Patent Number: 
Section: claims

1. An apparatus for controlling a control rod of a nuclear reactor of a nuclear power plant, wherein the control rod is configured to be inserted into or withdrawn from the nuclear reactor, the apparatus comprising:a control rod, wherein the control rod includes recesses;a first controller operable to output a signal to insert or withdraw the control rod;a mechanical portion configured to perform insertion or withdrawal of the control rod in response to the signal output by the first controller, the mechanical portion comprising a latch engagement portion disposed at an upper end of the control rod, a stop latch electromechanically moveable to restrain the control rod by an engagement with the latch engagement portion, a moving latch electromechanically moveable to be fixed to the latch engagement portion, and a lift coil operable to insert or withdraw the control rod by lifting or lowering the moving latch fixed to the latch engagement portion;a detector operable to detect a position or a speed of the control rod when the control rod is being inserted or withdrawn by the mechanical portion; anda brake configured to stop the control rod by force,wherein the brake includes a stopper configured to be inserted into a recess of the recesses comprising a first recess, and wherein the stopper comprises an inclined surface; anda second controller operable to separately control the brake independent of the first controller,wherein the second controller is configured to operate the brake in response to a brake signal being received from the detector. 2. The apparatus of claim 1, wherein the brake further comprises:a second recess disposed on an external wall,wherein the stopper is movable from an internal portion of the second recess to an internal portion of the first recess to stop the withdrawal of the control rod by force. 3. The apparatus of claim 2, wherein the stopper comprises a spring or a hydraulic device on an end, and a roller on another end. 4. The apparatus of claim 3, wherein the stopper is fixed in the second recess while the spring or the hydraulic device is compressed, and when a pressure of the spring or the hydraulic device is released, the stopper turns such that a side surface of the stopper is in contact with a surface of the second recess, and another side surface of the stopper is in contact with a surface of the first recess. 5. The apparatus of claim 3, wherein the roller of the stopper is pushed down by the control rod in an inserting direction of the control rod, and the stopper is fixed in the second recess by an electromagnetic interaction. 6. The apparatus of claim 3, wherein the inclined surface is disposed at a position corresponding to the first recess,wherein a second surface of the stopper is fixed to the second recess by the spring or the hydraulic device, and the roller is disposed on a bottom surface of the stopper. 7. The apparatus of claim 3, wherein the stopper is fixed in the second recess while the spring or the hydraulic device is compressed, and when a pressure of the spring or the hydraulic device is released, the stopper protrudes in a direction of the control rod such that a bottom surface of the stopper is in contact with a surface of the first recess. 8. The apparatus of claim 6, wherein the stopper is pushed in a direction of the second recess by the control rod, and fixed in the second recess by an electromagnetic interaction when the control rod is inserted to be in contact with the inclined surface of the stopper. 9. The apparatus of claim 2, wherein a plurality of first recesses is formed in the control rod at regular intervals.