The invention relates to a connecting assembly of a centering pin (10) on a core grate (3) of the reactor pressure vessel (1) of a pressurized-water reactor, which centering pin is used to center a fuel element (2), wherein the centering pin (10) is retained in an accommodating bore (16) of a plate (4) present on the core grate (3), with an expanded projection (19) protruding from the accommodating bore (16), in such a way that a form closure is formed. In a pre-assembly state, in which said form closure does not yet exist, the fixing segment (18) is a hollow cylinder, which has, over the entire length of the hollow cylinder, an outer circumferential surface (27) that extends on the lateral surface of a circular cylinder having uniform outside diameter (26). In a final assembly state, the projection (19) is expanded as a consequence of an expansion by means of an expanding tool in such a way that said form closure is formed.