An advanced core design for a soluble-boron-free small modular reactor ATOM with centrally-shielded burnable absorber

  • Nguyen, Xuan Ha (Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST)) ;
  • Kim, ChiHyung (Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST)) ;
  • Kim, Yonghee (Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST))
  • Received : 2018.07.14
  • Accepted : 2018.10.17
  • Published : 2019.04.25


A complete solution for a soluble-boron-free (SBF) small modular reactor (SMR) is pursued with a new burnable absorber concept, namely centrally-shielded burnable absorber (CSBA). Neutronic flexibility of the CSBA design has been discussed with fuel assembly (FA) analyses. Major design parameters and goals of the SBF SMR are discussed in view of the reactor core design and three CSBA designs are introduced to achieve both a very low burnup reactivity swing (BRS) and minimal residual reactivity of the CSBA. It is demonstrated that the core achieves a long cycle length (~37 months) and high burnup (~30 GWd/tU), while the BRS is only about 1100 pcm and the radial power distribution is rather flat. This research also introduces a supplementary reactivity control mechanism using stainless steel as mechanical shim (MS) rod to obtain the criticality during normal operation. A further analysis is performed to investigate the local power peaking of the CSBA-loaded FA at MS-rodded condition. Moreover, a simple $B_4C$-based control rod arrangement is proposed to assure a sufficient shutdown margin even at the cold-zero-power condition. All calculations in this neutronic-thermal hydraulic coupled investigation of the 3D SBF SMR core are completed by a two-step Monte Carlo-diffusion hybrid methodology.



Supported by : National Research Foundation of Korea (NRF)


  1. GIF and Generation-iv, 2012.
  2. P.P. Povinec, K. Hirose, M. Aoyama, 3-Fukushima Accident, Elsevier, Boston, 2013, pp. 55-102.
  3. V. Nian, The prospects of small modular reactors in Southeast Asia, Prog. Nucl. Energy 98 (2017) 131-142.
  4. M.D. Carelli, D.T. Ingersoll, Handbook of Small Modular Nuclear Reactors, Elsevier, Boston, 2014.
  5. S.E. Hirdaris, et al., Considerations on the potential use of Nuclear Small Modular Reactor (SMR) technology for merchant marine propulsion, Ocean Eng. 79 (2014) 101-130.
  6. S.M. Modro, et al., Multi-application Small Light Water Reactor Final Report, Bechtel BWXT, Idaho, 2003.
  7. M.K. Rowinski, T.J. White, J. Zhao, Small and Medium sized Reactors (SMR): a review of technology, Renew. Sustain. Energy Rev. 44 (2015) 643-656.
  8. EPRI, Elimination of Soluble Boron for a New PWR Design, 1989 report document EPRI-NP-6536.
  9. M.S. Yahya, H. Yu, Y.H. Kim, Burnable absorber-integrated Guide Thimble (BigT) - I: design concepts and neutronic characterization on the fuel assembly benchmarks, J. Nucl. Sci. Technol. 53 (7) (2016) 1048-1060.
  10. M.S. Yahya, Y.H. Kim, An innovative core design for a soluble-boron-free small pressurized water reactor, Int. J. Energy Res. (2017) 1-9.
  11. J. Kim, H. Cho, M. Do, S. K, Use of Solid Pyrex Rod for Conceptual Soluble Boron Free SMR, Transaction of the American Nuclear Society, Las Vegas, 2016.
  12. J.J. Ingremeau, C.M. Flexblue, Core design: optimization of fuel poisoning for a soluble boron free core with full or half core refueling, EPJ Nucl. Sci. Tech. (2015) 1-11.
  13. F. Franceschini, B. Petrovic, A Soluble Boron Free Core Design for IRIS-50, vol. 100, Transaction of American Nuclear Society, 2009, pp. 553-555.
  14. A.E. Abelhameed, H.U. Rehman, Y. Kim, A physics study for passivelyautonomous daily load-follow operation in soluble-boron-free SMR, in: Proceedings of ICAPP, Fukui & Tokyo, Japan, 2017.
  15. A.E. Abdelhameed, X.H. Nguyen, Y. Kim, Feasibility of passive autonomous frequency control operation in a Soluble-Boron-Free small PWR, Ann. Nucl. Energy 116 (2018) 319-333.
  16. M.S. Yahya, Y.H. Kim, Burnable absorber-integrated guide thimble (BigT)e II: application to 3D PWR core design, J. Nucl. Sci. Technol. 53 (10) (2016) 1521-1527.
  17. J. Leppanen, M. Pusa, T. Viitanen, V. Valtavirta, T. Kaltiaisenaho, The Serpent Monte Carlo code: status, development and applications in 2013, Annals of Nuclear Engergy 82 (2015) 142-150.
  18. B. Cho, S. Yuk, N.Z. Cho, Y. Kim, User's Manual for the Rectangular Three-dimensional Diffusion Nodal Code COREDAX-2 Version 1.8, KAIST, Daejeon, Korea, 2016.
  19. M.S. Yahya, Y.H. Kim, A New Approach for a High-performance Soluble-Boron-free PWR Core, PhD Thesis, KAIST, Daejeon, 2016.
  20. J.R. Secker, J.A. Brown, Westinghouse PWR burnable absorber evolution and usage, Trans. Am. Nucl. Soc. 103 (2010) 733-734.
  21. F.B. Sweidan, R.H. J, Composite Material Properties Simulation for the Fuel Performance Evaluation of Gadolinia-cored UO2 Fuel, Transaction of the Korean Nuclear Society Autumn Meeting, Gyeongju, Korea, 2017. October 25-27.
  22. Q. Mistarihi, F.B.R.H.J. Sweidan, Thermo-physical properties of bulk Gd2O3 for fuel performance analysis of a lumped burnable absorber fuel design, in: Transactions of the Korean Nuclear Society Autumn Meeting, Gyeongju, Korea, October 25-27, 2017.
  23. Q. Mistahiri, M.S. Yahya, H.J. Ryu, Fabrication process of neutron absorber inserted oxide fuel pellet, in: 12th Pacific Rim Conference on Ceramic and Glass Technology (PACRIM 12), Including Glass & Optical Materials Division Meeting (GOMD 2017), Hawaii, USA, May 21-26, 2017.
  24. X.H. Nguyen, A.A. E, Y. Kim, Optimization of centrally shielded burnable absorbers in soluble-boron-free SMR design, in: Transactions of the Korean Nuclear Society Autumn Meeting, Gyeongju, Korea, 2017.
  25. X.H. Nguyen, A. Rahman, Y. Kim, Concepts and Characteristics of a Soluble-Boron-free SMR with Centrally-shielded Burnable Absorber, PHYSOR 2018, Cancun, Mexico, 2018.