Separation of Carrier-Free ⁹⁰Y from High Level Waste by Extraction Chromatographic Technique Using 2-Ethylhexyl-2-ethylhexyl Phosphonic Acid (KSM-17)

Abstract

An extraction chromatographic technique has been developed for the separation of carrier-free ⁹⁰Y from the ⁹⁰Sr present in the high level waste (HLW) of the Purex process. When a Purex HLW solution in 2–3 M HNO₃ is passed through a CMPO-Chromosorb-102 (CAC) column, all the trivalent, tetravalent, and hexavalent ions are sorbed. The effluent from this experiment, after adjusting the pH to 2 with NaOH, was passed through a 2-ethylhexyl-2-ethylhexyl phosphonic acid (KSM-17)-Chromosorb-102 (KSMC) extraction chromatographic column where only ⁹⁰Y was sorbed. All the other ions (⁹⁰Sr, ¹³⁷Cs, ¹²⁵Sb, ¹⁰⁶Ru, ¹⁰⁶Rh, etc.) were washed off with dilute HNO₃ (pH 2), and carrier-free ⁹⁰Y was eluted with 0.5 M HNO₃. This technique can yield ⁹⁰Y in mCi levels in pure form for medical applications. The ⁹⁰Sr can be used repeatedly after allowing for ⁹⁰Y buildup.

Acknowledgments