Abstract: The wall member (35a, 35c, 35d) of the enclosure comprises ducts (46a, 46c, 49d) for sampling fluid from or for injecting fluid into a chamber (44) delimited by the enclosure and the outer surface of a receptacle (32) enclosing a fluid at high temperature. The ducts (46a, 46c, 46b) comprise apertures (47a, 47c, 49d) on the inner surface of the wall member and at least one sampling or injection pipe (48, 50) opening onto the outer surface of the wall member. The wall member may be a heat-insulating modular panel for covering the head (32) of the vessel of a pressurized water nuclear reactor.

Abstract: The confining and covering enclosure (10) comprises a heat-insulating wall (13, 14) designed to insulate thermally the outer surface (2a) of the vessel head (2). The heat-insulating wall (13, 14) is leaktight to the fluid coming from the vessel of the reactor in the case of leakage and comprises leaktight connection seals (15, 27) at the outer surface (2a) of the head and at the adaptors (6) serving to delimit a chamber (30) for confinement and for recovery of leakage gases.

Abstract: A nuclear reactor is provided with an emergency cooling water injection device, comprising a vessel through which pass not only the cooling water inlet and outlet pipes under normal operating conditions but also a conduit for injecting pressurized water coming by an emergency reservoir, should a breakage of the primary circuit occur. A thermally insulated duct of the side wall of the vessel, at least at the level of the core, conveys the injected water below the core support plate.

Abstract: The wedging members (15) are introduced between the components (4) at a temperature t0 substantially different from the working temperature ts of the stream generator. The wedging member (15) comprise at least one portion (22) of shape memory alloy having a first configuration at the temperature t0 and a second configuration at the temperature ts, such that the wedging parts (15) have an initial transverse dimension less than the width of the separation spaces between the components (4) at the temperature t0, and a transverse dimension substantially greater than the initial dimension at the temperature ts. The components are wedged automatically at the moment when the installation is brought to the working temperature. The invention is applicable in particular to the anti-vibratory bars disposed in the top part or chignon of a steam generator of a pressurized water nuclear reactor.