Abstract: The control rod includes an upper absorber section and a lower velocity limiter comprised of a socket, a vane, a transition piece and a set of fins. To adjust the weight of the control rod, lighter and heavier sets of fins, as well as lighter and heavier transition pieces are provided. By suitable selection of the lighter and heavier sets of fins and the lighter and heavier transition pieces, the weight of the velocity limiter can be selectively adjusted in accordance with the weights of differently designed sections to obtain a predetermined control rod weight. Additionally, the heavier transition piece may have material removed therefrom to decrease its weight to provide an infinite adjustment of weight within a predetermined range of weights for the velocity limiter.

Abstract: The control rod includes an upper absorber section and a lower velocity limiter comprised of a socket, a vane, a transition piece and a set of fins. To adjust the weight of the control rod, lighter and heavier sets of fins, as well as lighter and heavier transition pieces are provided. By suitable selection of the lighter and heavier sets of fins and the lighter and heavier transition pieces, the weight of the velocity limiter can be selectively adjusted in accordance with the weights of differently designed sections to obtain a predetermined control rod weight. Additionally, the heavier transition piece may have material removed therefrom to decrease its weight to provide an infinite adjustment of weight within a predetermined range of weights for the velocity limiter.

Abstract: A control rod includes four panels in cruciform section each containing a plurality of absorber tubes. The absorber tubes are mounted between upper and lower mounting structures having generally T-shaped slots opening toward one another. The absorber tubes have generally T-shaped end plugs for reception in the slots. The slots and end plugs are configured to permit limited axial movement of each absorber tube relative to the control rod and to adjacent tubes. The absorber tubes are maintained in tension during all nuclear operations including during a scram.

Abstract: A control rod assembly for a nuclear reactor, wherein a plurality of absorber tubes are arranged and welded in a side-by-side array, the improvement wherein each absorber tube is formed with an elongated slot extending substantially the entire length of the absorber tube on one side of the tube, and with an elongated tab extending substantially the entire length of the absorber tube on a diametrically opposed side of the tube such that, for adjacent absorber tubes, a joint is formed wherein the tab of one tube is located within the slot of the other.

Abstract: A control rod for a nuclear reactor incorporates a plurality of neutron absorber tubes containing neutron absorbing materials. The absorber tubes are substantially rectangular inside and outside, each tube containing at least one axial stack of substantially round neutron absorbing material segments or capsules.

Abstract: A generally cruciform-shaped control rod for a nuclear reactor is formed by vertical stiffeners laterally spaced one from the other and interconnected by horizontal stiffeners at their ends defining discrete compartments in each wing of the cruciform-shaped control rod. Sheathing overlies the stiffeners to seal each of the compartments from its surrounding environment. Neutron-absorbing material, such as boron carbide and/or hafnium tubes, are disposed in each compartment. Each wing is secured to a generally cruciform central tie rod formed of planar plates superposed one over the other alternately at right angles with the outer edges of the plates welded to the inner edges of the wings, affording structural support to the control rod.

Abstract: A neutron-absorber control rod tube includes end plugs welded at opposite ends to the tube with each end plug having a bore opening into the interior of the tube. A hafnium rod is disposed inside the absorber tube and has reduced diameter end portions providing an interference fit with the bores of the end plugs. The end faces of the hafnium rod terminate short of the inner end faces of the bores of the end plugs defining gas pockets therebetween. The interference fits between the bores of the end plugs and hafnium rod, respectively, afford substantial frictional resistance to relative movement of the end plugs and absorber rod, while the gas pockets provide a viscous dampening effect upon relative movement of the end plugs and absorber rod, in response to acceleration or deceleration loads on the structure in an axial direction of the absorber tube and the absorber rod.