Nuclear fuel assembly handling apparatus
View Patent ↗A fuel assembly handling tool that can be lowered onto the top nozzle of a fuel assembly, positively latch the top nozzle, unlatch from the top nozzle, and be raised off the top nozzle of the fuel assembly. The tool head, that interfaces with the top nozzle has load bearing grippers that latch onto the fuel assembly, that are located in a storage position up within the tool while the tool is lowered onto the fuel assembly. The gripper fingers are then lowered into position during the latching process, and are raised back to the storage position during the unlatching process. In the storage position, the gripping fingers are spaced above the fuel assembly top nozzle when the tool head is resting on the nozzle.
1. A fuel assembly handling tool comprising:
a bail configured to be connected to a crane or other hoist;
a bail plate connected to the bail as to be freely supported by the bail;
a tool body freely supported at an upper end from the bail plate and extending between the bail plate and a lower end with the length between the upper and lower ends being gauged to access a top nozzle of a fuel assembly; and
a tool head connected to the lower end of the tool body and sized to house a gripper assembly having a plurality of radially outwardly extending hooks in a withdrawn position so that the radially outwardly extending hooks are above and out of contact with the top nozzle of the fuel assembly when the tool head contacts or otherwise rests on the top nozzle, the gripper assembly being operable through an actuator to extend the plurality of radially outwardly extending hooks downward below its withdrawn position over a selected travel path that moves the hooks straight downward to an extended position where the hooks are pivoted outward during a last segment of downward extension to grip a portion of the top nozzle of the fuel assembly to support the fuel assembly as the crane or other hoist lifts the bail, with the gripper assembly being operable to reverse the selected travel path under the control of an operator when the fuel assembly is to be released, wherein the hooks for gripping the top nozzle of the fuel assembly have a laterally extending pin projecting from an upper end portion and the gripper assembly further includes:
a carrier connected to the actuator, being raised and lowered by the actuator and pivotally connected to an upper end of the pin; and
a cam slot on the tool head in which the laterally projecting pin on the upper end portion of the hook rides, the hook pivoting and raising or lowering as the carrier is raised or lowered by the actuator, wherein the pin riding in the cam slot first lowers the hook and then in a lower portion of the pin's travel in the cam slot the pin pivots the hook as the actuator is lowered.
2. The fuel assembly handling tool of claim 1 wherein the actuator is accessible from the bail plate and operable to extend or withdraw the gripper assembly to the extended or withdrawn position.
3. The fuel assembly handling tool of claim 2 wherein the gripper assembly is moved to the withdrawn position or the extended position by respectively raising or lowering the actuator in a linear motion.
4. The fuel assembly handling tool of claim 3 wherein the gripper assembly fully grips the fuel assembly as the actuator is lowered.
5. The fuel assembly handling tool of claim 2 wherein the gripper assembly positively locks in the withdrawn position and in the extended position.
6. The fuel assembly handling tool of claim 1 including guide pins extending down from the tool head for aligning the tool head with the fuel assembly top nozzle.