Control rod in hydrogen-cooled vessel reactor

The invention relates to the nuclear technology, especially to facilities in the control and protective system of hydrogen-cooled vessel reactors, and can be used among the adjusting mechanisms realized in the form o single rods, either signle or integrated to an assembly. The control rod includes an envelope in which is mounted the neutron absorption tower comprised of two parts, of which one ismade of a material reacting with neutrons (n.'alpha'), for example boron carbide. The other part, inserted into the active portion of the first part of the tower, is of a length determined by a mathematical expression comprising the length of the neutron absorption tower as well as the efficiency values of the control rods with various parameters. The length of that part made of a dysprosium-based material, determined by the above-mentioned mathematical expression, permits to manufacture the rod with a maximum mass, taking into accountthe change in its absorbing properties resulting from an increase in the specific share of the dysprosium-based material, the density of which is clearly lower than that of boron carbide.