amount of fuel the reactors require also varies dramatically, from just 1 kg in Miniature Neutron Source Reactors (MNSR), to approximately 10 kg per year in many pool reactors, to more than 100 kg per year in some of the most powerful reactors. Some of these reactors also have stocks of fresh and spent fuel on site, which makes them a potentially attractive target for thieves and terrorists seeking access to weapons-useable nuclear materials.

Since the late 1970s, programs to convert research reactors to LEU fuel have developed new fuels, reconfigured some reactors to minimize losses in neutron flux, and in some cases even increased the flux.[2] The United States, Russia, and a handful of other countries are working in cooperation to develop higher density LEU fuels that could substitute for HEU fuels in existing research reactors. Several types of replacement LEU fuels have been developed already. Uranium-silicide fuel developed in the 1980s has a uranium density sufficient to convert the vast majority of reactors. Uranium-molybdenum (U-Mo) fuels with very high uranium densities are currently under development and testing, and could potentially replace the HEU fuel in the remaining reactors. Once development of U-Mo fuel is complete, and it has been licensed and put into production, virtually all present and future civil research reactors can be converted to LEU. This new LEU fuel will offer "unprecedented performance" that exceeds what could historically be achieved with HEU.[3]

Pressure-Tube Test Reactors
While few in number, pressure tube reactors, used to test experimental fuel assemblies, are very powerful and can consume as much as 100 kilograms of fuel per year if run continuously. At the present time, there are three such reactors: in Russia (at the All-Russian Scientific Research Institute of Atomic Reactors in Dmitrovgrad); in Poland (at the Institute of Atomic Energy in Swierk), and in China (at the Southwest Reactor Engineering Research and Design Academy near Chengdu). The RERTR Program has been active in developing new fuels in order to make the conversion of these reactors possible.

Low-Powered Research Reactors
In addition to research and test reactors, there are also critical assemblies, subcritical assemblies, and pulse reactors that use fuels containing HEU. These types of reactors are much lower-powered than typical research and test reactors, and thus do not require the same type of cooling systems. This allows them to be reconfigured quickly with different fuel types, and makes possible a wide range of experimental work. Critical and subcritical assemblies, for example, are typically used for either basic physics experimentation or to model the properties of proposed reactor cores.[4] They often contain very large amounts of HEU, and in some cases they are used to mock-up the cores of large power reactors. Some experts, however, believe that such critical assemblies can now be replaced with computer simulations.[5]

Pulsed reactors, another type of specialized low-powered reactor, are used to produce short, intensive power and radiation impacts.[6] The neutron flux produced from the pulse is of much higher density than could be achieved in a reactor operating at a continuous state. Pulse reactors generally use large quantities of HEU fuel to achieve this high level of neutron flux, and could be difficult to convert from HEU to LEU fuel. However, these reactors are generally used for defense, not civilian, purposes and would thus not be covered by a civilian ban.[7] Some experts have suggested that these reactors, like critical assemblies, could be replaced with computer simulations.[8] Conversion to LEU of some reactors with pulsing capabilities, such as TRIGA reactors, is possible.

Low powered reactors pose unique proliferation challenges. Their low power means that they consume their fuel very slowly, so that they have what are termed "lifetime cores" in many cases. Existing facilities with these low power reactors thus have little economic incentive to convert to LEU, since they can continue to operate well into the future on current stocks of HEU. Furthermore, their fuel is not highly irradiated. As a result, the HEU fuel in these low power reactors, like that of many other research reactors, is potentially attractive to thieves because it is not highly radioactive.

There are currently over 239 research reactors in some 56 countries—including critical and subcritical assemblies as well as pulsed reactors—operating around the world, almost half of which use HEU as their primary fuel source.[9] (There is as yet no comprehensive, authoritative inventory of civil HEU globally, another obstacle to progress in this area.) The largest concentrations of these reactors are found in the former Soviet Union, the United States, and the European Union.

