Patent Number: 043269184
Section: summary

The present invention relates generally to the storage of spent nuclear fuel and more particularly to a low cost, uncomplicated and yet reliable technique for storing spent nuclear fuel safely. The problem with storing spent (actually partially spent) nuclear fuel is not a new one. Delays in reprocessing have resulted in a particular need for interim storage capability for the spent fuel. Many conventional options exist such as storage pools at or away from reactor sites. However, their implementation is characterized by high cost, long lead times and/or other logistic limitations such as shipping cask availability. As will be seen hereinafter, the present invention eliminates or at least minimizes these constraints by permitting on site or at least localized storage at a relatively low cost using readily available materials. In view of the foregoing, an object of the present invention is to provide an uncomplicated, economical and yet reliable and safe technique for storing spent fuel from a nuclear reactor. Another object of the present invention is to provide a nuclear fuel storage technique which utilizes readily available components. A more specific object of the present invention is to provide an assembly for storing spent fuel, which assembly has a predesigned cooling capability while, at the same time, automatically compensating for a malfunction in this capability. Another more specific object of the present invention is to provide a fuel storage assembly which utilizes the same means for protecting the assembly against cooling malfunction while, at the same time, serving as a heat transfer media, a neutronic poison and as an absorber/combining agent for any non-gaseous material inadvertently released from the contained fuel rods. As will be described in more detail hereinafter, the storage assembly disclosed herein is one which has housing means adapted for positioning underground and including a closed inner chamber for containing the nuclear fuel, e.g., the fuel rods. A thermally conductive member is located partially within the inner chamber and partially outside the housing means for transferring heat generated by the contained nuclear fuel from the housing chamber to the surrounding ground. In accordance with the present invention, particulate material is located within the chamber and around the nuclear fuel contained therein. This material is seclected so as to serve as a heat transfer media between the contained nuclear fuel and the heat transferring member while, at the same time, standing ready to fuse into a solid mass around the contained nuclear fuel if the heat transferring rod malfunctions or otherwise fails to transfer the heat generated by the fuel out of the chamber in a predetermined manner.