Activation Measurements for Thermal Neutrons, U.S. Measurements of 36Cl in Mineral Samples from Hiroshima and Nagasaki; and Measurement of 63 Ni in Copper Samples From Hiroshima by Accelerator Mass Spectrometry (open access)

Activation Measurements for Thermal Neutrons, U.S. Measurements of 36Cl in Mineral Samples from Hiroshima and Nagasaki; and Measurement of 63 Ni in Copper Samples From Hiroshima by Accelerator Mass Spectrometry

The present paper presents the {sup 36}Cl measurement effort in the US. A large number of {sup 36}Cl measurements have been made in both granite and concrete samples obtained from various locations and distances in Hiroshima and Nagasaki. These measurements employed accelerator mass spectrometry (AMS) to quantify the number of atoms of {sup 36}Cl per atom of total Cl in the sample. Results from these measurements are presented here and discussed in the context of the DS02 dosimetry reevaluation effort for Hiroshima and Nagasaki atomic-bomb survivors. The production of {sup 36}Cl by bomb neutrons in mineral samples from Hiroshima and Nagasaki was primarily via the reaction {sup 35}Cl(n,{gamma}){sup 36}Cl. This reaction has a substantial thermal neutron cross-section (43.6 b at 0.025 eV) and the product has a long half-life (301,000 y). hence, it is well suited for neutron-activation detection in Hiroshima and Nagasaki using AMS more than 50 years after the bombings. A less important reaction for bomb neutrons, {sup 39}K(n,{alpha}){sup 36}Cl, typically produces less than 10% of the {sup 36}Cl in mineral samples such as granite and concrete, which contain {approx} 2% potassium. In 1988, only a year after the publication of the DS86 final report (Roesch 1987), it …
Date: January 14, 2005
Creator: Straume, Tore; Marchetti, Alfredo A.; Egbert, Stephen D.; Roberts, James A.; Men, Ping; Fujita, Shoichiro et al.
Object Type: Report
System: The UNT Digital Library
Attempts to Produce D2-Gas-Filled Be Shells (open access)

Attempts to Produce D2-Gas-Filled Be Shells

We have attempted to fabricate some 0.5 mm diameter D{sub 2}-gas-filled Be shells by coating gas-filled PVA-coated GDP mandrels with Cu-doped Be. We find that during the coating all (or most) of the gas leaks out. This is likely due to either small cracks or holes in the coating that are formed at the earliest points and are maintained during the thickness build-up of the coating, and/or to some level of intrinsic porosity in the coating. This memo documents our efforts.
Date: January 14, 2005
Creator: Cook, Bob; McElfresh, Mike; Alford, Craig; Fought, Eric & Letts, Steve
Object Type: Report
System: The UNT Digital Library
Development of a Certified Low-Level Waste Stream from Analytical Laboratory Operations at Lawrence Livermore National Laboratory (open access)

Development of a Certified Low-Level Waste Stream from Analytical Laboratory Operations at Lawrence Livermore National Laboratory

Chemistry and Materials Science Environmental Services (CES) is LLNL's on-site environmental analytical laboratory, analyzing approximately 2500 samples annually generally for waste characterization purposes. Due to the lack of process knowledge for analyzed samples, the waste produced by CES has traditionally been characterized on a ''worst-case'' basis as RCRA-hazardous mixed waste. By instituting rigorous ''up-front'' waste characterization, including segregation of acutely/extremely hazardous materials, utilizing regulatory exemptions, and developing a novel radiological characterization strategy, CES was able to receive approval for a certified LLW waste stream, adequately characterized for disposal at the Nevada Test Site. In the 10 months of operating history, CES has diverted 33% of its waste (by mass) from mixed to LLW. This will result in significant cost savings and reduction in waste re-handling/personnel exposure.
Date: January 14, 2005
Creator: Gaylord, R. F.; Drake, J. A. & Gallagher, P. J.
Object Type: Article
System: The UNT Digital Library
Development of Biocatalyst for the Fermentation of Agricultural Feedstocks to Chemicals (open access)

