Pyrite (FeS{sub 2}) is one of the most common naturally occurring minerals that is present in many subsurface environments. It plays an important role in the genesis of enriched ore deposits through weathering reactions, is the most abundant sulfide mineral in many mine tailings, and is the primary source of acid drainage from mines and waste rock piles. The pyrite oxidation reaction serves as a prototype for oxidative weathering processes with broad significance for geoscientific, engineering, and environmental applications. Mathematical modeling of these processes is extremely challenging because aqueous concentrations of key species vary over an enormous range, oxygen inventory and supply are typically small in comparison to pyrite inventory, and chemical reactions are complex, involving kinetic control and microbial catalysis. We present the mathematical formulation of a general multi-phase advective-diffusive reactive transport model for redox processes. Two alternative implementations were made in the TOUGHREACT and TOUGH2-CHEM simulation codes which use sequential iteration and simultaneous solution, respectively. The simulators are applied to reactive consumption of pyrite in (1) saturated flow of oxidizing water, and (2) saturated-unsaturated flow in which oxygen transport occurs in both aqueous and gas phases. Geochemical evolutions predicted from different process models are compared, and issues of …

An important issue for the performance of underground nuclear waste repositories is the rate of seepage into the waste emplacement drifts. A prediction of this rate is particularly complicated for the potential repository site at Yucca Mountain, Nevada, because it is located in thick, unsaturated, fractured tuff formations. Underground opening in unsaturated media might act as capillary barriers, diverting water around them. In the present work, they study the potential rate of seepage into drifts as a function of the percolation flux at Yucca Mountain, based on a stochastic model of the fractured rock mass in the drift vicinity. A variety of flow scenarios are considered, assuming present-day and possible future climate conditions. They show that the heterogeneity in the flow domain is a key factor controlling seepage rates, since it causes channelized flow and local ponding in the unsaturated flow field.

There is no discription for this report at this time.

The objectives of this three-phase project were to design, develop, and demonstrate a monitoring system capable of detecting and quantifying tritium in situ in ground and surface waters, and in water from effluent lines prior to discharge into public waterways. The tritium detection system design is based on measurement of the low energy beta radiation from the radioactive decay of tritium using a special form of scintillating optical fiber directly in contact with the water to be measured. The system consists of the immersible sensor module containing the optical fiber, and an electronics package, connected by an umbilical cable. The system can be permanently installed for routine water monitoring in wells or process or effluent lines, or can be moved from one location to another for survey use. The electronics will read out tritium activity directly in units of pico Curies per liter, with straightforward calibration. In Phase 1 of the project, we characterized the sensitivity of fluor-doped plastic optical fiber to tritium beta radiation. In addition, we characterized the performance of photomultiplier tubes needed for the system. In parallel with this work, we defined the functional requirements, target specifications, and system configuration for an in situ tritium beta detector …

The objective was to clarify from the theoretical viewpoint the mechanical, diffusional, thermodynamic and electromagnetic aspects of the decontaminations problem, by means of developing a powerful computational model to evaluate the effect of a very rapid heating regime on the on the contaminated concrete walls or slabs. The practical objective was to assess the feasibility of the microwave heating scheme envisaged and determine its suitable parameters such as power and duration. This objective was complementary to, but separate from, the chemical and nuclear aspects of long-time processes that led to the contamination and various conceivable alternative methods of decontamination which were investigated by Dr. Brian Spalding of Oak Ridge National Laboratory, with whom the start-up phase of this project was coordinated.

The HTI subsurface characterization task will use the Hanford Cone Penetrometer platform (CPP) to deploy soil sensor and sampling probes into the vadose zone/soils around AX-104 during FY-99. This Siting Plan describes activities and actions undertaken in support of CPP deployment: deployment goals, maps of the deployment sites/locations, pre-activity (siting-related) documentation tasks, a summary of activities that have been completed to date, and an estimated schedule of additional planned activities.

The objective of this study is to study waterflood problems of the type found in Morrow sandstone. The major tasks undertaken are reservoir characterization and the development of a reservoir database; volumetric analysis to evaluate production performance; reservoir modeling; identification of operational problems; identification of unrecovered mobile oil and estimation of recovery factors; and identification of the most efficient and economical recovery process.

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This report discusses the proposals to expand a court's authority to award attorneys' fees and costs in certain cases and the proposal to permit a taxpayer to collect damages for negligent collection actions by IRS agents. These provisions are covered in sections 311 and 312 of the House version and in sections 3101 and 3102 of the Senate version.

This report focus on the job training provisions of the House and Senate-passed versions of H.R. 1385.

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This report consists of campaign finance reform with a legal analysis of issue and express advocacy.

This report describes diabetes, current treatment and management, public health impact and cost, innovations in treatment, and federal spending on treatment and research.

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The purpose of this calculation is to process the cumulative distribution functions (CDFs) characterizing the temperature threshold for the onset of corrosion provided by expert elicitation and minimize the set of values to 200 points for use in WAPDEG.

