Moving coil type control rod drive mechanism

A new type of control rod drive mechanism was developed for use in research reactors. This mechanism utilizes a moving coil type actuator, and there is no leakage of reactor coolant, which contributes to a very high degree of safety. In addition, this mechanism is much more reliable as compared with the conventional one because of the simplicity in its construction. Various tests were performed on the new full scale mechanism. The results revealed the position accuracy of the control rod to be within 0.3 mm and the aggregate travel distance of the r od was confirmed to be in excess of 10000 meters. (author)