Proceeding Toward a License Application for U.S. Nuclear Waste Repository: Total System Performance Assessment Approach

2003 ◽  
Author(s):  
Jerry McNeish ◽  
Peter Swift ◽  
Rob Howard ◽  
David Sevougian ◽  
Donald Kalinich ◽  
...  
Keyword(s):  
Performance Assessment ◽  
System Performance ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Total System ◽  
License Application ◽  
Regulatory Commission ◽  
The U.S

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.

Preferential Radionuclide Release Due to Alpha Decay: Effects on Repository Performance

2004 ◽  
Vol 824 ◽  
Author(s):  
David A. Pickett ◽  
William M. Murphy
Keyword(s):  
Nuclear Waste ◽  
Spent Nuclear Fuel ◽  
Alpha Decay ◽  
Nuclear Regulatory Commission ◽  
Yucca Mountain ◽  
Total System ◽  
Secondary Phases ◽  
Regulatory Commission ◽  
Radionuclide Release ◽  
The U.S

AbstractWe model preferential release of 237Np, 234U, 230Th, 226Ra, and 210Pb from disposed commercial spent nuclear fuel as a result of alpha recoil damage, using the U.S. Nuclear Regulatory Commission (NRC) Total-system Performance Assessment (TPA) model for the potential repository at Yucca Mountain. Time-dependent augmentation of the ingrown component is simulated by increasing the initial parent inventory; we have used a factor of five increase, based on natural system observations. For 237Np, the magnitude of preferential release is subject to solubility limits. Stochastic TPA runs show a significant effect on modeled dose of preferential 237Np release, but low impact from the other four radionuclides. The mechanism could be ineffective if 237Np is incorporated into secondary phases. While our results are exploratory in nature, this approach to modeling decay-related enhancement of release can be applied in other nuclear waste disposal settings.

Yucca Mountain Project Status

2002 ◽  
Vol 757 ◽  
Author(s):  
Thomas E. Kiess ◽  
Stephen H. Hanauer
Keyword(s):  
Spent Nuclear Fuel ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Yucca Mountain ◽  
Department Of Energy ◽  
Geologic Repository ◽  
Regulatory Standard ◽  
Regulatory Commission ◽  
High Level ◽  
The U.S

ABSTRACTThe Yucca Mountain site was designated in July 2002 as the United States' location for a geological repository for spent nuclear fuel and other high-level radioactive wastes. This site designation was a watershed event in the history of the project, enabling the U.S. Department of Energy to seek a license from the U.S. Nuclear Regulatory Commission to construct and operate a geologic repository. Summarized below are the history and technical basis for this site designation and some key anticipated future events. Many of the significant events to date have been framed by the Nuclear Waste Policy Act (and Amendments) and the requirements of the regulatory standard.

Total System Performance Assessment Model for the Final Environmental Impact Statement for the Potential High-Level Nuclear Waste Repository at Yucca Mountain

2002 ◽  
Author(s):  
George J. Saulnier ◽  
K. Patrick Lee ◽  
Donald A. Kalinich ◽  
S. David Sevougian ◽  
Jerry A. McNeish
Keyword(s):  
System Performance ◽  
Transport Model ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Total System ◽  
Operating Modes ◽  
Final Rule ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Component Models

