[en] In a nuclear fuel reprocessing method for supplying nitrogen oxides used for driving out iodine and for oxidizing plutonium, according to the present invention, nitric acid is decomposed in a nitrogen oxide production step to form nitrogen oxides. The nitrogen oxides formed are supplied to the reprocessing step described above. Excess nitric acid recovered from the reprocessing step is recycled to the nitrogen oxide production step. Accordingly, the amount of wastes discharged from the reprocessing step is remarkably reduced. (T.M.)