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Briefings & Information Mixed Oxide Fuel (MOX): What is it?Some answers to some questions MOX is an abbreviation for a mixture of uranium and plutonium oxides that can be used as fuel in nuclear reactors. The ultimate objective of the nuclear industry was to use plutonium that is extracted from spent fuel in reprocessing plants as a fuel for Fast Breeder Reactors (FBR). However, the FBR project has failed in every country that has experimented with it because of technical difficulties in maintaining safety and control, and the high economic costs of overcoming these technical problems. Consequently, the countries that have pursued this path now have large plutonium stockpiles because of reprocessing contracts that were agreed more than twenty years ago. In order to use some of the plutonium already extracted through reprocessing and the plutonium accumulating in spent fuel awaiting reprocessing, BNFL is proposing that their contracting utilities accept it back in the form of MOX fuel for use in conventional light water reactors (LWR). Originally, this was meant to be a bridging programme, designed to fill the time and technical gap that was occurring in the FBR programme. However, now that the FBR programme has virtually collapsed, its advocates see the MOX programme as the saviour of the plutonium economy. Currently, France, Germany, Belgium, Switzerland, Netherlands, UK and Japan are the main countries involved in the MOX programme. British Nuclear Fuels and MOX - what are they up to?Currently BNFL have a MOX Demonstration Facility (MDF) at Sellafield that has been in operation for the last three years. It produces around 7-8 metric tonnes of MOX each year mainly for a Swiss client. The much larger Sellafield MOX fabrication Plant (SMP) is nearing completion and BNFL hope to start producing around 120 tonnes of MOX a year starting in 1998. None of the British nuclear power plant operators intends to use MOX as fuel for their nuclear reactors. British Energy said in a statement recently that:
They have also said that they have no plans at present to use this expensive fuel source at the PWR reactor at Sizewell. Therefore, BNFL's potential market for MOX fuel is overseas although they have refused to divulge any information about contractual arrangements for reasons of 'commercial confidentiality'. BNFL Inc. has formed a partnership known as MOX-USA with Babcock & Wilcox, Bechtel National Inc., and Westinghouse Inc. in an attempt to win the contract to convert surplus plutonium from US nuclear weapons into MOX fuel. BNFL is also instrumental in promoting similar usage of Russian plutonium from dismantled nuclear weapons in civil nuclear reactors. Why is MOX being promoted by BNFL?It is estimated that if THORP operates as planned then there will be a stockpile of some 60-65 tonnes of reactor-grade plutonium in store at Sellafield. By 2010 this stockpile could increase to 90 tonnes. The current Sellafield civil plutonium stockpile from the MAGNOX programme has already produced over 40 tonnes (40,000 kilograms), sufficient to manufacture up to ten thousand nuclear bombs. BNFL is suggesting that MOX is an ideal way to reduce the plutonium stockpile they currently hold, and will continue to produce through MAGNOX reprocessing and THORP. BNFL also see MOX as a way of returning customer plutonium back to the country of origin in a safe and uncontroversial form for the generation of electricity. They intend to make money from the fabrication of MOX and later on from the storage or reprocessing of spent MOX fuel. What is wrong with MOX?CND's principal concern is that plutonium is presently being promoted by BNFL as a valuable energy resource that can easily be shipped all over the world and burned in nuclear reactors through its incorporation into MOX. Plutonium is not a valuable energy resource; it is one of the deadliest substances on the planet. A material so deadly that the smallest amount if ingested can cause cancer. It is also an essential ingredient in nuclear explosive devices. Any type of plutonium, be it weapons-grade (normally used in nuclear weapons) or reactor-grade (normally produced after reprocessing spent fuel rods from civil reactors) can be used to fabricate a nuclear explosive device. BNFL's plans to promote and sell MOX would help spread plutonium