The PhotoFlow design is composed of eight identical triangular photovoltaic panels that are mounted on a 400 liter recycled polyethylene water tank. Many developing nations are located on or near the equator and receive more sunlight and rainfall than just about anywhere else on Earth, so why not make the most of this situation by combining solar power with water storage? That's the logic behind PhotoFlow. Consulting and design company NOS is looking to address this problem with PhotoFlow, a two-in-one concept design that combines solar power generation with water collection and storage. Because of the critical nature of this application, the need for new experiments at representative scales is clearly demonstrated.In many countries around the world the supply of electricity and clean water is often sporadic and of poor quality. Mesh resolution, turbulence modeling, and the tradeoff between steady state and transient solutions are addressed. Segregated (uncoupled) steady state solvers that were tested did not accurately capture the flow field and heat transfer distribution in this application. This paper proposes that there may be reliable CFD approaches to the transfer cask problem, specifically coupled steady-state solvers or unsteady simulations however, both of these solutions take significant computational effort.

Relevant experimental data at these scales are not available in the literature, but some recent modeling studies offer insights into numerical issues and solutions however, the geometries in these studies, and for the experimental data in the literature at smaller scales, all have large annular gaps that are not prototypic of the transfer cask neutron shield. The large-scale geometry of the neutron shield tank, which is typically an annulus approximately 2 meters in diameter but only 10-15 cm in thickness, and the relatively small scale velocities (typically less than 5 cm/s) represent a wide range of spatial and temporal scales that contribute to making this a challenging problem for computational fluid dynamics (CFD) modeling.

In these systems, accurate prediction of natural convection within the neutron shield tank is an important part of assessing the overall thermal performance of the transfer cask system. The primary mode of heat transfer within the transfer cask system is conduction, more » but some cask designs incorporate a liquid neutron shield tank surrounding the transfer cask structural shell. Since the transfer cask system must be passively cooled, decay heat removal from spent nuclear fuel canister is limited by the rate of heat transfer through the cask components, and natural convection from the transfer cask surface. The transfer casks are cylindrical steel enclosures with integral gamma and neutron radiation shields. In the United States, commercial spent nuclear fuel is typically moved from spent fuel pools to outdoor dry storage pads within a transfer cask system that provides radiation shielding to protect personnel and the surrounding environment. Approximate calculations have identified the ranges of values of flow parameters needed to determine the flow regimes occurring in practice.' « less Dimensions and flow rates for the idealized situation correspond to those for typical drying canisters. Fluid flows through an array of holes in the perforated basket support plate then around the simulated elements and out the top. A steady flow of the passivation fluid is introduced at the bottom of the canister via a central tube from the top.

This simulation includes flow phenomena that occur in canisters for high- and/or low-enrichment fuels. A generic idealization of a combined drying more » and passivation approach has been defined, which represents a section of a vertical canister with baskets of SNF elements.

This report summarizes work completed after eight months of a three-year, collaborative project. The objective will be reached by using innovative flow visualization techniques and experimental measurements of the flow field to support computational models. By developing a reliable predictive technique for the energy, mass, and momentum transfer in the presence of surface reactions, transfer and storage systems can be efficiently and safely designed. 'The objective of this research program is to understand the fluid physics when corroded spent nuclear fuel (SNF) elements are passivated by injecting treatment gases into a storage canister.

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