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Nuclear Control Institute

Washington, DC


July 17, 2000




At the U.S.-Russian summit this June, Presidents Clinton and Putin agreed in principle on a framework for the disposal of 34 tonnes each of plutonium withdrawn from nuclear weapons programs.  According to the U.S. Government, the agreement (which has not yet been signed) stipulates that 25 tonnes of weapons-grade plutonium in the U.S. and 34 tonnes of weapons-grade plutonium in Russia would be incorporated into plutonium-uranium mixed-oxide fuel (“MOX”) and irradiated in existing reactors. 


The United States plans to load MOX into four commercial pressurized-water reactors (PWRs) owned by Duke Power and located in North and South Carolina.  Russia plans to load MOX into some combination of seven VVER-1000 reactors (four located at Balakovo, two at Kalinin, and one at Novovoronezh), as well as the BN-600 fast breeder reactor at Byeloyarsk and the BOR-60, a small breeder in Dimitrivograd.  The MOX fuel would be substituted for a fraction of the enriched uranium that normally fuels the reactors.  The remaining 9 tonnes of U.S. weapons plutonium would be combined with high-level nuclear wastes after being stabilized in a ceramic matrix, through a process known as immobilization.  The Russian Government considers plutonium a valuable resource, and so far has not agreed to dispose of any weapons plutonium by means of immobilization.


The G-8 Role in Plutonium Disposition


            At the April 1996 summit in Moscow, the G-8 expressed their support in principle for U.S.-Russian weapons plutonium disposition, but did not commit to provide financial or other support for these efforts.


            In their July 13, 2000 joint statement, the G-8 foreign ministers pledged “to cooperate to establish multilateral arrangements necessary for a coordinated and integrated program for the safe management and disposition of weapon grade plutonium no longer required for defense purposes, and call on other states to join us in supporting this effort.”  However, the ministers did not make any financial commitments to pay for this effort.  According to a senior Clinton Administration official, the U.S. and Russian governments hope to use the heads of state summit this week “to begin to put together an international funding mechanism” for plutonium disposition in Russia.  Specifically, the G-8 may be asked to help finance construction of a MOX-fuel fabrication plant in Russia, with specific consideration of the export of equipment from a MOX plant that was constructed in Hanau, Germany.  The Hanau MOX plant was manufactured by Siemens for Germany’s nuclear-power program, but did not receive the necessary operating licenses from the German government and has never operated.


The MOX-Fuel Disposition Option is Dangerous


At the April 1996 nuclear safety and security summit in Moscow, the G-8 emphasized that “each state possessing fissile material designated as no longer required for defence purposes is responsible for its management, taking into account the need to avoid contributing to the risks of nuclear proliferation; the need to protect the environment; the resource value of the material and the costs and benefits involved.”  By any of these criteria, MOX fuel is an undesirable plutonium disposition option.


A major international commitment to finance MOX-fuel plutonium disposition in Russia is premature.  MOX fuel made from weapons plutonium has never been used on a commercial scale anywhere in the world.  MOX fuel made from plutonium recovered from used nuclear-power plant fuel is used on a limited basis in Western Europe and Japan, but the relevance of this experience to weapons-plutonium MOX is uncertain at best.  Small-scale test irradiations of weapons-grade MOX are underway, but the results will not be known for years.  Regulatory review of the MOX program has barely begun in either nation.


 According to a recent trade press report, the German government is “not prepared” to support the export of the Hanau MOX plant to Russia, nor does Berlin support turning Russian weapons plutonium into MOX.  [NuclearFuel, June 26, 2000]  Laura Holgate, the U.S. Department of Energy official in charge of the disposition program, stated that Russian MOX-fuel fabrication could not begin by the planned date 2007 without the export of the Hanau MOX plant.  The design and construction of an entirely new MOX plant could bottleneck the entire disposition program for years and drive up costs.

Reactors do not “burn up” the weapons plutonium in MOX fuel.  It is misleading to speak of "burning" weapons plutonium as if all or even most of the plutonium in MOX is consumed during irradiation. In fact, a full core of irradiated weapons-plutonium MOX fuel would contain only about 30 percent less plutonium than was contained in the fuel when it was loaded into the reactor. However, even these reductions won't be achieved in practice, because they would require reactors to be loaded entirely with MOX fuel. No light-water reactor anywhere in the world has been operated with a 100 percent MOX core. More realistically, a light-water reactor (LWR) loaded with a conventional one-third core of MOX fuel would discharge only about one percent less plutonium than was contained in the MOX fuel originally loaded.  The remaining 99 percent would remain usable in weapons if the spent MOX fuel were reprocessed (which Russia plans to do).

MOX-fuel plutonium disposition is extremely expensive.  A joint U.S.-Russian government study recently concluded that a MOX-fuel plutonium disposition program for Russia would cost up to $2.5 billion.  As large as this estimate is, it leaves out a number of expenses that are likely to drive up the price tag.  For example, every Russian VVER-1000 that is to irradiate MOX as part of the plutonium disposition program should be upgraded to Western safety standards.  A European Community study estimated that it would cost $120 to $180 million per unit to upgrade VVER-1000 reactors to Western safety standards.


