A new method for the determination of O/sub 2/ in metals is described. The sample is dropped into molten Pt in a graphite crucible. The oxide in the sample reacts with C to form CO, which is swept out by a stream of argon at atmospheric pressure. The CO is oxidized to CO/sub 2/, which is condensed in a capillary trap and measured with a capillary manometer. The apparatus is sensitive to 0.3 mu g of O/sub 2/, and routine 50-mg Pu samples give a standard deviation of 7 ppm or 0.35 mu g. Pu samples with added O/sub 2/ gave a standard deviation of 1.5 mu g or 2% of the total oxygen, with no significant bias. The apparatus is simple and rugged permitting replacement of parts without glassblowing. The speed is superior to vacuum fusion methods, most samples requiring only twelve minutes for analysis.

The usual method of removing surface oxide from plutonium metal samples, by electrolytic cleaning in a mixture of ethylene glycol and phosphoric acid, is not satisfactory for preparing samples for oxygen determination. Samples prepared in this way give erratic oxygen values. This report describes a new method of electrolytic cleaning, using a 20 ~ aqueous potassium carbonate solution as the electrolyte. The sample is placed in a rotating tantalum cup which is made the anode. Electrolysis for two minutes at 4.5 volts is usually sufficient. Samples cleaned by the new method give lower and more consistent oxygen results than those prepared in the old way. The new method is also neater and more convenient.

A high-vacuum casting furnace with an internal diameter of 15 inches has been designed, fabricated, and installed at LASL. The furnace was designed to accommodate casting crucibles up to 7 inches OD; however with a larger diameter heating element, casting crucibles up to 9 inches could be accommodated. This report describes the basic features of the furnace and presents engineering drawings of both the furnace and the furnace box.