Removable platform for working inside a casing of a pressurizer of a pressurized-water nuclear reactor

摘要

A removable platform comprises a chute (14) having a handling and fastening assembly (18, 19, 14a) at one of its ends and a supporting part (14b) in the form of a portion of a cylinder open laterally and extending the tube (14a) substantially in its axial direction, a supporting shaft (16) mounted in articulated manner at the end of the chute, an assembly of supporting arms (15) mounted for pivoting movement about the axis (29) of the supporting shaft (16) and a plurality of plane elements (17) resting on the supporting arms (15) in the unfolded position, to form a work platform substantially over the entire cross- section of the casing (2). The removable platform is introduced into the casing (2) in the folded-up state; the arms (15) form an assembly (30) seated in the chute (14), and the axis (20') at the supporting shaft (16) is substantially perpendicular to the longitudinal direction of the chute (14). The supporting shaft (16) and the arms (15) are subsequently tilted in such a way that the axis (29) of the supporting shaft (16) coincides with the axis (20) of the casing (2). The arms (15) are subsequently unfolded by pivoting about the axis (29) of the supporting shaft (16), and the plane elements (17) are put in place on the supporting arms (15) in the unfolded position.