Experiments for separation and purification of Mo-99 from uranium solution with fission products as tracers

Technetium-99 m (99mTc, T1/2 = 6 hours), one of the most utilised radioisotopes in nuclear medicine, is generated through the beta decay of 99Mo (T1/2 = 66 hours) and which will decay through isomer transition to 99Tc ( T1/2 = 2.105 years) through the emission of a gamma radiation with the energy of 0.140 MeV. The work presents the phases of the process of Mo separation and purification at a tracer level. The tests performed in the laboratory have established the optimum conditions for the separation and purification of Molybdenum. To establish the separation and purification parameters, a synthetic solution which contains the elements which result following the irradiation of a low enriched Uranium foil weighing 10 g (∼20 % 235U). To mark this solution, about 13 mg of UO2 10% 235U was irradiated for 2000 s, at a flux of about 7x1012 n/cm2s. This amount of UO2 will be added to the above-mentioned solution after dissolution. The method for separating the Molybdenum from irradiated Uranium solution is one of selective precipitation of Mo with α-benzoin-oxyme (α- BO). To purify the Molybdenum solution, two purification columns were utilised. Their role was to absorb the impurities remained in the mass of the precipitate. They and the Molybdenum have passed into the solution simultaneously, allowing the Molybdenum to pass. These columns are: the column with active charcoal (AC)+ active charcoal covered with silver (AgAC); active charcoal column (AC)+active charcoal covered with silver (AgAC)+hydrated zirconium oxide (HZO). Although all the phases of the process are performed with high yields, the final yields of recovery of Mo from U solutions are higher than 80%. (authors)