Options for plutonium management: MOX, ThO2-based fuels and inert matrices

A surplus exists of Pu due to reprocessing of spent fuel (civilian Pu, C-Pu) and due to the planned dismantling of nuclear warheads (W-Pu). The decision of how to use this Pu to produce energy, while simultaneously achieving a satisfactory disposition rate and a high proliferation resistance, is a matter of both politics and materials science and technology. The presentation is restricted to the latter aspect. In particular, three options are discussed: going MOX with ''conventional'' UO2-based fuels, using ThO2 as a matrix and incorporation of Pu in an inert matrix with low atomic numbers such as spinel MgAl2O4. The criteria for selecting suitable inert matrices are discussed and results of materials property measurements are given. (author)