Device for measuring clearance around a pin for centering the upper internal equipment of a pressurized water nuclear

Claim 1

Device for measuring clearance around a pin (3) for centering the upper internal equipment of a pressurized water nuclear reactor on the lower internal equipment, placed in the reactor vessel which is open and filled with water, the lower internal equipment comprising the reactor core enclosure to which centering pins (3) are fixed, and the upper internal equipment comprising the upper core plate (1) in which slots (2) corresponding to the centering pins (3) are machined, characterized in that is comprises: a carrier (6) integrally fixed to a pedestal (7) equipped with means (10, 11) intended to cooperate with holes (12) in the upper core plate (1) for fixing the carrier (6) on the upper core plate (1), at least two travellers (15) mounted in the carrier (6) and parallel to the bearing surface of the pedestal (7) which is placed on the upper face of the upper core plate (1), two movable slides mounted on the two travellers (15), each carrying a planar marking plate (31) parallel to the direction of movement of the slides (20) and each equipped with a sensing finger (30) projecting downwards relative to the bearing face of the pedestal (7), resilient means (25) for returning the slides to bring them back towards each other, in the direction of the travellers (15) and mounted within the carrier (6), and a marking assembly carried by the carrier (6) and comprising two styli (33) mounted in guiding carriers (32) directed at right angles to the marking plates (31), each placed facing a marking plate (31) and pushed towards the plate (31) by a resilient means (36), and a control equipment (34) conected to the styli (33) and to a control cable (35) whose end away from the control equipment (34) enables a pull to be applied to separate the styli (33) from the marking plates (31), by compressing each of the pushing means (36), the styli moving to mark the plates (31) when the cable (35) is released.