Abstract: A debris filtering skirt configured for use with a flow plate of a bottom nozzle of a nuclear reactor is disclosed herein. The debris filtering skirt includes a base portion defining an opening between a bottom edge and a reactor vessel lower core plate, and the opening includes a dimension configured to position the bottom nozzle a predetermined distance away from the reactor vessel lower core plate. The debris filtering skirt also includes a plurality of holes, and at least one hole of the plurality of holes includes a dimension determined based, at least in part, on a predetermined size of debris capable of traversing through the inlet and the outlet. The dimension of the opening and the dimension of the at least one hole are determined based, at least in part, on a predetermined loss coefficient of the bottom nozzle.

Abstract: A base portion for use in a bottom nozzle of a fuel assembly in a nuclear reactor includes a top surface, a bottom surface, and a plurality of vertical wall portions arranged in a generally squared grid-like pattern which extend between the bottom surface and the top surface and which define a plurality of non-circular passages passing between the bottom surface and the top surface through the base portion.

Abstract: A base portion for use in a bottom nozzle of a fuel assembly in a nuclear reactor includes a top surface, a bottom surface, and a plurality of vertical wall portions arranged in a generally squared grid-like pattern which extend between the bottom surface and the top surface and which define a plurality of non-circular passages passing between the bottom surface and the top surface through the base portion.

Abstract: A nuclear fuel assembly having a bottom nozzle with protrusions that extend from the upstream (lower or fluid entry) and downstream (upper or fluid exit) side of a horizontally supported perforated flow plate. The protrusions have a funnel-like shape that gradually decreases the lateral flow area on the upstream side of the perforated flow plate and gradually increases the lateral flow area on the downstream side of the perforated plate. The protrusions on the downstream side are preferably recessed to accommodate the ends of the fuel rods.

Abstract: A nuclear fuel assembly having a bottom nozzle with protrusions that extend from the upstream (lower or fluid entry) and downstream (upper or fluid exit) side of a horizontally supported perforated flow plate. The protrusions have a funnel-like shape that gradually decreases the lateral flow area on the upstream side of the perforated flow plate and gradually increases the lateral flow area on the downstream side of the perforated plate. The protrusions on the downstream side are preferably recessed to accommodate the ends of the fuel rods.