Burnup determination of Full-Scale, High-Density U3Si2-Al (4.8 gU/cc) fuel plate using destructive radiochemical technique

Burnup determination of the U3Si2-Al fuel plate (FP) with a density of 4.8 gU/cc has been carried out using the destructive method with the isotopes Cs-137 and U-235 as indicators. The FPs were irradiated in the G.A. Siwabessy multi-purpose reactor (RSG-GAS). Burnup determination begins by cutting the U3Si2-Al FP in a duplicate manner on three positions, top, middle, and bottom, then dissolving it with HCl and HNO3 to obtain a fuel solution containing fission products of Cs-134, Cs-137, U-235 and other isotopes. The separation of Cs-137 from U-235 was carried out by the cation–anion exchange method using Lampung zeolite with the entire process carried out in a hot cell. The product resulting from the separation was the isotope Cs-137 in the solid phase, while U-235 was in the liquid phase. The amount of Cs-137 and U-235 isotopes were measured with an alpha- and gamma-spectrometry, so the weight of Cs-137 and U-235 can be used to determine the burnup of each FP. The results of burnup calculation of the 4.8 gU/cc U3Si2-Al FP using the destructive method were 25.06%, 57.96%, and 35.20% on the top, middle, and bottom respectively. There is no significant difference between nominal burnup derived from the weight of the isotopes Cs-137 and U-235 obtained with the destructive method, with the most significant difference to the non-destructive method being 10.26% when using the Cs-137.