Patent ID: 6621885
Filing Date: 2003-09-16
Classification: G21C,Y02E,Y10T

Abstract:
Apparatus for assembling a spacer grid of a fuel assembly for a nuclear reactor, the grid being constituted by a first set of metal straps of generally rectangular shape that extend parallel to one another, and a second set of metal straps that are rectangular, parallel to one another, and that cross the strap of the first set of straps in planes perpendicular to the straps of the first set, the straps being assembled together by interengagement via slots that are spaced apart at a constant distance in a length direction of the straps, the slots occupying at least half a width of the straps so as to constitute a regular array of rectangular cells, each cell being defined by four walls, each wall being constituted by a portion of a strap that lies between two successive slots, each strap carrying a set of springs projecting from at least one face of the strap over at least a fraction of the portions between the slots of the strap, the assembly apparatus comprising a frame configured to support the straps of the first set of straps so that they are disposed parallel to one another, clamping and engagement arrangement configured to clamp on each of the straps of the second set of straps in succession and to engage them with the straps of the first set of straps in position in the support frame, and at least one comb movable between a disengaged position and an engaged position with each of the straps of the first set when in position in the support frame, the comb occupying a position adjacent to a slot configured to engage a strap of the second set of straps, wherein:the support frame configured to support the straps of the first set of straps is secured to a fixed structure; the clamping and engagement arrangement and the comb are mounted to move in respective planes perpendicular to the straps of the first set of straps in position in the support frame and in a direction parallel to the straps of the first set of straps, on a first carriage itself mounted on a first guide arrangement secured to the fixed structure to move in a direction parallel to a longitudinal direction of the straps of the first set of straps; said first carriage carrying a second guide arrangement configured to guide a second carriage and a third guide arrangement configured to guide a third carriage, on respective first and second sides of the support frame, in planes perpendicular to the straps of the first set of straps and in directions parallel to straps of the first set of straps; said clamping and engagement arrangement being fixed on said second carriage and said comb on said third carriage for being moved towards and away from the support frame in opposite directions, on the first and second sides of the support frame; the clamping arrangement comprises two jaws movable in translation parallely to each other in opposite directions under the control of a cam and studs for retracting springs of a strap of the second set of straps engaged in the clamping arrangement by pressing them into the thickness of the strap.