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By Ali Ahmad, Frank von Hippel, Alexander Glaser, and Zia Mian

A Win-Win Solution For Iran’s Arak Reactor

n November 2013, Iran and the P5+1 group This article proposes technical steps that would provide assurance that Iran could of countries (China, France, Germany, not quickly make sufficient for a with the Arak reactor Russia, the United Kingdom, and the while at least maintaining the reactor’s I performance in peaceful applications. United States) agreed on a six-month Joint Plan The solution proposed here involves changing the fueling and operating power of Action to enable negotiations on a final of the Arak reactor to make it less of a proliferation concern. The case of Algeria’s settlement to contain the proliferation risks from Es-Salam provides a useful precedent. Iran’s nuclear program. The U.S. discovery in 1991 that China was building a reactor in Algeria that, like This interim agreement freezes Iran’s not to separate plutonium from spent the Arak reactor, would be fueled with enrichment capacity, thereby preventing a nuclear or construct a facility capable natural and use heavy as further shortening of the time Iran would of doing so. These are important interim a moderator caused a diplomatic require to produce weapons quantities commitments. crisis. Based on satellite imagery, the of highly (HEU) if it According to Ali Akbar Salehi, the United States estimated that the reactor’s wished.1 This enrichment capacity has head of the Atomic Organization power could be as high as 50 megawatts expanded greatly over the years since it of Iran, the Arak reactor is intended for thermal (MWt), in which case, if it were first came to international attention in radioisotope production and testing of fueled with , it would 2002. and materials. In response be able to produce as much as “10 to 13 Iran and the P5+1 also have agreed on to the P5+1 proposal that Iran scrap the kilograms per year” of plutonium—more the need to constrain Iran’s option to Arak reactor project, Salehi stated that “we than enough for a simple nuclear weapon. produce plutonium for weapons using the see no point stopping the work on this China informed the United States, reactor that is under construction near reactor.” He has acknowledged, however, however, that the reactor’s design power the city of Arak and that will be under the international community’s concerns would be 15 rather than 50 MWt and that International Atomic Energy Agency about the Arak reactor and offered the the fuel provided would be enriched to (IAEA) safeguards. possibility of design changes “in order to 3 percent in the chain-reacting Under the Joint Plan of Action, Iran has produce less plutonium in this reactor and uranium-235 rather than natural uranium, agreed to freeze the Arak reactor project in this way allay the worries and mitigate which contains only 0.7 percent U-235. for six months.2 It also has committed the concerns.”3 The United States calculated that, with that

ARMS CONTROL TODAY April 2014 ARMS CONTROL TODAY Ali Ahmad, Frank von Hippel, Alexander Glaser, and Zia Mian are members of the Program on Science and Global Security at Princeton University. 8 Figure 1: Alternative Core Designs for the Arak Reactor In the figure below, Core A represents the natural uranium-fueled 40-megawatt thermal M( Wt) core of the Arak reactor. The diameter of the core is 3.2 meters, and its height is 3.4 meters. The light hexagons mark the channels that hold the fuel. The dark hexagons around the edge hold as a . The dark hexagons within the core mark channels that are available for irradiating targets to produce radioisotopes for medicine or for other purposes. Core B is the redesign that would operate at 10 MWt with a core height of 2.4 meters, fueled with enriched uranium inside the same tank. An intermediate 20-MWt core (not shown here) also has been analyzed. Because the lower-power cores fueled with enriched uranium are more compact, the neutron in their irradia- tion channels would be comparable to that of the natural uranium design operating at 40 MWt.

