Patent Number: 044366930
Section: summary

TECHNICAL FIELD The field of this invention is the storage of spent nuclear reactor fuel rods. BACKGROUND ART It is conventional to store spent nuclear fuel assemblies in racks on the floor of a storage pool. It would, however, be desirable to increase the storage capacity of a rack. It has been proposed to achieve this by disassembling the rods from the fuel assembly in a remote area of the pool. This may be accomplished, for example, by cutting the top end fitting from the assembly and pulling out the fuel rods. The skeleton of the fuel assembly can then be compacted and disposed of in a commercial burial ground. The fuel rods would be loaded into a canister having approximately the same external dimensions as the fuel assembly. A cap would be sealed on the end of the canister and the canister lowered into a cell in the storage rack. As the rods can be close packed in the canister, it should be possible to achieve a compaction ratio of 1.5:1 to 2:1. In other words, the fuel rods of as many as two fuel assemblies may be stored in one cell of a fuel storage rack. One problem which arises in implementing this concept is a result of the requirement that the rack must be designed to withstand a seismic event. A fuel assembly may weigh on the order of 1,500 pounds and there may typically be one-half inch clearance between the outside of the fuel assembly and the inner wall of a cell. For example, the cell may be 9 inches square and the fuel assembly may be 81/2 inches square. In order to withstand an earthquake, the designer must employ an impact factor. This might be, for example, a factor of 2:1. Thus, for a 1,500 pound fuel assembly, the cell and rack would have to be designed to withstand a 3,000 pound load. In going from fuel assembly storage to loose rod storage at 2:1 consolidation, 3,000 pounds of fuel rods may be placed in each cell. If impact is considered, the cells must be designed for a 6,000 pound load. However, if the impact factor can be disregarded and eliminated, redesign of the cells may be avoided. It would also be desirable to reduce the horizontal seismic loads imposed by a rack on the pool floor. DISCLOSURE OF INVENTION It is an object of the present invention to provide a canister for storing loose, spent nuclear fuel rods within a fuel storage rack while substantially eliminating the impact factor under earthquake conditions. In accordance with this invention, there is provided an elongated canister body of substantially square cross-section which has an open top end and a closed bottom end. The canister is dimensioned to fit within a storage cell of a fuel storage rack. A lateral support pin protrudes outwardly from the bottom end of the canister for containment within the flow hole of the bottom plate of the storage cell. A cap is secured on the open end of the canister and is arranged to avoid impacting against the sidewalls of the storage cell. Means are provided for securing the cap to the canister.