Patent Number: 039309380
Section: abstract

In a nuclear reactor of the BWR type having finger control rods mounted in guide tubes and having a member movable upwardly to push the control rods into the guide tubes, the control rods are connected to this member by a joint such as a bayonet joint releasable by turning of the control rods about their longitudinal axis. On the upper ends of each control rod is slidably mounted a sleeve which is spring-pressed downwardly. This sleeve is non-rotatable with respect to the control rod. The sleeve has either a square lower end slidable within a square tube or has projections at its lower end in a round tube having ribs running longitudinally thereof. The arrangement is such that when the support is in its uppermost position the control rods project above the fuel assembly and the sleeve can be raised against the spring action out of the upper ends of the tubes so as to permit turning of the rods to release them for removal.