Patent Number: 
Section: claims

1. A debris retention assembly that is configured to be disposed across a flow path through a lower tie plate of a fuel assembly, wherein the flow path is substantially straight, the debris retention assembly comprising:a debris filter configured to be disposed across the flow path, the debris filter comprising filter openings that are configured to impede debris; anda debris retention device positioned upstream from the debris filter with respect to a forward direction of flow along the flow path, the debris retention device comprising:a forward flow channel that is configured to be positioned across the flow path such that the flow path is through the forward flow channel, the forward flow channel comprising at least one channel opening that is larger than the filter openings, wherein the at least one channel opening is configured to allow debris to flow therethrough to the debris filter in the forward flow direction; anda debris tray that opens to an upstream side of debris retention device,wherein the forward flow channel is positioned substantially at the center of the debris retention device and the debris tray is positioned substantially at the perimeter of the forward flow channel. 2. The debris retention assembly of claim 1, wherein the debris tray is perforated. 3. The debris retention assembly of claim 1, wherein the forward flow channel comprises a cylinder that is substantially parallel to the flow path, wherein the channel opening is through the cylinder. 4. The debris retention assembly of claim 1, wherein the forward flow channel includes a matrix of cylinders that are substantially parallel to the flow path, the at least one channel opening comprising a plurality of channel openings through the matrix of cylinders. 5. The debris retention assembly of claim 1, further comprising an enclosure that interconnects the debris filter and the debris retention device. 6. The debris retention assembly of claim 5, further comprising a debris retention cavity defined between the debris filter and the debris retention device. 7. The debris retention assembly of claim 1, wherein the forward flow channel is configured to allow flow to enter the debris retention assembly in an unobstructed, relatively linear path and does not substantially change the direction of the flow. 8. The debris retention assembly of claim 1, wherein the at least one opening includes at least one aperture. 9. The debris retention assembly of claim 1, wherein the debris tray is configured to allow flow therethrough and to impede debris. 10. A lower tie plate of a fuel assembly, comprising:an inlet nozzle;a housing comprising a cavity, wherein the cavity expands outwardly with respect to the inlet nozzle and defines a substantially straight flow path through the lower tie plate;a debris filter positioned in the cavity and disposed across the flow path such that the flow path is through the debris filter, the debris filter comprising filter openings that are configured to impede debris; anda debris retention device positioned in the cavity and upstream from the debris filter with respect to a forward direction of flow along the flow path, the debris retention device comprising:a forward flow channel that is disposed across the flow path such that the flow path is through the forward flow channel, the forward flow channel comprising at least one channel opening that is larger than the filter openings, wherein the at least one channel opening is configured to allow debris to flow therethrough to the debris filter in the forward flow direction; anda debris tray that opens to an upstream side of debris retention device,wherein the forward flow channel is positioned substantially at the center of the debris retention device and the debris tray is positioned substantially at the perimeter of the forward flow channel. 11. The lower tie plate of claim 10, further comprising a debris retention cavity defined between the debris filter and the debris retention device. 12. The lower tie plate of claim 10, wherein the debris tray is configured to allow flow therethrough and to impede debris. 13. The lower tie plate of claim 10, wherein the forward flow channel includes a matrix of cylinders that are substantially parallel to the flow path, the at least one channel opening comprising a plurality of channel openings through the matrix of cylinders. 14. The lower tie plate of claim 10, wherein the debris tray is perforated. 15. The lower tie plate of claim 10, wherein the forward flow channel comprises a cylinder that is substantially parallel to the flow path, wherein the channel opening is through the cylinder. 16. The lower tie plate of claim 10, wherein the forward flow channel includes a matrix of cylinders that are substantially parallel to the flow path, the at least one channel opening comprising a plurality of channel openings through the matrix of cylinders. 17. The lower tie plate of claim 10, further comprising an enclosure that interconnects the debris filter and the debris retention device.