CHEMICAL TECHNOLOGY DIVISION, CHEMICAL DEVELOPMENT SECTION B MONTHLY PROGRESS REPORT, MARCH 1960

Consolidated Edison type fuel pellets were irradiated and analyzed, to determine the extent of fracturing, particle size of fines produced, and the rate of dissolution in boiling 13M HNO/sub 3/-0.04M NaF -0.1M Al(NO/sub 3/)3. Fused sodium or potassium hydroxide was used to shatter the pellets at 400 deg C or higher. Similar pellets were dissolved in H/sub 3/PO/sub 4/ and fused ammonium bifluoride. An investigation was made of the thermodynamics and limits of flammability of gases expected during the dissolution of sodium-bonded stainlesssteel-clad fuels in aqua regia or sulfuric acid. The amount of hydrogen evolved during Darex dissolution of 304 stain less steel was studied as a function of the fraction of total dissolving time and the total gas evolved. The rate of dissolution of tin in HF containing H/sub 2/O/sub 2/ was> 10 mg/cm/sup 2/- min at 13 to 72 deg C, but decreased> 10 times at 13 deg C when HF was replaced by NH/sub 4/F. A technique was developed for disintegrating and leaching graphite fuels, which yielded a recovery of 99.85% + uranium from fuels containing approximately 5% uranium. The uranium extraction in the Immi hot- cell facility indicated a 0.33% loss in the mixer-settler using the 6% TBP flowsheet. Yankee Atomic fuel, containing a fissia concentration of 10,000 Mwd/ T uranium, was dissolved by the Darex and Sulfex Processes to determine the amount of acid insoluble residues formed. Solvent extraction studies revealed that thorium and uranium could be costripped from a 30% TBP neutral solution with Al(NO/sub 3/)/sub 3/. Distribution coefficients were determined for thorium and uranium in 30% TBP-Amsco systems. The presence of H/sub 2/O/sub 2/ in Zirflex dissolver solutions was found to decrease the corrosion rates of Hastelloy F, type 309 stainless steel, and Ni-o-nel. Palladium-titanium alloys showed somewhat higher corrosion rates than Ti-45A in Zirflex and fluoboric-nitric acid solutions. Specimens of type 304L stainless steel exposed to Darex-Purex waste solutions continued to show intergranular attack. The presence of borate in Thorex dissolver solutions lowered the corrosion rate of titanium in the solution phase, and eliminated pitting in the vapor phase. The radiation effects on di- sec-butyl phenylphosphonate were investigated. The distillation of degraded 30% TBP in Amsco 125-82 was tested for use in solvent repurification operations. The ruthenium volatility during the evaporation of wastes was reduced from 66 to 79% to 15% in the presence of TBP, and to 7 to 8% in a NO atmosphere, with or without TBP. A study was made of the nitrate-organic reactions taking place when Purex 1WW concentrates containing TBP were processed. A satisfactory method was found for solidifying Sulfex decladding solutions yielding blocks having compression strengths of 3000 psi. A hydroxyl-form strong-base anion exchange resin removed 72% of the gross fission product activity from low-level waste and raised the pH of the effluent water to 11.3. The Purex 1WW diluted waste was made 0.124M in oxalic acid, which increased the breakthrough capacity of Dowex 50 resin for strontium by 2 to 3 and for rare earths> 3. Thermogravimetric and static studies were made of the kinetics of hydrogen reduction of CaSO/sub 4/. (For preceding period see CF-60-3-84.) (B.O.B