A novel approach for preferential recovery of Sr from (Sr, Th)O₂

Abstract

Quantitative leaching of Sr from homogeneous and calcined (Th,Sr) O₂ in dilute perchloric acid medium suggests the possibility of reducing the hazardousness of discharged nuclear fuel by separation of ⁹⁰Sr, a prominent fission product at dissolution stage itself rather than the conventional approach of its recovery from high level nuclear waste. Apart from mitigating the radiotoxicity of the nuclear waste, recovered ⁹⁰Sr can be employed as a compact heat source and as parent radionuclide for ⁹⁰Y (used in therapy radiopharmaceuticals), provided it can be made available at desired high purity. Leaching behavior of few other fission products was also investigated to quantify their contamination in leached Sr. Feasibility of employing extraction chromatography using Sr selective resin was explored in perchloric acid medium. In this context, the distribution coefficients of ⁸⁵Sr(II), Th (IV), Zr(IV), Y(III), Pd(II) as well as ¹⁵²Eu(III) and ¹³⁷Cs (I) were determined under varying nitric acid/perchloric acid concentration and under varying loading conditions of metal ions. Perchloric acid medium appears better than nitric acid medium for preferential leaching of Sr from (Th,Sr)O₂ as well as for uptake of Sr by Sr selective chromatographic resin.