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Briefings & Information Plutonium and ProliferationMarch
2000 In addition around 100 tonnes of weapons-grade plutonium is due to be released from dismantled nuclear warheads by the US and Russia. Latest figures for UK stocks of separated civil plutonium show that they grew by almost 9 tonnes in 1998 to just over 66 tonnes, of which some 10 tonnes belonged to overseas customers ('UK Annual Civil Plutonium and Uranium Figures', DTI, 21.6.99). A modern nuclear warhead contains about 4 kgs of plutonium. The 24 tonnes of separated plutonium recovered each year is sufficient for 6000 weapons. A stockpile of separated plutonium, including weapons plutonium, of around 500 tonnes in 2010 would be enough for 125,000 weapons if all of this material was diverted or stolen. Obviously this is an unrealistic scenario, but the diversion or theft of as little as 0.1% of this material could lead to the production of 125 illicit weapons - sufficient to severely imperil world security. The IAEA's Illicit Trafficking Database, which covers 61 states, already contains details of over 250 confirmed black-market incidents involving nuclear material (138) or other radioactive sources (124) (IAEA Bulletin, Vol 41, No 4, 1999). Suitability of reactor-grade plutonium for nuclear weaponsFor many years the nuclear industry has hidden behind the smokescreen that the plutonium produced in civil nuclear reactors was unsuitable for use in nuclear weapons. Today, that contention is no longer tenable:- * The IAEA has always classed all types of plutonium, except that containing more than 80% Pu 238, as direct use material. In 1990, in a letter to the Nuclear Control Institute in Washington, Hans Blix, the Director General, confirmed that "The Agency considers high burnup reactor-grade plutonium and in general plutonium of any isotopic composition.......to be capable of use in a nuclear explosive device. There is no debate on the matter in the Agency's Department of Safeguards" (Cited in 'IPPNW Global Health Watch Report No 1'. Cambridge, MA, 1996 p8). * In 1993, J Carson Mark, former Head of the Theoretical Division at LANL, who had been intimately involved in the design of both fission and thermonuclear weapons, outlined four differences between reactor-grade and weapon-grade plutonium that would need to be taken into account when building a nuclear weapon - the need for a larger critical mass (c. 30%); greater heat output; neutron emission from the spontaneous fission of Pu 240; and greater radiation exposure. He concluded that "Reactor-grade plutonium with any level of irradiation is a potentially explosive material......The difficulties of developing an effective design of the most straightforward type are not appreciably greater with reactor-grade plutonium than those that have to be met for weapons-grade plutonium" (J Carson Mark, 'Explosive Properties of Reactor-Grade Plutonium', Science and Global Security, Vol 4, 1993, pp111-128). * In 1994 the US National Academy of Sciences Committee on International Security and Arms Control (CISAC), in a study into excess weapons plutonium disposition, was explicit "Plutonium of virtually any isotopic composition, however, can be used to make nuclear weapons. Using reactor-grade rather than weapons-grade plutonium would present some complications. But even with relatively simple designs such as that used in the Nagasaki weapon -- which are within the capabilities of many nations and possibly some subnational groups -- nuclear explosives could be constructed that would be assured of having yields of at least 1 or 2 kilotons. Using more sophisticated designs, reactor-grade plutonium could be used for weapons having considerably higher minimum yields. Thus the difference in proliferation risk posed by separated weapons-grade plutonium and separated reactor-grade plutonium is small in comparison to the difference between separated plutonium of any grade and unseparated material in spent fuel." (CISAC Report, "Management and Disposition of Excess Weapons Plutonium", National Academy Press, Washington DC, 1994 p4). * In 1995, a Special Panel of the American Nuclear Society, comprising senior representatives from not only the US but also from Russia, France, Germany, Japan and the UK, and whose Honorary Chair was Glenn Seaborg, co-discoverer of plutonium and former Chair of the US AEC, stated "We are aware that a number of well qualified scientists in countries that have not developed nuclear weapons question the weapons-usability of reactor-grade plutonium. While recognising that explosives have been produced from this material, many believe that this is a feat that can be accomplished only by an advanced nuclear weapon state such as the United States. This is not the case. Any nation or group capable of making a nuclear explosive from