Irradiation and analysis of Uranyl Nitrate solutions in different Uranium concentrations for use in subcritical reactors for 99Mo production

Different Uranyl Nitrate Solution concentrations and undiluted Uranyl Nitrate Hexahydrate were irradiated in the Kartini TRIGA Mk II reactor to qualitatively assess the radioisotope production feasibility in different neutron fluxes within reactor irradiation facilities. Multiple radioisotope gamma spectrums' were obtained using the Neutron Activation Analysis method without chemical separation prior to detection. The presented methodology serves as a preliminary experiment toward the Subcritical Assembly for 99Mo Production (SAMOP) application in the Kartini reactor. The results show that the concentration and crystallization of Uranyl Nitrate can change the detectability of some radioisotopes in gamma spectrometry. Through a combination of depletion calculation and standardized measurement, some dominant isotopes' gamma peaks from irradiated Uranyl Nitrate are identifiable, and their activity is quantifiable. Although chemical separation is inseparable from fission product analysis using gamma spectrometry, the presented direct measurement establishes a practical and rapid assessment method for the next isotope production development in the Kartini reactor.