Abstract: A nuclear reactor, such as advanced pressurized water reactor, with controlled power output includes a reactor core having a cross section in a given plane with a center of area and axes of symmetry passing through the center of area. A multiplicity of control elements are disposed in groups, each having at least one of the control elements. The control elements of each of the groups with more than one control element are joined together. The groups are symmetrical to at least two of the axes of symmetry. Drive mechanisms each move a respective one of the groups of control elements. Each of the control elements has a plurality of control rods. A support structure joins the control rods to one another. Fuel assemblies are disposed in groups. Each of the groups of control elements has a given number of control elements being associated with one of the groups of fuel assemblies having the given number of fuel assemblies.