HEU USE FOR RADIOISOTOPE PRODUCTION

HEU continues to play a major role in the production of radioactive isotopes for medical applications. To produce one frequently used isotope, for example, HEU targets are irradiated in a reactor, producing the fission product molybdenum-99, which has a 2.7-day half-life and decays to 6-hour half-life technetium-99m, a gamma ray emitter used in medical imaging.[10]

Until recently, there were four major international producers of radioisotopes who used HEU: MDS Nordion (Canada); Mallinckrodt (Netherlands); Institute National des Radioelements (Belgium); and the Nuclear Energy Corporation of South Africa (NECSA). All four have resisted conversion to LEU, citing concerns about cost and disruption of production.[11] According to a 2004 U.S. Government Accountability Office report, these four producers have used approximately 85 kg of HEU each year.[12] That was enough material to make a few improvised nuclear devices, considering that the IAEA regards 25 kg of HEU as a significant quantity, and independent experts believe that terrorists could fabricate a simple gun-type nuclear weapon with between 40 and 55 kg of weapons-grade HEU.[13]

These major isotope producers have argued that their conversion to LEU was hindered by technical and logistical challenges. The U.S. Department of Energy (DOE), by contrast, has argued that the remaining obstacles to conversion are chiefly financial. [14] Some in the U.S. Congress have also worked on legislation to support, or possibly to mandate, the creation of such production.

Recently, U.S-led efforts to convert isotope production away from HEU use have begun to bear fruit. After completing the conversion of its research reactor to LEU fuel, South Africa initiated the conversion of its Mo-99 production to LEU. With DOE assistance, NECSA achieved the world's first large-scale production of Mo-99 with LEU targets in the summer of 2010. That year, DOE also concluded cooperative agreements with several potential domestic suppliers using alternative Mo-99 production technologies. This funding is expected to enable a gradual decrease in the reliance of the United States, the biggest market for Mo-99, on foreign HEU-based producers.[15]

Some small producers of medical isotopes have commenced production using LEU targets, rather than HEU targets. LEU targets have been irradiated, disassembled, and processed in Australia, Argentina, and Indonesia. Argentina has been exporting isotopes produced using this technology for several years. Australia has been expanding LEU-based medical isotope production after its new OPAL reactor came on line in 2007. Another LEU-based commercial scale facility has been constructed in Egypt. Several other states have set up or explored processes utilizing LEU targets in the production of Mo-99 for both domestic and export purposes.

The IAEA has been a major supporter of these activities. In 2010, the Agency launched an International Working Group to provide assistance in the conversion from HEU to LEU by Mo-99 producers. Additionally, research reactor coalitions have been created to pool regional efforts to produce non-HEU Mo-99. [16]

HEU USE FOR SPACE PROPULSION

HEU has also been used by the Soviet Union and the United States for space propulsion. Fission reactors (with HEU cores) have been used to power satellites in earth orbit. Such reactors were used extensively during the Cold War by the USSR to power their Radar Ocean Reconnaissance Satellites (RORSATs). Notably, these reactors used 90% enriched HEU fuel. A second-generation TOPAZ reactor was also built (using 96% enriched fuel) and deployed by the Soviet Union, although none are currently in operation. Almost all of the HEU material used in these reactors is still in orbit, although the reactors have been shut down. The United States also launched one satellite powered by a fission reactor. Interest in HEU-fuelled reactors for satellites appears to have waned.

In the future, it remains an open question as to whether the U.S. National Aeronautics and Space Administration (NASA) and/or other national space programs will decide to use HEU reactors for deep-space propulsion. NASA has worked on the development of Project Prometheus—a short-lived joint fission propulsion reactor development effort with the U.S. Department of Energy. However, the extent of HEU use in this research and development program remains unclear. Such a program is viewed by many as necessary to power a manned mission to explore Mars, since it could cut months off of the time required for the voyage.

In November 2005, U.S. Secretary of Energy Bodman stated that the Department of Energy would allocate approximately twenty tons of weapons-grade HEU towards the development of space reactors. Despite funding problems, the U.S. nuclear space propulsion program retains strong support.

