Studies on Zircaloy Fuel Clad Ballooning in a Loss-of-Coolant Accident—Results of Burst Tests with Indirectly Heated Fuel Rod Simulators
SourceBurst tests with indirectly heated fuel rod simulators were performed under cooling and temperature conditions postulated for a loss-of-coolant accident (LOCA) of a pressurized water reactor (PWR). The tests were designed to investigate the ballooning behavior of Zircaloy fuel rod claddings and to determine the resulting coolant channel blockage in a rod bundle.
The deformation behavior of the Zircaloy cladding tubes was found to be influenced mainly by local effects due to nonuniform temperature distributions. Single rod and bundle tests exhibited large azimuthal and axial temperature differences. This resulted in relatively small and axially limited strains of the Zircaloy cladding tubes and a tolerable coolant channel blockage in the rod bundle.