Water fluxes in unsaturated, fractured rock involve the physical processes occurring at fracture-matrix interfaces within fracture networks. Modeling these water fluxes using a discrete fracture network model is a complicated effort. Existing preprocessors for TOUGH2 are not suitable to generate grids for fracture networks with various orientations and inclinations. There are several 3-D discrete-fracture-network simulators for flow and transport, but most of them do not capture fracture-matrix interaction. We have developed a new 3-D discrete-fracture-network mesh generator, FRACMESH, to provide TOUGH2 with information about the fracture network configuration and fracture-matrix interactions. FRACMESH transforms a discrete fracture network into a 3 dimensional uniform mesh, in which fractures are considered as elements with unique rock material properties and connected to surrounding matrix elements. Using FRACMESH, individual fractures may have uniform or random aperture distributions to consider heterogeneity. Fracture element volumes and interfacial areas are calculated from fracture geometry within individual elements. By using FRACMESH and TOUGH2, fractures with various inclinations and orientations, and fracture-matrix interaction, can be incorporated. In this paper, results of flow and transport simulations in a fractured rock block utilizing FRACMESH are presented.

The Defense Threat Reduction Agency, DTRA, is a federal agency charged with safeguarding the nation from weapons of mass destruction, in particular nuclear weapons such as crude devices, and radiological dispersal devices (RDD), also known as dirty bombs. Both of which could be delivered using unconventional means such as by transporting them by a car or boat. Two years ago DTRA partnered with NNSA to evaluate commercially available technologies that could be deployed quickly to defend against threats posed by unconventional nuclear weapons under a program called the Unconventional Nuclear Warfare Defense (UNWD) Program. Lawrence Livermore National Laboratory (LLNL) was one of several National laboratories that participated in this program, which consisted in developing, deploying, and demonstrating detection systems suitable for military base protection. Two key contributions to this program by the LLNL team were the development of two Radiation Detection Buoys (RDB) deployed at Naval Base in Kings Bay in Georgia, and the Detection and Tracking System (DTS) demonstrated at Fort Leonard Wood Missouri, headquarters for the Total Force's Maneuver Support Center (MANSCEN). The RDB's were designed to detect the potential transportation of an unconventional nuclear or radiological weapon by a boat. The RDB's consisted of two commercial marine …

During the 2007 calendar year, Lawrence Livermore National Laboratory (LLNL) provided health physics support for the Highly Enriched Uranium (HEU) Transparency Program for external and internal radiation protection and technical expertise related to BDMS radioactive sources and Russian radiation safety regulatory compliance. For the calendar year 2007, there were 172 person-trips that required dose monitoring of the U.S. monitors. Of the 172 person-trips, 160 person-trips were SMVs and 12 person-trips were Transparency Monitoring Office (TMO) trips. There were 12 monitoring visits by TMO monitors to facilities other than UEIE and 10 to UEIE itself. There were two monitoring visits (source changes) that were back to back with 14 monitors. LLNL's Hazard Control Division laboratories provided the dosimetry services for the HEU Transparency monitors.

Our ability to simulate physical processes numerically is constrained by our ability to solve the resulting linear systems, prompting substantial research into the development of multiscale iterative methods capable of solving these linear systems with an optimal amount of effort. Overcoming the limitations of geometric multigrid methods to simple geometries and differential equations, algebraic multigrid methods construct the multigrid hierarchy based only on the given matrix. While this allows for efficient black-box solution of the linear systems associated with discretizations of many elliptic differential equations, it also results in a lack of robustness due to assumptions made on the near-null spaces of these matrices. This paper introduces an extension to algebraic multigrid methods that removes the need to make such assumptions by utilizing an adaptive process. The principles which guide the adaptivity are highlighted, as well as their application to algebraic multigrid solution of certain symmetric positive-definite linear systems.

To achieve high focal spot intensities in heavy ion fusion, the ion beam must be compressed longitudinally by factors of ten to one hundred before it is focused onto the target. The longitudinal compression is achieved by imposing an initial velocity profile tilt on the drifting beam. In this paper, the problem of longitudinal drift compression of intense charged particle beams is solved analytically for the two important cases corresponding to a cold beam, and a pressure-dominated beam, using a one-dimensional warm-fluid model describing the longitudinal beam dynamics.

