[en] The OREOX(Oxidation and REduction of OXide fuel) process has been performed to fabricate dry recycling(DUPIC ; Direct Use of spent PWR fuel In CANDU reactor) nuclear fuel pellets by using spent PWR fuel. Generally, sinterable DUPIC powder has been manufactured from spent PWR fuel pellets by the 3 cycles of oxidation and reduction treatment. The OREOX process is one of the most important processes for DUPIC pellet fabrication. A lot of time more than 37 hours as well as a lot of reaction gas is required to perform 3 cycles of OREOX treatments. In this experiment, 1 cycle OREOX process was adopted to improve the powdering process of DUPIC pellet manufacturing processes. As a result of experiment, the densities of pellets sintered at 1800 .deg. C for 10 hours ranged from 10.15 to 10.22 g/cm³(93.8∼94.5 % of T.D.). The pellets were sintered again to increase the sintered density. The sintered densities of pellets re-sintered at 1850 .deg. C for 7 hours ranged from 10.27 to 10.33 g/cm³(94.9∼ 95.5 % of T.D)