Underwater milling machine system for core barrel repair

摘要

A machining system for performing heavy duty milling and other repair operations under water is disclosed herein which is particularly useful in performing repair and maintenance operations in the core barrels of nuclear reactors. The machining system generally comprises a platform, a machining device which is detachably connectable to the platform which includes a drive motor and cutter necessary to effect the repair or maintenance operation, and a triaxial adjustment mechanism which permits the machine cutter to be precisely positioned at any desired location within the core barrel. The platform has a guide mechanism which includes both a rough and a fine guide means which precisely positions the machining device with respect to the platform when it is lowered thereon. A hydraulically operated lock remotely and detachably secures the machining device into position on the platform after the guide mechanism has properly positioned it. The platform is advantageously designed to be secured onto a component within the core barrel having a known and precise alignment with respect to the other core barrel components, such as the support lugs of the thermal shield, which in turn provides a mechanical reference point for the machine cutter attached to the platform.