In turn, Russia has noted that it intends to restart its space reactor program.[18] A number of experts believe that HEU-powered systems have the potential to be a viable technology that could be operated safely and without major proliferation risks (especially since the fuel could be jettisoned in space). Some countries may be reluctant to agree to a ban on civilian HEU if they feel that it may be useful for future space exploration. [19]

HEU USE IN ICEBREAKER PROPULSION REACTORS

Russia is the only country that employs nuclear propulsion for civilian vessels. It launched its first nuclear-powered icebreaker, the Lenin, in 1957. The OK-150 reactors that initially powered Lenin used low-enriched fuel (5%).[20] In order to increase the length of time the ships could operate between refueling, later icebreaker reactors used higher enrichment levels: the OK-900 reactor used 36-45% HEU, the OK-900A—which powers today's five Arktika-class icebreakers—uses 45-75% enriched fuel, [21] while the KLT-40 reactors, which propel the icebreakers Taymyr and Vaygach, as well as the Sevmorput icebreaking freighter, use 90% enriched fuel.[22] The amounts of uranium in the reactor cores are quite significant, with some ships carrying up to 200 kg of U-235.[23] Russia recently launched a new Arktika-class nuclear-powered icebreaker, the 50 Let Pobedy, at the Baltic Shipyard in St. Petersburg.

Russia recently launched a new Arktika-class nuclear-powered icebreaker, the 50 Let Pobedy, at the Baltic Shipyard in St. Petersburg. However, the original service lives of the current icebreakers are expiring, despite refits that extend their service for another 7-8 years. By 2015 Russia will require new icebreakers if it is to maintain transport across the Northern Sea Route and down the Yenisey River.

Russia hopes to build more icebreakers. Russian research institutes have proposed studying the use of LEU fuels in icebreaker reactors. In 2012, RosAtomFlot announced a tender for the world's largest icebreaker. The LK-60 vessel, ambitiously scheduled for delivery by the year 2018, will be 173 metres long and 34 metres wide, substantially larger than 50 Let Pobedy. The new vessel will likely utilize LEU in its two RITM-200 pressurized water reactors, developed by OKBM Afrikantov.[24]

HEU USE IN FAST REACTORS AND POSSIBLE FUTURE NUCLEAR POWER REACTORS

Fast breeder reactors are designed to produce more fissile material than they consume. The surplus fissile material is produced by surrounding the core of the reactor with a blanket of fertile U-238, which is transmuted to Pu-239. However, fast reactors do not have to operate as breeders. The same underlying fast reactor technology can be used to burn (or consume) plutonium and other actinides, such as americium and neptunium. Such reactors are known as fast burner reactors.

Some fast reactors use HEU in their seed fuel, which is loaded into the reactor core, although not all fast reactors are designed to use HEU. A number of countries, including China, France, Germany, India, Japan, and Russia have constructed or are currently developing fast reactors.[25] Most, if not all of such future reactors, will rely on plutonium- or U233-based fuels. India, for example, plans to employ U233 with a thorium blanket, while fast reactors in the European Union now use mixed oxide (MOX) plutonium fuel. If even a small fraction of these reactors were to be fueled with HEU, it could have significant policy implications. (It should be noted that the expanded use of MOX fuel, made from plutonium recovered during spent fuel reprocessing, is not without its own set of proliferation risks. Similarly, the implementation of thorium-based alternatives would commercialize U-233, also a fissile material of proliferation concern. Both plutonium and U-233, in sufficient quantity and quality, unlike LEU, are weapons-useable.)

