PNNL

Abstract

This work describes the development of a vacuum compatible microfluidic electrochemical cell (E-cell) for investigating the redox of uranium oxide (UO2). Conducting experiments on bulk amounts of radioactive material is costly and requires shielded hot cell facilities. By using microfluidic techniques, the amount of radioactive materials used in a single test can be significantly reduced, allowing for electrochemical experiments outside of a shielded facility. The paper details several attempts to develop a microfluidic E-cell that uses UO2 as the working electrode and can be used for in situ chemical imaging analysis. The authors discuss the advantages of microfluidic E-cells over traditional electrochemical cells and the challenges of designing a microfluidic E-cell that uses solid material as a working electrode and is compatible with vacuum-based analytical instruments. The paper outlines the different methods proposed for attaching the UO2 electrode under a thin detection window of the E-cell, including Focused Ion Beam Scanning Electron Microscopy lift-out method, Au-coating attachment, and polyvinylidene fluoride (PVDF) binder method. The authors conclude that using PVDF binder method is the most effective approach and demonstrates that particle-based electrodes can provide an effective and low-cost solution for microfluidic electrochemical applications. The in situ microfluidic E-cell design with the integration of a radioactive material working electrode provides a promising and cost-effective approach for investigating spent nuclear fuel via reducing the amount of materials needed for analysis.