Electro-Decontamination of Spent Ion Exchange Resins Contaminated with Iron Oxide Deposits under Dynamic Conditions

Eduard Tokar,Andrei Egorin,Anna Matskevich

doi:10.3390/su13094756

Eduard Tokar, Andrei Egorin + Show 1 more

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https://doi.org/10.3390/su13094756

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Abstract

A method for the electro-decontamination of spent ion exchange resin contaminated with hematite under dynamic conditions using sulfuric acid solutions has been suggested. It has been shown that decontamination under dynamic conditions excludes the secondary adsorption of radionuclides on ion-exchanger sites. The efficiency of this approach has been compared to that of control experiments without direct current treatment. A positive effect of the introduction of Fe2+ on the rate of dissolution of hematite has been demonstrated. This allows for decreasing the concentration of the sulfuric acid solution without decreasing the decontamination efficiency.

Highlights

The steel elements of a nuclear power plant (NPP) continue to become partially corroded in the course of its service
Prior to the start of the experiment, the cation-exchanger was washed with a 1 M solution of HNO3 under dynamic conditions; thereafter, it was washed free from the acid residues with distilled water and stored in a flask with a plug stopper
The possibility of the adsorption of Fe(II) from acidic media by hematite was confirmed by the results provided by B-H Jeon et al [26]

Summary

Introduction

The steel elements of a nuclear power plant (NPP) continue to become partially corroded in the course of its service. As a result of this process and subsequent hydrolysis, iron oxide/hydroxide particles are formed in the condensation water [1,2]. Such particles, generally called “crud”, have a mixed chemical composition, which is mainly represented by iron and, to a lesser extent, chromium, nickel, cobalt, and zinc [3,4]. The crud is removed from the NPP system water by means of mechanical filtration on columns with ion-exchange resins, followed by reverse washing. In the process of mechanical filtration, some parts of the crud bind irreversibly due to diffusion in the pore space of an ion-exchange resin grain [5], which complicates the regeneration and subsequent disposal of spent ion-exchange resins (SIER)

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