LMFBR Vented Assembly Hydraulic Modeling and Testing

摘要

A fundamental uncertainty in designing or evaluating the performance of an LMFBR core composed of vented assemblies is the flow pattern of the coolant through the vents and spaces between the assemblies, as controlled by the vent hydraulic characteristics. The principal difference between a conventional and vented assembly is that a vented assembly has holes cut in the duct wall at locations above the active core region below the above-core load pads. The purpose of the venting is (1) to extend assembly life by pressurizing the core interstitial region (spaces between the assemblies) to reduce duct stress and radial growth, and (2) to reduce the reactor coolant pressure drop by providing an additional bypass flow path to the upper plenum for the coolant after it cools the active core. The paper presents analytical and test results evaluating the vent flow discharge coefficient with respect to the system flow rates and vent geometry. (ERA citation 03:052584)