Monte Carlo Simulation Study of a Differential Calorimeter Measuring the Nuclear Heating in Material Testing Reactors

Abstract

Abstract. The nuclear heating measurements in Material Testing Reactors (MTRs) are crucial for the study of nuclear materials and fuels under irradiation. The reference measurements of this nuclear heating are especially performed by a differential calorimeter including a graphite sample material. Then these measurements are used for other materials, other geometries, or other experimental conditions in order to predict the nuclear heating and thermal conditions induced in the irradiation devices. This paper will present new simulations with MCNP Monte-Carlo transport code to determine the gamma heating profile inside the calorimeter. The whole complex geometry of the sensor has been considered. We use as an input source in the model, the photon spectra calculated in various positions of CARMEN-1 irradiation program in OSIRIS reactor. After a description of the differential calorimeter device, the MCNP modeling used for the calculations of radial profile of nuclear heating inside the calorimeter elements will be introduced. The obtained results of different simulations will be detailed and discussed in this paper. The charged particle equilibrium inside the calorimeter elements will be studied. Then we will focus on parametric studies of the various components of the calorimeter. The influence of source type will be also took into account. Moreover the influence of the material used for the sample will be described.

Responses of Single-Cell and Differential Calorimeters: from Out-of-Pile Calibration to Irradiation Campaigns.

“…where  i is the density of the materials,   n E the nuclear energy deposition rate, and F i a specific factor [25] depending on the material in order to take into account the differences of ray-matter interactions according to the nature of the material.…”

“…The thermal numerical simulations are dedicated to carrying out parametric studies in order to improve knowledge of sensor behavior, to enhance and adapt the metrological characteristics of existing sensors, and to design new sensor configurations with new specific properties [23,24]. The modeling of interactions between nuclear radiation and matter is used to interpret experimental data (in particular to assess the contribution of neutrons and prompt and delayed photons to the nuclear energy deposition rate) or in addition to perform parametric studies [25]. This paper focuses on experimental and numerical thermal studies of two kinds of calorimeter (the differential calorimeter tested in the IN-CORE collaborative program and the single-cell calorimeter designed in the GAMMA-MAJOR program) from their out-of-pile calibration to their in-pile test to quantify nuclear heating.…”

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

“…In this context, the IN-CORE program [1][2][3], run jointly by the CEA and Aix-Marseille University since 2009, was created. Currently, two kinds of in-pile sensors are used to measure nuclear heating rate inside Material Testing Reactors (MTRs): the single-cell calorimeter [4,5], and the differential calorimeter [5][6][7][8][9][10]. Thus, for each kind of sensor, the IN-CORE program is involved in a scientific axis focusing on the enhancement of sensor design, their out-pile calibration means, methods (protocols) and their in-pile quantification methods, and interpretation analysis.…”

Impact Study on the Methodology used for Photon-Heating Determination in Material-Testing Reactors

“…For that reason, the calculation of another physical quantity, called KERMA (Kinetic Energy Released per MAss), is often preferred, as KERMA calculation with Monte Carlo codes only requires transport of neutral particles. However, KERMA is only an estimator of the absorbed dose and many conditions must be fulfilled for KERMA to be equal to absorbed dose, including the condition of charged-particle equilibrium [6] [7].…”