Process for Separation of Y-90 from Sr-90 in HNO3 Using Combined Solvent Impregnated Resins of D2EHPA/ Dodecane and CMPO/TBP

Abstract

Yttrium-90 (Y-90) is a radioisotope having a short half-life of 64 hours and emitting high energy beta radiation at 2.28 MeV. It becomes one of the radionuclides being used for the targeted cancer treatment. Y-90 can be generated from radioactive decay of strontium-90 (Sr-90), which is one of the fission products of uranium fuel in the nuclear reactor. Y-90 must be highly pure and free from Sr-90 and other metal ions to achieve high efficient uses. Process for separation and purification of Y-90 from Sr-90 by extraction chromatographic technique has been investigated using two columns packed with different types of solvent impregnated resins namely, 0.3 M di(2-ethylhexyl) phosphoric acid (D2EHPA) in dodecane and 1.0 M n-octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) in tri-n-butyl phosphate (TBP). Feed solutions used in the study were the mixture of the stable isotopes Y and Sr in HNO3 at the concentration ratio Y:Sr of 0.18:756 simulating the equilibrium composition ratio of their radionuclides, Y-90 and Sr-90. Yttrium product yield and recovery of Sr were compared with the separation using a set of commercially available Sr resins and RE resin. High purity of Y product could be obtained from combined columns of D2EHPA and CMPO resins and yield of Y higher than 75% could be achieved. Performance of the in-house prepared resins was evaluated by separation the sample of 90Sr-90Y radionuclides in equilibrium. The extracted Y-90 was quantified for Sr-90 contamination by recounting after 30 days decayed with about 1x10-5 Bq 90Sr per Bq of 90Y. The extraction chromatographic process was found to be easy to operate continuously and there is no need for the treatment of the intermediate solution in the process.