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Category : Alpha-bearing wastes
Languages : en
Pages :
Book Description
Preliminary Performance Assessment of the Greater Confinement Disposal Facility at the Nevada Test Site
Author: Preliminary Performance Assessment of a Nevada Test Site Waste
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 18
Book Description
The performance of the Nevada Test Site Greater Confinement Disposal (GCD) site was assessed against the Environmental Protection Agency's (EPA) requirements for disposal of high-level waste, spent fuel and transuranic waste, 40 CFR Part 191. No new data were collected for this assessment. This preliminary assessment indicates that the GCD concept is a viable method of disposing of transuranic wastes. The results are being used to direct future site characterization activities. 6 refs., 3 figs., 2 tabs.
Second Performance Assessment Iteration of the Greater Confinement Disposal Facility at the Nevada Test Site
Author: Performance Assessment of the Greater Confinement Disposal Facility on the Nevada Test Site
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 11
Book Description
A small amount of transuranic (TRU) waste has been disposed of at the Greater Confinement Disposal (GCD) site located on the Nevada Test Site's (NTS) Radioactive Waste Management Site (RWMS). The waste has been buried in several deep (37 m) boreholes dug into the floor of an alluvial basin. For the waste to remain in its current configuration, the DOE must demonstrate compliance of the site with the TRU disposal requirements, 40 CFR 191. Sandia's approach to process modelling in performance assessment is to use demonstrably conservative models of the site. Choosing the most conservative model, however, can be uncertain. As an example, diffusion of contaminants upward from the buried waste in the vadose zone water is the primary mechanism of release. This process can be modelled as straight upward planar diffusion or as spherical diffusion in all directions. The former has high fluxes but low release areas, the latter has lower fluxes but is spread over a greater area. We have developed analytic solutions to a simple test problem for both models and compared the total integrated discharges. The spherical diffusion conceptual model results in at least five times greater release to the accessible environment than the planar model at all diffusivities. Modifying the planar model to allow for a larger release, however, compensated for the smaller original planar discharge and resulted in a new planar model that was more conservative that the spherical model except at low diffusivities.
Waste Inventory and Preliminary Source Term Model for the Greater Confinement Disposal Site at the Nevada Test Site
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 120
Book Description
Currently, there are several Greater Confinement Disposal (GCD) boreholes at the Radioactive Waste Management Site (RWMS) for the Nevada Test Site. These are intermediate-depth boreholes used for the disposal of special case wastes, that is, radioactive waste within the Department of Energy complex that do not meet the criteria established for disposal of high-level waste, transuranic waste, or low-level waste. A performance assessment is needed to evaluate the safety of the GCD site, and to examine the feasibility of the GCD disposal concept as a disposal solution for special case wastes in general. This report documents the effort in defining all the waste inventory presently disposed of at the GCD site, and the inventory and release model to be used in a performance assessment for compliance with the Environmental Protection Agency's 40 CFR 191.
Preliminary Evaluation of the Use of the Greater Confinement Disposal Concept for the Disposal of Fernald 11e(2) Byproduct Material at the Nevada Test Site
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Category :
Languages : en
Pages :
Book Description
This report documents a preliminary evaluation of the ability of the greater confinement disposal boreholes at the Nevada Test Site to provide long-term isolation of radionuclides from the disposal of vitrified byproduct material. The byproduct material is essentially concentrated residue from processing uranium ore that contains a complex mixture of radionuclides, many of which are long-lived and present in concentrations greater than 100,000 picoCuries per gram. This material has been stored in three silos at the fernald Environmental Management Project since the early 1950s and will be vitrified into 6,000 yd[sup 3] (4,580 m[sup 3]) of glass gems prior to disposal. This report documents Sandia National Laboratories' preliminary evaluation for disposal of the byproduct material and includes: the selection of quantitative performance objectives; a conceptual model of the disposal system and the waste; results of the modeling; identified issues, and activities necessary to complete a full performance assessment.
Completion of the Transuranic Greater Confinement Disposal Borehole Performance Assessment for the Nevada Test Site
Author: Preliminary Identification of Potentially Disruptive Scenarios at the Greater Confinement Disposal Facility, Area 5 of the Nevada Test Site
Author: R. V. GuzowskiPerformance Assessment Methodology as Applied to the Greater Confinement Disposal Site
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 11
Book Description
The US Department of Energy has contracted Sandia National Laboratories to conduct a performance assessment of the Greater Confinement Disposal facility, Nevada. The performance assessment is an iterative process in which transport models are used to prioritize site characterization data collection. Then the data are used to refine the conceptual and performance assessment models. The results of the first two performance assessment iterations indicate that the site is likely to comply with the performance standards under the existing hydrologic conditions. The third performance iteration expands the conceptual model of the existing transport system to include possible future events and incorporates these processes in the performance assessment models. The processes included in the third performance assessment are climate change, bioturbation, plant uptake, erosion, upward advection, human intrusion and subsidence. The work completed to date incorporates the effects of bioturbation, erosion and subsidence in the performance assessment model. Preliminary analyses indicate that the development of relatively deep-rooting plant species at the site, which could occur due to climate change, irrigated farming or subsidence, poses the greatest threat to the site's performance.
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