weapons-grade plutonium must be considered capable of making one from reactor-grade plutonium" (American Nuclear Society, "Protection and Management of Plutonium", Special Panel Report, 1995, p25). * In 1997, the US Department of Energy set out the most detailed information yet about the utility of reactor-grade plutonium for weapons. "At the lowest level of sophistication, a potential proliferating state or subnational group using designs and technologies no more sophisticated than those used in first generation nuclear weapons could build a nuclear weapon from reactor-grade plutonium that would have an assured, reliable yield of one or a few kilotons (and a probable yield significantly higher than that). At the other end of the spectrum, advanced nuclear weapons states......could produce weapons from reactor-grade plutonium having reliable explosive yields, weight and other characteristics generally comparable to those of weapons made from weapons-grade plutonium......Proliferating states of intermediate sophistication could produce weapons with assured yields substantially higher than the kiloton range possible with a simple, first-generation nuclear device." and "The disadvantage of reactor-grade plutonium is not so much in the effectiveness of the nuclear weapons that can be made from it as in the increased complexity in designing, fabricating and handling them. The possibility that either a state or sub-national group would choose to use reactor-grade plutonium, should sufficient stocks of weapons-grade plutonium not be readily available, cannot be discounted. In short, reactor-grade plutonium is weapons-usable, whether by unsophisticated proliferators or by advanced nuclear weapon states. Theft of separated plutonium, whether weapons-grade or reactor-grade, would pose a grave security risk." (USDOE, 'Final Nonproliferation and Arms Control Assessment of Weapons-usable Fissile Material Storage and Excess Plutonium Disposition Alternatives', 1997 pp38-39). * The same USDOE report provided a firm rebuff to the Amarillo National Resource Center for Plutonium, one of the many bodies asked to comment on the report before it was published, which recognised that both weapons-grade and reactor-grade plutonium could be used in weapons but wished to include wording to the effect that weapons-grade plutonium was significantly more attractive. The report said "The Assessment has been reviewed and modified to ensure that the discussion of the value of weapons-grade and reactor-grade plutonium for use in weapons is consistent. It was not possible to adopt the recommended definition, since it includes subjective terminology (significantly more attractive). The Assessment concludes that reactor-grade plutonium could be used to construct both primitive and advanced, modern and reliable nuclear weapons." (USDOE, as above, p190). MOX and ProliferationA number of the reports mentioned above comment on the proliferation risks posed by the use of MOX fuel and in particular the recoverability of plutonium from such fuel. CISAC, for example, observe that "separating plutonium from other elements with which it might be mixed in fresh reactor fuel requires only straightforward chemical processing." (CISAC, as above). Whilst USDOE note, "Nevertheless, it is important to understand that fresh MOX fuel remains a material in the most sensitive safeguards category, because plutonium suitable for use in weapons could be separated from it relatively quickly and easily." (USDOE, as above, p84). This last point was also accepted by the UK Environment Agency which stated that "It would be a relatively straightforward matter to undertake chemical separation of plutonium from MOX fuel." (Environment Agency, "Document Containing the Agency's Proposed Decision on the Justification for the Plutonium Commissioning and Full Operation of the Mixed Oxide Fuel Plant, 1998, para A7.20). An independent technical evaluation undertaken in the US, for USDOE, looked at all aspects of proliferation risks associated with the disposition of excess weapons plutonium, including the burning of such plutonium in MOX fuel. Comprising 14 experts from the Sandia, Los Alamos and Lawrence Livermore National Laboratories and from Savannah River, and known as the Proliferation Vulnerability Red Team (PVRT), the evaluation concluded that "plutonium in weapons-useful quantities could be recovered from any of the forms in the disposition program. Furthermore the resources required for the recovery of a significant quantity of plutonium, including the manpower, materials, equipment and time would be relatively modest." (Proliferation Vulnerability Red Team Report, SAND97-8203, 1996 p4-1). The PVRT estimated the amount of resources and time that would be required to recover one Significant Quantity (SQ) of plutonium metal, that is 8 kgs as defined by the IAEA. For