Numerical and experimental characterization of a new reduced-height CALORRE differential calorimeter for CALOR-I Irradiation in MITR

This paper presents the preliminary characterization of a new reduced-height CALORRE differential calorimeter designed by Aix Marseille University and fabricated in order to be tested and qualified under irradiation in the MITR experimental reactor within the framework of the CALOR-I program. The paper begins by focusing on the preparation of the irradiation campaign, providing a concise description of the MITR core, the water loop facility, and the newly fabricated differential calorimeter. Then, this work summarizes neutronic calculations performed for the CALORRE differential calorimeter to provide data for the irradiation campaign. MCNP calculation code was used to predict the neutron and gamma flux spectra, and total nuclear heating rate to the components of the calorimeter in a variety of positions. The MCNP model parameters and methodology are detailed and results are used to perform 3-D thermal modelling. Estimation of the response of the calorimeter calculated under real conditions considering local heat sources determined by the NRL of the MIT using MCNP code is given. Next, the paper presents the experimental characterization conducted under laboratory conditions. This section includes a detailed presentation of the updated experimental set-up and the key metrological characteristics of the sensor response obtained from the experimental results. In conclusion, the paper offers some final remarks and prospects to realize the irradiation campaign successfully.