Design and performance of coated particle fuels for the thorium cycle HTGR

Conference · Thu Jan 24 04:00:00 EDT 1974

OSTI ID:4307504

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

From international conference on physical metallurgy of reactor fuel elements; Berkeley, England, UK (2 Sep 1973). The reference fuel for the Thorium Cycle HTGR, being developed commercially in the United States, utilizes separate fissile and fertile coated particles, which are blended together and bonded into fuel rods by means of a carbonaceous matrix. Fissile particles have TRISO coatings while the fertile particles have BIS0 coatings. Both types of coated particles are designed based on the results of extensive irradiation tests and sophisticated analytical models. The mechanical design of both BISO and TRISO coated particles is aided by analytical stress models using geometrical factors and baaic properties and irradiation behavior of the coating materials as inputs. To minimize the importance of uncertainties in the input data, stress model calculations are always normalized to the results of irradiation tests on fuel particles. The chemical performance of coated particle fuels is dominated by unidirectional migration of the fuel kernel into the coatings along the temperature gradient. This phenomenon is generally referred to as the amoeba effect. The amoeba effect in carbide fuels is shown to be controlled by carbon thermal diffusion in the fuel phase, while in oxide fuels it is apparently controlled by gas phase carbon transport in the accessible void volume within the coated particle. It is demonstrated that with proper knowledge and control of the mechanical and chemical aspects of performance, a variety of coated particle fuel types may be designed to perform adequately under HTGR conditions. 12 references. (auth)

• Research Organization: General Atomic Co., San Diego, Calif. (USA)
• DOE Contract Number: AT(04-3)-167
• NSA Number: NSA-29-031189
• OSTI ID: 4307504
• Report Number(s): GA-A--12628(Rev.); CONF-730912--4
• Country of Publication: United States
• Language: English

Related Subjects

*COATED FUEL PARTICLES-- SPECIFICATIONS
*HTGR TYPE REACTORS-- COATED FUEL PARTICLES
N77300* --Reactors--Power Reactors
Non-breeding
Graphite Moderated
PHYSICAL RADIATION EFFECTS
STRESSES
THORIUM OXIDES
URANIUM CARBIDES