Patent Number: 047479957
Section: description

MODE OF OPERATION For the shearing of the BWR Control Rod and more exactly for the removal of the velocity limiter end, the entire control rod is held by a crane or similar apparatus at the handle #13. The assembly is then lowered into the shearing apparatus until it sits on the turntable #16. It is rotated by the handle by the operator until the #17 wheel like protrusions fall into the slots provided for them in the rotary device. It should be noted that the rotating device is not a necessity for operation of the system, as the control rod could be repositioned manually, however because this work takes place at the bottom of a fuel storage pool at least 30 ft. in depth in water, it is envisioned as being a more practical way to position for the second cut. Once the control rod is in position, the shearing heads (#18, #19 and #20) are advanced forward in position to shear the fins. FIG. 1 and FIG. 2 represent these #19 cylinders as being in horizontal position. They can however also be mounted vertically and work via a fulcrum to save space. The cylinders #19 are foreseen with holding valves which maintain the the pressure and prevent the shear heads from retracting while under reverse pressure. The shear blades are then activated. The fins are sheared when shear heads are retracted and the #14 cylinder is activated rotating the control rod by 90.degree. and the procedure is repeated.