Abstract: The invention concerns a safety cooling installation for the water reactor of a nuclear power station, the installation notably incorporating a reservoir for storing a cooling liquid, the said reservoir being located outside the containment which encloses the reactor circuit, the installation being provided with aspiration and discharging means arranged to aspirate the liquid from the reservoir and to discharge it into the circuit, there being provided a passive, maintenance free means to recover and conduct the liquid and containment water, the said means being arranged to recover the liquid and the water from the reactor in the lower part of the containment by non gravitational flow in the event of a break in the reactor's circuit.