A fuel assembly for a nuclear reactor, said fuel assembly comprising: a plurality of elongated nuclear fuel rods each having an extended axial length; a number of substantially transverse support grids spaced along the axial length of said fuel rods in order to hold said fuel rods in an organized array; a plurality of guide thimbles disposed through said support grids and along said fuel rods and a gray rod control assembly including a spider assembly having a plurality of radially extending flukes and a plurality of gray rod assemblies coupled to said flukes, said gray rod control assembly being structured to move each of said gray rod assemblies within one of said guide thimbles in order to control the rate of power produced by said nuclear reactor, wherein each of said gray rod assemblies comprises: an elongated tubular member having a first end, a second end, an outer diameter, and a length, a first end plug coupled to the first end of said elongated tubular member, said first end plug being tapered in order to facilitate insertion of said elongated tubular member into one of said guide thimbles of said fuel assembly, a second end plug coupled at one end to the second end of said elongated tubular member, and at the other end to one of said radially extending flukes of said spider assembly, a neutron-absorber disposed within said elongated tubular member generally toward the first end thereof, said neutron absorber comprising a substantially pure silver absorber material and having a diameter which is substantially less than the diameter of said elongated tubular member, and a length which is substantially shorter than the length of the elongated tubular member, and a support tube disposed between said neutron-absorber and said elongated tubular member thereby encapsulating said neutron-absorber within said tubular member in order to resist swelling of said absorber. a plurality of elongated nuclear fuel rods each having an extended axial length; a number of substantially transverse support grids spaced along the axial length of said fuel rods in order to hold said fuel rods in an organized array; a plurality of guide thimbles disposed through said support grids and along said fuel rods and a gray rod control assembly including a spider assembly having a plurality of radially extending flukes and a plurality of gray rod assemblies coupled to said flukes, said gray rod control assembly being structured to move each of said gray rod assemblies within one of said guide thimbles in order to control the rate of power produced by said nuclear reactor, wherein each of said gray rod assemblies comprises: an elongated tubular member having a first end, a second end, an outer diameter, and a length, a first end plug coupled to the first end of said elongated tubular member, said first end plug being tapered in order to facilitate insertion of said elongated tubular member into one of said guide thimbles of said fuel assembly, a second end plug coupled at one end to the second end of said elongated tubular member, and at the other end to one of said radially extending flukes of said spider assembly, a neutron-absorber disposed within said elongated tubular member generally toward the first end thereof, said neutron absorber comprising a substantially pure silver absorber material and having a diameter which is substantially less than the diameter of said elongated tubular member, and a length which is substantially shorter than the length of the elongated tubular member, and a support tube disposed between said neutron-absorber and said elongated tubular member thereby encapsulating said neutron-absorber within said tubular member in order to resist swelling of said absorber. an elongated tubular member having a first end, a second end, an outer diameter, and a length, a first end plug coupled to the first end of said elongated tubular member, said first end plug being tapered in order to facilitate insertion of said elongated tubular member into one of said guide thimbles of said fuel assembly, a second end plug coupled at one end to the second end of said elongated tubular member, and at the other end to one of said radially extending flukes of said spider assembly, a neutron-absorber disposed within said elongated tubular member generally toward the first end thereof, said neutron absorber comprising a substantially pure silver absorber material and having a diameter which is substantially less than the diameter of said elongated tubular member, and a length which is substantially shorter than the length of the elongated tubular member, and a support tube disposed between said neutron-absorber and said elongated tubular member thereby encapsulating said neutron-absorber within said tubular member in order to resist swelling of said absorber.