Low temperature liquid tank

A low temperature liquid tank comprising:

• a storage tank having a bottom portion obtained by joining a plurality of bottom plates;
• and
• a support portion supporting the bottom portion,
• wherein the support portion includes:
• an outer support portion supporting a margin of the storage tank including a sidewall of the storage tank;
• and
• an inner support portion disposed inside the outer support portion and having a heat insulation in which creep occurs when a load is applied to the heat insulation,
• an initial height of an upper surface of the inner support portion is set so that, during a service life of the low temperature liquid tank, maximum bending stress applied to the bottom plates due to a difference between a height of the upper surface of the inner support portion and a height of an upper surface of the outer support portion remains equal to or smaller than an allowable bending stress of the bottom plates,
• wherein the initial height of the upper surface of the inner support portion is set to be higher than that of the upper surface of the outer support portion, and
• wherein due to the creep when a load is applied, the upper surface of the inner support portion is lowered during the service life of the low temperature liquid tank, and wherein the initial height of the upper surface of the inner support portion is set so that the maximum bending stress applied to the bottom plates remains equal to or smaller than the allowable bending stress over the service life as the upper surface of the inner support portion is lowered.