in an easily retrievable and usable form all over the world. Such a plan would not ensure that an essential ingredient for nuclear weapons remains under strict and effective international control. It will not help to reduce the ever-increasing amounts of plutonium stockpiled in the UK because of a continued commitment to nuclear reprocessing. Instead, it will merely turn the plutonium from one form (oxide) into another (MOX) and produce more plutonium in the process of irradiation in nuclear reactors. Can plutonium be easily separated from MOX?Yes. It is a relatively simple laboratory process. It is less complicated than the chemical processes that cocaine and heroine producers use to manufacture their products.One has to remember that MOX is merely plutonium and uranium blended and held in ceramic form. MOX can be dissolved and the two elements separated out, one of which is heavier than the other. What about international safeguards?There is no effective way of accounting for all the materials that go into and come out of any large-scale chemical or manufacturing process. Plutonium production through reprocessing is by no means unique in this respect, however, the potential consequences of any theft are as follows: Reprocessing relies heavily on estimates as the main safeguard against theft. To begin with, even the amount of plutonium present in each fuel rod is an estimate. Estimates are made on natural wastage inside the plant and to the environment and on how much plutonium should ensue. Actual amounts are recorded and balanced against original estimates. If there is less plutonium than expected, this can be explained by a number of reasons. Disturbingly, no-one can say with any degree of certainty that the missing material ever actually existed, whether it is still inside the system, whether it has been discharged as nuclear waste or even whether it has been stolen. This is not a hypothetical question for academics. In the last twenty-five years, Sellafield has theoretically lost an estimated 80 kilograms of plutonium. Enough to produce 10 to 20 nuclear bombs. Similar rules apply to MOX production. A large-scale commercial plant producing MOX will have in the system at any one time hundreds of kilograms of plutonium. Diversion of small amounts of plutonium over a period of time by a seemingly trustworthy employee who has been bribed, blackmailed or seduced cannot be entirely ruled out. At the Plutonium Fuel Production Facility in Tokai, Japan, it was discovered that 70 kilograms of plutonium was retained within the plant, after there was a major scare about the scale of error between what went into the plant and what came out. Large-scale MOX production and export will naturally result in much increased transportation all over the world. Anyone wishing to illegally manufacture a nuclear explosive device would view the time between the MOX leaving the supplier and it reaching the customer as being the most vulnerable point in the entire cycle. The relative ease with which MOX can be separated into its two component parts means that any physical security measures surrounding MOX transportation should be similar to those used to guard nuclear weapons in order to reduce the risk of theft. There is also the problem of when the customer takes charge of the MOX. Fuel assemblies can be diverted and replaced before being placed in the nuclear reactor. Cameras can be blocked and obscured, records can be altered and by the time anyone finds out what has happened it could be too late. The international safeguards regime is already understaffed and overworked without being presented with the intolerable task of monitoring MOX fuel usage. Regardless of whether one is for or against nuclear power, everyone should at least agree that the production and export of MOX is a very risky business. Reprocessing of spent fuel to extract plutonium which is then used in the manufacture of MOX merely makes plutonium that much more accessible to many more people. Plutonium should be left in secure storage in central locations or remain in the spent fuel rod in dry stores where it cannot be extracted without the construction of a large-scale reprocessing plant which would hardly go unnoticed by the international community. Can any isotope of plutonium be used to produce a nuclear bomb?Yes, the evidence for this is overwhelming.
