Recovery of radio chemically pure 90Sr suitable for milking clinical grade 90Y from high level liquid waste: A process developmental investigation

Abstract

Radio chemically pure ⁹⁰Y is desired for its use as radio therapeutic agent. As a modern practice ⁹⁰Y, is milked from its parent ⁹⁰Sr, thus the radiochemical purity of resulted ⁹⁰Y will be governed by the purity of its parent Sr. High level liquid waste (HLLW) generated from the spent nuclear fuel reprocessing contains ample quantity of ⁹⁰Sr, the parent of its β decaying product ⁹⁰Y. In our previous studies it was explored that BOC8A/ Nitrooctane can be preferably used to recover ⁹⁰Sr in 0.01 M HNO₃ from HLLW with ∼1 % Am (III) & Eu (III) contamination. Thus, ⁹⁰Sr recovered needs multi step purification before milking ⁹⁰Y. To minimise the number of step in purification to obtain ultrapure ⁹⁰Sr (10⁻⁹ Ci alpha / Ci Sr) a well-known hydrophilic supramolecule 18C6 is introduced in the stripping step. A new process scheme has been developed using BOC8A, 18C6 and Tetra-2-ethylhexyl diglycolamide etc. CHON based extractant to obtain highly pure ⁹⁰Sr product. The mechanism and effect of different parameters on stripping of Sr with 18C6 have also been investigated in detail. The stripping phenomenon has been found to be spontaneous at 298 K and the change in Gibb’s free energy was found to be - 22.9 kJ mol⁻¹K⁻¹