The kinetics of the zirconium'UOn reaction was studied using crystal-bar zirconium and fused UOn or UOn high'fired in hydrogen. The reaction was studied with (1) solid zirconium cylinders and UOy powder, (2) compacted mixtures of zirconium and UOn powders, and (3) sandwich' type elements. Experiments performed with sandwich-type elements yielded the most useful data both from a practical and a fundamental point of view. Exploratory experiments designed to give a wider range of experimental materials were unsuccessful in producing substoichiometric UO^. Results obtained from sandwich-type experiments showed that slow reactions at PSO and 1100 F formed reaction zones less than 0.0002 in, thick in 65 days, A measurable reaction took place at 1300 F, while at 2000 F, the reaction was very rapid. The UOn seems to be reduced to its elements, uranium and oxygen, which diffuse simultaneously, but not with equal speed, into the zirconium. Reactants heated at 1300 c and slowly cooled to room temperature, were found to have formed alpha zirconium and alpha uranium adjacent to the UOn, Deeper in the original zirconium region the epsilon uraniumzirconium intermetallic phase was found dispersed in a zirconium-oxygen solid solution. Elements slowly cooled from 2000 F contained alpha zirconium and alpha uranium at the UOn-metal interface. A continuous stained band having the alpha uranium lattice structure and containing some zirconium was observed beneath the two-phase region. Oxygen had diffused beyond the uranium-containing region, forming the hard zirconium-oxygen solid solution. On the basis of limited data obtained, it has been estimated that penetration of oxygen through the 0.030-in.-thick zirconium jacket walls probably would cause their destructive embrittlement in about 300 days at 1300'*F or 2-1/2 days at 2000^. The reaction between Zircaloy 2 and UOn at 1300 F appears to be somewhat less rapid than that between unalloyed zirconium and UOn. The phases formed by this reaction have not been identified.

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This study was undertaken to develop a more practical mercury cathode for use in analytical separations. A new mercury cathode has been designed which employs a magnetic circuit.The cathode removes metals rapidly and completely, is rugged and convenient to operate, and contains no mechanical moving parts. The novel magnetic circuit provides rapid countercurrent stirring at the mercury electrolyte interface, continuously cleans mercury surface (ferromagnetic element), and requires a minimum amount of mercury per analysis. Electrolysis with the mercury cathode is often used as a means of separation of certain elements in analytical techniques. It is particularly useful where large amounts of interfering metals must be separated from small quantities of other elements to be assayed. The new cathode provides the analytical chemist with a practical, rapid tool for quantitative analytical separations.

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