Patent ID: 7412021

Claim:
A gray rod assembly for a rod control assembly of a nuclear reactor, said nuclear reactor including a number of fuel assemblies each having a plurality of elongated nuclear fuel rods supported in an organized array by a number of substantially transverse support grids, and a plurality of guide thimbles disposed through said support grids and along said fuel rods, said rod control assembly including a spider assembly having a plurality of radially extending flukes and being structured to move each gray rod assembly within one of said guide thimbles in order to control the rate of power produced by said nuclear reactor, said gray rod assembly comprising: an elongated tubular member having a first end, a second end, an outer diameter, a length, and a wall thickness; a first end plug coupled to the first end of said elongated tubular member, and being structured to facilitate insertion of said elongated tubular member into one of said guide thimbles of said fuel assembly; a second end plug coupled to the second end of said elongated tubular member, and being structured to be coupled to one of said radially extending flukes of said spider assembly of said rod control assembly; only one single solid neutron-absorber element disposed within said elongated tubular member generally toward the first end thereof, said neutron absorber element having a diameter which is substantially less than the diameter of said elongated tubular member, and a length which is shorter than the length of the elongated tubular member, in order to minimize the exposed surface area of said neutron-absorber element to radiation when said tubular member is inserted into said thimble; and only one single support tube structured to surround said neutron-absorber element within said elongated tubular member, said neutron-absorber element centrally disposed within said support tube, said support tube having a wall thickness and being disposed between said neutron-absorber element and said elongated tubular member, and being structured to resist swelling of said neutron-absorber element, wherein said wall thickness of said support tube is greater than said wall thickness of said elongated tubular member, and wherein said support tube comprises a single continuous piece of material.