Development of Biocatalyst for the Fermentation of Agricultural Feedstocks to Chemicals

Yeasts were engineered to increase rates for fermentation of xylose (a common biomass derived sugar) to lactic acid or ethanol.
Date: January 14, 2005
Creator: Suominen, Pirkko; Glassner, David & Kean, Robert
Object Type: Report
System: The UNT Digital Library
Dose-Rate Dependence of High-Dose Health Effects in Humans from Photon Radiation with Application to Radiological Terrorism (open access)

Dose-Rate Dependence of High-Dose Health Effects in Humans from Photon Radiation with Application to Radiological Terrorism

In 1981, as part of a symposium entitled ''The Control of Exposure of the Public to Ionizing Radiation in the Event of Accident or Attack,'' Lushbaugh, H?bner, and Fry published a paper examining ''radiation tolerance'' of various human health endpoints as a function of dose rate. This paper may not have received the notice it warrants. The health endpoints examined by Lushbaugh et al. were the lethal dose that will kill 50% of people within 60 days of exposure without medical care (LD50/60); severe bone marrow damage in healthy men; severe bone marrow damage in leukemia patients; temporary sterility (azoospermia); reduced male fertility; and late effects such as cancer. Their analysis was grounded in extensive clinical experience and anchored to a few selected data points, and based on the 1968 dose-rate dependence theory of J.L. Bateman. The Lushbaugh et al. paper did not give predictive equations for the relationships, although they were implied in the text, and the relationships were presented in a non-intuitive way. This work derives the parameters needed in Bateman's equation for each health endpoint, tabulates the results, and plots them in a more conventional manner on logarithmic scales. The results give a quantitative indication of how …
Date: January 14, 2005
Creator: Strom, Daniel J.
Object Type: Report
System: The UNT Digital Library
HETEROGENEOUS REBURNING BY MIXED FUELS (open access)

HETEROGENEOUS REBURNING BY MIXED FUELS

Recent studies of heterogeneous reburning, i.e., reburning involving a coal-derived char, have elucidated its variables, kinetics and mechanisms that are valuable to the development of a highly efficient reburning process. Young lignite chars contain catalysts that not only reduce NO, but they also reduce HCN that is an important intermediate that recycles to NO in the burnout zone. Gaseous CO scavenges the surface oxides that are formed during NO reduction, regenerating the active sites on the char surface. Based on this mechanistic information, cost-effective mixed fuels containing these multiple features has been designed and tested in a simulated reburning apparatus. Remarkably high reduction of NO and HCN has been observed and it is anticipated that mixed fuel will remove 85% of NO in a three-stage reburning process.
Date: January 14, 2005
Creator: Chen, Wei-Yin & Gathitu, Benson B.
Object Type: Report
System: The UNT Digital Library
Modeling biogechemical reactive transport in a fracture zone (open access)

Modeling biogechemical reactive transport in a fracture zone

A coupled model of groundwater flow, reactive solute transport and microbial processes for a fracture zone of the Aspo site at Sweden is presented. This is the model of the so-called Redox Zone Experiment aimed at evaluating the effects of tunnel construction on the geochemical conditions prevailing in a fracture granite. It is found that a model accounting for microbially-mediated geochemical processes is able to reproduce the unexpected measured increasing trends of dissolved sulfate and bicarbonate. The model is also useful for testing hypotheses regarding the role of microbial processes and evaluating the sensitivity of model results to changes in biochemical parameters.
Date: January 14, 2005
Creator: Molinero, Jorge; Samper, Javier; Yang, Chan Bing, and Zhang, Guoxiang & Guoxiang, Zhang
Object Type: Article
System: The UNT Digital Library
NOVEL PREPARATION AND MAGNETO CHEMICAL CHARACTERIZATION OF NANO-PARTICLE MIXED ALCOHOL CATALYSTS (open access)

