Abstract: A fixing device for detachably fixing a heating element to a sleeve welded to the body of the pressurizer of a nuclear reactor comprises an assembly of members with a symmetry of revolution, the axes of the members being coaxial with the heating element. The members comprise a gasket-carrying collar made integral with the heating rod and which bears on the outer face of a shoulder on the sleeve, a two-part ring which bears on the inner face of the shoulder on the sleeve, a screw-threaded nut and a screw-threaded tubular collar which are threaded together and bear respectively on the collar and the ring. The nut is provided with an opening for water leaking from the pressurizer and a zone of reduced thickness along which the nut can be cut in the event of seizure of the nut and tubular collar.

Abstract: Apparatus for removing residual stresses produced in a tube by seating the tube in a bore in a tube plate, the tube having one end flush with one face of the tube and extending from the other face and being seated in the plate by expanding and rolling the tube at the level of the plate up to a transition zone in the region of emergence of the tube from the other face of the plate, the apparatus comprising an elongate tubular element having a cage at one end provided with longitudinal recesses housing radially movable wheels and a control rod which is axially movable in the element to cause the wheels to project radially from the cage and rotatable to rotate the wheels, the portion of the rod in contact with the wheels being conical and the axes of the wheels being inclined to the axis of the tubular element, an adjustable stop for precisely positioning the wheel cage at the level of the transition zone of the tube, and control means for causing axial movement of the rod to bring the wheels into contact with t