Attila Kiss

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Verified

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• Ph.D.
• Associate Professor at Budapest University of Technology and Economics

BME, as a consortium member, is participating in the ECC-SMART project, which has been awarded an EU/EURATOM/H2020 grant in 2020, and is researching the development of a supercritical water-cooled small modular reactor concept called SCW-SMR. This paper summarizes the research work carried out so far at BME within the framework of the project. Firs...

Inherently poorer moderation in SCWRs due to average density lower than in LWRs and the resulted spectral shift can be useful when we apply thorium fuel cycle instead of uranium-plutonium one, according to an on-going study in BME NTI. Upon this conclusion, a thorium fueled SCWR design (Th-SCWR) has been proposed by BME NTI. In current feasibility...

The application of relatively simple and cheap wrapped wire spacer in the European supercritical water-cooled reactor (HPLWR) has been proposed in order to provide enhanced heat transfer in the fuel assembly without unacceptable penalty in pressure loss. The wires cause twisting flow in the fuel assembly, which means the coolant flows not only stra...

FOREWORD The supercritical water cooled reactor (SCWR) is an innovative concept that operates at a pressure higher than the thermodynamic critical point of water, allowing the core outlet coolant temperature to be much higher than that of the current generation of WCRs. The key technological advantages of the SCWR include its high thermal efficien...

The application of relatively simple and cheap wrapped wire spacer in the European supercritical-water-cooled reactor has been proposed in order to provide enhanced heat transfer in the fuel assembly without unacceptable penalty in pressure loss. The wires cause twisting flow in fuel assembly, which means the coolant flows not only straight in the...

In this dissertation, I present my doctoral research which was about thermal hydraulic investigations of the coolant (supercritical (pressure) water, SCW) flow in Supercritical Water-cooled Reactor (SCWR) relevant geometries. This research was started during the elaboration of my MSc thesis (February-June 2006). At the beginning, my former Supervis...

Two computational fluid dynamic (CFD) benchmarks have been performed to assess the prediction accuracy and sensitivity of CFD codes for heat transfer in different geometries. The first benchmark focused on heat transfer to water in a tube (first benchmark), while the second benchmark covered heat transfer to water in two different channel geometrie...

Two blind Computational Fluid Dynamic (CFD) benchmarks have been performed to assess the prediction accuracy of current CFD codes used by the participants against heat transfer data in different geometries. CFD calculations have been performed by the participants for tube (1st benchmark) and two different channel geometries (2nd benchmark). In the...

The thermal hydraulics of supercritical water under forced-, mixed convection and natural circulation conditions is not fully understood. In order to study the thermal hydraulic behaviour of this fluid under natural circulation conditions a small size, closed experimental loop has been designed and built. The thermal hydraulic phenomenon occurring...

The wrapped wire spacer has been considered as an alternative spacer device in Generation IV reactor concepts just like in the European SCWR, in the HPLWR concept. In the wrapped wire spacer concept practically each fuel rod gets a wire wrapped around it. Thus on one hand radial velocity components, strong mixing (heat, momentum and mass transfer),...

A konvencionális erőművi technológiában bevett gyakorlatnak számító kapcsolt energiatermelés hamarosan létrejöhet nukleáris hőforrással is. Ennek megvalósítására jelenleg is kutatások folynak a negyedik generációs reaktorok közé tartozó magas hőmérsékletű reaktor (HTR) koncepció alkalmazásával. Ezzel a reaktorral akár 1000 °C-os kilépő primerköri h...

Heat transfer in supercritical water reactors (SCWRs) shows a complex behavior, especially when the temperatures of the water are near the pseudocritical value. For example, a significant deterioration of heat transfer may occur, resulting in unacceptably high cladding temperatures. The underlying physics and thermodynamics behind this behavior are...

The Supercritical Water Reactor (SCWR) is one of the six reactor concepts being investigated under the framework of the Generation IV International Forum (GIF). One of the major challenges in the development of a SCWR is to develop materials for the fuel and core structures that will be sufficiently corrosion-resistant to withstand supercritical wa...

The Supercritical Water Reactor (SCWR) is one of the six reactor concepts being investigated under the framework of the Generation IV International Forum (GIF). One of the major challenges in the development of a SCWR is to develop materials for the fuel and core structures that will be sufficiently corrosion-resistant to withstand supercritical wa...

Heat transfer in supercritical water reactors (SCWR) shows a complex behavior, especially when the temperatures of the water are near the pseudo-critical value. For example, a significant deterioration of heat transfer may occur, resulting in unacceptably high cladding temperatures. The underlying physics and thermodynamics behind this behavior is...

This paper describes the first steps of the realization of a natural circulation loop cooled by supercritical water. The thermal hydraulics of supercritical water is not fully understood. The thermal hydraulic phenomenon in the loop is intended to be measured by thermocouples, absolute and differential pressure transducers, flow meter and simultane...

