Patent Number: 053735404
Section: description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, it is seen in FIG. 1 and 2 that the invention is generally indicated by the numeral 10. Spent nuclear fuel shipping basket 10 is generally comprised of shell 12, cruciforms 14, and ring supports 16. Shell 12 is provided with end plate 18 at its lower end to support fuel cans 20 that are loaded in shell 12. Drain holes 22 are provided across end plate 18 to allow drainage of any liquid from fuel cans 20 that may accumulate in shell 12. Cover plate 24 is provided for the top end of shell 12. Shell 12 is preferably formed from stainless steel. As seen in FIG. 1, the lower end of shell 12 is provided with a thicker wall section than the upper wall section to allow for shielding at the portion of basket 10 that would normally receive the end fittings of a fuel assembly. This provides for integral shielding without the need for additional parts and weight. As seen in FIG. 2, shell 12 may be notched on the interior diameter as indicated by the numeral 26 for receiving fuel cans 20. Notches 26 provide for radial clearance of fuel cans 20 within shell 12 and allow for thermal growth differences between shell 12 and cans 20. Notches 26 also allow the internal loads of cans 20, the payload, neutron absorber material dead weight, and operating and accident loads to be reacted into shell 12 with a more uniform load distribution than could be achieved with a strict corner point contact with cans 20. A plurality of cruciforms 14 best seen in FIG. 3 are provided to fit between fuel cans 20. The ends of each cruciform 14 are L-shaped to provide a complementary fit of adjacent cruciforms. As seen in FIG. 1, cruciforms 14 extend the full axial length of shell 12. Cruciforms 14 are formed from material suitable to serve the purposes of providing criticality control, acting as a heat transfer material to transfer heat from the interior of shell 12 to its exterior, and also aiding in maintaining geometry control of the spent nuclear fuel assemblies in conjunction with shell 12. In the preferred embodiment, cruciforms 14 are formed from borated aluminum alloy but may be formed from any other suitable material such as borated copper. Cruciforms 14 are sized to receive fuel cans 20 while maintaining contact with fuel cans 20 to provide effective heat transfer. A plurality of ring supports 16 are spaced apart axially along the length of shell 12 and are shaped to fit the contour of cans 20 loaded into shell 12 for effective operating and accident load transfer to shell 12. In the preferred embodiment, ring supports 16 are formed from aluminum alloy. In operation, shipping basket 10 is designed to increase payload while reducing shipping weight and may be used with any suitable shipping cask. The configuration is designed to transmit normal operating and accident loads from the payload by stainless steel fuel cans 20 through ring supports 16 to shell 12 and into the shipping cask. Because many varying and differing embodiments may be made within the scope of the inventive concept herein taught and because many modifications may be made in the embodiment herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.