CALOR-I

The CALOR-I project, Compact-CALORimeter Irradiations inside the MIT research reactor, is cofunded by A*Midex, the NRL of the MIT and the CEA (2020-2022).

The project concerns the study of an innovative compact differential calorimeter recently patented by AMU and the CEA. It is dedicated to measuring the absorbed dose rate in Material Testing Reactors such as the Jules Horowitz Reactor under construction at the CEA in Cadarache in the south of France (start-up scheduled in 2025).

The CALOR-I project aims (a) to study, optimize and test a new French compact calorimeter, called CALORRE (CALOrimeter with Radial heat transfers for research Reactors) ) and patented by AMU and the CEA in 2015 (international extension realized), under real nuclear conditions inside the MITR, and (b) to map the nuclear heating rate inside its in-core loop using simultaneously CALORRE and a commercial single-cell calorimeter. CALORRE calorimeter has been tested in a previous irradiation campaign in the Polish MARIA reactor dedicated to comparing a commonly French differential calorimeter with a new Polish single-cell calorimeter (November 2015). Preliminary results of a non-compact CALORRE version were promising. The CALORRE calorimeter is a heat flow differential calorimeter (based on the nonadiabatic running principle). It is composed of two superposed identical calorimetric cells, one with and the other without a sample. The calorimetric cell containing no sample, called the reference cell, is needed in order to compensate the energy deposition on the structure of the sample calorimetric cell. Each cell is composed of three main parts instrumented by thermocouples: a cylindrical head, which serves as the sample holder in the case of the sample cell and contains a heating element (for calibration and specific measurement methods) in each cell; a horizontal fin located around the head to ensure radial heat transfers from the head towards the jacket; and a thin annular vertical fin which is in contact with the calorimeter jacket to evacuate energy towards the external cooling fluid flow. Thanks to this new design, the height of each cell is divided by a factor of up to 8 as compared with the commonly used French calorimetric cell with an axial heat exchange design.

The main objectives of the project are to:    

• define/validate a new CALORRE prototype for nuclear heating rates of up to 2 W/g
• establish for the first time an axial profile of the nuclear dose rate inside the MITR.

The project is composed of several work packages:

At present, 3D simulations are realized in order to define a new design of the CALORRE calorimetric cell and the differential calorimeter assembly. The results will be presented at ANIMMA 2021 (A. Volte, M. Carette, A. Lyoussi, G. Kohse, C. Reynard-Carette, Study review of the CALORRE differential calorimeter: definition of designs for different nuclear environments).