A multivariate representation of compressed pin-by-pin cross sections

Since the 80’s, industrial core calculations employ the two-step scheme based on prior cross sections preparation with few energy groups and in homogenized reference geometries. Spatial homogenization in the fuel assembly quarters is the most frequent calculation option nowadays, relying on efficien...

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Main Author: Tomatis Daniele
Format: Article
Language:English
Published: EDP Sciences 2021-01-01
Series:EPJ Nuclear Sciences & Technologies
Online Access:https://www.epj-n.org/articles/epjn/full_html/2021/01/epjn200019/epjn200019.html
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author Tomatis Daniele
author_facet Tomatis Daniele
author_sort Tomatis Daniele
collection DOAJ
description Since the 80’s, industrial core calculations employ the two-step scheme based on prior cross sections preparation with few energy groups and in homogenized reference geometries. Spatial homogenization in the fuel assembly quarters is the most frequent calculation option nowadays, relying on efficient nodal solvers using a coarse mesh. Pin-wise reaction rates are then reconstructed by dehomogenization techniques. The future trend of core calculations is moving however toward pin-by-pin explicit representations, where few-group cross sections are homogenized in the single pins at many physical conditions and many nuclides are selected for the simplified depletion chains. The resulting data model requires a considerable memory occupation on disk-files and the time needed to evaluate all data exceeds the limits for practical feasibility of multi-physics reactor calculations. In this work, we study the compression of pin-by-pin homogenized cross sections by the Hotelling transform in typical PWR fuel assemblies. The reconstruction of these quantities at different physical states of the assembly is then addressed by interpolation of only a few compressed coefficients, instead of interpolating separately each homogenized cross section. Savings in memory higher than 90% are observed, which result in important gains in runtime when interpolating the few-group data.
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spelling doaj.art-9bbb288a00a44e55b5e72b15f2714ac72022-12-21T21:34:43ZengEDP SciencesEPJ Nuclear Sciences & Technologies2491-92922021-01-017810.1051/epjn/2021006epjn200019A multivariate representation of compressed pin-by-pin cross sectionsTomatis Danielehttps://orcid.org/0000-0001-7314-2227Since the 80’s, industrial core calculations employ the two-step scheme based on prior cross sections preparation with few energy groups and in homogenized reference geometries. Spatial homogenization in the fuel assembly quarters is the most frequent calculation option nowadays, relying on efficient nodal solvers using a coarse mesh. Pin-wise reaction rates are then reconstructed by dehomogenization techniques. The future trend of core calculations is moving however toward pin-by-pin explicit representations, where few-group cross sections are homogenized in the single pins at many physical conditions and many nuclides are selected for the simplified depletion chains. The resulting data model requires a considerable memory occupation on disk-files and the time needed to evaluate all data exceeds the limits for practical feasibility of multi-physics reactor calculations. In this work, we study the compression of pin-by-pin homogenized cross sections by the Hotelling transform in typical PWR fuel assemblies. The reconstruction of these quantities at different physical states of the assembly is then addressed by interpolation of only a few compressed coefficients, instead of interpolating separately each homogenized cross section. Savings in memory higher than 90% are observed, which result in important gains in runtime when interpolating the few-group data.https://www.epj-n.org/articles/epjn/full_html/2021/01/epjn200019/epjn200019.html
spellingShingle Tomatis Daniele
A multivariate representation of compressed pin-by-pin cross sections
EPJ Nuclear Sciences & Technologies
title A multivariate representation of compressed pin-by-pin cross sections
title_full A multivariate representation of compressed pin-by-pin cross sections
title_fullStr A multivariate representation of compressed pin-by-pin cross sections
title_full_unstemmed A multivariate representation of compressed pin-by-pin cross sections
title_short A multivariate representation of compressed pin-by-pin cross sections
title_sort multivariate representation of compressed pin by pin cross sections
url https://www.epj-n.org/articles/epjn/full_html/2021/01/epjn200019/epjn200019.html
work_keys_str_mv AT tomatisdaniele amultivariaterepresentationofcompressedpinbypincrosssections
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