Stabilisation/solidification of137Cs-contaminated soils using novel high-density grouts: γ-ray shielding properties, contaminant immobilisation and a γRS index-based approach for in situ applicability.
In this work, γ-ray shielding and Cs immobilisation performances of high-density magnetite (MG) and iron powder (IP) in Portland cement (PC) based-S/S treatment were investigated. Experimental results were elaborated using a γ-radiation shielding (γRS) index-based approach for assessing the effectiveness of in situ S/S of137Cs-contaminated soils. 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 γ-ray shielding performance, whereas a further material addition decreases the S/S shielding performance. The highest γRS index of ∼26% (662 keV) was found in the case of IP addition (33.3%). The use of MG-mixes allows reaching slightly slower γRS index jointly with the highest Cs-immobilisation of 97.8%. In this case, calculation shows a maximum137Cs-contamination level successfully treatable by in situ S/S up to ∼2.9 or ∼14.5 kBq kg-1for the realistic or low probability scenario, respectively, highlighting the possibility to remediate a very wide range of real contamination. Findings show MG - PC S/S as the best choice and could provide a basis for decision-making of S/S remediation of137Cs-contaminated sites.
Department of Civil Engineering and Architecture, University of Catania, Viale A. Doria, 6, 95125 Catania, Italy; Laboratori Nazionali del Sud - INFN, Via S. Sofia, 62, 95125 Catania, Italy. Electronic address: ppfalci@dica.unict.it.
Pietro P
PP
Falciglia
Laboratori Nazionali del Sud - INFN, Via S. Sofia, 62, 95125 Catania, Italy; Department of Physics and Astronomy, University of Catania, Viale A. Doria, 6, 95125 Catania, Italy.
Stefano
S
Romano
Department of Civil Engineering and Architecture, University of Catania, Viale A. Doria, 6, 95125 Catania, Italy.
Federico G A
FGA
Vagliasindi
D002588:Cesium Radioisotopes / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D052203:Ferrosoferric Oxide / Q000737:chemistry; D005720:Gamma Rays; D007501:Iron / Q000737:chemistry; D012990:Soil Pollutants, Radioactive / Q000737:chemistry*
D002588:Cesium Radioisotopes; D012990:Soil Pollutants, Radioactive; D007501:Iron; D052203:Ferrosoferric Oxide
137-cesium ((137)Cs); Effective dose; Environmental risk; High-density γ-ray shielding materials (iron powder, magnetite); Stabilisation/solidification; γRS index