ELSY Neutronic Analysis: Status of the Open Square Design

This report has been carried out within the framework of the STREP ELSY (European Lead-cooled System, 6th EU FP) WP2, Task 2.2. It deals with the neutronic analysis of a 1500 MWth core, made of open square FAs and fuelled by MOX with reactor grade Pu (and depleted U). The starting point of this work is the Deliverable D6 (ENEA FPN-P9IX-004, 2008) in which a preliminary configuration of the core was defined. The latter also showed the capabilities of full self sustainability in Pu and of its own Minor Actinides burning (adiabatic approach). The present work represents the carrying on of 06 and was presented at WP2 Meeting on September 24th 2008 in Genoa. It confirms the viability of the adiabatic requirement and features some innovative solutions concerning the reactor absorbers (control, compensation and scram). In particular it is foreseen a sparse group of suitably arranged small B4C 'finger absorbers'. They can be inserted in the centre of each FA and permit to maintain an optimal power flattening during the fuel cycle.