The ERANOS model (based on mechanical drawings) of the current frozen MYRRHA-FASTEF critical core

This work was carried out in the CDT/FASTEF EU FP7 praject: it deals with the preliminary core design of MYRRHA-FASTEF, a 100 MW LBE cooled reactor (working in both criticai and sub-critical modes) that should be able to demonstrate transmutation and associated technology. The report summarizes the presentation done at the WP2/T2.2 meeting (neutronic sub-task) at the SCK-CEN Headquarters in Brussels on January 18, 2011. It describes exhaustively the ERANOS neutranic model of the MYRRHA-FASTEF criticai core the model is very accurate since it is based on mechanical drawings. The main results of the ENEA deterministic analysis were compared with the ones coming fram a couple of Monte Carlo studies, done by SCK-CEN (MCNPX code) and by KIT (MCNP code). To facilate the comparison, and to better understand the reasons of discrepancies (if any), a four-step progressive approach to the current frozen criticai layout was adopted. The main outcome is the optimal agreement among the three codes at Beginning of Life.