Coupling of a turbopump for molten salts

A device comprising at least one centrifugal vertical axis pump (3) and at least one associated centrifugal vertical axis turbine (4) for transporting, over a level difference, a heat-transfer fluid brought to a high temperature, the pump (3) ensuring an upward movement of said fluid in a first section of a pipe (17) from a first cold storage reservoir (2) and the turbine (4) being actuated by said fluid during the downward return movement of said fluid in a second section of the pipe (17) toward a second hot storage reservoir (5), wherein the device further comprises a mechanical device for coupling the turbine (4) with the pump (3), said mechanical coupling device comprising a gearbox (21) with a gimbal coupling (41) located on the turbine (4) side, allowing the mechanical energy produced by the turbine (4) to be reused to actuate the pump (3), and wherein the centrifugal turbine (4) is a device substantially identical to the centrifugal pump (3) and has a vertical axis parallel to and of the same orientation as the centrifugal pump (3), but operated for having fluid flowing in the opposite direction.