| 摘要 |
The invention relates to an arrangement for determining play between a driving nut 2 and a driving device screw 3 for a control rod in a nuclear reactor. The arrangement comprises a first sensor 6 for sensing the mechanical end position of the driving nut 2 for movement along the driving device screw 3. According to the invention, a cam wheel 28 with a number of cams around the circumference is arranged so as to rotate with the driving device screw 3 and act on a second inductive sensor 29. In this connection, each induced pulse corresponds to a certain angular rotation of the driving device screw 3. The second sensor 29 interacts with a pulse counter, and the first sensor 6 is arranged so as, when the driving nut 2 reaches its mechanical end position along the driving device screw 3, to give via a measurement member a starting signal for counting the number of pulses generated by the cam wheel 28 in the second sensor 29 on rotation of the cam wheel 28 with the driving device screw 3 from said end position to the point at which mechanical rotation of the driving device screw 3 stops. <IMAGE> |
