Presentation Type
Invited
Start Date
16-12-2018 12:20 PM
Abstract
Understanding or modeling the role of stratification and mixing in the plena or containments of nuclear reactors is of prime significance to their safety analysis. Particularly, in case of liquid metal-cooled reactors, thermal stratification in the hot pools under off-normal transients is one of the least understood problems that have multi-physics effects on thermo- mechanics and reactor physics. This is primarily due to lack of high fidelity experimental data for validating CFD or system scale models, which are essential for improved understanding. A scaled liquid metal thermal-hydraulic facility with a scaled hot plenum has been developed at Kansas State University to study different transients. Experimental results obtained from Rayleigh Backscattering based Swept Wavelength Interferometry and Acoustic Backscattering instrumentation deployed in the liquid metal loop will be presented in this talk. Critical parametric estimates such as critical Rayleigh number and turbulent Prandtl number are identified from the experimental studies to classify the molecular, transitional and energetic regimes of mixing extent.
CFD codes using direct numerical simulations (DNS) or large eddy simulations (LES) have potential to be able to capture the physics of stratification or mixing with accuracy. However, it is well known that these approaches are computationally intensive and can not be used for sensitivity studies for design or safety analysis. On the other hand, system scale codes model the large enclosures such as containments or plena with the help of perfect mixing or1D coarse grained scalar transport. This talk will present the transient scenarios and demonstrate the performance of different models against experimental data.
Recommended Citation
Bindra, Hitesh; Ward, Brendan; Wilson, Graham; and Gairola, Abhinav (2018). "Stratification and Mixing in the Hot Plena of Liquid Metal-Cooled Reactors," Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety. https://newprairiepress.org/asemot/2018/fullprogram/47
Stratification and Mixing in the Hot Plena of Liquid Metal-Cooled Reactors
Understanding or modeling the role of stratification and mixing in the plena or containments of nuclear reactors is of prime significance to their safety analysis. Particularly, in case of liquid metal-cooled reactors, thermal stratification in the hot pools under off-normal transients is one of the least understood problems that have multi-physics effects on thermo- mechanics and reactor physics. This is primarily due to lack of high fidelity experimental data for validating CFD or system scale models, which are essential for improved understanding. A scaled liquid metal thermal-hydraulic facility with a scaled hot plenum has been developed at Kansas State University to study different transients. Experimental results obtained from Rayleigh Backscattering based Swept Wavelength Interferometry and Acoustic Backscattering instrumentation deployed in the liquid metal loop will be presented in this talk. Critical parametric estimates such as critical Rayleigh number and turbulent Prandtl number are identified from the experimental studies to classify the molecular, transitional and energetic regimes of mixing extent.
CFD codes using direct numerical simulations (DNS) or large eddy simulations (LES) have potential to be able to capture the physics of stratification or mixing with accuracy. However, it is well known that these approaches are computationally intensive and can not be used for sensitivity studies for design or safety analysis. On the other hand, system scale codes model the large enclosures such as containments or plena with the help of perfect mixing or1D coarse grained scalar transport. This talk will present the transient scenarios and demonstrate the performance of different models against experimental data.
