Gas cooled nuclear reactor system having improved shield and flow path arrangement

Claim 1

IN A GAS COOLED NUCLEAR REACTOR ASSEMBLY, A CONCRETE PRESSURE AND BIOLOGICAL PROTECTION VESSEL HAVING A VERTICAL AXIS, A PRESSURE TIGHT CHAMBER IN SAID VESSEL, AN ANNULAR INTERNAL FLANGE INTEGRAL WITH SAID VESSEL AND PROJECTING RADIALLY INWARD FROM SAID VESSEL INTO SAID CHAMBER, A REACTOR CORE UNIT LOCATED IN AN UPPER PORTION OF SAID CHAMBER ABOVE SAID FLANGE AND PROVIDED WITH VERTICAL CHANNELS RECEIVING NUCLEAR FUEL ELEMENTS, HEAT EXCHANGERS LOCATED IN A LOWER PORTION OF SAID CHAMBER UNDER SAID FLANGE, BIOLOGICAL PROTECTION SHIELD IN SAID UPPER PORTION BETWEEN SAID CORE AND SAID HEAT EXCHANGERS INCLUDING A GAS IMPERVIOUS BASE PLATE AND NEUTRON-ABSORBENT MATERIAL, MEANS FOR TRANSFERRING THE WEIGHT OF SAID CORE TO SAID PLATE, MEANS BETWEEN SAID PLATE AND SAID FLANGE FOR TRANSFERRING THE WEIGHT OF SAID PLATE TO SAID FLANGE AND A NEUTRON-ABSORBENT SHIELD ELEMENT DISPOSED BENEATH SAID PLATE ADJACENT TO SAID FLANGE, SAID PLATE HAVING A SMALLER DIAMETER THAN THAT OF THE ADJACENT WALL OF SAID PRESSURE VESSEL PROVIDING PASSAGES BETWEEN THE PERIPHERY OF SAID PLATE AND SAID PRESSURE VESSEL FOR COLD GAS TO SAID REACTOR CORE AND FOR HOT GAS FROM SAID CORE TO SAID EXCHANGERS, SAID PLATE AND SAID SHIELD ELEMENT PREVENTING DIRECT NEUTRON STREAMING FROM SAID CORE TO SAID HEAT EXCHANGERS.