Comparison of Fission and Non-Fission Methods in Mo-99 Radioisotope Production

The utilization of the G.A. Siwabessy Multipurpose Reactor (RSG-GAS) includes the production of radioisotopes. Among the radioisotopes produced by RSG-GAS is Mo-99. The Mo-99 radioisotope is used in the production of Technetium-99m ( 99m Tc), which is used in diagnostic imaging in the medical field. There are two ways to produce the Mo-99 radioisotope. First, with a fission scheme using Low Enriched Uranium (LEU) in the form of UO 2 . Second, with a non-fission scheme by irradiating MoO 3 samples. The aim of this study is to analyze the production results of radioisotopes using the fission scheme compared to the non-fission scheme using the ORIGEN 2.1 program. In this study, an MoO 3 sample weighing 8.753 grams is compared to UO 2 weighing 8.753 grams with the composition: U-235 1.508 grams, U-238 6.206 grams, and O-16 1.039 grams. Then, variations in the irradiation position in the reactor were made, namely at the Central Irradiation Position (CIP) at locations E7 and D6, as well as the Irradiation Position (IP) with reactor power of 5, 15, and 30 MWt. The calculation results show that at CIP-D6 with a power of 30 MWt, the production result of the non-fission scheme is 7.05 Ci. Meanwhile, the production result of the fission scheme under the same conditions is 797.10 Ci. This is due to the better ability of UO 2 to capture neutrons needed in nuclear reactions, as well as having more uranium isotopes that easily undergo neutron fission. Therefore, for Mo-99 production, it is recommended to use the fission scheme.