Impact of the alternative fuel with plutonium and minor actinides on a CANDU reactor

The appropriate management of radioactive waste arising from the nuclear fuel cycle is considered to be a key issue in the development of sustainable nuclear energy systems. In this context, the partitioning and transmutation of actinides could play an important role due to very significant reductions in the actinide content and radiotoxicity of the high-level waste requiring geological disposal. The research of the transmutation of waste has been focused on three issues: long-lived fission products, plutonium, and minor actinides. For Pu and minor actinides transmutation CANDU reactor seems to be a well suitable versatile machine. In this paper it is presented the possibility to transmute Plutonium and minor actinides in a CANDU reactor. More specific, the paper presents the reactivity effects obtained by inserting a fuel containing Pu and minor actinides. Because the first stage in the transmutation process is the isotopes inventory formed in the spent fuel, in the paper an analysis of the resulting isotopes and their concentration before and after inserting the fuel element containing Pu and minor elements is made. All simulations are carried out by using WIMS - 5b code. The investigation is carried out in order to have a clear vision of the effects upon reactor reactivity and the isotope concentration in a CANDU reactor running with alternative fuel. As a conclusion, the analyses are made with the purpose of establishing an optimal transmutation solution from the point of view of nuclear safety and efficiency of the transmutation process in a CANDU reactor. (authors)