scholarly journals Preparing to Submit a License Application for Yucca Mountain

2005 ◽  
Author(s):  
W.J. Arthur ◽  
M.D. Voegele
2002 ◽  
Vol 757 ◽  
Author(s):  
W. L. Ebert ◽  
J. C. Cunnane ◽  
N. L. Dietz

ABSTRACTThis paper describes how the results of vapor hydration tests (VHTs) are used to model the corrosion of waste glasses exposed to humid air in the glass degradation model for total system performance assessment (TSPA) calculations for the proposed Yucca Mountain disposal system. Corrosion rates measured in VHTs conducted at 125, 150, 175, and 200°C are compared with the rate equation for aqueous dissolution to determine parameter values that are applicable to glass degradation in humid air. These will be used to determine the minimum for the range and distribution of parameter values in calculations for the Yucca Mountain disposal system license application (TSPA-LA). The rate equation for glass dissolution is rate = kE • 10 η • pH • exp(–Ea/RT). Uncertainties in the calculated rate due to the range of waste glass compositions and water exposure conditions are taken into account by using a range of values for the rate coefficient kE. The parameter values for the pH dependence (η) and temperature dependence (Ea) and the upper limit for kE are being determined with other tests. Using the values of η and Ea from the site recommendation model, the VHT results described in this paper provide a value of log kE = 5.1 as the minimum value for the rate expression. This value will change slightly if different pH-and temperature-dependencies are used for the TSPA-LA model.


Author(s):  
Jerry McNeish ◽  
Peter Swift ◽  
Rob Howard ◽  
David Sevougian ◽  
Donald Kalinich ◽  
...  

The development of a deep geologic repository system in the United States has progressed to the preparation of an application for a license from the U.S. Nuclear Regulatory Commission. The project received site recommendation approval from the U.S. President in early 2002. The next phase of the project involves development of the license application (LA) utilizing the vast body of information accumulated in study of the site at Yucca Mountain, Nevada. Development of the license application involves analyses of the total system performance assessment (TSPA) of the repository, the TSPA-LA. The TSPA includes the available relevant information and model analyses from the various components of the system (e.g., unsaturated geologic zone, engineered system (waste packaging and drift design), and saturated geologic zone) (see Fig. 1 for nominal condition components), and unites that information into a single computer model used for evaluating the potential future performance or degradation of the repository system. The primary regulatory guidance for the repository system is found in 10 CFR 63, which indicates the acceptable risk to future populations from the repository system. The performance analysis must be traceable and transparent, with a defensible basis. The TSPA-LA is being developed utilizing state-of-the-art modeling software and visualization techniques, building on a decade of experience with such analyses. The documentation of the model and the analyses will be developed with transparency and traceability concepts to provide an integrated package for reviewers. The analysis relies on 1000’s of pages of supporting information, and multiple software and process model analyses. The computational environment represents the significant advances in the last 10 years in computer workstations. The overall approach will provide a thorough, transparent compliance analysis for consideration by the U.S. Nuclear Regulatory Commission in evaluating the Yucca Mountain repository.


