Patent Number: 
Section: claims

1. A nuclear reactor system comprising:a nuclear reactor including a reactor core comprising fissile material disposed in a reactor pressure vessel;a radiological containment containing the nuclear reactor;a containment compartment containing the radiological containment;a heat sink comprising a chimney configured to develop an upward-flowing draft in response to heated fluid flowing into a lower portion of the chimney, a body of water in thermal communication with a portion of the radiological containment to transfer heat from the radiological containment into the body of water, a heat sink conduit arranged to receive water vapor or steam from the body of water and to discharge the water vapor or steam into the lower portion of the chimney; anda fluid conduit arranged to receive fluid from the containment compartment and to discharge the fluid from the containment compartment into the chimney,wherein there are no penetrations of the portion of the radiological containment that is in thermal communication with the body of water of the heat sink. 2. The nuclear reactor system of claim 1 further comprising:a filter;wherein the fluid conduit includes:a first fluid conduit arranged to receive fluid from the containment compartment and to discharge into an inlet of the filter; anda second fluid conduit arranged to receive fluid from an outlet of the filter and to discharge into the chimney. 3. The nuclear reactor system of claim 2 wherein the filter is capable of removing radioactive materials. 4. The nuclear reactor system of claim 1 wherein the body of water is a covered body of water located inside the containment compartment and disposed on top of the radiological containment to form the thermal communication with the radiological containment to transfer heat from the radiological containment into the body of water. 5. The nuclear reactor system of claim 1 wherein the fluid conduit is arranged to discharge into the chimney at an elevation that is higher than the elevation at which the heat sink conduit discharges into the chimney. 6. The nuclear reactor system of claim 5 wherein there is no blower or pump configured to move fluid through the fluid conduit. 7. The nuclear reactor system of claim 1 wherein there is no blower or pump configured to move fluid through the fluid conduit.