Abstract: Apparatus for the replacement of the guide pins of a guide tube of a pressurized water reactor. The apparatus consists of a rod with clamping means at each end which clamps the guide tube and holds the tube while the bolts connections are removed and then imparts a slight vertical movement to release the guide pins of the guide tube.

Abstract: The invention relates to a process for the replacement of guide pins of a guiding tube forming part of the top internal equipment of a pressurized water nuclear reactor.While the internal equipment is disposed under water in its storage bay, the two parts of the guiding tube (2) are fastened together by introducing a rod (50) along the axis of the tube and over its entire length, and effecting axial clamping of the tube by members (51, 52) each of which bears against one part of the guiding tube (2). The tube (2) is detached and extracted from the internal equipment, it is decontaminated and transported to a dry treatment zone in which the guide pins are replaced. The tube is transported to the internal equipment storage bay, it is placed back in position in this equipment, it is fastened and the connection between the two parts of the tube is detached. The invention also relates to apparatus for carrying out the process of the invention.