PROGRESS RELATING TO CIVILIAN APPLICATIONS DURING FEBRUARY 1960

Preliminary results from electrical studies indicate that the "valence- compensated", air-fired U/sub 3/O/sub 8/-La/sub 2/O/sub 3/ solid solutions containing greater than equimolar amounts of La/sub 2/O/sub 3/ are poor conductors. Progress is reported on work devoted to fabrication and evaluation of U/sub 3/O/sub 8/ solid solutions contairing 40. 50 and 60 mole% La/sub 2/O/ sub 3/. and a sample containing 25 mole% Y/sub 2/O/sub 3/ and MgO each. In an investigation on the effects of combined ultrahigh pressure and high temperature on the uranium-- oxygen system and on the reaction of the oxides with various mixed oxides, it was found that U/sub 3/O/sub 8/ has an oxygen-to-uranium ratio of UO/sub 2.7//sub 2/. Corrosion testing of niobium alloys in 600 and 680 deg F water and 750 deg F 1500-psi steam was continued, and results for exposure times ranging up to 308 days are tabulated. In development of niobium-- uranium fuels, corrosion test results were obtained in 224-day exposure to 600 deg F water and in 1500 deg F sedium for 500 hr. In investigations to improve the corrosion resistance and irradiation stability of thorium-- uranium alloys, tensile and creep tests were performed at 600 and 70O deg C. In general fuel element development, techniques were developed for sub-bonding of niobium. In urarium dioxide compaction studies, results of flash roasting to attain off-stoichiometry urarium dioxide powders are tabulated. Prooress is reported in the uranium carbide skull-casting process. in research on methods of preparing high-purity crystals of UO/sub 2/, success is reported by methods involving vapor deposition. The determination of iron by titration to a radiometric end point was found to be very sensitive to the concentration of the tartaric acid complexing agent and sodium acetate buffer. Esters of the methacrylate group were studied to determine the relation of total radiation dose and free-radical-site formation to ester-group structure. Stress-rupture tests are reported at 200 deg C and stresses of 7,000 to 11,000 psi on aluminum35 wt.% uranium alloy and on similar alloys containing 2 and 3 wt.% tin or zirconium. Metallegraphic study of foiled titarium steam coil sections from Purex acid-recovery evaporator showed no structural differences which could account for the fracture; it is thought that failure was caused by mechanical rubbing. Results of 6000 Mwd/t uranium burnup in capsule specimens containing 4.8 wt.% carbon are comparable with those for 4.6 and 5.0 wt,% carbon specimens. Data from neutron activation studies of vapordeposited Al/sub 2/O/sub 3/-clad uranium dioxide particles show that uranium contamination in the cladding surface probably accounts for the Xe/sup 133/ release at low temperatures, and that claddings are not damaged during sphere fabrication or thermal cycling. Study of tanthlum and its alloys under irradiation reveals alterations of properties such as strength and hardness, although ductility is not seriously impaired. Results of static tests in MTR of uranium dispersions in BeO or Al/sub 2/O/sub 3/ and dispersions of UC or UC/sub 2/ in graphite are tabulated. (For preceding period see BMI1409.) (J.R.D.