PERHITUNGAN BURN UP PEB U3Si2/Al DENSITAS 4,8 gU/cm3 PASCA IRADIASI POTONGAN BAGIAN MIDDLE

Abstract

BURN UP CALCULATION OF THE MIDDLE PART OF IRRADIATED U3Si2/Al FUEL PLATE WITH 4.8 gU/cm³ DENSITY. Post-irradiation examination with non-destructive and destructive methods is required to study the performance of U3Si2/Al fuel during irradiation at the G. A. Siwabessy Multipurpose Reactor (RSG-GAS). The purpose of the burn-up calculation is to discover the ²³⁵U content that burned in a fuel plate of U₃Si₂/Al during use in RSG-GAS and to prove the burn-up obtained using destructive method by calculation using Origen Code. Therefore, this research performed a burn-up calculation of U₃Si₂/Al fuel plate (with a density of 4.8 gU/cm³) using destructive method through physicochemical analysis. The physicochemical analysis was aimed to determine the isotope content of ²³⁵U, ¹³⁴Cs, and ¹³⁷Cs in the irradiated U₃Si₂/Al fuel plate. The fuel plate was cut at the middle using a diamond cutting machine in a hot cell to obtain a sample cut with a weight of M-1 = 0.056 g, and a duplicate cut was also prepared with a weight of M-2 = 0.075 g. The sample was then dissolved using HCl 6 N and HNO₃ 6N. The results of dissolution was UO₂(NO₃)₂ solution containing isotopic fission such as cesium and uranium. The solution of UO₂(NO₃)₂ was pipetted at 1 mL and then transferred from the hot cell to R.135 (outside the hot cell) to separate ¹³⁴Cs and ¹³⁷Cs from ²³⁵U by a cation exchange method using zeolite from Lampung. The solution of UO₂(NO₃)₂ was pipetted at 100 µL into a vial in duplicates and then 1000 mg zeolite was added. The cation exchange process was then carried out by stirring for 1 h. The separation process resulted in ¹³⁴Cs and ¹³⁷Cs isotopes in the solid phase, while uranium isotopes (²³⁸U, ²³⁵U, ²³⁴U), plutonium (²³⁹Pu, ²³⁸Pu) and other isotopes were in the liquid phase. Separation of uranium from other isotopes was done by anion exchange column method using 1200 mg of Dowex resin. The isotope content of ²³⁵U, ¹³⁴Cs, ¹³⁷Cs, ²³⁹Pu, and 238Pu was then measured using α/- spectrometer, the values of which were subsequently used for burn-up calculation. The result of the burn up calculation is 41.6565 ± 1.687%. The value of burn-up is not significantly different from the burn-up obtained from the calculation using Origen Code, which is 40%.