MULTISCALE THERMAL HYDRAULIC COUPLING METHODS FOR BOILING WATER REACTOR SIMULATION

Aaron Graham; Benjamin Collins; Bob Salko; Mehdi Asgari

doi:10.13182/PHYSOR22-37824

MULTISCALE THERMAL HYDRAULIC COUPLING METHODS FOR BOILING WATER REACTOR SIMULATION

Aaron Graham, Benjamin Collins, Bob Salko, Mehdi Asgari

Power Reactor Modeling

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

3 Scopus citations

Abstract

During the last two years, the Virtual Environment for Reactor Applications (VERA) has been extended to simulate boiling water reactors (BWRs). The thermal hydraulic effects present in BWRs are far more complex than those in pressurized water reactors (PWRs). Therefore, the runtime is significantly increase and convergence behavior worse compared to PWRs. Most of the additional runtime is spent during the first few coupled iterations, when the power shape is still rapidly evolving, dramatically affecting the thermal hydraulics (TH). To alleviate the increased computational expense, a multiscale TH coupling approach was developed in VERA in which a highly efficient, simplified TH model is solved for several coupled iterations until the power shape is partially converged. The simplified solution is used to inform the assembly-wise flow distribution in the high-fidelity TH solver CTF, reducing the amount of work required to properly balance the pressure drop in each channel and reducing runtime for the couple calculation. Because the final TH calculations are performed with CTF, there is ultimately no impact on the accuracy of the converged solution. This paper presents the details of this multiscale TH coupling approach, along with results for a 4×4 array of GE-14 fuel bundles and whole-core coupled simulations of the Hatch core. These two cases show that the multiscale approach dramatically reduces the runtime of coupled BWR simulations.

Original language	English
Title of host publication	Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022
Publisher	American Nuclear Society
Pages	2296-2305
Number of pages	10
ISBN (Electronic)	9780894487873
DOIs	https://doi.org/10.13182/PHYSOR22-37824
State	Published - 2022
Event	2022 International Conference on Physics of Reactors, PHYSOR 2022 - Pittsburgh, United States Duration: May 15 2022 → May 20 2022

Publication series

Name	Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022

Conference

Conference	2022 International Conference on Physics of Reactors, PHYSOR 2022
Country/Territory	United States
City	Pittsburgh
Period	05/15/22 → 05/20/22

Funding

∗ Notice: This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). The authors wish to thank Exelon for initiating the VERA BWR project and providing the data necessary to build and validate the BWR models. The authors also wish to acknowledge that this project was funded through the US Department of Energy (DOE) Office of Nuclear Energy (NE).

Keywords

BWRs
VERA
multiphysics
multiscale
thermal hydraulics

Access to Document

10.13182/PHYSOR22-37824

Cite this

Graham, A., Collins, B., Salko, B., & Asgari, M. (2022). MULTISCALE THERMAL HYDRAULIC COUPLING METHODS FOR BOILING WATER REACTOR SIMULATION. In Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022 (pp. 2296-2305). (Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022). American Nuclear Society. https://doi.org/10.13182/PHYSOR22-37824

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abstract = "During the last two years, the Virtual Environment for Reactor Applications (VERA) has been extended to simulate boiling water reactors (BWRs). The thermal hydraulic effects present in BWRs are far more complex than those in pressurized water reactors (PWRs). Therefore, the runtime is significantly increase and convergence behavior worse compared to PWRs. Most of the additional runtime is spent during the first few coupled iterations, when the power shape is still rapidly evolving, dramatically affecting the thermal hydraulics (TH). To alleviate the increased computational expense, a multiscale TH coupling approach was developed in VERA in which a highly efficient, simplified TH model is solved for several coupled iterations until the power shape is partially converged. The simplified solution is used to inform the assembly-wise flow distribution in the high-fidelity TH solver CTF, reducing the amount of work required to properly balance the pressure drop in each channel and reducing runtime for the couple calculation. Because the final TH calculations are performed with CTF, there is ultimately no impact on the accuracy of the converged solution. This paper presents the details of this multiscale TH coupling approach, along with results for a 4×4 array of GE-14 fuel bundles and whole-core coupled simulations of the Hatch core. These two cases show that the multiscale approach dramatically reduces the runtime of coupled BWR simulations.",

