MIMAS, setting the world-wide standard for plutonium recycling

Deployment of MIMAS MOX fuel irradiation started in 1985 with loading and irradiation in French 900 MWe PWR of EDF. A 20-year comprehensive R and D programme preceded it. This success was greatly facilitated by some early strategy advantages: 1) Development and licensing of a 'UO2-like' MOX fuel rod fully interchangeable with UO2 rods; 2) Joint SCK/BN operation of the BR2 (MTR) and BR3 (PWR) reactors, pilot and industrial MOX fuel plants, PIE hot laboratories in the Mol/Dessel site. The period since 1985 saw the occurrence of some concurrent facts, that have incontestably led MIMAS to the world-wide leader position (99 % of actual MOX fuel is MIMAS): 1) BN-MIMAS has been selected by Cogema for its plants MELOX and Cadarache and has demonstrated to be a flexible, scalable, and industrial process. 2) MIMAS has been further selected by JNFL for its Japanese domestic MOX plant (Rokkasho-mura) and by US-DOE for its domestic MOX plant (Savannah-NC) for the disposition of 34-ton weapon-Pu. 3) Satisfactory fabrication and irradiation over 1840 metric tons of MIMAS MOX fuel. In order to face the worldwide on-going electricity market liberalisation, MIMAS makers and vendors must definitely improve the MOX performances to compete with continuously improving UO2 fuel. The facing of this continuous challenge is also reviewed in the paper. (authors)