A study on modeling of boiling heat transfer in core debris bed of SFR
2
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
In case of a hypothetical severe accident in a Sodium-cooled Fast Reactor (SFR), coolability of the debris bed in the post-accident phase plays a vital role in mitigating the accident and ensuring the structural integrity of the reactor vessel. Few numerical studies are reported in literature, in which the boiling heat transfer in debris bed is expressed as equivalent heat conduction using similarity law between heat conduction and two-phase heat transfer. However, these studies assumed steady state mass conservation for the boiling zone and neglected the gravity force. Hence, a detailed study has been carried out for various particle sizes and porosities of SFR debris to investigate the influence of above considerations. The effect of gravity on debris bed coolability is studied using steady state model of Lipinski, which showed that gravity has a non-negligible effect, for particle size of 0.3 mm and porosity of 0.5. However, the gravitation force was found to have a negligible effect in dryout heat flux estimation for the bottom cooled configuration. A transient numerical model is developed for simulating the boiling phenomena in debris beds and validated with the published experimental results. The assumption of steady state mass conservation is verified by carrying out transient analysis, which indicated early prediction of the dryout inception. For time dependent heat generation case, the unsteady mass conservation predicted higher DHF compared to constant heat generation.
Abstract
In case of a hypothetical severe accident in a Sodium-cooled Fast Reactor (SFR), coolability of the debris bed in the post-accident phase plays a vital role in mitigating the accident and ensuring the structural integrity of the reactor vessel. Few numerical studies are reported in literature, in which the boiling heat transfer in debris bed is expressed as equivalent heat conduction using similarity law between heat conduction and two-phase heat transfer. However, these studies assumed steady state mass conservation for the boiling zone and neglected the gravity force. Hence, a detailed study has been carried out for various particle sizes and porosities of SFR debris to investigate the influence of above considerations. The effect of gravity on debris bed coolability is studied using steady state model of Lipinski, which showed that gravity has a non-negligible effect, for particle size of 0.3 mm and porosity of 0.5. However, the gravitation force was found to have a negligible effect in dryout heat flux estimation for the bottom cooled configuration. A transient numerical model is developed for simulating the boiling phenomena in debris beds and validated with the published experimental results. The assumption of steady state mass conservation is verified by carrying out transient analysis, which indicated early prediction of the dryout inception. For time dependent heat generation case, the unsteady mass conservation predicted higher DHF compared to constant heat generation.
참고문헌 (22)
- L. Gnanadhas, "Path-an experimental facility for natural circulation heat transfer studies related to Post Accident Thermal Hydraulics", Nucl. Eng. Des, 241, pp.3839~3850 (2011)[DOI]
- J. B. Rivard, "In-Reactor experiments on the cooling of fast reactor debris", Nucl. Technol, 46, pp.344~349 (2017)[DOI]
- R. J. Lipinski, "Particle bed heat removal with subcooled sodium : D-4 results and analysis", Nucl. Technol, 58, pp.369~378 (2017)[DOI]
- The D7 debris-bed experiment, "G. W. Mitchell", LMFBR, ~ (1983)
- The D10 experiment: coolability of UO2debris in sodium with downward heat removal, "G. W. Mitchell", ~ (1984)
- "Post Accident Debris Cooling : Proceedings of the Fifth Post Accident Heat Removal Information Exchange Meeting, July 28-30, 1982" (1983)[URL]
- I. Lindholm, "DHFexperiments with deep heterogeneous particle bed", Nucl. Eng. Des, 236, pp.2060~2074 (2006)[DOI]
- D. Magallon, "Pouring of 100-kg-scale molten UO2 into sodium", Nucl. Technol, 98, pp.79~90 (1992)[DOI]
- Model for Boiling and Dryout in Particle Beds, "R. Lipinski", LMFBR, ~ (1982)
- R. J. Lipinski, "Coolability model for postaccident nuclear reactor debris", Nucl. Technol, 65, pp.53~66 (1984)[DOI]
- M. Bürger, "Validation and application of the WABE code : investigations of constitutive laws and 2D effects on debris coolability", Nucl. Eng. Des, 236, pp.2164~2188 (2006)[DOI]
- H. Nakamura, "Method to calculate boiling and dryout in debris bed using a heat conduction code, Fast reactor safety", Proceedings of the International Topical Meeting, 2 (1985)
- B. Zhang, "Numerical investigation of DHF and heat transfer characteristics in core debris bed of SFR after severe accident", Nucl. Sci. Eng, 193, pp.115~130 (2019)[DOI]
- E. Matsuo, "Study on high-speed calculation of debris bed coolability for sodium-cooled fast reactors", Mech. Eng. J, 7 (2020)[DOI]
- S. Ergun, "Fluid flow through randomly packed columns and fluidized beds", Ind. Eng. Chem, 41, pp.1179~1184 (1949)[DOI]
- M. C. Leverett, "Capillary behavior in porous solids", OR Trans, 142(1), pp.152~169[DOI]
- G. Hofmann, "A Quasi-Steady-State Approximation to the Transient Dryout Behavior in Debris Beds", International Meeting on Light-Water Reactor Severe Accident Evaluation (1983)
- G. Hofmann, "On the location and mechanisms of dryout in top-fed and bottom-fed particulate beds", Nucl. Technol, 65(1983), pp.36~45 (1983)
- A. W. Reed, "The Effect of Channeling on the Dryout of Heated Particulate Beds Immersed in a Liquid Pool", Ph. D., pp.1982
- K. Hu, "On the measurement and mechanism of dryout in volumetrically heated coarse particle beds", Int. J. Multiphas. Flow, 17(4), pp.519~532 (1991)
- V. X. Tung, "A hydrodynamic model for two-phase flow through porous media", Int. J. Multiphas. Flow, 14(1), pp.47~65 (1988)
- T. Schulenberg, "An improved model for two-phase flow through beds of coarse particles", Int. J. Multiphas. Flow, 13(1), pp.87~97 (1987)