 Being a commercial service, it normally applies to DERV (road vehicle diesel fuel) rather than petrol (gasoline).At the former nuclear research facility at Dounreay in the far north of Scotland, the word bowser is used to describe various moveable (but not wheeled) vessels that contain alkali metals (sodium or NaK), protected from oxidation by an inert gas.The word may also have been in use at the Atomic Energy Authority's (now UKAEA's) southern sites.