Fuel elements for nuclear reactors

Claim 1

A CLUSTER FUEL ELEMENT COMPRISING A GRAPHITE TUBULAR CASING FOR CONDUCTING COOLANT, AN ELONGATE FUEL ASSEMBLY DISPOSED LENGTHWISE WITHIN THE CASING, FUEL ASSEMBLY SUPPORT MEANS ADJACENT ONE END OF THE CASING AND ARRANGED TO TRANSMIT THE WEIGHT OF THE FUEL ASSEMBLY TO THE WALL OF THE CASING, SAID FUEL ASSEMBLY COMPRISING FIRST AND SECOND GRID STRUCTURES SPACED APART FROM EACH OTHER AND DISPOSED TRANSVERSELY WITHIN THE CASING WITH THE FIRST GRID STRUCTURE CARRIED BY SAID SUPPORT MEANS, SAID FIRST AND SECOND GRID STRUCTURES DEFINING ALIGNED LATTICES OF OPENINGS, A CLUSTER OF ELONGATE FUEL MEMBERS EXTENDING LENGTHWISE BETWEEN THE GRID STRUCTURES, THE ENDS OF THE FUEL MEMBER BEING IOCATED BY THE OPENINGS OF THE GRID STRUCTURES AND BEING UNITED WITH THE GRID STRUCTURES BY A METALLURGICAL BOND, SAID SECOND GRID STRUCTURE HAVING SIDE CLEARANCE WITH THE WALL OF THE CASING SO AS TO ALLOW LONGITUDINAL MOTION OF THE SECOND GRID STRUCTURE WITHIN THE CASING, THE GRID STRUCTURES COMPRISING THIN WEBS DISPOSED EDGE-ON TO COOLANT FLOW THROUGH THE CASING, THE WEBS BEING DEFORMABLE UNDER AXIAL LOADING RESULTING FROM LONGITUDINAL GROWTH OF THE INDIVIDUAL FUEL MEMBER UNITED THEREWITH AND WITHOUT UNDUE STRESSING OF SAID FUEL MEMBERS, SAID THIN WEBS COMPRISING THIN STRIPS HAVING TRANSVERSE TROUGHS AT INTERVALS AND ASSEMBLED WITH THE LENGTHS OF THE STRIPS INTERMEDIATE THE TROUGHS JUXTAPOSED IN PAIRS TO FORM THE WEB OF THE STRUCTURE, WITH THE TROUGH COMING TOGETHER TO DEFINE OPENINGS FOR END-LOCATION OF THE FUEL MEMBERS, THE JUXTAPOSED LENGTHS OF THE STRIPS BEING SECURED TOGETHER REMOTE FROM THE TROUGHS.