|April 20, 2017
J. Verif. Valid. Uncert
, (2017); doi: 10.1115/1.4036496
Natural convection is a phenomenon in which fliud flow surrounding a body is induced by a change in density due to the temperature difference between the body and fluid. After removal from the Pressurized Water Reactor (PWR), decay heat is removed from nuclear fuel bundles by natural convection in spent fuel pools for up to several years. Once the fuel bundles have cooled sufficiently, they are removed from fuel pools and placed in dry storage casks for long-term disposal. Little is known about the convective effects that occur inside the rod bundles under dry-storage conditions. Simulations may provide further insight into spent-fuel dry storage, but the models used must be evaluated to determine their accuracy using validation methods. The present study investigates natural convection in a 2x2 fuel rod model in order to provide validation data. The four heated aluminum rods are suspended in an open-circuit wind tunnel. Boundary conditions (BCs) have been measured and uncertainties calculated to provide necessary quantities to successfully conduct a validation exercise. System response quantities (SRQs) have been measured for comparing the simulation output to the experiment. Stereoscopic Particle Image Velocimetry (SPIV) was used to non-intrusively measure 3-component velocity fields. Two constant heat flux rod surface conditions are presented, 400W/m2 and 700W/m2, resulting in Rayleigh numbers of 4.5x109 and 5.5x109 and Reynolds numbers of 3,450 and 4,600, respectively. Uncertainty for all measured variables are reported.