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Materials Science Centre, School of Materials, University of Manchester, Grosvenor St., Manchester M1 7HS, UKThe Pd/silicon carbide (SiC) reaction rate in tristructural isotro-pic (TRISO)-coated fuel particles has been studied. We haveshown that it is possible to reduce the attack by palladium sig-nificantlybycontrolling the SiC microstructure. Large grainsizesas well as high coating rates did not increase the attack by Pd aspreviouslythought. The activation energyforthe Pd/SiC reactionobtained for the optimized SiC coatings, 337 kJ/mol, is almosttwice as high as for standard coatings ( B160–190 kJ/mol)and five times higher than for porous samples (67 kJ/mol). Anincrease of the (111) texture component and the characteristics ofthe grain boundaries are suggested as possible reasons for reduc-tion of the Pd/SiC reaction.I. Introduction |
