In this article, the authors study the transport of information between two complex systems with similar properties.

The U.S. Department of Energy (DOE) is interested in developing tools and methods for use in designing and evaluating safeguards systems for current and future plants in the nuclear power fuel cycle. The DOE is engaging several DOE National Laboratories in efforts applied to safeguards for chemical conversion plants and gaseous centrifuge enrichment plants. As part of the development, Lawrence Livermore National Laboratory has developed an integrated safeguards system analysis tool (LISSAT). This tool provides modeling and analysis of facility and safeguards operations, generation of diversion paths, and evaluation of safeguards system effectiveness. The constituent elements of diversion scenarios, including material extraction and concealment measures, are structured using directed graphs (digraphs) and fault trees. Statistical analysis evaluates the effectiveness of measurement verification plans and randomly timed inspections. Time domain simulations analyze significant scenarios, especially those involving alternate time ordering of events or issues of timeliness. Such simulations can provide additional information to the fault tree analysis and can help identify the range of normal operations and, by extension, identify additional plant operational signatures of diversions. LISSAT analyses can be used to compare the diversion-detection probabilities for individual safeguards technologies and to inform overall strategy implementations for present and future plants. …

Laser ablation has proven to be an effective method for generating nanoparticles; particles are produced in the laser induced vapor plume during the cooling stage. To understand the in-situ condensation process, a series of time resolved light scattering images were recorded and analyzed. Significant changes in the condensation rate and the shape of the condensed aerosol plume were observed in two background gases, helium and argon. The primary particle shape and size distribution were measured using a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a differential mobility analyzer (DMA). The gas dynamics simulation included nucleation and coagulation within the vapor plume, heat and mass transfer from the vapor plume to the background gas, and heat transfer to the sample. The experimental data and the calculated evolution of the shape of the vapor plume showed the same trend for the spatial distribution of the condensed particles in both background gases. The simulated particle size distribution also qualitatively agreed with the experimental data. It was determined that the laser energy, the physical properties of the background gas (conductivity, diffusivity and viscosity), and the shape of the ablation system (ablation chamber and the layout of the sample) have strong effects …

We currently use the CORSICA integrated modeling code for scenario studies for both the DIII-D and ITER experiments. In these simulations, free- or fixed-boundary equilibria are simultaneously converged with thermal evolution determined from transport models providing temperature and current density profiles. Using a combination of fixed boundary evolution followed by free-boundary calculation to determine the separatrix and coil currents. In the free-boundary calculation, we use the state-space controller representation with transport simulations to provide feedback modeling of shape, vertical stability and profile control. In addition to a tightly coupled calculation with simulator and controller imbedded inside CORSICA, we also use a remote procedure call interface to couple the CORSICA non-linear plasma simulations to the controller environments developed within the Mathworks Matlab/Simulink environment. We present transport simulations using full shape and vertical stability control with evolution of the temperature profiles to provide simulations of the ITER controller and plasma response.

Geologic storage of CO2 can be a viable technology forreducing atmospheric emissions of greenhouse gases only if it can bedemonstrated that leakage from proposed storage reservoirs and associatedhazards are small or can be mitigated. Risk assessment must evaluatepotential leakage scenarios and develop a rational, mechanisticunderstanding of CO2 behavior during leakage. Flow of CO2 may be subjectto positive feedbacks that could amplify leakage risks and hazards,placing a premium on identifying and avoiding adverse conditions andmechanisms. A scenario that is unfavorable in terms of leakage behavioris formation of a secondary CO2 accumulation at shallow depth. This paperdevelops a detailed numerical simulation model to investigate CO2discharge from a secondary accumulation, and evaluates the role ofdifferent thermodynamic and hydrogeologic conditions. Our simulationsdemonstrate self-enhancing as well as self-limiting feedbacks.Condensation of gaseous CO2, 3-phase flow of aqueous phase -- liquid CO2-- gaseous CO2, and cooling from Joule-Thomson expansion and boiling ofliquid CO2 are found to play important roles in the behavior of a CO2leakage system. We find no evidence that a subsurface accumulation of CO2at ambient temperatures could give rise to a high-energy discharge, aso-called "pneumatic eruption."

