94 research outputs found
Basic Research Needs for Geosciences: Facilitating 21st Century Energy Systems
Executive Summary
Serious challenges must be faced in this century as the world seeks to meet global energy needs and at the same time reduce emissions of greenhouse gases to the atmosphere. Even with a growing energy supply from alternative sources, fossil carbon resources will remain in heavy use and will generate large volumes of carbon dioxide (CO2). To reduce the atmospheric impact of this fossil energy use, it is necessary to capture and sequester a substantial fraction of the produced CO2. Subsurface geologic formations offer a potential location for long-term storage of the requisite large volumes of CO2. Nuclear energy resources could also reduce use of carbon-based fuels and CO2 generation, especially if nuclear energy capacity is greatly increased. Nuclear power generation results in spent nuclear fuel and other radioactive materials that also must be sequestered underground. Hence, regardless of technology choices, there will be major increases in the demand to store materials underground in large quantities, for long times, and with increasing efficiency and safety margins.
Rock formations are composed of complex natural materials and were not designed by nature as storage vaults. If new energy technologies are to be developed in a timely fashion while ensuring public safety, fundamental improvements are needed in our understanding of how these rock formations will perform as storage systems.
This report describes the scientific challenges associated with geologic sequestration of large volumes of carbon dioxide for hundreds of years, and also addresses the geoscientific aspects of safely storing nuclear waste materials for thousands to hundreds of thousands of years. The fundamental crosscutting challenge is to understand the properties and processes associated with complex and heterogeneous subsurface mineral assemblages comprising porous rock formations, and the equally complex fluids that may reside within and flow through those formations. The relevant physical and chemical interactions occur on spatial scales that range from those of atoms, molecules, and mineral surfaces, up to tens of kilometers, and time scales that range from picoseconds to millennia and longer. To predict with confidence the transport and fate of either CO2 or the various components of stored nuclear materials, we need to learn to better describe fundamental atomic, molecular, and biological processes, and to translate those microscale descriptions into macroscopic properties of materials and fluids. We also need fundamental advances in the ability to simulate multiscale systems as they are perturbed during sequestration activities and for very long times afterward, and to monitor those systems in real time with increasing spatial and temporal resolution. The ultimate objective is to predict accurately the performance of the subsurface fluid-rock storage systems, and to verify enough of the predicted performance with direct observations to build confidence that the systems will meet their design targets as well as environmental protection goals.
The report summarizes the results and conclusions of a Workshop on Basic Research Needs for Geosciences held in February 2007. Five panels met, resulting in four Panel Reports, three Grand Challenges, six Priority Research Directions, and three Crosscutting Research Issues. The Grand Challenges differ from the Priority Research Directions in that the former describe broader, long-term objectives while the latter are more focused
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Geological problems in radioactive waste isolation - second worldwide review
The first world wide review of the geological problems in radioactive waste isolation was published by Lawrence Berkeley National Laboratory in 1991. This review was a compilation of reports that had been submitted to a workshop held in conjunction with the 28th International Geological Congress that took place July 9-19, 1989 in Washington, D.C. Reports from 15 countries were presented at the workshop and four countries provided reports after the workshop, so that material from 19 different countries was included in the first review. It was apparent from the widespread interest in this first review that the problem of providing a permanent and reliable method of isolating radioactive waste from the biosphere is a topic of great concern among the more advanced, as well as the developing, nations of the world. This is especially the case in connection with high-level waste (HLW) after its removal from nuclear power plants. The general concensus is that an adequate isolation can be accomplished by selecting an appropriate geologic setting and carefully designing the underground system with its engineered barriers. This document contains the Second Worldwide Review of Geological Problems in Radioactive Waste Isolation, dated September 1996
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Characterizing Vs profiles by the SASW method and comparison with other seismic methods
textThe shear wave velocity (VS) profile has been used as an important parameter in
characterizing geotechnical sites and performing earthquake designs. The SpectralAnalysis-of-Surface-Wave
(SASW) method, one of the VS profiling methods, was
developed in the early 1980s. This method is a non-intrusive test which uses Rayleigh
waves, one kind of surface wave, to explore the subsurface. The SASW method has
been widely used in geotechnical earthquake engineering to profile soil and rock sites.
All equipment required to conduct the SASW test is deployed on the ground surface and
no boreholes are needed.
In this study, the SASW method was used to measure shear wave velocity profiles
in four different geographic regions. These four regions are: (1) Imperial Valley, CA, (2)
Taiwan, (3) Hanford, WA and (4) Yucca Mountain, NV. The SASW tests performed at
these locations were for different purposes. At the Imperial Valley and Taiwan sites, the
SASW tests were carried out at the locations of strong motion recorders (SMR) to obtain
VS profiles of the top 30 m (VS,30). At the Hanford and Yucca Mountain sites, deeper
profiling (>300 m) was required to obtain VS values of the geotechnical structure around
or beneath critical facilities associated with the handling, treatment and/or storage of
high-level radioactive waste.
The VS,30 values determined by the SASW method were used to classify the test
sites based on the International Building Code (IBC-2006) provisions. Available
downhole and suspension logging measurements at/near the SASW test sites were also
used to determine VS,30. In addition, deeper VS profiles determined by the SASW,
downhole and suspension logging methods were compared. By doing so, the
consistency between the three seismic surveys methods and the reliability of the SASW
method were studied. Finally, sensitivity studies of the SASW method were conducted
to investigate: (1) the impact on the final VS profile of changing assumed parameters in
the SASW data reduction process, and (2) the capability of the SASW method to detect
relatively soft layers sandwiched between stiffer layers.Civil, Architectural, and Environmental Engineerin
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Site characterization plan: Yucca Mountain site, Nevada research and development area, Nevada: Consultation draft, Nuclear Waste Policy Act
Chapter six describes the basis for facility design, the completed facility conceptual design, the completed analytical work relating to the resolution of design issues, and future design-related work. The basis for design and the conceptual design information presented in this chapter meet the requirements of the Nuclear Waste Policy Act of 1982, for a conceptual repository design that takes into account site-specific requirements. This information is presented to permit a critical evaluation of planned site characterization activities. Chapter seven describes waste package components, emplacement environment, design, and status of research and development that support the Nevada Nuclear Waste Storage Investigation (NNWSI) Project. The site characterization plan (SCP) discussion of waste package components is contained entirely within this chapter. The discussion of emplacement environment in this chapter is limited to considerations of the environment that influence, or which may influence, if perturbed, the waste packages and their performance (particularly hydrogeology, geochemistry, and borehole stability). The basis for conceptual waste package design as well as a description of the design is included in this chapter. The complete design will be reported in the advanced conceptual design (ACD) report and is not duplicated in the SCP. 367 refs., 173 figs., 68 tabs
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