Fuel R+D in the context of CAPRA and SPIN

After a short introduction giving a general view of the fuel element designs considered for CAPRI (consumption of Pu) and SPIN (Incineration of minor actinides), this paper will be focused on the R+D devoted to fabrication aspects and basic (physical, thermochemical and mechanical) properties of these fuels. Available results and future program covering this objective will be described. On the one hand, fuel element designs are based on 'classical' UPuO2 fuel elements. These designs include high Pu content (up to 45%) for CAPRA and/or additions of small quantities of minor actinides as Neptunium for SPIN. Fabrication of such fuel pins, dedicated to the experimental irradiation programme in support, does not reveal any major problem. In addition to the demonstration of high burn-up behaviour of such pins, future R+D program is focused on optimisation of fuel fabrication (Pu homogeneity for example) and characterization measurements. On the other hand, 'advanced' fuel designs (Pu without U for CAPRA or minor actinides targets as Americium without Pu and U for SPIN) have been considered. For such elements, many design options, potentially interesting, exist and have to be tested; so, very extensive R+D programs are necessary to investigate, in a first stage, fabrication and basic properties. First results and future program concerning Pu and Am new compounds (as nitride), inert matrices and modification of pin design will be commented. In conclusion, the need of an international cooperation to perform such large programs will be underlined. (author) 6 figs., 14 refs