The Future for Excess Weapons Grade Plutonium ?

At the occasion of the dinner-debate, Bennett Johnston, former US Senator and former Chairman of the Committee on Energy and Natural Resources, and Evgeny Kudriatsev, responsible for international co-operation projects on plutonium in the Russian Minatom, presented their views on the future use of weapon-grade plutonium.

As a result of the nuclear disarmament process (START 1 and START 2 Treaties), hundreds of tons of resulting weapon-origin materials become available for peaceful use. This material includes weapon-grade Plutonium (W-Pu) and highly enriched Uranium (HEU). The dinner-debate concentrated on the W-Pu, about which a French-German-Russian initiative was notably announced in Paris, in October 1996.

The Russian position

Mr Kudriatsev explained that in Russia, Plutonium is not considered as a waste, but as a valuable material and energy source. Therefore the Russian government has always supported a MOX-fuel option for using plutonium from dismantled weapons, which offer many advantages, notably from a non proliferation standpoint :
• high radioactivity of the final product, a spent MOX fuel assembly
• fission of a significant fraction of the initial W-Pu
• plutonium accountancy : the W-Pu is processed in a set of industrial facilities under permanent surveillance by international organisations (like the IAEA)
• isotopic denaturing of the residual plutonium
• no additional nuclear waste (e.g. vitrified plutonium) : the spent MOX fuel assembly replaces a spent uranium fuel assembly.

Since France and Germany accumulated industrial-scale experience in Pu fuel production and reactor use, both countries began to co-operate with Russia on a MOX fuel option. From 1993, a wide range of bilateral research and design studies of W-Pu peaceful use have been performed under the French-Russian “AIDA-MOX” programme. The studies have demonstrated the feasibility of W-Pu utilisation in commercial MOX fuel with the use of already existing industrial technology and equipment.

A trilateral French-German-Russian initiative was announced at an Experts Meeting in Paris (October 1996) : COGEMA and SIEMENS announced a joint project called DEMOX, with MINATOM of Russia, to set up a basis for the processing of at least 1300 kg W-Pu per year from the year 2001 and loading of the produced MOX-fuel into Russian BN-600 unit and 4 VVER-1000 reactors (30 MT MOX per year).

The design of the MOX-plant would be based on the results of bilateral projects with optimum use of the German Hanau plant equipment and the French Cadarache and Melox plant technological and operational experiences, particularly the advanced MIMAS process.
The pre-commercial phase of the project would include basic design, cost estimate, draft of a quotation and financing models. It is expected that construction of the DEMOX plant will allow the start up of the plant in 2002. The possibility of progressive extension of the plant will be investigated, with a capacity of about 5 MT of W-Pu per year.

The US position

Senator Bennett Johnston indicated that the USA would follow a dual track approach, following the release in January 1997 by the Department of Energy (DOE) of its “Record of decision” which called for a hybrid plan for disposal. On the one hand, it proposed to immobilize at least 8 tons of plutonium unsuitable for recycling in glass or ceramics and bury it underground. On the other hand, it proposed to burn a quantity of plutonium (in the form of MOX fuel) as yet undetermined, in existing light water reactors or Candu reactors. The construction of a MOX fuel facility, at a location in the United States still to be decided, would be required.

According to him, burning plutonium as MOX fuel has strong advantages over immobilisation from a proliferation standpoint. Indeed, the plutonium is degraded at the atomic level to be practically unsuitable for weapons. This is contrasted to the “can in canister” method, the currently preferred immobilisation technique, which does not degrade the plutonium. Moreover, much of the plutonium is consumed in the MOX burning process.

The ensuing discussion gave the opportunity to recall to the participants the considerable and unique experience accumulated by the European Union and Switzerland in fabricating and using MOX fuel in nuclear power plants.

As of mid-1998, 28 European nuclear power plants have been loaded with MOX : 14 in France, 9 in Germany, 3 in Switzerland and 2 in Belgium. Another two other reactors should be loaded soon in France ; 42 to 48 reactors should be loaded with MOX in Europe at the beginning of the next century. As of the end of 1997, 650 tonnes of MOX fuel have been loaded, representing the recycling of 30 tonnes of plutonium (excluding fuel for fast reactors).