Control rod devices

Purpose: To provide a control rod drive wherein detaching of the control rod drive and the control rod can be mechanically carried out without using liquid pressure thereby improving reliability and safety of the device and, at the same easily carrying out the operation. Constitution: In the control rod drive of a bwr type reactor, a throat portion is provided in an indexing tube in which the plug of a control rod can be fitted, and a groove is formed in the throat portion in the axial direction thereof. A pin passable through the groove is provided in the plug of the control rod. In such construction, in a case where the connection between the control rod and the operating rod is released, the control rod is pushed up by a latch member mounted on the upper part of operating rod through the plug of the control rod connected to the latch member, and the pin is passed through the groove and pushed up to the upper side of the throat portion, and locked to the throat portion. Then, the latch portion is caused to descend to be disconnected. (Kamimura, K.)