Consider the linear system Ax = b, where A is a large, sparse, real, symmetric, and positive definite matrix and b is a known vector. Solving this system for unknown vector x using a smoothed aggregation multigrid (SA) algorithm requires a characterization of the algebraically smooth error, meaning error that is poorly attenuated by the algorithm's relaxation process. For relaxation processes that are typically used in practice, algebraically smooth error corresponds to the near-nullspace of A. Therefore, having a good approximation to a minimal eigenvector is useful to characterize the algebraically smooth error when forming a linear SA solver. This paper discusses the details of a generalized eigensolver based on smoothed aggregation (GES-SA) that is designed to produce an approximation to a minimal eigenvector of A. GES-SA might be very useful as a standalone eigensolver for applications that desire an approximate minimal eigenvector, but the primary aim here is for GES-SA to produce an initial algebraically smooth component that may be used to either create a black-box SA solver or initiate the adaptive SA ({alpha}SA) process.

We describe a method for generating molecular hydrogen directly from the charge separation effected via rapid flow of liquid water through a metal orifice, wherein the input energy is the hydrostatic pressure times the volume flow rate. Both electrokinetic currents and hydrogen production rates are shown to follow simple equations derived from the overlap of the fluid velocity gradient and the anisotropic charge distribution resulting from selective adsorption of hydroxide ions to the nozzle surface. Pressure-driven fluid flow shears away the charge balancing hydronium ions from the diffuse double layer and carries them out of the aperture. Downstream neutralization of the excess protons at a grounded target electrode produces gaseous hydrogen molecules. The hydrogen production efficiency is currently very low (ca. 10-6) for a single cylindrical jet, but can be improved with design changes.

We report on electron emission and defect formation in theinteraction between slow (v~;0.3 vBohr) highly charged ions (SHCI) withinsulating (type IIa) and semiconducting (type IIb) diamonds. Electronemission induced by 31Pq+ (q=5 to 13), and 136Xeq+ (q=34 to 44) withkinetic energies of 9 kVxq increase linearly with the ion charge states,reaching over 100 electrons per ion for high xenon charge states withoutsurface passivation of the diamond with hydrogen. Yields from bothdiamond types are up to a factor of two higher then from reference metalsurfaces. Crater like defects with diameters of 25 to 40 nm are formed bythe impact of single Xe44+ ions. High secondary electron yields andsingle ion induced defects enable the formation of single dopant arrayson diamond surfaces.

The fully nonlinear 4D TEMPEST gyrokinetic continuum code produces frequency, collisionless damping of geodesic-acoustic mode (GAM) and zonal flow with fully nonlinear Boltzmann electrons for the inverse aspect ratio {epsilon}-scan and the tokamak safety factor q-scan in homogeneous plasmas. The TEMPEST simulation shows that GAM exists in edge plasma pedestal for steep density and temperature gradients, and an initial GAM relaxes to the standard neoclassical residual, rather than Rosenbluth-Hinton residual due to the presence of ion-ion collisions. The enhanced GAM damping explains experimental BES measurements on the edge q scaling of the GAM amplitude.

As part of an ongoing effort at Lawrence Livermore National Laboratory (LLNL) to enhance analytical models that simulate enrichment and conversion facilities, efforts are underway to develop routines to estimate the total gamma-ray flux and that of specific lines around process piping containing UF{sub 6}. The intent of the simulation modeling effort is to aid in the identification of possible areas where material diversion could occur, as input to an overall safeguards strategy. The operation of an enrichment facility for the production of low enriched uranium (LEU) presents certain proliferation concerns, including both the possibility of diversion of LEU and the potential for producing material enriched to higher-than-declared, weapons-usable levels. Safeguards applied by the International Atomic Energy Agency (IAEA) are designed to provide assurance against diversion or misuse. Among the measures being considered for use is the measurement of radiation fields at various locations in the cascade hall. Our prior efforts in this area have focused on developing a model to predict neutron fields and how they would change during diversion of misuse. The neutron models indicated that while neutron detection useful in monitoring feed and product containers, it was not useful for monitoring process lines. Our current effort is …

