Quality Assurance Services

The Nevada System of Higher Education (NSHE) Quality Assurance (QA) Program provides a full range of affordable QA services including records management, document and data control, training, and auditing. The program was regularly audited by the United States Department of Energy (DOE) to ensure strict compliance to regulatory requirements for nuclear facilities. The NSHE QA Program is staffed by knowledgeable professionals who specialize in assisting smaller organizations who have no previous quality assurance experience

Task 3: Quality assurance program

The University and Community College System of Nevada (UCCSN) is qualified as a supplier of scientific and engineering studies as well as software development. Quality Assurance Procedures (QAPs) comprise the upper tier of the UCCSN QA Program, written in accordance with QAP-2.0, “Quality Assurance Program – Preparation, Approval, and Revision of Procedures”, to meet the requirements of DOE/RW-0333P, OCRWM Quality Assurance Requirements and Description (QARD). The UCCSN Quality Assurance Requirements Matrix is provided to DOE specifying where in the QAPs OCRWM QA requirements are met, as well as exceptions to the QARD, due to scope of work

Thermochronological evolution of calcite formation at the potential Yucca Mountain repository site, Nevada: Part 2 fluid inclusion analyses and UPb dating

The presence of two-phase fluid inclusions in thin secondary mineral crusts at the potential Yucca Mountain nuclear waste repository has raised questions regarding the origin, timing, and temperature of past fluid flow through the repository horizon. The geologically recent passage of fluids with high temperatures would call into question the suitability of the site for the storage of high level nuclear waste. This study determined the thermal history of fluid flow through the site using fluid inclusion analyses and constrained the timing of thermal fluids by dating silica minerals spatially associated with the fluid inclusions using U-Pb techniques. Results provide a detailed time-temperature history of fluid migration through primary and secondary pore spaces during the past 8 to 9 million years. One hundred and fifty-five samples were collected in the unsaturated zone from the C-shaped Exploratory Studies Facility (ESF), the ECRB cross drift which crosses the potential repository horizon, and exploratory alcoves. Detailed petrographic and paragenetic studies indicated that the oldest secondary minerals consisted of heterogeneously distributed calcite with lesser chalcedony, quartz, opal, and fluorite. The oldest secondary minerals were overgrown by intermediate bladed calcite. The youngest secondary minerals include chemically distinct Mgenriched, growth-zoned sparry calcite (MGSC) and intergrown U-enriched opal. Fluid inclusion petrography indicated that 50 % of the samples (n = 78) contained fluid inclusion assemblages with two-phase fluid inclusions, and that assemblages of liquid-only fluid inclusions represent \u3e 96% of all fluid inclusions within the secondary minerals. Assemblages of two-phase inclusions also contain liquid-only inclusions that did not nucleate a vapor-bubble owing to formation at relatively low temperatures. Virtually all two-phase fluid inclusions occur in paragenetically old calcite; rare two-phase inclusion assemblages were observed in old fluorite (n = 3) and quartz (n = 2). Rare two-phase fluid inclusions were observed in early-intermediate calcite; sparse, irregularly shaped liquid-only inclusions form the only fluid inclusion assemblages observed in late-intermediate minerals and young MGSC. Homogenization temperatures for calcite across the site are generally 45 - 60 °C, but higher temperatures reaching 83 °C were recorded in the north portal and ramp of the ESF and cooler temperatures of ~ 35 - 45 °C were recorded in the intensely fracture zone. Samples from lithophysal cavities in the ESF and ECRB contain multiple populations of two-phase inclusions. Inclusion temperatures are highest in early calcite (\u3e 45 °C) and cooler in paragenetically younger early calcite, indicating cooling with time. The cooler temperatures coincide with temperatures recorded in the intensely fractured zone and indicate that secondary minerals in the intensely fractured zone began to precipitate later than secondary minerals in other locations. Freezing point depressions determined for inclusions range from -0.2 to -1.6 °C indicating trapping of a low salinity fluid. A small number of fluid inclusions in fluorite and quartz were identified and evaluated. Four inclusions in these minerals homogenized at temperatures higher than those recorded for calcite (91 ° - 95 °C) . Two approaches were used to constrain the timing of thermal fluids at Yucca Mountain. First, the age of MGSC was determined, and it provides a minimum age for fluids with elevated temperatures owing to the presence of only liquid-only inclusions in MGSC. Results indicate that MGSC began to precipitate across the site between 2.90 ± 0.06 Ma and about 1.95 ± 0.06 Ma, and MGSC has continued to precipitate to within the last half million years. These ages constrain fluids with elevated temperatures to have accessed the site more than about 2.90 Ma. Second, more precise temporal constraints were determined for samples in which datable opal or chalcedony occur in the intermediate or older parts of the mineral crusts, or are spatially related to 2-phase fluid inclusions. Such ages indicate that two-phase fluid inclusions are older than 5.32 ± 0.02 Ma, and that fluids with elevated temperatures were present at Yucca Mountain before this time. Results from this study are consistent with a model of descending meteoric water that infiltrated the cooling tuff sequence, became heated, and precipitated secondary minerals within the vadose zone. Fluid inclusions indicate that fluids with elevated temperatures were present during the early history of Yucca Mountain. Sparse, liquid-only fluid inclusions in late intermediate to young calcite indicate that secondary minerals were precipitated from low temperature fluids during the past 5 million years. This study demonstrates that the hypothesis of geologically recent upwelling hydrothermal fluids is untenable and should not disqualify Yucca Mountain as a potential nuclear waste storage site

