Dynamic characteristics of a perforated cylindrical shell for flow distribution in SMART

Seungho Lim, Youngin Choi, Kyungrok Ha, Kyoung Su Park, No Cheol Park, Young Pil Park, Kyeong Hoon Jeong, Jin Seok Park

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


The System-integrated Modular Advanced ReacTor (SMART) is a small nuclear reactor under development in Korea. It is equipped with a perforated cylindrical shell, which is called a flow skirt, in the lower plenum of the reactor for uniform flow distribution and to prevent inflow of debris into the core. This perforated cylindrical shell can be excited by external forces such as seismic or pump pulsation loads. The dynamic characteristics of the perforated cylindrical shell must be identified for further dynamic analysis. This research explores the modal analysis of the scaled-down flow skirt model submerged in coolant water. For the numerical simulation, finite element analysis is carried out to extract modal characteristics of the structure considering the fluid-structure interaction and we introduce the NAVMI factor for similarity analysis. In the finite element model, the whole shape of the perforated cylindrical shell is simulated instead of using the effective material properties. In addition, a 1/12 scaled-down flow skirt is manufactured, and an experiment is designed using an exciter and waterproof accelerometers for the modal test. Due to excellent agreement between the modal test results and the finite element analysis results such as natural frequencies and mode shapes, the finite element model is validated and can be used to predict the dynamic characteristics of the real flow skirt. Moreover, the natural frequency of the real flow skirt can be calculated from the NAVMI factor and is in good agreement with the FEM result.

Original languageEnglish
Pages (from-to)4079-4088
Number of pages10
JournalNuclear Engineering and Design
Issue number10
Publication statusPublished - 2011 Oct

Bibliographical note

Funding Information:
The support of the Korea Atomic Energy Research Institute (KAERI), which has designated this research as a specialization project by Yonsei University, is gratefully acknowledged. Acknowledgement is also given to the ‘Technology Verification and Acquisition of Standard Design Approval of SMART’ project.

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering
  • Materials Science(all)
  • Safety, Risk, Reliability and Quality
  • Waste Management and Disposal
  • Mechanical Engineering


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