 Beryllium is also used at the Joint European Torus nuclear @-@ fusion research laboratory , and it will be used in the more advanced <unk> to condition the components which face the plasma . Beryllium has also been proposed as a cladding material for nuclear fuel rods , because of its good combination of mechanical , chemical , and nuclear properties . Beryllium fluoride is one of the constituent salts of the eutectic salt mixture FLiBe , which is used as a solvent , moderator and coolant in many hypothetical molten salt reactor designs , including the liquid fluoride thorium reactor ( <unk> ) . 
