Patent Number: 044951450
Section: summary

BACKGROUND OF THE INVENTION The present invention relates to the loading of fuel rods with spherical nuclear fuel. In recent years it has been discovered that conventional nuclear reaction fuel composed of fuel pellets encased in cladding tubes may lead to the splitting of the cladding tubes thereby releasing radioactive material to the adjacent cooling water. This splitting is due to an interaction between the pellet and cladding. One way of avoiding this problem is to limit the surface interaction between the fuel and cladding. This may be achieved by loading the fuel cladding tubes with nuclear fuel in the shape of spheres. If three different sizes of spheres are used, than appropriate packing of the spheres into the rods will result in a sufficient density of nuclear fuel to be properly used in a nuclear reactor. One method for loading a fuel rod is to simply drop the spheres into a vertical cladding tube while vibrating the rod to assist in packing. However, this method is not satisfactory for several reasons. The distribution of the particles sizes freely falling from a height of 6 to 12 feet into a cladding tube does not lead to uniform distribution. This method also leads to the trapping of air which requires a longer time to evacuate at the sealing of the tube. In addition, the vibrating packing is extended because of the random loading of the spheres. SUMMARY OF THE INVENTION The invention is a loading probe for the loading of spherical nuclear fuel into a fuel rod. The probe includes a funnel means for receiving the spherical nuclear fuel, the funnel means maintaining a separation of the spherical fuel of different diameters; tubing means corresponding to each of the spherical nuclear fuel diameters, the tubing means of sufficient length so that one end of the tubing means extends about the length of the fuel rod in the load portion; valve means for releasably containing the fuel spheres within said funnel means, said valve means able to release the fuel spheres to the tubing means; gate means between the valve means and the tubing means for regulating the rate of flow of each the spherical fuel as it passes from the funnel means through the valve means into the end of the tubing means away from the fuel rod; and deflector means attached to the end of the tubing means within the fuel rod for mixing the fuel as it emerges from the tubing means;