[en] It has been done a recovery and analysis of ¹³⁷Cs isotope and heavy elements which are present in the irradiated U₃Si₂-Al fuel plates. The recovery is carried to obtain composition of ¹³⁷Cs, ²³⁵U and ²³⁹Pu isotopes which will be used for burn up calculation. The recovery has been done by cation exchange method with Lampung zeolites. About 150 µL of irradiated U₃Si₂-Al fuel plates solution has been taken and being placed into 4 vials. Moreover, a number of Lampung zeolites have been added into each vial with a variation of weight about 300, 400, 500 and 600 mg. A process of cation exchange has been carried out with a shaker at 200 rpm for 60 minutes and left it for 24 hours. The result of cation exchange process has indicated that there is separation between ¹³⁷Cs-zeolite and U-Pu which present in the liquid phase. The ¹³⁷Cs-zeolite are then weighed and analysed using a spectrometer-alpha. The analysis of U and Pu in the liquid phase has been done by taking 250 µl of supernatant solution and being processed with electrodeposition by using buffer media of (NH₄)₂SO₄ 1 M with a current of 1.2 Ampere and electrode's distance at 10 mm for 2 hours. After the electrodeposition process, the solution has been analysed using spectrometer alpha to obtain the composition of U and Pu isotopes. The results show that the optimum weight of Lampung Zeolites for the separation from heavy elements in irradiated fuel plates is 500 mg. Furthermore, it has been obtained ¹³⁷Cs about 0.0118 µg, ²³⁵U 0.3110 µg and heavy elements 1.5611 µg with a measurement deviation about 0.00001 µg. (author)