| US 7,469,030 B2 | ||
| Spacer grid for a fuel unit in a nuclear reactor cooled by light water | ||
| Bruno Bonnamour, Villeurbanne (France); Michel Bonnamour, Lyons (France); Jacques Gauthier, Cailloux sur Fontaines (France); and Hubert Salaun, Lyons (France) | ||
| Assigned to Framatome ANP, Courbevoie (France) | ||
| Appl. No. 10/509,146 PCT Filed Mar. 25, 2003, PCT No. PCT/FR03/00945 § 371(c)(1), (2), (4) Date Sep. 24, 2004, PCT Pub. No. WO03/083877, PCT Pub. Date Oct. 09, 2003. |
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| Claims priority of application No. 02 04034 (FR), filed on Mar. 29, 2002. | ||
| Prior Publication US 2005/0226358 A1, Oct. 13, 2005 | ||
| Int. Cl. G21C 3/34 (2006.01) | ||
| U.S. Cl. 376—438 [376/439; 376/442; 376/443] | 8 Claims |
| 1. A nuclear fuel element comprising a bundle of fuel rods and a framework for holding the bundle, wherein each of the fuel
rods are of substantially cylindrical shape, and said framework comprises a plurality of spacer grids for a fuel assembly
in a light-water-cooled nuclear reactor, for providing a transverse retention of the bundle of fuel rods in mutually parallel
arrangements, at least one of the plurality of spacer grids comprising:
an array of cells juxtaposed and placed in a regular lattice, each bounded and separated from neighboring cells by at least
one peripheral wall which is open at two opposed ends, along a direction of an axis of the cell, the axis being vertical,
so as to receive one of the fuel rods, said one of the fuel rods passing along the cell axis parallel to the peripheral wall,
and
an arrangement for bearing on and retaining the one of the fuel rods in a central position in which an axis of the one of
the fuel rods lies along the axis of the cell, a free space being left between a cylindrical external surface of the one of
the fuel rods and the peripheral wall of the cell, in which the arrangement for bearing on and retaining the one of the fuel
rods in each of the cells housing a fuel rod comprises
a wall having a form of a helical sheet extending transversely in the free space between the external surface of the one of
the fuel rods and the peripheral wall of the cell so as to bear on the one of the fuel rods over a substantial part of the
height of the cell in a direction of the axis of the cell,
wherein the wall having a form of a helical sheet comprises
at least one element in a helical arrangement with respect to the axis of the cell, wherein the at least one element in a
helical arrangement consists of
a part of the peripheral wall of the cell cut in the peripheral wall along a direction inclined to the axis of the cell and
folded so as to constitute a blade-shaped first part of direction transverse to the peripheral wall and a second part folded
with respect to the first part, the second part extending approximately parallel to the peripheral wall and constituting a
bearing surface for the external surface of the one of the fuel rods,
wherein the second part is joined to the peripheral wall of the cell via the transverse first part constituting a spring leaf
retaining the one of the fuel rods and for guiding a cooling fluid in a helical arrangement with respect to the axis of the
cell, and
wherein the second part folded with respect to the first part bears on the one of the fuel rods over a part of the height
of the cell in the direction of the axis of the cell.
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