Testing new core designs for future fast reactors using MOX fuel requires experiments in critical assemblies; this testing may entail the use of 30-35% enriched uranium along with plutonium to mock up some core designs (alternatively, the cores can be mocked up with plutonium alone). However, these tests can be undertaken in a single or a handful of existing critical assemblies, and will not require enrichment higher than 35% (current critical assemblies use up to 90% HEU, interspersed with natural or depleted uranium to mock up lower enrichment levels).[26]

One example of a fast reactor that currently uses HEU fuel is Russia's BN-600 reactor at Beloyarskaya Nuclear Power Plant (NPP). The 600 MW reactor requires three types of fuel for an inner core, an intermediate core, and an outer core. The enrichment level for these fuels varies from just below 20% to 26% U-235. The BN-600 reactor can also use a hybrid core with 75% uranium and 25% MOX fuel to dispose of some of Russia's plutonium.[27] According to the June 2005 IAEA report, the BN-600 annually consumes 6 tons of uranium fuel with U-235 assays, including 4 tons of HEU.[28] If the reactor switches completely to MOX fuel, the consumption of HEU would decline.

The critical question for the future is whether the next generation of nuclear power reactors will require HEU. In the United States, where no new nuclear power reactors have been built for over twenty years, the Department of Energy has launched the Gen IV Nuclear Energy Systems International Forum, an initiative to explore new technological approaches to nuclear power generation.[29] The IAEA has also undertaken the Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO), which is likewise exploring new nuclear power technologies.[30] However, none of the reactors under consideration by these initiatives use HEU as fuel.

FAST REACTORS, PAST AND FUTURE

Several countries are considering the construction of fast reactors in the future. In February 2006 the United States, France and Japan agreed to joint research and development of sodium-cooled fast reactors in support of the Global Nuclear Energy Partnership (subsequently Gen IV, noted above). The IAEA's International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) has also focused on fast reactors. Although past fast reactors have used HEU fuel, future plans focus on the use of plutonium-based fuels.

The first fast reactor ever constructed was the EBR-I (Experimental Breeder Reactor-1) at the Idaho National Engineering and Environmental Laboratory (INEEL) in Idaho Falls, Idaho, in the United States. It operated from 1951 to 1964, when it was replaced by the EBR-II, which was initially used to demonstrate a complete breeder-reactor power plant, and later used to test fuels and materials for larger liquid metal reactors. The world's first commercial fast reactor was also constructed in the United States, at the Enrico Fermi NPP near Detroit, Michigan. This 94MW reactor operated from 1963 to 1972. One other fast reactor has been built in the United States, the Fast Flux Test Facility at the Hanford Site in the state of Washington. The Fast Flux Test Facility is not a breeder, but it is a sodium-cooled fast reactor. It was placed on standby status in 1992, and the decision was later made to shut it down.

The United Kingdom, France, Japan, Russia, Kazakhstan, India, Germany, and Italy have also operated fast reactors, Germany built one that was never operated, and Italy initiated construction of a fast reactor that was never completed. The UK fast reactors were both located at Dounreay, Scotland. The first fast reactor, DFR, was an NaK-cooled reactor that operated from 1959 to 1977, while the second Prototype Fast Reactor (PFR) was a larger, sodium-cooled reactor that operated from 1974 to 1994. Although Dounreay was able to reprocess plutonium economically, by the late 1980s the UK government decided that as uranium was no longer in short supply, fast reactors would not be needed for commercial electricity generation. Thus, funding for the research program at Dounreay was ended and the PFR shut down in 1994.

France constructed the largest fast reactor completed to date, the 1,200 MW Superphénix at Creys-Malville, near the Swiss border. The Superphénix became operational in 1984, but has been closed since 1997, after a series of public protests against the reactor. The Superphénix was preceded by two other French reactors, the Rapsodie (1967-83) and the Phénix, a small-scale (233 MW) prototype fast reactor, located at Marcoule. Before being shut down in 2009, the Phénix operated on MOX fuel and was mainly used to study the transmutation of nuclear waste. France, Germany, and the United Kingdom will continue to use the Masurca critical assembly, at Cadarache, to test new fast reactor core configurations--these tests are important to validate reactor performance and safety characteristics. At present, weapons-grade uranium is used to mock up a portion of the plutonium in the core. However, only 35% enriched material is actually necessary to mock up MOX fuel.[25]

The Japanese MOX-fueled fast reactor, Monju, achieved criticality in April 1994 but has been shuttered since a sodium leak and coolant fire in December 2005 and another accident in August 2010.

