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 ›› 2019, Vol. 30 ›› Issue (1): 1 doi: 10.1007/s41365-018-0540-8

• NUCLEAR ENERGY SCIENCE AND ENGINEERING •     Next Articles

Avoiding sealing failure of flanged connection for tubes made of dissimilar materials subjected to elevated temperature

Qi-Ming Li, Chong Zhou, Jian Tian, Yao Fu, Yang Zou, Na-Xiu Wang   

  1. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
  • Received:2018-04-03 Revised:2018-06-29 Accepted:2018-08-10
  • Contact: Qi-Ming Li E-mail:liqiming@sinap.ac.cn
  • Supported by:
    This work was supported by the Chinese TMSR Strategic Pioneer Science and Technology Project (No. XDA02010000) and the Frontier Science Key Program of Chinese Academy of Sciences (No. QYZDY-SSW-JSC016).
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Qi-Ming Li, Chong Zhou, Jian Tian, Yao Fu, Yang Zou, Na-Xiu Wang. Avoiding sealing failure of flanged connection for tubes made of dissimilar materials subjected to elevated temperature.Nuclear Science and Techniques, 2019, 30(1): 1     doi: 10.1007/s41365-018-0540-8
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Abstract: Carbonic composite materials and ceramics appear to be excellent structural materials for parts subjected to very high temperatures in molten salt reactors (MSRs), in which the reactor core outlet temperature is normally above 700 °C. Because of the high temperature, there are major challenges in the sealing of flanged connections for tubes made of alloys and nonmetallic materials. In this study, an improved method for sealing bolted flange connections for tubes made of dissimilar materials at high temperature is analyzed. The study focuses on the compensation mechanism for the difference in thermal expansion between the bolts and the flanges. An angle is introduced for the sealing surface in the flanged connection to provide effective sealing. The arctangent of the angle is the ratio of the thickness between the theoretical core of the sealing surface and the outside end face of the flange to the distances between the axis of the flanged joint and the theoretical core of the sealing surface of the flange; the sealing surface of the flange, which is made of the same material as the fastening assemblies, faces the fastening assemblies. To ensure effective sealing, the frictional coefficient between the two sealing surfaces should not exceed the tangent of the angle. This result does not agree well with the solution given by previous researchers. Further, in the modified flanged connection, the compression of each bolt in the clamped condition is increased to maintain the compaction force unchanged without increasing the number of bolts on the flanged joint.

Key words: Sealing, Composite flanged connections, Thermal expansion, Mechanical analysis, Molten salt reactors