Download or read book Second Performance Assessment Iteration of the Greater Confinement Disposal Facility at the Nevada Test Site written by and published by . This book was released on 1994 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Greater Confinement Disposal (GCD) facility was established in Area 5 at the Nevada Test Site for containment of waste inappropriate for shallow land burial. Some transuranic (TRU) waste has been disposed of at the GCD facility, and compliance of this disposal system with EPA regulation 40 CFR 191 must be evaluated. We have adopted an iterative approach in which performance assessment results guide site data collection, which in turn influences the parameters and models used in performance assessment. The first iteration was based upon readily available data, and indicated that the GCD facility would likely comply with 40 CFR 191 and that the downward flux of water through the vadose zone (recharge) had a major influence on the results. Very large recharge rates, such as might occur under a cooler, wetter climate, could result in noncompliance. A project was initiated to study recharge in Area 5 by use of three environmental tracers. The recharge rate is so small that the nearest groundwater aquifer will not be contaminated in less than 10,000 years. Thus upward liquid diffusion of radionuclides remained as the sole release pathway. This second assessment iteration refined the upward pathway models and updated the parameter distributions based upon new site information. A new plant uptake model was introduced to the upward diffusion pathway; adsorption and erosion were also incorporated into the model. Several modifications were also made to the gas phase radon transport model. Plutonium solubility and sorption coefficient distributions were changed based upon new information, and on-site measurements were used to update the moisture content distributions. The results of the assessment using these models indicate that the GCD facility is likely to comply with all sections of 40 CFR 191 under undisturbed conditions.
Download or read book Preliminary Performance Assessment of the Greater Confinement Disposal Facility at the Nevada Test Site written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Assessment of the Greater Confinement Disposal Facility on the Nevada Test Site written by and published by . This book was released on 1993 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Some Results from the Third Performance Assessment of the Greater Confinement Disposal GCD Site at the Nevada Test Site written by and published by . This book was released on 1993 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The US Department of Energy (DOE) has disposed of a small amount of transuranic waste within the Radioactive Waste Management Site (RWMS) on the Nevada Test Site (NTS). Disposal of transuranic waste is governed by federal regulations 40 CFR 191; consequently, a performance assessment of the site is warranted to determine whether the site will comply with the requirements under 40 CFR 191. DOE has contracted with Sandia National Laboratories to perform this assessment. This report discusses some results from this assessment.
Download or read book Completion of the Transuranic Greater Confinement Disposal Borehole Performance Assessment for the Nevada Test Site written by and published by . This book was released on 2003 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Greater Confinement Disposal of High Activity and Special Case Wastes at the Nevada Test Site written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Department of Energy's Nevada Field Office has disposed of a small quantity of high activity and special case wastes using Greater Confinement Disposal facilities in Area 5 of the Nevada Test Site. Because some of these wastes are transuranic radioactive wastes, the Environmental Protection Agency standards for their disposal under 40 CFR Part 191 which requires a compliance assessment. In conducting the 40 CFR Part 191 compliance assessment, review of the Greater Confinement Disposal inventory revealed potentially land disposal restricted hazardous wastes. The regulatory options for disposing of land disposal restricted wastes consist of (1) treatment and monitoring, or (2) developing a no-migration petition. Given that the waste is already buried without treatment, a no-migration petition becomes the primary option. Based on a desire to minimize costs associated with site characterization and performance assessment, a single approach has been developed for assessing compliance with 40 CFR Part 191, DOE Order 5820.2A (which regulates low-level radioactive wastes contained in Greater Confinement Disposal facilities) and developing a no-migration petition. The approach consists of common points of compliance, common time frame for analysis, and common treatment of uncertainty. The procedure calls for conservative bias of modeling assumptions, including model input parameter distributions and adverse processes and events that can occur over the regulatory time frame, coupled with a quantitative treatment of data and parameter uncertainty. This approach provides a basis for a defensible regulatory decision. In addition, the process is iterative between modeling and site characterization activities, where the need for site characterization activities is based on a quantitative definition of the most important and uncertain parameters or assumptions.
Download or read book Compliance Assessment Document for the Transuranic Wastes in the Greater Confinement Disposal Boreholes at the Nevada Test Site Volume 2 written by and published by . This book was released on 2001 with total page 807 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Waste Inventory and Preliminary Source Term Model for the Greater Confinement Disposal Site at the Nevada Test Site written by and published by . This book was released on 1991 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book COMPLETION OF THE TRANSURANIC GREATER CONFINEMENT DISPOSAL BOREHOLE PERFORMANCE ASSESSMENT FOR THE NEVADA TEST SITE written by Angela Colarusso and published by . This book was released on 2003 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Classified transuranic material that cannot be shipped to the Waste Isolation Pilot Plant in New Mexico is stored in Greater Confinement Disposal boreholes in the Area 5 Radioactive Waste Management Site on the Nevada Test Site. A performance assessment was completed for the transuranic inventory in the boreholes and submitted to the Transuranic Waste Disposal Federal Review Group. The performance assessment was prepared by Sandia National Laboratories on behalf of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office using an iterative methodology that assessed radiological releases from the intermediate depth disposal configuration against the regulatory requirements of the 1985 version of 40 CFR 191 of the U.S. Environmental Protection Agency. The transuranic materials are stored at 21 to 37 m depth (70 to 120 ft) in large diameter boreholes constructed in the unsaturated alluvial deposits of Frenchman Flat. Hydrologic processes that affect long- term isolation of the radionuclides are dominated by extremely slow upward rates of liquid/vapor advection and diffusion; there is no downward pathway under current climatic conditions and there is no recharge to groundwater under future ''glacial'' climatic conditions. A Federal Review Team appointed by the Transuranic Waste Disposal Federal Review Group reviewed the Greater Confinement Disposal performance assessment and found that the site met the majority of the regulatory criteria of the 1985 and portions of the 1993 versions of 40 CFR 191. A number of technical and procedural issues required development of supplemental information that was incorporated into a final revision of the performance assessment. These issues include inclusion of radiological releases into the complementary cumulative distribution function for the containment requirements associated with drill cuttings from inadvertent human intrusion, verification of mathematical models used in the performance assessment, inclusion of dose calculations from collocated low-level waste in the boreholes for the individual protection requirements, further assessments of engineered barriers and conditions associated with the assurance requirements, and expansion of documentation provided for assessing the groundwater protection requirements. The Transuranic Waste Disposal Federal Review Group approved the performance assessment for Greater Confinement Disposal boreholes in 2001 and did not approve the Application of the Assurance Requirements. Remaining issues concerned with engineered barriers and the multiple aspects of the Assurance Requirements will be resolved at the time of closure of the Area 5 Radioactive Waste Management Site. This is the first completion and acceptance of a performance assessment for transuranic materials under the U.S. Department of Energy self-regulation. The Greater Confinement Disposal boreholes are only the second waste disposal configuration to meet the safety regulatory requirements of 40 CFR 191.
