The CONVERSION as soon as practicable OF HIGHLY ENRICHED URANIUM (HEU) extracted from nuclear weapons resulting from the reduction of nuclear weapons pursuant to arms control agreements and other commitments of the parties which is currently estimated at approximately 500 metric tons in the Russian Federation, having an average assay of 90 percent or greater of the uranium isotope 235 INTO LOW ENRICHED URANIUM (LEU) for use as fuel in commercial nuclear reactors
http://www.nti.org/db/nisprofs/russia/fulltext/heudeal/heufu...

Thus the CONVERSION FROM HIGH-ENRICHED TO LOW-ENRICHED URANIUM will be a fact, and after several years a process of technical development, ...
www.nrg.eu/general/nieuws/2006/20060508.html

HIGHLY ENRICHED URANIUM RECYCLE AND CONVERSION FACILITY at COGEMA Pierrelatte. S. Bouchardy * and J. F. Pauty. COMEGA, Uranium Division, 78140 Velizy ...
ENRICHED URANIUM inventories (over 5% U235) exist under various chemical forms and enrichments. The REUSE OF THESE MATERIALS FOR RESEARCH REACTOR FUEL, EXPERIMENTAL REACTORS OR AS RAW MATERIAL FOR RESEARCH LABORATORIES REQUIRES A CHANGE IN THE CHEMICAL FORM AND/OR A CHANGE IN THE ENRICHMENT LEVEL and/or an improvement in the chemical purity. The COGEMA PIERRELATTE FACILITY (RECYCLE AND CONVERSION FACILITY) is well suited to perform these tasks. Its experience in this field has been acquired over the last 30 years. This paper presents the capabilities of this facility.
linkinghub.elsevier.com/retrieve/pii/S0029549397002100

In which case you'd best stick to "treated uranium" and let the readers' fingers do the walking.

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Note added at 1 hr (2010-11-03 09:56:49 GMT)
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COGEMA Pierrelatte a pour activités principales la conversion en oxyde du nitrate d'uranyle issu du traitement des combustibles usés et la défluoration des uraniums appauvris issus de l'enrichissement.
Pour le compte du Commissariat à l'Energie Atomique, COGEMA assure le démantèlement des usines qui ont produit pour les besoin de la Défense nationale de l'uranium très enrichi, jusqu'en 1996.
http://www.office-tourisme-pierrelatte.com/vieeco-detail.php...

OK, so once spent fuel has been TREATED and de-enriched uranium has been DEFLUORATED, there remains a waste product requiring CONVERSION into uranyl nitrate oxide ...

On March 16, 2002, a 200-litre tank of low-level liquid radioactive waste exploded at Cogéma's Pierrelatte TU5 CONVERSION facility. An investigation done by ...
www.wise-uranium.org › ... › Issues › Europe

Uranium and plutonium recovered by spent fuel reprocessing are recycled into new fuel elements at Pierrelatte. COGEMA has two facilities in operation (TU2 (17) and TU5 (18) ) to chemically treat recovered uranium for recycling into uranium fuel, after reenrichment in uranium 235. TU2 also produces depleted uranium oxide for mixed uranium / plutonium oxide fuel (MOX).
http://www.globalsecurity.org/wmd/world/france/pierrelatte.h...
Here spent fuel is processed to produce uranium and plutonium which are then recycled (converted?) to make new fuel.