The Soviet Union built a  series of fast reactors , beginning with the BR-1 critical assembly in Obninsk in 1955 (fueled with plutonium metal), which was upgraded to 100kW and renamed BR-2 in 1956. The world's first reactor fueled with plutonium oxide fuel, the BR-5, was also built in Obninsk, attaining criticality in 1958. It was known as the BR-10 after a 1964 modification, and operated until December 2002 using 90% enriched uranium fuel. Another Russian institute, the Research Institute of Atomic Reactors (SRIAR) in Dimitrovgrad, is home of the BOR-60 fast reactor, which attained criticality in 1968. The BOR-60, built primarily to provide a materials test bed, uses fuel with uranium enriched to 45-75% U235, though it is also capable of operating on a hybrid core using MOX fuel.

The first full-scale fast reactor built by the Soviets was the BN-350 in western Kazakhstan. Fueled by 20-25% HEU, it supplied both electricity and desalinated water to the city of Aktau from 1973 to 1999. The Soviets later built yet another fast reactor, the BN-600, at the Beloyarsk NPP, which has been in operation since 1980. It uses 17-26% enriched fuel. Finally, developmental and design work for the BN-800 fast reactor was completed, and construction started at Beloyarsk in 1986. However, construction was suspended throughout most of the 1990s.

Russia has also considered two additional fast reactor projects: construction of a BN-1600 and construction of a lead-cooled fast reactor called the BREST-300. Rosatom, Russia's Federal Atomic Energy Agency, has stated that it plans to rely on fast reactors for power generation in the future. The lower House of the Russian parliament, the State Duma, is also supportive of this idea, and has recommended that the Russian government draft a national program for the development of fast neutron reactors. Rosenergoatom, Rosatom's power generating enterprise, projects the construction of up to 20 new liquid-metal-cooled fast reactors by 2020.[30] These plans are widely viewed as overly ambitious, however, given the slow pace of the construction of the BN-800 reactor and insufficient funding.

India's program includes both fast and thermal breeder reactors. Its first fast reactor, the Fast Breeder Test Reactor, attained criticality in 1985. India is building a second fast reactor at Kalpakkam. The Indian fast reactor program has focused on the use of plutonium fuel, and not HEU.

Germany too has constructed fast reactors, but both were closed in 1991. The Kompakte natriumgekühlte Reaktoranlage (KNK II) prototype fast reactor in Karlsruhe achieved criticality in 1977. Construction of the larger SNR-300 reactor at Kalkar was completed in 1985, but for political reasons the reactor was never operated, and has since been decommissioned. Italy, also for political reasons, halted construction of its Prova Elementi Combustibile (PEC) test reactor in 1987. Its Tapiro fast reactor, which first achieved criticality in 1971, is still in operation and uses HEU fuel.

In addition to the general research on fast reactors taking place within the framework of the Gen IV and INPRO programs, several countries have more concrete plans for fast reactor construction. China has built a Zero-Power Fast Critical Reactor in Chengdu, in cooperation with Russia, and has begun to operate a prototype fast reactor, the CEFR, in Beijing (Russia has already provided HEU fuel for the CEFR). The follow-up to the CEFR, however, the China Prototype Fast Reactor (CPFR), slated for development in the 2020 timeframe, may use MOX fuel.[31] India too plans to construct another fast reactor, while South Korea has developed a design for a modular fast reactor for export, the Korea Advanced Liquid Metal Reactor (KALIMER). Both of these are to use plutonium-based fuel.

