Fundamental properties and characteristics of flux distribution tallies using proper orthogonal decomposition

The flux distribution tallies using the proper orthogonal decomposition (POD) called “the POD tallies” have been developed in our previous study. The POD tallies can achieve dimensionality and statistical uncertainty reduction for a finely discretized flux distribution. Some characteristics of the P...

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Main Authors: Kondo Ryoichi, Yamamoto Akio, Endo Tomohiro
Format: Article
Language:English
Published: EDP Sciences 2025-01-01
Series:EPJ Nuclear Sciences & Technologies
Online Access:https://www.epj-n.org/articles/epjn/full_html/2025/01/epjn20250012/epjn20250012.html
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author Kondo Ryoichi
Yamamoto Akio
Endo Tomohiro
author_facet Kondo Ryoichi
Yamamoto Akio
Endo Tomohiro
author_sort Kondo Ryoichi
collection DOAJ
description The flux distribution tallies using the proper orthogonal decomposition (POD) called “the POD tallies” have been developed in our previous study. The POD tallies can achieve dimensionality and statistical uncertainty reduction for a finely discretized flux distribution. Some characteristics of the POD tallies, which are left by our previous work, are revealed in the present study. Firstly, the POD tallies with the track length estimator are newly implemented. Since the statistical uncertainty of the POD tallies is reduced compared with the cell tallies, the POD tallies with the track length estimator can obtain the most precise result among the present implantations. Secondly, the basis vectors obtained by the deterministic and the stochastic methods are compared. The statistical uncertainty of the snapshot data invokes the degradation of the extracted basis vectors. This result indicates that the deterministic method might be more efficient for the snapshot calculation. Finally, the impact of the covariances of expansion coefficients on the statistical uncertainty of expanded flux distribution is investigated. The reconstructed statistical uncertainty considering only the variances of the expansion coefficients differs from the reference. This result reveals that the covariances of the expansion coefficients are important to estimate the statistical uncertainty of the local flux in the flux distribution.
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spelling doaj-art-2b433e115dce4625bb4c6bb7c11afa6c2025-08-20T02:05:52ZengEDP SciencesEPJ Nuclear Sciences & Technologies2491-92922025-01-01112110.1051/epjn/2025019epjn20250012Fundamental properties and characteristics of flux distribution tallies using proper orthogonal decompositionKondo Ryoichi0https://orcid.org/0000-0001-8901-0157Yamamoto Akio1https://orcid.org/0000-0002-2896-3488Endo Tomohiro2https://orcid.org/0000-0002-6644-4398Nuclear Science and Engineering Center, Japan Atomic Energy AgencyDepartment of Applied Energy, Graduate School of Engineering, Nagoya UniversityDepartment of Applied Energy, Graduate School of Engineering, Nagoya UniversityThe flux distribution tallies using the proper orthogonal decomposition (POD) called “the POD tallies” have been developed in our previous study. The POD tallies can achieve dimensionality and statistical uncertainty reduction for a finely discretized flux distribution. Some characteristics of the POD tallies, which are left by our previous work, are revealed in the present study. Firstly, the POD tallies with the track length estimator are newly implemented. Since the statistical uncertainty of the POD tallies is reduced compared with the cell tallies, the POD tallies with the track length estimator can obtain the most precise result among the present implantations. Secondly, the basis vectors obtained by the deterministic and the stochastic methods are compared. The statistical uncertainty of the snapshot data invokes the degradation of the extracted basis vectors. This result indicates that the deterministic method might be more efficient for the snapshot calculation. Finally, the impact of the covariances of expansion coefficients on the statistical uncertainty of expanded flux distribution is investigated. The reconstructed statistical uncertainty considering only the variances of the expansion coefficients differs from the reference. This result reveals that the covariances of the expansion coefficients are important to estimate the statistical uncertainty of the local flux in the flux distribution.https://www.epj-n.org/articles/epjn/full_html/2025/01/epjn20250012/epjn20250012.html
spellingShingle Kondo Ryoichi
Yamamoto Akio
Endo Tomohiro
Fundamental properties and characteristics of flux distribution tallies using proper orthogonal decomposition
EPJ Nuclear Sciences & Technologies
title Fundamental properties and characteristics of flux distribution tallies using proper orthogonal decomposition
title_full Fundamental properties and characteristics of flux distribution tallies using proper orthogonal decomposition
title_fullStr Fundamental properties and characteristics of flux distribution tallies using proper orthogonal decomposition
title_full_unstemmed Fundamental properties and characteristics of flux distribution tallies using proper orthogonal decomposition
title_short Fundamental properties and characteristics of flux distribution tallies using proper orthogonal decomposition
title_sort fundamental properties and characteristics of flux distribution tallies using proper orthogonal decomposition
url https://www.epj-n.org/articles/epjn/full_html/2025/01/epjn20250012/epjn20250012.html
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AT yamamotoakio fundamentalpropertiesandcharacteristicsoffluxdistributiontalliesusingproperorthogonaldecomposition
AT endotomohiro fundamentalpropertiesandcharacteristicsoffluxdistributiontalliesusingproperorthogonaldecomposition