Evaluation of adsorption behaviour of selenium onto zeolite-based composite barrier material for intermediate deep radioactive waste repository

The radionuclide ⁷⁹Se is a potential radio-ecological concern due to its long half-lives and its capacity to be readily incorporated into the natural life cycle from radioactive waste repositories. This study aimed to reveal the role of barrier materials including zeolite in the transfer of selenium from radioactive waste repository areas to the biosphere. The interaction between selenium (IV) and the barrier material was evaluated by examining different parameters. In the event of an accident that may occur, the environmental and health risks that the ⁷⁹Se may pose were evaluated within the scope of possible dose values using a Monte Carlo-based simulation program. As a result, it has been determined that the composite barrier material used plays an important role in preventing the transfer of selenium from the waste storage area to the biosphere. Total carcinogenic risk (TCR) values for ingestion way were found from 4.93E-17 to 4.03E-16 for adults, and from 6.30E-22 to 5.16E-21 for infants. TCR values for dermal way are from 5.28E-21 to 4.32E-20 for adults and range from 7.74E-31 to 6.34E-30 for infants.