Nuclear reactor pressure vessel sampling system - with spark erosion unit for taking specimens.

摘要

In a system for electro-erosive complete sampling of nuclear reactor pressure vessels using a central mast, the novelty is that (i) a baseplate (8) is screw mounted onto the main joint (2) of the pressure vessel (1) for fixing a tool head (7) on which are mounted the spark erosion unit, a meter, a television camera, a light and an eroded depth recorder; (ii) a hydraulic unit (9) and a flushing pump (12) are located at the level of the main joint (2); (iii) the erosion device (11) is fixed by a coupling unit to the jib (8) of a positioning system (4), which is installed in the pressure vessel (1) by a conventional central mast (5), and is connected to the tool head (7) by a rack with a connector, a vertical coupling rod (10), an intermediate piece and a connector coupling rod; and (iv) for additional erosion monitoring and precise height adjustment of the erosion device (11), an illuminated underwater camera is provided and, at ground level, a working machine with an operating desk (13), a pulse generator unit (14) and a monitoring desk (15), consisting of monitors, an oscillograph and a recorder, is installed. USE/ADVANTAGE - The sampling system is used in pressure vessel examination, pref. before and after thermal repair. It allows taking of complete samples to determine the effects of thermal repair and/or the brittle fracture safety of the vessel, so that an indication of remaining service life is obtd.