Transient heat transfer and crust evolution during debris bed melting process in the hypothetical severe accident of HPR1000
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In the late in-vessel phase of a nuclear reactor severe accident, the internal heat transfer and crust evolution during the debris bed melting process have important effects on the thermal load distribution along the vessel wall, and further affect the reactor pressure vessel (RPV) failure mode and the state of melt during leakage. This study coupled the phase change model and large eddy simulation to investigate the variations of the temperature, melt liquid fraction, crust and heat flux distributions during the debris bed melting process in the hypothetical severe accident of HPR1000. The results indicated that the heat flow towards the vessel wall and upper surface were similar at the beginning stage of debris melting, but the upward heat flow increased significantly as the development of the molten pool. The maximum heat flux towards the vessel wall reached 0.4 MW/m2 . The thickness of lower crust decreased as the debris melting. It was much thicker at the bottom region with the azimuthal angle below 20 and decreased rapidly at the azimuthal angle around 20e50. The maximum and minimum thicknesses were 2 and 90 mm, respectively. By contrast, the distribution of upper crust was uniform and reached stable state much earlier than the lower crust, with the thickness of about 10 mm. Moreover, the sensitivity analysis of initial condition indicated that as the decrease of time interval from reactor scram to debris bed driedout, the maximum debris temperature and melt fraction became larger, the lower crust thickness became thinner, but the upper crust had no significant change. The sensitivity analysis of in-vessel retention (IVR) strategies indicated that the passive and active external reactor vessel cooling (ERVC) had little effect on the internal heat transfer and crust evolution. In the case not considering the internal reactor vessel cooling (IRVC), the upper crust was not obvious
Abstract
In the late in-vessel phase of a nuclear reactor severe accident, the internal heat transfer and crust evolution during the debris bed melting process have important effects on the thermal load distribution along the vessel wall, and further affect the reactor pressure vessel (RPV) failure mode and the state of melt during leakage. This study coupled the phase change model and large eddy simulation to investigate the variations of the temperature, melt liquid fraction, crust and heat flux distributions during the debris bed melting process in the hypothetical severe accident of HPR1000. The results indicated that the heat flow towards the vessel wall and upper surface were similar at the beginning stage of debris melting, but the upward heat flow increased significantly as the development of the molten pool. The maximum heat flux towards the vessel wall reached 0.4 MW/m2 . The thickness of lower crust decreased as the debris melting. It was much thicker at the bottom region with the azimuthal angle below 20 and decreased rapidly at the azimuthal angle around 20e50. The maximum and minimum thicknesses were 2 and 90 mm, respectively. By contrast, the distribution of upper crust was uniform and reached stable state much earlier than the lower crust, with the thickness of about 10 mm. Moreover, the sensitivity analysis of initial condition indicated that as the decrease of time interval from reactor scram to debris bed driedout, the maximum debris temperature and melt fraction became larger, the lower crust thickness became thinner, but the upper crust had no significant change. The sensitivity analysis of in-vessel retention (IVR) strategies indicated that the passive and active external reactor vessel cooling (ERVC) had little effect on the internal heat transfer and crust evolution. In the case not considering the internal reactor vessel cooling (IRVC), the upper crust was not obvious
참고문헌 (28)
