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.