Abstract: Upper and lower core structures of core internals carry a plurality of centering pins which have free ends protruding into recesses in a fuel assembly endpiece. In the case of the upper core structure in particular, the nuts for fixing the centering pins are difficult to access in the event of a subsequent exchange of pins. Therefore, core internals which do not require a nut for securing on the centering pins are preferred. For this purpose, a centering pin is provided with a center bore passing through it. The ends of the center bores facing away from the fuel assemblies are in the form of conically tapering stepped bores. Each stepped bore has a plug which is displaceable in axial direction relative to the centering pin. The peripheral surface of the plug is conically formed in the same direction and with the same pitch as the stepped bore. The centering pin enters into a play-free fitting connection with a bore in a grid plate.

Abstract: Process and holding component for repair of a nuclear reactor fuel assembly spacer support. The holding component is formed from a metal strip, on the free ends of which are introduced elastic projections. After removal of the damaged crosspiece, a holding component partly embracing the fuel rod is locked into a slot of a spacer support by means of its projections.