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Interaction of (3)H(+) (as HTO) and (36)Cl(-) (as Na(36)Cl) with crushed granite and corresponding fracture infill material investigated in column experiments.

Štamberg K, Palágyi Š, Videnská K, Havlová V - J Radioanal Nucl Chem (2013)

Bottom Line: Furthermore, the research was focused to quantification of the effect of grain size on migration of studied radionuclides.The results showed that influence of grain size on sorption of (3)H(+) and (36)Cl(-) was negligible.On the other hand, the influence of grain size on Peclet numbers value and on dispersion coefficient was observed for both crystalline materials, namely in agreement with theoretical suppositions that the values of Peclet numbers decrease with increasing grain size and values of dispersion coefficient increase.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, 115 19 Prague, Czech Republic.

ABSTRACT

The transport of (3)H(+) (as HTO) and (36)Cl(-) (as Na(36)Cl) was investigated in the dynamic system, i.e., in the columns filled with crushed pure granite and fracture infill of various grain sizes. The aim of column experiments was to determine important transport parameter, such as the retardation, respectively distribution coefficients, Peclet numbers and hydrodynamic dispersion coefficients. Furthermore, the research was focused to quantification of the effect of grain size on migration of studied radionuclides. The experimental breakthrough curves were fitted by a model based on the erfc-function, assuming a linear reversible equilibrium sorption/desorption isotherm, and the above mentioned transport parameters were determined. The results showed that influence of grain size on sorption of (3)H(+) and (36)Cl(-) was negligible. Retardation and distribution coefficients of both tracers converged to one and zero, respectively, in case of all fractions of crushed granite and infill material. Generally, the presumed ion exclusion of (36)Cl in anionic form was proved under given conditions, only very weak one seems to exist in a case of infill material. In principal, both radionuclides behaved as non-sorbing, conservative tracers. On the other hand, the influence of grain size on Peclet numbers value and on dispersion coefficient was observed for both crystalline materials, namely in agreement with theoretical suppositions that the values of Peclet numbers decrease with increasing grain size and values of dispersion coefficient increase.

No MeSH data available.


Related in: MedlinePlus

The dependences of Pe, calculated for sorption edges of HTO, on the average grain size (AGS) of crushed pure granite (open diamond ± SD) and infill material (open square ± SD) (R2 is regression coefficient)
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Fig5: The dependences of Pe, calculated for sorption edges of HTO, on the average grain size (AGS) of crushed pure granite (open diamond ± SD) and infill material (open square ± SD) (R2 is regression coefficient)

Mentions: The graphical evaluation of PeS (corresponding to the sorption edge of BTC in column experiments, e.g., see Figs. 1, 3) is depicted in Fig. 5 (for HTO) and 6 (for 36Cl−). We see that the dependences in both figures (except of PeS values for the coarsest fraction in Fig. 6) in principal agree with the theory mentioned above. In addition, the regressions by means of exponential (Fig. 5) and polynomial (Fig. 6) function, having the acceptable values of regression coefficients, reflect the physical meaning of obtained dependences. Of course, the differences between behavior of HTO and 36Cl− exist. Again, these differences are approximately comparable with the results obtained in [10] according to which: experiments with natural fracture column showed higher retardation and dispersion of tritiated water in comparison with chlorine probably due to ion-exclusion of the anions in fracture infill. From this point of view, if we compare the infill material values of PeS ± SD, summarized in Table 4; Fig. 5 (tracer HTO), and in Table 6; Fig. 6 (tracer 36Cl− as Na36Cl), we see that the similar results were obtained, namely, there are lower PeS values (higher dispersion) of HTO in infill material columns, or worse approach to the plug flow, in comparison with values of 36Cl− (except of column No. PDM1-2b, but if the values of PeS ± SD are taken into account, it approximately holds for this column, too).Fig. 5


Interaction of (3)H(+) (as HTO) and (36)Cl(-) (as Na(36)Cl) with crushed granite and corresponding fracture infill material investigated in column experiments.

Štamberg K, Palágyi Š, Videnská K, Havlová V - J Radioanal Nucl Chem (2013)

The dependences of Pe, calculated for sorption edges of HTO, on the average grain size (AGS) of crushed pure granite (open diamond ± SD) and infill material (open square ± SD) (R2 is regression coefficient)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4514635&req=5

Fig5: The dependences of Pe, calculated for sorption edges of HTO, on the average grain size (AGS) of crushed pure granite (open diamond ± SD) and infill material (open square ± SD) (R2 is regression coefficient)
Mentions: The graphical evaluation of PeS (corresponding to the sorption edge of BTC in column experiments, e.g., see Figs. 1, 3) is depicted in Fig. 5 (for HTO) and 6 (for 36Cl−). We see that the dependences in both figures (except of PeS values for the coarsest fraction in Fig. 6) in principal agree with the theory mentioned above. In addition, the regressions by means of exponential (Fig. 5) and polynomial (Fig. 6) function, having the acceptable values of regression coefficients, reflect the physical meaning of obtained dependences. Of course, the differences between behavior of HTO and 36Cl− exist. Again, these differences are approximately comparable with the results obtained in [10] according to which: experiments with natural fracture column showed higher retardation and dispersion of tritiated water in comparison with chlorine probably due to ion-exclusion of the anions in fracture infill. From this point of view, if we compare the infill material values of PeS ± SD, summarized in Table 4; Fig. 5 (tracer HTO), and in Table 6; Fig. 6 (tracer 36Cl− as Na36Cl), we see that the similar results were obtained, namely, there are lower PeS values (higher dispersion) of HTO in infill material columns, or worse approach to the plug flow, in comparison with values of 36Cl− (except of column No. PDM1-2b, but if the values of PeS ± SD are taken into account, it approximately holds for this column, too).Fig. 5

Bottom Line: Furthermore, the research was focused to quantification of the effect of grain size on migration of studied radionuclides.The results showed that influence of grain size on sorption of (3)H(+) and (36)Cl(-) was negligible.On the other hand, the influence of grain size on Peclet numbers value and on dispersion coefficient was observed for both crystalline materials, namely in agreement with theoretical suppositions that the values of Peclet numbers decrease with increasing grain size and values of dispersion coefficient increase.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, 115 19 Prague, Czech Republic.

ABSTRACT

The transport of (3)H(+) (as HTO) and (36)Cl(-) (as Na(36)Cl) was investigated in the dynamic system, i.e., in the columns filled with crushed pure granite and fracture infill of various grain sizes. The aim of column experiments was to determine important transport parameter, such as the retardation, respectively distribution coefficients, Peclet numbers and hydrodynamic dispersion coefficients. Furthermore, the research was focused to quantification of the effect of grain size on migration of studied radionuclides. The experimental breakthrough curves were fitted by a model based on the erfc-function, assuming a linear reversible equilibrium sorption/desorption isotherm, and the above mentioned transport parameters were determined. The results showed that influence of grain size on sorption of (3)H(+) and (36)Cl(-) was negligible. Retardation and distribution coefficients of both tracers converged to one and zero, respectively, in case of all fractions of crushed granite and infill material. Generally, the presumed ion exclusion of (36)Cl in anionic form was proved under given conditions, only very weak one seems to exist in a case of infill material. In principal, both radionuclides behaved as non-sorbing, conservative tracers. On the other hand, the influence of grain size on Peclet numbers value and on dispersion coefficient was observed for both crystalline materials, namely in agreement with theoretical suppositions that the values of Peclet numbers decrease with increasing grain size and values of dispersion coefficient increase.

No MeSH data available.


Related in: MedlinePlus