2006 ◽  
Vol 985 ◽  
Author(s):  
Timothy McCartin

AbstractThe disposal of high-level radioactive wastes in a potential geologic repository at Yucca Mountain, Nevada is governed by the U.S. Environmental Protection Agency (EPA) standards and U.S. Nuclear Regulatory Commission (NRC) regulations. The EPA has the responsibility for setting public health and safety and environmental standards for radioactive waste disposal at Yucca Mountain and it is the NRC's responsibility to implement those standards in its regulations to ensure public health and safety and the environment are protected. The U.S. Department of Energy (DOE), as the developer of the potential repository, must submit a license application to the NRC to seek approval to construct the repository. DOE must comply with NRC's regulations for NRC to authorize construction and license operation of a potential repository at Yucca Mountain. In 2005, EPA issued proposed revised standards and NRC issued proposed revised regulations for conducting performance assessment beyond 10,000 years up to 1 million years. The challenge for the EPA and NRC is to develop standards and regulations that provide an appropriate method for evaluating the safety of the potential repository given the unprecedented time period to be analyzed and the inherent uncertainties in estimating the future evolution of the Yucca Mountain site and the containment of the waste in the waste packages. A fundamental aspect of the proposed EPA standard is the specified approach for limiting undue speculation on future behavior of the site by constraining the features, events, and processes that need to be considered in the performance assessment. EPA proposed to limit the assessment of specific features, events, and processes in the period after 10,000 years to effects on the repository system that are most relevant (i.e., ignoring lesser or secondary effects that may add to speculation and uncertainties but would not be expected to have a significant effect on peak dose over a 1 million year period). For example, DOE's performance assessment may (1) limit the analysis of seismic activity to the effects caused by damage to the drifts and the waste package; (2) limit analysis of igneous activity to effects on the waste package that result in release of radionuclides to the atmosphere or ground water; (3) require DOE to include general corrosion in its analysis of engineered barrier performance, and (4) limit the effect of climate variation to those resulting from increased water flowing to the repository. NRC has been reviewing its performance assessment models and techniques to assure they are consistent with EPA's proposed requirements for the period after 10,000 years and adequate to assist the review of a potential license application from the DOE. Currently, only slight modifications to the models and approaches used in the performance assessment for the initial 10,000 years are expected to be needed to accommodate calculations for longer times (e.g., modifications to implement a steady-state value to represent the proposed climate change). NRC staff will be able to use the modified performance assessment to identify additional sensitivities associated with estimating doses over very long time periods and improve its understanding of the performance of a potential repository at Yucca Mountain.


2010 ◽  
Vol 117 (1-4) ◽  
pp. 7-25 ◽  
Author(s):  
Sharad Kelkar ◽  
Mei Ding ◽  
Shaoping Chu ◽  
Bruce A. Robinson ◽  
Bill Arnold ◽  
...  

2010 ◽  
Vol 73 ◽  
pp. 194-202 ◽  
Author(s):  
Evaristo J. Bonano ◽  
David S. Kessel ◽  
Lori J. Dotson

For more than 30 years Sandia National Laboratories (SNL) has played a key role in the development and implementation of total system analyses of waste management systems in the United States. Two very important applications have been the total system analysis of long term performance that supported (1) the Compliance Certification Application (CCA) for the Waste Isolation Pilot Plant (WIPP) in 1996 and (2) the License Application (LA) for the Yucca Mountain (YM) Repository in 2008.


1999 ◽  
Vol 556 ◽  
Author(s):  
T. A. Buscheck ◽  
J. Gansemer ◽  
J. J. Nitao ◽  
T. H. Delorenzo

AbstractA multi-scale, thermohydrologic (TH) modeling methodology has been developed that integrates the results from 1-, 2-, and 3-D drift-scale models and a 3-D mountain-scale model to calculate the near-field TH variables affecting the performance of the engineered barrier system (EBS) of the potential repository at Yucca Mountain. This information was used by Total System Performance Assessment—Viability Assessment (TSPA-VA) and is being used by the ongoing TSPA, supporting the License Application Design Selection, to assess waste-package (WP) corrosion, waste-form dissolution, and radionuclide transport in the EBS. Line-load WP spacing, which places WPs nearly end to end in widely spaced drifts, results in more locally intensive and uniform heating along drifts, causing hotter, drier, and more uniform conditions on WPs than point-load spacing, which is used in the VA design. Backfilling drifts with a granular material with coarse, well-sorted, nonporous grains (e.g., a coarse quartz sand) results in a large, persistent reduction in RH on WPs; point-load spacing allows only the medium-to-high-heat-output WPs to benefit from RH reduction, but line-load spacing enables all WPs to benefit.


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