Predicting critical flow velocity leading to laminate plate collapse – Cylindrical plates

A new prototypic fuel is presently being developed to support the conversion of the U.S. high performance research reactors (HPRRs). This fuel material is a uranium molybdenum alloy and is clad in aluminum. In order to optimize neutron efficiency and reactor performance characteristics the U.S. HPRR core geometry has been designed to accommodate plate type fuel geometry. The relatively thin plate-type geometry provides susceptibility for mechanical failure under the extreme hydraulic loadings that the fuel is exposed to in-pile. An analytical model has been developed and is described in detail which supports the development efforts of the heterogeneous prototypic fuel, and advances the science of hydro-mechanics. This study investigates a single method for determining the ‘critical flow velocity’ for a laminate cylindrical plate. The objective is accomplished by incorporating a flexural rigidity term into the formulation of critical flow velocity originally derived by Donald R. Miller, and employing super position method to determine the rigidity term. The final outcome of this study results in the development of a single equation for each of three different edge boundary conditions which reliably and comprehensively predicts the onset of plate collapse. Select test cases are performed on this new model and compared against existing models.