1,892 research outputs found
Performance implications of waste package emplacement orientation
Emplacement borehole orientation directly impacts many aspects of the Engineered Barrier System (EBS) and interactions with the near field environment. This paper considers the impacts of orientation on the hydrologic portion of the environment and its interactions with the EBS. The hydrologic environment is considered from a conceptual standpoint, the numerical analyses are left for subsequent work. As reported in this paper, several aspects of the hydrological environment are more favorable for long term performance of vertically oriented rather than horizontally oriented Waste Packages. 19 refs., 15 figs
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Inelastic deformations of fault and shear zones in granitic rock
Deformations during heating and cooling of three drifts in granitic rock were influenced by the presence of faults and shear zones. Thermal deformations were significantly larger in sheared and faulted zones than where the rock was jointed, but neither sheared nor faulted. Furthermore, thermal deformations in faulted or sheared rock were not significantly recovered during subsequent cooling, thus a permanent deformation remained. This inelastic response is in contrast with elastic behavior identified in unfaulted and unsheared rock segments. A companion paper indicates that deformations in unsheared or unfaulted rock were effectively modeled as an elastic response. We conclude that permanent deformations occurred in fractures with crushed minerals and fracture filling or gouge materials. Potential mechanisms for this permanent deformation are asperity readjustments during thermal deformations, micro-shearing, asperity crushing and crushing of the secondary fracture filling minerals. Additionally, modulus differences in sheared or faulted rock as compared to more intact rock would result in greater deformations in response to the same thermal loads
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Near field and altered zone environmental report Volume I: technical bases for EBS design
This report presents an updated summary of results for the waste package (WP) and engineered barrier system (EBS) evaluations, including materials testing, waste-form characterization, EBS performance assessments, and near-field environment (NFE) characterization. Materials testing, design criteria and concept development, and waste-form characterization all require an understanding of the environmental conditions that will interact with the WP and EBS. The Near-Field Environment Report (NFER) was identified in the Waste Package Plan (WPP) (Harrison- Giesler, 1991) as the formal means for transmitting and documenting this information
Convective Fingering of an Autocatalytic Reaction Front
We report experimental observations of the convection-driven fingering
instability of an iodate-arsenous acid chemical reaction front. The front
propagated upward in a vertical slab; the thickness of the slab was varied to
control the degree of instability. We observed the onset and subsequent
nonlinear evolution of the fingers, which were made visible by a {\it p}H
indicator. We measured the spacing of the fingers during their initial stages
and compared this to the wavelength of the fastest growing linear mode
predicted by the stability analysis of Huang {\it et. al.} [{\it Phys. Rev. E},
{\bf 48}, 4378 (1993), and unpublished]. We find agreement with the thickness
dependence predicted by the theory.Comment: 11 pages, RevTex with 3 eps figures. To be published in Phys Rev E,
[email protected], [email protected], [email protected]
A tetraethylene glycol coat gives gold nanoparticles long in vivo half-lives with minimal increase in size
In this study, we describe the experiments determining whether coating gold nanoparticles with tetraethylene glycol (TEG) provides pharmacologically relevant advantages, such as increased serum half-life and resistance to protein adsorption. Monodisperse TEG-coated, NaBH4-reduced gold nanoparticles with a hydrodynamic size comparable to albumin were synthesized by reducing gold chloride with NaBH4 under alkaline conditions in the presence of TEG-SH. The particles were characterized by gel electrophoresis, column chromatography, and transmission electron microscopy. The nanoparticles were subsequently injected intravenously into mice, and their half-lives and final destinations were determined via photometric analysis, light microscopy (LM), and transmission electron microscopy. The TEG particles had a long half-life (~400 minutes) that was not influenced by splenectomy. After 500 minutes of injection, TEG particles were found in kidney proximal tubule cell vesicles and in spleen red and white pulp. The particles induced apoptosis in the spleen red pulp but not in white pulp or the kidney. Some of the TEG particles appeared to have undergone ligand exchange reactions that increased their charge. The TEG particles were shown to be resistant to nonspecific protein adsorption, as judged by gel electrophoresis and column chromatography. These results demonstrate that naturally monodisperse, small-sized gold nanoparticles coated with TEG have long in vivo plasma half-lives, are minimally toxic, and are resistant to protein adsorption. This suggests that a TEG coating should be considered as an alternative to a polyethylene glycol coating, which is polydisperse and of much larger size
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A progress report for the large block test of the coupled thermal-mechanical-hydrological-chemical processes