Sources:
[1] Frank von Hippel "A Comprehensive Approach to Elimination of Highly-Enriched-Uranium from All Nuclear-Reactor Fuel Cycles," Science and Global Security, 12:137-164, 2004, p. 138.
[2] S.C. Mo, et al., "Modification of the RINSC LEU Core to Increase Fluxes for BNCT Study," Proc. 2000 International Meeting on Reduced Enrichment for Research and Test Reactors, Las Vegas, Nevada, October 1-6, 2000. www.rertr.anl.gov, RERTR Meeting Archive, 2000.
[3] Armando Travelli, Status and Progress of the RERTR Program in the Year 2002," presented to the 24th International Meeting on Reduced Enrichment for Research and Test Reactors (RERTR 2002), San Carlos do Bariloche, Argentina, November 3-8, 2002, cited in Nuclear Threat Initiative, "Securing the Bomb 2005: Securing Nuclear Warheads and Materials, Converting Research Reactors," www.nti.org. Also see "Highly enriched uranium in research reactors," prepared by the organizers of the June 2006 Oslo Symposium on Minimization of HEU in the Civilian Nuclear Sector, www.nrpa.no/symposium.
[4] Alexander Glaser and Frank von Hippel, "Global Cleanout: Reducing the Threat of HEU-Fuelled Nuclear Terrorism," Arms Control Today, January/February 2006, www.armscontrol.org.
[5] Alexander Glaser and Frank von Hippel, "Global Cleanout: Reducing the Threat of HEU-Fuelled Nuclear Terrorism," Arms Control Today, January/February 2006, www.armscontrol.org.
[6] Yet another type of reactor is the pulsating reactor, which operates with frequently repeating pulses, and takes an intermediate position between pulse reactors and constant power reactors. The world's only pulsating reactor is at the Joint Institute for Nuclear Research in Dubna, Russia.
[7] Robinson and Ferguson, "An Analysis of the Technical and Political Dimensions of Highly Enriched Uranium Use," pp. 30-35.
[8] Alexander Glaser and Frank von Hippel, "Global Cleanout: Reducing the Threat of HEU-Fuelled Nuclear Terrorism," Arms Control Today, January/February 2006, www.armscontrol.org.
[9] Research Reactor Database, International Atomic Energy Agency, http://nucleus.iaea.org, 31 October 2012.
[10] Armando Travelli, "Fuel Issues: Replacement of HEU," IAEA Scientific Forum, Sept. 22, 2004, p. 2.
[11] A.J. Kuperman, "The Global Threat Reduction Initiative and Conversion of Isotope Production to LEU Targets," paper presented at the 2004 RERTR Conference, Vienna, Austria, November 7-11, 2004, p. 3, www.rertr.anl.gov.
[12] U.S. Government Accountability Office, DOE Needs to Take Action to Further Reduce the Use of Weapons-Usable Uranium in Civilian Research Reactors, GAO-04-807, July 2004, p. 2.
[13] Charles D. Ferguson and William C. Potter, et. al., Four Faces of Nuclear Terrorism, (New York: Routledge, 2005), pp. 131-135.
[14] Daniel Horner, "Main Barriers to LEU Conversion for Isotopes not Technical, U.S. Says," Nuclear Fuel, January 2, 2006, pp. 3-5. At the June 2006 Symposium on the Minimization of HEU in the Civilian Nuclear Sector, www.nrpa.no, held in Oslo, Norway, Argonne National Laboratory's George F. Vandegrift presented a report entitled "Facts and Myths Concerning 99Mo Production with HEU and LEU Targets." The presentation, which indicates that there are no technical, only commercial, obstacles to converting to the use of LEU targets for isotope production, made available to NTI by permission. For an additional briefing on isotope production, "Highly enriched uranium (HEU) and production of medical isotopes," prepared by the organizers of the June 2006, Oslo Symposium on Minimization of HEU in the Civilian Nuclear Sector, www.nrpa.no.
