Comparison of the Responses of New Reduced-Size Calorimetric Cells Made of Different Structure Materials for High Energy Deposition

Abstract

This paper concerns experimental and numerical works on a new differential calorimeter called CALORRE and validated recently under irradiation conditions in MARIA reactor at low nuclear absorbed dose rate level. Works focus on a specific configuration of CALORRE which was designed especially for the measurement of high nuclear energy deposition rates inside Material Testing Reactors. Due to the high level, a new calibration system was fabricated in order to determine the response of the new configuration under laboratory conditions for a very wide range of electrical power never applied in the literature. The response of the new configuration can be considered linear for this very wide range of electrical power. An analytical calculation shows the contribution of each heat transfer in specific zones. 3D thermal simulations performed by means of COMSOL Multiphysics under irradiation conditions give the predictions of the calorimeter behavior under real conditions (up to 20W.g−1).

Review of CALORRE Calorimeter Characterizations Under Laboratory and Irradiation Conditions

“…Consequently, a reducedheight configuration is suited for higher values of nuclear heating rate compared to a full-height configuration. This reduction in sensitivity under real conditions was confirmed by a validated predicted model based on a heat balance [19][20]. For example, the configuration N°1, had a sensitivity of 88.9 °C.g.W -1 as against 49.6 °C.g.W -1 for the In addition, the aluminum configurations are suited to highest nuclear absorbed dose rate measurement [19][20] due to the low sensitivities.…”

“…More precisely, the full-height and half-surface aluminum configuration (configuration N°3) was qualified under laboratory conditions up to 60 W thanks to a new heating element system. This very large calibration range allowed the demonstration of the good running of the calorimetric cell for the maximal value of the nuclear absorbed dose rate inside the future JHR (20 W.g -1 ) [19][20].…”

“…The temperature of the coolant fluid flow as well as its velocity can be changed inside the in-core water-loop. By considering the constraints of the experimental set-up used for the calibration under laboratory conditions [16][17][18][19][20] and located at AMU, the in-core water-loop fluid flow temperature will be fixed around 50 °C but the required speed of the fluid flow through the induced heat transfer coefficient will be studied to ensure energy evacuation.…”

“…Regarding the previous irradiation campaign results, recent work [16][17][18][19][20], the results obtained for 6 other calorimetric cells and the expected nuclear absorbed dose rate inside the MITR, a very compact differential calorimeter with new reduced-height cells and a new assembly were defined and studied thanks to 3-D numerical thermal simulations with a COMSOL Multiphysics finite element code coupled with a heat transfer module. The aims were to remove the thermal contact resistances by means of a simplification of each cell head and their assembly and to reduce the total height of the calorimeter.…”

Calibration of a Single-Cell Calorimeter in a New Transient-state Test Bench

“…This calorimeter was designed and developed by the Polish National Center of Nuclear Research (NCBJ) to carry out experiments in the MARIA Reactor in 2014 and 2015. The aim of these two irradiation campaigns was the comparison of different calorimeters: KAROLINA calorimeter and gamma thermometer then KAROLINA calorimeter and two French differential calorimeters (CARMEN [5] and CALORRE [12,13]).…”