Decontamination of Waste Solution from Davies-Gray Analyses in a Pilot-Facility for Process Development

Abstract

A pilot plant for removal of radioactivity from solutions has been built and tested. In an initial trial, uranium remaining in a Davies-Gray-analysis waste-solution was reduced 300,000-fold to 0.2 ppb by passing the solution through Diphonix^TH ion-exchange columns. The columns were regenerated (and the uranium was recovered) with HEDPA (1-hydroxyethane-1,1-diphosphonic acid). The latter was destroyed with H²O², and the uranium was reduced and precipitated as a phosphate. Final purification of the dissolved precipitate employed a U/TEVA·Spec^TH (dipentyl pentylphosphonate) extraction chromatographic column. Studies of matrix effects upon the uptake of uranium by the Diphonix^TH led to an initial dilution of the waste solution and to a reduction of ferric ion.