Naseem Irfan

Severe nuclear accidents can cause over-pressurization and serious damage to the containment of a nuclear power plant, which can result in the release of radioactivity into the environment. Filtered containment venting systems are a nuclear safety system that is designed to control over-pressurization and prevent radioactive fission products from spreading into the environment in the case of a severe accident. Iodine is one of the most harmful products among this list of fissionable products, as it can cause thyroid cancer. The removal of iodine is very important in order to ensure the safety of people and the environment. Thus, an indigenous lab scale setup of this system was developed at PIEAS to conduct research on iodine removal. It is comprised of a compressor for replicating high-pressure accident scenarios, a heater to keep iodine in a vapor form, a dosing pump for the injection of iodine, and a venturi scrubber, submerged in the scrubbing column, containing a solution of 0.2% sodium thiosulphate and 0.5% sodium hydroxide. Inlet and outlet samples were trapped in 0.1 M KOH solution and analyzed via UV-VIS spectroscopy. Operating parameters play an important role in the working of a venturi scrubber. The throat velocity was varied to determine its influence on the removal efficiency of iodine. An increase in removal efficiency was observed with an increase in throat velocity. A removal efficiency of >99% was achieved, which fulfilled the requirements for FCVS.

Efficient and cost-effective removal of radioactive iodine (radioiodine) from radioactive contaminated water has become a crucial task, following nuclear power plant disasters. Several materials for removing radioiodine have been reported in the literature. However, most of these materials exhibit some limitations, such as high production cost, slow adsorption kinetics, and poor adsorption capacity. Herein, we present silver/iron oxide nanocomposites (Ag/Fe₃O₄) for the efficient and specific removal of iodine anions from contaminated water. The Ag/Fe₃O₄ were synthesized using a modified method and characterized via scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analyses. This adsorbent showed a high adsorption capacity for iodine anions (847 mg/g of the adsorbent) in pure water. Next, Ag/Fe₃O₄ was applied to the removal of radioiodine, and high removal efficiencies were observed in water. In addition, its desalination capacity was retained in the presence of competitive ions and varied pH. After the adsorption process, Ag/Fe₃O₄ was easily removed from the water by applying an external magnetic field. Moreover, the same operation can be repeated several times without a significant decrease in the performance of Ag/Fe₃O₄. Therefore, it is expected that the findings presented in this study will offer a new method for desalinating radioiodine in various aqueous media.