Three dimensional CFD simulations have been performed for supercritical water flow within a fuel bundle with 4 rods in a square arrangement. To ensure spacing between the rods, the design of the bundle uses thin wires wrapped clockwise around each rod. This geometry is presently investigated in the framework of EU supported FP-7 project of SCWR Fue...

This paper describes the first steps of the realization of a natural circulation loop cooled by supercritical water. The thermalhydraulics of supercritical water is not fully understood. The thermalhydraulic phenomenon in the loop is intended to be measured by thermocouples, absolute and differential pressure transducers, flow meter and simultaneou...

The supercritical pressure water is considered as the coolant in the primary loop of the presently developed Generation IV Supercritical pressure Water-cooled Reactors (SCWRs). The thermal hydraulics of this coolant is not fully understood though it is essentially needed for basic design and nuclear safety reasons. During the last decade, it has be...

The supercritical pressure water is considered as the coolant in the primary loop of the presently developed Generation IV Supercritical pressure Water-cooled Reactors (SCWRs). The thermal hydraulics of this coolant is not fully understood though it is essentially needed for basic design and nuclear safety reasons. During the last decade, it has be...

This paper describes the first steps of the realization of a natural circulation loop cooled by supercritical water. The thermalhydraulics of supercritical water is not fully understood. The thermalhydraulic phenomenon in the loop is intended to be measured by thermocouples, absolute and differential pressure transducers, flow meter and simultaneou...

Three dimensional computational-fluid-dynamics simulations are performed for the fluid flow within a 40 rod fuel bundle in a square arrangement with a central moderator channel. To ensure spacing between the rods the design of the bundle uses thin wires wrapped counter-clockwise around each rod. This geometry is presently investigated in the framew...

As recent studies prove in contrast to “classical” dimensional analysis, whose application is widely described in heat transfer textbooks despite its poor results, the less well known and used discriminated dimensional analysis approach can provide a deeper insight into the physical problems involved and much better results in all cases where it is...

Three dimensional computational-fluid-dynamics simulations are performed for the fluid flow within a 40 rod fuel bundle in a square arrangement with a central moderator channel. To ensure spacing between the rods the design of the bundle uses thin wires wrapped counter-clockwise around each rod. This geometry is presently investigated in the framew...

Computational fluid dynamics (CFD) codes have become promising tools for the investigation of thermal hydraulics in revolutionary reactor concepts in the last decade. In Reynolds-averaged Navier-Stokes calculations, the CFD codes (for example, the ANSYS CFX code used here) use turbulence modeling, wall functions, and other approaches. Therefore, th...

The increasingly used supercritical pressure water (SCW) is a special coolant for conventional fossil fired power plant and newly intended to use for Supercritical pressure Water cooled Reactors (SCWRs) in the near future. Five experimental cases have been selected to serve as test cases for CFD validations using Reynolds Averaged Navier-Stokes (RA...

Three dimensional computational-fluid-dynamics simulations are performed for the fluid flow within a 40 rod fuel bundle in a square arrangement with a central moderator channel. To ensure spacing between the rods the design of the bundle uses thin wires wrapped counter-clockwise around each rod. This geometry is presently investigated in the framew...

The Supercritical or High-Performance Light-Water Reactor (HPLWR) is presently being investigated in Europe, Japan and other countries. In the cooling channels of the reactor core water at supercritical pressure of 25 MPa is strongly heated above the pseudo-critical temperature of 385°C. For the understanding of the flow and heat transfer in the co...

The Supercritical or High-Performance Light-Water Reactor (HPLWR) is presently being investigated in Europe, Japan and other countries. In the cooling channels of the reactor core water at supercritical pressure of 25 MPa is strongly heated above the pseudo-critical temperature. For the understanding of the flow and heat transfer in the cooling and...

CFD codes become promising tools for the investigation of thermohydraulics in revolutionary reactor concepts in the latest decade. In RANS (Reynolds Averaged Navier-Stokes) calculations the commercial CFD codes (for example the ANSYS CFX) use turbulence modelling, wall functions and other approaches. Therefore the accuracy of CFD codes for water fl...

Three dimensional computational-fluid-dynamics simulations are performed for the fluid flow within a 40 rod fuel bundle in a square arrangement with a central moderator channel. To ensure spacing between the rods, the design of the bundle uses thin wires wrapped counter-clockwise around each rod. This geometry is presently investigated in the frame...

Validation of the ANSYS CFX commercial CFD code for calculating the supercritical pressure water flow and also the meshing parameters' sensitivity study of the corresponding model are presented in this paper. Measurement data for heat transfer to supercritical water in a vertical smooth-bore tube published by Swenson and et al. were compared with R...