{"id":{"repo_id":"uoit","oai_identifier":"oai:ontariotechu.scholaris.ca:10155/740"},"canonical_url":"https://search.dev.ndltd.org/etd/uoit/oai:ontariotechu.scholaris.ca:10155/740","repository":{"repo_id":"uoit","name":"Ontario Institute of Technology","base_url":"https://ontariotechu.scholaris.ca/server/oai/request"},"display":{"title":"Investigation of sub-cell homogenization for PHWR lattice cells using superhomogenization factors","abstract":"To avoid the computational effort associated with full-core neutron transport calculations, full-core neutronics calculations for Pressurized Heavy-Water Reactors (PHWRs) are usually performed in diffusion theory using an approximate core model, whereby only two energy groups are utilized and two-group neutronic properties (i.e. macroscopic cross sections and diffusion coefficients) are homogenized in two dimensions over large sub-domains, each corresponding to a 28.6 cm x 28.6 cm lattice cell. The lattice cell is the elementary geometrical unit describing the rectangular array of fuel channels comprising the PHWR core. The use of lattice-cell homogenization introduces some computational errors. One possible way to reduce such homogenization errors is to sub-divide the lattice cell into sub-cells and perform sub-cell-level homogenization. In this study, the PHWR lattice cell is divided into 3 x 3 sub-cells. Full-cell-averaged, as well as sub-cell-averaged two-group cross-sections, are generated for subsequent use in an equivalent two group two-dimensional diffusion model. Cross sections with Superhomogenization (SPH) [Hebert, 2009] factors are also utilised in an attempt to improve accuracy. The effect of using different homogenization models (full cell, partial cell, partial-cell with SPH-corrected cross sections) is tested on a two-dimensional partial-core model consisting of 3 x 3 lattice cells (bundles). Results from reference transport model with detailed geometry 69-group are compared with cell-homogenized two-group diffusion results obtained using full-cell homogenization and sub-cell homogenization with and without SPH correction factors. The application of sub-cell homogenization, as well as the use of SPH correction factors, is found to have only a minimal effect on computational accuracy.","abstract_html":"To avoid the computational effort associated with full-core neutron transport calculations, full-core neutronics calculations for Pressurized Heavy-Water Reactors (PHWRs) are usually performed in diffusion theory using an approximate core model, whereby only two energy groups are utilized and two-group neutronic properties (i.e. macroscopic cross sections and diffusion coefficients) are homogenized in two dimensions over large sub-domains, each corresponding to a 28.6 cm x 28.6 cm lattice cell. The lattice cell is the elementary geometrical unit describing the rectangular array of fuel channels comprising the PHWR core. The use of lattice-cell homogenization introduces some computational errors. One possible way to reduce such homogenization errors is to sub-divide the lattice cell into sub-cells and perform sub-cell-level homogenization. In this study, the PHWR lattice cell is divided into 3 x 3 sub-cells. Full-cell-averaged, as well as sub-cell-averaged two-group cross-sections, are generated for subsequent use in an equivalent two group two-dimensional diffusion model. Cross sections with Superhomogenization (SPH) [Hebert, 2009] factors are also utilised in an attempt to improve accuracy. The effect of using different homogenization models (full cell, partial cell, partial-cell with SPH-corrected cross sections) is tested on a two-dimensional partial-core model consisting of 3 x 3 lattice cells (bundles). Results from reference transport model with detailed geometry 69-group are compared with cell-homogenized two-group diffusion results obtained using full-cell homogenization and sub-cell homogenization with and without SPH correction factors. The application of sub-cell homogenization, as well as the use of SPH correction factors, is found to have only a minimal effect on computational accuracy.","abstract_has_math":false,"creators":["Mohapatra, Subhramanyu"],"institution":"University of Ontario Institute of Technology","degree_name":"Master of Applied Science (MASc)","degree_level":null,"degree_discipline":"Nuclear Engineering","degree_department":null,"school":null,"contributors":[],"advisors":["Nichita, Eleodor"],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-12-01","date_published":"2016-12-01","updated_at":"2026-07-24T05:35:20Z","subjects":["Applied reactor physics","Superhomogenization","PHWR","SPH factors"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10155/740","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Nichita, Eleodor"]},{"key":"dc:creator","label":"Author","values":["Mohapatra, Subhramanyu"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2017-04-20T20:29:50Z","2022-03-25T18:49:28Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2017-04-20T20:29:50Z","2022-03-25T18:49:28Z"]},{"key":"dc:date.issued","label":"Date","values":["2016-12-01"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Nuclear