CHEMICAL ENGINEERING DIVISION SUMMARY REPORT FOR APRIL, MAY, JUNE 1960

7 9 7 D 8 8 9 9 7 7 ; 8 < fuel-reprocessing plant using pyrometallurgical procedures is being designed and constructed as part of the Experimental Breeder Reactor No. 2 project. Cable samples sealed with Temporell No. 741 were irradiated to 3.0 x lO/sup 9/ rad. Tests of the absorber-type fume trap were successful. Preparations were continued for high- activitylevel demonstrations of the melt-refining process for EBR-2 core fuel. An attractive and efficient procedure for removing uranium skull material from a melt-refining crucible is to convent it to free-flowing oxide powder by oxidation with a dilute oxygen- argon mixture at 700 to 800 deg C. Two complete runs were made for both demonstrating and pin-pointing difficulties in the drag-out or skullreclamation process. Investigation of the reduction of uranium oxides by liquid magnesium alloys was continued. Two runs were made to demonstrate recovery of plutonium from a magnesium solution by distillation of the magnesium. Operation of a mild steel corrosion loop for circulating a U-Mg- Cd alloy at 550 deg C was terminated after 4800 hr of trouble-free operation. The solubility of titanium in liquid cadmium was found to vary between 0.047 at.% at 449 deg C to 0.15 at. % at 651 deg C. The solubility of uranium in liquid lead over the temperature range from 415 to 802 deg C is given. The solubility of uranium in cadmium-magnesium solutions containing up to 72 wt.% Mg at 6l0 deg C was found to decrease smoothly from about 2 wt.% in pure cadmium to about 0.002% in72 wt.% Mg. The partition coefficients of a number of representative fissile and fission product elements between the immiscible liquids aluminum and cadmium at 680 to 688 deg C were measured. The heat of combustion of tungsten disulfide in oxygen was determined to be DELTA E/sub c//sup o//M =-l939.29 plus or minus 0.55 cal/ g for the reaction. The heat of formation of ZrF/sub 4/ was determined by combustions of Zr in F/sub 2/. Two series of calorimetric combustions of B in F/ sub 2/ were carried out. Fuel-Cycle Applications of Volatility and Fluidization Techniques. The Direct Fluorination Volatility Process is being developed to recover uranium and plutonium from spent uranium oxide, Zircaloy-clad fuel elements of the type used in the Dresden nuclear power plant. A study of the kinetics and mechanism of the decomposition of PuF/sub 6/ vapor was initiated. The reaction of PuF/sub 6/ with SF/sub 4/ was investigated. The reaction of SF/ sub 4/ with UO/sub 3/ to produce UF/sub 6/ may be used as a basis for a fuel- recovery process. Conversion of UO/sub 2/ to UC/sub 3/ by means of air and nitric acid vapor and also by means of oxygen and NO/sub 2/ was investigated between 350 and 500 deg C. Several aspects of the Direct Fluorination Process are being studied for the recovery of uranium from highly enriched U-Zr alloy fuels. Experiments incorporating a 2-zone reaction scheme for reacting Zr with HCl-HF gas mixtures were initiated. Laboratory data were obtained on reaction rates of Zircaloy-2 with various mixtures of HF and HCl at various temperatures. A series of fused salt dissolutions of synthetic Zr-U fuel assemblies was carried out in the graphite pilot plant dissolver according to a semicontinuous flowsheet. The conversion of UF/sub 6/ to UO/sub 2/ by direct reaction with steam and hydrogen is being investigated. The first phase of the experimental work in the 6-in. multistage fluid-bed reactor designed to achieve controlled downward transport of solids using external vibrators and without the use of internal downcomers was completed. Reactor Safety. The considerable inhibition of the burning propagation rates of uranium and zirconium by presence of small percentages of halogenated hydrocarbons in air was studied further. The study of ignition of metal powders has continued with studies of ignition of spherical zirconium powders. Preliminary ignition and burning propagation rate studies with plutonium binary alloy foils containing 2 at.% Al, Fe, C, Ni, Mn, and Cr were co