Evaluation of groundwater flow and transport at the Shoal underground nuclear test: An interim report

Pohll, Greg; Chapman, Jenny; Hassan, Ahmed E.; Papelis, Charalambos; Andričević, Roko; Shirley, Craig

doi:10.2172/656462

Cited by 24 publications

(67 citation statements)

References 40 publications

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“…The numerical flow and transport model previously developed for the Shoal site (Pohll et al, 1998) was used to identify the nine uncertain parameters considered in the analysis. These parameters were presented in the CAIP and are as follows: effective porosity, hydraulic head at the downgradient boundary, recharge, hydraulic conductivity, fracture connectivities, fracture orientations, fracture dip, glass dissolution rate, and retardation.…”

Section: Rationale For Proposed Activities: Results Of the Data Decismentioning

confidence: 99%

Addendum to the Corrective Action Investigation Plan for Corrective Action Unit 447, Project Shoal Area, Nevada Subsurface Site, Revision 1, April 1999

Nv¹

1999

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Section: Rationale For Proposed Activities: Results Of the Data Decismentioning

confidence: 99%

Addendum to the Corrective Action Investigation Plan for Corrective Action Unit 447, Project Shoal Area, Nevada Subsurface Site, Revision 1, April 1999

Nv¹

1999

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“…These studies provide primarily qualitative insight into the affinity of radionuclides for carbonate material; they do not represent specific NTS material or water chemistry. Pohll et al (1998) report sorption studies on granite in support of the Project Shoal investigation.…”

Section: Measured K D Valuesmentioning

confidence: 99%

“…Section 9.0 Table 9-11 Note: Ca, Sr estimated to have no sorption on granite; Am, Eu, Sm, Pu, Np estimated to be strongly sorbing, analogous to Pb (Pohll, 1998) a K d ranges assigned based on similarity to TCA unit for which estimates based upon stratigraphy were reported by Zavarin et al (2002) b K d ranges assigned based on similarity to CHCU unit for which estimates based upon stratigraphy were reported by Zavarin et al (2002) c K d ranges assigned based on similarity to BA unit for which estimates based upon stratigraphy were reported by Zavarin et al (2002) Note -For Pu, oxygen fugacities of 1E-5, 1E-10, and 1E-15 are considered as they affect the speciation and valence of Pu. …”

Section: Contaminant Transport Parameters For Caus 101 and 102mentioning

confidence: 99%

Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada, Revision 0

Drici¹

2003

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“…Given this, radionuclides are not expected to exit the cavity and begin transport through the aquifer until after infilling is completed. At some underground nuclear test sites, the infill process has required decades, and this time has been accounted for in radioactive decay of the source (Pohll et al, 1998;Pohlmann et al, 1999). Estimated cavity infill times for Amchitka are relatively short by comparison, predicted to be 500 days for Milrow based on subsurface hydrologic data (USGS, 1970), and 290 days for Cannikin, based on the time of infilling of Cannikin Lake within the collapse sink (Gonzalez, 1977).…”

Section: Release Ratementioning

confidence: 99%

Modeling Groundwater Flow and Transport of Radionuclides at Amchitka Island's Underground Nuclear Tests: Milrow, Long Shot, and Cannikin

Hassan¹,

Pohlmann²,

Chapman³

2002

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EXECUTIVE SUMMARYThe groundwater flow and radionuclide transport at the Amchitka Island underground nuclear tests are modeled using two-dimensional numerical simulations. A multi-parameter uncertainty analysis is adapted and used to address the effects of the uncertainties associated with the definition of the modeled processes and the values of the parameters governing these processes. The nuclear tests performed at Milrow, Long Shot and Cannikin are the focus of this investigation. These tests were detonated on October 2, 1969, October 29, 1965, and November 6, 1971, respectively. The announced yield of these test are approximately one megaton for Milrow, 80 kilotons for Long Shot and less than five megatons for Cannikin.The flow model is conceptualized to address the problem of density-driven flow where the saltwater intrusion problem is encountered. The multi-parameter uncertainty analysis addresses the effects of the uncertainty associated with four of the parameters governing these processes on the resulting solution. These parameters are the hydraulic conductivity, recharge, fracture porosity and macrodispersivity. The heat-driven flow and three-dimensional flow features are addressed in a less rigorous manner via a sensitivity analysis. This includes the geothermal heat, the shot-induced heat effects, the chimney geometry, the effects of nearby faults and the effect of the island half-width. All the simulations presented in this report, as well as the sensitivity analyses, are performed using the FEFLOW model of the WASY Institute for Water Resources Planning and Systems Research Ltd.The conceptual transport model simulates many processes in addition to the advection-dispersion process. The release mechanism and glass dissolution, sorption effects, matrix diffusion and radioactive decay are among the processes modeled. The parametric uncertainty analysis also extends to three of the transport parameters governing the glass dissolution process, the matrix diffusion process and local scale dispersion. The solution of the transport problem is performed using a numerical particle-tracking algorithm and a semi-analytical solution is used for the matrix diffusion studies.Hydraulic conductivity data collected from six boreholes are analyzed to yield a best estimate for the homogeneous conductivity value and the range of uncertainty associated with this estimate. Temperature logs measured in several of the boreholes on the island are used to estimate groundwater recharge. Measurements of total porosity were made on numerous core samples obtained from four boreholes. There are no measurements for fracture porosity, and therefore, values for this parameter are selected based on reported values from the literature.Batch sorption experiments were performed using cores collected from the Cannikin emplacement well. Sorption on both basalt and breccia was investigated for strontium, cesium, and lead dissolved in water of basically seawater composition. The high ionic strength of the solution and rock properties resulte...

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Evaluation of groundwater flow and transport at the Shoal underground nuclear test: An interim report

Cited by 24 publications

References 40 publications

Addendum to the Corrective Action Investigation Plan for Corrective Action Unit 447, Project Shoal Area, Nevada Subsurface Site, Revision 1, April 1999

Addendum to the Corrective Action Investigation Plan for Corrective Action Unit 447, Project Shoal Area, Nevada Subsurface Site, Revision 1, April 1999

Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada, Revision 0

Modeling Groundwater Flow and Transport of Radionuclides at Amchitka Island's Underground Nuclear Tests: Milrow, Long Shot, and Cannikin

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