OPTIMIZATION OF LASER-INDUCED BREAKDOWN SPECTROSCOPY PARAMETERS IN A NOVEL MOLTEN SALT AEROSOL SYSTEM

摘要

Pyroprocessing of used nuclear fuel has shown potential as an alternative fuel reprocessing technology to the traditional aqueous technology. Having a clear picture of the actinide, fission product, and rare-earth elements within the salt in realtime is important from processes control, efficiency and material safeguards perspectives. However, measuring the molten salt electrolyte composition within the system is challenging due the high temperature and radiation involved. Laser induced breakdown spectroscopy (LIBS) has been proposed to measure the molten salt composition via a static liquid surface or solid surface approach. These approaches can yield compositional results near real-time; however, concerns with sample homogeneity, splashing, and poor repeatability present significant challenges. A novel molten salt aerosol-LIBS system has been developed to mitigate some of the aforementioned challenges. Here, modifications to the system using a 1-jet nebulizer and sampling chamber are being discussed. Preliminary results demonstrate the advantages and success of the modifications. Experiments were conducted to optimize the spectrometer gate delay and results indicate that the optimal gate delay is greater than 9 us. In addition, the percent relative standard deviations (%RSD) for this system were found to be approximately 7%.