Thermal shock testing of ceramic balls representing pebble bed reactor fuel elements

Abstract

A number of sintered ceramic beryllium oxide balls were heated and then quenched in fast-flowing carbon dioxide gas to determine the thermal stress which would crack similar balls containing a small amount of uranium dioxide fuel in the core of a prospective pebble bed nuclear reactor. The stress to crack the average ball was determined using simplifying assumptions, and as the balls were quenched in groups this stress will be used to calculate the allowable heat output of fuel balls in a pebble bed reactor.