To prevent a flange coupling portion used at a low temperature from suffering from deterioration of hermeticity due to thermal contraction.
In a fastening structure, a first flange 11 and a second flange 12a are superposed to be fastened with a bolt B and a nut N. The fastening structure is employed at a temperature lower than the atmospheric temperature at which fastening work is carried out. When taking the thickness of the first flange 11 as L1, the thickness of the second flange 12a as L2, the superposed thickness of the first flange 11 and the second flange 12a as L, the coefficient of linear expansion of the first flange 11 as α1, the coefficient of linear expansion of the second flange 12a as α2, and the coefficient of linear expansion of the bolt B as α; the structure satisfies the relation of L×α≥L1×α1+ L2×α2. The quantity of the thermal contraction of the bolt B is not less than the total quantity of the thermal contraction of the first flange 11 and the second flange 12a.
MASUDA TAKAHITO
TAKAHASHI YOSHIHISA
HONJO SHOICHI
SHIMODATE MASATO
ETO KEISUKE
TOKYO ELECTRIC POWER CO
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