Chemical Engineering Division Summary Report for October, November, December 1959

Chemical-Metallurgical Processing. A direct-cycle pyrometallurgical fuel-processing plant is being constructed in conjunction with EBR-II. The gamma- irradiation testing of the 175-watt white fluorescent mercury vapor lamp was continued to an integrated exposure of 2 x 10/sup 9/ rad. Irradiation tests of Shell APL grease were completed, and the estimated useful life of this grease in the Air and Argon Cells is 2 and 3 years, respectively. Tests of the three - types of d-c motors used in the operating manipulator of the Argon Cell indicate an expected useful cell operating life of 2 to 3 years. Continued irradiation tests of mineralinsulated cable show no catastrophic breakdown of the electric insulation even after an accumulated gamma dose of 8.4 x 10/sup 9/ rad. The scheme currently under consideration for processing melt-refining residues involves a reduction of skull oxides by a solution of Mg in liquid Cd. Molten salt fluxes had variable effects on the rate of oxide reduction in dilute Mg systems. Work was continued on development of processes for EBR-II blanket materials. A large-scale metal-distillation unit to demonstrate metal distillation at rates up to 100 kg/hour is under construction. Two medium carbon steel thermal-convection loops were built and operated to ascertain the extent of corrosion under adverse thermal conditions. Data were obtained for the solubilities of V, Fe, and Ni in liquid Cd at temperatures from 400 to 650 deg C. Corrections were made to data on the solubility of Th in liquid Zn. Solubilities of U in Si-free Zn--Mg solutions were found to be significantly higher than when silicon was present. The peritectic temperature in the U--Cd system was found to be 474 plus or minus l deg C. The activity coefficient of U in Al at4.8% U and 686 deg C is estimated to be 1.25 x 10/sup -3/, based on a distribution coefficient of U between Cd and Al and the activity coefficient of U in pure Cd. The free energy of formation of UPb/sub 6/, determined by galvanic cell measurements, varied between --14.8 to --10.0 kcal/mole at temperatures of 400 to 800 deg C. Oxygen and fluorine bomb calorimetry are being used to obtaan heats of combustion and heats of formation for sulfur and fluorine compounds of such elements as Mo, W, B, and Zr. Fuel Cycle Applications of Volatility and Fluidization Techniques. Several schemes involving the volatility of UF/sub 6/ were proposed for processing irradiated fuels. These include a direct fluorination process, the Aqueous Dissolution Fluorination (ADF) Process and the Fused Fluoride Volatility Process. The Direct Fluorination Process involves direct fluorination of oxide-matrix fuels with fluorine or other fluorination agents to produce volatile UF/sub 6/ and PuF/sub 6/. Additional studies were made in the Fused Salt Fluoride Volatility Process for the recovery of U from U-- Zr--matrix fuels. Additionsl studies of a one-step fluid-bed process for the conversion of UF/sub 6/ to UO/sub 2/ were made in the newly installed 3-inch Monel reactor. Reactor Safety. The program to clarify the factors governing the pyrophoric characteristics of the metals U, Zr, Th, and Pu was continued with studies of ignition phenomena and the combustion process. Reactor Chemisty. The determination of cross sections of U/sup 236/ with neutrons from the Van de Graaff is reported. A twostep alkaline-permanganate procedure was developed for room-temperature decontamination of stainless steel surfaces. Transportation of decontamination reagents using foaming techniques is being investigated. (For preceding period see ANL-6068.) (W.L.H.)