| 摘要 |
PROBLEM TO BE SOLVED: To maintain sealing performance by preventing a crevice corrosion and a damage on the sheet surface of a reactor pressure vessel flange. SOLUTION: This protective device 1 for the sheet surface for protecting the sheet surface 31 of a shell side flange when dismantling an upper mirror of the reactor pressure vessel is equipped with two supports 3, 5 arranged on the sheet surface 31 at an interval of the aperture part length x, a plate 9 for covering the supports 3, 5, and a coupling means 14 for coupling the plate 9 to a stud bolt 35, and also provided with an aperture larger than a correlation value y calculated by the equation: y=0.26logx+0.2, between the under surface of the plate 9 and the sheet surface 31. In addition, the material of the plate 9 is formed from a material having a base metal position in a electrochemical potential series in aqueous solution than the material of sheet surface 31. COPYRIGHT: (C)2004,JPO
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