Recovery of high specific activity molybdenum-99 from accelerator-induced fission on low-enriched uranium for technetium-99m generators

Abstract

A new process was developed to recover high specific activity (no carrier added) 99Mo from electron-accelerator irradiated U3O8 or uranyl sulfate targets. The process leverages a novel solvent extraction scheme to recover Mo using di(2-ethylhexyl) phosphoric acid following uranium and transuranics removal with tri-n-butyl phosphate. An anion-exchange concentration column step provides a final purification, generating pure 99Mo intended for making 99Mo/99mTc generators. The process was demonstrated with irradiated uranium targets resulting in more than 95% 99Mo recovery and without presence of fission products or actinides in the product.

Nuclear Sample Provenance and Age Determination Using Ruthenium Isotopes

“…Instead, 106 Ru was likely produced in a dedicated target irradiation. Medical isotopes, including 99 Mo, can be produced from the irradiation of a highly enriched uranium (HEU) or low-enriched uranium (LEU) target. , In this process, the target may achieve burnups that are significantly higher than the nuclear fuel itself (as much as 30%). To investigate this possible production pathway, the irradiations of HEU and LEU targets in an LWR were modeled (Figure ).…”

Purification and Concentration of ⁹⁹Mo from a UREX raffinate

“…At this point, the anion column can be treated with NaOH, HCl + oxalic acid, HCl, and NaOH + NaCl to purify and recover 99 Mo. 2…”

“…Traces of Ce have also been observed in the AHA strip stream. 2 The relationship between [HDEHP] and Mo extraction from nitric acid obeys a 2 nd -order dependence, and the full stoichiometry is currently under investigation. 5 Likewise, we have yet to explore whether the AHA strip step can also be leveraged to improve the overall CF (using the inverse of a larger O/A), but the Ds appear to be equally promising and range between 0.1 and 0.5.…”

“…Superconducting electron linear accelerators with high-Z converter targets can generate bremsstrahlung photons and neutron fluxes that can induce photonuclear reactions and LEU fission. 2 After sufficient production intervals, targets can be rotated out and processed while another batch is irradiated. The process flow chemistry is shown in Figure 1.…”

Flowsheet Design for the Purification of Mo-99 and Uranium Target Recovery by Solvent Extraction

“…The United States Department of Energy (DOE) National Security Agency's (NNSA) Office of Material Management and Minimization (M3) is supporting a number of domestic entities to pursue production of the medical isotope generator pair 99 Mo/ 99m Tc without the use of high enriched uranium (HEU). Accelerator-based production-which leverages electron bombardment into a high-Z converter to generate bremsstrahlung photons-can induce photonuclear reactions to produce 99 Mo from uranium targets (Brown et al, 2021).…”