A Non-Electrostatic Surface Complexation Approach to Modeling Radionuclide Migration at the Nevada Test Site: I. Iron Oxides and Calcite

Zavarin, Mavrik; Bruton, C.J.

doi:10.2172/15015949

Cited by 18 publications

(66 citation statements)

References 37 publications

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“…Nevertheless, Pu(IV) expresses a moderate affinity for calcite surfaces and aluminosilicate colloids. Unlike Pu(IV), Pu(V) sorption to both calcite and aluminosilicate surfaces is quite weak (Zavarin and Bruton, 2004b;. Thus, the transport behavior of Pu will be controlled in large part, by the oxidation state speciation of Pu in groundwater.…”

Section: Cnts/min --------------------------Mol/l -------------------mentioning

confidence: 99%

“…The modeling strategy is discussed in detail in and will not be repeated here. Sorption to matrix minerals (calcite/dolomite) and aqueous speciation was accomplished directly in the CRUNCH code based on surface complexation, ion exchange, and aqueous speciation thermodynamic parameters and mineral characteristics reported in (Zavarin and Bruton, 2004a;Zavarin and Bruton, 2004b;Zavarin et al, 2004). Sorption to colloids was implemented using colloid characteristics combined with surface complexation reactions.…”

Section: Modeling Approachmentioning

confidence: 99%

“…The time of the tracer injection pulse was taken from Table 2.5. Aqueous complexation and surface complexation reaction constants and mineral surface area/reactive site density were taken from (Zavarin and Bruton, 2004a;Zavarin and Bruton, 2004b) and (Zavarin et al, 2002). The concentration of colloid >SiOH and >AlOH reactive sites was calculated based on the colloid mineralogy, load, particle size, and a nominal reactive site density of 2.31 sites/nm 2 .…”

Section: Reactive Transport Modelingmentioning

confidence: 99%

“…At the conclusion of all effluent and post-test core analyses, the reactive transport of radionuclides in the fractures was modeled. Data were modeled using the CRUNCH code (Steefel and Yabusaki, 1995) combined with our surface complexation and ion exchange sorption database (Zavarin and Bruton, 2004a;Zavarin and Bruton, 2004b). Data were also modeled using the RELAP (REactive transport LAPlace transform inversion computer code) code.…”

Section: Introductionmentioning

confidence: 99%

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Colloid-Facilitated Radionuclide Transport in Fractured Carbonate Rock from Yucca Flat, Nevada National Security Site

Zavarin¹,

Roberts²,

Johnson³

et al. 2007

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Section: Cnts/min --------------------------Mol/l -------------------mentioning

confidence: 99%

Section: Modeling Approachmentioning

confidence: 99%

Section: Reactive Transport Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Colloid-Facilitated Radionuclide Transport in Fractured Carbonate Rock from Yucca Flat, Nevada National Security Site

Zavarin¹,

Roberts²,

Johnson³

et al. 2007

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“…Our results in the report were consistent with their findings. For U(VI), it is likely that the high dissolved inorganic carbon (DIC) plays a more important role in controlling K d than the DOC (Zavarin and Bruton 2004a;2004b).…”

Section: U(vi) Sorptionmentioning

confidence: 99%

Actinide Sorption in Rainier Mesa Tunnel Waters from the Nevada Test Site

Zhao¹,

Zavarin²,

Leif³

et al. 2007

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The sorption behavior of americium (Am), plutonium (Pu), neptunium (Np), and uranium (U) in perched Rainier Mesa tunnel water was investigated. Both volcanic zeolitized tuff samples and groundwater samples were collected from Rainier Mesa, Nevada Test Site, NV for a series of batch sorption experiments. Sorption in groundwater with and without the presence of dissolved organic matter (DOM) was investigated.Am(III) and Pu(IV) are more soluble in groundwater that has high concentrations of DOM. The sorption K d for Am(III) and Pu(IV) on volcanic zeolitized tuff was up to two orders of magnitude lower in samples with high DOM (15 to 19 mg C/L) compared to samples with DOM removed (< 0.4 mg C/L) or samples with naturally low DOM (0.2 mg C/L). In contrast, Np(V) and U(VI) sorption to zeolitized tuff was much less affected by the presence of DOM. The Np(V) and U(VI) sorption K d s were low under all conditions. Importantly, the DOM was not found to significantly sorb to the zeolitized tuff during these experiment.The concentration of DOM in groundwater affects the transport behavior of actinides in the subsurface. The mobility of Am(III) and Pu(IV) is significantly higher in groundwater with elevated levels of DOM resulting in potentially enhanced transport. To accurately model the transport behavior of actinides in groundwater at Rainier Mesa, the low actinide K d values measured in groundwater with high DOM concentrations must be incorporated in predictive transport models.

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A consistent model for estimating the partitioning of Am, Pu and Se in agricultural soils

Hormann

2021

J Radioanal Nucl Chem

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The component additive model UNiSeCs II for simulating the physicochemical behaviour of the radionuclides americium, plutonium and selenium in agricultural soils is presented. The model is validated by estimating the distribution coefficients (Kd) of these elements measured in batch experiments from the literature. For all three elements, the resulting average relative deviations from the experimental values are smaller than a factor of 2.5. This indicates that the model has the potential to significantly improve the predictions of radioecological models that normally use tabulated Kd values from the IAEA which are known to have large uncertainties. Using UNiSeCs II, the soil solution parameters most important for the partitioning of Am, Pu and Se are identified by single parameter variations.

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A Non-Electrostatic Surface Complexation Approach to Modeling Radionuclide Migration at the Nevada Test Site: I. Iron Oxides and Calcite

Cited by 18 publications

References 37 publications

Colloid-Facilitated Radionuclide Transport in Fractured Carbonate Rock from Yucca Flat, Nevada National Security Site

Colloid-Facilitated Radionuclide Transport in Fractured Carbonate Rock from Yucca Flat, Nevada National Security Site

Actinide Sorption in Rainier Mesa Tunnel Waters from the Nevada Test Site

A consistent model for estimating the partitioning of Am, Pu and Se in agricultural soils

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