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Title: CHARACTERIZING THE YUCCA MOUNTAIN SITE FOR DEVELOPING SEISMIC DESIGN GROUND MOTIONS

Abstract

Yucca Mountain, Nevada is the designated site for the first long-term geologic repository to safely dispose spent nuclear fuel and high-level nuclear waste in the U.S. Yucca Mountain consists of stacked layers of welded and non-welded volcanic tuffs. Site characterization studies are being performed to assess its future performance as a permanent geologic repository. These studies include the characterization of the shear-wave velocity (Vs) structure of the repository block and the surface facilities area. The Vs data are an input in the calculations of ground motions for the preclosure seismic design and for postclosure performance assessment and therefore their accurate estimation is needed. Three techniques have been employed: 24 downhole surveys, 15 suspension seismic logging surveys and 95 spectral-analysis-of-surface-waves (SASW) surveys have been performed to date at the site. The three data sets were compared with one another and with Vs profiles developed from vertical seismic profiling data collected by the Lawrence Berkeley National Laboratory and with Vs profiles developed independently by the University of Nevada, Reno using the refraction microtremor technique. Based on these data, base case Vs profiles have been developed and used in site response analyses. Since the question of adequate sampling arises in site characterization programsmore » and a correlation between geology and Vs would help address this issue, a possible correlation was evaluated. To assess the influence of different factors on velocity, statistical analyses of the Vs data were performed using the method of multi-factor Analysis of Variance (ANOVA). The results of this analysis suggest that the effect of each of three factors, depth, lithologic unit, and spatial location, on velocity is statistically significant. Furthermore, velocity variation with depth is different at different spatial locations: Preliminary results show that the lithologic unit alone explains about 54% and 42% of the velocity variation in the suspension and downhole data sets, respectively. The three factors together explain about 73% and 81% of the velocity variation in the suspension and downhole data sets, respectively. Development of a relationship, using multiple regression analysis, which may be used as a predictive tool to estimate velocity at a new location, is currently being examined.« less

Authors:
Publication Date:
Research Org.:
Yucca Mountain Project, Las Vegas, Nevada
Sponsoring Org.:
USDOE
OSTI Identifier:
883063
DOE Contract Number:
DE-AC08-91RW00134
Resource Type:
Conference
Resource Relation:
Conference: 2006 SSA Centennial Annual Meeting
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; DESIGN; GEOLOGY; GROUND MOTION; NUCLEAR FUELS; PERFORMANCE; RADIOACTIVE WASTES; REFRACTION; REGRESSION ANALYSIS; SAMPLING; SITE CHARACTERIZATION; VELOCITY; YUCCA MOUNTAIN; SPENT FUELS

Citation Formats

S. Upadhyaya, I. Wong, R. Kulkarni, K. Stokoe, M. Dober, W. Silva, and R. Quittmeyer. CHARACTERIZING THE YUCCA MOUNTAIN SITE FOR DEVELOPING SEISMIC DESIGN GROUND MOTIONS. United States: N. p., 2006. Web.
S. Upadhyaya, I. Wong, R. Kulkarni, K. Stokoe, M. Dober, W. Silva, and R. Quittmeyer. CHARACTERIZING THE YUCCA MOUNTAIN SITE FOR DEVELOPING SEISMIC DESIGN GROUND MOTIONS. United States.
S. Upadhyaya, I. Wong, R. Kulkarni, K. Stokoe, M. Dober, W. Silva, and R. Quittmeyer. Fri . "CHARACTERIZING THE YUCCA MOUNTAIN SITE FOR DEVELOPING SEISMIC DESIGN GROUND MOTIONS". United States. doi:. https://www.osti.gov/servlets/purl/883063.
@article{osti_883063,
title = {CHARACTERIZING THE YUCCA MOUNTAIN SITE FOR DEVELOPING SEISMIC DESIGN GROUND MOTIONS},
author = {S. Upadhyaya, I. Wong, R. Kulkarni, K. Stokoe, M. Dober, W. Silva, and R. Quittmeyer},
abstractNote = {Yucca Mountain, Nevada is the designated site for the first long-term geologic repository to safely dispose spent nuclear fuel and high-level nuclear waste in the U.S. Yucca Mountain consists of stacked layers of welded and non-welded volcanic tuffs. Site characterization studies are being performed to assess its future performance as a permanent geologic repository. These studies include the characterization of the shear-wave velocity (Vs) structure of the repository block and the surface facilities area. The Vs data are an input in the calculations of ground motions for the preclosure seismic design and for postclosure performance assessment and therefore their accurate estimation is needed. Three techniques have been employed: 24 downhole surveys, 15 suspension seismic logging surveys and 95 spectral-analysis-of-surface-waves (SASW) surveys have been performed to date at the site. The three data sets were compared with one another and with Vs profiles developed from vertical seismic profiling data collected by the Lawrence Berkeley National Laboratory and with Vs profiles developed independently by the University of Nevada, Reno using the refraction microtremor technique. Based on these data, base case Vs profiles have been developed and used in site response analyses. Since the question of adequate sampling arises in site characterization programs and a correlation between geology and Vs would help address this issue, a possible correlation was evaluated. To assess the influence of different factors on velocity, statistical analyses of the Vs data were performed using the method of multi-factor Analysis of Variance (ANOVA). The results of this analysis suggest that the effect of each of three factors, depth, lithologic unit, and spatial location, on velocity is statistically significant. Furthermore, velocity variation with depth is different at different spatial locations: Preliminary results show that the lithologic unit alone explains about 54% and 42% of the velocity variation in the suspension and downhole data sets, respectively. The three factors together explain about 73% and 81% of the velocity variation in the suspension and downhole data sets, respectively. Development of a relationship, using multiple regression analysis, which may be used as a predictive tool to estimate velocity at a new location, is currently being examined.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Feb 24 00:00:00 EST 2006},
month = {Fri Feb 24 00:00:00 EST 2006}
}

