Assessing field-scale migration of radionuclides at the Nevada Test Site: “mobile” species

Hu, Qinhong; Rose, Timothy P.; Zavarin, Mavrik; Smith, David K.; Moran, J. E.; Zhao, Pihong

doi:10.1016/j.jenvrad.2008.06.007

Cited by 31 publications

(18 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a similar vein Hu and Smith (2004) and Hu et al (2008) reported that technetium released during atomic weapons testing behaved less conservatively than expected. In these cases, as well as for those involving soil studies, the importance of microenvironments, in which the local redox state is much different than that surrounding it, is clearly an important consideration that needs to be addressed before overly-conservative models of technetium mobility in the environment are fashioned.…”

Section: Introductionmentioning

confidence: 66%

“…The relatively rapid re-oxidation in laboratory experiments appears to contrast to field 9.2 investigations in which technetium remains in the relatively immobile Tc(IV) state. Development of microenvironments, in which the oxidation state on the local scale contrasts with that of the surrounding, general state, has been discussed in the literature (Hu and Smith 2004;Hu et al 2008), but experimental evidence for how these conditions evolve are lacking. Carefully conducted laboratory experiments coupled with field studies and computer modeling may elucidate the evolution of such microenvironments.…”

Section: Discussion and Recommendations For Future Studiesmentioning

confidence: 99%

See 1 more Smart Citation

The Geochemistry of Technetium: A Summary of the Behavior of an Artificial Element in the Natural Environment

Icenhower¹,

Qafoku²,

Martin³

et al. 2008

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 66%

Section: Discussion and Recommendations For Future Studiesmentioning

confidence: 99%

The Geochemistry of Technetium: A Summary of the Behavior of an Artificial Element in the Natural Environment

Icenhower¹,

Qafoku²,

Martin³

et al. 2008

View full text Add to dashboard Cite

“…3). In addition to high levels of tritium (up to 5 Â 10 7 Bq/L), low-levels of other radionuclides have been detected Hu et al 2008). Low concentrations of Pu were detected in several of these wells (Table 1), which will be described in some detail below.…”

Section: Plutonium Detected In Nts Groundwatermentioning

confidence: 91%

“…Most recently, the effort has been led by the Underground Test Area project, Department of Energy, National Nuclear Security Administration, Nevada Operations Office, U.S.A. Details regarding sampling programs and groundwater characterization can be found in Smith (1995), Tompson et al (2002), andHu et al (2008). The focus of this chapter is the observation and characterization of plutonium transport mechanisms at the NTS.…”

Section: Introductionmentioning

confidence: 99%

Colloid-Facilitated Transport of Plutonium at the Nevada Test Site, NV, USA

Kersting

Zavarin

2011

Actinide Nanoparticle Research

View full text Add to dashboard Cite

Increasing observations of subsurface actinide transport has reinforced the need for a basic geochemical and hydrologic understanding of how these contaminants are transported in groundwater. At the Nevada Test Site, NV, USA, low-levels of plutonium have been shown to migrate on the scale of kilometers. At all but one sampling location the Pu is associated with the colloidal fraction (<1 mm) consisting predominantly of clays and zeolites. The majority of the Pu ($70%) is associated with the smallest nanoparticle (e.g., colloid) size fraction of 10-100 nm and in one case was identified as associated with a clay colloid. At one unique sampling site, Pu is predominantly associated with dissolved organic matter. Monitoring at over 20 contaminated groundwater sites at the NTS suggests that low-levels of Pu can be mobilized either via colloid-facilitated transport in fractured rock or as a result of aqueous Pu stabilization by anthropogenic levels of dissolved organic matter. Nevertheless, activities above the EPA's Maximum Contaminant Level (MCL) for alpha-emitting radionuclides (15 pCi/L, 0.56 Bq/L) have been measured at only two locations at the NTS.

show abstract

“…Many studies of transport therefore are motivated by issues related to the storage of highlevel nuclear waste and utilize highly characterized model waste forms. The migration of actinides at historical test sites has been relatively well studied [1,4,[12][13][14][15] compared with the limited literature on the parameters that may affect the relative mobility of actinides and fission products in vitrified, macro-scale debris [16][17][18]. An understanding of the specific melt glass forms produced by underground and near-surface weapons testing is important for prediction and remediation of contaminant plumes at sites where nuclear testing has occurred.…”

Section: Introductionmentioning

confidence: 99%

Chemical speciation of U, Fe, and Pu in melt glass from nuclear weapons testing

Pacold

Lukens

Booth

et al. 2016

Journal of Applied Physics

View full text Add to dashboard Cite

Nuclear weapons testing generates large volumes of glassy material that influence the transport of dispersed actinides in the environment and may carry information on the composition of the detonated device. We determine the oxidation state of U and Fe (which is known to buffer the oxidation state of actinide elements and to affect the redox state of groundwater) in samples of melt glass collected from three U.S. nuclear weapons tests. For selected samples, we also determine the coordination geometry of U and Fe, and we report the oxidation state of Pu from one melt glass sample. We find significant variations among the melt glass samples, and in particular, find a clear deviation in one sample from the expected buffering effect of Fe(II)/Fe(III) on the oxidation state of uranium. In the first direct measurement of Pu oxidation state in a nuclear test melt glass, we obtain a result consistent with existing literature that proposes Pu is primarily present as Pu(IV) in post-detonation material. In addition, our measurements imply that highly mobile U(VI) may be produced in significant quantities when melt glass is quenched rapidly following a nuclear detonation, though these products may remain immobile in the vitrified matrices. The observed differences in chemical state among the three samples show that redox conditions can vary dramatically across different nuclear test conditions. The local soil composition, associated device materials, and the rate of quenching are all likely to affect the final redox state of the glass. The resulting variations in glass chemistry are significant for understanding and interpreting debris chemistry, and the later environmental mobility of dispersed material.

show abstract

Assessing field-scale migration of radionuclides at the Nevada Test Site: “mobile” species

Cited by 31 publications

References 65 publications

The Geochemistry of Technetium: A Summary of the Behavior of an Artificial Element in the Natural Environment

The Geochemistry of Technetium: A Summary of the Behavior of an Artificial Element in the Natural Environment

Colloid-Facilitated Transport of Plutonium at the Nevada Test Site, NV, USA

Chemical speciation of U, Fe, and Pu in melt glass from nuclear weapons testing

Contact Info

Product

Resources

About