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Neutronics modeling of bubbles in bubbly flow regime in boiling water reactors

  • Turkmen, Mehmet (Nuclear Engineering Department, Faculty of Engineering, Hacettepe University, Beytepe Campus) ;
  • Tiftikci, Ali (Nuclear Engineering Department, Faculty of Engineering, Sinop University)
  • Received : 2018.04.06
  • Accepted : 2019.02.26
  • Published : 2019.06.25

Abstract

This study mainly focused on the neutronics modeling of bubbles in bubbly flow in boiling water reactors. The bubble, ring and homogenous models were used for radial void fraction distribution. Effect of the bubble and ring models on the infinite multiplication factor and two-group flux distribution was investigated by comparing with the homogenous model. Square pitch unit cell geometry was used in the calculations. In the bubble model, spherical and non-spherical bubbles at random positions, sizes and shapes were produced by Monte Carlo method. The results show that there are significant differences among the proposed models from the viewpoint of physical interaction mechanism. For the fully-developed bubbly flow, $k_{inf}$ is overestimated in the ring model by about $720{\pm}6pcm$ with respect to homogeneous model whereas underestimated in the bubble model by about $-65{\pm}9pcm$ with a standard deviation of 15 pcm. In addition, the ring model shows that the coolant must be separated into regions to properly represent the radial void distribution. Deviations in flux distributions principally occur in certain regions, such as corners. As a result, the bubble model in modeling the void fraction can be used in nuclear engineering calculations.

Keywords

References

  1. S. Hosakawa, K. Hyashi, A. Tomiyama, Void distribution and bubble motion in bubbly flows in a 4${\times}$4 rod bundle. Part I: Experiments, J. Nucl. Sci. Technol. 51 (2) (2014) 220-230. https://doi.org/10.1080/00223131.2013.862189
  2. A. Tomiyama, Y. Nakahara, Y. Adachi, S. Hosokawa, Shapes and rising velocities of single bubbles rising through an inner subchannel, J. Nucl. Sci. Technol. 40 (3) (2003) 136-142. https://doi.org/10.1080/18811248.2003.9715343
  3. R.H.S. Winterton, J.S. Munaweera, Bubble size in two-phase gas-liquid bubbly flow in ducts, Chem. Eng. Process 40 (2001) 437-447. https://doi.org/10.1016/S0255-2701(00)00142-2
  4. T. Hibiki, R. Situ, Y. Mi, M. Ishii, Modelling of bubble-layer thickness for formulation of one-dimensional interfacial area transport equation in subcooled boiling two-phase flow, Int. J. Heat Mass Transf. 46 (2003) 1409-1423. https://doi.org/10.1016/S0017-9310(02)00418-0
  5. J.E. Julia, T. Hibiki, M. Ishii, B.-J. Yun, G.-C. Park, Drift-flux model in a subchannel of rod bundle geometry, Int. J. Heat Mass Transf. 52 (2009) 3032-3041. https://doi.org/10.1016/j.ijheatmasstransfer.2009.02.012
  6. O. Marfaing, M. Guingo, J. Lavieville, G. Bois, N. Mechitoua, N. Merigoux, S. Mimouni, An analytical relation for the void fraction distribution in a fully developed bubbly flow in a vertical pipe, Chem. Eng. Sci. 152 (2016) 579-585. https://doi.org/10.1016/j.ces.2016.06.041
  7. T. Ikehara, Y. Kudo, M. Tamitani, M. Yamamoto, Effect of subchannel void fraction distribution on lattice physics parameters for boiling water reactor fuel bundles, J. Nucl. Sci. Technol. 45 (12) (2008) 1237-1251. https://doi.org/10.1080/18811248.2008.9711912
  8. T. Ama, H. Hyoudou, T. Takeda, Effect of radial void distribution within fuel assembly on assembly neutronic characteristics, J. Nucl. Sci. Technol. 39 (1) (2002) 90-100. https://doi.org/10.3327/jnst.39.90
  9. A. Bennett, N. Martin, M. Avramova, K. Ivanov, Impact of radial void fraction distribution on boiling water reactor lattice physics calculations: application to AREVA's next generation BWR fuel assembly, the $ATRIUM^{TM}$ 11 design, in:PHYSOR 2016, Sun Valley, Idaho, May 1-5, 2016.
  10. F. Jatuff, F.D. Giust, J. Krouthen, S. Helmersson, R. Chawla, Effects of void uncertainties on the void reactivity coefficient and pin power distributions for a 10x10 BWR assembly, Ann. Nucl. Energy 33 (2006) 119-125. https://doi.org/10.1016/j.anucene.2005.09.007
  11. NEA, NUPEC BWR Full-Size Fine-mesh Bundle Test (BFBT) Benchmark: Volume 1-Specifications, vol. 5, NEA/NSC/DOC, 2005. OECD/NEA, 2006.
  12. NEA, Benchmark for Uncertainty Analysis in Modelling (UAM) for the Design, Operation and Safety Analysis of LWRs: Specification and Support Data for Neutronics Cases (Phase I), vol. I, NEA/NSC/DOC, 2013, 7. OECD/NEA, 2013.
  13. NEA, Boiling Water Reactor Turbine Trip (TT) Benchmark, Volume I: Final Specifications, vol. 1, NEA/NSC/DOC, 2001. OECD/NEA, 2001.
  14. M. Ishii, T. Hibiki, Thermo-Fluid Dynamics of Two-phase Flow, second ed., Springer, New York, 2011.
  15. S. Levy, Two-Phase Flow in Complex Systems, John Wiley & Sons, New York, 1999.
  16. N.E. Todreas, M.S. Kazimi, Nuclear Systems I: Thermal Hydraulic Fundamentals, second ed., CRC Press, Taylor & Francis Group, USA, 2012.
  17. R. Luo, Q. Song, X. Yang, Z. Wang, Developed 'laminar' bubbly flow with nonuniform bubble sizes, Sci. China, Ser. E 44 (1) (2001) 47-54. https://doi.org/10.1007/BF02916725
  18. D.B. Pelowitz, A.J. Fallgren, G.E. McMath, MCNP6 User's Manual, Code Version 6.1.1beta, Manual Rev. 0, LA-CP-14-00745, Rev. 0, 2014.