Patent Number: 6,309,147

Title: Underwater remote drilling tool and methods

Abstract: A remotely operated drilling tool is configured to produce holes in a core shroud support plate inside of a nuclear reactor vessel. The tool includes a support base that is securely mounted directly above the location where the hole will be formed. In a first operation, a drilling tool is secured to the support base and drills a hole through about 90% of the shroud support plate. The drilling tool includes chip capturing structure to prevent chip created by the machining process from contaminating the water in the reactor vessel. After about 90% of the hole is drilled with the drilling tool, an EDM tool is secured to the support base to machine the remainder of the hole using an EDM process. The EDM tool includes structure for machining the remainder of the hole, removing the slug from the hole, and performing a spotface on the underside of the shroud support plate. The underwater drilling tool is capable of producing high quality holes faster and more efficiently than the current EDM process, while maintaining control of all foreign material, minimizing the deleterious effects on the material being drilled, and reducing the risk associated with poor tool reliability and breakage.

Inventors: Matsumoto; Jack T. (Sunnyvale, CA), Kazirskis; Benedict (Barto, PA), Pence; Vernon W. (San Jose, CA), Kasik; James F. (San Jose, CA)

Assignee: General Electric Company

International Classification: G21C 5/10 (20060101); G21C 5/00 (20060101); G21C 19/00 (20060101); B23B 047/34 ()

Expiration Date: 10/30/2018