Improvement of the technological process of deep purification of low-level liquid wastes

Abstract

Radionuclides are removed from low-salt ( < 1 g/liter) low-level ( < 10 -5 Ci/liter, or 370 kBq/liter) radioactive liquid wastes by a technology that includes coagulation and subsequent desalinization on ion-exchange resins in H and OH form [1][2][3]. The operations of deposition and periodic regeneration of the ionites with acid and alkali increase the volume of secondary wastes, which correspondingly increases the cost of solidification and subsequent storage and burial of the wastes [4]. One way to decrease the amount of secondary wastes and lower the cost of the purification process is to use ionites in a salt form [5]. When a cationite is transferred into Na form, the univalent cations, which constitute up to 50% of the total salt content, will not be retained by the ionites.The transfer of an anionite into a salt form will make it possible to eliminate expensive alkali.To determine the possibility of using ionites in a salt form for removing radionuclides from liquid wastes, an apparatus with three sorption columns, filled with the cationites KU-2 ;ind KB-51 in the Na form and AV-17 in the NO 3 form, was developed at the Moscow reprocessing plant. Solutions were fed into the column (load volume 5 liters, feed rate of solution four-column volumes V c per 1 h) after the standard coagulation with iron hydroxide (Tables 1 and 2). Data on purification by the H-OH ionite scheme, are presented for comparison.