Bureau of Mines / Minerals yearbook: Metals, minerals, and fuels 1972
Year 1972, Volume 1 (1972)
Sondermayer, Roman V.
Thorium, pp. 1201-1208 PDF (856.3 KB)
13 Ruth, J. P. Rare Earth Metals Demand Up for Pipelines in Severe Areas. Am. Metal Market, v. 79, No. 130, July 17, 1972, p. 30. 14 Baranow, S. The Effect of a Hydrogen Preheat-Treatment on the Oxidation Behavior of Ni-Cr-Al-ThO2 Alloys. Met. Trans., v. 3, No. 12, December 1972, pp. 3265—3267. 15 Tomson, J. R. Alloys of Thorium with Certain Transition Metals. VI. The Constitution of Thorium-Nickel Alloys Containing 50%—96% Nickel. J. Less-Common Metals, v. 29, No. 2, October 1972, pp. 183—188. 16 Childs, B. G., P. J. Harvey, and J. B. Hallett. Optical Absorption Spectroscopy of 1'hO~. J. Am. Ceramic Soc., v. 55, No. 11, November 1972, pp. 544—547. 17 Benz, R. Nitride Layer Growth on Liquid Thorium and Solid Thorium Carbon Alloys. J. Electrochem. Soc., v. 119, No. 11, November 1972, pp. 1596—1602. 18 Halbfinger, G. P., and M. Kolodney. Activated Sintering of ThO~ and ThO2-Y2OS with NiO. J. Am. Ceramic Soc., v. 55, No. 10, pp. 519—524. 19 Leitnaker, J. M., M. L. Smith, and C. M. Fitzpatrick. Conversion of Uranium Nitrate to Ceramic Grade for Light Water Breeder Reactor: Process Development. Oak Ridge National Laboratory, Metals and Ceramics Division, ORNL4755, April 1972, p. 54. THORIUMwithout change of power source, which is now necessary every 30 months.13 A dispersion-modified alloy containing thorium with nickel and chromium was under development for use in the space shuttle. Necessary properties of this alloy are high-strength, formability, and good oxidation resistivity at 2,200° F. Research indicated that a 2% to 5% addition of aluminum to the base alloy improved the oxidation resistance of the basic Ni-CrThO system with a loss of strength at elevated temperatures.14 Th-Ni systems were studied over a composition range from 50% to 96% Ni and a temperature range of 1,000° to 1,500 C. Intermetallic compounds were observed that were not previously found. Alloys in this composition range were stable in air. A few alloys were annealed for 14 days at 800° C. Th-Ni alloys showed some similarities to Th-Si alloys." Work on optical absorption spectroscopy of Th02 was extended to purer specimens than those used previously. The fundamental absorption edge for these specimens lies at much higher energy than the apparent edge reported previously. A full analysis of certain crystals by spark-source mass spectrometry indicated that no strong correlation existed between specific band areas and impurity-element concentration. Moreover, purer specimen of fused Th02 revealed new, previously unobserved bands of the Th02 spectrum.l6 Behavior of thorium-carbon alloys in a nitrogen environment at moderate pressures was examined. Results indicated an "uphill" (up a concentration gradient) diffusion of carbon in the ternary solid solution Th (C,N). This explains the tendency for carbon and thorium to segregate in the course of reaction of thorium carbon alloys with nitrogen at moderate pressures.17 Energy.—Effects of additives on the sintering of ThO2 and Th02-Y2O, compacted and loose powders were studied. The investigation showed that small amounts of nickel oxide are potent and increase the rate of sintering of thorium oxide, and the major portion of densification occurs very rapidly and is followed by a much slower process of sintering.'S A new HTGR concept was under investigation. GGA of San Diego, Calif., negotiated a contract with the Atomic Energy 1207 Commission (AEC) for design, engineering, and construction of a nuclear gas-turbine powerplant, which would eliminate the steam-turbine cycle by combining the HTGR with a closed-cycle helium gas-turbine generator. Hot helium at 1,500° C would turn the gas-turbine generator. Benefits of the new concept include savi.ngs in capital costs, improved reactor operating efficiency, and reduced environmental impact since lesser quantities of cooling water are needed. The light water breeder reactor (LWBR) fuel is ThO2 pellets in which 1% to 6% U233 in UO2 form is dissolved. A project was underway to develop a chemical fiowsheet for converting uranium-nitrate solution to ceramic grade U02 powder having desired properties for uniform blending with ThO2 powder and for pressing and sintering to high-density fuel pellets for the LWBR.19 Solvent properties and corrosiveness of liquid sodium, which is used as a coolant in fast-breeder reactors, were the subjects of a study originating in Sweden. A system of corrosion in liquid metals is often accompanied with mass transfer of corrosion products, and alloys form within the bulk phase of the liquid metal. The ThCu system was studied in the temperature range of 200° to 700° C. Reaction products are finely divided and well crystallized at temperatures below the melting points. Sodium apparently does not participate as a catalyst in the process, but does promote
http://rightsstatements.org/vocab/NoC-US/1.0/| As a work of the United States government, this material is in the public domain.| For information on re-use see: http://digital.library.wisc.edu/1711.dl/Copyright