FLiBe

FLiBe is a high-temperature molten salt composed primarily of lithium fluoride (LiF) and beryllium fluoride (BeF2). It is widely studied and considered a promising coolant and material in emerging nuclear reactor technologies, particularly in liquid fluoride thorium reactors (LFTRs) and other molten salt reactor concepts.

The typical composition of FLiBe is around 66% LiF and 34% BeF2 by mole, which provides excellent thermal conductivity, chemical stability, and a high boiling point exceeding 1400°C. It is known for its ability to operate at high temperatures without pressurization, enhancing safety and efficiency by enabling higher thermal efficiencies.

One of the key advantages of FLiBe is its low neutron absorption cross-section, making it suitable for use as a neutron moderator and coolant in nuclear reactors that utilize thorium or uranium fuels. Additionally, beryllium fluoride acts as a neutron reflector, improving reactor performance.

FLiBe is chemically stable under operating conditions, but it is highly corrosive to many metals, necessitating the use of corrosion-resistant materials such as nickel-based alloys. Its use entails handling challenges and safety considerations, particularly due to the toxicity of beryllium compounds.

Research and development efforts are ongoing to optimize FLiBe-based systems, aiming for safer, more efficient, and sustainable nuclear energy solutions. Its potential applications extend beyond nuclear reactors, including in advanced energy storage and thermodynamic applications.

Overall, FLiBe’s unique physical and chemical properties make it a central focus in the development of next-generation nuclear technologies.