Fuel

Target

Reflector

Core A Core B

Source: Ali Ahmad, Frank von Hippel, Alexander Glaser, and Zia Mian. fuel and power, the reactor would produce at full power about 300 days per year, no evidence or even claim that it is doing in its spent fuel “slightly less than 1 natural uranium fuel could be kept in so. Yet, there is the theoretical possibility kilogram of plutonium per year.”4 With the its core for about 3.5 years. The analysis that a small “quick and dirty” reprocessing additional commitment that the reactor in this article assumes that during this plant could be constructed clandestinely. would be placed under IAEA safeguards, period, the reactor would be refueled three The IAEA assumes for the purpose of the crisis was resolved. A similar solution is times with one-third of the fuel in the designing its safeguards that it would take available for the Arak reactor. reactor core replaced at each refueling. The one to three months to separate enough discharged fuel would be placed in an on- plutonium for a weapon.7 The Arak Research Reactor site, water-filled cooling pool. Furthermore, the Arak reactor is not the The 40-MWt Arak research reactor is a Under this scenario, the pool would only potential source of plutonium in Iran. proliferation concern in part because other contain 27 kilograms of unseparated The Bushehr 3,000-MWt power reactor has countries have used this type of reactor to plutonium after the third discharge. The much more plutonium in its core and in its produce plutonium for nuclear weapons fuel still in the reactor core could contain than Arak is likely to have. (see box, page 10). Reactors that use natural up to another 20 kilograms. Therefore, If an annual fuel reload were discharged uranium fuel are especially well suited for the plutonium inventory on the reactor early from the Bushehr reactor after the plutonium production because virtually site, including the amount in the reactor, fuel achieved about 15 percent of its design all of the they produce that are would be up to 50 kilograms.5 Most of this burn-up (several months), it would contain excess to the requirements for maintaining plutonium would not be weapons grade, about 50 kilograms of weapons-grade ARMS CONTROL TODAY April 2014 the fission are absorbed in but it would be weapons usable.6 Using the plutonium.8 The relatively large amount of the uranium-238, which constitutes 99.3 IAEA estimate of 8 kilograms of plutonium plutonium in irradiated fuel at the Bushehr percent of the fuel. The addition of the for a first-generation nuclear weapon, 50 reactor is one reason why the IAEA is neutron turns U-238 into uranium-239, kilograms would be enough for about six inspecting it quarterly. which quickly decays into plutonium-239. weapons. Very few neutrons are left over for use in Before it could be used for a weapon, The Light-Water Alternative research and radioisotope production. To however, the plutonium in the spent In 2005, because of their proliferation gain more neutrons, heavy-water reactors fuel would have to be separated out in a concerns about the Arak reactor, France, are designed to operate at high power, remotely operated chemical reprocessing Germany, and the UK—the group that which requires more nuclear fuel and plant behind heavy shielding. Iran has was the predecessor to the P5+1—offered larger reactor cores. repeatedly stated that it has no intention of to help Iran obtain a light-water research Assuming that the Arak reactor operates building a reprocessing plant, and there is reactor instead.9 This is still the proposal of 9 the P5+1 in its talks with Iran. Such a reactor would most likely be a higher-power, more modern version of Research Reactors and the Tehran Research Reactor, which the Nuclear Weapons Programs United States provided Iran in 1960 under the Atoms for Peace program. The Tehran eactors that are fueled with natural uranium and use heavy water as facility is a 5-MWt, pool-type reactor Ra neutron moderator have been used to produce plutonium for use in whose fuel today is 19.75 percent enriched weapons since the . Almost all of the neutrons that are in U-235. This is just below the 20 percent produced beyond those required to sustain the uranium-235 fission chain threshold above which uranium is reaction in the fuel are absorbed by uranium-238 to produce plutonium. U-238 considered to be weapons usable. The core is 140 times more abundant in natural uranium fuel than is U-235. The first of the Tehran reactor is a small rectangular heavy-water reactor, Canada’s 40-megawatt thermal (MWt) NRX, on which cuboid that sits at the bottom of a deep construction began in 1944, was originally designed to provide plutonium pool of “light” (ordinary) water. The water for the wartime U.S. nuclear weapons program.1 India, Israel, and Pakistan is pumped through the core to cool it and currently use reactors of this basic type to produce their weapons plutonium, provides shielding for workers and other countries have built such reactors for that purpose. using