Engineering"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Applied Science (MASc)"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Ontario Institute of Technology"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Applied reactor physics","Superhomogenization","PHWR","SPH factors"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10155/740"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["To avoid the computational effort associated with full-core neutron transport calculations, full-core neutronics calculations for Pressurized Heavy-Water Reactors (PHWRs) are usually performed in diffusion theory using an approximate core model, whereby only two energy groups are utilized and two-group neutronic properties (i.e. macroscopic cross sections and diffusion coefficients) are homogenized in two dimensions over large sub-domains, each corresponding to a 28.6 cm x 28.6 cm lattice cell. The lattice cell is the elementary geometrical unit describing the rectangular array of fuel channels comprising the PHWR core. The use of lattice-cell homogenization introduces some computational errors. One possible way to reduce such homogenization errors is to sub-divide the lattice cell into sub-cells and perform sub-cell-level homogenization. In this study, the PHWR lattice cell is divided into 3 x 3 sub-cells. Full-cell-averaged, as well as sub-cell-averaged two-group cross-sections, are generated for subsequent use in an equivalent two group two-dimensional diffusion model. Cross sections with Superhomogenization (SPH) [Hebert, 2009] factors are also utilised in an attempt to improve accuracy. The effect of using different homogenization models (full cell, partial cell, partial-cell with SPH-corrected cross sections) is tested on a two-dimensional partial-core model consisting of 3 x 3 lattice cells (bundles). Results from reference transport model with detailed geometry 69-group are compared with cell-homogenized two-group diffusion results obtained using full-cell homogenization and sub-cell homogenization with and without SPH correction factors. The application of sub-cell homogenization, as well as the use of SPH correction factors, is found to have only a minimal effect on computational accuracy."]},{"key":"dc:title","label":"Title","values":["Investigation of sub-cell homogenization for PHWR lattice cells using superhomogenization factors"]}]}],"canonical_facts":{"dc:contributor.advisor":["Nichita, Eleodor"],"dc:creator":["Mohapatra, Subhramanyu"],"dc:date.accessioned":["2017-04-20T20:29:50Z","2022-03-25T18:49:28Z"],"dc:date.available":["2017-04-20T20:29:50Z","2022-03-25T18:49:28Z"],"dc:date.issued":["2016-12-01"],"dc:description.abstract":["To avoid the computational effort associated with full-core neutron transport calculations, full-core neutronics calculations for Pressurized Heavy-Water Reactors (PHWRs) are usually performed in diffusion theory using an approximate core model, whereby only two energy groups are utilized and two-group neutronic properties (i.e. macroscopic cross sections and diffusion coefficients) are homogenized in two dimensions over large sub-domains, each corresponding to a 28.6 cm x 28.6 cm lattice cell. The lattice cell is the elementary geometrical unit describing the rectangular array of fuel channels comprising the PHWR core. The use of lattice-cell homogenization introduces some computational errors. One possible way to reduce such homogenization errors is to sub-divide the lattice cell into sub-cells and perform sub-cell-level homogenization. In this study, the PHWR lattice cell is divided into 3 x 3 sub-cells. Full-cell-averaged, as well as sub-cell-averaged two-group cross-sections, are generated for subsequent use in an equivalent two group two-dimensional diffusion model. Cross sections with Superhomogenization (SPH) [Hebert, 2009] factors are also utilised in an attempt to improve accuracy. The effect of using different homogenization models (full cell, partial cell, partial-cell with SPH-corrected cross sections) is tested on a two-dimensional partial-core model consisting of 3 x 3 lattice cells (bundles). Results from reference transport model with detailed geometry 69-group are compared with cell-homogenized two-group diffusion results obtained using full-cell homogenization and sub-cell homogenization with and without SPH correction factors. The application of sub-cell homogenization, as well as the use of SPH correction factors, is found to have only a minimal effect on computational accuracy."],"dc:identifier.uri":["https://hdl.handle.net/10155/740"],"dc:language.iso":["en"],"dc:subject":["Applied reactor physics","Superhomogenization","PHWR","SPH factors"],"dc:title":["Investigation of sub-cell homogenization for PHWR lattice cells using superhomogenization factors"],"dc:type":["Thesis"],"thesis:degree_discipline":["Nuclear Engineering"],"thesis:degree_name":["Master of Applied Science (MASc)"],"thesis:institution_name":["University of Ontario Institute of Technology"]},"updated_at":"2026-07-24T05:35:20Z"}