Inert gas permeability of High-Temperature Gas-Cooled Reactor (HTGR) coated fuel particles

Technical Report · Thu May 25 04:00:00 EDT 1978

OSTI ID:6742432

Powell, G L

The permeabilities of helium, neon, and argon through the pyrocarbon coating of HTGR, BISO-type, fuel particles from Batch OR2261HT have been determined from gas content measurement made at fixed anneal time intervals under isobaric-isothermal conditions. These measurements are described by a simple diffusion model where: D/sub He/ = 1 x 10/sup -6/ exp-(115.5 Kj mol/sup -1//RT) m/sup 2/s/sup -1/; D/sub Ne/ = 1 x 10/sup -6/ exp-(175.7 Kj mol/sup -1//RT) m/sup 2/s/sup -1/; D/sub Ar/ = 1 x 10/sup -6/ exp-(273.1 Kj mol/sup -1//RT) m/sup 2/s/sup -1/. The concentration (solubility) of the diffusing gas in the pyrocarbon coating is described as an ideal gas stored in pores that constitutes 4.6% of the volume of the coating. A parameter t/sub 1/ = 1.32 x 10/sup -9/ m/sup 2//D s relates the diffusion coefficient to the time required to establish steady state diffusion across the pyrocarbon barrier and can be associated with service life of these fuel particles as gas containers. Extensive annealing (172.8Ks at 2000/sup 0/C) of these fuel particles is accompanied by pore growth in the pyrocarbon barrier and a decrease in the diffusion coefficient.

• Research Organization: Oak Ridge Y-12 Plant, TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6742432
• Report Number(s): Y/DA-7885
• Country of Publication: United States
• Language: English

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Graphite Moderated
ARGON
CARBON
COATED FUEL PARTICLES
COATINGS
CRYOGENIC FLUIDS
DIFFUSION
ELEMENTS
FLUIDS
FUEL PARTICLES
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