Abstract: The invention relates to floating roof tanks for liquids, of the type comprising a cylindrical wall (2), a floating roof (3), and a flexible membrane (4) connecting the periphery of the floating roof to the wall. In accordance with the invention, the tank further includes an overflow duct for providing protection against over-filling when the roof (3) is in its top position. The overflow duct (26) is mounted on the outside of the tank and has an upsidedown U-shaped portion disposed at a height corresponding to a maximum predetermined level for liquid inside the tank when the roof is in its top position. The invention is applicable to the nuclear power industry for storage tanks for topping up the primary circuit of a nuclear reactor with de-gassed water.

Abstract: The invention relates to floating roof tanks for liquids, of the type comprising a cylindrical wall (2), a floating roof (3), and a flexible membrane (4) connecting the periphery of the floating roof to the wall. In accordance with the invention, means are provided for emptying the counter-pressure liquid which is located in the space (6) delimited by the membrane (4) and the wall (2) and which is open to the atmosphere. These emptying means are disposed near the top of the tank so that the membrane, under the effect of pressure exerted by the liquid contained in the tank, serves to expel the counter-pressure liquid when the roof is in abutment against a top stop. Such tanks are of particular use in the nuclear power industry for storing de-gased water to top up the primary circuit of a nuclear reactor.