Preliminary neutronic analysis of minimum critical and sub-critical cores (ERANOS deterministic code)

This work was carried out in the framework of the EU FP7 project MAXSIMA “Methodology, Analysis and eXperiments for the "Safety In MYRRHA Assessment”. The MYRRHA reactor, planned to be built by 2023 at the SCK-CEN research center in Mol (Belgium), was identified as a long term supporting research facility for all ESNII systems and as such put in the high-priority list of ESFRI. The MAXSIMA WP2 deals with the safety analyses to support the licensing of MYRRHA, in which Task 2.1 is devoted to the neutronic and shielding analyses in support of safety studies. The neutronic parameters (for TH safety studies) have to be evaluated through the analysis of envelope cases - minimum and maximum cores in both critical and sub-critical operational modes - that yield the possible working range of the MYRRHA core. The report summarizes the presentation done by the author in the SEARCH-MAXSIMA meeting on May 7-8th, 2013, at the CRS4 research centre in Pula (Italy). He showed the neutronic model of the MYRRHA-MAXSIMA core and the major design changes from the MYRRHA-FASTEF core defined in the previous EU FP7 CDT project. Based on such design evolution, he defined the minimum critical and sub-critical cores (with fresh fuel and no In-Pile Sections for samples irradiation) and reported their preliminary neutronic analyses by means of the ERANOS 2.2 deterministic code.