Characterization of radioactive waste generated during molybdenum-99 batch production

Abstract The routine production of molybdenum-99 ( 99 Mo) at the Isotope Production Facility, Bhabha Atomic Research Centre, using neutron activation of molybdenum trioxide generates both liquid and solid radioactive waste. This study aims to characterize the radionuclide inventory of waste streams generated during weekly batch production using high-purity germanium gamma spectrometry. Liquid primarily contained short-lived 99 Mo (~98.5%), with minor presence of 92m Nb, 59 Fe, and 60 Co. Solid waste, while also dominated by 99 Mo (~97.2%), exhibited a more diverse isotopic profile including fission products and activation products such as 137 Cs (0.03%), 106 Ru (0.12%), 95 Zr (0.07%), and 60 Co (1.14%). Additionally, 51 Cr (0.97%) was present alongside trace levels (~0.1%) of 134 Cs, 65 Zn, 103 Ru, 154 Eu, and 95 Nb. The estimated annual activity of radioactive waste was ~ 30 μCi for liquid and ~ 9 mCi for solid waste. Most short-lived radioactivity decays during interim storage, while residual long-lived isotopes remain well below exemption levels as per International Atomic Energy Agency General Safety Guide-17. These findings support the implementation of safe and compliant waste management practices.