Determining the Redox Properties of Yucca Mountain-Related Groundwater Using Trace Element Speciation for Predicting the Mobility of Nuclear Waste

The objective of this task is to determine the principal oxidation state (redox) species of select elements in samples of groundwater in the vicinity of Yucca Mountain (YM), which is being evaluated as a site for geologic storage of the nation’s spent nuclear fuel and high-level nuclear waste. Samples to be analyzed include, but are not limited to, groundwater from wells of the Nye County Early Warning Drilling Program. Elements to be studied include arsenic (As), antimony (Sb), selenium (Se), chromium (Cr), manganese (Mn), iron (Fe), copper (Cu), molybdenum (Mo), vanadium (V), tungsten (W), rhenium (Re), and uranium (U). The purpose is to develop a more accurate and complete description of the redox properties of YM-related groundwater, which influences the solubility and consequently the transport of radionuclides. Indeed, a possible natural barrier to radionuclide migration in the saturated zone (SZ) is the presence of non-oxidizing or reducing environments. For example, the mobility of Tc-99 in oxic groundwater, ascribed to the pertechnetate ion, is greatly diminished in reducing groundwater. The containment of radionuclides away from the accessible environment is a key feature in the Yucca Mountain performance assessment

Yucca Mountain Saturated Zone Carbon-14

This Scientific Investigation Plan (SIP) provides an overview of the work described in “Yucca Mountain Saturated Zone Carbon-14”, a proposal funded by the U.S. Department of Energy’s (DOE) Office of Repository Development under the UCCSN/YMP Co-op in support of the Science and Technology Initiatives. The objective of this work is to provide improved estimates of the time required for ground water to travel from the site of the proposed high-level radioactive waste repository at Yucca Mountain, Nevada, to the accessible environment

Direct analysis of solid corrosion products by laser ablation ICP-MS: Method development and the interaction of aqueous uranium, gadolinium and neodymium with Iron Shot and Iron (III) Oxide

The purpose of this report is to summarize the work and present conclusions of Project Activity Task ORD-RF-03 conducted under cooperative agreement number DE-FC28-04RW12237 between the U.S. Department of Energy and the Nevada System of Higher Education (NSHE). The work was conducted in the Harry Reid Center for Environmental Studies of the University of Nevada Las Vegas from October 1, 2004 to September 30, 2006. The purpose of the study was to develop a method using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for the direct analysis of iron corrosion products, to evaluate its capabilities, advantages, and limitations, and to apply the method to examine the interaction of actinides, and other elements relevant to the long-term geologic storage of nuclear waste, with iron corrosion products. The desired quantification is for specific (targeted) sections of the surface; elemental ratios can be determined from the data if of interest

Groundwater characterization at Yucca Mountain task 2: Surface complexation and solid phase sorption

