GB1090535A - Improvements in or relating to assemblies of non-deformable elongated bodies - Google Patents

Abstract

1,090,535. Fuel elements. UNITED KING- DOM ATOMIC ENERGY AUTHORITY. Oct. 20, 1965 [Sept. 29, 1964], No. 39545/64. Heading G6C. [Also in Division F4] In an assembly of fuel rods in which the axes of the rods are parallel to one another and form an ordered array, the rods are locked in the array by flexible strip members extending transversely through the array with their faces in contact with the rods, the strip members being provided in a plurality of transverse directions to effect the locking, each strip member being free of interconnection with any other strip member within a zone of the assembly bounded by the outermost fuel rods, and making line contact once only with any one fuel rod. In the example described, there are three groups 1 to 12, 13 to 25, and 26 to 36 of stainless steel strips, the strips of each group lying in a common plane and parallel to one another. The ends of the strips in each of the three groups are attached to three separate hexagonal, stainless steel frames 37a, 37b and 37c by spot welding them into slots cut into the ends of the frames. Adjacent frames abut one another but are not connected together. The strips when viewed from the end of frame 37a appear to form a honeycomb, in the cells of which fuel rods are located. The strips may be corrugated or otherwise shaped to provide the desired spacing between the rods. Small variations in the diameter of the rods are taken up by the flexing of the strips upon insertion of the rods. The strips forming each group in the example described lie in transverse flat planes which are normal to the axes of the rods. This is not, however, essential and the planes of the different groups may be inclined to each other and to the axes of the rods to promote flow of coolant over the rods. Furthermore, the strips of each group may have their edges curved in the axial direction of the assembly to lie in transverse surfaces having a generally concave shape or any other desired shape to assist mixing of the coolant. Similarly, the strips may be formed with portions of their faces between adjacent rods displaced at an angle to the axial direction to impart a radial component to the coolant flow. The invention is not limited to the configuration described and the strips may be arranged in two directions at right angles to produce a square lattice. Any number of groups of strips can be used as desired, the number being governed primarily by the length of the rods.