A1 Journal article (refereed), original research

Pool stratification and mixing induced by steam injection through spargers: CFD modelling of the PPOOLEX and PANDA experiments


Publication Details
Authors: Gallego-Marcos Ignacio, Kudinov Pavel, Villanueva Walter, Kapulla Ralf, Paranjape Sidharth, Paladino Domenico, Laine Jani, Puustinen Markku, Räsänen Antti, Pyy Lauri, Kotro Eetu
Publisher: Elsevier
Publication year: 2019
Language: English
Related Journal or Series Information: Nuclear Engineering and Design
Volume number: 2019
Issue number: 347
Start page: 67
End page: 85
Number of pages: 19
ISSN: 0029-5493
eISSN: 1872-759X
JUFO-Level of this publication: 3
Open Access: Not an Open Access publication

Abstract

Spargers are multi-hole injection pipes used in Boiling Water Reactors (BWR) and Generation III/III+ Pressurized Water Reactors (PWR) to condense steam in large water pools. During the steam injection, high pool surface temperatures induced by thermal stratification can lead to higher containment pressures compared with completely mixed pool conditions, the former posing a threat for plant safety. The Effective Heat Source (EHS) and Effective Momentum Source (EMS) models were previously developed and validated for the modelling of a steam injection through blowdown pipes. The goal of this paper is to extend the EHS/EMS model capabilities towards steam injection through multi-hole spargers. The models are implemented in ANSYS Fluent 17.0 Computational Fluid Dynamics (CFD) code and calibrated against the spargers experiments performed in the PPOOLEX and PANDA facilities, analysed by the authors in Gallego-Marcos et al. (2018b). CFD modelling guidelines are established for the adequate simulation of the pool behaviour. A new correlation is proposed to model the turbulent production and dissipation caused by buoyancy. Sensitivity studies addressing the effect of different assumptions on the effective momentum magnitude, profile, angle and turbulence are presented. Calibration of the effective momentum showed an inverse proportionality to the sub-cooling. Differences between the effective momentum calibrated for PPOOLEX and PANDA are discussed. Analysis of the calculated flow above the cold stratified layer showed that the erosion of the layer is induced by the action of turbulence rather than mean shear flow.


Last updated on 2020-20-03 at 10:03