The processing of irradiated fuels from power and propulsion reactors is planned by Hanford Atomic Products Operation as part of the Atomic Energy Commission's interim reprocessing scheme. The several chemical processes proposed for the reprocessing of these fuels may be divided into two categories: first, total dissolution processes which dissolve both fuel element cladding and core material and, second, selective dissolution processes which dissolve either cladding or core material. The Niflex process uses a nitric and hydrofluoric acid solution for the total dissolution of stainless steel clad uranium fuel elements.

During the period when the writer mixing fuel element was being evaluated, a small Litton glass lathe and a General Electric Fillerarc welder were used to weld the mixing spool to the fuel element. Due to the condition of these units and to the numerous difficulties encountered with them, it was deemed necessary to design and procure a semi automatic welding unit which could weld in excess of three hundred fuel elements per day.

A knowledge of the surface tension of metals is a valuable tool in many aspects of physical metallurgy. Surface tension is a prime factor in such phenomena as swelling, nucleation and growth, and corrosion by liquid metals, and is also of importance in brazing. casting, and sintering. This survey was initiated to facilitate the selection of an experimental technique for determining the surface tension of uranium in support of current swelling studies of irradiated uranium. It is believed that swelling in uranium in support of current swelling; studies of small bubbles of fission gases (krypton and xenon), and the forces resisting the expansion of these bubbles are the elastic and plastic flow energies and surface tension of the metal. Experimental techniques for the determination of surface tension of solids are still in the development stage, but three techniques appear to be most feasible. These methods are: (1) the mechanical method, in which a tensile lead is used to counterbalance the contractile force of surface tension; (2) the thermal etching method, involving measurement of the dihedral angle at the root of etched grain boundaries; and (3) the electron diffraction method, which analyzes surface tension by the amount of lattice distortion it …