Thermalhydraulic Simulations for Plate-Type Nuclear Fuel Elements

Abstract

Experimental simulations and measurements have been conducted to investigate the thermalhydraulics of plate-type nuclear fuel elements. This fuel geometry is used in the McMaster Nuclear Reactor (MNR) and in other research reactors. Previous studies of the flow rate through individual elements, or flow distributions within them , have been either lost in obscurity or based on models and data that are too simplistic. An experimental system simulating flow for a single element was developed to examine flow behavior. Axial pressure drop profiles showed entrance and exit effects in channel flow. Subchannel analyses further revealed a non-uniform flow distribution among the channels. Measurement of flow rate through an element at various locations in the MNR core showed no significant variation in flow rate among the core sites. However, the flow rate through a 10-plate element was found to be higher than that through an 18- plate element, as expected. These flow rate determinations will serve to increase the accuracy of heat transfer calculations for a better estimate of fuel surface temperatures. Also, the effect of mixing 10-plate and 18-plate elements in the core will be better understood.