Application of ceramic nuclear fuel materials for innovative fuels and fuel cycles

Fuels for nuclear power reactors currently in operation for generating electricity are mostly the ceramic UO2 and the so-called mixed oxide (MOX) with uranium-plutonium oxide. The relevant technologies developed up to now are industrially matured, and still continue to be developed from the aspects of economy and safety, including high burn-up. Recently, fuel cycles with innovative fuels have been conceived and preliminary results from basic studies already exist with regard to the ever-increasing interest in the incineration of excess Pu materials from warheads and surplus reactor Pu stocks as well as minor actinide (MA) transmutation. These concepts employ mostly ceramic nuclear fuel materials such as ZrO2 and spinel-based oxides and non-oxides with ceramic matrices (nitrides and carbides). Problems that the relevant technologies face for fuels currently used in power reactors are first briefly treated in connection with their high burn-up behaviour. Issues concerning materials for the innovative fuels and fuel cycles mentioned above are subsequently discussed in a more detailed manner in view of their developmental status, material properties and irradiation behaviours studied up to the present time.