[15] Miles Pomper, "The 2012 Nuclear Security Summit and HEU Minimization," paper prepared for the U.S.-Korea Institute at SAIS, January 2012.
[16] E. Bradley, K. Alldred, P. Adelfang, N. Ramamoorthy, and D. Ridikas, "IAEA Activities to Support the Transition of Molydbenum-99 Production Away from the Use of Highly Enriched Uranium," paper presented at the 2010 RERTR international meeting, 10-14 October 2010.
[17] Text of the resolution at www.nti.org.
[18] "Nuclear 'a stepping stone' to space exploration," Word Nuclear News, 27 July 2012, www.world-nuclear-news.org.
[19] R. Blake Messer, "HEU in Space Nuclear Reactors: Policy History and Prospects," University of Texas, April 2011, www.heuphaseout.org.
[20] Nikolay Khlopkin, Boris Pologikh, Yuriy Sivintsev, and Vladimir Shmelev, "Preliminary Study of Sea Radioactive Contamination from Dumped Nuclear Reactors," Kurchatov Institute Report No. 31/1-1949-93, 1993, as cited in Ole Reistad, Morten Bremer Mærli, and Nils Bøhmer, "Russian Naval Nuclear Fuel and Reactors: Dangerous Unknowns," Nonproliferation Review, Vol. 12, No. 1 (March 2005), pp. 174-176.
[21] Data on OK-900 and OK-900A from Nikolay Melnikov, Vladimir Konukhin, Vadim Naumov, Pavel Amosov, Sergey Gusak, Andrey Naumov, Yuriy Katkov, Yuriy Smirnov, Aleksandr Orlov, and Yuriy Rybin, "Dolgovremmennoye bezopasnoye khraneniye otrabotavshego yadernogo topliva sudovykh yadernykh ustanovok v Severo-Zapadnom regione Rossii," Gornyy institut Kolskogo nauchnogo tsentra Rossiyskoy akademii nauk Rossiya, p. 4.
[22] Ole Reistad, Morten Bremer Mærli, and Nils Bøhmer, "Russian Naval Nuclear Fuel and Reactors: Dangerous Unknowns," Nonproliferation Review, Vol. 12, No. 1 (March 2005), pp. 181-183.
[23] Nikolay Melnikov, Vladimir Konukhin, Vadim Naumov, Pavel Amosov, Sergey Gusak, Andrey Naumov, Yuriy Katkov, Yuriy Smirnov, Aleksandr Orlov, and Yuriy Rybin, "Dolgovremmennoye bezopasnoye khraneniye otrabotavshego yadernogo topliva sudovykh yadernykh ustanovok v Severo-Zapadnom regione Rossii," Gornyy institut Kolskogo nauchnogo tsentra Rossiyskoy akademii nauk Rossiya, p. 4.
[24] "Russia plans largest icebreaker," World Nuclear News, 4 July 2012, www.world-nuclear-news.org.
[25] IAEA Fast Reactor Database, www-frdb.iaea.org.
[26] Massimo Salvatores, Amine Khalil, Gilles Bignan, Robert Hill, Robert Jacqmin, and Jean Tommasi, "Advanced Fast Reactor Development Requirements: is there any need for HEU?" Cadarache/Argonne, April 2006.
[27] The U.S.-Russian plutonium disposition program intends to burn 34 t of plutonium from dismantled warheads in commercial reactors. Russia tested the possibility of using MOX fuel fabricated from this plutonium in BN-600. The tests with the MOX fuel were successful. However, the use of MOX fuel to burn plutonium from nuclear warheads depends on the prospects of the Pu disposition program and on the agreement between the United States in Russia to indeed use BN-600 for this program. So far, the United Stateshas indicated a preference for using light-water reactors to burn MOX fuel under this program.
[28] Management of high enriched uranium for peaceful purposes: Status and trends, IAEA-TECDOC-1452, June 2005, p. 11.
[29] Gen IV Nuclear Energy Systems, U.S. Department of Energy, Office of Nuclear Energy, Science, and Technology, http://gen-iv.ne.doe.gov.
[30] International Project on Innovative Nuclear Reactors and Fuel Cycles, International Atomic Energy Agency, Nuclear Power Technology Development Section, www.iaea.org.
[31] Alexei Breus, "Russian Duma Calls for National Strategy Favoring Fast Reactors," Nucleonics Week, April 21, 2005, p. 6.