The development of the Sodium-cooled Fast Reactor, one of the Generation-IV nuclear power reactors that is being developed to continue the sustainable development of nuclear power utilization, is important. To increase the yield of uranium in the fabrication of metal fuel slugs, U-10Zr and U-10Zr-RE fuel metal slugs were fabricated using fuel scraps to maximize the utilization of the nuclear fuel materials and minimize the amount of radioactive waste. Thus, recycled metal fuel slugs were fabricated using heel residues to increase the recovery of uranium and decrease the radiation active waste during the fabrication process of the metallic fuel slug. There are two necessary characteristics of a metallic fuel slug. One is a sound fabrication, and the other is a suitable mixture content(C + N + O + Si < 2,000ppm).
The metallic fuel scraps were treated applying the chemical method and mechanical method to remove any impurities on the fuel scraps, such as the oxide layer. In this study, recycled metal fuel slugs were fabricated using fuel scraps such as heel residue and butts of metallic fuel slugs. To examine the soundness of recycled metal fuel slugs, the density of the metal fuel slugs was measured using an Archimedean immersion method. The alloy compositions and impurities of washed metal fuel scraps were investigated using ICP-AES. The microstructure and composition of heel were analyzed using SEM/EDS. The XRD patterns of the recycled metallic fuel slugs were similar to the results of the metallic fuel slugs fabricated using pure metal materials. All quality evaluation for the recycled metallic fuel slugs confirmed that the specification requirements were met.
The feasibility of this recycling technology was thus demonstrated by the results of the present study. This developed technology is very cost-efficient because not only can it be applied to decrease the radiation active waste by up to 10%, but it can also increase the uranium utilization.