NOVEL PREPARATION AND MAGNETO CHEMICAL CHARACTERIZATION OF NANO-PARTICLE MIXED ALCOHOL CATALYSTS

We have developed effective nanoparticle incorporated heterogeneous F-T catalysts starting with the synthesis of Fe, Co, Cu nanoparticles using Fe(acac){sub 3}, Co(acac){sub 2}, and Cu(acac){sub 2} precursors and incorporating the nanoparticles into alumina sol-gel to yield higher alkanes production. SEM/EDX, XRD, BET, VSM and SQUID experimental techniques were used to characterize the catalysts, and GC/MS were used for catalytic product analysis. The nanoparticle oxide method gave the highest metal loading. In case of mixed metals it seems that Co or Cu interferes and reduces Fe metal loading. The XRD pattern for nanoparticle mixed metal oxides show alloy formation between cobalt and iron, and between copper and iron in sol-gel prepared alumina granules. The alloy formation is also supported by DTA and VMS data. The magnetization studies were used to estimate the catalyst activity in pre- and post-catalysts. A lower limit of {approx}40% for the reduction efficiency was obtained due to hydrogenation at 450 C for 4 hrs. About 85% of the catalyst has become inactive after 25 hrs of catalytic reaction, probably by forming carbides of Fe and Co. The low temperature (300 K to 4.2 K) SQUID magnetometer results indicate a superparamagnetic character of metal nanoparticles with a wide …
Date: January 14, 2005
Creator: Naidu, Seetala V. & Siriwardane, Upali
Object Type: Report
System: The UNT Digital Library
PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP (VOLUME 70) (open access)

PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP (VOLUME 70)

The Relativistic Heavy Ion Collider (RHIC) was commissioned for heavy ion collisions and for polarized pp collisions in 2001. All principal components of the accelerator chain were operational by the 2003 RHIC run. Approximately 50 papers on RHIC experimental results have been published in refereed journals to date. This is a testament to the vast amount of exciting new information and the unprecedented analysis and publication rate from RHIC. A number of signals of creation of matter at extreme energy density, and of new physics in that matter, have been observed. The RHIC community has been heavily engaged in discussion about these signals, and about the appropriate level of proof for Quark Gluon Plasma discovery at the RHIC. In fact, such discussions were the subject of an earlier RBRC Workshop. One of the striking results from heavy ion collisions at RHIC is that the quark gluon plasma accessible appears to be strongly coupled. The properties of strongly coupled plasmas are of intense interest in the traditional Plasma Physics community, who have been developing tools to study such matter theoretically and experimentally. Despite the fact that one plasma interacts electromagnetically and the other through the strong interaction, there is tremendous commonality …
Date: January 14, 2005
Creator: JACAK, B.; SHURYAK, E.; HALLMAN, T.; BASS, S. & DAVIDSON, R.
Object Type: Article
System: The UNT Digital Library
Radiation Diffusion: An Overview of Physical and Numerical Concepts (open access)

Radiation Diffusion: An Overview of Physical and Numerical Concepts

An overview of the physical and mathematical foundations of radiation transport is given. Emphasis is placed on how the diffusion approximation and its transport corrections arise. An overview of the numerical handling of radiation diffusion coupled to matter is also given. Discussions center on partial temperature and grey methods with comments concerning fully implicit methods. In addition finite difference, finite element and Pert representations of the div-grad operator is also discussed
Date: January 14, 2005
Creator: Graziani, F R
Object Type: Article
System: The UNT Digital Library
Shock Initiation of Energetic Materials at Different Initial Temperatures (open access)

Shock Initiation of Energetic Materials at Different Initial Temperatures

Shock initiation is one of the most important properties of energetic materials, which must transition to detonation exactly as intended when intentionally shocked and not detonate when accidentally shocked. The development of manganin pressure gauges that are placed inside the explosive charge and record the buildup of pressure upon shock impact has greatly increased the knowledge of these reactive flows. This experimental data, together with similar data from electromagnetic particle velocity gauges, has allowed us to formulate the Ignition and Growth model of shock initiation and detonation in hydrodynamic computer codes for predictions of shock initiation scenarios that cannot be tested experimentally. An important problem in shock initiation of solid explosives is the change in sensitivity that occurs upon heating (or cooling). Experimental manganin pressure gauge records and the corresponding Ignition and Growth model calculations are presented for two solid explosives, LX-17 (92.5 % triaminotrinitrobenzene (TATB) with 7.5 % Kel-F binder) and LX-04 (85 % octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine (HMX) with 15 % Viton binder) at several initial temperatures.
Date: January 14, 2005
Creator: Urtiew, P A & Tarver, C M
Object Type: Article
System: The UNT Digital Library
Spatially Continuous Mixed Simplified P2-P1 Solutions for Multidimensional Geometries (open access)

