UF6 at a medium or high level of enrichment is ordinarily converted into metal. The dry method or the wet method can be used. The dry method includes the reduction of UF6 to UF4 by hydrogen in great excess. The stages of the wet method, like that used by Cogéma at the Unité de récupération et d’élaboration des lingots d’uranium (URE) of Pierrelatte, consists in treating UF6 with steam and obtaining successively UO2F2, uranium salts, ammonia diuranate, UO3 and UO4. The UF4 is transformed into metal by metallothermic reduction with magnesium or calcium.

In France, conversion of highly enriched uranium to metal for military use took place or takes place in URE. Today URE carries out civilian projects. In addition, Cerca offers its clients conversion of UF6 into uranium metal for all levels of enrichment.

Moreover, UF6 enriched to more than 5% uranium 235 was converted into UO2 at Cadarache (at the Atelier de traitement de l’uranium enrichi [ATUe] and possibly at Technicatome) and perhaps at Bollène and Saclay. We do not know what installation carries out this procedure today or even if uranium oxide with more than 5% uranium 235 is still produced.

UF6 enriched to about 3.5% uranium 235 for use in PWRs and BWRs (standard or Repu) is transported in solid form to a fuel fabrication facility where the UF6 is vaporized and then converted into UO2 (see Fuel fabrication).

Depleted UF6 can be transformed into metal by the wet method or the dry method, followed by metallothermic reduction with magnesium or calcium.

The Comurhex plant at Pierrelatte has transformed, and perhaps still transforms, depleted UF6 into UF4 by the dry method while the Comurhex plant in Malvési transformed UF4 into metal. The former TU3 facility of Cogéma at Pierrelatte likewise transformed UF6 into UF4 for conversion into metal at Malvési.

Depleted UF6 can be transformed into UO2 for use in Mox fuel for fast breeder reactors or for pressurized water reactors. The ATUe shop at Cadarache carried out this conversion by the dry method and the wet method. Cogéma’s TU2 workshop at Pierrelatte produces UO2 for Mox fuel for pressurized water reactors, but we do not know if TU2 receives for this purpose UF6 or uranyl nitrate.

In France depleted UF6 is also converted to U308 for storage. This conversion takes place in plant W at Pierrelatte. The process is described in the section on Tricastin/Pierrelatte. Part of the U308 from Usine W is transformed into uranyl nitrate at Malvési for dispatch to Tu2 [Bladier 01].