ABSTRAKPROSES SIKLUS REDUKSI (U3O8 + 18 HASIL FISI) UNTUK BAHAN BAKAR DUPIC. Telahdilakukan proses reduksi ke-1 bahan bakar nuklir yaitu (U3O8 + 18 hasil fisi) di dalam tungkureduksi yang dialiri gas hidrogen pada temperatur yang bervariasi dari 600 – 900 oC selama 3jam. Hasil reduksi berupa serbuk (UO2 + 18 hasil fisi) yang kemudian ditentukan densitas curah,ketuk dan sejati serta rasio O/U dan dipelajari pula efek penggerusan serbuk. Serbuk yang tidakmengalami penggerusan, mempunyai densitas yang lebih kecil dibandingkan dengan serbukyang mengalami penggerusan sehingga penentuan densitas dilakukan melalui tahappenggerusan terlebih dahulu. Besarnya temperatur di atas mempengaruhi densitas yangdiperoleh, semakin tinggi temperatur, semakin tinggi pula densitas serbuk, sedangkan rasio O/Umendekati 2. Setelah diperoleh serbuk (UO2 + 18 hasil fisi) dari hasil reduksi ke-1, maka serbuktersebut dioksidasi pada temperatur 500 oC selama 2 jam hingga diperoleh lagi serbuk (U3O8 + 18hasil fisi) yang merupakan bahan untuk proses reduksi ke-2. Proses reduksi ke-2 dilakukansebagaimana proses reduksi ke-1, demikian diulangi sampai pengulangan (siklus) ke-4. Hasilproses reduksi berupa serbuk (UO2 + 18 hasil fisi) yang dikarakterisasi densitas dan rasio O/U.Proses pengulangan reduksi tersebut memperbesar densitas serbuk dan rasio O/U. Daripercobaan yang dilakukan diperoleh hasil kondisi proses yang relatif baik yaitu pada siklus yangke-3, dan temperatur proses reduksi 800 oC dengan waktu pemanasan selama 3 jam. Padakondisi tersebut diperoleh densitas curah, ketuk dan sejati masing-masing 2,4594; 3,2096 dan10,2866 g/cm3 (93,77% TD) serta rasio O/U sebesar 2,0192.Kata kunci: Siklus reduksi, UO2, U3O8, hasil fisi, bahan bakar DUPIC.ABSTRACTREDUCTION CYCLE PROCESS OF (UO2 + 18 FISSION PRODUCTS) FOR DUPIC FUEL. Firstreduction process of nuclear fuel (U3O8+18 fission products) has been done in a reduction furnaceflowed with hydrogen gas at varying temperatures from 600 – 900 °C for 3 hours. The reductionproduct was UO2 + 18 fission products, of which bulk, tap and true density, O/U ratio, and effect ofpowder crushing were to be determined. Powder that was not crushed has smaller densities than that under going crushing, so that the determination of densities was conducted through crushingstage. It is indicated that the temperature affects the obtained densities, the higher thetemperature the higher the densities of the powder with O/U ratio approaching to 2. Afterobtaining powder of (UO2 + 18 fission) from the first reduction process, the powder was oxidizedat a temperature of 500 oC for 2 hours until the powder (U3O8 + 18 fission) were obtained againand to be used for the second reduction process. The second reduction process was carried outin a way similar to the first reduction process and was repeated up to four cycles.The product ofthe four-cycle reduction process was in the form of (UO2 + 18 fission products) powder, of whichcharacterization was done for its densities and O/U ratio. The reduction process repetitionappears to have enhanced the powder densities and resulted in better O/U ratio. The experimentshows that the relatively good process condition is the third reduction, where the reductiontemperature is 800 oC with heating time for 3 hours. In that condition, the bulkr, tap and truedensity obtained are 2,4594; 3,2096 and 10,2866 g/cm3 (93,77% TD) respectively and the O/Uratio is 2,0192.Key words: Reduction cycle, UO2,U3O8, fission products, DUPIC fuel.