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Molten salts are under consideration as the working fluid in thermal power generation. Nitrate molten salts store vast amounts of energy at high temperature and are an efficient energy production medium. Nitrate molten salts are corrosive to structural materials in these applications. Static corrosion studies may neglect the effects of fluid flow on corrosion and flowing test loops can be expensive and complex. A rotating cylinder electrode (RCE) can simulate the effects of fluid flow on the corrosion of structural materials and are more compact and economical then flow loops. We have developed a rotating cylinder electrode apparatus to study the corrosion of structural metals in flowing molten salts using accelerated electrochemical corrosion testing. In this study, we have evaluated the corrosion behavior in molten nitrate salts and used various surface characterization techniques to compare the results from static corrosion tests. Results and analysis of these studies will be presented. 

Advanced nuclear reactors using alkali chloride molten salts are actively being developed for deployment as safer next generation reactors. These reactors operate more efficiently and can enable a more flexible nuclear fuel cycle. These designs require the development of the understanding of corrosion at operational conditions. Static corrosion studies fail to capture the effects of flowing electrolyte on the corrosion in these systems. To simulate the effects of flow, we have designed and commissioned an apparatus for such corrosion studies. This study explored the corrosion of alloys in LiCl-KCl eutectic molten salt. After long-term exposure under simulated flow conditions, corrosions samples were evaluated using gravimetric analysis, scanning electron microscopy and energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy and the results are compared to corrosion under static conditions. Results and analysis of the effects of fluid flow on the corrosion on structural materials will be presented. 

Pyroprocessing is a potential route to close the nuclear fuel cycle. Used nuclear fuel (UNF) is electrolytically reduced from UO2 to U0 at a stainless-steel cathode while oxygen evolution occurs at a platinum anode in a molten LiCl-Li2O environment. Platinum is consumed during this process as a result of the formation and spallation of lithium platinate. To increase the economic viability of pyroprocessing, alternative low-cost, electrochemically efficient materials are needed to replace platinum. In this study, metal-oxide coated 316L stainless streel rods were explored as potential replacements. The characteristics of these coatings in molten LiCl-Li2O was evaluated through electrochemical techniques. The surface chemistry of the coatings was explored through X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and scanning electron microscopy before and after exposure to molten salts to understand the degradation of the coatings. Results detailing the performance of the coatings will be presented.