Spatially Continuous Mixed Simplified P2-P1 Solutions for Multidimensional Geometries

The simplified P{sub N} (SP{sub N}) angular approximation to the neutron transport equation has received renewed interest in recent years [1-3]. The even-order simplified P{sub 2} angular approximation has been shown to yield improved accuracy over the P{sub 1} (diffusion) angular approximation for problems in which the P{sub 1} approximation is reasonably accurate [1]. In particular, integral quantities such as reaction rates and eigenvalues computed by the SP{sub 2} approximation are typically more accurate. The SP{sub 2} scalar flux spatial distributions are also often more accurate than the P{sub 1} distributions away from material interfaces and source discontinuities. However, the SP{sub 2} scalar flux distributions are spatially discontinuous at material interfaces and source discontinuities. These spatial discontinuities are unphysical, aesthetically displeasing, and can lead to large inaccuracies near interfaces. Brantley [4] has recently investigated combining the P{sub 1} and P{sub 2} angular approximations in planar geometry to eliminate the discontinuities in the P{sub 2} scalar flux distributions near material interfaces and source discontinuities. In essence, the P{sub 1} angular approximation is used at material interfaces and source discontinuities to obtain spatially continuous scalar flux distributions; the P{sub 2} angular approximation is utilized elsewhere to take advantage of its improved accuracy. …
Date: January 14, 2005
Creator: Brantley, P S & Tomasevic, D I
Object Type: Article
System: The UNT Digital Library
Technical Analysis of Hydrogen Production (open access)

Technical Analysis of Hydrogen Production

The aim of this work was to assess issues of cost, and performance associated with the production and storage of hydrogen via following three feedstocks: sub-quality natural gas (SQNG), ammonia (NH{sub 3}), and water. Three technology areas were considered: (1) Hydrogen production utilizing SQNG resources, (2) Hydrogen storage in ammonia and amine-borane complexes for fuel cell applications, and (3) Hydrogen from solar thermochemical cycles for splitting water. This report summarizes our findings with the following objectives: Technoeconomic analysis of the feasibility of the technology areas 1-3; Evaluation of the hydrogen production cost by technology areas 1; and Feasibility of ammonia and/or amine-borane complexes (technology areas 2) as a means of hydrogen storage on-board fuel cell powered vehicles. For each technology area, we reviewed the open literature with respect to the following criteria: process efficiency, cost, safety, and ease of implementation and impact of the latest materials innovations, if any. We employed various process analysis platforms including FactSage chemical equilibrium software and Aspen Technologies AspenPlus and HYSYS chemical process simulation programs for determining the performance of the prospective hydrogen production processes.
Date: January 14, 2005
Creator: T-Raissi, Ali
Object Type: Report
System: The UNT Digital Library
Yucca Mountain Project - Science & Technology Radionuclide Absorbers Development Program Overview (open access)

Yucca Mountain Project - Science & Technology Radionuclide Absorbers Development Program Overview

The proposed Yucca Mountain repository is anticipated to be the first facility for long-term disposal of commercial spent nuclear fuel and high-level radioactive waste in the United States. The facility, located in the southern Nevada desert, is currently in the planning stages with initial exploratory excavations completed. It is an underground facility mined into the tuffaceous volcanic rocks that sit above the local water table. The focus of the work described in this paper is the development of radionuclide absorbers or ''getter'' materials for neptunium (Np), iodine (I), and technetium (Tc) for potential deployment in the repository. ''Getter'' materials retard the migration of radionuclides through sorption, reduction, or other chemical and physical processes, thereby slowing or preventing the release and transport of radionuclides. An overview of the objectives and approaches utilized in this work with respect to materials selection and modeling of ion ''getters'' is presented. The benefits of the ''getter'' development program to the United States Department of Energy (US DOE) are outlined.
Date: January 14, 2005
Creator: Jow, Hong-Nian; Moore, Robert C.; Helean, Katheryn B.; Mattigod, Shas; Hochella, Michael, Jr.; Felmy, Andrew R. et al.
Object Type: Report
System: The UNT Digital Library
Automatic Generation of Data Types for Classification of Deep Web Sources (open access)

