| 摘要 |
PROBLEM TO BE SOLVED: To uniformly cool fuel rods in fuel assemblies and moderate neutron by arranging water rods on the periphery of the fuel assemblies of a super critical water reactor. SOLUTION: Fuel rods 1 are arranged in square grids, and inner water rods 2 are arranged in between fuel rods 1. Around the outermost fuel rods 1, outer water rods 3 are arranged without gaps so as to resolve lack of moderation of neutron at outermost fuel rods 1. Since a flow path between a channel box and fuel rods is eliminated, coolant flow path in fuel rods 1 becomes uniform. For supporting fuel assemblies in the structure, support columns 6 are arranged at the corners and channel box is not used for it. In this manner, neutron absorption by the channel box can be avoided. Control rods 5 are of a cluster structure and inserted in the inner water rods 2. For supplying coolant to the water rods, a part of feed water is guided to the upper dome and supplied through control rod guide tubes from fuel assembly upper part. COPYRIGHT: (C)2004,JPO
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