THERMAL STABILITY STUDIES OF GRAPHITE-MATRIX FUEL SYSTEMS. UNCOATED URANIUM-THORIUM CARBIDE FUEL AND PYROLYTIC-CARBON-COATED CARBIDE FUEL

Technical Report · Wed Jan 23 04:00:00 EST 1963

OSTI ID:4690839

Goeddel, W V; Lonsdale, H K

The thermal stability of graphite-matrix fuel systems containing both uncoated and pyrolytic-carbon-coated carbide fuel particles was evaluated in the temperature range of 1400 to 2000 deg C and for times of up to one year. No gross migration of uranium or thorium within the compacts was observed. Preferential vaporization of carbon from the surface of compacts was noted. Failure of some of the coated particles in thermal-gradient tests was found to be caused by the movement of the particle through the coating on the high- temperature side; this was named the amoeba effect.'' Tests at temperatures of 1500 deg C and below showed that there should be no thermal instability of Peach Bottom coated particles for periods of at least three years (reference core life). The presence of atmospheric impurities did not significantiy contribute to the vapor-phase transport of thorium or uranium. Also, the rate of loss of metals from the compacts is determined by the vaporization step and is not diffusion- limited. (auth)

• Research Organization: General Atomic Div., General Dynamics Corp., San Diego, Calif.
• NSA Number: NSA-17-032570
• OSTI ID: 4690839
• Report Number(s): GA-2880
• Country of Publication: United States
• Language: English

Related Subjects

AMOEBA
CARBON
COATING
DIFFUSION
EVAPORATION
FAILURES
FUEL ELEMENTS
GASES
GRAPHITE
HIGH TEMPERATURE
IMPURITIES
LOSSES
METALS, CERAMICS, AND OTHER MATERIALS
MICROORGANISMS
MOTION
PARTICLES
PYROLYSIS
STABILITY
SURFACES
THORIUM
THORIUM CARBIDES
TRANSPORT
URANIUM
URANIUM CARBIDES
VAPORS