the reactor. Pool-type light-water research reactors • Israel’s Dimona reactor, which was supplied by France, was originally rated are attractive because they are simple and at 26 MWt when it came online in 1963, but is believed to have been uprated to their compact cores are intense sources of at least 70 MWt.2 neutrons. Of the nine isotope production reactors worldwide in the power range of • India’s 40-MWt CIRUS reactor, based on the NRX design, produced enough 10 to 30 MWt whose construction began plutonium on average for about one bomb per year during its operating in 1980 or later, eight are light-water pool- life from 1963 to 2010. In 1985, India completed a second, larger 100-MWt type reactors.10 The ninth is Algeria’s Es- heavy-water “research” reactor, Dhruva, to increase the rate of growth of its Salam heavy-water reactor. stockpile.3 Light-water research reactors fueled with 19.75 percent-enriched uranium produce • Pakistan began operating a 40- to 50-MWt reactor at Khushab in 1998 to much less plutonium than reactors fueled produce plutonium for its nuclear weapons program. Since then, it has built 4 with natural uranium because there are two more reactors of this type, and work is under way on a fourth. only about four U-238 nuclei in their fuel ENDNOTES for every U-235 nucleus, a proportion much lower than the 140-to-1 ratio in 1. D.G. Hurst and A.G. Ward, “Canadian December 2010, ch. 8, http://fissilematerials. natural uranium fuel. As a result, a 20- Research Reactors,” Atomic Energy of org/library/gfmr10.pdf. MWt light-water research reactor operated Canada, Ltd., 1956. 3. Ibid., ch. 9. 300 days a year would produce only 0.7 2. International Panel on Fissile Materials, kilograms of plutonium a year and would 4. Ibid., ch. 10. “Global Report 2010,” have on average about 1 kilogram of plutonium in its core.11 The IAEA must monitor the use of such reactors to ensure Iran recognizes the efficiency of pool- install the core of a pool-type reactor at the that natural uranium targets are not placed type light-water reactors for research and bottom. in or around the core to produce more radioisotope production. In February, Iran Iran takes pride in the Arak reactor, plutonium. informed the IAEA that a “10 MW light however, and is unwilling to scrap it in At the same time, because such a small water pool type research reactor with 20 exchange for a light-water research reactor. fraction of their neutrons is wasted on percent enriched uranium oxide fuel, Salehi emphasized its importance as a the production of plutonium, relatively is planned to be constructed in order to scientific and technological achievement.15 low-power light-water research reactors fulfill the national demand on educational As he suggested, however, there exist can produce large quantities of medical nuclear research, material testing, medical plausible options for modest changes in radioisotopes. The operators of Australia’s radio production and other beam the operation of the Arak reactor that multipurpose 20-MWt OPAL reactor, for line application.”14 It appears, however, would dramatically reduce its plutonium example, plan to produce and mostly that Iran intends to build this new reactor production without reducing its export 2,700 six-day curies per week of in addition to the Arak reactor rather than performance as a research reactor. These molybdenum-99, the primary radioisotope as an alternative. changes could be a basis for a mutually used in medicine.12 Iran currently The Arak reactor perhaps could be acceptable solution. imports from Russia 100 six-day curies converted into a light-water pool-type of this product per week to supplement reactor. If the pressure vessel were Reducing Plutonium Production the production by the Tehran Research removed, it might be possible to flood the The amount of plutonium produced ARMS CONTROL TODAY April 2014 ARMS CONTROL TODAY Reactor.13 radiation shield chamber with water and in the Arak reactor could be reduced 10 drastically with the implementation of two each power level enriched to 5 or 19.75 the enrichment of a research reactor’s complementary measures. percent U-235. fuel without changing the geometry of Converting the Arak reactor to 5 the fuel or core. Between 2001 and 2010, • Convert the reactor from percent-enriched fuel might be preferable 20 research reactors were converted from using natural uranium fuel to to converting to 19.75 percent-enriched using weapons-grade uranium fuel to low-enriched uranium fuel. For fuel. If Iran produces its own fuel for the 19.75 percent-enriched fuel.20 That was a a given reactor power, the total Arak reactor, it would be better that it not reduction of fuel enrichment rather than quantity of U-235 in the fuel have a reason, in the near term at least, to the increase for Arak discussed here, but

[T]here exist plausible options for modest changes in the operation of the Arak reactor that would dramatically reduce its plutonium production without reducing its performance as a research reactor.

