Abstract: A method for checking the sealing of a sealed tank for storing a liquefied gas at low temperature, the tank having an inner hull and a secondary sealing membrane, a secondary space that is arranged between the inner hull and the secondary sealing membrane, a primary sealing membrane and a primary space that is arranged between the primary sealing membrane and the secondary sealing membrane is disclosed. The method has the following main steps: generating a pressure lower than the pressure of the primary space in the secondary space using a suction device, measuring the temperature of an outer surface of the inner hull, and detecting the location of a sealing defect of the secondary sealing membrane in the form of a cold spot on the outer surface of the inner hull.

Abstract: A method is described for checking the sealing of a sealed and thermally insulating tank for storing a liquefied gas at low temperature. The tank has a primary space and a secondary space where, in order to perform the check, a difference in pressure is created between the two spaces at least some of the inert gas injected into the primary space is recovered via at least one secondary outlet of the secondary space so as to be reinjected into the primary space.

Abstract: A floating structure including a sealed and thermally insulated tank. An upper bearing wall bears a turret-like cargo tank dome intended for the passage of cargo handling equipment. The turret-like cargo tank dome with an internal fluidtight wall forming a sheath engaged through the opening in the upper bearing wall and connected in fluidtight manner to the primary sealing membrane of the upper tank wall all around the sheath. Respective primary and secondary venting devices allow gas to be vented respectively from the primary and secondary spaces of the turret-like cargo tank dome. A gas reservoir containing a tracer gas that is non-condensable or that has a condensation temperature below the low temperature of the liquefied gas contained in the tank is connected via a control valve to one of the venting devices that are the primary venting device and the secondary venting device.