Journal of Mechanical Science and Technology

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지

The Analysis of Flow-Induced Vibration and Design Improvement in KSNP Steam Generators of UCN ＃5, 6

  • Kim, Sang-Nyung (Department of Nuclear Engineering, Kyunghee University) ;
  • Cho, Yeon-Sik (Department of Nuclear Engineering, Kyunghee University)
  • Published : 2004.01.01
Download PDF
⟨ Previous Next ⟩

Abstract

The KSNP Steam Generators (Youngkwang Unit 3 and 4, Ulchin Unit 3 and 4) have a problem of U-tube fretting wear due to Flow Induced Vibration (FIV). In particular, the wear is localized and concentrated in a small area of upper part of U-bend in the Central Cavity region. The region has some conditions susceptible to the FIV, which are high flow velocity, high void fraction, and long unsupported span. Even though the FIV could be occurred by many mechanisms, the main mechanism would be fluid-elastic instability, or turbulent excitation. To remedy the problem, Eggcrate Flow Distribution Plate (EFDP) was installed in the Central Cavity region or Ulchin Unit 5 and 6 steam generators, so that it reduces the flow velocity in the region to a certain level. However, the cause of the FIV and the effectiveness of the EFDP was not thoroughly studied and checked. In this study, therefore the Stability Ratio (SR), which is the ratio of the actual velocity to the critical velocity, was compared between the value before the installation of EFDP and that after. Also the possibility of fluid-elastic instability of KSNP steam generator and the effectiveness of EFDP were checked based on the ATHOS3 code calculation and the Pettigrew's experimental results. The calculated results were plotted in a fluid-elastic instability criteria-diagram (Pettigrew, 1998, Fig. 9). The plotted result showed that KSNP steam generator with EFDP had the margin of Fluid-Elastic Instability by almost 25％.

Keywords

References

  1. Au-Yang, M. K., 1987, 'Development of Stabilizers for Steam Generator Tube Repair,' Journal Nuclear Engineering and Design, Vol. 122, pp. 189-197 https://doi.org/10.1016/0029-5493(87)90272-X
  2. Axiasa, F., 1986, 'Flow Induced Vibration of Steam Generator Tubes,' Electric Power Research Institute Report EPRI NP-4559
  3. Chen, S. S., 1985, 'Flow Induced Vibration of Circular Cylindrical Structures,' Report No. ANL-85-51
  4. Jo, J. C., 1992, 'A Study on the Thermal-hydraulic and Flow-induced Tube Vibration Analysis of Nuclear Steam Generators,' KINS/AR-198
  5. Kim, S. N., 1998, 'Fluid-elastic Vibration in a Rod Bundle,' Ministry of Science and Technology (MOST), Korea
  6. Kim, S. N., 2000, 'Critical Velocity of Fluidelastic Vibration in a Nuclear Fuel Bundle,' KSME International Journal, Vol. 14, pp. 816-822
  7. Kim, S. N. and Sin, C, 2001, 'The Experimental of Flow Induced Vibration in PWR RCCAs,' KSME International Journal, Vol. 15, pp. 291-299
  8. Lee, C. H., 1991, 'Vibration & Structural Analysis of The Tubes & Tube supports,' ABB-CENP
  9. Lee, L. S., 1971, 'Vibration of U-Bend Segments of Heat Exchanger Tubes,' Atomic Energy of Canada Limited, AECL 3735
  10. Pettigrew, M. J. , Taylor, C. E., Fisher, N. J., Yetisir, M. and Smith, B. A. W., 1998, 'Flow-induced Vibration : Recent Findings and Open Questions,' Journal Nuclear Engineering and Design, Vol. 185, pp. 249-276 https://doi.org/10.1016/S0029-5493(98)00238-6
  11. 'Palo Verde Steam Generator Tube Degradation and YGN3 and 4 Steam Generator Design,' ABB-CENP Report
  12. Pettigrew, M. J. and Taylor, C. E., 1994, 'Two-Phase Flow-Induced Vibration,' ASEM, Vol. 116, pp. 233-252
  13. Pettigrew, M. J., Taylor, C. E. and Kim, B. S., 1989, 'Vibration of Tube Bundles in Two-Phase Cross Flow : Part1 Hydrodynamic Mass and Damping,' Journal of Pressure Vessel Technology Trans. of the ASME, Vol. 3, pp. 466-477
  14. Singhal, A. K. and Keeton, L. W., 1990, 'ATHOS3 Mod-01:A Computer Program for Thermal-Hydraulic:Analysis of Steam Generatiors,' EPRI NP-4604-CCML, Vol. 1-3
  15. Singhal, A. K. and Srikantiah, G., 1991, 'A Review of Thermal Hydraulic Analysis Methodology for PWR Steam Generators and ATHOS3 Code Applications,' Progress in Nuclear Energy, Vol. 25, No. 1, pp. 7-70 https://doi.org/10.1016/0149-1970(91)90041-M
  16. Slack, D. G., 2001, 'Vibration and Structural Analysis of the Tubes and Tube supports (UE-211SS-302),' WEC LLC