Fuel tube element and method of preparing the same

Claim 1

THAT IMPROVEMENT IN THE PROCESS OF PREPARING CLAD NUCLEAR REACTOR FUEL ELEMENTS OF TUBULAR TYPE COMPRISING THE STEPS OF PROVIDING A MANDREL, TREATING THE SURFACE OF THE LATTER TO PREVENT BONDING THEREON OF COMPONENTS OF THE ELEMENT, MOUNTING A FIRST ALUMINUM TUBE ON THE MANDREL, SWAGING A TIP OF SAID FIRST TUBE TO THE MANDREL, COLD DRAWING SAID FIRST TUBE ON SAID MANDREL TO IMPART A SELECTED THICKNESS THERETO AND TO CONFORM ITS INNER SURFACE TO THE SURFACE OF THE MANDREL, CHEMICALLY CLEANING THE SAID FIRST TUBE, MOUNTING A TUBULAR CORE OF A CERMET CONTAINING ALUMINUM AND URANIUM DIOXIDE OVER THE COLD DRAWN FIRST TUBE, MOUNTING A SECOND ALUMINUM TUBE OVER THE SO POSITIONED CORE, SWAGING A TIP OF THE SECOND ALUMINUM TUBE TO THE MANDREL, MOUNTING A PROTECTIVE TUBE OVER SAID SECOND TUBE, SWAGING A TIP OF SAID PROTECTIVE TUBE TO THE MANDREL AND SEALING IT IN LEAKPROOF MANNER TO THE MANDREL, ELEVATING THE TEMPERATURE OF THE ASSEMBLED COMPONENTS AND OF A DRAWING DIE, APPLYING A VACUUM TO THE ASSEMBLED COMPONENTS AND WHILE MAINTAINING SAID VACUUM AND THE ELEVATED TEMPERATURE, HOT DRAWING THE COMPONENT ASSEMBLY THROUGH THE HEATED DIE TO EFFECT METALLURGICAL BONDING OF THE ADJOINING SURFACES BETWEEN THE FIRST AND SECOND TUBES AND THE CORE, AND THEREAFTER REMOVING THE PROTECTIVE TUBE.