A Methodology for Simulating Radionuclide Diffusion in Unsaturated Soils

Abstract

In this paper, a methodology that can be employed to simulate radionuclide migration through unsaturated soils, under laboratory conditions, has been developed and reported. This was achieved with

Diffusion experiments for estimating radiocesium and radiostrontium sorption in unsaturated soils from Spain: Comparison with batch sorption data

“…The highest D a (Cs) value was observed in the FROCOR soil (5.9 × 10 −11 m 2 s −1 ), and the lowest values were measured in MALAGA and CABRIL soils (1.0 × 10 −13 m 2 s −1 ). The D a (Sr) and D a (Cs) values obtained in the present work were similar to those obtained by Rakesh et al [18] in two unsaturated soils. However, they are around one and two orders of magnitude higher than D a values reported in literature for compacted bentonites [9] at higher bulk densities than the ones achieved in this study for soils.…”

“…90 Sr, 137 Cs, 241 Am, 226 Ra, 229 Th or 237 Np) and non-reactive radionuclides, such as 36 Cl or 124 I, inside the spent radioactive fuel [3] or in the materials that can be used as engineered barriers [4][5][6][7][8][9][10]. Nevertheless, only a few studies have examined radionuclide diffusion in soils [11][12][13], and even fewer have looked at soil under unsaturated conditions [14][15][16][17][18]. Therefore, laboratory studies of radionuclide transport in unsaturated soils are required to examine the behavior of the radionuclides in hydrogeological conditions that reconstruct the in situ conditions.…”

Novel Techniques to Simulate and Monitor Contaminant–Geomaterial Interactions

“…This process might result in generation of leachates, semisolids and Fig. 11 Details of the reactor employed for hydrothermal activation of the fly ash gases, which tend to migrate through the appropriate pathways in the far-and near fields to contaminate the geoenvironment [137,138]. The decomposed geomaterial should be treated as a 'multi-phase system,' and its conceptualization and modeling is the prime focus of The ENVGEOs, presently, as discussed in the following.…”

Lysimetric studies for modelling radioactive contaminant transport in soils

“…• no fl ow condition along its sides The spiked soil (i.e., the soil contaminated with a certain concentration of a contaminant) and the in situ soil, contained in the lysimeter are defi ned by inputting their properties such as concentration of the contaminant, textural classifi cation, porosity (η), bulk density (γ t ), saturated soil hydraulic conductivity (k sat ), decay constant (R), Residual Moisture Content (RMC) and distribution coeffi cient (k d ) (Rao et al, 2009;Rakesh et al, 2009), longitudinal and transverse dispersivity coeffi cients (α L and α T ) and effective diffusion coeffi cient (D e ), as listed in Table 6 (Rakesh, 2005). …”

“…Near/subsurface disposal technique is commonly adopted for disposal of low level radioactive wastes (Piet et al, 2003;Mayers et al, 2005;Bucur et al, 2006;Rakesh et al, 2009). In the due course of time, or in case of any eventuality, the radioactive contaminants (isotopes) get released in the surrounding soil mass which results in a threat to the geoenvironment (i.e., soils, rocks and ground water) (Francis, 1994;Mollah and Ullah, 1998;Yim and Simonson, 2000;Plummer et al, 2004).…”