The use of reprocessed fuel is established: more than 30 years of using MOX and ERU fuel assemblies in LWR

The optimum use of fuel has been an important goal for operating light water reactors all times. This is becoming more important by the price for natural uranium keeps rising. During the last 30 years, AREVA - in cooperation with its customers - has already made a noteable contribution to this by reprocessing depleted fuel assemblies and by recycling fuel. The plutonium extracted at reprocessing is returned to the fuel cycle as MOX fuel assemblies. By mid 2006 more than 4,000 MOX fuel assemblies were inserted into 35 European PWRs and more than 700 MOX fuel assemblies were loaded into 2 European BWRs. Apart from a few exceptions all these fuel assemblies were designed and manufactured by AREVA. In 1986 Belgo-Nucleaire introduced the MIMAS Process for the manufacturing, a process which is still being used. MOX fuel assemblies present a high reliability, comparable to UO2 fuel assemblies. This also applies to the so-called ERU (Enriched Reprocessed Uranium) fuel assembly, being used for years to return uranium extracted at reprocessing back into the fuel cycle. By mid 2006 in total about 1,800 ERU fuel assemblies were loaded into 15 European PWRs in six different countries and more than 400 ERU fuel assemblies were loaded into 2 European BWRs in two different countries; all of which were designed by AREVA. The requested U-235 concentration was partly met by the usual process of enrichment during the gas-phase using centrifuges and partly by mixing the reprocessed uranium with medium- or highly enriched uranium. Regarding ERU, assemblies have reached a burnup of over 50 MWd/kgU. MOX fuel assemblies could even reach 60 MWd/kgHM in some cases. (orig.)