Three-coordinate positioning apparatus for the inspection and maintenance of nuclear reactor components

摘要

In the upper internals storage pit of a containment building housing a pressurized water nuclear reactor, there is installed a three-coordinate positioning apparatus which has a frame-like, horizontally oriented base track enclosing an area designed to be occupied by any of the control rod clusters when lowered from the upper internals supported in the storage pit; a mechanism for supporting and vertically displacing the base track in the storage pit; a traversing track supported on the base track for back-and-forth displacement in a first horizontal direction; a mechanism for moving the traversing track in the first horizontal direction; and a carriage supported on the traversing track for back-and-forth displacements in a second horizontal direction perpendicular to the first horizontal direction. The carriage is adapted to receive thereon inspection equipment. The positioning apparatus further has a mechanism for moving the carriage in the second horizontal direction; and an access track situated in the storage pit externally of and horizontally spaced from the area enclosed by the base track. The access track is arranged to be alignable by the traversing track to provide transferability of the carriage from the traversing track to the access track and conversely. The carriage is directly accessible from an operating floor above the storage pit when the carriage is on the access track.