Fluid-storage facility

The invention relates to a fluid storage facility, the storage facility comprising a supporting structure (1) and a tank, the tank having at least one tank bottom wall fixed to the supporting structure (1), wherein the bottom wall has a structure with multiple layers superimposed in a direction of thickness, including at least one sealing membrane and at least one thermal insulation barrier arranged between the sealing membrane and the supporting structure (1),wherein the bottom wall has a sump structure (9) having a rigid container (10, 11) comprising a side wall (12), the container (10, 11) being arranged through the thickness of the bottom wall, and the sump structure (9) comprising at least one fixing means (15) designed to fix the rigid container (11) to the supporting structure (1) at a fixing point,and wherein the at least one fixing means (15) is configured to allow the relative movement of the side wall (12) of the container (11) with respect to the supporting structure (1) in a transverse direction perpendicular to the side wall (12) at the fixing point of the container (11).