Numerical study of the flow and heat transfer characteristics in a scale model of the vessel cooling system for the HTTR
1
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
The reactor cavity cooling system (RCCS) is a passive reactor safety system commonly present in the designs of High-Temperature Gas-cooled Reactors (HTGR) that removes heat from the reactor pressure vessel by means of natural convection and radiation. It is one of the factors responsible for ensuring that the reactor does not melt down under any plausible accident scenario. For the simulation of accident scenarios, which are transient phenomena unfolding over a span of up to several days, intermediate fidelity methods and system codes must be employed to limit the models’ execution time. These models can quantify radiation heat transfer well, but heat transfer caused by natural convection must be quantified with the use of correlations for the heat transfer coefficient. It is difficult to obtain reliable correlations for HTGR RCCS heat transfer coefficients experimentally due to such a system’s size. They could, however, be obtained from high-fidelity steady-state simulations of RCCSs. The Rayleigh number in RCCSs is too high for using a Direct Numerical Simulation (DNS) technique; thus, a Reynolds-Averaged Navier–Stokes (RANS) approach must be employed. There are many RANS models, each performing best under different geometry and fluid flow conditions. To find the most suitable one for simulating an RCCS, the RANS models need to be validated. This work benchmarks various RANS models against three experiments performed on the HTTR RCCS Mockup by the Japanese Atomic Energy Agency (JAEA) in 1993. This facility is a 1/6 scale model of a vessel cooling system (VCS) for the High Temperature Engineering Test Reactor (HTTR), which is operated by JAEA. Multiple RANS models were evaluated on a simplified 2d-axisymmetric geometry. They were found to reproduce the experimental temperature profiles with errors of up to 22% for the lowest temperature benchmark and 15% for the higher temperature benchmarks. The results highlight that the pragmatic turbulence models need to be validated for high Rayleigh natural convection-driven flows and improved accordingly, more publicly available experimental data of RCCS resembling experiments is needed and indicate that a 2d-axisymmetric geometry approximation is likely insufficient to capture all the relevant phenomena in RCCS simulations.
Abstract
The reactor cavity cooling system (RCCS) is a passive reactor safety system commonly present in the designs of High-Temperature Gas-cooled Reactors (HTGR) that removes heat from the reactor pressure vessel by means of natural convection and radiation. It is one of the factors responsible for ensuring that the reactor does not melt down under any plausible accident scenario. For the simulation of accident scenarios, which are transient phenomena unfolding over a span of up to several days, intermediate fidelity methods and system codes must be employed to limit the models’ execution time. These models can quantify radiation heat transfer well, but heat transfer caused by natural convection must be quantified with the use of correlations for the heat transfer coefficient. It is difficult to obtain reliable correlations for HTGR RCCS heat transfer coefficients experimentally due to such a system’s size. They could, however, be obtained from high-fidelity steady-state simulations of RCCSs. The Rayleigh number in RCCSs is too high for using a Direct Numerical Simulation (DNS) technique; thus, a Reynolds-Averaged Navier–Stokes (RANS) approach must be employed. There are many RANS models, each performing best under different geometry and fluid flow conditions. To find the most suitable one for simulating an RCCS, the RANS models need to be validated. This work benchmarks various RANS models against three experiments performed on the HTTR RCCS Mockup by the Japanese Atomic Energy Agency (JAEA) in 1993. This facility is a 1/6 scale model of a vessel cooling system (VCS) for the High Temperature Engineering Test Reactor (HTTR), which is operated by JAEA. Multiple RANS models were evaluated on a simplified 2d-axisymmetric geometry. They were found to reproduce the experimental temperature profiles with errors of up to 22% for the lowest temperature benchmark and 15% for the higher temperature benchmarks. The results highlight that the pragmatic turbulence models need to be validated for high Rayleigh natural convection-driven flows and improved accordingly, more publicly available experimental data of RCCS resembling experiments is needed and indicate that a 2d-axisymmetric geometry approximation is likely insufficient to capture all the relevant phenomena in RCCS simulations.
