Abstract: According to one embodiment of the present invention, the oxygen gas is introduced into a horizontal, unitary and totally-closed furnace shell, and nuclear fuel to be reprocessed is charged onto an oxidation and separation plate which is horizontally disposed for vibration within the furnace shell along the axis, so that the nuclear fuel may be reprocessed by oxidation in the oxygen atmosphere while the fuel is vibrated and transported on the oxidation and separation plate and the reprocessed nuclear fuel in the form of particles may be discharged. At the same time released volatile fission products from the pulverized fuel are isolated by means of a vacuum blower. According to another embodiment of the present invention, a reduction furnace which is substantially similar in construction to the oxidation furnace described above except that a reducing gas is supplied by an independent source.