Studies on wear and frictional behavior between fuel rods and grid spacers in sodium

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Kakehi, Isao*; Tani, Saburo*; Fujii, Eiji*; Okano, Hideharu*; Endo, Kinji*; Kawada, Toshiyuki*; Ogata, Keizo*

Kakehi, Isao*; Tani, Saburo*; Fujii, Eiji*; Okano, Hideharu*; Endo, Kinji*; Kawada, Toshiyuki*; Ogata, Keizo*

None

Changes in the reactor power result in relative movements between the fuel rod bundle and grid spacers, due to thermal expansion of fuel rods. Contact load, which is caused by deformation of fuel rods or axial alignment of grid spacers, is set up on the contact surfaces. From this reason, changes in reactor power are the cause of galling between fuel rods and grid spacers. In this work, wear between fuel rods and grid spacers in sodium was evaluated quantitatively under simulated reactor conditions, and a mock-up test in sodium was carried out in order to evaluate designs of the fuel rod, grid spacers, and grid spacer mounting methods.