fresh MOX fuel, given proper preparation, recovery of one SQ of plutonium could be accomplished by only four skilled personnel over a six week timescale. Subsequent fabrication of a weapon would add only days to the estimate (PVRT, as above, p4-6). SafeguardsIt is clear that no international safeguards system can physically prevent diversion or the setting up of an undeclared or clandestine nuclear programme." (IAEA, 'Against the Spread of Nuclear Weapons: IAEA Safeguards in the 1990s', 1993) The IAEA's safeguards budget has been constrained for many years with member countries unwilling to provide additional resources even though the workload on the Agency has increased dramatically.For example, there was no real growth in the regular budget for safeguards between 1992 and 1996 and only marginal growth in staff resources for safeguards inspections despite the fact that the number of facilities under safeguards grew by 13% in that time and the total number of Significant Quantities under safeguards (mostly plutonium) grew by 43%. (IAEA Bulletin, Vol 39, No 4 1997). In a speech to a Conference on Global Nuclear Materials Management, in 1998, Piet de Klerk, Director of Policy Coordination at the IAEA lamented the fact that "These quantities of nuclear materials, however, combined with the increased numer of states that have full scope safeguards, with the implementation of our strenghtened safeguards system and its new equipment, our safeguards budget is bursting at its seams. For example, two-thirds of the new equipment that we need next year cannot be funded from our regular budget and will have to come from extrabudgetary sources." (CSIS, 'Global Nuclear Materials Management', Conference Report, Center for Strategic and International Studies, Washington, 1999 p65) The US General Accounting Office (GAO) has expressed concern about the ability of the IAEA to implement the 93+2 safeguards system introduced after the debacle in Iraq. "US officials are concerned about IAEA's safeguards goal attainment for unirradiated direct use material," it says and further notes that partly because of budgetary uncertainties, but also because some of the technology required to implement 93+2 is not proven, the IAEA "does not have a long term plan for implementing the new system." (GAO, 'Nuclear Nonproliferation Uncertainties with Implementing IAEA's Strenghtened Safeguards System', GAO/NSIAD/RCED-98-184). Meanwhile EURATOM, whose safeguards aims are more limited than those of the IAEA, finds itself facing similar pressures. A review of 40 years of EURATOM safeguards cites the expansion of the EU and implementation of 93+2 activities and stresses that "the complexity of the task facing EURATOM will increase as more large plutonium handling plants are commissioned or reach full throughput. And all of this needs to be accomplished with ever tightening constraints on the necessary human and financial resources." (Benavides P, 'Safeguards and Non-proliferation in the EU: Reflections on 40 Years of EURATOM Safeguards and Some Thoughts Concerning Future Developments', EC, Brussels, 1997). Both the CISAC and ANS Panel reports referred to above, recommended that separated plutonium should be protected as rigorously as nuclear weapons are. Current international standards, however, fall far short of this objective. There are no mandatory standards for the security of weapons-usable materials and no means whereby the international community can confirm areas of weakness. Security and accounting practices differ widely from country to country and although the IAEA has issued more detailed guidelines for the physical protection of nuclear materials these are advisory only. ConclusionsThe technology required to produce nuclear weapons dates back to the 1940s and the basic concepts involved are widely known. Much of the relevant physics is openly published and production equipment is largely dual use and readily available. Modern desktop computers are more powerful than those used to design nuclear weapons in the 1970s (when most current US weapons, for example, were designed) and it has been amply demonstrated that reactor-grade plutonium is weapons-usable. Although the technical challenges should not be underestimated, it is clear that the major barrier to the proliferation of nuclear weapons today is access to fissile material. Plutonium separation and reuse threatens both to put fissile material within reach of those, be they states or sub-national groups, who might desire it and to overwhelm an already stretched and underfunded safeguards system. Ensuring that all weapons-usable nuclear material worldwide is secure and accounted for is a fundamental nonproliferation priority. Further ReadingSubmission
to the 1st Round of Consultation on the Sellafield MOX Plant, CND, 1997.
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