The production and handling in 1999 of about 200 million kilograms of bromine plus substantial derivatives thereof by Great Lakes Chemical Corp. and Albemarle Corporation in their southern Arkansas refineries gave OSHA Occupational Injury/Illness Rates (OIIR) in the range of 0.74 to 1.60 reportable OIIRs per 200,000 man hours. OIIRs for similar industries and a wide selection of other U.S. industries range from 1.6 to 23.9 in the most recent OSHA report. Occupational fatalities for the two companies in 1999 were zero compared to a range in the U.S.of zero for all computer manufacturing to 0.0445 percent for all of agriculture, forestry and fishing in the most recent OSHA report. These results show that bromine and its compounds can be considered as safe chemicals as a result of the bromine safety standards and practices at the two companies. The use of hydrobromic acid as an electrical energy storage medium in reversible PEM fuel cells is discussed. A study in 1979 of 20 megawatt halogen working fluid power plants by Oronzio de Nora Group found such energy to cost 2 to 2.5 times the prevailing base rate at that time. New conditions may reduce this relative cost. The energy storage aspect …

We examine various options for calibration of NIF neutron detectors in the energy region E<14 MeV. These options include: downscatter of D-T fusion neutrons using plastic targets; nuclear reactions at a Tandem Van de Graaf accelerator; and ''white'' neutrons from a pulsed spallation source. As an example of the spallation option, we present some calibration data that was recently obtained with a single crystal CVD diamond detector at the Weapons Neutron Research facility (WNR) at LANL.

LLM-105 (2,6-diamino-3,5-dinitropyrazine-1-oxide) is a new molecule which has performance and insensitivity between those of HMX and TATB. Its calculated energy content is about 85% that of HMX and 15% more than that of TATB. It is thermally stable, insensitive to shock, spark and friction and has impact insensitivity level approaching that of TATB. These combined properties make it a realistic high-performance IHE material, attractive for applications that require moderate performance and insensitivity. Several morphologies of LLM-105 and plastic-bonded formulations containing these materials and another binder were prepared and characterized. Their physical properties and detonation spreading characteristics are compared to those of ultrafine TATB. The impact sensitivity (drop hammer results) is sensitive to particle morphologies. Detonation-spreading, spot-size tests on LLM-105 compositions showed higher energy output and superior divergence behavior than is observed for ultrafine TATB. The small-scale safety data, pressing characteristics and results from divergence experiments will be summarized.

We present first principles, computational predictions of a porous, nano-structured semiconductor material that will reversibly store hydrogen for fuel cell applications. The material is competitive with current metal hydride storage materials, but contains only carbon and silicon, reducing both its cost and environmental impact. Additionally, unlike metal hydrides, the core skeleton structure of this material is unaltered when cycling from full hydrogen storage to full hydrogen depletion, removing engineering complications associated with expansion/contraction of the material.

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We examine the effect of the collective force due to coherent synchrotron radiation (CSR) in an electron storage ring with small bending radius. In a computation based on time-domain integration of the nonlinear Vlasov equation, we find the threshold current for a longitudinal microwave instability induced by CSR alone. The model accounts for suppression of radiation at long wave lengths due to shielding by the vacuum chamber. In a calculation just above threshold, small ripples in the charge distribution build up over a fraction of a synchrotron period, but then die out to yield a relatively smooth but altered distribution with eventual oscillations in bunch length. The instability evolves from small noise on an initial smooth bunch of r.m.s.length much greater than the shielding cutoff. The paper includes a derivation and extensive analysis of the complete impedance function Z for synchrotron radiation with parallel plate shielding. We find corrections to the lowest approximation to the coherent force which involve ''off-diagonal'' values of Z, that is, fields with phase velocity not equal to the particle velocity.