would not change because using produce more uranium that is enriched the approach is the same. The analysis less-dense fuel would compensate to almost 20 percent. Uranium enriched for this article has examined the effect of for the increased enrichment. to that level requires much less additional reducing the concentration of uranium in The quantity of U-238, however, enrichment to reach weapons grade (an the fuel while the enrichment is increased would be greatly reduced, and the enrichment level of 90 percent or more). so that the amount of U-235 in the fuel quantity of plutonium produced Iran has produced enough uranium stays constant. This would require Iran to would be reduced almost in enriched to almost 20 percent to fuel make a different kind of fuel for Arak than proportion.16 the Tehran Research Reactor for several the uranium dioxide fuel that is currently years at least and has suspended further planned. • With low-enriched fuel, the production as a confidence-building currently used in most research power could be reduced to 20 or measure under the Joint Plan of Action. reactors are made by dispersing uranium- even 10 MWt, further reducing The need to produce 5 percent-enriched containing material in aluminum to make plutonium production. With a uranium for Arak could not be used by the “meat” of the fuel and then sealing proportionately smaller core, the Iran to legitimize a large enrichment that meat inside aluminum cladding to reactor still would have at least capacity. About 1,300 of Iran’s first- isolate the uranium and its fission products as large a capacity to produce generation centrifuges, the IR-1, could from the cooling water. Iran already is neutrons for medical isotopes produce enough material to fuel the Arak producing one such fuel for the Tehran and for scientific research as the reactor operating at 20 MWt.19 It would Research Reactor in which the uranium is 21 current design, a 40-MWt reactor take twice as much enrichment capacity in the form of the uranium oxide U3O8. fueled by natural uranium. to provide enough 19.75 percent-enriched This fuel can be produced with uranium uranium to fuel a light-water research densities as high as 3.2 grams of uranium These options were examined for reactor with the same power. per cubic centimeter.22 Five percent- variations of Arak’s current core design With regard to plutonium production in enriched fuel for the Arak reactor would (fig. 1 [Core A], page 9). Because Iran the fuel of the various cores, the analysis require a uranium density of about 1.3 has not publicly released the full design conducted for this article found that when grams per cubic centimeter, which would details of the Arak reactor, the 40-MWt fueled with 5 percent-enriched uranium, be relatively straightforward to fabricate. design created by a group of Norwegian the Arak reactor, operating at 20 MWt, Converting to enriched uranium fuel ARMS CONTROL TODAY April 2014 researchers, based on descriptions in would produce no more plutonium in its would make more neutrons available Iranian publications, is used for reference fuel than a light-water research reactor of for radioisotope production and other here.17 The core contains 8.7 metric tons of the same power fueled with 19.75 percent- purposes. Arak reportedly is designed with natural uranium in the form of 10 metric enriched uranium (table 1, page 12). If eight channels reserved for purposes such tons of uranium dioxide.18 the Arak reactor were fueled with 19.75 as irradiating radioisotope production The analysis below compares the percent-enriched uranium, the amount of targets and test fuel.23 A much smaller performance of this design with that of plutonium produced in its fuel would be 5 percent-enriched core could produce two possible alternative smaller cores in one-quarter the amount produced in the as many neutrons for such purposes the same reactor vessel with heavy water core of a light-water research reactor with operating at 10 MWt as could the large as a moderator but with the power level the same power. natural uranium core operating at 40 reduced to 20 or 10 MWt and the fuel at It is well understood how to change MWt.24 11 IR-1 centrifuges.26 