Interaction of LaC/sub 2/ and NdC/sub 2/ with SiC in HTGR particles

Conference · Sat Jan 01 04:00:00 EST 1977

OSTI ID:7221094

Pearson, R. L.; Lindemer, T. B.

The reaction rate of either NdC/sub 2/ or LaC/sub 2/ kernels with SiC in coated particles similar to those used in a High-Temperature Gas-Cooled Reactor (HTGR) is essentially identical with that observed in irradiated, TRISO-coated HTGR fuel particles containing UC/sub 2/. The reaction apparently results from destructive distillation of the rare-earth dicarbide in the kernel, transport of rare-earth metal gas down the temperature gradient, formation of the dicarbide at the SiC-pyrocarbon interface, and solution of the SiC in the dicarbide along the SiC grain boundaries. The reaction rate necessary to cause SiC coating failure in four years would apparently be achieved at temperatures above approximately 1565K. It appears that much less than 0.003 of the fissile fuel could fail from this reaction; this compares with a proposed large HTGR design failure fraction of approximately equal to 0.0039 for the fissile fuel.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 7221094
• Report Number(s): CONF-770708-5
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210300* -- Power Reactors
Nonbreeding
Graphite Moderated
ACCIDENTS
CARBIDES
CARBON COMPOUNDS
COATED FUEL PARTICLES
COATINGS
FISSION PRODUCT RELEASE
FISSION PRODUCTS
FUEL ELEMENT FAILURE
FUEL PARTICLES
GAS COOLED REACTORS
GRAPHITE MODERATED REACTORS
HTGR TYPE REACTORS
ISOTOPES
PERFORMANCE TESTING
RADIOACTIVE MATERIALS
REACTOR ACCIDENTS
REACTORS
SILICON CARBIDES
SILICON COMPOUNDS
TESTING