869,560. Nuclear reactor control rods. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Feb. 12, 1960 [Feb. 26, 1959], No. 6802/59. Class 39(4). A reactor control member comprises an elongated casing 6, a movable member 12 at the bottom of the casing, a lifting cable 5 the tension in which normally holds the member 12 to close the casing, and a mass of particulate neutron absorbers in the casing; if the control member becomes jammed the tension in the cable is relaxed and the neutron absorbers are able to fall out of the casing into the control rod channel. The member 12 carries a shock absorber 16. The channel contains a tube 3 at the bottom of which is a grid which allows passage of coolant but prevents loss of absorber partides; this tube can be discharged from the reactor. The absorber may be boron steel balls. Specifications 813,584, 816,157 and 857,432 are referred to.