Table 1: Plutonium Production for Different Fuel Thus, if the Arak reactor is converted to Enrichments and Power Outputs operate on enriched uranium at reduced The table below lists the calculated annual plutonium production in the power, it is likely to be less of a breakout fuel of the current Arak design and in alternative cores assuming full-power threat than Iran’s enrichment program. operation 300 days per year. The highlighted line shows that when fueled The conversion steps described above are with 5 percent-enriched uranium, the Arak reactor would produce about technically feasible and would not reduce the same amount of plutonium in its fuel as a light-water research reactor of the same power fueled with 19.75 percent-enriched uranium. Arak’s usefulness for civilian purposes. They provide a sound basis for resolving Annual plutonium production one of the key points of contention in the Reactor/fuel combination (kilograms per year) talks on Iran’s nuclear program. 40 MWt 20 MWt 10 MWt Heavy-water research reactor, ENDNOTES 7.70 natural uranium fuel 1. See International Atomic Energy Agency Heavy-water research reactor, 0.72 0.34 (IAEA), “Communication Dated 27 November 5 percent-enriched fuel 2013 Received From the EU Representative Heavy-water research reactor, 0.18 0.09 Concerning the Text of the Joint Plan of 19.75 percent-enriched fuel Action,” INFCIRC/855, November 27, 2013 Light-water research reactor, 0.70 0.35 (contains the Joint Plan of Action as an 19.75 percent-enriched fuel attachment) (hereinafter Joint Plan of Action); Source: Ali Ahmad, Frank von Hippel, Alexander Glaser, and Zia Mian. Office of the Press Secretary, The White House, “Summary of Technical Understandings Related In summary, any of the redesigns of potential to quickly produce enough to the Implementation of the Joint Plan of the Arak reactor suggested here would plutonium or HEU for a weapon. A relevant Action on the Islamic Republic of Iran’s Nuclear reduce plutonium production to less than question is how the breakout potential Program,” January 16, 2014, http://www. 1 kilogram per year, comparable to the of an Arak reactor fueled with enriched whitehouse.gov/the-press-office/2014/01/16/ reduction that would be accomplished uranium and operating at reduced power summary-technical-understandings-related- by replacing the Arak reactor with a would compare with the proliferation risk implementation-joint-plan-actio. light-water research reactor. At the same from Iran’s uranium-enrichment program. time, these redesigns would not reduce The small amount of plutonium in the 2. Joint Plan of Action, fn. 3. the usefulness of the reactor for making 5 percent-enriched spent fuel means that, 3. “Arak Heavy Water Reactor Is for radioisotopes and conducting research. to make a weapon quantity of plutonium Peaceful Research: Dr. Salehi (Part 2),” Thus, this approach would meet Iran’s in a hurry, Iran first would have to Press TV, February 5, 2014, www.presstv.ir/ needs and would address the concerns of manufacture about 2,700 natural uranium detail/2014/02/05/349340/false-allegations- the international community as reflected fuel rods for the reactor. It then would wont-stop-arak-reactor/. by the P5+1. replace its enriched fuel with this natural To prevent the accumulation of large uranium fuel and operate the reactor at 40 4. U.S. Department of State, “Talking Points on amounts of plutonium-bearing spent fuel MWt continuously for nine months. These Algerian Nuclear Developments for Delivery to at Arak, the spent fuel could be shipped actions would be quickly detected by IAEA Senators Glenn and Roth (SGA), Senators Pell out after a few years. Russia already has inspectors. The fabrication of the natural and Helms (SFRC), and Congressmen Fascell agreed to remove the spent fuel from uranium fuel would provide additional and Broomfield (HFAC),” July 29, 1991, http:// Iran’s Bushehr reactor after it has cooled warning unless Iran had established a www2.gwu.edu/~nsarchiv/nukevault/ebb228/ sufficiently. Ordinarily, spent fuel from clandestine fuel-fabrication plant. After Algeria-18.pdf. light-water power reactors is not shipped that, it would take months to separate the 5. It