Automatic Generation of Data Types for Classification of Deep Web Sources

A Service Class Description (SCD) is an effective meta-data based approach for discovering Deep Web sources whose data exhibit some regular patterns. However, it is tedious and error prone to create an SCD description manually. Moreover, a manually created SCD is not adaptive to the frequent changes of Web sources. It requires its creator to identify all the possible input and output types of a service a priori. In many domains, it is impossible to exhaustively list all the possible input and output data types of a source in advance. In this paper, we describe machine learning approaches for automatic generation of the data types of an SCD. We propose two different approaches for learning data types of a class of Web sources. The Brute-Force Learner is able to generate data types that can achieve high recall, but with low precision. The Clustering-based Learner generates data types that have a high precision rate, but with a lower recall rate. We demonstrate the feasibility of these two learning-based solutions for automatic generation of data types for citation Web sources and presented a quantitative evaluation of these two solutions.
Date: February 14, 2005
Creator: Ngu, A. H.; Buttler, D. J. & Critchlow, T. J.
Object Type: Article
System: The UNT Digital Library
Cost-Effective Sampling of Groundwater Monitoring Wells: A Data Review & Well Frequency Evaluation (open access)

Cost-Effective Sampling of Groundwater Monitoring Wells: A Data Review & Well Frequency Evaluation

Lawrence Livermore National Laboratory (LLNL) uses the Cost-Effective Sampling (CES) program for reviewing groundwater data and optimizing the site's groundwater monitoring plan. The CES program produces a data assessment sheet and a lowest-frequency sampling schedule for each groundwater monitoring location. The assessment sheet and recommended sampling schedule greatly streamline the data review process and provide useful information for regulatory and remedial decision-making. The determination of sampling frequency for a given location is based on trend, variability, and magnitude statistics. The underlying principle is that a location's schedule should be determined primarily by the rate of change in concentrations observed there in the recent past. The larger the rate of change, whether upward or downward, the greater the need for frequent sampling. Conversely, where little change is observed, less sampling is recommended. In 1992, CES was approved by the U.S. EPA - Region IX and the local regulators for use at LLNL, and became part of the LLNL's approved compliance monitoring plan (Lamarre et al. 1996). Applying the CES methodology produced, initially, a 40% reduction in the annual number of required groundwater samples, and with recent optimization of the program a 55% reduction has been produced. This reduction saves LLNL $530,000 …
Date: February 14, 2005
Creator: Ridley, M. & MacQueen, D.
Object Type: Article
System: The UNT Digital Library
DESIGN OF A CONCRETE SLAB FOR STORAGE OF SNF AND HLW CASKS (open access)

DESIGN OF A CONCRETE SLAB FOR STORAGE OF SNF AND HLW CASKS

This calculation documents the design of the Spent Nuclear Fuel (SNF) and High-Level Waste (HLW) Cask storage slab for the Aging Area. The design is based on the weights of casks that may be stored on the slab, the weights of vehicles that may be used to move the casks, and the layout shown on the sketch for a 1000 Metric Ton of Heavy Metal (MTHM) storage pad on Attachment 2, Sht.1 of the calculation 170-C0C-C000-00100-000-00A (BSC 2004a). The analytical model used herein is based on the storage area for 8 vertical casks. To simplify the model, the storage area of the horizontal concrete modules and their related shield walls is not included. The heavy weights of the vertical storage casks and the tensile forces due to pullout at the anchorages will produce design moments and shear forces that will envelope those that would occur in the storage area of the horizontal modules. The design loadings will also include snow and live loads. In addition, the design will also reflect pertinent geotechnical data. This calculation will document the preliminary thickness and general reinforcing steel requirements for the slab. This calculation also documents the initial design of the cask anchorage. Other …
Date: February 14, 2005
Creator: Bisset, J.
Object Type: Report
System: The UNT Digital Library
Diode-Laser Phase Conjugation 03-FS-030 Final Report (open access)

