This report talks about Atmospheric Dispersal and Deposition of Tephra fron a Potential Volcanic Eruption at Yucca Mountain, Nevada

The purpose for agency action is to preclude surface entry and the location of new mining claims, subject to valid existing rights, within and surrounding the Caliente rail corridor as described in the Yucca Mountain FEIS (DOE 2002). This protective measure is needed to enhance the safe, efficient, and uninterrupted evaluation of land areas for potential rail alignments within the Caliente rail corridor. The evaluation will assist the DOE in determining, through the Rail Alignment environmental impact statement (EIS) process, whether to construct a branch rail line, and to provide support to the BLM in deciding whether or not to reserve a ROW for the rail line under the Federal Land Policy and Management Act (FLPMA). The BLM participated as a cooperating agency in preparing this EA because it is the responsible land manager and BLM staff could contribute resource specific expertise.

The purpose of this model report is to provide documentation of the conceptual and mathematical model for atmospheric dispersion and subsequent depositions of ash on the land surfaces from a potential volcano eruptions at Yucca Mountain Nevada.

The Maintenance Plan for the Performance Assessments and Composite Analyses for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada Test Site (Bechtel Nevada, 2000) requires an annual review to assess the adequacy of the performance assessments (PAs) and composite analyses (CAs) for each of the facilities, and reports the results in an annual summary report to the U.S. Department of Energy Headquarters. The Disposal Authorization Statements for the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) also require that such reviews be made and that secondary or minor unresolved issues be tracked and addressed as part of the maintenance plan (U.S. Department of Energy [DOE]). The U.S. Department of Energy National Nuclear Security Administration Nevada Site Office performed annual reviews in fiscal year (FY) 2004 by evaluating operational factors and research results that impact the continuing validity of the PA and CA results. This annual summary report presents data and conclusions from the FY 2004 review, and determines the adequacy of the PAs and CAs. Operational factors, such as the waste form and containers, facility design, waste receipts, closure plans, as well as monitoring results and research and development (R&D) activities were reviewed …

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The unsaturated zone (UZ) in Miocene-age welded tuffs at Yucca Mountain, Nevada, is under consideration as a potential site for the construction of a high-level radioactive waste repository. Secondary calcite and silica minerals deposited on fractures and in cavities in the UZ tuffs are texturally, isotopically, and geochemically consistent with UZ deposition from meteoric water infiltrating at the surface and percolating through the UZ along fractures. Nonetheless, two-phase fluid inclusions with small and consistent vapor to liquid (V:L) ratios that yield consistent temperatures within samples and which range from about 35 to about 80 C between samples have led some to attribute these deposits to formation from upwelling hydrothermal waters. Geochronologic studies have shown that calcite and silica minerals began forming at least 10 Ma and continued to form into the Holocene. If their deposition were really from upwelling water flooding the UZ, it would draw into question the suitability of the site as a waste repository.

Yucca Mountain is under study as a potential site for underground storage of high-level radioactive waste, with the principle goal being the safe isolation of the waste from the accessible environment. This paper addresses the hydrogeologic characteristics of the fault zones at Yucca Mountain, focusing primarily on the central part of the mountain where the potential repository block is located.