would be 47 kilograms with a full core until it has cooled for five years, but it can plutonium even if Iran had clandestinely in the pool and just before discharge of an be shipped sooner with a reduced loading constructed a reprocessing plant. The total additional one-third of a core. of fuel per transport cask. The Bushehr breakout time would be at least a year. reactor will discharge about 27 metric tons For comparison, the Institute for Science 6. The plutonium isotope produced by neutron of spent fuel a year. It would be a minor and International Security estimates it capture in U-238 is plutonium-239. If this matter to add to the shipments of its spent would take Iran’s enrichment program isotope absorbs a second neutron, there is about fuel the approximately 0.1 to 0.2 metric significantly less than six months to a 27 percent chance that it will not fission but tons of 5 percent-enriched spent fuel that produce one weapon’s worth of HEU.25 To rather turn into plutonium-240. In the United would be discharged annually by the Arak increase this breakout time to six months, States, weapons-grade plutonium is defined as reactor operating at 10 to 20 MWt. Iran would have to reduce its enrichment containing less than 7 percent plutonium-240. capacity from the equivalent of the See U.S. Department of Energy, “Plutonium: Breakout Potential approximately 19,000 IR-1 centrifuges The First 50 Years,” DOE/DP-0137, February The overarching goal of the P5+1 it had operating or installed in early 1996, p. 17. The fuel discharged from the Arak ARMS CONTROL TODAY April 2014 ARMS CONTROL TODAY negotiations with Iran is to limit Iran’s February to the equivalent of only 4,000 reactor after 3.5 years would contain 21 percent 12 plutonium-240. With regard to the weapons 12. National Research Council, “Medical generation centrifuges is 0.9 separative work usability of non-weapons-grade plutonium, the Isotope Production Without Highly Enriched units per year, the produced Department of Energy has written, Uranium,” January 14, 2009, p. 44; “Australia has an assay of 0.4 percent, the core contains Greenlights ‘Mega Moly’ Project,” Nuclear 600 kilograms of 5 percent-enriched uranium, At the lowest level of sophistication, Engineering International, January 1, 2013, www. and the fuel life in the reactor is three years. a potential proliferating state or neimagazine.com/features/featurebox-australia- subnational group using designs and 20. Ferenc Dalnoki-Veress, “Primarily Positive greenlights-mega-moly-project/. Six-day curies technology no more sophisticated Perceptions: A Survey of Research Reactor measure the quantity of molybdenum-99 left than those used in first-generation Operators on the Benefits and Pitfalls of a week after it has been produced in a reactor. nuclear weapons could build a Converting From HEU to LEU” (paper presented Assuming 10 percent losses and one day of nuclear weapon from reactor grade at the European Research Reactor Conference, decay during extraction from the neutron plutonium [containing at least 19 Ljubljana, Slovenia, April 1, 2014). “target,” 15 percent of the molybdenum-99 in percent plutonium-240] that would the target would remain after an additional 21. IAEA, “Implementation of the NPT have an assured reliable yield of one six days of decay during shipping and use at a Safeguards Agreement and Relevant Provisions or a few kilotons (and a probable hospital. of Security Council Resolutions in the Islamic yield significantly higher than that). Republic of Iran,” para. 58 and annex 2, tables At the other end of the spectrum, 13. “Russia Ready to Supply Iran With Medical 5 and 6. advanced nuclear weapon states Isotopes Molybdenum and Iodine,” Interfax such as the United States and Russia, Azerbaijan, February 22, 2011, http://interfax. 22. Argonne National Laboratory, “Currently- using modern designs, could produce az/view/458081 (in Russian). Qualified Fuels,” July 29, 2008, http://www. weapons from reactor-grade plutonium rertr.anl.gov/QualFuel.html. 14. IAEA, “Implementation of the NPT having reliable explosive yields, weight Safeguards Agreement and Relevant Provisions 23. Mehdi Hashemi-Tilehnoee, Ali Pazirandeh, and other characteristics generally of Security Council Resolutions in the Islamic and Saman Tashakor, “HAZOP-Study on Heavy comparable to those of weapons made Republic of Iran,” GOV/2014/10, February 20, Water Research Reactor Primary Cooling with weapon-grade plutonium. 