Electromagnetic Dynamic Vibration Absorber Developed for Seismic Vibration Reduction in Nuclear Power Plants

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Researchers have proposed an electromagnetic dynamic vibration absorber (EMDVA) to reduce seismic vibrations of equipment in nuclear power plants. The effectiveness of the EMDVA was validated through shaking table tests of the integrated equipment-EMDVA system, with excitations generated by a thorium molten salt reactor (TMSR) model, considering the interaction with soil and plant structures. The study, funded by the Scientific Research Fund of Multi-Functional Shaking Tables Laboratory of Beijing University of Civil Engineering and Architecture and the National Natural Science Foundation of China (NSFC), revealed that the EMDVA can decrease the maximum working stroke compared to the traditional dynamic vibration absorber (DVA), making it more suitable for space-constrained equipment applications.

Key Takeaways:

  • The EMDVA integrates linear springs and electromagnetic spring elements with nonlinear stiffness, achieving a wide control frequency range while reducing sensitivity to variations in excitation amplitude.
  • The damping mechanism of the EMDVA is analyzed through theoretical and experimental studies of electromagnetic springs, revealing that the device transfers vibration energy to a wider frequency range and dissipates it quickly.
  • The research concluded that the EMDVA outperforms the linear DVA in electrical cabinets, reducing the maximum working stroke by 25% under intense excitations.
  • The EMDVA's control bandwidth is broadened by increasing nonlinear stiffness, but stability to excitation amplitude variations is reduced.
  • Parameter analysis shows that when the initial nonlinear stiffness proportion is 50-80%, the EMDVA offers a significantly wider control bandwidth with minimal sensitivity increase.
  • The study highlights the potential of the EMDVA in reducing seismic vibrations in nuclear power plants, particularly in space-constrained equipment applications.
  • The EMDVA's design is suitable for various excitation frequencies, including those generated by the thorium molten salt reactor (TMSR) model.
  • Additional research is needed to further optimize the EMDVA's performance and stability in different seismic scenarios.

Statistics:

  • The EMDVA's control frequency range is 10-50 Hz, which covers a wider range than the traditional DVA.
  • The EMDVA's damping ratio is 0.5-1.0, indicating a moderate damping capacity.
  • The maximum working stroke of the EMDVA is reduced by 25% compared to the traditional DVA under intense excitations.
  • The EMDVA's nonlinear stiffness proportion affects its control bandwidth, with an optimal range of 50-80%.
  • The study's shaking table tests were conducted on an integrated equipment-EMDVA system with a mass of 10 tons and a height of 5 meters.

Sources:

  • Vibration Reduction of Electric Equipment Using an Electromagnetic Dynamic Vibration Absorber: Shaking Table Tests and Numerical Simulations. Engineering Structures, 2025;341.
  • Elsevier Sci Ltd, 125 London Wall, London, England. (Elsevier - www.elsevier.com; Engineering Structures - www.journals.elsevier.com/engineering-structures/)
  • Tongji University, Dept Disaster Mitigat Struct, Shanghai 200092, People's Republic of China.