Diode-Laser Phase Conjugation 03-FS-030 Final Report

Arrays of lasers are often considered when a need exists to increase laser optical output power, for a variety of purposes. Similarly, individual semiconductor laser-diodes, generating 0.01-1.0 W each, are commonly placed in arrays in order to increase total optical power onto targeted objects. Examples of such usage are diode-laser pump arrays for solid-slab heat-capacity lasers, laser arrays for heat-treating materials, and arrays for efficient solid state laser systems. The commercial and defense communities also use such arrays for many applications from laser range-finders, laser designators, to laser machining systems, etc. However, the arraying process does not automatically increase ''focusable'' light on target (i.e., intensity/steradian). For those applications requiring the highest focusability, it is necessary that the collective output beam from arrays of individual lasers be phase-coherent. Under this condition, the individual laser-element optical outputs are ''fused together'' into a larger area, phase coherent (i.e., all wavefronts are ''in step''), high-power combined beam. The process of joining multiple laser beams together to produce a single coherent wave, is in general very difficult and seldom accomplished. Thus joining together many hundreds to thousands of beams from individual laser-diodes, in large arrays, is still an unsolved problem. There are 2 major reasons …
Date: February 14, 2005
Creator: Page, R H; Beach, R J; Payne, S A & Holzrichter, J F
Object Type: Report
System: The UNT Digital Library
Domain-specific Web Service Discovery with Service Class Descriptions (open access)

Domain-specific Web Service Discovery with Service Class Descriptions

This paper presents DynaBot, a domain-specific web service discovery system. The core idea of the DynaBot service discovery system is to use domain-specific service class descriptions powered by an intelligent Deep Web crawler. In contrast to current registry-based service discovery systems--like the several available UDDI registries--DynaBot promotes focused crawling of the Deep Web of services and discovers candidate services that are relevant to the domain of interest. It uses intelligent filtering algorithms to match services found by focused crawling with the domain-specific service class descriptions. We demonstrate the capability of DynaBot through the BLAST service discovery scenario and describe our initial experience with DynaBot.
Date: February 14, 2005
Creator: Rocco, Daniel; Caverlee, James; Liu, Ling & Critchlow, Terence J.
Object Type: Article
System: The UNT Digital Library
Drift Compression and Final Focus for Intense Heavy Ion Beams with Non-periodic, Time-dependent Lattice (open access)

Drift Compression and Final Focus for Intense Heavy Ion Beams with Non-periodic, Time-dependent Lattice

In the currently envisioned configurations for heavy ion fusion, it is necessary to longitudinally compress the beam bunches by a large factor after the acceleration phase. Because the space-charge force increases as the beam is compressed, the beam size in the transverse direction will increase in a periodic quadrupole lattice. If an active control of the beam size is desired, a larger focusing force is needed to confine the beam in the transverse direction, and a non-periodic quadrupole lattice along the beam path is necessary. In this paper, we describe the design of such a focusing lattice using the transverse envelope equations. A drift compression and final focus lattice should focus the entire beam pulse onto the same focal spot on the target. This is difficult with a fixed lattice, because different slices of the beam may have different perveance and emittance. Four time-dependent magnets are introduced in the upstream of drift compression to focus the entire pulse onto the sam e focal spot. Drift compression and final focusing schemes are developed for a typical heavy ion fusion driver and for the Integrated Beam Experiment (IBX) being designed by the Heavy Ion Fusion Virtual National Laboratory.
Date: February 14, 2005
Creator: Qin, Hong; Davidson, Ronald C.; Barnard, John J. & Lee, Edward P.
Object Type: Report
System: The UNT Digital Library
Drift Compression and Final Focus Options for Heavy Ion Fusion (open access)