This is a progress report on the Large Block Test (LBT) project. The purpose of the LBT is to study some of the coupled thermal-mechanical-hydrological-chemical (TMHC) processes in the near field of a nuclear waste repository under controlled boundary conditions. To do so, a large block of Topopah Spring tuff will be heated from within for about 4 to 6 months, then cooled down for about the same duration. Instruments to measure temperature, moisture content, stress, displacement, and chemical changes will be installed in three directions in the block. Meanwhile, laboratory tests will be conducted on small blocks to investigate individual thermal-mechanical, thermal-hydrological, and thermal-chemical processes. The fractures in the large block will be characterized from five exposed surfaces. The minerals on fracture surfaces will be studied before and after the test. The results from the LBT will be useful for testing and building confidence in models that will be used to predict TMHC processes in a repository. The boundary conditions to be controlled on the block include zero moisture flux and zero heat flux on the sides, constant temperature on the top, and constant stress on the outside surfaces of the block. To control these boundary conditions, a load-retaining frame is required. A 3 x 3 x 4.5 m block of Topopah Spring tuff has been isolated on the outcrop at Fran Ridge, Nevada Test Site. Pre-test model calculations indicate that a permeability of at least 10{sup -15} m{sup 2} is required so that a dryout zone can be created within a practical time frame when the block is heated from within. Neutron logging was conducted in some of the vertical holes to estimate the initial moisture content of the block. It was found that about 60 to 80% of the pore volume of the block is saturated with water. Cores from the vertical holes have been used to map the fractures and to determine the properties of the rock. A current schedule is included in the report
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Large block test status report
This report is intended to serve as a status report, which essentially transmits the data that have been collected to date on the Large Block Test (LBT). The analyses of data will be performed during FY98, and then a complete report will be prepared. This status report includes introductory material that is not needed merely to transmit data but is available at this time and therefore included. As such, this status report will serve as the template for the future report, and the information is thus preserved
Aerodynamic flight evaluation analysis and data base update
Research was conducted to determine the feasibility of replacing the Solid Rocket Boosters on the existing Space Shuttle Launch Vehicle (SSLV) with Liquid Rocket Boosters (LRB). As a part of the LRB selection process, a series of wind tunnel tests were conducted along with aero studies to determine the effects of different LRB configurations on the SSLV. Final results were tabulated into increments and added to the existing SSLV data base. The research conducted in this study was taken from a series of wind tunnel tests conducted at Marshall's 14-inch Trisonic Wind Tunnel. The effects on the axial force (CAF), normal force (CNF), pitching moment (CMF), side force (CY), wing shear force (CSR), wing torque moment (CTR), and wing bending moment (CBR) coefficients were investigated for a number of candidate LRB configurations. The aero effects due to LRB protuberances, ET/LRB separation distance, and aft skirts were also gathered from the tests. Analysis was also conducted to investigate the base pressure and plume effects due to the new booster geometries. The test results found in Phases 1 and 2 of wind tunnel testing are discussed and compared. Preliminary LRB lateral/directional data results and trends are given. The protuberance and gap/skirt effects are discussed. The base pressure/plume effects study is discussed and results are given
Spent Fuel Test-Climax: core logging for site investigation and instrumentation
As an integral part of the Spent Fuel Test-Climax 5150 ft (1570 m) of granite core was obtained. This core was diamond drilled in various sizes, mainly 38-mm and 76-mm diameters. The core was teken with single tube core barrels and was unoriented. Techniques used to drill and log this core are discussed, as well as techniques to orient the core. Of the 5150 ft (1570 m) of core more than 3645 ft (1111 m) was retained and logged in some detail. As a result of the core logging, geologic discontinuities were identified, joint frequency and spacing characterized. Discontinuities identified included several joint sets, shear zones and faults. Correlations based on coring along were generally found to be impossible, even for the more prominent features. The only feature properly correlated from the exploratory drilling was the fault system at the end of the facility, but it was not identified from the exploratory core as a fault. Identification of discontinuities was later helped by underground mapping that identified several different joint sets with different characteristics. It was found that joint frequency varied from 0.3 to 1.1 joint per foot of core for open fractures and from 0.3 to 3.3/ft for closed or healed fractures. Histograms of fracture spacing indicate that there is likely a random distribution of spacing superimposed upon uniformly spaced fractures. It was found that a low angle joint set had a persistent mean orientation. These joints were healed and had pervasive wall rock alteration which made identification of joints in this set possible. The recognition of a joint set with known attitude allowed orientation of much of the core. This orientation technique was found to be effective. 10 references, 25 figures, 4 tables
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