EFFECT OF FABRICATION PARAMETERS AND MICROSTRUCTURE ON THE MECHANICAL STRENGTH OF UO2 FUEL PELLETS

The mechanical strength of UO2 fuel pellets prepared using representative commercial fuel fabrication practices have been measured using a biaxial flexure test. The effect of variation of fabrication parameters within the range used by commercial fuel fabricators as well as selected extra conditions, including fuel powder source, mixed oxide and burnable poison fuels, and test specimen size have been studied. Results show that porosity, and in particular pore size distribution, most significantly influences the pellet strength. Co-relations between strength, microstructure and manufacturing procedures are discussed. © 1979.