We consider the energy accumulation in meta-stable clusters. This energy can be much larger than the typical chemical bond energy (~;;1 ev/atom). For example, polymeric nitrogen can accumulate 4 ev/atom in the N8 (fcc) structure, while helium can accumulate 9 ev/atom in the excited triplet state He2* . They release their energy by cluster fission: N8 -> 4N2 and He2* -> 2He. We study the locus of states in thermodynamic state space for the detonation of such meta-stable clusters. In particular, the equilibrium isentrope, starting at the Chapman-Jouguet state, and expanding down to 1 atmosphere was calculated with the Cheetah code. Large detonation pressures (3 and 16 Mbar), temperatures (12 and 34 kilo-K) and velocities (20 and 43 km/s) are a consequence of the large heats of detonation (6.6 and 50 kilo-cal/g) for nitrogen and helium clusters respectively. If such meta-stable clusters could be synthesized, they offer the potential for large increases in the energy density of materials.

Numerical simulation is used to evaluate mass flow and heatextraction rates from enhanced geothermal injection-production systemsthat are operated using either CO2 or water as heat transmission fluid.For a model system patterned after the European hot dry rock experimentat Soultz, we find significantly greater heat extraction rates for CO2 ascompared to water. The strong dependence of CO2 mobility (=density/viscosity) upon temperature and pressure may lead to unusualproduction behavior, where heat extraction rates can actually increasefor a time, even as the reservoir is subject to thermal depletion. Wepresent the first-ever three-dimensional simulations of CO2injection-production systems. These show strong effects of gravity onmass flow and heat extraction, due to the large contrast of CO2 densitybetween cold injection and hot production conditions. The tendency forpreferential flow of cold, dense CO2 along the reservoir bottom can leadto premature thermal breakthrough. The problem can be avoided byproducing from only a limited depth interval at the top of thereservoir.

Low cross section experiments to produce super-heavyelements have increased the demand for high intensity heavy ion beams atenergies of about 5 MeV/nucleon at the 88-Inch Cyclotron at the LawrenceBerkeley National Laboratory. Therefore, efforts are underway to increasethe overall ion beam transmission through the axial injection line andthe cyclotron. The ion beam emittance has been measured for various ionmasses and charge states. Beam transport simulations including spacecharge effects were performed for both of the injection line and the ionsource extraction. The relatively low nominal injection voltage of 10 kVwas found to be the main factor for ion beam losses, because of beam blowup due to space charge forces at higher intensities. Consequently,experiments and simulations have been performed at higherinjectionenergies, and it was demonstrated that the ion beams could still becentered in the cyclotron at these energies. Therefore, the new injectorion source VENUS and its ion beam transport system (currently underconstruction at the 88-Inch Cyclotron) are designed for extractionvoltages up to 30 kV.

Atomics International and Lawrence Livermore Laboratory are involved in the conceptual design of a laser fusion power plant incorporating the lithium fall target chamber. In this paper we discuss some of the more important design considerations for the target chamber and evaluate its nuclear performance. Sizing and configuration of the fall, hydraulic effects, and mechanical design considerations are addressed. The nuclear aspects examined include tritium breeding, energy deposition, and radiation damage.

We have used a temperature programmed, gas evolution technique to compare H{sub 2}S from coal and from pyrite in the presence of minerals or polymers. Pyrite decomposition in coal with H{sub 2}S release can be observed directly only if carbonate minerals, particularly iron-containing carbonates, are absent. Two distinct chemical mechanisms are required to model conversion of pyrite in coal to H{sub 2}S and pyrrhotite. Initially a reaction at pyrite grain surfaces (shrinking core model) occurs that is controlled by the rate of iron movement toward crystallite centers and by hydrogen-donor availability. Tar evolution (as indicated by methane-plus-ethane) also requires H-donors. Organic free radicals compete so efficiently for this scarce commodity that the rate of pyrite decomposition slows. At a 10 K/min heating rate, the rate of H{sub 2}S release by the H-donor mechanism reaches a maximum at 700 K and then decreases. Unimolecular decomposition of coal pyrite to FeS and S{sub 2} then occurs sharply at 830 K. Coal pyrolysis products effectively capture S{sub 2}, and the rate of H{sub 2}S release matches that of sulfur release from pure pyrite in a vacuum (0.07 mg- S/cm{sup 2}/min at 773 K). The high temperature H{sub 2}S evolution peak from coal is …