Download or read book Use of a Scenario development Procedure to Identify Potentially Disruptive Scenarios Greater Confinement Disposal Facility Area 5 Nevada Test Site written by and published by . This book was released on 1994 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Greater Confinement Disposal (GCD) facility includes four boreholes that contain transuranic (TRLT) waste. Presence of the TRU waste means that this facility must comply with the US Environmental Protection Agency's Environmental Radiation Protection Standards for Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Waste-Final Rule 40 CFR Part 191. To comply with the Containment Requirements of this rule, all potentially disruptive events and processes, and by implication all potentially disruptive combinations of events and processes (scenarios), must be identified for possible inclusion in performance assessments. Screening of the FEPs identified four events for scenario development: exploratory drilling for natural resources, drilling withdrawal wells, irrigation, and subsidence. Recent environmental-isotope analyses of the vadose zone suggest that radionuclide transport from the boreholes to the water table by infiltration is not a feasible transport mechanism within the time frame of regulatory concern. For this reason, the event of drilling withdrawal wells was merged with exploratory drilling for resources. The descriptions of the remaining three events were modified slightly to aid in estimation of event probabilities and consequence analyses. The three events are: exploratory drilling for resources penetrates a TRU borehole, irrigation occurs at the Radioactive Waste Management Site (RWMS), and subsidence occurs at the RWMS. Use of a logic diagram with these three events resulted in the construction of eight scenarios, including base-case (undisturbed) conditions. Screening these scenarios at this stage of scenario development was beyond the scope of this task. Based on the implementation assumptions, this scenario-development procedure produced a comprehensive set of mutually exclusive scenarios that are reproducible and auditable for use in GCD performance assessments.
Download or read book Performance Assessment Methodology as Applied to the Greater Confinement Disposal Site written by and published by . This book was released on 1994 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book 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 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book International Symposium on Proteinase Inhibitors and Biological Control 2 written by and published by . This book was released on 1990 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book written by and published by . This book was released on 1888 with total page 823 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preliminary Identification of Potentially Disruptive Scenarios at the Greater Confinement Disposal Facility Area 5 of the Nevada Test Site written by R. V. Guzowski and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book RESULTS OF THE PERFORMANCE ASSESSMENT FOR THE CLASSIFIED TRANSURANIC WASTES DISPOSED AT THE NEVADA TEST SITE written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Most transuranic (TRU) wastes are destined for the Waste Isolation Pilot Plant (WIPP). However, the TRU wastes from the cleanup of US nuclear weapons accidents are classified for national security reasons and cannot be disposed in WIPP. The US Department of Energy (DOE) sought an alternative disposal method for these ''special case'' TRU wastes and from 1984 to 1987, four Greater Confinement Disposal (GCD) boreholes were used to place these special case TRU wastes a minimum of 21 m (70 ft) below the land surface and a minimum of 200 m (650 ft) above the water table. The GCD boreholes are located in arid alluvium at the DOE's Nevada Test Site (NTS). Because of state regulatory concerns, the GCD boreholes have not been used for waste disposal since 1989. DOE requires that TRU waste disposal facilities meet the US Environmental Protection Agency's (EPA's) requirements for disposal of TRU wastes, which are contained in 40 CFR 191. This EPA standard sets a number of requirements, including probabilistic limits on the cumulative releases of radionuclides to the accessible environment for 10,000 years. The DOE Nevada Operations Office (DOE/NV) has contracted with Sandia National Laboratories (Sandia) to conduct a performance assessment (PA) to determine if the TRU waste emplaced in the GCD boreholes complies with the EPA's requirements. Sandia has completed the PA using all available information and an iterative PA methodology. This paper overviews the PA of the TRU wastes in the GCD boreholes [1]. As such, there are few cited references in this paper and the reader is referred to [1] and [2] for references. The results of the PA are that disposal of TRU wastes in the GCD boreholes easily complies with the EPA's 40 CFR 191 safety standards for disposal of TRU wastes. The PA is undergoing a DOE Headquarters (DOE/HQ) peer review, and the final PA will be released in FY2001 or FY2002.
Download or read book Nevada Test Site Experience with Greater Confinement Disposal written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: At the NTS, we consider Greater Confinement Disposal (GCD) to be a good waste management practice rather than a disposal technology. This is an important distinction because it redefines the nature of GCD. All disposal facilities operate under the principal of ''as low as reasonably achievable'' (ALARA) in reducing personnel and public exposures. ALARA is not a technology or method but a principal put into practice. We view GCD in the same manner.