This Corrective Action Investigation Plan (CAIP) has been developed in accordance with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the US Department of Energy, Nevada Operations Office (DOE/NV); the State of Nevada Division of Environmental Protection (NDEP); and the US Department of Defense (FFACO, 1996). The CAIP is a document that provides or references all of the specific information for investigation activities associated with Corrective Action Units (CAUs) or Corrective Action Sites (CASs). According to the FFACO, CASs are sites potentially requiring corrective action(s) and may include solid waste management units or individual disposal or release sites (FFACO, 1996). Corrective Action Units consist of one or more CASs grouped together based on geography, technical similarity, or agency responsibility for the purpose of determining corrective actions. This CAIP contains the environmental sample collection objectives and the criteria for conducting site investigation activities at CAU 486, the Double Tracks Radiological Safety (RADSAFE) Area (DTRSA) which is located on the Nellis Air Force Range 71North (N), west of the Tonopah Test Range (TTR). The TTR, included in the Nellis Air Force Range Complex, is approximately 255 kilometers (km) (140 miles [mi]) northwest of Las Vegas, Nevada (Figure …

The HTI subsurface characterization task will use the Hanford Cone Penetrometer platform (CPP) to deploy contaminant sensor and soil sampling probes into the vadose zone surrounding SST 241-AX-104. Closure of the resulting penetration holes may be stipulated by WAC requirements. A stand alone grouting capability deployable by the CPP has been developed. This qualification test plan defines testing of this capability to be performed at the Immobilized Low Activity Waste Disposal Complex.

The public agricultural research, education, and extension system is comprised of a nationwide network of federal and state agricultural research laboratories and departments, land grant Colleges of Agriculture, colleges of forestry and veterinary medicine, and the nationwide Cooperative Extension System. Although the basic authority to conduct agricultural research and extension programs is permanent, Congress since 1977 has provided funding authority and policy guidance for USDA's in-house research programs, and for federal support for cooperative research, higher education, and extension programs in the states, through a title contained in omnibus farm legislation. This report discusses specific pieces of such legislation and details certain agricultural and food-related appropriations.

This report describes and analyzes key issues and legislative options related to risk analysis and risk management at EPA and considers the potential impact of proposed legislative approaches on EPA's rule-making process and final regulations. The report describes the history of EPA's use of risk analysis and then summarizes and analyzes issues and legislative proposals for increasing such use. Legislative activities in the 105th Congress are described. A list of selected references and an appendix where key terms are defined conclude the report.

This report provides a side-by-side comparison of H.R. 2621 and S. 2400, as reported, 105th Congress bills that would provide the President with trade negotiating authority and accord certain resulting agreements and implementing bills expedited -- or "fast-track" -- legislative consideration.

Major segments of U.S. agriculture are experiencing declining farm income and financial difficulty. The degree of decline, however, differs among regions and commodities. In 1996, the overall farm sector experienced record high income that declined 6.7% in 1997, and is forecast to decline by another 3.6% in 1998. Several factors are responsible for the recent drop in farm income. Reduced export demand and large global supplies have reduced crop prices

A laser sampling system was attached to a Perkin Elmer Optima 3000 inductively-coupled plasma, atomic emission spectrometer that was already installed and operating in the Chemistry and Geochemistry Department at the Colorado School of Mines. The use of the spectrometer has been highly successful. Graduate students and faculty from at least four different departments across the CSM campus have used the instrument. The final report to NSF is appended to this final report. Appendices are included which summarize several projects utilizing this instrument: acquisition of an inductively-coupled plasma atomic emission spectrometer for the geochemistry program; hydrogen damage susceptibility assessment for high strength steel weldments through advanced hydrogen content analysis, 1996 and 1997 annual reports; and methods for determination of hydrogen distribution in high strength steel welds.

Six Product Removal (PR) Cans and Containers are located within the Plutonium Finishing Plant. Each can is expected to contain a maximum of 3 g of residual radioactive material, consisting mainly of plutonium isotopes. The PR Can Containers were previously authorized by HNF-SD-TP-SEP-064, Rev. 0 (Boettger 1997), for the interarea transport of up to 3 g of plutonium. The purpose of this safety evaluation for packaging is to allow the transport of six PR Cans with their Containers from the Plutonium Finishing Plant to the 233 S Evaporator Facility. This safety evaluation for packaging is authorized for use until April 29, 1999, or until the shipment is made, whichever happens first.

The Systems Engineering Management and Implementation Plan (SEMIP) for TWRS Project W-465 describes the project implementation of the Tank Waste Remediation System Systems Engineering Management Plan (TWRS SEMP), Rev. 1. The SEMIP outlines systems engineering (SE) products and processes to be used by the project for technical baseline development. A formal graded approach is used to determine the products necessary for requirements, design, and operational baseline completion. SE management processes are defined, and roles and responsibilities for management processes and major technical baseline elements are documented.