Hello, I am working a on a project to improve the thermal properties (heat capacity, thermal conductivity) of heat transfer fluids used in concentrated solar power (CSP). First a suitable base fluid is required, the higher the working temperature the better for thermal efficiency. Most of the work so far is based on carbonate and nitrate salts but most of these break down over 600dC. I recently read a paper titled 'High Temperature Liquid Fluoride Salt Closed Brayton Cycle Solar Power Towers' which attempted to suggest work done on nuclear power plants could be applied to CSP. I would be interested in experimenting with these salts (such as NaF–KF–ZrF4, LiF–NaF–KF etc eutectic mixes) in the lab but some of my colleagues have expressed concerns that fluoride based salts could release fluorine gas. The paper mentions 'Liquid fluoride salts have been injected into water with no violent reactions (steam explosion or chemical reaction)' but does not mention the potential for gas release. High temperature testing would be with small amounts in DSC and TGA. My background is more physics than chemistry so any advice is welcome.