The Measurement of Radial Power Distributions in a Triga Fuel Element during Reactor Power Excursions

The time- and space-dependent temperature distribution within a TRIGA Mark II fuel element has been measured during a series of power excursions. The temperatures were obtained from 14 thermocouples welded to the uranium-zirconium hydride fuel at various radial locations. The experimental temperatures were used to solve the radial time-dependent heat conduction equation for the local heat generation rate (power density) as a function of radius and time during each pulse. Within the accuracy of the measurement, the radial power profile was found to be independent of the fuel temperature.