Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Depleted uranium tails and uranium residues from reprocessing

The objectives of the study are to:
determine the quantities and rates of accumulation of depleted uranium tails and arising from enrichment of natural uranium (and uranium recovered in the reprocessing of spent fuel) in the past and the foreseeable future (until about the year 2010);
allocate these data to the storage facilities currently in existence;
characterize the substances with respect to their chemical, physical, and radiological properties, identify and quantify possible ways to use and/or to dispose of these quantities.

Basic data which has been collected for reprocessed uranium U(re), comprise: product specification, homogeneity, current inventories and accumulated arising to the year 2010, storage capacities, storage times, product characteristics and transport requirements.

Major composition differences exist between U(re) and natural uranium, U(nat). U(re) can be contaminated with transuranics (neptunium and plutonium), fission products (ruthenium and technetium) and minor uranium isotopes. The latter include uranium-232, which produces the high energy gamma emitter thallium-208, and uranium-236, a strong neutron absorber, needing increased uranium-235 enrichment to compensate, and finally uranium-234, a very alpha active isotope, necessitating lower ingestion limits and stricter containment. Thus, decisions on prolonged storage and early recycle will be influenced by the above data. Detailed data on the uranium isotopes in fuel with varying enrichment, burn-ups and cooling times have been collected. All the data collected will be used in the consideration of use and/or disposal of U(re), on which subject much of the available information has been assembled.

Uranium tails from both enrichment of natural uranium and enrichment of U(re) are generated in the reference enrichment plants in the Netherlands, Federal Republic of Germany and the United Kingdom, all of which are operating under the international consortium Urenco Ltd. The position of the tails in the nuclear fuel cycle has been studied. Also the effect of the degree of enrichment and storage times on the isotopic composition of uranium in the spent fuel have been investigated, particularly the concentrations of the 2 isotopes of concern uranium-232 and uranium-234, in relation to the future use or disposal of U(re) tails. Little of the transuranics, or fission products are found to remain in the tails.

Relevant operating data for plants have been collected, together with data on both types of tails, including, material specifications, inventories, annual arising, accumulated stocks, storage capacities and transport requirements.

Contatto

Hans-Joerg WINGENDER, (Head of Department)
Tel.: +49-6023-911432
Fax: +49-6023-911660
E-mail