Year
2010
Abstract
Dry casks are designed to confine spent nuclear fuel in sealed canisters and complex CFD models are used to analyze decay heat removal. Deficiencies and inaccuracies of CFD analyses can be caused by a variety of errors and uncertainties. Validation of heat transfer and fluid flow phenomena in dry casks are used to reduce uncertainties. Discussion of modeling uncertainties focuses on turbulence models which greatly influence the predicted results if not applied correctly. Several approaches to model turbulence are investigated and compared to experimental data and CFD best practice guidelines to minimize turbulence modeling uncertainties for dry cask analysis are given. Discussion also focuses on application uncertainties which are introduced because the application is complex and precise data is not always available. The discussion focuses on the inlet and outlet boundary conditions of ventilated dry storage casks. As cooling air is naturally induced in ventilated dry casks, pressure boundaries are the preferred choice at the inlet and outlet ducts. The pressure gradient in the air flow channel affects the magnitude of the potential buoyancy forces due to spent fuel decay heat and as such, the pressure boundary conditions are very crucial to the simulation uncertainties. Pressure boundary conditions are investigated and compared to experimental data to minimize application uncertainties. Guidelines to avoid uncertainties in the specification of the pressure boundary conditions are given.