Thoria and inert matrix fuels for a sustainable nuclear power

Nuclear power to be sustainable requires the fulfilling of peculiar constraints, which include addressing the proliferation risk. One possible route for sustainability is that to adopt a fuel cycle based on thorium. However, comparison with uranium cycle indicates that thorium cycle utilization is premature. Instead, a promising short-term option is the use of inert matrix fuels, possibly containing thoria, in a once-through cycle. Irradiation tests performed in the Halden reactor show encouraging behaviour under irradiation. Furthermore, these fuels are very well suited for a direct disposal in a geological repository.