Inverse Problem Approach for the underwater localization of Fukushima Daiichi fuel debris with fission chambers

Autor: Q. Lecomte, R. Pissarello, Karim Boudergui, C. Thiam, R. Woo, M. Trocmé, Frederic Laine, H. Hamrita, Adrien Sari, R. Delalez, Camille Frangville, Jonathan Dumazert, Romain Coulon, Frederick Carrel, B. Krausz, M. Bakkali
Přispěvatelé: Laboratoire Capteurs et Architectures Electroniques (LCAE), Département Métrologie Instrumentation & Information (DM2I), Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire d'Intégration des Systèmes et des Technologies (LIST), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire National Henri Becquerel (LNHB), ONET Technologies, The authors thank Mitsubishi Research Institute, Inc. , for funding this research., Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département d'instrumentation Numérique (DIN (CEA-LIST)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Nuclear and High Energy Physics
nuclear power plant
Fission
Monte Carlo method
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
010403 inorganic & nuclear chemistry
7. Clean energy
01 natural sciences
030218 nuclear medicine & medical imaging
modelling
03 medical and health sciences
U235
0302 clinical medicine
neutron
sensor
Calibration
Neutron
[PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]
Underwater
signal processing
Monte Carlo
nuclear instrumentation
Physics
Neutron localization
instrumentation
irradiation
detector
Fuel debris
Detector
Mechanics
gamma-rays
Inverse problem
simulation
calibration
0104 chemical sciences
Maximum-Likelihood Expectation Maximization (ML-EM)
metrology
radioactivity
Fission chamber
Neutron source
ionizing radiation
Zdroj: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Elsevier, 2020, 954, pp.161347. ⟨10.1016/j.nima.2018.10.025⟩
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2020, 954, pp.161347. ⟨10.1016/j.nima.2018.10.025⟩
ISSN: 0168-9002
1872-9576
Popis: International audience; Fuel debris have a distinct neutron signature that can be detected to locate the said debris in a damaged nuclear power plant. Neutron measurement in a damaged PCV environment is however submitted to severe deployments constraints, including a high-dose-rate gamma background and limited available space. The study was therefore oriented towards small fission chambers (FC), with U-235-enriched active substrates. To investigate the expected performance of the FC in various irradiation conditions, a numerical model of the detector head was built. We describe the elaboration and experimental calibration of the numerical model and the Monte Carlo study of the fission rate inside U-235 coatings per generated neutron. The evaluation of a representative calibration coefficient then allowed us to carry out a multi-parameter performance study of a FC underwater, aiming at computing an explicit response function linking, on the one hand, the activity and spatial distribution of neutron emitters in a water container, with, one the other hand, the expected count rates measured by a fission chamber as a function of its radial and axial position inside the water volume. The FC underwater behavior was subsequently corroborated by a measurement campaign on a FC response, set at different positions inside a water drum, as a function of its axial and radial distance to a Cf-252 neutron source attached near the center of the container. We finally present an approach in which fuel debris localization is defined as an Inverse Problem, solvable with a Maximum-Likelihood Expectation Maximization (ML-EM) iterative algorithm. The projector matrix is built by capitalization on the results of the previously consolidated numerical studies. The ML-EM was tested on simulated data sets with a varying number of active voxels. Our first results indicate that, for a thermal neutron flux in the order of 10 n.cm−2.s−1 at the detector, originating voxels are identified with a spatial resolution in the radial plane in the order of 10 to 100 cm2.
Databáze: OpenAIRE
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