A method for the replacement of 137Cs with 40K as a non-hazardous radioactive tracer for open-source decommissioning research applications

Abstract

The potential of 40K as a radioactive tracer analogue of 137Cs in ion exchange experiments is reported. Solutions of varying concentrations of potassium chloride (KCl) have been monitored radiometrically in a sodium iodide well-counter to determine the activity-concentration relationship. Ion exchange reactions using an exemplar ion exchange resin, KCl and non-radioactive caesium chloride (CsCl) solutions have been studied radiometrically. The adsorbed amounts of potassium and caesium are observed, inferred from displaced K+ ions, to be consistent with the total exchange capacity of the resin. Adsorption isotherm models have been applied to the experimental data, with the Freundlich isotherm observed to fit the data with the highest degree of consistency. The reported results indicate that decontamination techniques involving hazardous isotopes of anthropogenic origin such as 137Cs can be developed, evaluated and optimised by substituting a chemically and physically similar non-hazardous radioactive isotope, in this case 40K. This represents a means by which innovative decontamination techniques and regimes might be identified without the need to use 137Cs and thus avoids additional generation of radioactive wastes.