The GFR in the frame of advanced fuel cycles: the use of DA as an improved way to minimize the MA content in the SNF

Among the strategies which carry on the main aim of minimizing MA (Minor Actinides) inventories, transmutation is one of the most. In fact, FR (Fast Reactors), in addition to energy generation, can also decrease nuclear waste radiotoxicity mainly by transmutation processes. The implementation of this strategy might be helped by some typical features of FR, as high neutron fluxes and high neutron capture cross-sections. Particularly GFR (Gas-cooled Fast Reactor) charged with some moderated DA (Dedicated Assemblies) could supply such requirements for transmutation process. Previously filled with MA, those DA are inserted in the active core pointing to the optimization and improvement in the reactor burning capability. Different configurations have been analysed to maximise reduction in MA amounts but with the constraint to maintain acceptable (from safety point of view) the β values. Two figures of merit have been adopted to evaluate the best solution: The ratio between the masses at EoC (End of Cycle) and at BoC (Beginning of Cycle) limited to the materials contained in DA and the same ratio considering the MA present in the whole core. Finally a “disposal” alternative option (with a longer storage time assumed before reprocessing MA) has been considered, too. Such preliminary optimization and the analysis of the obtained results are the main topics of the work.