Advertisement

Activated Sintering of Uranium Monocarbide

  • J. P. Hammond
  • G. M. AdamsonJr.

Abstract

The difficulties encountered in conventional sintering of uranium monocarbide impose serious economic restrictions on the use of this potentially important nuclear fuel. At the high temperatures ordinarily used for sintering, chemical control of the carbide is ineffective and the resultant density is not attractively high. Sintering aids alleviate these difficulties, but any microconstituents resulting from the additive should be eliminated to avoid adverse effects in service.

Three processes have been developed using different sintering aids to consolidate high-purity uranium monocarbide powders below 1600°C to compacts having densities ranging from 95 to greater than 97% of theoretical. Our additives were 7.5% UAl2, 0.75% UBe13, and 0.75% U3Si2; during sintering they were eliminated by either evaporation or dissolution into the carbide. The U3Si2 process holds the greatest promise, since it showed near insensitivity to variations in charge-carbon content and proved highly effective even for UO2-derived carbide powder that has a high oxygen content.

To aid interpretation of the sintering mechanisms, we determined pertinent pseudobinary phase diagrams and derived tentative ternary isotherms at the sintering temperatures. An important feature of these processes was an initial stage in which reactive metal vapor issued from the additive and promoted substantial shrinkage. When highest densities were obtained, this stage was generally followed by liquid-phase sintering. Single-phase compacts were ultimately achieved by either dissolution within the matrix or carburization of the residual constituent.

