Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facility

[EN] After the injection of borated water during accidental sequences, the intrusion of nitrogen gas from the accumulators once emptied can degrade heat transfer mechanisms and thus hinder core cooling. The non-condensable gas that enters the cold legs transfers and accumulates in the U-tubes of the...

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Autores: Ten-Gallardo, Tomás, Gallardo Bermell, Sergio|||0000-0002-3703-9983, M. Lorduy|||0000-0002-8942-8278, Verdú Martín, Gumersindo Jesús|||0000-0001-5098-080X
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universitat Politècnica de València (UPV)
Repositorio:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Idioma:inglés
OAI Identifier:oai:riunet.upv.es:10251/226861
Acceso en línea:https://riunet.upv.es/handle/10251/226861
Access Level:acceso abierto
Palabra clave:Nitrogen intrusion
TRACE5
Large scale test facility
SBLOCA
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spelling Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facilityTen-Gallardo, TomásGallardo Bermell, Sergio|||0000-0002-3703-9983M. Lorduy|||0000-0002-8942-8278Verdú Martín, Gumersindo Jesús|||0000-0001-5098-080XNitrogen intrusionTRACE5Large scale test facilitySBLOCA[EN] After the injection of borated water during accidental sequences, the intrusion of nitrogen gas from the accumulators once emptied can degrade heat transfer mechanisms and thus hinder core cooling. The non-condensable gas that enters the cold legs transfers and accumulates in the U-tubes of the steam generators and their outlet plenums. This can cause flow stagnation and even prevent reflux cooling. Furthermore, a temporary and fluctuating increase in primary pressure may occur, disabling the low-pressure injection system pumps to restore the inventory. In this scenario, it is essential to confirm the effectiveness of the accident management measures under the influence of non-condensable gas. To date, several experimental studies have been conducted within the framework of OECD/NEA programs at experimental facilities such as LSTF, PKL, or ATLAS (all related to PWRtype designs) where the issue of non-condensable gas intrusion has been studied, but always as a secondary objective of the analyzed sequences. In this work, three SBLOCA in the reactor pressure vessel of the LSTF facility are analyzed to determine the effect of nitrogen intrusion in the primary system. For calculations, the thermalhydraulic code TRACE5 patch 5 is used. Results include the evolution of the main thermal-hydraulic parameters (pressures, mass flow rates and temperatures) and sensitivity cases for different scenarios of nitrogen intrusion. Based on the analysis of three experiments, it can be concluded that while nitrogen accumulation in the U-tubes is a common effect, the activation of safety systems such as LPIS depends on the location, size of the break and action management measures.This work has been developed under the project "Analisis del impacto de la intrusion de gas nitrogeno en el circuito primario de refrigeracion de plantas nucleares" (SUBV-6/2023, Subvenciones destinadas a la realizacion de proyectos de I + D + i relacionados con las funciones del CSN) . The authors are grateful to the Spanish Safety Council (CSN) that has financed this project.ElsevierDepartamento de Ingeniería Química y NuclearDepartamento de Estadística e Investigación Operativa Aplicadas y CalidadEscuela Técnica Superior de Ingeniería IndustrialInstituto Universitario de Seguridad Industrial, Radiofísica y MedioambientalConsejo de Seguridad NuclearRepositorio Institucional de la Universitat Politècnica de València Riunet20252025-11-01journal articlehttp://purl.org/coar/resource_type/c_6501VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/articleapplication/pdfhttps://riunet.upv.es/handle/10251/226861reponame:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valénciainstname:Universitat Politècnica de València (UPV)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2Reconocimiento - No comercial (by-nc) http://creativecommons.org/licenses/by-nc/4.0/info:eu-repo/semantics/openAccessoai:riunet.upv.es:10251/2268612026-06-13T07:49:27Z
dc.title.none.fl_str_mv Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facility
title Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facility
