Method for shielded relocation of a nuclear component

A method for relocating a nuclear plant component with a machine, the machine comprising:

• a bridge assembly for positioning the machine over the nuclear plant component to be moved;
• a stationary mast supported from the bridge assembly at a first end and extending down from the bridge assembly in a direction of the nuclear plant component;
• a moveable mast, telescopingly nested within the stationary mast and configured to extend from the stationary mast and retract within the stationary mast under the control of an operator;
• a mast shield canister having
• an axially extending central opening through which the moveable mast can extend, the mast shield canister having an upper end portion and a lower end portion, with
• a first stop
• on the upper end portion of the mast shield canister and/or
• on a lower end of the moveable mast preventing the lower end of the moveable mast from withdrawing out of the upper end portion of the mast shield canister and
• a second stop
• on either or both of
• the stationary mast and
• the mast shield canister
• that prevents the mast shield canister from moving more than a preselected distance from the stationary mast,
• the moveable mast is configured to supportingly carry the mast shield canister the preselected distance, and
• while the second stop prevents the mast shield canister from moving more than the preselected distance, the lower end of the moveable mast is axially moveable relative to the mast shield canister,
• the mast shield canister being sized to fit over substantially the full length of the nuclear plant component;
• and
• a gripper assembly
• supported at a lower end of the moveable mast and
• configured to grip the nuclear plant component through the lower end portion of the mast shield canister;
• the method comprising:
• moving the bridge assembly to position the machine stationary mast over the nuclear plant component to be relocate,
• with the gripper assembly aligned with the nuclear plant component;
• moving the moveable mast downward the preselected distance with the mast shield canister suspended below the gripper, supported by the moveable mast;
• supporting the lower end portion of the mast shield canister above the nuclear plant component with the stationary mast once the moveable mast moved downward the preselected distance,
• with the nuclear plant component in line with the central opening through which the moveable mast can extend;
• lowering the moveable mast through the central opening;
• engaging the gripper assembly on a top surface of the nuclear plant component;
• raising the moveable mast to withdraw the moveable mast and the nuclear plant component upward within the central opening;
• and
• moving the bridge assembly to position the nuclear plant component at a new location.