Minimization of actinide waste by multi-recycling of thoriated fuels in the EPR reactor

S.J. Rose^1a, J.N. Wilson², N. Capellan², S. David², P. Guillemin³, E. Ivanov⁴, O. Méplan³, A. Nuttin³ and S. Siem¹

¹ University of Oslo, Department of Physics, P.O. Box 1048, Blindern 0316 Oslo, Norway
² Institut de Physique Nucléaire d'Orsay, Bât 100, 15 rue G. Clémenceau, 91406 Orsay cedex, France
³ Laboratoire de Physique Subatomique et Cosmologie, 53 rue des Martyrs, 38026 Grenoble, France
⁴ Institut de Radioprotection et de Sûreté ; Nucléaire 31, ave. de la Division Leclerc, 92260 Fontenay-aux-Roses, France

^a e-mail: sunniva.rose@fys.uio.no

Published online: 14 February 2012

Abstract

The multi-recycling of innovative uranium/thorium oxide fuels for use in the European Pressurized water Reactor (EPR) has been investigated. If increasing quantities of ²³⁸U, the fertile isotope in standard UO₂ fuel, are replaced by ²³²Th, then a greater yield of new fissile material (²³³U) is produced during the cycle than would otherwise be the case. This leads to economies of natural uranium of around 45% if the uranium in the spent fuel is multi-recycled. In addition we show that minor actinide and plutonium waste inventories are reduced and hence waste radio-toxicities and decay heats are up to a factor of 20 lower after 10³ years. Two innovative fuel types named S90 and S20, ThO₂ mixed with 90% and 20% enriched UO2 respectively, are compared as an alternative to standard uranium oxide (UOX) and uranium/plutonium mixed oxide (MOX) fuels at the longest EPR fuel discharge burn-ups of 65 GWd/t. Fissile and waste inventories are examined, waste radio-toxicities and decay heats are extracted and safety feedback coefficients are calculated.