We have constructed a regional 3D geologic model of the southern Great Basin, in support of a seismic wave propagation investigation of the 1993 Nonproliferation Experiment (NPE) at the Nevada Test Site (NTS). The model is centered on the NPE and spans longitude -119.5{sup o} to -112.6{sup o} and latitude 34.5{sup o} to 39.8{sup o}; the depth ranges from the topographic surface to 150 km below sea level. The model includes the southern half of Nevada, as well as parts of eastern California, western Utah, and a portion of northwestern Arizona. The upper crust is constrained by both geologic and geophysical studies, while the lower crust and upper mantle are constrained by geophysical studies. The mapped upper crustal geologic units are Quaternary basin fill, Tertiary deposits, pre-Tertiary deposits, intrusive rocks of all ages, and calderas. The lower crust and upper mantle are parameterized with 5 layers, including the Moho. Detailed geologic data, including surface maps, borehole data, and geophysical surveys, were used to define the geology at the NTS. Digital geologic outcrop data were available for both Nevada and Arizona, whereas geologic maps for California and Utah were scanned and hand-digitized. Published gravity data (2km spacing) were used to determine …

This Corrective Action Investigation Plan contains the U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office's approach to collect the data necessary to evaluate corrective action alternatives appropriate for the closure of Corrective Action Unit (CAU) 271 under the Federal Facility Agreement and Consent Order. Corrective Action Unit 271 consists of 15 Corrective Action Sites (CASs) including: thirteen Septic Systems (25-04-01, 25-04-03, 25-04-04, 25-04-08, 25-04-09, 25-04-10, 25-04-11, 26-04-01, 26-04-02, 26-05-03, 26-05-04, 26-05-05, and 27-05-02), one Contaminated Water Reservoir (26-03-01), and one Radioactive Leachfield (26-05-01). The CASs addressed by CAU 271 are located at Guard Station 500, the Reactor Control Point (RCP), Bare Reactor Experiment - Nevada Tower, and Engine Test State-1 (ETS-1) facilities in Area 25; the Port Gaston and Project Pluto facilities in Area 26; and the Baker Site in Area 27 of the Nevada Test Site. Between 1 958 and 1973, the RCP and ETS-1 facilities supported the development and testing of nuclear reactors for space propulsion as part of the Nuclear Rocket Development Station. The Project Pluto facilities supported nuclear reactor testing for use as a ramjet propulsion system between 1961 and 1964, followed by similar use for other projects through the early 1980s. The …

Medium carbon steel (MCS) is the candidate material for rock bolts to reinforce the borehole liners and emplacement drifts of the proposed Yucca Mountain (YM) high-level nuclear waste repository. Corrosion performance of this structural steel -AISI 1040- was investigated by techniques such as linear polarization, electrochemical impedance spectroscopy (EIS), and laboratory immersion tests in lab simulated concentrated YM ground waters. Corrosion rates of the steel were determined for the temperatures in the range from 25 C to 85 C, for the ionic concentrations of 1 time (1x), 10 times (10x), and hundred times (100x) ground waters. The MCS corroded uniformly at the penetration rates of 35-200 {micro}m/year in the de-aerated YM waters, and 200-1000 {micro}m/year in the aerated waters. Increasing temperatures in the de-aerated waters increased the corrosion rates of the steel. However, increasing ionic concentrations influenced the corrosion rates only slightly. In the aerated 1x and 10x waters, increasing temperatures increased the rates of MCS significantly. Inhibitive precipitates, which formed in the aerated 100x waters at higher temperatures (65 C and up) decreased the corrosion rates to the values that obtained for the de-aerated YM aqueous environments. The steel suffered pitting corrosion in the both de-aerated and aerated hot …

An approach using positron emission tomography (PET) was developed, validated and used to measure myocardial fatty acid metabolism in patients with inherited forms of heart failure. Abnormalities were correlated with the severity of the clinical illness. The approach developed was also shown to identify abnormalities in myocardial fatty acid metabolism in some patients with acquired forms of heart failure. The PET technique thus permits identification of abnormal fatty acid metabolism and provides an approach to evaluate the efficacy of interventional strategies.

