Flowsheet Feasibility Studies Using ABEC Resins for Removal of Pertechnetate from Nuclear Wastes

Abstract

A flowsheet for the extraction and immobilization of 99TcO4 - from radioactive wastes has been developed. The three-stage flowsheet comprises selective sorption of 99TcO4 - by ABEC resins, secondary concentration of 99TcO4 - from H2O by a nonselective silica-based anion-exchange resin, and encapsulation and immobilization of the radionuclide-loaded anion-exchange resin in hydrous titanium oxide microspheres. Each process has been independently tested, and the results are discussed. The utility of this flowsheet in the extraction and immobilization of 99TcO4 - from alkaline radioactive wastes, neutralized nuclear fuel reprocessing streams, alkaline vitrification off-gas scrubber solutions, and solvent wash stages from the treatment of acidic high-level wastes is also presented.

Exceptional Perrhenate/Pertechnetate Uptake and Subsequent Immobilization by a Low-Dimensional Cationic Coordination Polymer: Overcoming the Hofmeister Bias Selectivity

“…Although this has been thought to be not applicable in light that almost all 50 known pertechnetate salts are sparingly soluble, a recent study shows that pertechnetate can be incorporated into the lattice of sodalite as a potential waste form. − However, because of the smaller ionic size of nitrate, the nitrate anion possesses a clear preference to enter the sodalite cage. In addition, although a variety of anion-exchange materials have already been investigated for removing TcO 4 – from either the nuclear waste stream or contaminated aqueous solutions including the state of art anion-exchange polymeric organic resins, − molecular and supramolecular receptors, layered double hydroxides (LDHs), , metal–organic frameworks (MOFs), , and porous organic materials, they cannot be used for further immobilization of TcO 4 – , given these anion-exchange reactions are typically reversible.…”

Zirconium-Based Metal–Organic Framework for Removal of Perrhenate from Water

“…Ion exchange is a widely used industrial process and an essential component of our day-to-day life. , Ion exchange has found application in water purification, semiconductor, pharmaceutical, and a number of other industries. Ion-exchange processes have also found applications in nuclear industries, particularly for radioactive disposal application . For example, several different types of commercial ion-exchange resins have been tested for removal of 99 TcO 4 – from the nuclear waste stream.…”

“…In particular, the chance of groundwater contamination from TcO 4 – is significant because of its high water solubility and ability to propagate through the Earth’s upper crust. ,− Several types of materials have been explored for the effective removal of 99 TcO 4 – from wastewater, including ion-exchange resins, molecular and supramolecular anionic receptors (e.g., cryptands and calixarenes), and inorganic materials (e.g., layered double hydroxides). However, there remains significant room for improvement in terms of uptake, kinetics, and selectivity. ,,− …”

“…Ion-exchange processes have also found applications in nuclear industries, particularly for radioactive disposal application. 3 For example, several different types of commercial ion-exchange resins have been tested for removal of 99 TcO 4 − from the nuclear waste stream. 99 Tc forms as a major byproduct during plutonium production and is present as 99 TcO 4…”

Study on Preferential Selectivity of Nuclear Grade Resin Indion-223 towards some Bivalent Ions

“…The resins remove both radiological and non-radiological impurities [1]. In nuclear power plants these resins are widely applied in-primary coolant (water) purification, treatment of primary effluents and fuel storage pond water, steam generator blow-down demineralization, for treatments of liquid waste and drainage water, purification of boric acid for recycling, condensate polishing (for nuclear power plants with boiling water reactors) [2][3][4][5][6]. Inorganic ion exchangers often have the advantage of a much greater selectivity than organic resins for certain radiologically important species, such as caesium and strontium.…”