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  • A methodology and preliminary application for designing repository openings to withstand vibratory ground motions is presented. The methodology first establishes the design basis ground motion based on the usage category, performance goals, and hazard exceedance guidelines and incorporates those motions into the more general drift design methodology. The repository drift design methodology includes the effects of the in situ stresses and the thermal loads generated from the heat released from the nuclear waste packages. Empirical and analytical methods for design for seismic loading are reviewed, and it is concluded that analytical methods provide the only means method to adequately incorporatemore » the effects of seismic and thermal loads on design. Quasi-static and dynamic analysis methods are discussed. The example application to the potential repository at the Yucca Mountain site illustrates, by using the quasi-static method, that the seismic loads in combination with the thermal loads can be significant in the design of the ground support/reinforcement system in some locations. Under present expected conditions, the seismic loads themselves are not excessive and can be accommodated in the design by available ground support/reinforcement systems. However, in the waste emplacement drift where the thermal loads are high, the potential and additional seismic loads could require novel ground support/reinforcement designs and maintenance.« less
  • The Department of Energy has proposed a methodology for developing a ground-motion design basis for prospective facilities at Yucca Mountain that are important to safety. The methodology utilizes a quasi-deterministic construct that is designed to provide a conservative, robust, and reproducible estimate of ground motion that has a one-in-ten chance of occurring during the preclosure period. This estimate is intended to define a ground-motion level for which the seismic design would ensure minimal disruption to operations; engineering analyses to ensure safe performance in the unlikely event that the design basis is exceeded are a part of the proposed methodology. 8more » refs.« less
  • This paper discusses a methodology for developing a ground-motion design basis for prospective facilities at Yucca Mountain that are important to safety. The methodology utilizes a quasi-deterministic construct called the 10,000-year cumulative-slip earthquake that is designed to provide a conservative, robust, and reproducible estimate of ground motion that has a one-in-ten chance of occurring during the preclosure period. This estimate is intended to define a ground-motion level for which the seismic design would ensure minimal disruption to operations engineering analyses to ensure safe performance are included.
  • Yucca Mountain, the potential site of a repository for high-level radioactive waste, is situated in a region of natural and man-made seismicity. Underground openings excavated at this site must be designed for worker safety in the seismic environment anticipated for the preclosure period. This includes accesses developed for site characterization regardless of the ultimate outcome of the repository siting process. Experience with both civil and mining structures has shown that underground openings are much more resistant to seismic effects than surface structures, and that even severe dynamic strains can usually be accommodated with proper design. This paper discusses the designmore » and performance of lined openings in the seismic environment of the potential site. The types and ranges of possible ground motions (seismic loads) are briefly discussed. Relevant historical records of underground opening performance during seismic loading are reviewed. Simple analytical methods of predicting liner performance under combined in situ, thermal, and seismic loading are presented, and results of calculations are discussed in the context of realistic performance requirements for concrete-lined openings for the preclosure period. Design features that will enhance liner stability and mitigate the impact of the potential seismic load are reviewed. The paper is limited to preclosure performance concerns involving worker safety because present decommissioning plans specify maintaining the option for liner removal at seal locations, thus decoupling liner design from repository postclosure performance issues.« less
  • Yucca Mountain, the potential site of a repository for high-level radioactive waste, is situated in a region of natural and man-made seismicity. Underground openings excavated at this site must be designed for worker safety in the seismic environment anticipated for the preclosure period. This includes accesses developed for site characterization regardless of the ultimate outcome of the repository siting process. Experience with both civil and mining structures has shown that underground openings are much more resistant to seismic effects than surface structures, and that even severe dynamic strains can usually be accommodated with proper design. This paper discusses the designmore » and performance of lined openings in the seismic environment of the potential site. The types and ranges of possible ground motions (seismic loads) are briefly discussed. Relevant historical records of underground opening performance during seismic loading are reviewed. Simple analytical methods of predicting liner performance under combined in situ, thermal, and seismic loading are presented, and results of calculations are discussed in the context of realistic performance requirements for concrete-lined openings for the preclosure period. Design features that will enhance liner stability and mitigate the impact of the potential seismic load are reviewed. The paper is limited to preclosure performance concerns involving worker safety because present decommissioning plans specify maintaining the option for liner removal at seal locations, thus decoupling liner design from repository postclosure performance issues.« less