A quasi one-dimensional (1-D) steady-state model of the Hall thruster is presented. For the same discharge voltage two operating regimes are possible -- with and without the anode sheath. For given mass flow rate, magnetic field profile and discharge voltage a unique solution can be constructed, assuming that the thruster operates in one of the regimes. However, we show that for a given temperature profile the applied discharge voltage uniquely determines the operating regime: for discharge voltages greater than a certain value, the sheath disappears. That result is obtained over a wide range of incoming neutral velocities, channel lengths and widths, and cathode plane locations. It is also shown that a good correlation between the quasi 1-D model and experimental results can be achieved by selecting an appropriate electron mobility and temperature profile.

Calculational assessment and experimental verification of certain neutron cross sections that are related to widely needed new medical isotopes. Experiments were performed at the Oregon State University TRIGA Reactor and the High Flux Irradiation Reactor at Oak Ridge National Laboratory.

Ap/Bp stars are magnetic chemically peculiar early A and late B type stars of the main sequence. They exhibit peculiar surface abundance anomalies that are thought to be the result of gravitational settling and radiative levitation. The physics of diffusion in these stars are reviewed briefly and some model predictions are discussed. While models reproduce some observations reasonably well, more work is needed before the behavior of diffusing elements in a complex magnetic field is fully understood.

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This study investigates the effects of uncertainty inrockphysics models on estimates of reservoir parameters from jointinversion of seismic AVA and CSEMdata. The reservoir parameters arerelated to electrical resistivity using Archie's law, and to seismicvelocity and density using the Xu-White model. To account for errors inthe rock-physics models, we use two methods to handle uncertainty: (1)the model outputs are random functions with modes or means given by themodel predictions, and (2) the parameters of the models are themselvesrandom variables. Using a stochastic framework and Markov Chain MonteCarlo methods, we obtain estimates of reservoir parameters as well as ofthe uncertainty in the estimates. Synthetic case studies show thatuncertainties in both rock-physics models and their associated parameterscan have significant effects on estimates of reservoir parameters. Ourmethod provides a means of quantifying how the uncertainty in theestimated reservoir parameters increases with increasing uncertainty inthe rock-physics model and in the model parameters. We find that in theexample we present, the estimation of water saturation is relatively lessaffected than is the estimation of clay content and porosity.

We have measured the production of hv {approx} 4.7 keV x-rays from low-density Ti-doped aerogel ({rho} {approx} 3 mg/cc) targets at the OMEGA laser facility (University of Rochester), with the goal of maximizing x-ray output. Forty OMEGA beams ({lambda}{sub L} = 0.351 {micro}m) illuminated the two cylindrical faces of the target with a total power that ranged from 7 to 14 TW. The laser fully ionizes the target (n{sub e}/n{sub crit} {le} 0.1), and a laser-bleaching wave excites, supersonically, the high-Z emitter ions in the sample. Heating in the target was imaged with gated x-ray framing cameras and an x-ray streak camera. Ti K-shell x-ray emission was spectrally resolved with a two-channel crystal spectrometer and also with a set of filtered aluminum x-ray diodes, both instruments provide absolute measurement of the multi-keV x-ray emission. We find between 40 - 260 J of output with 4.67 {le} hv {le} 5.0 keV. Radiation-hydrodynamic calculations predict late time enhancement of the x-ray power due first to axial stagnation of the heating waves, then, ablatively-driven radial compression from the target walls.

This report describes the electrochemical corrosion scans and conditions for testing of SY-102 supernatant samples taken December 2004. The testing was performed because the tank was under a Justification for Continued Operation allowing the supernatant composition to be outside the chemistry limits of Administrative Control 5.16, 'Corrosion Mitigation program'. A new electrochemical working electrode of A516 Grade 60 carbon steel was used for each scan; all scans were measured against a saturated calomel electrode, with carbon counter electrodes, and all scans were carried out at 50 C. The samples were scanned twice, once as received and once sparged with argon to deoxygenate the sample. For those scans conducted after argon purging, the corrosion rates ranged from 0.012 to 0.019 mpy. A test for stress corrosion cracking was carried out on one sample (2SY-04-07) with negative results.

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