Japanese fusion energy company Kyoto Fusioneering (KF) has signed an agreement with industrial company NGK Corporation to develop and commercialise Flibe required for fusion plants to extract heat from plasma.

Flibe is a molten salt made from lithium fluoride and beryllium fluoride and is seen as a method to extract heat away from a reactor and breed the tritium fuel needed to sustain a fusion reaction.

It is essentially both a nuclear reactor coolant and a solvent for fertile or fissile materials. The companies will produce, refine, and test the molten salt. They will also build the circulation systems needed to use it in commercial fusion reactors.

Flibe was first used in the 1960s at the Oak Ridge National Laboratory in Tennessee. It is prized in advanced nuclear reactors for its safety, high thermal capacity and low-pressure operation.