spellingShingle Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facility
Ten-Gallardo, Tomás
Nitrogen intrusion
TRACE5
Large scale test facility
SBLOCA
title_short Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facility
title_full Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facility
title_fullStr Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facility
title_full_unstemmed Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facility
title_sort Analysis of nitrogen intrusion from ECCS accumulators in SBLOCA scenarios at LSTF test facility
dc.creator.none.fl_str_mv Ten-Gallardo, Tomás
Gallardo Bermell, Sergio|||0000-0002-3703-9983
M. Lorduy|||0000-0002-8942-8278
Verdú Martín, Gumersindo Jesús|||0000-0001-5098-080X
author Ten-Gallardo, Tomás
author_facet Ten-Gallardo, Tomás
Gallardo Bermell, Sergio|||0000-0002-3703-9983
M. Lorduy|||0000-0002-8942-8278
Verdú Martín, Gumersindo Jesús|||0000-0001-5098-080X
author_role author
author2 Gallardo Bermell, Sergio|||0000-0002-3703-9983
M. Lorduy|||0000-0002-8942-8278
Verdú Martín, Gumersindo Jesús|||0000-0001-5098-080X
author2_role author
author
author
dc.contributor.none.fl_str_mv Departamento de Ingeniería Química y Nuclear
Departamento de Estadística e Investigación Operativa Aplicadas y Calidad
Escuela Técnica Superior de Ingeniería Industrial
Instituto Universitario de Seguridad Industrial, Radiofísica y Medioambiental
Consejo de Seguridad Nuclear
Repositorio Institucional de la Universitat Politècnica de València Riunet
dc.subject.none.fl_str_mv Nitrogen intrusion
TRACE5
Large scale test facility
SBLOCA
topic Nitrogen intrusion
TRACE5
Large scale test facility
SBLOCA
description [EN] After the injection of borated water during accidental sequences, the intrusion of nitrogen gas from the accumulators once emptied can degrade heat transfer mechanisms and thus hinder core cooling. The non-condensable gas that enters the cold legs transfers and accumulates in the U-tubes of the steam generators and their outlet plenums. This can cause flow stagnation and even prevent reflux cooling. Furthermore, a temporary and fluctuating increase in primary pressure may occur, disabling the low-pressure injection system pumps to restore the inventory. In this scenario, it is essential to confirm the effectiveness of the accident management measures under the influence of non-condensable gas. To date, several experimental studies have been conducted within the framework of OECD/NEA programs at experimental facilities such as LSTF, PKL, or ATLAS (all related to PWRtype designs) where the issue of non-condensable gas intrusion has been studied, but always as a secondary objective of the analyzed sequences. In this work, three SBLOCA in the reactor pressure vessel of the LSTF facility are analyzed to determine the effect of nitrogen intrusion in the primary system. For calculations, the thermalhydraulic code TRACE5 patch 5 is used. Results include the evolution of the main thermal-hydraulic parameters (pressures, mass flow rates and temperatures) and sensitivity cases for different scenarios of nitrogen intrusion. Based on the analysis of three experiments, it can be concluded that while nitrogen accumulation in the U-tubes is a common effect, the activation of safety systems such as LPIS depends on the location, size of the break and action management measures.
publishDate 2025
dc.date.none.fl_str_mv 2025
2025-11-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
VoR
http://purl.org/coar/version/c_970fb48d4fbd8a85
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://riunet.upv.es/handle/10251/226861
url https://riunet.upv.es/handle/10251/226861
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
Reconocimiento - No comercial (by-nc)
http://creativecommons.org/licenses/by-nc/4.0/
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
Reconocimiento - No comercial (by-nc)
http://creativecommons.org/licenses/by-nc/4.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
instname:Universitat Politècnica de València (UPV)
instname_str Universitat Politècnica de València (UPV)
reponame_str RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
collection RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
repository.name.fl_str_mv
repository.mail.fl_str_mv
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