Simulation of Core Melt Pool Formation in a Reactor Pressure Vessel Lower Head Using an Effective Convectivity Model (original) (raw)

Abstract

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The Effective Convectivity Model (ECM) has been developed to analyze core melt pool formation in the lower plenum of Light Water Reactors (LWRs) during severe accidents. This study extends the ECM by addressing phase-change dynamics and incorporates a new Phase-change ECM (PECM), validated against experimental and CFD data. Results demonstrate PECM's efficacy in modeling heat transfer and convective behavior in complex reactor geometries, contributing to improved safety evaluations in nuclear reactor operations.

FAQs

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What explains the effectiveness of the Phase-change ECM in simulating melt pool dynamics?add

The Phase-change ECM (PECM) effectively simulates melt pool dynamics by utilizing a linear dependency of characteristic velocity on liquid fraction, resulting in strong agreement with experimental and CFD data, particularly in terms of heat transfer coefficients.

How does mushy zone velocity impact heat transfer in melt pools?add

The study identifies that mushy zone characteristic velocities significantly influence heat transport dynamics, with variations in model parameters leading to discrepancies in predicted pool temperatures by up to 25% in some simulation scenarios.

When were the RASPLAV and SIMECO experiments conducted, and what did they reveal?add

The RASPLAV project and SIMECO experiments were conducted throughout the 1990s and early 2000s, revealing that heat transfer correlations from simulant tests apply to corium behaviors, validating methods for predicting natural convection in melt pools.

What numerical methods are compared in this research for modeling phase-change problems?add

The paper compares strong numerical solutions applying finite-difference and finite-element techniques with weak numerical solutions using fixed grid methods, highlighting the efficacy of the enthalpy formulation in computational efficiency for phase-change scenarios.

What are the practical implications of adopting the PECM for reactor pressure vessel safety?add

The PECM’s ability to simulate complex heat transfer scenarios in lower plenum geometries enhances predictive capabilities for thermal loads on reactor structures, aiding in the development of accident management strategies during severe reactor incidents.

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References (34)