참고문헌 (37)
- Giorgio Locatelli, "Generation IV nuclear reactors: Current status and future prospects", Energy Policy, 61, pp.1503~1520 (2013)[DOI]
- Sümer Şahin, "Generation-IV reactors and nuclear hydrogen production", Int. J. Hydrogen Energy, 46(57), pp.28936~28948 (2021)[DOI]
- Zuoyi Zhang, "Current status and technical description of Chinese 2× 250MWth HTR-PM demonstration plant", Nucl. Eng. Des, 239(7), pp.1212~1219 (2009)[DOI]
- Taiju Shibata, "Present status of JAEA’s R&D toward HTGR deployment", Nucl. Eng. Des, 398, pp.111964~ (2022)[DOI]
- Hirofumi Ohashi, "A small-sized HTGR system design for multiple heat applications for developing countries", Int. J. Nucl. Energy, 2013 (2013)
- Eleonora Skrzypek, "Pre-conceptual design of the research high-temperature gas-cooled reactor TeResa for non-electrical applications", Energies, 15(6), pp.2084~ (2022)[DOI]
- Brian Mays, "Sensitivity of SC-HTGR conduction cooldown to reactor cavity cooling system failure", Nucl. Technol, 208(8), pp.1311~1323 (2022)[DOI]
- An Overview of Non-LWR Vessel Cooling Systems for Passive Decay Heat Removal, (Technical Letter Final Report), "Darius Lisowski", Argonne National Laboratory, ~ (2021)
- Khaled Talaat, "Design of a prototypical natural circulation waterbased reactor cavity cooling system (RCCS) for a pebble-bed generic FHR", Nucl. Eng. Des, 407, pp.112303~ (2023)[DOI]
- D. D. Lisowski, "Study on the behavior of an asymmetrically heated reactor cavity cooling system with water in single phase", Nucl. Technol, 183(1), pp.75~87 (2013)[DOI]
- Alexander J. Huning, "A review of recent advances in HTGR CFD and thermal fluid analysis", Nucl. Eng. Des, 373, pp.111013~ (2021)[DOI]
- Henrique Austregesilo, "ATHLET 3.3 user’s manual", ~ (2021)
- P. Emonot, "CATHARE-3: A new system code for thermal-hydraulics in the context of the NEPTUNE project", Nucl. Eng. Des, 241(11), pp.4476~4481 (2011)[DOI]
- "M-Tech Industrial, Flownex SE" (2023)[URL]
- Hong Lim, "GAMMA multidimensional multicomponent mixture analysis to predict air ingress phenomena in an HTGR", Nucl. Sci. Eng, 152, pp.87~97 (2006)[DOI]
- MELCOR Computer Code Manuals, Vol. 1: Primer and Users’ Guide, Version 2.1.6840, "L. L. Humphries", Sandia National Laboratories, ~, pp.Technical Report SAND2015-6691R (2015)
- U. S. NRC, "TRAC", RELAP Advanced Computational Engine (TRACE) V5.840USER’S MANUAL Volume 1: Input Specification, 2014
- P. G. Rousseau, "Code-to-code comparison for analysing the steady-state heat transfer and natural circulation in an air-cooled RCCS using GAMMA+ and flownex", Nucl. Eng. Des, 291, pp.71~89 (2015)[DOI]
- Marcos S. Sena, "Thermal-hydraulic behavior simulations of the reactor cavity cooling system (RCCS) experimental facility using Flownex", Nucl. Eng. Technol, 55(9), pp.3320~3325 (2023)[DOI]
- Benchmark Problem for IAEA Coordinated Research Program (CRP-3) on GCR Afterheat Removal (I), "Shoji Takada", JAEA, ~, pp.JAERI-Research 95-056 (1995)
- Final Project Report on RCCS Testing with Air-based NSTF, "Darius D", ~
- Report on Year-2 of Water NSTF Matrix Testing, "Darius Lisowski", ~
- Darius D. Lisowski, "Experimental observations of natural circulation flow in the NSTF", Nucl. Eng. Des, 306, pp.124~132 (2016)[DOI]
- Tomasz Kwiatkowski, "Towards the accurate prediction of axial flow and heat transfer in a tightly spaced bare rod bundle configuration", Nucl. Eng. Des, 403, pp.112119~ (2023)[DOI]
- Afaque Shams, "Towards the direct numerical simulation of a closely-spaced bare rod bundle", Ann. Nucl. Energy, 121, pp.146~161 (2018)[DOI]
- Ramiro Freile, "Improved natural convection heat transfer correlations for reactor cavity cooling systems of high-temperature gas-cooled reactors: From computational fluid dynamics to pronghorn", Ann. Nucl. Energy, 163, pp.108547~ (2021)[DOI]
- Angelo Frisani, "Computational fluid dynamics analysis of very high temperature gas-cooled reactor cavity cooling system", Nucl. Technol, 176(2), pp.238~259 (2011)[DOI]
- Angelo Frisani, "Computation fluid dynamics analysis of the reactor cavity cooling system for very high temperature gas-cooled reactors", Ann. Nucl. Energy, 72, pp.257~267 (2014)[DOI]
- Shoji Takada, "Establishment of reasonable 2-D model to investigate heat transfer and flow characteristics by using scale model of vessel cooling system for HTTR", Mech. Eng. J, 7(3), pp.19~00536 (2020)[DOI]
- Heat Transport and Afterheat Removal for Gas Cooled Reactors under Accident Conditions, "International Atomic Energy Agency", IAEA, ~, pp.IAEA TECDOC1163 (2001)
- Ansys Fluent Theory Guide, "ANSYS Inc", ANSYS Inc, ~, pp.Release 2022 R1 (2022)
- A. Shams, "High-performance computing for nuclear reactor design and safety applications", Nucl. Technol, 206(2), pp.283~295 (2020)[DOI]
- NIST Chemistry WebBook, "NIST Standard Reference Database Number 69", National Institute of Standards and Technology, ~ (1997)
- Y.S. Touloukian, "Thermophysical Properties of Matter, Vol. 3: Thermal Conductivity", pp.1970, IFI
- Y.S. Touloukian, "Thermophysical Properties of Matter, Vol. 11: Viscosity", pp.1970, IFI
- D. Y. Peng, "A new two-constant equation of state", Ind. Eng. Chem. : Fundam, 15, pp.59~64 (1976)
- D. Ganta, "Optical method for measuring thermal accommodation coefficients using a whispering-gallery microresonator", J. Chem. Phys, 135(8), pp.084313~ (2011)[DOI]