Ceramic matrixes for specific packaging

Since the end of the 1950s, solutions (mineral phases, glass) for the containment of final high-level, long-lived waste from nuclear fuel processing operations have been envisaged. Vitrification of this high-level waste gained international acceptance in the 1980s, and remains the benchmark solution for conditioning high-level waste today, thanks to the containment quality and performance of this type of matrix (see [BN 3 664]). The choice of this technology is based on :

• the capacity of the glass to incorporate elements from the fission product solution (around thirty elements);

• large-scale glass production by melting at reasonable temperatures (around 1,100°C);

• the absence of any significant impact on glass properties of irradiation damage caused by the decay of radionuclides incorporated in the glass lattice.

In France, research carried out under the Bataille law (law of December 30, 1991 on nuclear waste management) has made the confinement of certain long-lived radionuclides within specific ceramic matrices part of an advanced separation/conditioning scheme for long-lived radionuclides, as an alternative to the reference advanced separation/transmutation route.

Studies carried out within the NOMADE (new materials for waste) laboratory group, which includes CEA, CNRS, universities, EDF and Areva NC, have demonstrated the interest of several materials on the basis of a number of physico-chemical properties of interest . These properties include a high incorporation capacity, a densification capacity , good resistance to aqueous alteration, notably through dissolution phenomena