Title: SEMI-ANNUAL PROGRESS REPORT FOR THE PERIOD JANUARY 1960 THROUGH JUNE 1960

Modifications were made in the Carlson and Banks procedure for the spectrophotometric determination of silicon in beryllium metal and oxide. The refractory oxide is dissolved directly in hydrofluoric acid. The identical procedure is used for metal after ignition to the oxide. Concentrations of beryllium over certain limits have a quenching effect on the fluorescence of the aluminum-Portachrome Blue Black R complex. The determination of trace amounts of aluminum in beryilium can be carried out despite this quenching effect by the method of standard addition. Samples of plutonium sulfate tetrahydrate prepared 9 to 12 months earlier were under investigation to determine the suitability of this compound as a primary analytical standard of plutonium. The compound was determined experimentally to contain four molecules of water of crystallization. Plutonium sulfate tetrahydrate was found to lose a major portion of its water of crystallization when heated at 115 ts C. Indications, but no conclusive evidence, of the existence of another intermediate hydrate of plutonium(IV) sulfate, were found. Microscopic examination of 1-year-old crystals of Pu(S0/sub 4/)/sub 2/.4H/sub 2/0 shows no evidence of the effect of any alpha radiolysis on the water of crystallization. Continued exposure to a fluctuating atmosphere caused no apparent changes in crystal structure or weight. Heating Pu(SO/sub 4/)/sub 2/.4H/sub 2/0 to 325 ts C produced a dehydrated salt of weight equivalent to the formula, Pu(S0/sub 4/)/sub 2/. This material, although slightly hygroscopic, can be readily dried at 120 ts C and appears to be satisfactory for further investigation of its suitability as an alternate primary stand ard of plutonium. A method is presented for the rapid determination of milligram quantities of sulfateiIn pure plutonium sulfates. Plutonium is adsorbed on a cation resin and an acidimetric titration is made of the displaced hydrogen ion which is equivalent to the sulfate content of the sample. A technique used for the prevention of plutonium hydrolysis in neutral solution is described. The method may be applied to the determination of sulfate in any pure plutonium sulfate. A method is described for sampling and analyzing uranium in graphite waste. Sampling data indicate that representative sampling is obtained if the material is pulverized to less than 30-mesh size before reducing to 20 to 50-g portions for analysis. A HN0/sub 3/ (l - 3) digestion is sufficient for extracting the total uranium in the waste material. Details for the preparation of synthetic scrap solutions of uraniumaluminum, uranium- stainless steel, and uranium-Zircaloy-2 are presented. Methods of analysis are described and precision data given for the determination of uranium in these solutions. Further evaluation of the isotopic abundance of uranium by mass spectrometric determination was made, and comparisons are shown for National Bureau of Standards and New Brunswick Laboratory values of standard sample NBS-U- 200. (auth)