Two coextruded, Zr-2 clad, natural uranium, seven rod cluster fuel elements were irradiated to a calculated exposure of 1250 MWD/T in the KER Facility and discharged 1-16-59. The fuel elements were NPR candidate fuel and examination was requested to determine the behavior of coextruded, Zr-2 clad, natural uranium irradiated at core temperatures of approximtely 425{degree}C. The elements were transferred to the Radiometallurgy Laboratory 2-25-59. The elements demonstrated excellent in reactor performance with no significant changes in either the fuel or the hardware. Detailed examination of the central rod and two peripheral rods from one of the clusters showed no microcracks in the uranium. Moderate growth was observed in the fuel at the unrestricted rod ends.

The objective of this Supplement described in this report to Pt-IP-250-A is to d enriched tube-and-tube elements will develop pitting corrosion on the Zircaloy-2 jackets when irradiated in pH 10 water. The measurement of dimensional changes in the fuel elements and the observation of the effect of irradiation on the uranium and bond area are also objectives of the test, but secondary in importance to identifying a pitting corrosion problem in NPR quality water, if one exists.

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for filtration of plutonium oxalate slurries. A scalpel produces a slit in the filter precoat, leading to increased filtration in this slit, and the oxalate is removed by a doctor knife; this technique results in prolonged blowback cycles and more uniform delivery of filtered oxalate to subsequent processing steps. Several types of filter media were tested, and rigid porous aluminum oxide was found to be the best one. (D.L.C.)

The objectives of this study were to demonstrate that the pump speed control system will respond as defined in the equipment specifications and to determine optimum values of controlling variables that will minimize the oscillations that occur in the Na flow rate when transient signals are imposed on the pump speed control system. (W.L.H.)

The failure of defected Zircaloy-2-clad uranium and uranium -2 wt.% zircorium fuel specimens in high-purity high-pressure water at 200 to 345 deg C was observed in a windowed antcclave. Time-lapse color motion pictures were taken to provide a record of the progressive changes ending in the complete disintegration of the core material in the specimens. Continuous measurement of the pressure increase caused by accumulation of hydrogen served to monitor the progress of the reaction when clouding of the water by corrosion products made visual observation impossible. The nature of the attack of all specimens was similar, although the time at which different stages occurred varied. Following an induction period, the first evidence of attack was the slow formation of a blister in the cladding area surrounding the defect. Eventually, a copions evolution of hydrogen occurried at the base of the swollen area. In general, a crack could be seen in the cladding at this stage. Catastrophic failure of the specimen followed swiftly. The time required for each phase of the reaction was reduced as the temperature was raised. Initial swelling occurred after about 24 min at 345 deg C but only after 8 hr at 200 deg C. Diffusion-treated uranium2 …