Experimental investigation of natural convection about drift-emplaced waste canisters

Qun Wang, University of Nevada, Las Vegas


Drift-emplaced waste canisters are under consideration for the long-term storage of high-level spent fuel in the proposed underground repository at Yucca Mountain. These canisters will be placed on pedestals above the floor of the drift and exchange heat with the wall of the drift with air circulating through the repository. To assess the requirements for repository energy management and the ventilation system, flow visualization and heat transfer experiments for natural convection were performed. The experiments used both the smoke generation and the dye injection techniques to obtain the natural convection patterns for 4.9 {dollar}\times{dollar} 10{dollar}\sp4{dollar} {dollar}\le{dollar} Ra{dollar}\sb{\rm d}{dollar} {dollar}\le{dollar} 1.6 {dollar}\times{dollar} 10{dollar}\sp5{dollar} and 1.4 {dollar}\times{dollar} 10{dollar}\sp6{dollar} {dollar}\le{dollar} Ra{dollar}\sb{\rm d}{dollar} {dollar}\le{dollar} 2.9 {dollar}\times{dollar} 10{dollar}\sp7{dollar} in a horizontal eccentric annulus containing heated canisters. This range of Rayleigh numbers included both laminar convection and turbulent convection. In addition, the measured average Nusselt numbers were computed as a function of Rayleigh number for laminar and turbulent flows. The data were compared with the results of previous experimental work.