Abstract: A replacement rod for insertion into a nuclear fuel assembly to replace a fuel rod containing a neutron absorbing, fissile fuel, includes Hafnium sufficient to substantially replace the neutron absorption capacity of the fuel rod. The replacement rod also includes a non-fissile second material that is commonly used for structures in nuclear fuel assemblies. The second material is preferably selected from the group consisting of a stainless steel, a zirconium alloy and zirconium. In one embodiment, the Hafnium is fabricated into a cylindrically-shaped rodlet, or core, and the second material is fabricated into an annulus around the core. Alternatively, the Hafnium and the second material are each distributed about uniformly throughout a cylindrical volume of the replacement rod. Refurbishing nuclear fuel assemblies by replacing damaged fuel rods with replacement rods according to the invention obtains an improved peaking factor over prior art methods.