- G. Li, "Study on melt stratification and migration in debris bed using the moving particle semi-implicit method", Nucl. Eng. Des, 360, pp.110459~ (2020)
- J. Gao, "An axisymmetric multiphase moving particle semiimplicit method for simulation of 3D axisymmetric flow", Prog. Nucl. Energy, 149, pp.104259~ (2022)
- G. Li, "A review on MPS method developments and applications in nuclear engineering", Comput. Methods Appl. Mech. Eng, 367, pp.113166~ (2020)
- G. Li, "Numerical study of hydraulic fragmentation of melt jet in coolant : breakup length and melt-coolant contact area", Prog. Nucl. Energy, 145, pp.104131~ (2022)
- G. Li, "2D MPS analysis of hydrodynamic fine fragmentation of melt drop with initial steam film during fuelecoolant interaction", Ann. Nucl. Energy, 142, pp.107378~ (2020)
- G. Li, "Numerical study on melt drop collision and hydraulic fragmentation during FCI of a nuclear reactor severe accident", Nucl. Eng. Des, 370, pp.110862~ (2020)
- G. W. Parker, "Small scale BWR core debris eutectics formation and melting experiment", Nucl. Eng. Des, 121(3), pp.341~347 (1990)
- Late-phase Melt Progression Experiment: MP-2, "R. D. Gasser", Sandia National Laboratories, ~, pp.NUREG (1997), CR-6167
- M. Barrachin, "Late phase fuel degradation in the Ph"ebus FP tests", Ann. Nucl. Energy, 61, pp.36~53 (2013)
- MAAP-MELCOR Crosswalk Phase 1 Study, "D.L. Luxat", EPRI, 3002004449~ (2014)
- S. Nicolici, "Numerical analysis of debris melting phenomena during late phase CANDU 6 severe accident", Nucl. Eng. Des, 254, pp.272~279 (2013)
- CHI-THANH TRAN, "SIMULATION OF CORE MELT POOL FORMATION IN A REACTOR PRESSURE VESSEL LOWER HEAD USING AN EFFECTIVE CONVECTIVITY MODEL", Nuclear Engineering and Technology, 41(7), pp.929~944 (2009), 한국원자력학회
- C. Ji, "Non-uniform heat transfer suppression to enhance PCM melting by angled fins", Appl. Therm. Eng, 129, pp.269~279 (2018)
- P. C. Carman, "Fluid flow through granular beds", Trans. Inst. Chem. Enfrs, pp.150~166 (1937)
- S. Luo, "COPRA experiment and numerical research on the behavior of internally-heated melt pool with eutectic salt", Appl. Therm. Eng, 140, pp.313~324 (2018)
- K. Ge, "Transient behavior and maximum heat flux ratios of two-layer corium pool", Int. J. Therm. Sci, pp.179~ (2022)
- N. Kharoua, "LES study of the combined effects of groups of vortices generated by a pulsating turbulent plane jet impinging on a semi-cylinder", Appl. Therm. Eng, 114, pp.948~960 (2017)
- M. L. Shur, "A hybrid RANS-LES approach with delayed-DES and wall-modelled LES capabilities", Int. J. Heat Fluid Flow, 29, pp.1638~1649 (2008)
- L. Zhang, "Large eddy simulation for the thermal behavior of one-layer and two-layer corium pool configurations in HPR1000 reactor", Appl. Therm. Eng, 145, pp.38~47 (2018)
- C. T. Tran, "A study on the integral effect of corium material properties on melt pool heat transfer in a boiling water reactor", 14th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-14 (2011)
- Analysis of In-Vessel Retention and Ex-Vessel Fuel Coolant Interaction for AP1000, "H. Esmaili", Energy Research Inc., Nuclear Regulatory Commission, ~, pp.NUREF (2004), CR-6849
- L. Zhang, "Large eddy simulation on turbulent heat transfer in reactor vessel lower head corium pools", Ann. Nucl. Energy, 111, pp.293~302 (2018)
- C. T. Tran, "An approach to numerical simulation and analysis of molten corium coolability in a boiling water reactor lower head", Nucl. Eng. Des, 240(9), pp.2148~2159 (2010)
- W. Ma, "In-vessel melt retention of pressurized water reactors : historical review and future research needs", Engineering, 2(1), pp.103~111 (2016)
- D. Zhu, "Study on design and safety characteristics of cavity injection and cooling system for HPR1000 reactor", Nucl. Power Eng, 40(S1), pp.32~36 (2019)
- S. W. Churchill, "Free convection around immersed bodies", Heat Exch. Des. Handb, 2 (2002)
- W. M. Rohsenow, "Heat, Mass, and Momentum Transfer" (1961), Prentice-Hall
- B. R. Sehgal, "Stabilization and termination of severe accidents in LWRs", Nucl. Eng. Des, 236(19-21), pp.1941~1952 (2006)