| 摘要 |
Disclosed is a method for detecting a defect in an LNG tank, in which: a lattice sampling pipe arrangement is provided in a thermal insulation section of a containment system of a membrane system LNG tank constituted by the thermal insulation section and an inter barrier section with a secondary barrier, which is an object to be detected, disposed as a boundary between the thermal insulation section and the inter barrier section, the lattice sampling pipe arrangement having holes formed at predetermined intervals and disposed at lattice points thereof; sampling pipes of the lattice sampling pipe arrangement are connected to a single gas densimeter individually through respective valves; a tracer gas is led into the inter barrier section so that the density of the tracer gas leaking through the object to be detected is measured by the gas densimeter with respective to each of the sampling pipes; total data is prepared by using a processing mechanism on the basis of the result of measurement of density obtained from each of the sampling pipes; and a leakage portion in the object to be detected is identified and detected by estimating the gas density at each of the lattice points on the basis of the total data, |
