Future UF6 usage in Russia

In Russia, the management of the Federal Agency for Nuclear Energy (Rosatom) esteems dumps of uranium hexafluoride exclusively as valuable power-producing raw materials which are not subject to burial. No common form of long-term storage of depleted uranium has been chosen yet. On the one hand, nuclear industry representatives state that uranium hexafluoride can be stored safely outdoors in standard containers up to 100 years. This contradicts the attitude of the Russian Federal Service for Ecological, Technical and Atomic Supervision (Rostechnadzor), which asserts that "storage of tanks with dump uranium hexafluoride at industrial sites does not meet the current safety requirements"..

On the other hand, FGUP "PO "Elektrochemichesky zavod", one of four Russian enterprises involved in uranium enrichment, purchased a French technology of transferal uranium hexafluoride in the oxide form.

Moreover, Rosatom, on the basis of the Angarsk Electrochemical Plant, carries out research work on studying technologies for transferral of DUF6 in the uranium tetrafluoride form (the so-called "Kedr" technology). It is necessary to mention that in France this storage form was not considered to be perspective.

In any case, safe long-term (within the first decades) storage requires uranium hexafluoride defluorization and its storage which Rosatom is concerned now about. S. Kiriyenko - a head of Rosatom, when answering the question about the destiny of the uranium hexafluoride dumps at the meeting with representatives of the Tomskaya Region community held in the Seversk City on April 12, 2006, answered like that: now we examine three variants of handling uranium hexafluoride waste, among which there are a "Cogema" company technology and a Russian technology. If we will not be able to solve the issue of utilization of depleted uranium hexafluoride "tailings", then I am ready to make a decision on cessation of importing foreign depleted uranium hexafluoride.

Possibility of depleted uranium usage in fast reactors

The issue of further usage of depleted uranium accumulated in Russia is a matter of principal, since the choice between storage and burial of depleted uranium depends on it. Among the methods of commercial use of depleted uranium, use in fast reactors is considered to be the most perspective one. Sometimes Rosatom representatives consider DUF6 to be the source of fluor acquisition for commercial use, which is not quite correct, since fluor is a by-product of the defluorization technology, and this method of its acquisition is more expensive, as compared with other methods of fluor acquisition.

In terms of use of depleted uranium in fast reactors, the thesis that all amount of defluorized depleted uranium received after conversion from DUF6 can be used as a matrix in mixed uranium-plutonium oxide fuel and in plutonium breeding blankets is beneath all criticism.

First, the large-scale implementation of fast reactors in Russia remains doubtful. The only operating industrial Russian power fast reactor BN-600 was launched in 1980. A lot of money and about 30 years have been spent for designing and constructing the next reactor BN-800. "The Strategy of Development of Nuclear Energy in Russia in the First Half of the 21st Century" stipulates mass construction of fast reactors only after 2030.

Besides cost and terms, there exists the unsolved problem of choosing the right and necessary technology of fast reactors. Thus, in Russia, an option of implementation of a standard reactor with lead coolant of the BREST type is under consideration.

Thus, it is too early to speak about a specific program of large-scale construction of fast reactors in Russia specifying their number and type, as well as more precise terms of their construction and placing into operation.

In France, similar construction programs for fast reactor construction were stopped due to economic and technical reasons.

Secondly, even assuming the plans for large-scale commissioning of fast reactors after 2030 to be realistic, these reactors will not be able to use promptly all DUF6 which is available and planned to be accumulated which will require its further storing. In 2000, the amount of accumulated DUF6 of Russian origin was estimated to exceed 700 thou. tons. About 125 thou. tons more are a product of processing uranium dumps imported from abroad upon contracts with West-European companies.

The accumulation rates of new DUF6 dumps are more than 4 thou t of DUF6/year which is due to accumulation of natural uranium extracted in Russia (with perspective for growth of extraction and enrichment). Moreover, there are possible further import of dumps from Western Europe and accumulation of DUF6 from foreign natural uranium (primarily, from Kazakhstan) within the framework of international projects on the basis of the Angarsk EChP to the extent of about 7,800 tons of DUF6 per year. New dumps will also appear as a result of enrichment of the natural component returned by USA upon the contract for sale of Russian weapon-grade uranium.

Considering these factors, by 2030 in Russia there will be additionally accumulated at least 200 thou. tons of DUF6. All together, by 2030 DUF6 stocks will make up to 1 mln tons of uranium hexafluoride containing more than 680 thou. tons of metallic uranium.

The annual loading by depleted uranium as part of charging fuel for BN-800 will be from 2.2 to 5.5 t U/year for annual loading by plutonium 0.6-1.7 t/year.

Much greater amount of depleted uranium can be used in blankets in the breeding zone. It has not been solved finally which amount of depleted uranium will be exposed in the breeding zone of BN-800 or Brest. But it is assumed that it will be about 100 tons of metallic equivalent of depleted uranium annually. It will take more than 6,800 reactor-years to spend 680 thou.tons of depleted uranium in this way. That means placing into operation of more than 220 reactors with useful life of 30 years, on the assumption of lack of recycling of irradiated fuel which is planned by Rosatom management. In case of a model for recycling of irradiated nuclear fuel and fast reactor blankets, the amount of reactor-years required for use of accumulated DUF6 will increase in accordance of the number of cycles of reusing irradiated uranium. Obviously, placing into operation of such amount of fast reactors is unrealistic. The highest pronounced figure of fast reactor amount planned to be placed into operation in Russia, was 60.

Duration of Utilization of 680 thou. tons of metallic uranium in BN-800 reactors

Even ignoring environmental aspects, safety issues and non-distribution of nuclear materials, and considering only time, technical and economic conditions, such way of utilizing 680 thou. tons of depleted uranium escaping after DUF6 conversion seem unrealistic. Thus, the overwhelming part of DUF6 will most likely need to be buried sooner or later.

The thesis that accumulated DUF6 is rather waste than raw materials appears in statements of nuclear scientists. Thus, G.Grigoryev, Deputy Director of the Institute for Molecular Physics of the "Kurchatovsky Institute" Russian Scientific Center said that the Angarsk EChP the profile of which is uranium enrichment "should have no other waste besides that produced by enrichment which has ever been there".

Special attention should be paid to the issue of reimbursement of expenses for DUF6 utilization (at least for defluorization) through possible commercial realization of depleted uranium for fast reactors. The Rosatom practice clearly shows that the cost of this uranium for fast neutron-based nuclear power will be zero or almost zero. This could be concluded upon the basis of the existing practice of storage of plutonium for fast reactors. Currently, about 50 tons plutonium for fast reactors is stored at enterprises of Rosatom, and Rosenergoatom Concern, the future user of this plutonium bears no expenses for storage of this "most valuable" energy resources, for instance funds for construction of the central storage for this plutonium were allocated by the United States.