Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2020, Vol. 31 ›› Issue (1): 5 doi: 10.1007/s41365-019-0721-0

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Seismic and stress qualification of LMFR fuel rod and simple method for determination of LBE added mass effect

M. Khizer 1,2, Jian-Wei Chen 1, Guo-Wei Yang 1,2, Qing-Sheng Wu 1, Yong Song 1, Yong Zhang 1   

  1. 1Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei 230031, China
    2University of Science and Technology of China, Hefei 230027, China
  • Received:2019-05-30 Revised:2019-11-19 Accepted:2019-11-21
  • Contact: Jian-Wei Chen
  • Supported by:
    This work was supported by the National Key R&D Program of China (No.2018YFB1900601) and National Natural Science Foundation of China (No. 11772086).
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M. Khizer, Jian-Wei Chen, Guo-Wei Yang, Qing-Sheng Wu, Yong Song, Yong Zhang. Seismic and stress qualification of LMFR fuel rod and simple method for determination of LBE added mass effect.Nuclear Science and Techniques, 2020, 31(1): 5     doi: 10.1007/s41365-019-0721-0

Abstract: In this study, two different designs of liquid metal fast reactor (LMFR) fuel rods wire-wrapped and non-wire-wrapped (bare) are compared with respect to different parameters as a means of considering the optimum fuel design. Nuclear seismic rules require that systems and components that are important to safety must be capable of bearing earthquake effects, and that their integrity and functionality should be guaranteed. Mode shapes, natural frequencies, stresses on cladding, and seismic aspects are considered for comparison using ANSYS. Modal analysis is compared in a vacuum and in lead-bismuth eutectic (LBE) using potential flow theory by considering the added mass effect. A simple and accurate approach is suggested for the determination of the LBE added mass effect and is verified by a manually calculated added mass, which further proved the usefulness of potential flow theory for the accurate estimation of the added mass effect. The verification of the hydrodynamic function (τ) over the entire frequency range further validated the finite element method (FEM) modal analysis results. Stresses obtained for fuel rods against different loading combinations revealed that they were within the allowable limits with maximum stress ratios of 0.25 (bare) and 0.74 (wire-wrapped). In order to verify the structural integrity of cladding tubes, stresses along the cladding length were determined during different transients and were also calculated manually for static pressure. The manual calculations could be roughly compared with the ANSYS results and the two showed a close agreement. Contact analysis methodology was selected and the most appropriate analysis options were suggested for establishing contact between the wire and cladding for the wire-wrapped design grid-independence analysis, which proved the accuracy of the results, confirmed the selection of the appropriate procedure, and validated the use of the ANSYS mechanical APDL code for LMFR fuel rod analysis. The results provided detailed insight for the structural design of LMFR fuel rods by considering different structural configurations (i.e., bare and wire-wrapped) in the seismic loading; this not only provides a FEM procedure for LMFR fuel with complex configuration, but also guides the reference design of LMFR fuel rods.

Key words: LMFR, Fuel rod, Added mass, Seismic analysis, Contact analysis