Investigation on Novel High–Density Grouts for In Situ Stabilisation/Solidification of 137Cs–Contaminated Soils

Gamma-ray shielding and Cs immobilisation of high-density magnetite (MG) and iron powder (IP) in Portland cement (PC) based-S/S treatment of Cs – contaminated soils were investigated. Gamma ray spectrometer with High Purity Germanium (HPGe) detector was used for ??-ray emission measurement. Main results reveal that the replacement of PC by MG or IP (up to 50%) leads to a marked increase (up to about 4-fold) in the ??- ray shielding performance. A higher MG amount leads to a decrease that performance. The highest ??RS index of ~26% (662 keV) was found in the case of IP addition (33.3%). The use of MG-mixtures allows reaching slightly slower ??RS index jointly with the highest Cs-immobilisation of 97.8%. Results revealed MG - PC S/S as the best choice and could provide a basis for decision-making of S/S remediation of 137Cs-contaminated sites.