Drift Compression and Final Focus Options for Heavy Ion Fusion

A drift compression and final focus lattice for heavy ion beams should focus the entire beam pulse onto the same focal spot on the target. We show that this requirement implies that the drift compression design needs to satisfy a self-similar symmetry condition. For un-neutralized beams, the Lie symmetry group analysis is applied to the warm-fluid model to systematically derive the self-similar drift compression solutions. For neutralized beams, the 1-D Vlasov equation is solved explicitly, and families of self-similar drift compression solutions are constructed. To compensate for the deviation from the self-similar symmetry condition due to the transverse emittance, four time-dependent magnets are introduced in the upstream of the drift compression such that the entire beam pulse can be focused onto the same focal spot.
Date: February 14, 2005
Creator: Qin, Hong; Davidson, Ronald C.; Barnard, John J. & Lee, Edward P.
Object Type: Report
System: The UNT Digital Library
Estimating Liquid Fluxes in Thermally Perturbed Fractured Rock Using Measured Temperature Profiles (open access)

Estimating Liquid Fluxes in Thermally Perturbed Fractured Rock Using Measured Temperature Profiles

A new temperature-profile method was recently developed for analyzing perturbed flow conditions in superheated porous media. The method uses high-resolution temperature data to estimate the magnitude of the heat-driven liquid and gas fluxes that form as a result of boiling, condensation, and recirculation of pore water. In this paper, we evaluate the applicability of this new method to the more complex flow behavior in fractured formations with porous rock matrix. In such formations, with their intrinsic heterogeneity, the porous but low-permeable matrix provides most of the mass and heat storage capacity, and dominates conductive heat transfer, Fractures, on the other hand, offer highly effective conduits for gas and liquid flow, thereby generating significant convective heat transfer. After establishing the accuracy of the temperature-profile method for fractured porous formations, we apply the method in analyzing the perturbed flow conditions in a large-scale underground heater test conducted in unsaturated fractured porous tuff. The flux estimates for this test indicate a significant reflux of water near the heat source, on the order of a few hundred millimeter per year-much larger than the ambient percolation flux of only a few millimeter per year.
Date: February 14, 2005
Creator: Birkholzer, J.T.
Object Type: Report
System: The UNT Digital Library
Estimating Liquid Fluxes in Thermally Perturbed Fractured RockUsing Measured Temperature Profiles (open access)

Estimating Liquid Fluxes in Thermally Perturbed Fractured RockUsing Measured Temperature Profiles

None
Date: February 14, 2005
Creator: Birkholzer, Jens T.
Object Type: Article
System: The UNT Digital Library
Evaluation of Nevada Test Site Ground Motion and Rock Property Data to Bound Ground Motions at the Yucca Mountain Repository (open access)

Evaluation of Nevada Test Site Ground Motion and Rock Property Data to Bound Ground Motions at the Yucca Mountain Repository

Yucca Mountain licensing will require estimation of ground motions from probabilistic seismic hazard analyses (PSHA) with annual probabilities of exceedance on the order of 10{sup -6} to 10{sup -7} per year or smaller, which correspond to much longer earthquake return periods than most previous PSHA studies. These long return periods for the Yucca Mountain PSHA result in estimates of ground motion that are extremely high ({approx} 10 g) and that are believed to be physically unrealizable. However, there is at present no generally accepted method to bound ground motions either by showing that the physical properties of materials cannot maintain such extreme motions, or the energy release by the source for such large motions is physically impossible. The purpose of this feasibility study is to examine recorded ground motion and rock property data from nuclear explosions to determine its usefulness for studying the ground motion from extreme earthquakes. The premise is that nuclear explosions are an extreme energy density source, and that the recorded ground motion will provide useful information about the limits of ground motion from extreme earthquakes. The data were categorized by the source and rock properties, and evaluated as to what extent non-linearity in the material has …
Date: February 14, 2005
Creator: Hutchings, L. J.; Foxall, W.; Rambo, J. & Wagoner, J. L.
Object Type: Report
System: The UNT Digital Library