Moreover, someone will have to pay for the continued operation of these reactors for the duration of the disposition program, which will take more than two decades to complete.  Moscow does not have the resources to do so.  Billions of dollars may well be required to underwrite the Russian nuclear power industry so that it can use MOX fuel.  The U.S. Department of Energy has repeatedly affirmed that MOX fuel is not economically viable in the United States for electricity production and is only being utilized for plutonium-disposition purposes.


MOX fuel would increase proliferation risks.  A MOX-fuel disposition program would provide Russia with the technical infrastructure to develop a plutonium fuel cycle for its civilian nuclear-power program.  Russia has explicitly retained the option to reprocess its irradiated weapons-plutonium MOX after the disposition program is completed.  This would defeat the entire purpose of the disposition exercise.  Once separated by reprocessing, the plutonium (still usable to make nuclear weapons though no longer “weapons-grade”) again becomes a proliferation risk.  Moscow has expressly reserved the right to use the MOX fuel-fabrication plant to manufacture civil MOX fuel after the negotiated bilateral disposition program is concluded.  Despite hopeful statements from the U.S. government, the Russian nuclear sector remains committed to the reprocessing of spent fuel and development of fast-breeder reactors.  While the BN-600 would be operated without a “blanket” so as not to breed more plutonium, it could be operated again in the future in breeder mode.  Russia continues to pursue funding for a new, larger fast breeder reactor, the BN-800.  The G-8 nations would in effect be subsidizing a future, and likely greater, proliferation threat.

Further, a Russian MOX program would present greater risks of diversion and theft of plutonium, primarily because of the fuel-fabrication stage, a process that is difficult to safeguard effectively, and because of the need to transport MOX fuel long distances to reactors. Uncertain verification could severely limit the trust nations place in an international nuclear arms reductions and nonproliferation regime. Hijacking of a MOX transport in Russia cannot be excluded, and weapons plutonium could be extracted from the fresh MOX fuel by straightforward chemical processes.

It is significant to note that safeguards and security issues related to Russia’s MOX program were not resolved in the recent U.S.-Russian agreement, but are to be the subject of future negotiations, the outcome of which is uncertain at best.


MOX fuel jeopardizes reactor safety.  Neither the United States nor Russia have had significant experience with MOX fuel in light-water reactors, the type of reactor used in commercial nuclear-power plants, and there is no experience anywhere with use of weapons-grade plutonium in MOX fuel.  Use of MOX fuel reduces the stability of reactor cores, so that operators have less time to respond and maintain safety in the case of rapid changes in the state of the reactor; increases the severity of certain accidents, such as those that cause a sudden cooling of the core; and increases the amount of certain extremely toxic radionuclides in the reactor core by a factor of two (in the case of a reactor with a 40% MOX, 60% uranium-fuel core).


A recent report by the Nuclear Control Institute analyzes a number of these issues.  The report calculates that in the event of a severe, Chernobyl-type accident with containment failure or bypass, at a U.S. PWR or Russian VVER-1000 reactor with a 40% MOX core, the number of latent cancer fatalities would be about 25% greater than for a similar reactor with an all-uranium core.  Depending on the population density in the vicinity of the accident, this could correspond to hundreds to thousands of additional cancer deaths.


            MOX-fuel liability issues remain unresolved.  A major sticking point in U.S.-Russian negotiations has been liability in case of a MOX accident.  Nuclear firms that might provide assistance to Russia’s MOX program would insist on indemnification in case of an accident.  However, neither the United States nor Russia has offered any guarantees in this regard.


The United States and Russia should take the all-important first step toward plutonium disposal of converting the metallic plutonium cores of dismantled weapons (known as "pits") into an intermediate, unclassified oxide form. They should work cooperatively to develop a mutually acceptable and verifiable technology for pit conversion, and to insure secure storage of the converted material. Conversion to oxide is required for both the MOX and immobilization approaches. Thus, this step should represent common ground on which Russia and the United States, as well as the other G-8 nations, can agree.

The G-8 nations should support efforts in both the United States and Russia to dispose of weapons plutonium directly as waste by immobilizing it with highly radioactive materials in a vitrified glass matrix.  Joint U.S.-Russian technical analyses, as well as studies by the U.S. National Academy of Sciences, have concluded that the immobilization approach is technically feasible and meets the “spent fuel standard” of making weapons plutonium as inaccessible for weapons use as is plutonium contained in spent fuel.

For More Information


Further information on plutonium disposition and the risks of MOX fuel are available on the Nuclear Control Institute website at  The following documents provide useful overviews:,,,,,


The Nuclear Control Institute (NCI) is a non-governmental organization based in Washington, DC, which focuses on the proliferation risks of nuclear materials (plutonium and highly enriched uranium).  Contact Steven Dolley, Nuclear Control Institute, (U.S.A) phone 202-822-8444; fax 202-452-0892; e-mail

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