Fluid storage device comprising a hull and a sealed thermally insulating tank arranged in the hull (4, 5); the tank comprising an interior space intended to store fluid and comprising a tank roof having: - a thermally insulating barrier resting against the hull (4, 5); and - a sealing membrane intended to be in contact with the fluid contained in the tank; the fluid storage device having a gas dome structure (1, 101, 301) comprising: - a sealed pipe (10, 110, 310) having an upper longitudinal end (14, 114, 314) equipped with a connecting flange (18, 118, 318) and a lower longitudinal end passing through the thermally insulating barrier and the sealing membrane of the tank roof so as to define a channel for circulation between the interior space of the tank and at least one vapour collector arranged outside the tank; - a cover (19, 119, 319) that is fixed to said connecting flange (18, 118, 318) by fasteners to close the upper longitudinal end (14, 114, 314) of the sealed pipe (10, 110, 310); - a gasket that is compressed between the cover (19, 119, 319) and the connecting flange (18, 118, 318); - a vapour collecting pipe (3, 17, 117) that passes hermetically through a wall of the sealed pipe (10, 110, 310) so as to enter the sealed pipe (10, 110, 310) in a collecting zone (25, 125, 325), said vapour collecting pipe (3, 17, 117) thus being able to convey vapour between the collecting zone (25, 125, 325) and the vapour collector arranged outside the tank; - the sealed pipe (10, 110, 310) comprising a carrier plate (29, 129, 329) that extends transversely towards the interior of the sealed pipe (10, 110, 310), and is located longitudinally between the collecting zone (25, 125, 325) and the upper longitudinal end (14, 114, 314) of the sealed pipe (10, 110, 310); the carrier plate (29, 129, 329) delimiting, on the one hand, a lower portion of the interior of the sealed pipe (10, 110, 310) that is located below the carrier plate (29, 129, 329) and, on the other hand, an upper portion of the interior of the sealed pipe (10, 110, 310) that is located above the carrier plate (29, 129, 329); - an insulating plug (30, 130, 330) that seals the upper portion of the interior of the sealed pipe (10, 110, 310), said insulating plug (30, 130, 330) comprising an upper surface and a lower surface, which are opposite the cover (19, 119, 319) and the carrier plate (29, 129, 329), respectively; the carrier plate (29, 129, 329) supporting the insulating plug (30, 130, 330) and interacting with the lower surface of the insulating plug (30, 130, 330) on the entire periphery of said lower surface so as to form a barrier limiting a thermal convection effect between the lower portion and the upper portion of the interior of the sealed pipe (10, 110, 310). - a thermally insulating barrier resting against the hull (4, 5); and - a sealing membrane intended to be in contact with the fluid contained in the tank; the fluid storage device having a gas dome structure (1, 101, 301) comprising: - a sealed pipe (10, 110, 310) having an upper longitudinal end (14, 114, 314) equipped with a connecting flange (18, 118, 318) and a lower longitudinal end passing through the thermally insulating barrier and the sealing membrane of the tank roof so as to define a channel for circulation between the interior space of the tank and at least one vapour collector arranged outside the tank; - a cover (19, 119, 319) that is fixed to said connecting flange (18, 118, 318) by fasteners to close the upper longitudinal end (14, 114, 314) of the sealed pipe (10, 110, 310); - a gasket that is compressed between the cover (19, 119, 319) and the connecting flange (18, 118, 318); - a vapour collecting pipe (3, 17, 117) that passes hermetically through a wall of the sealed pipe (10, 110, 310) so as to enter the sealed pipe (10, 110, 310) in a collecting zone (25, 125, 325), said vapour collecting pipe (3, 17, 117) thus being able to convey vapour between the collecting zone (25, 125, 325) and the vapour collector arranged outside the tank; - the sealed pipe (10, 110, 310) comprising a carrier plate (29, 129, 329) that extends transversely towards the interior of the sealed pipe (10, 110, 310), and is located longitudinally between the collecting zone (25, 125, 325) and the upper longitudinal end (14, 114, 314) of the sealed pipe (10, 110, 310); the carrier plate (29, 129, 329) delimiting, on the one hand, a lower portion of the interior of the sealed pipe (10, 110, 310) that is located below the carrier plate (29, 129, 329) and, on the other hand, an upper portion of the interior of the sealed pipe (10, 110, 310) that is located above the carrier plate (29, 129, 329); - an insulating plug (30, 130, 330) that seals the upper portion of the interior of the sealed pipe (10, 110, 310), said insulating plug (30, 130, 330) comprising an upper surface and a lower surface, which are opposite the cover (19, 119, 319) and the carrier plate (29, 129, 329), respectively;