Pronunciation: [flˈa͡ɪb] (IPA) 
The word "flibe" is spelled with the letters F, L, I, B, and E. Its pronunciation can be represented using IPA phonetic transcription as [flaɪb]. This means that the first sound is like the "fl" in "flame," followed by a long "i" sound like the "i" in "dine," and then a "b" sound like in "bat." The final sound is a vowel, which can be pronounced like the "e" in "pet" or the "a" in "pan," depending on the speaker's accent.
Flibe, derived from the acronym FLiBe (fluoride–lithium–beryllium), is a specialized type of molten salt consisting of a mixture primarily composed of lithium fluoride (LiF) and beryllium fluoride (BeF₂). This unique compound finds extensive applications in various nuclear reactor designs, particularly as a coolant and as a medium for fuel transport.
In a broader sense, flibe refers to any mixture of lithium and beryllium fluorides, but the term often specifically refers to the specific FLiBe composition employed in liquid fluoride thorium reactors (LFTRs). LFTRs are a type of molten salt reactor that utilize the radioactive isotope thorium-232 (Th-232) as fuel, with flibe functioning as both the coolant and the medium to dissolve and circulate the thorium fuel.
Due to its exceptional properties, flibe has gained popularity in nuclear engineering as a promising coolant and heat transfer fluid. Its high boiling point, low vapor pressure, good heat conductivity, and excellent neutron moderation capability make it ideal for thermal reactors. Moreover, FLiBe can effectively dissolve and distribute fissile or fertile materials within the fuel salts, offering enhanced fuel processing flexibility.
Furthermore, flibe's excellent chemical stability, along with its lower operating pressures compared to water-based coolants, promotes reactor safety. It can handle high radiation and possess low chemical reactivity with the reactor materials, thus reducing the risk of corrosion and radioactive contamination.
In summary, flibe is a specialized mixture of lithium fluoride and beryllium fluoride that finds application as a coolant and fuel medium in thorium-based molten salt reactors. It exhibits desirable properties such as high heat transfer capacity, good chemical stability, and enhanced fuel processing capabilities,
The word "flibe" is a portmanteau of "fluoride" and "lithium-beryllium", referring to a specific type of molten salt mixture used as a coolant in certain advanced nuclear reactors. The term was coined by Dr. Eugene Booth in the late 1950s when he was working at Oak Ridge National Laboratory in the United States. The mixture consists of lithium fluoride (LiF) and beryllium fluoride (BeF₂), hence the combination of these two elements to create the word "flibe".