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author = "Aaron Graham and Benjamin Collins and Bob Salko and Mehdi Asgari",

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language = "English",

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Graham, A, Collins, B, Salko, B & Asgari, M 2022, MULTISCALE THERMAL HYDRAULIC COUPLING METHODS FOR BOILING WATER REACTOR SIMULATION. in Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022. Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022, American Nuclear Society, pp. 2296-2305, 2022 International Conference on Physics of Reactors, PHYSOR 2022, Pittsburgh, United States, 05/15/22. https://doi.org/10.13182/PHYSOR22-37824

MULTISCALE THERMAL HYDRAULIC COUPLING METHODS FOR BOILING WATER REACTOR SIMULATION. / Graham, Aaron; Collins, Benjamin; Salko, Bob et al.
Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022. American Nuclear Society, 2022. p. 2296-2305 (Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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AU - Collins, Benjamin

AU - Salko, Bob

AU - Asgari, Mehdi

PY - 2022

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N2 - During the last two years, the Virtual Environment for Reactor Applications (VERA) has been extended to simulate boiling water reactors (BWRs). The thermal hydraulic effects present in BWRs are far more complex than those in pressurized water reactors (PWRs). Therefore, the runtime is significantly increase and convergence behavior worse compared to PWRs. Most of the additional runtime is spent during the first few coupled iterations, when the power shape is still rapidly evolving, dramatically affecting the thermal hydraulics (TH). To alleviate the increased computational expense, a multiscale TH coupling approach was developed in VERA in which a highly efficient, simplified TH model is solved for several coupled iterations until the power shape is partially converged. The simplified solution is used to inform the assembly-wise flow distribution in the high-fidelity TH solver CTF, reducing the amount of work required to properly balance the pressure drop in each channel and reducing runtime for the couple calculation. Because the final TH calculations are performed with CTF, there is ultimately no impact on the accuracy of the converged solution. This paper presents the details of this multiscale TH coupling approach, along with results for a 4×4 array of GE-14 fuel bundles and whole-core coupled simulations of the Hatch core. These two cases show that the multiscale approach dramatically reduces the runtime of coupled BWR simulations.

AB - During the last two years, the Virtual Environment for Reactor Applications (VERA) has been extended to simulate boiling water reactors (BWRs). The thermal hydraulic effects present in BWRs are far more complex than those in pressurized water reactors (PWRs). Therefore, the runtime is significantly increase and convergence behavior worse compared to PWRs. Most of the additional runtime is spent during the first few coupled iterations, when the power shape is still rapidly evolving, dramatically affecting the thermal hydraulics (TH). To alleviate the increased computational expense, a multiscale TH coupling approach was developed in VERA in which a highly efficient, simplified TH model is solved for several coupled iterations until the power shape is partially converged. The simplified solution is used to inform the assembly-wise flow distribution in the high-fidelity TH solver CTF, reducing the amount of work required to properly balance the pressure drop in each channel and reducing runtime for the couple calculation. Because the final TH calculations are performed with CTF, there is ultimately no impact on the accuracy of the converged solution. This paper presents the details of this multiscale TH coupling approach, along with results for a 4×4 array of GE-14 fuel bundles and whole-core coupled simulations of the Hatch core. These two cases show that the multiscale approach dramatically reduces the runtime of coupled BWR simulations.

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M3 - Conference contribution

AN - SCOPUS:85184961180

T3 - Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022

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BT - Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022

PB - American Nuclear Society

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Y2 - 15 May 2022 through 20 May 2022

ER -

MULTISCALE THERMAL HYDRAULIC COUPLING METHODS FOR BOILING WATER REACTOR SIMULATION

Abstract

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Keywords

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