Technetium (Tc)/Rhenium (Re) Solubility and Leaching Behavior from Waste Forms: An Overview (2022)

Bhupendra Kumar Singh, Jueun Kim, Donghun Pak, Kyungwon Kim and Wooyong Um

Frontiers Nuclear Engineering (Front. Nucl. Eng.), FNUEN-01-1112080

DOI : 10.3389/fnuen.2022.1112080

ABSTRACT

Technetium-99 (⁹⁹Tc), a radionuclide generated from nuclear industry is a great environmental concern because of its long half-life (2.13 × 10⁵ years) and high mobility in environment. Therefore, apposite management of ⁹⁹Tc is imperative to control its hazardous radiological impact on humans and other livings. So far, the major strategy implementation has been the solidification and immobilization of ⁹⁹Tc radioactive waste in various matrices as waste forms and disposal in deep geological repository. However, by passing the time, ⁹⁹Tc may leach out/solubilize from the waste forms under different geochemical/environmental conditions. In this minireview, we discuss some key contributions towards the solubility of ⁹⁹Tc and rhenium (Re; a well-known surrogate of ⁹⁹Tc) from different waste forms. Specifically, we review the solubility of ⁹⁹Tc from glass, cement, ceramic, and geopolymer waste forms. The final section (conclusion) presents a short summary and future challenges need be addressed to impede the solubility of ⁹⁹Tc from the designed waste forms. We believe this minireview will be beneficial to provide a significant insight on the solubility of ⁹⁹Tc from aforementioned waste forms and in the design of robust matrices to minimize/prevent ⁹⁹Tc migration in various environments.