Fuel element

Claim 1

A NUCLEAR REACTOR FUEL ELEMENT COMPRISING A BLOCK OR REFRACTORY MATERIAL HAVING RELATIVELY GOOD THERMAL CONDUCTIVTY AND NEUTRON MODERATING CHARACTERISTICS WHICH BLOCK HAS A PAIR OF PARALLEL FLAT END FACES AND A PLURALITY OF SIDES WHICH ARE SUBSTANTIALLY PERPENDICULAR TO SAID END FACES, SAID SIDES BEING SO ARRANGED THAT THE CROSS SECTION OF SAID BLOCK TAKEN PARALLEL TO SAID END FACES IS A POLYGON OF PREDETERMINED SHAPE, SAID SHAPE BEING SUCH THAT A PLURALITY OF SAID BLOCKS CAN BE INTERFITTED TOGETHER SIDE-BY-SIDE TO PROVIDE A SUBSTANTIALLY CONTINUOUS CORE ARRAY, SAID BLOCK CONTAINING A PLURALITY OF COOLANT HOLES WHICH ARE ARRANGED IN A TRIANGULAR ARRAY AND WHICH EXTEND AXIALLY COMPLETELY THERETHROUGH FROM END FACE TO END FACE, SAID BLOCK ALSO CONTAINING A PLURALITY OF INTEGRALLY FORMED AXIALLY EXTENDING CLOSED FUEL CHAMBERS FOR HOLDING NUCLEAR FUEL MATERIAL, SAID FUEL CHAMBERS BEING ARRANGED IN A TRIANGULAR ARRAY OF LESSER PITCH THAN THE PITCH OF THE COOLANT HOLE ARRAY SO THAT A PLURALITY OF FUEL CHAMBERS SURROUND EACH COOLANT HOLE, SAID COOLANT HOLES BEING OF LARGER DIAMETER THAN SAID FUEL CHAMBERS AND EACH FUEL CHAMBER BEING EQUIDISTANT FROM TWO COOLANT HOLES, AND SAID BLOCK HAVING AT SAID END FACES INTERENGAGING MEANS FOR PRECISELY AXIALLY ALIGNING ONE OF THESE FUEL ELEMENTS WITH ANOTHER OF THESE FUEL ELEMENTS DISPOSED AXIALLY ADJACENT IT, SAID MEANS INCLUDING A PLURALITY OF PINS PROTRUDING FROM ONE END FACE THEREOF AND MATING CAVITIES AT THE OTHER END FACE THEREOF PROPORTIONED TO RECEIVE SAID PINS.