The purpose and scope of this report is to present an overview of the experiments, methods, results, and conclusions from research performed for the project “Groundwater Characterization at Yucca Mountain Task 2: Surface Complexation and Solid Phase Dissolution”. The impact of surface complexation, alteration phase formation, and solution competition with metal ions on the solubility and speciation of actinide elements (U, Pu, Np) will be examined. In particular the role of iron (as Fe2+ and Fe3+) and silicate (as SO3 2-) concentrations on speciation, solubility, sorption, and secondary phase formation of actinides will be investigated. While a large body of literature exists on the interaction of actinides with iron and iron oxide phases, relatively little has been explored regarding the impact of silicates on actinide speciation. Therefore the role of silicates will be the main focus of the report, as it is the primary factor which meaningfully contributes to the enhanced understanding of actinide environmental speciation. The described topics are examined through two main studies areas: formation of precipitates from solution phase species and sorption of dissolved species to solids. The main actinide ion species of interests are UO2 2+, NpO2 +, and Pu4+. These species were selected based on their importance as components of spent nuclear fuel and their potential to form soluble species. The main component of spent nuclear fuel is uranium; neptunium is expected to have a high solubility due to its pentavalent oxidation state, and plutonium may form colloidal species [1]. The aqueous phase pH, Fe concentration, and SiO3 2- concentration are varied. The role of Fe is of importance since canister corrosion may elevate aqueous levels of iron. Since the groundwater near the Yucca Mountain site is approaching saturation in silicate concentration, evaluation of this anion is deemed crucial. Furthermore, geochemical research at the Nevada Test Site has identified goethite and silicates as important geominerals, offering further motive for the investigation of iron oxides and silicates [2]. The role of pH is fundamental in dictating actinide and iron hydrolysis [3] and is evaluated to ascertain its importance in speciation in the presence of the other solution constituents. The project results will elucidate the relative importance of Fe and silicates in actinide speciation, in particular the formation of precipitates and subsequently sorbed species. The main focus will be on the role of silicate

Groundwater Flow and Thermal Modeling to Support a Preferred Conceptual Model for the Large Hydraulic Gradient North of Yucca Mountain

This task will create a two-dimensional, saturated zone, vertical cross-section model of groundwater flow and thermal transport through the large hydraulic gradient (LHG). This model is referenced herein as the thermal model. The scope of this study is limited to presenting a postulated hydrogeologic configuration of the LHG. The conceptualization will include the use of postulated hydrogeologic structures and material properties. The thermal model will be spatially limited to the area immediately upgradient and downgradient of the LHG and will not reproduce the many hydrogeologic features of the existing regional and site-scale models. The thermal model will be orientated north to south, approximately along a saturated zone streamline. The results of the thermal modeling will be compared to temperature data reported for site wells by the U.S. Geological Survey (USGS) and in peer-reviewed journals. Most, if not all, of this reported data is non- qualified. This task will not qualify the reported data and the reported data will be used only as a basis of comparison for the model simulations

Influence of lithophysal geometry on the uniaxial compression of tuff-like rock

The purpose of this report is to summarize the work and present conclusions of Project Activity Task ORD-FY04-013 conducted under Cooperative Agreement No. DEFC28- 04RW12232 between the U.S. Department of Energy and the Nevada System of Higher Education (NSHE). This document describes results of laboratory testing on analog lithophysal tuff (Hydro-StoneTB®) conducted in the Department of Civil and Environmental Engineering of the University of Nevada at Las Vegas (UNLV) from 2004 to 2006

Seismicity in the vicinity of Yucca Mountain, Nevada, for the period October 1, 2004 to September 30, 2006

This report describes earthquake activity within approximately 65 km of Yucca Mountain site during the October 1, 2004 to September 30, 2006 time period (FY05-06). The FY05-06 earthquake activity will be compared with the historical and more recent period of seismic activity in the Yucca Mountain region. The relationship between the distribution of seismicity and active faults, historical patterns of activity, and rates of earthquakes (number of events and their magnitudes) are important components in the assessment of the seismic hazard for the Yucca Mountain site. Since October 1992 the University of Nevada has compiled a catalog of earthquakes in the Yucca Mountain area. Seismicity reports have identified notable earthquake activity, provided interpretations of the seismotectonics of the region, and documented changes in the character of earthquake activity based on nearly 30 years of site-characterization monitoring. Data from stations in the seismic network in the vicinity of Yucca Mountain is collected and managed at the Nevada Seismological Laboratory (NSL) at the University of Nevada Reno (UNR). Earthquake events are systematically identified and cataloged under Implementing Procedures developed in compliance with the Nevada System of Higher Education (NSHE) Quality Assurance Program. The earthquake catalog for FY05-06 in the Yucca Mountain region submitted to the Yucca Mountain Technical Data Management System (TDMS) forms the basis of this report