Thermal-hydraulics is recognized as a key scientific issue in the development of innovative nuclear reactor systems. The European Thermal-Hydraulics of Innovative Nuclear Systems (THINS) project is focussed on this subject. The THINS project is sponsored by the European Commission and runs for four years from 2010 until 2014. The overall objectives of the THINS project are the development and validation of new physical models, improvement and qualification of numerical engineering tools and their application to innovative nuclear systems. This paper will highlight the on-going activities in this project related to supercritical water reactors (SCWR). An extensive literature review of existing experimental data and simulation techniques has led to the selection of innovative turbulence models and CFD approaches that have the potential to improve the accuracy of heat transfer simulations. Within the THINS project, such promising models and approaches are being tested in commercial, open-source, as well as in-house codes. With respect to SCWR, promising models are being implemented which should enable CFD techniques to predict heat transfer to supercritical water in complete fuel assemblies at acceptable accuracy. Innovative wall function models have to be selected, developed, and implemented to achieve this. Within the experimental ‘DeLight’ supercritical Freon loop of the Technical University of Delft, an LDA technique is used to provide flow field data within the near wall region of a heated rod. This data should serve to improve the understanding of near-wall heat transfer to supercritical fluids, to (further) develop or select appropriate CFD turbulence models and to validate them. The design of the experiment has been supported by using state-of-the-art existing CFD simulations.In some SCWR concepts, a multi-pass core is foreseen to allow intermediate mixing of the supercritical coolant flow. Within the DeLight facility, a mixing experiment will be set up in which up to three coolant jets may interact in a plenum. Measurements using PIV techniques will be used to analyse the turbulent flow field. On top of that, the feasibility of temperature measurements both in the fluid and in the solid structures to analyse thermal fatigue issues is studied. This paper will present the status of the on-going work in all the above described activities.

SCWR Related Activities within the European Thermal-Hydraulics for Innovative Nuclear Systems (THINS) Project

AMBROSINI, WALTER;
2013

Abstract

Thermal-hydraulics is recognized as a key scientific issue in the development of innovative nuclear reactor systems. The European Thermal-Hydraulics of Innovative Nuclear Systems (THINS) project is focussed on this subject. The THINS project is sponsored by the European Commission and runs for four years from 2010 until 2014. The overall objectives of the THINS project are the development and validation of new physical models, improvement and qualification of numerical engineering tools and their application to innovative nuclear systems. This paper will highlight the on-going activities in this project related to supercritical water reactors (SCWR). An extensive literature review of existing experimental data and simulation techniques has led to the selection of innovative turbulence models and CFD approaches that have the potential to improve the accuracy of heat transfer simulations. Within the THINS project, such promising models and approaches are being tested in commercial, open-source, as well as in-house codes. With respect to SCWR, promising models are being implemented which should enable CFD techniques to predict heat transfer to supercritical water in complete fuel assemblies at acceptable accuracy. Innovative wall function models have to be selected, developed, and implemented to achieve this. Within the experimental ‘DeLight’ supercritical Freon loop of the Technical University of Delft, an LDA technique is used to provide flow field data within the near wall region of a heated rod. This data should serve to improve the understanding of near-wall heat transfer to supercritical fluids, to (further) develop or select appropriate CFD turbulence models and to validate them. The design of the experiment has been supported by using state-of-the-art existing CFD simulations.In some SCWR concepts, a multi-pass core is foreseen to allow intermediate mixing of the supercritical coolant flow. Within the DeLight facility, a mixing experiment will be set up in which up to three coolant jets may interact in a plenum. Measurements using PIV techniques will be used to analyse the turbulent flow field. On top of that, the feasibility of temperature measurements both in the fluid and in the solid structures to analyse thermal fatigue issues is studied. This paper will present the status of the on-going work in all the above described activities.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/225545
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