Preliminary neutronic analyses of the MYRTHE-CC11 core results with the ERANOS code

This work was carried out in the framework of the EU H2020 project MYRTHE “MYRRHA Research and Transmutation Endeavour”. The MYRTHE Work Package 5 (WP5) deals with the experiments in support of the MYRRHA design evolution, where MYRRHA is the lead-bismuth cooled multi-purpose irradiation facility planned to be built at the SCK•CEN research centre in Mol, Belgium. In MYRTHE WP5, a series of critical and sub-critical experiments were performed in the VENUS-F zero power reactor (located at SCK•CEN) and simulated by the project partners with different neutronic codes. This document summarizes the presentation done by the author in the second MYRTHE WP5 technical meeting on October 26th, 2017, at the SCK•CEN Head Quarters in Brussels. It reports the main results of a detailed neutronic study carried out with the ERANOS ver. 2.2 deterministic code coupled with the JEFF3.1 and ENDF/B-VI.8 nuclear data libraries. The critical core layout analysed – called CC11 core - was assembled in VENUS-F and characterized during May - June 2017. In the ERANOS analysis, the experimental conditions were precisely reproduced and a quite significant accuracy was obtained in the simulations. The main physical quantities investigated were: the core criticality, the delayed neutron parameters, the control rods worth, some reactivity effects (e.g., bismuth void worth) and the F28/F25 spectral index (i.e., the ratio between the fission rates of U238 and U235).