PEMBUATAN DAN KARAKTERISASI PADUAN UMo SEBAGAI KANDIDAT BAHAN BAKAR NUKLIR TIPE DISPERSI

ABSTRAK PEMBUATAN DAN KARAKTERISASI PADUAN UMo SEBAGAI KANDIDAT BAHAN BAKAR NUKLIR TIPE DISPERSI. Dalam rangka pengembangan bahan bakar dispersi UMo-Al berpengayaan rendah (< 20% 235U) telah dilakukan pembuatan paduan UMo kadar 7, 8, 9, 10 dan 11% Mo. Paduan UMo dibuat dengan teknik peleburan di dalam tungku busur listrik bermedia gas argon dengan tekanan 0,6 bar. Peleburan setiap paduan dilakukan 5 kali dan ingot yang diperoleh dibuat serbuk dengan cara mekanik (penumbukan). Hasil uji menunjukkan bahwa ingot sangat ulet, mikrostruktur pada bagian dekat pendingin memanjang dan bagian tengah membesar, sedangkan kekerasan cenderung naik dengan meningkatnya kadar Mo. Keuletan ingot menyebabkan pembuatan serbuk dengan cara penumbukan sulit dan serbuk yang dihasilkan berbentuk pipih. Data uji difraksi sinar-X menunjukkan bahwa pada komposisi 7% Mo didominasi fase αU dan pada 11% didominasi oleh fase δ2-U2Mo. Fase α-U yang mempunyai struktur kristal ortorombik terdapat pada sudut 2θ masing-masing sebesar 26,9o; 33,9º; 38,8o; 52,9o dan 78,4o serta pada bidang 011, 020, 110, 121 dan 211 sedangkan fase δ2-U2Mo muncul pada sudut 2θ sebesar 28,02o; 37,02o; 38,10o; 53,60o dan 67,36o serta pada bidang 101, 110, 203, 200 dan 213. Kualitas ingot UMo hasil peleburan cukup baik, meski mengalami kesulitan dalam membuat serbuk dengan penumbukan. Oleh karena itu perlu dipilih metode proses pembuatan serbuk yang sesuai. KATA KUNCI: Paduan UMo, Bahan bakar tipe dispersi, Difraksi sinar-X, Kristal ortorombik ABSTRACT PRODUCTION AND CHARACTERIZATION OF UMo ALLOY AS CANDIDATE OF NUCLEAR FUEL DISPERSION TYPE. In order to develop low enrichment (< 20% 235U) UMo-Al dispersion fuel, experiment has been conducted to prepare UMo alloy with 7, 8, 9, 10 and 11% Mo respective ly. Each UMo alloy was prepared by arc melt technique in argon gas medium. The melting of every alloy was performed 5 times, and then the alloys were powdered by mechanical method (grinding and milling). Examination of the results showed that the alloys were very ductile, microstructures of the areas near the cooling were stretched lengthwise while the middle parts enlarged, and the hardness had a tendency to increase with increasing Mo content. The ductility of the ingots caused difficulty in powder production by grinding and milling, and the produced powder was flat in form. Examination of X-ray diffraction data indicated that at 7% composition the alloy was dominated by αU phase and at 11% Mo composition by δ2-U2Mo. The αU phase with orthorombic crystal structure was observed at angle 2θ of 26.9o, 33.9º, 38.8o, 52.9o and 78.4o as well as in the planes of 011, 020, 110, 121 and 211 whereas the δ2-U2Mo phase appeared at angle 2θ of 28.02o, 37.02o, 38.10o, 53.60o and 67.36o in the planes of 101, 110, 203, 200 with 213. The quality of UMo alloy obtained by melting was quite satisfactory despite difficulties encountered in preparing the powder by grinding and milling. Therefore, it is necessary to choose a reliable manufacturing process. FREE TERMS: UMo alloy, Dispersion fuel, X-ray diffraction, Orthorhombic crysta