PROGRESS ON THE DEVELOPMENT OF URANIUM CARBIDE-TYPE FUELS. Phase II Report on the AEC Fuel-Cycle Program

Technical Report · Tue Dec 27 04:00:00 EST 1960

DOI:https://doi.org/10.2172/4115865· OSTI ID:4115865

Rough, F. A.; Chubb, W. eds.

Investigations in the field of chemical synthesis have demonstrated the feasibility of preparing uranium monocarbide from uranium metal by reaction with methane. The product obtained is suitable for direct compaction and sintering into pellets. Powder metallurgical techniques were developed for cold-pressing and sintering uranium carbide powders containing excess uranium metal to densities above 90% of theoretical. Hot pressing was employed to consolidate uranium carbide powders to densities of essentially 100% of theoretical. The skull arcmelting and casting process for uranium carbide was developed to where it is possible to make a single casting weighing up to 5 kg or several smaller castings having the same total weight. The strength and hardness of uranium carbides are relatively insensitive to composition in the range from 4.8 to 9.0 wt.% carbon. The 7.0 wt.% carbon alloy is slightly harder than the other alloys in the as-cast condition. When heat treated to produce the U/sub 2/C/sub 3/ structure, the 7.0 wt.% carbon alloy has a hardness of about 1100 KHN as compared to about 700 and 500 KHN for UC and UC/sub 2/, respectively. The strength and integrity of uranium carbides are very adversely affected by exposure to moisture. Alloying with refractory carbides alleviates this problem. Alloys of uranium monocarbide with Mo/sub 2/C, NbC, VC, and ZrC show high strength and hardness plus improved resistance to corrosion in Santowax R at 350 deg C, and constitute a new and highly promising class of carbide fuel materials. Uranium monocarbide is compatible with aluminum and magnesium up to about 600 deg C, with mild steel and copper up to about 900 deg C, with stainless steel, Inconel, and zirconium to near or slightly below 800 deg C, and with niobium, molybdenum, and tantalum to about 1200 deg C, depending upon the exact conditions. The activation energy for self-diffusion of uranium in uranium monocarbide is 82 kcal/mole or essentially the same as the activation energy for interdiffusion of uranium and carbon (79 kcal/mole). The rate of interdiffusion is over 500 times faster than the rate of self-diffusion of uranium. Irradiations of uranium monocarbide to burn-ups of 0.01 and 0.03 at.% of the uranium have produced data that suggest that elastic expansion of the lattice reaches its limit between these two exposures. and that the additional stress applied to the lattice by exposures to burn-ups of 0.03 at.% and greater is relieved by reduction of the crystallite size. (auth)

• Research Organization: Battelle Memorial Inst., Columbus, Ohio
• DOE Contract Number: W-7405-ENG-92
• NSA Number: NSA-15-007680
• OSTI ID: 4115865
• Report Number(s): BMI-1488
• Country of Publication: United States
• Language: English

Related Subjects

ACTIVATION
ALUMINUM
CARBIDES
CASTING
CHEMICAL REACTIONS
COLD WORKING
COMPACTS
CORROSION
DENSITY
DIFFUSION
ELASTICITY
ELECTRIC ARCS
ENERGY
EXPANSION
HARDNESS
HEAT TREATMENTS
HOT WORKING
HUMIDITY
IRRADIATION
MAGNESIUM
MELTING
METALLURGY
METALS, CERAMICS, AND OTHER MATERIALS
METHANE
MOLYBDENUM CARBIDES
NICKEL ALLOYS
NIOBIUM CARBIDES
PELLETS
POWDERS
PREPARATION
PRESSING
PRESSURE
SINTERING
STAINLESS STEELS
STEELS
STRESSES
TENSILE PROPERTIES
URANIUM
URANIUM COMPOUNDS
VANADIUM CARBIDES
ZIRCONIUM
ZIRCONIUM CARBIDES