Nuclear reactor core modelling in multifunctional simulators: Dissertation

Research output: ThesisDissertationCollection of Articles

2 Citations (Scopus)

Abstract

This thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR -type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and VVER-type APROS core models have been studied to assess the possibilities for using three-dimensional cores in training simulators. The core model results have been compared with the Loviisa VVER-type plant measurement data in steady state and in some transients. Hypothetical control rod withdrawal, ejection and boron dilution transients have been calculated with various three-dimensional core models for the Loviisa VVER-440 core. Several ATWS analyses for the VVER-1000/91 plant have been performed using the three-dimensional core model. In this context, the results of APROS have been compared in detail with the results of the HEXTRAN code. The three-dimensional Olkiluoto BWR-type core model has been used for transient calculation and for severe accident re-criticality studies. The one-dimensional core model is at present used in several plant analyser and training simulator applications and it has been used extensively for safety analyses in the Loviisa VVER-440 plant modernisation project.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Salomaa, Rainer, Supervisor, External person
Award date12 Mar 1999
Place of PublicationEspoo
Publisher
Print ISBNs951-38-5361-6
Electronic ISBNs951-38-5364-0
Publication statusPublished - 1999
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

Reactor cores
Simulators
Hydraulic models
Channel flow
Core analysis
Control rods

Keywords

  • nuclear reactors
  • reactor cores
  • simulation
  • plant analyser
  • training simulator
  • safety analysis
  • APROS

Cite this

Puska, E-K. (1999). Nuclear reactor core modelling in multifunctional simulators: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Puska, Eija-Karita. / Nuclear reactor core modelling in multifunctional simulators : Dissertation. Espoo : VTT Technical Research Centre of Finland, 1999. 67 p.
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Nuclear reactor core modelling in multifunctional simulators : Dissertation. / Puska, Eija-Karita.

Espoo : VTT Technical Research Centre of Finland, 1999. 67 p.

Research output: ThesisDissertationCollection of Articles

TY - THES

T1 - Nuclear reactor core modelling in multifunctional simulators

T2 - Dissertation

AU - Puska, Eija-Karita

N1 - Project code: N9SU00029

PY - 1999

Y1 - 1999

N2 - This thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR -type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and VVER-type APROS core models have been studied to assess the possibilities for using three-dimensional cores in training simulators. The core model results have been compared with the Loviisa VVER-type plant measurement data in steady state and in some transients. Hypothetical control rod withdrawal, ejection and boron dilution transients have been calculated with various three-dimensional core models for the Loviisa VVER-440 core. Several ATWS analyses for the VVER-1000/91 plant have been performed using the three-dimensional core model. In this context, the results of APROS have been compared in detail with the results of the HEXTRAN code. The three-dimensional Olkiluoto BWR-type core model has been used for transient calculation and for severe accident re-criticality studies. The one-dimensional core model is at present used in several plant analyser and training simulator applications and it has been used extensively for safety analyses in the Loviisa VVER-440 plant modernisation project.

AB - This thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR -type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and VVER-type APROS core models have been studied to assess the possibilities for using three-dimensional cores in training simulators. The core model results have been compared with the Loviisa VVER-type plant measurement data in steady state and in some transients. Hypothetical control rod withdrawal, ejection and boron dilution transients have been calculated with various three-dimensional core models for the Loviisa VVER-440 core. Several ATWS analyses for the VVER-1000/91 plant have been performed using the three-dimensional core model. In this context, the results of APROS have been compared in detail with the results of the HEXTRAN code. The three-dimensional Olkiluoto BWR-type core model has been used for transient calculation and for severe accident re-criticality studies. The one-dimensional core model is at present used in several plant analyser and training simulator applications and it has been used extensively for safety analyses in the Loviisa VVER-440 plant modernisation project.

KW - nuclear reactors

KW - reactor cores

KW - simulation

KW - plant analyser

KW - training simulator

KW - safety analysis

KW - APROS

M3 - Dissertation

SN - 951-38-5361-6

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Puska E-K. Nuclear reactor core modelling in multifunctional simulators: Dissertation. Espoo: VTT Technical Research Centre of Finland, 1999. 67 p.