Abstract: Fuel-element spacer grid with a uniform grid field having polygonal grid-field units and grid crosspieces associated therewith, the grid crosspieces being formed with burls, fuel rods receivable in the respective grid field being centerable at the outer periphery of the fuel rods respectively, at centering surfaces of the burls of the grid crosspieces and retainable axially parallel to one another, the grid crosspieces having a transition region extending therefrom to the centering surfaces of the burls and formed with inclined surfaces for facilitating introduction and withdrawal of the fuel rods, the burls extending over only part of the axial length of the grid, and the inclined surfaces having an inclination angle .alpha. with respect to the grid plane and to a normal to the axis of the grid crosspiece such that the inclined surfaces, in turn, extend over only part of the axial length of the burls; and method of producing the spacer grids.

Abstract: Fuel assemblies forming cores of gas-cooled reactors, operate at temperatures too high to permit the use of resilient contact elements for holding the fuel rods centered in the openings of the spacer grids of the fuel assemblies, solid and rigid contact elements not relying on resilience, being required. In such cases intercontacting surfaces of the fuel rod metal claddings and the spacer grid contact elements, are capable of sticking together, preventing relative sliding by these surfaces to accommodate thermally induced movements, resulting in the claddings being highly stressed.

Abstract: The individual fuel rods of a fuel assembly are connected to a fission gas exhaust system via perforated end caps. For this purpose, the perforated end caps are provided with external threads and screwed into a rod holding plate of the fuel assembly. In addition to the attachment thus provided, a tight connection to the canals of the fission gas exhaust system, which are built into the rod holding plate, is accomplished thereby at the same time.