The total-system performance assessment (TSPA) model for the final environmental impact statement (FEIS) for the potential high-level nuclear-waste repository at Yucca Mountain, Nevada was developed from a series of analyses and model studies of the Yucca Mountain site. The U.S. Department of Energy (DOE) has recommended the Yucca Mountain, Nevada site for the potential development of a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. In May 2001, the DOE released the Yucca Mountain Science and Engineering Report (S&ER) for public review and comment. The S&ER summarizes more than 20 years of scientific and engineering studies supporting the site recommendation (SR). Following internal reviews of the S&ER and other documents, the DOE performed supplemental analyses of uncertainty in support of the SR as summarized in the Supplemental Science and Performance Analysis (SSPA) reports [2, 3]. The SSPA (1) provided insights into the impact of new scientific data and improved models and (2) evaluated a range of thermal operating modes and their effect on the predicted performance of a potential repository. The various updated component models for the SSPA resulted in a modified TSPA model, referred to as the supplemental TSPA model or SSPA TSPA model capturing the combined effects of the alternative model representations on system performance. The SSPA TSPA model was the basis for analyses for the FEIS for the Yucca Mountain site. However, after completion of the SSPA, the U.S. Environmental Protection Agency (EPA) released its final radiation-protection standards for the potential repository at Yucca Mountain (40 CFR Part 197). Compliance with the regulation required modification of several of the component models (e.g., the biosphere transport model and the saturated-zone transport model) in order to evaluate repository performance against the new standards. These changes were incorporated into the SSPA TSPA model. The resulting FEIS TSPA model, known as the “integrated TSPA model,” was used to perform the calculations presented in this report. The results of calculations using the FEIS TSPA model under a non-disruptive scenario, show that the potential disposal of commercial and DOE waste at a Yucca Mountain repository would not produce releases to the environment that would exceed the regulatory standards promulgated in the EPA Final Rule 10 CFR 197 and the NRC Final Rule 10 CFR 63 for both individual protection and groundwater protection. The analyses also show that both the high and low-temperature operating modes result in similar mean annual dose to the reasonably maximally exposed individual (RMEI). Further, the analyses show that consideration of intrusive and extrusive igneous events, human intrusion, or inclusion of the potential inventory of all radioactive material in the commercial and DOE inventory would not exceed those published standards.

Management of Mixed Hazardous and Radioactive Waste in the United States

2001 ◽  
Author(s):  
William Greenman ◽  
Kimberly Cole
Keyword(s):  
United States ◽  
Regulatory Authority ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Slow Development ◽  
Treatment Facilities ◽  
Mixed Waste ◽  
Treatment And Disposal ◽  
Regulatory Commission ◽  
The U.S

Abstract In the United States, mixed-waste is typically defined as waste that contains both radioactive constituents and non-radioactive constituents that pose a threat to human health or the environment (hazardous waste). Prior to 1986 the U.S. Nuclear Regulatory Commission (NRC) had sole regulatory authority over mixed-waste because of its radioactive constituents. In 1986, however, the U.S. Environmental Protections Agency (EPA) was granted regulatory authority over the hazardous constituents in mixed-waste; and, a system of dual regulation was created. Dual regulation of mixed-waste by the EPA and the NRC has caused significant problems for the regulated community. The burden of dual regulation has contributed to the slow development of treatment technologies, and to the overall lack of treatment capacity available to U.S generators of mixed-waste. This paper reviews the requirements that the EPA and the NRC mandate with regard to mixed-waste generation, treatment and disposal; and it explores technical impacts of those requirements as they relate to generators, treatment facilities and the public.

Estimates of Mean Consequences and Confidence Bounds on the Mean Associated With Low-Probability Seismic Events in Total System Performance Assessments

2007 ◽  
Author(s):  
Osvaldo Pensado ◽  
James Mancillas
Keyword(s):  
Performance Assessment ◽  
System Performance ◽  
Performance Assessments ◽  
Assessment Model ◽  
Nuclear Waste Repository ◽  
Seismic Events ◽  
Total System ◽  
Confidence Bounds ◽  
The Mean ◽  
Low Probability

An approach is described to estimate mean consequences and confidence bounds on the mean of seismic events with low probability of breaching components of the engineered barrier system. The approach is aimed at complementing total system performance assessment models used to understand consequences of scenarios leading to radionuclide releases in geologic nuclear waste repository systems. The objective is to develop an efficient approach to estimate mean consequences associated with seismic events of low probability, employing data from a performance assessment model with a modest number of Monte Carlo realizations. The derived equations and formulas were tested with results from a specific performance assessment model. The derived equations appear to be one method to estimate mean consequences without having to use a large number of realizations.

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