Abstract: An apparatus for concentrating and solidifying a salt solution includes a vessel for containing the salt solution having an exposed surface, the vessel having a generally open upper portion, a cover for sealing the generally open upper portion of the vessel and having a generally hood shaped portion, the cover including at least one inlet conduit for admitting the salt solution to the vessel and a discharge conduit for vapor, and a magnetron for generating microwaves for heating the solution in the vessel. A microwave waveguide is disposed between the magnetron and the vessel and incorporates the cover, for directing microwaves from the magnetron into the vessel, the waveguide transitioning within the cover from the generally hood shaped portion into a horn having a variable cross-section and/or variable vertical spacing with respect to the vessel. This structure enables microwaves to be radiated directly onto the exposed surface of the salt solution in the vessel.

Abstract: There is provided a furnace for incinerating nuclear fission and/or fertile material waste, particularly plutonium and/or uranium containing organic waste by pyrohydrolysis with steam or burning with air oxyen in safe geometry, said furnace comprising in combination a stationary cylindrical outer jacket having a funnel shape at the bottom thereof, a rotatable inner cylinder likewise terminating at the bottom in a funnel shape whose diameter is so regulated that the interval between the outer jacket and the inner cylinder guarantees a safe layer thickness and scrapers which are disposed on the inner surface of the outer jacket and the outer surface of the inner cylinder.