Thermal recycling of plutonium and uranium in the Federal Republic of Germany: Strategy and current status

The Federal Republic of Germany decided to close the nuclear fuel cycle by reprocessing. The proposed recycle strategy uses MOX fuel assemblies to recycle the plutonium, preferably with reprocessed uranium (RU) as the carrier material. The remaining RU is enriched separately and used for enriched RU (ERU) fuel assemblies. In 1980 the Federal German utilities decided to pool their plutonium resources. In co-operation with Kraftwerk Union (KWU) and Alpha Chemie and Metallurgie (ALKEM), it was decided that plutonium which could not be used in FBRs should be used for thermal recycling. The technical feasibility and the economic use of plutonium have thereby been proved, primarily for PWRs. The programme is scheduled to be extended to include BWRs in order to increase the recycle capacity. No technical problems have arisen in the design and use of the ERU fuel assemblies. The experience gained with the recycling of plutonium and uranium is based on programmes which, to a greater extent, have been performed on a commercial basis. Since 1966 a total of about 25,000 MOX fuel rods containing up to 3.5 wt% Pufiss have been inserted in 277 MOX fuel assemblies. To date, MOX fuel assemblies of KWU design, the fuel rods of which were fabricated by ALKEM, have been inserted into the Kraftwerk Obrigheim, Kernkraftwerk Neckarwestheim (GKN) Unit 1, Beznau-2 (Switzerland), Kernkraftwerk Unterweser and Kernkraftwerk Grafenrheinfeld. In 1986, ERU fuel assemblies (currently 820 fuel rods) were loaded at GKN-1. The plutonium and uranium recycling described shows that thermal recycling is feasible on an industrial scale and that common levels of reliability and safety can be achieved in reactor operation. (author). 3 refs, 4 figs, 1 tab