Patent Number: 050358537
Section: summary

The invention relates to a nuclear reactor fuel assembly including at least one uprightly disposed spacer having a grid of intersecting sheet-metal struts defining meshes therebetween, mutually parallel rods each being disposed in a respective one of the meshes, and strip-like contact springs parallel to the rods, each of the contact springs being disposed in a respective one of the meshes and having two strip ends both being retained on one of the struts, each of the contact springs having a contact location being resilient relative to the strut for contacting a rod, the contact location being spaced apart from both of the strip ends, each of the contact springs having an undulatory transverse curve at the contact location, and the contact springs being continuously smooth and flat from the contact location to the strip ends resting on the strut. A fuel assembly of the type mentioned above is known from Swiss Patent No. 499 850. The contact spring of the known nuclear reactor fuel assembly is located on one side of one strut of the spacer and is secured at both strip ends to the strip ends of an identically constructed contact spring located on the other side of the strut. The undulating transverse curve at the contact locations of the strip-like contact springs for the associated rod is located on the side of the associated strip-like contact spring facing away from the strut. In a nuclear reactor, the fuel assembly is longitudinally exposed to the flow of a coolant, which therefore also flows through the individual meshes in the spacer. This leads to a relatively high resistance to the flow of coolant through the individual meshes of the spacer and therefore through the overall fuel assembly. It is accordingly an object of the invention to provide a nuclear reactor fuel assembly, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and which keeps the flow resistance for the coolant passing through the individual meshes of the spacer and therefore through the overall fuel assembly optimally low. With the foregoing and other objects in view there is provided, in accordance with the invention, a nuclear reactor fuel assembly, comprising at least one uprightly disposed spacer having a grid of intersecting sheet-metal struts defining meshes therebetween, mutually parallel rods, especially fuel rods containing nuclear fuel, each being disposed in a respective one of the meshes, and strip-like contact springs being parallel to the rods and each having a side facing toward and a side facing away from a respective one of the struts, each of the contact springs being disposed in a respective one of the meshes and having two strip ends both being retained on the one strut, each of the contact springs having a contact location being resilient relative to the one strut for contacting a rod, the contact location being spaced apart from both of the strip ends, each of the contact springs having an undulatory transverse curve disposed at the contact location on the side of the contact spring facing toward the one strut, and the contact springs being continuously smooth and flat from the contact location to the strip ends resting on the one strut. As a result, a gap is formed between the rod and the contact spring resting thereon for the coolant flowing through each individual mesh in the longitudinal direction of the fuel assembly in a nuclear reactor, which narrows and widens uniformly. The overall result is an optimally low flow resistance for the coolant of the nuclear reactor fuel assembly. In accordance with a concomitant feature of the invention, the undulatory transverse curve is in the form of a single curve disposed at the contact location, and the contact spring has transition locations adjacent the undulatory transverse curve being unequally spaced apart from the one strut on which the contact spring is retained. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as constructed in a nuclear reactor fuel assembly, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.