Theoretical models to predict the transient heat transfer performance of HIFAR fuel elements under non-forced convective conditions
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Date
1987-04
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Publisher
Australian Atomic Energy Commission
Abstract
Simple theoretical models have been developed which are suitable for predicting the thermal responses of irradiated research fuel elements of markedly different geometries when they are subjected to loss-of-coolant accident conditions. These models have been used to calculate temperature responses corresponding to various non-forced convective conditions. Comparisons between experimentally observed temperatures and calculated values have shown that a suitable value for surface thermal emissivity is 0.35; modelling of the fuel element beyond the region of the fuel plate needs to be included since these areas account for approximately 25 per cent of the thermal power dissipated; general agreement between calculated and experimental temperatures for both transient and steady-state conditions is good - the maximum discrepancy between calculated and experimental temperatures for a HIFAR Mark IV/V fuel element is approx 70 deg C and for an Oak Ridge Reactor (ORR) box-type fuel element approx 30 deg C; and axial power distribution does not significantly affect thermal responses for the conditions investigated. Overall the comparisons have shown that the models evolved can reproduce experimental data to a level of accuracy that provides confidence in the modelling technique and the postulated heat dissipation mechanisms and that these models can be used to predict thermal responses of fuel elements in accident conditions that are not easily investigated experimentally.
Description
Keywords
Fuel elements, Loss of coolant, Theoretical data, Reactor accidents, HIFAR Reactor, Fuel plates, Thermal conduction
Citation
Green, W. J. (1987). Theoretical models to predict the transient heat transfer performance of hifar fuel elements under non-forced convective conditions (AAEC/E646). Lucas Heights, NSW: Australian Atomic Energy Commission Research Establishment, Lucas Heights Research Laboratories.