2014. System,” Annals of Nuclear Energy, Vol. 37, No. 3 U.S. Department of Energy, “Nonproliferation (March 2010): 428-433. 15. Ali Akbar Salehi, head of the Atomic and Arms Control Assessment of Weapons- Energy Organization of Iran, in response to 24. The cumulative yield of 2.74-day half-life Usable Fissile Material Storage and Excess the question, “Why do you want this thing, molybdenum-99 from thermal fission of U-235 Plutonium Disposition Alternatives,” DOE/NN- why do you want this whole international, is 6.11 percent. T. R. England and B. F. Rider, 0007, January 1997, pp. 38-39. Western dispute over this particular issue [the “Evaluation and Compilation of Fission Product 7. IAEA, “IAEA Safeguards Glossary, 2001 Arak reactor]?” said, “First of all it is a scientific Yields, 1993,” ENDF-349, LA-UR-94-3106, Edition,” International Nuclear Verification Series, achievement, it is a technological achievement.” October 1994. For 20 percent-enriched uranium No. 3 (2002), p. 22, table 1. “Arak Heavy Water Reactor Is for Peaceful metal targets 0.5 millimeters thick irradiated Research.” for seven days, a one meter-high stack of targets 8. These calculations assume 2 grams per containing 116 grams of uranium in the central kilogram of uranium in 27 metric tons of fuel 16. The reduction is not exactly in proportion channel would produce 1,800 six-day curies a with an average burn-up of 5 MWt-days per because, with a lower density of U-238, the week. kilogram. nuclei shield one another from neutrons to a lesser degree. 25. Assuming a large stock of 3.5 percent- 9. IAEA, “Communication Dated 8 August 2005 enriched uranium and 68 kilograms of 19.75 Received From the Resident Representatives of 17. Thomas Mo Willig, Cecilia Futsaether, and percent uranium (equivalent to 100 kilograms France, Germany and the United Kingdom to Halvor Kippe, “Converting the Iranian Heavy of uranium hexafluoride) as feedstock. the Agency,” INFCIRC/651, August 8, 2005. Water Reactor IR-40 to a More Proliferation- Institute for Science and International Security, Resistant Reactor,” Science & Global Security, Vol. 10. The eight pool-type light-water reactors “Defining Iranian Nuclear Programs in a 20, Nos. 2-3 (October 2012): 97-116. For more are OPAL (Australia, 20 MWt, 2002), FRM-II Comprehensive Solution Under the Joint Plan detail, see Thomas Mo Willig, “Feasibility and (Germany, 20 MWt, 1996), ETRR-2 (Egypt, 22 of Action,” January 15, 2014, http://www. Benefits of Converting the Iranian Heavy Water

MWt, 1992), HANARO (South Korea, 30 MWt, isisnucleariran.org/assets/pdf/Elements_of_a_ ARMS CONTROL TODAY April 2014 Reactor IR-40 to a More Proliferation-Resistant 1987), JRR-3M (Japan, 20 MWt, 1985), RSG-GAS Comprehensive_Solution_20Jan2014_1.pdf. Reactor,” Norwegian University of Life Sciences, (Indonesia, 30 MWt, 1983), IRT-1 (Libya, 10 2011. This group also examined the possibility 26. For the numbers of Iran’s installed MWt, 1980), and RP-10 (Peru, 10 MWt, 1980). of converting the Arak reactor to low-enriched centrifuges as of February 2014, see IAEA, IAEA, “Research Reactors,” http://nucleus.iaea. uranium but limited itself to uranium dioxide “Implementation of the NPT Safeguards org/RRDB/RR/ReactorSearch.aspx?rf=1. fuel. Agreement and Relevant Provisions of 11. Alexander Glaser, “On the Proliferation Security Council Resolutions in the Islamic 18. Willig, “Feasibility and Benefits of Potential of Uranium Fuel for Research Reactors Republic of Iran.” To get the number of first- Converting the Iranian Heavy Water Reactor at Various Enrichment Levels,” Science and generation equivalents, it has been assumed IR-40 to a More Proliferation-Resistant Reactor,” Global Security, Vol. 14, No. 1 (2006): 10, table 4 that each second-generation IR-2M centrifuge p. 66. (assuming 40 percent burn-up of the U-235 in is the equivalent of five first-generation IR-1 the fuel). 19. This assumes that the capacity of the first- centrifuges. 13