Dynamic characteristics assessment of reactor vessel internals with fluid-structure interaction

  • Received : 2017.03.10
  • Accepted : 2017.05.24
  • Published : 2017.10.25


Improvement of numerical analysis methods has been required to solve complicated phenomena that occur in nuclear facilities. Particularly, fluid-structure interaction (FSI) behavior should be resolved for accurate design and evaluation of complex reactor vessel internals (RVIs) submerged in coolant. In this study, the FSI effect on dynamic characteristics of RVIs in a typical 1,000 MWe nuclear power plant was investigated. Modal analyses of an integrated assembly were conducted by employing the fluid-structure (F-S) model as well as the traditional added-mass model. Subsequently, structural analyses were carried out using design response spectra combined with modal analysis data. Analysis results from the F-S model led to reductions of both frequency and Tresca stress compared to those values obtained using the added-mass model. Validation of the analysis method with the FSI model was also performed, from which the interface between the upper guide structure plate and the core shroud assembly lug was defined as the critical location of the typical RVIs, while all the relevant stress intensities satisfied the acceptance criteria.


Supported by : Korea Institute of Energy Technology Evaluation and Planning (KETEP)


  1. M.J. Jhung, Y.H. Ryu, Study on dynamic response of mechanical component to earthquake, J. Nucl. Sci. Technol. 47 (2010) 1065-1074.
  2. J.B. Park, Y.C. Choi, S.J. Lee, N.C. Park, K.S. Park, Y.P. Park, C.I. Park, Modal characteristic analysis of the APR 1400 nuclear reactor internals for seismic analysis, Nucl. Eng. Technol. 46 (2014) 689-698.
  3. J.F. Sigrist, D. Broc, C. Laine, Dynamic analysis of a nuclear reactor with fluid-structure interaction Part I: seismic loading, fluid added mass and added stiffness effects, Nucl. Eng. Des. 236 (2006) 2431-2443.
  4. Y.C. Choi, S.H. Lim, B.H. Ko, K.S. Park, Y.P. Park, K.H. Jeong, J.S. Park, Dynamic characteristics identification of reactor internals in SMART considering fluid-structure interaction, Nucl. Eng. Des. 255 (2013) 202-211.
  5. M.J. Jhung, Y.B. Kim, A study on modal characteristics of flow skirt using effective Young's modulus, Nucl. Eng. Technol. 44 (2012) 501-506.
  6. M.J. Jhung, S.O. Yu, Y.T. Lim, Dynamic characteristics of a partially fluid-filled cylindrical shell, Nuclear Engineering and Technology 43 (2) (2011) 167-174.
  7. M.J. Jhung, K.H. Jeong, Free vibration analysis of perforated plate with square penetration pattern using equivalent material properties, Nucl. Eng. Technol. 47 (2015) 500-511.
  8. S.H. Lim, Y.C. Choi, K.R. Ha, K.S. Park, N.C. Park, Y.P. Park, K.H. Jeong, J.S. Park, Dynamic characteristics of a perforated cylindrical shell for flow distribution in SMART, Nucl. Eng. Des. 241 (2011) 4079-4088.
  9. S.U. Han, D.G. Ann, M.G. Lee, K.H. Lee, S.H. Han, Structural safety analysis based on seismic service conditions for butterfly valves in a nuclear power plant, Sci. World J. 2014 (2014) 1-9.
  10. M.J. Jhung, W.G. Hwang, Seismic response of reactor vessel internals for Korean standard nuclear power plant, Nucl. Eng. Des. 165 (1996) 57-66.
  11. C. De, Y.Z. Qiang, X. Yabo, S. Hong, Numerical study on seismic response of the reactor coolant pump in advanced passive pressurized water reactor, Nucl. Eng. Des. 278 (2014) 39-49.
  12. J.J. Bommer, M. Papaspiliou, W. Price, Earthquake response spectra for seismic design of nuclear power plants in the UK, Nucl. Eng. Des. 241 (2011) 968-977.
  13. D.Y. Ko, K.H. Kim, Structural analysis of CSB and LSS for APR1400 RVI CVAP, Nucl. Eng. Des. 261 (2013) 76-84.
  14. M.J. Jhung, Assessment of thermal fatigue in mixing tee by FSI analysis, Nucl. Eng. Technol. 45 (2013) 99-106.
  15. ASME Boiler & Pressure Vessel Code, Section III - Nuclear Power Plant Components; Division 1-Subsection NG, Core Support Structure, American Society of Mechanical Engineers, 2007.
  16. D.H. Kim, Y.S. Chang, M.J. Jhung, Numerical study on fluid flow by hydrodynamic loads in reactor internals, Struct. Eng. Mech. 51 (2014) 1005-1016.
  17. G.C. Everstine, A symmetric potential formulation for fluid-structure interaction, J. Sound Vib. 79 (1981) 157-160.
  18. P. Kohnke, Theory reference for the mechanical APDL and mechanical applications, ANSYS Inc. (2009).
  19. Y.G. Choi, J.B. Park, S.J. Lee, N.C. Park, Y.P. Park, J.S. Kim, W.J. Roh, Model reduction methods for cylindrical structures in reactor internals considering the fluid-structure interaction, J. Nucl. Sci. Technol. 53 (2016) 204-222.
  20. X. Zhou, R. Yu, L. Dong, The Complex-Complete-Quadratic-Combination (CCQC) method for seismic responses of Non-classically Damped Linear MDOF system, in: Proceedings of the 13th World Conference on Earthquake Engineering, Vancouver, Canada, 2004.
  21. U.S. Nuclear Regulatory Commission, Regulatory Guide 1.60, Design response spectra for seismic Design of Nuclear Power Plants, U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research, Washington D.C, 2014.
  22. U.S. Nuclear Regulatory Commission, Regulatory Guide 1.61, Damping Values for seismic Design of Nuclear Power Plants, U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research, Washington D.C, 2007.