METODO Y SU CORRESPONDIENTE APARATO DE SOPORTE E POSICIONA- MIENTO DE HERRAMIENTAS ACCIONADO Y CONTROLADO A DISTANCIA Y-DESTINADO A ESTAR MONTADO DEBAJO DE LA PLACA.

摘要

A remotely operated and monitored tool support and positioning apparatus for retubing a steam generator adapted for mounting below the tubesheet of a vertically standing nuclear steam generator. A tool holding arm comprises a platform with an opening and a rotatable plate (50) supported thereon with a vertical hollow shaft (48) extending downwardly through the opening (28). The lower surface of said plate (50) has a plurality of cavities (58) evenly spaced along a circle whose center is the axis of rotation of said plate (50), and an indexing means including a movable pin (62) is associated with said platform (24) so as to be received in said cavities (58), the pin (62) being movable between a fully retracted position permitting rotation of said plate (50) and a fully protruding position for indexed seating within one of said cavities (58) to position said plate (50) in an exact angular position. This arrangement facilitates remote positioning of a tool in limited and radioactive area of a nuclear steam generator heat for repair work.