  1. B. R. SEHGAL, V. A. BUI, T. N. DINH and R. R. NOURGALIEV, "Heat Transfer Process in Reactor Vessel Lower Plenum during A Late Phase of In-Vessel Core Melt Progression", J. Advances in Nuclear Science and Technology, Vol. 26, pp. 103-135, 1998.
  2. C. T. TRAN, T. N. DINH, "Analysis of Melt Pool Heat Transfer in a BWR Lower Head", Transactions of ANS Winter Meeting, Albuquerque, NM, USA, November 12- 18, Vol. 95, pp. 629-631, 2006.
  3. "MAAP4 Users Manual", Fauske Associated Inc., Vol. 2, 1999.
  4. R. O. GAUNTT et al., "MELCOR Computer Code Manual, Core (COR) Package Reference Manuals", NUREG/CR- 6119, Vol. 2, Rev.2, Version 1.8.6, September 2005.
  5. C. T. TRAN, T. N. DINH, "An Effective Convectivity Model for Simulation of In-Vessel Core Melt Progression in Boiling Water Reactor", 2007 International Congress on Advances in Nuclear Power Plants (ICAPP 2007), Nice Acropolis, France, May 13-18, 2007.
  6. V. A. BUI and T. N. DINH, "Modeling of Heat Transfer in Heated-Generating Liquid Pools by an Effective Diffusivity- Convectivity Approach", Proceedings of 2 nd European Thermal-Sciences Conference, Rome, Italy, pp.1365-1372, 1996.
  7. F. B. CHEUNG , S.W. SHIAH, D.H. CHO and M.J. TAN, "Modeling of Heat Transfer in A Horizontal Heat-Generating Layer by An Effective Diffusivity Approach". ASME HTD- Vol. 192, pp.55-62, 1992.
  8. UDF Manual, Fluent 6.2 Documentation, Fluent Inc. 2005.
  9. V. ASMOLOV, N. N. PONOMAREV-STEPNOY, V. STRIZHOV, B. R. SEHGAL, "Challenges Left in the Area of In-Vessel Melt Retention", J. Nuclear Engineering and Design, Vol. 209, pp. 87-96, 2001.
  10. V. G. ASMOLOV, S. V. BECHTA, V. B. KHABENSKY et al., "Partitioning of U, Zr and Fe between Molten Oxidic and Metallic Corium", Proceeding of MASCA Seminar 2004, Aix-en-Provence, France, 2004.
  11. V. STRIZHOV, V. ASMOLOV, "Major Outcomes of the RASPLAV Project", RASPLAV Seminar 2000, Munich, November, 2000.
  12. B. R. SEHGAL, V. A. BUI, T. N. DINH, J. A. GREEN, G. KOLB, "SIMECO Experiments on In-Vessel Melt Pool Formation and Heat Transfer with and without a Metallic Layer", Proceedings of In-Vessel Core Debris Retention and Coolability Workshop, Garching, Germany, March 3- 6, pp. 205-213, 1998.
  13. A. MIASSOEDOV, T. CRON, J. FIOT, S. SCHMIDT- STIEFEL, T. WENZ, I. IVANOV, D. POPOV, "Results of the LIVE-L1 Experiment on Melt Behavior in RPV Lower Head Performed within the LACOMERA Project at the Forschungszentrum Karlsruhe", Proceedings of 15 th International Conference on Nuclear Engineering Nagoya (ICONE), Japan, April 22-26, 2007.
  14. M. HELLE, O. KYMALAINEN and H. TUOMISTO, "Experimental Data on Heat Flux Distribution from a Volumetrically Heated Pool with Frozen Boundaries", Proceedings of In-Vessel Core Debris Retention and Coolability Workshop, Garching, Germany, March 3-6, pp. 173-183, 1998.
  15. L. BERNAZ, J.-M. BONNET, B. SPINDLER, C. VILLERMAUX, "Thermal Hydraulic Phenomena in Corium Pools: Numerical Simulation with TOLBIAC and Experimental Validation with BALI", Proceedings of In- Vessel Core Debris Retention and Coolability Workshop, Garching, Germany, March 3-6, pp. 185-193, 1998.
  16. M. OKADA, "Analysis of Heat Transfer during Melting from a Vertical Walls", Int. J. Heat Mass Transfer, Vol. 27 (11), pp. 2057-2066, 1984.
  17. C. J. HO and S. CHEN, "Numerical Simulation of Melting of Ice around a Horizontal Cylinder", Int. J. Heat Mass Transfer, Vol. 29 (9), pp. 1359-1368, 1986.
  18. N. SHAMSUNDAR, E. M. SPARROW, "Analysis of Multidimensional Conduction Phase change Via the Enthalpy Model", J. Heat Transfer, Vol. 97 (3), pp. 333-340, 1975.
  19. V. R. VOLLER and C. PRAKASH, "A Fixed Grid Numerical Modelling Methodology for Convection-Diffusion Mushy Region Phase-Change Problems", J. Heat Mass Transfer, Vol. 30 (8), pp.1709-1719, 1987.
  20. Y. CAO, A. FAGHRI and W. S. CHANG, "A Numerical Analysis of Stefan Problems for Generalized Multi- Dimensional Phase-Change Structures Using the Enthalpy Transforming Model", Int. J. Heat Mass Transfer, Vol. 32 (7), pp. 1289-1298, 1989.
  21. P. J. PRESCOTT, F. P. INCROPERA, D. R. GASKELL, "Convective-Transport Phenomena and Macrosegregation during Solidification of a Binary Metal Alloy. 2. Experiments and Comparisons with Numerical Predictions", J. Heat Transfer-Transactions of the ASME, Vol. 116 (3), pp. 742- 749, Aug. 1994.
  22. B. BINET, M. LACROIX, "Numerical Study of Natural- Convection-Dominated Melting inside Uniformly and Discretely Heated Rectangular Cavities", Numerical Heat Transfer Part A-Applications, Vol. 33 (2), pp. 207-224, 1998.
  23. V. R. VOLLER and A. D. BRENT, "Modelling the Mushy Region in a Binary Alloy", App. Math Modelling, Vol. 14, pp. 320-326, 1990.
  24. T. W. CLYNE, "Numerical Modeling of Directional Solidification of Metallic Alloys", J. Metal Science, Vol. 16 (9), pp. 441-450, 1982.
  25. V. R. VOLLER and C. R. SWAMINATHAN, "General Source-Based Method for Solidification Phase Change", J. Numerical Heat Transfer, Part B, Vol. 19, pp. 175-189, 1991.
  26. U. STEINBERNER and H.H. REINEKE, "Turbulent Buoyancy Convection Heat Transfer with Internal Heat Sources". Proceedings of the 6 th Int. Heat Transfer Conference, Toronto, Canada, Vol.2, pp.305-310, 1978.
  27. O. KYMALAINEN, H. TUOMISTO, T. G. THEOFANOUS, "In-Vessel Retention of Corium at the Loviisa Plant", J. Nuclear Engineering and Design, Vol. 169, pp. 109-130, 1997.
  28. T. G. THEOFANOUS, M. MAGUIRE, S. ANGELINI, T. SALMASSI, "The First Results from the ACOPO Experiment", J. Nuclear Engineering and Design, Vol. 169, pp.49-57, 1997.
  29. T. C. CHAWLA and S. H. CHAN, "Heat Transfer From Vertical/Inclined Boundaries of Heat-Generating Boiling Pools", J. Heat Transfer, Vol. 104, pp.465-473, 1982.
  30. M. RAMACCIOTTI, C. JOURNEAU, F. SUDREAU, G. COGNET, "Viscosity Models for Corium Melts", J. Nuclear Engineering and Design, Vol. 204, pp. 377-389, 2001.
  31. F. A. KULACKI and A. A. EMARA, "Steady and Transient Thermal Convection in a Fluid Layer with Uniform Volumetric Energy Sources", J. Fluid Mech., Vol. 83, part 2, pp.375- 395, 1977.
  32. R. R. NOURGALIEV, T. N. DINH, "The Investigation of Turbulence Characteristics in an Internally-Heated Unstably- Stratified Fluid Layer", J. Nuclear Engineering and Design, Vol. 178, pp. 235-258, 1997.
  33. T. G. THEOFANOUS, C. LIU, S. ADDITON, S. ANGELINI, O. KYMALAINEN, T. SALMASSI, "In-vessel Coolability and Retention of a Core Melt", DOE/ID-1046, November 1994.
  34. H.-G. WILLSCHUETZ, E. ALTSTADT, B. R. SEHGAL, F.-P. WEISS, "Recursively Coupled Thermal and Mechanical FEM -Analysis of Lower Plenum Creep Failure Experiments", Annals of Nuclear Energy, Vol. 33, pp.126-148, 2006.