Abstract:
The apparatus comprises a single mast assembly which accomplishes all of the functions which presently require the use of three handling masts, one for fuel assemblies, one for control rods and other long rods, and one for orifice rods. The assembly, in its preferred form, includes a long primary mast secured at its upper end to a handling bridge to depend vertically therefrom, a much shorter working mast vertically movably mounted within the primary mast, and a control rod grapple shank vertically movably mounted within the working mast and of about the same length. The working mast can be lowered onto a fuel assembly and connected to it by gripper latches to lift the fuel assembly and move it to or from the reactor core or other locations, after raising it within the primary mast for protection. The grapple shank can be lowered within the working mast until a grapple at its lower end contacts and connects to the head of a control rod bundle and can then be raised to lift the bundle into the working mast and the working mast into the primary mast for similar transfers. Stops and detents are provided to cause the grapple shank to rise only a short distance within the working mast to house the very short orifice rods and then raise the working mast up within the primary mast.