Patent Number: 053612884
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a spacer cell S according to this invention is shown. Spacer cell S includes upper octagonal crown C.sub.1 and lower octagonal crown C.sub.2. In the following description, crown C.sub.1 will first be described. Thereafter, the differences between crown C.sub.1 and crown C.sub.2 will be set forth. Finally the respective spring legs 22 and stop legs 26 extending between the crowns C.sub.1 and C.sub.2 will be described. Crown C.sub.1 is octagonal in shape. It includes full height panels 12, 14, 16, and 18. These respective panels are interconnected by half height panels 11 between full height panels 18 and 12, half height panel 13 between full height panels 12 and 14, half height panel 15 between full height panels 14 and 16, and finally half height panels 17.sub.a and 17.sub.b between full height panels 16 and 18. A complete octagon having equal length sides is formed. Crown C.sub.2 differs from crown C.sub.1 in that the respective half height panels 11', 13', 15' and 17.sub.a ', 17.sub.b ', all extend upwardly with respect to cell S of FIG. 1. Thus it can be seen that the half height panels of crown C.sub.1 are defined to the inside of cell S. Likewise, it can be seen that the half height panels of crown C.sub.2 are defined to the outside of cell S. These features will become important when considering the mating relationship of the respective cells illustrated in FIGS. 2 and 3. Paired spring legs 22 are easy to understand. Each leg begins at a full height panel 16 or 18 in crown C.sub.1 and extends to a corresponding full height panel 16' or 18' in crown C.sub.2. For biasing a fuel rod, a bias point is formed by inwardly arcuate portion 24 medially located in each leg 22. It will be observed that the spring legs 22 are adjacent one another. Paired stop legs 26 are likewise easy to understand. Each leg begins at a full height panel 12 or 14 in crown C.sub.1 and extends to a corresponding full height panel 12' or 14' in crown C.sub.2. For stopping a biased fuel rod in a centered disposition with respect to cells, stop points are formed by inwardly arcuate portions 28 distally located in each leg against a crown C.sub.1 or C.sub.2. It will be observed that the stop legs 26 are adjacent one another. Thus it will be understood that each cell S includes at its two stop legs four inwardly arcuate stop portions 28 for the centering of the fuel rods. Further, it will be seen that each cell S includes at its spring legs two inwardly biased spring portions 24. Consequently, bias of a fuel rod R onto the four stops by two spring portions occurs. Referring to FIG. 2, cells S.sub.1 and S.sub.2 are shown about to be joined. Cell S.sub.1 has crown C.sub.1 at the top and crown C.sub.2 at the bottom. Conversely, cell S.sub.2 has crown C.sub.2 at the top and crown C.sub.1 at the bottom. Turning to FIG. 3, the fitting between the mating horizontal edges of respective half height walls of respective crowns C.sub.1 and C.sub.2 can easily be understood. Specifically, it will be seen that respective half height walls 11 of first crown C.sub.1 fits with half height wall 15' of crown C.sub.2. Likewise, half height wall 13 of second crown C.sub.1 fits with vertically aligned and substantially co-planar half height walls 17.sub.a ' and 17.sub.b ' of crown C.sub.2. It takes little imagination to understand that a continuum of joined crowns C.sub.1 and C.sub.2 will form a crown plane at the top and bottom of each spacer matrix. Referring to respective FIGS. 4A, 4B and 4C, two cells S.sub.1 and two cells S.sub.2 are shown joined to form a matrix of four such cells. Cells S.sub.1 have respective crowns C.sub.1 on top and crowns C.sub.2 on the bottom. Conversely, cells S.sub.2 have respective crowns C.sub.2 on top and crowns C.sub.1 on the bottom. It will further be understood that just as crown C.sub.1 and C.sub.2 form a crown plane on the top, crowns C.sub.2 and C.sub.1 will form a crown plane on the bottom. Joining of the respective crowns C.sub.1 and C.sub.2 is easy to understand. Referring to FIG. 3, welds are made at the top of crown C.sub.1 and C.sub.2 at the junctions of the full height walls. Referring to FIG. 4A, welds are made at the junctions 30. Referring to FIG. 5, a spacer Z having an outside band B.sub.o for abutting a fuel bundle channel and an inside band B.sub.i for abutting a water rod is illustrated. For the convenience of the reader, the orientation of cells S.sub.1 and S.sub.2 is illustrated in the lower left corner of the spacer array--the remainder of the array being a continuum. Adjacent band B.sub.o and B.sub.i it is desirable to have full height walls in order to weld at the tops of the cells S.sub.1 to the bands. Accordingly in FIG. 6, a full height wall 13" is illustrated in crowns C.sub.1. It will be noted that since on crown C.sub.2, half height wall 13' is formed to the outside of cell S.sub.1, a full height wall is not needed. Referring to FIG. 7, a fuel bundle B is illustrated surrounded by a channel C. Channel C is broken away to show a matrix of fuel rods R having a central water rod W. Fuel rods extend between lower tie plate P.sub.1 and upper tie plate P.sub.u. The locations of two spacers Z is schematically illustrated. The disclosed invention will admit of modification. For example, the half height walls here preferred will admit of modification. Crowns C.sub.1 and C.sub.2 could be provided with other mating upper and lower edges. For example, such edges could include repeating curved patterns. All that is required is that when the respective edges are juxtaposed, mating of the crowns to form a single layer occurs. It will be further observed that compared to the Inconel spacers of the prior art, the Zircaloy construction here utilized requires a heavier and thicker metallic construction, especially for the Zircaloy spring legs 22. Accordingly, and over Inconel equivalents, the legs are on the order of 100% thicker.