Fuel kernel materials for the thorium cycle HTGR

Conference · Fri Jun 29 04:00:00 EDT 1973

OSTI ID:4393178

Stansfield, O. M.; Gulden, T. D.; Harmon, D. P.

From international conference on nuclear fuel performance; London, UK (15 Oct 1973). The thorium cycle HTGR typically employs fissilc particles containing fully enriched uranium and fertile particles containing thorium. Small fuel kernels (~10/sup -5/ cm/sup 3/ in volume) are separated by coating layers and matrix material so that the mechanical and thermal properties of the fuel body are, to a large extent, independent of the fuel kernel properties. This feature gives rise to an advantageous flexibility in kernel selection. Both dioxide and dicarbide kernels of Th and U and solutions of the two have been developed. During irradiation carbide and oxide kernels undergo swelling and accumulate a significant fission product inventory. Interaction between the kernel and outer structural coatings is prevented by an intervendng low-density buffer layer. Kernel migration into the coating up the thermal gradient is exhibited by both carbides and oxides. A limitation of coating penetration due to kernel migration in carbide fuels forms the basis for core thermal design. Thorium oxide is the most stable kernel material with little propensity for migration relative to other oxides and the carbides. Mixed oxide fuels have been favored in European HTR design. In the United States where a segregated thorium cycle is employed, fissile UC/sub 2/ and fertile ThO/sub 2/ kernels have been selected for HTGR fuel based on optimization of performance and predictability under operating conditions. (auth)

• Research Organization: Gulf General Atomic Co., San Diego, Calif. (USA)
• DOE Contract Number: AT(04-3)-167
• NSA Number: NSA-29-000915
• OSTI ID: 4393178
• Report Number(s): GULF-GA-A--12632; CONF-731004--2
• Country of Publication: United States
• Language: English

Related Subjects

*HTGR TYPE REACTORS-- FUEL CYCLE
*THORIUM OXIDES-- FERTILE MATERIALS
*URANIUM CARBIDES-- COATED FUEL PARTICLES
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N77300 --Reactors--Power Reactors
Non-breeding
Graphite Moderated
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PYROLYTIC CARBON
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