Development of Simulated Process for Medical Fission ⁹⁹Mo Production Using Electroplating UO₂ Target with Low Enriched Uranium

⁹⁹Mo is a kind of important medical radioisotope in nuclear medicine. Conversion from high enriched uranium (HEU) to low enriched uranium (LEU) is a trend for fission ⁹⁹Mo production. In this study, the whole production procedure of fission ⁹⁹Mo had been developed with an emphasis on LEU target by electroplating UO₂ layer on inner wall of a hollow stainless cylinder, dissolution procedure of UO₂ target with heated 6 mol/L HNO₃ solution and radiochemical extraction process of fission ⁹⁹Mo from simulated solution by α-benzoin oxime precipitation, followed by AG1×8 anion exchange and activated charcoal chromatography for further purification. For UO₂ target preparation, optimum parameters for electrodeposition were as follows: 5 mg/mL of uranium concentration, pH=7, 0.5-2 mA/cm² of current density and the temperature of 75-90 ℃. After about 210 hours of electroplating, the resulting film thickness was 42 mg/cm² UO₂ on the inner surface of the tube. In the final ⁹⁹Mo solution, the ratios of the radioactivity of impurities such as ¹³¹I, ⁹⁰Sr, ⁹⁵Zr, ¹⁰³Ru, ²³⁸U to that of ⁹⁹Mo are 4.47×10^-6%, 7.40×10^-7%, 8.67×10^-7%, 2.57×10^-6%, and 1.69×10^-14% respectively that are less than those specified in European Pharmacopoeia, indicating that ⁹⁹Mo purified by the established processing procedure in this work can meet the requirements for medical usage. This work will be expected to pave the way for fission ⁹⁹Mo production at a large scale with LEU target.