Impact of water flooding on hard cement-recycled polystyrene composite immobilizing radioactive sulfate waste simulate

摘要

Radioactive sulfate wastes are generated from boiling water reactors (BWRs) and should be immobilized before their disposing to avoid the back release of their hazardous components under the impact of water flooding incident in the disposal site, which gives rise of secondary contamination at the surrounding area. A cement-polymer composite formulated from recycled post-consumer polystyrene foam waste and Portland cement was proposed as an incorporating matrix for solidification/stabilization (S/S) of sulfate waste simulate in laboratory scale experiments. To imitate a water-flooding incident, the reached solidified waste form was completely immersed in three types of water, namely, tap-, ground-, and seawater for increasing periods up to 420 days. Compressive strength, porosity and mass change of the solidified waste samples were evaluated at the end of various immersion periods. Besides, FT-IR, XRD, SEM with EDX analyses were performed to follow the internal changes of the product post the immersion. Based on the data obtained, it could be concluded that the comparative stability of the nominated composite under the impact of water flooding incident candidates it as an acceptable matrix for immobilizing the radioactive sulfate wastes. In addition to its stability, the formulated composite have the advantage of upgrading post-consumer non-biodegradable polystyrene foam waste, therefore, thus introducing a sustainable technique and saving landfill area by using significant amounts of one of the major municipal solid wastes. (C) 2019 Elsevier Ltd. All rights reserved.