What are the alternatives for reducing the plutonium stockpile andreturning it to its owners?The obvious place to go for the answer to this question is the United States. The US has just drawn up a plutonium disposition policy to dispose of 50,000 kilograms of surplus plutonium from old nuclear weapons. The US proposes to use some of it in the production of MOX, the remainder would be immobilised either in glass (vitrified) or in ceramics. The exact amount to be used in MOX or to be immobilised has not yet been decided. The $2 billion US programme is the end result of years of debate on how to dispose of American surplus plutonium. Many methods were looked at, studied, and discussed in great depth. There remain many problems to be overcome with the least publicly popular option in the US of using MOX in civil nuclear reactors and the future of the US MOX programme is by no means certain. Vitrification is, however, a well-established technology. It is used in Britain, France, Germany, Belgium and Japan to prepare High-Level Nuclear Waste for return to BNFL's customers where it can be placed in interim storage until long-term disposal options can be found. This nuclear waste is mixed with borosilicate glass and turned into glass logs. BNFL are world leaders in this type of technology and have a plant currently in operation at Sellafield. As BNFL themselves say vitrification "is considered internationally as the optimum method for converting high-level liquid waste into a solid form which can be stored safely, conveniently and economically, and which is suitable for eventual transport and disposal." Glass or ceramics?The main difference between glass and ceramic immobilization is the matrix that contains the Pu [plutonium] (in the small cans). For glass CIC (can-in-canister), Pu would be immobilized in a borosilicate matrix, while the ceramic CIC would immobilize the PU in a titanate-based ceramic matrix. However, the conversion process used to produce the PU oxide would be the same regardless of the immobilization technology used. This step involves removing the surplus Pu from storage, converting it to a suitable oxide form, packaging it, and transferring it to either the glass or ceramic immobilization facility. Also, all steps after the small cans are prepared are the same for both glass and ceramic immobilization. Under the glass immobilization approach, in a process known as vitrification, the Pu oxide would be fed into a melter along with small glass pebbles (known as "frit") and neutron-absorbing materials to ensure that no accidental chain reaction could occur long after being placed in a geologic repository. This step would produce a homogeneous borosilicate glass with the Pu and neutron absorbers dissolved within it which would be poured into small cans. Under the ceramic immobilization approach, after mixing and initial heating, the ceramic material, Pu oxide, and neutron absorbers would be "cold pressed" to compact the mixture as much as possible without heat, and then baked ("sintered") to produce densified pellets which would be loaded into small cans. This cold-pressing process offers greater simplicity and greater throughput, and is nearly identical to the processes used to produce sintered pellets for mixed oxide (MOX) fuel. Despite this opinion BNFL has not utilised their expertise in this area to examine ways in which vitrification technology could be used to contain and control the world's plutonium stockpiles. Plutonium, as far as BNFL are concerned, is an invaluable resource that should not be discarded. The US opinion is quite different.
The US also found that "the lowest cost option for plutonium disposition would be immobilization…" Whether the MOX option is taken up by the US remains to be seen as there is a proviso in the decision that whilst not all of the surplus plutonium can be used in the production of MOX they may decide to utilise vitrification or ceramic immobilisation to dispose of all their surplus stocks. If the Americans are planning to use MOX why shouldn't we?The US plutonium disposition policy is very different from Britain's. Firstly, they actually have one. Secondly, there is no absolute guarantee that MOX will end up being used as a disposal method, it is still a proposal. Immobilisation in either glass or ceramics will, however, be used for some if not all the excess US plutonium.
Thirdly, if the MOX option is adopted it will be contained within the North American continent. Only US plutonium will be used and it is proposed that domestic or Canadian nuclear power plants will burn it (recent information indicates that the Canadian option is most unlikely). The US does not intend to sell MOX around the world in the way BNFL are currently proposing. Fourthly, it appears from the US Department of Energy Record of Decision that MOX was chosen for principally international political rather than scientific or technical reasons. What should Britain be doing?What the Americans have spent the last several years doing - drafting and agreeing a 'Plutonium Disposition Policy'. The US first drafted a very simple criterion that had to be met before any method was chosen for disposing of their plutonium stockpiles. Each method chosen had to meet the 'Spent Fuel Standard' i.e. the raw plutonium has to be as inaccessible as it is when it is locked inside a spent nuclear fuel rod.
They then spent years examining all the different possible methods. In addition, there was wide-scale public consultation as well before a decision was arrived at. The Foreign Office should take the lead, with the full co-operation of the MoD, the Atomic Weapons Establishments, the Department of Trade and Industry and the Environment Agency in drafting a 'Plutonium Disposition Policy' for Britain. Every option should be considered. The issue should be publicly and openly discussed as part of an extensive consultation process. No aspect or technology should be ignored. Rather than leaving it up to BNFL (who are ultimately only in the MOX business to make money) the British government should draft a 'Plutonium Disposition Policy' that will ensure as far as physically possible that this deadly material cannot fall into the wrong hands at some point in the future. |
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