Keywords

Excess Carbon Carbide Powder Vacuum Sinter Versus 3Si2 Uranium Carbide 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Nichols, R. W., “Ceramic Fuels—Properties and Technology,” Nucl. Eng. 3: 324 (1958).Google Scholar
  2. 2.
    Kalish, H. S., and F. B. Litton, “Powder Metallurgy Fabrication of Uranium Carbide,” American Society for Metals—Atomic Energy Commission Conference, Philadelphia, Pennsylvania, October 17, 1960.Google Scholar
  3. 3.
    Korchynsky, M., Powder Metallurgy of Uranium Carbide, Metals Research Laboratories Report, Union Carbide Metals Company, Niagara Falls, New York (April, 1961).Google Scholar
  4. 4.
    Speidel, E. O., Reactor Materials 6(1): 46 (February 1963).Google Scholar
  5. 5.
    Taylor, K. M., C. H. McMurtry, and J. C. Anderson, “Sintering Characteristics of UC and (U, Pu)C with and without Small Additions of Nickel,” Symposium on Carbides in Nuclear Energy, Harwell, England, Nov. 5–7, 1963, The Macmillan Company (London), 1964.Google Scholar
  6. 6.
    Harder, B. R., and R. G. Sowden, “Vacuum Sintering of Uranium-Plutonium Carbide,” Symposium on Carbides in Nuclear Energy, Harwell, England, Nov. 5–7, 1963, The Macmillan Company (London), 1964.Google Scholar
  7. 7.
    McLaren, J. R., M. C. Regan, and H. J. Hedger, “Sintering Behavior of Uranium Carbide,” Symposium on Carbides in Nuclear Energy, Harwell, England, Nov. 5–7, 1963, The Macmillan Company (London), 1964.Google Scholar
  8. 8.
    Hammond, J. P., J. D. Sease, and C. Hamby Jr., “Uranium Carbide Fabrication with UAl2 as Sintering Aid,” 4th Uranium Carbide Conference, East Hartford, Connecticut, May 20–21, 1963, TID-7676 (1964), pp. 145–153.Google Scholar
  9. 9.
    Hammond, J. P., and G. M. Adamson Jr., “Fabrication of Uranium Monocarbide with a Volatile Sintering Temperature Depressant,” Symposium on Carbides in Nuclear Energy, Harwell, England, Nov. 5–7, 1963, The Macmillan Company (London), 1964.Google Scholar
  10. 10.
    Bourgette, D. T., Preparation of Stoichiometric Uranium Monocarbide Cylinders, ORNL-TM-309 (Oct. 4, 1962).CrossRefGoogle Scholar
  11. 11.
    Taylor, K. M., and T. H. McMurtry, Summary Report, Synthesis and Fabrication of Refractory Uranium Compounds, ORO-400 (February 1961).Google Scholar
  12. 12.
    Hodgman, G D., et al., Handbook of Chemistry and Physics, 44th ed., The Chemical Rubber Publishing Co. (Cleveland), 1962.Google Scholar
  13. 13.
    Mallett, M. W., A. F. Gerds, and H. R. Nelson, “The Uranium-Carbon System,” J. Electrochem. Soc. 99: 197 (1952).CrossRefGoogle Scholar
  14. 14.
    Gordon, P., and A. R. Kaufmann, “Uranium-Aluminum and Uranium-Iron,” J. Metals 2: 182 (1950).Google Scholar
  15. 15.
    Magnier, P., and A. Accary, “The Solubility of Uranium in Uranium Monocarbide,” Symposium on Carbides in Nuclear Energy, Harwell, England, Nov. 5–7, 1963, The Macmillan Company (London), 1964.Google Scholar
  16. 16.
    Accary, A., private communication to J. P. Hammond, Oak Ridge National Laboratory, August 17, 1964.Google Scholar
  17. 17.
    Potter, P. E., “The Effect of Oxygen on the Sintering of UC and (U0.85Pu0 15)C,” Symposium on Carbides in Nuclear Energy, Harwell, England, Nov. 5–7, 1963, The Macmillan Company (London), 1964.Google Scholar
  18. 18.
    Brett, N. B., et al., “The Substitutional Solubility of Oxygen in U-C, (U0.85Pu0.15)-C, and PuC,” Symposium on Carbides in Nuclear Energy, Harwell, England, Nov. 5–7, 1963, The Macmillan Company (London), 1964.Google Scholar
  19. 19.
    Rough, F. A., and A. A. Bauer, Constitution of Uranium and Thorium Alloys, BMI-1300 (June 2, 1958).CrossRefGoogle Scholar
  20. 20.
    Burdick, M. D., H. S. Parker, R. S. Roth, and E. L. McGandy, “An X-Ray Study of the System: UC, UC2, Be2C,” J. Res. Natl. Bur. Std. 54: 217–229 (April 1955).Google Scholar
  21. 21.
    Ivanov, O. S., and T. A. Badajeva, “Phase Diagrams of Certain Uranium and Thorium Systems,” Proc. Intern. Conf. Peaceful Uses At. Energy, 2nd, Geneva, Sept. 1–13, 1958, Vol. 6, pp. 561–563.Google Scholar
  22. 22.
    Boettcher, A., and G. Schneider, “Some Properties of Uranium Monocarbide,” Proc. Intern. Conf. Peaceful Uses At. Energy, 2nd, Geneva, Sept. 1–13, 1958, Vol. 6, pp. 561–563.Google Scholar
  23. 23.
    Kaufmann, A., B. Cullity, and G. Bitsianes, “Uranium-Silicon Alloys,” J. Metals 9(1): 23–27 (Jan. 1957).Google Scholar
  24. 24.
    Glassner, A., The Thermochemical Properties of Oxides, Fluorides, and Chlorides to 2,500° K, ANL-5750 (1957).CrossRefGoogle Scholar
  25. 25.
    Peterson, S., and R. G. Wymer, Chemistry in Nuclear Technology, Addison-Wesley Publishing Co., Inc. (Reading, Mass.), 1963, p. 134.Google Scholar
  26. 26.
    Lenel, F. V., “Sintering in the Presence of a Liquid Phase,” Trans. Met. Soc. AIME 175: 878 (1948).Google Scholar
  27. 27.
    Gurland, J., and J. T. Norton, “Role of the Binder Phase in Cemented Tungsten Carbide-Cobalt Alloys,” J. Metals 4: 1051 (1952).Google Scholar
  28. 28.
    Cannon, H. S., and F. V. Lenel, “Some Observations on the Mechanism of Liquid-Phase Sintering,” Plansee Proc. 1st Seminar, Reutte/Tyrol, 1952, Metallwerk Plansee AG. (Reutte/Tyrol, Austria), 1953, p. 106.Google Scholar
  29. 29.
    Kingery, W. D., “Densification During Sintering in the Presence of a Liquid Phase. I. Theory,” J. Appl. Phys. 30: 301 (1959).CrossRefGoogle Scholar
  30. 30.
    Smith, G. V., R. G. Smith, and A. G. Thomas, “Study of Phase Relationships in the Uranium/Silicon/Carbon System,” Symposium on Carbides in Nuclear Energy, Harwell, England, Nov. 5–7, 1963, The Macmillan Company (London), 1964.Google Scholar

Copyright information

© Metal Powder Industries Federation and The Metallurgical Society of AIME 1966

Authors and Affiliations

  • J. P. Hammond
    • 1
  • G. M. AdamsonJr.
    • 1
  1. 1.Metals and Ceramics DivisionOak Ridge National LaboratoryOak RidgeUSA

Personalised recommendations