The potential use of cost-effective carbon anodes, as an alternative to expensive platinum, in the reduction of oxides within LiCl-Li2O molten salt at elevated cell potentials presents a promising avenue. However, this elevated potential gives rise to the generation of a complex mixture of anodic gases, including hazardous and corrosive species such as chlorine (Cl2), oxygen (O2), carbon monoxide (CO), and carbon dioxide (CO2). In this study, we investigate the influence of applied potential and salt composition on the composition of the generated gas mixture. Real-time gas analysis was conducted during the TiO reduction reaction in the molten salt at 650°C using a MAX-300-LG gas analyzer. Simultaneously, electronic signals, including current, potential, and salt composition, were monitored throughout the oxide reduction process. Additionally, XRD investigations were performed to verify the crystal structure of the resulting products. This research provides valuable insights into optimizing carbon anode-based reduction processes for improved efficiency and safety.

Corrosion of copper (Cu) canisters is one of the important factors to ensure the safety of a deep geological repository site. This is because the corrosion of a canister may induce failure of the canister which can lead to a release of radionuclides into the environment. Corrosion of canisters for highlevel wastes is affected by the following multiphysics: thermal-hydraulics, transportation of chemical species, chemical reactions, and interface reactions. This research aimed to develop a multiphysics numerical model for the corrosion of spent nuclear fuel canisters for a deep geological repository in South Korea. The multiphysics model is based on MOOSE (Multiphysics Object-Oriented Simulation Environment) which uses a finite element method. In the multiphysics model, the following multiphysics are coupled and solved together for a deep geological repository design of South Korea: interface redox reactions, porous flow, and heat transport in porous flow. The proposed model was validated with experimental data before being applied to a KAERI reference disposal unit. It was found that the corrosion potential of a Cu canister shows an uneven distribution of corrosion potential along with the surface. In addition, top, bottom, and side surfaces of the canisters show a different lifetime and corrosion potential. Important redox reactions for corrosion are changed along with time from a reduction of O2 and anodic dissolution of Cu by Cl− to sulfidation of Cu and reduction of water. The proposed model will be coupled with some important chemical reactions in engineering buffers and will be the base for the understanding of the behavior of Cu canisters in the KAERI reference disposal unit.

탄소전극과 이온교환막을 결합한 막결합 축전식 탈염(MCDI) 셀을 이용하여 환원전위가 다른 Na+과 Cu2+ 이온 혼합용액에서 Cu2+ 이온의 제거 특성을 연구 하였다. MCDI 셀에 일정한 전류밀도(1.5 mA/cm2)를 공급하면서 탈염을 실시한 결과 Cu2+ 이온은 일정한 제거속도를 유지하였지만 Na+ 이온의 제거량은 시간에 따라 감소하였다. 이는 Cu2+ 이온은 전착반응에 의해, Na+ 이온은 전기흡착 반응에 의해 제거되기 때문인 것으로 판단된다. Cu2+ 이온의 당량비가 0.14, 0.38, 0.50인 혼합용액을 탈염한 결과 제거된 이온 중 Cu2+ 이온의 당량비는 각 각 0.27, 0.60, 0.79로 나타났다. 이를 통해 Cu2+ 이온의 전착반응에 의해 혼합용 액에서 Cu2+ 이온의 제거율을 증가시킬 수 있음을 알 수 있었다.