This paper briefly deals with the problem of narrow band materials. It addresses a new theoretical approach to the fluctuation of valence electrons in rare earth elements. It is believed that the phenomena of interest arize from an instability of the partially filled d or f shell of certain atoms when they are put into a metallic host. The theoretical models which dominate the scene work with two local d or f states on one hand and a structureless sea of free conduction electrons on the other. This procedure ignores at least half of the essential physics; the other held is kept alive in the term valence fluctuation. Basically, what the prevalent models ignore is that, in all these systems, the entire atoms as the source of the anomalies are being dealt with, not just their f shells. In other words, there is important structure in the sea of conduction electrons.

An electron beam machine consisting of six modules is being constructed for the 'B' amplifier of the RAPIER KrF laser system. Each module consists of a diode, a 5 ..cap omega.. positive charged water dielectric Blumlein pulse-forming line, and a five stage Marx generator. Separate 25 cm x 41 cm electron beams are formed in magnetically isolated diodes which when arranged in groups of three produce two nearly continuous 25 cm x 125 cm beams that enter the laser cell from opposite sides. The pulse-forming lines operate at 450 keV and produce 150 ns long pulses. The lines employ electrically triggered annular SF/sub 6/ output switches. The two concentric transmission lines of each pulse-forming line are charged in 1 ..mu..s through symmetric circuits to reduce diode prepulse voltage. The six modules together with the laser cell will occupy less than 15 m/sup 2/ of floor space.

An attempt was made to pursue [sup 129]Xe NMR as a pore measurement technique. Samples studied were synthetic imogolite (tubular aluminosilicate with gibbsite structure), sodium Y-zeolite, and an aerogel and a xerogel. Gases used were normal Xe, [sup 13]CO[sub 2], and [sup 15]N[sub 2]. Although a completely general NMR technique for measuring pore size distributions may not be possible, information about molecular motion and interactions can be obtained, because NMR is sensitive to short range interactions (1 nm or less) and to molecular dynamics in the range 10[sup [minus]2] to 10[sup [minus]6]s.

One of the most difficult technology problems in an inertially confined fusion reactor is the survival of the structure from the repeated stresses caused by the microexplosion products. To mitigate the damage from the microexplosion products, a thick lithium fall can be circulated in front of the structure. This fall will absorb the short-ranged products and moderate and attenuate the neutrons. This paper discusses the response of the fall to the microexplosion products, and estimates the resulting loading and stresses in the first structural wall.

An attempt was made to pursue {sup 129}Xe NMR as a pore measurement technique. Samples studied were synthetic imogolite (tubular aluminosilicate with gibbsite structure), sodium Y-zeolite, and an aerogel and a xerogel. Gases used were normal Xe, {sup 13}CO{sub 2}, and {sup 15}N{sub 2}. Although a completely general NMR technique for measuring pore size distributions may not be possible, information about molecular motion and interactions can be obtained, because NMR is sensitive to short range interactions (1 nm or less) and to molecular dynamics in the range 10{sup {minus}2} to 10{sup {minus}6}s.

The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and also be amenable to two-dimensional modeling. Low level reaction thresholds occur at impact velocities below those required for shock initiation. To assist in understanding this test, multi-dimensional gauge techniques utilizing carbon foil and carbon resistor gauges were used to measure pressure and event times. Carbon resistor gauges indicated late time low level reactions 200-540 {micro}s after projectile impact, creating 0.39-2.00 kb peak shocks centered in PBX 9501 explosives discs and a 0.60 kb peak shock in a LX-04 disk. Steven Test modeling results, based on ignition and growth criteria, are presented for two PBX 9501 scenarios: one with projectile impact velocity just under threshold (51 m/s) and one with projectile impact velocity just over threshold (55 m/s). Modeling results are presented and compared to experimental data.

Single solid-state devices or arrays of solid-state devices are being incorporated into many pulsed power applications as a means of generating fast, high-power, high repetition-rate pulses and ultimately replacing hard tubes and thyratrons. While vendors' data sheets provide a starting point for selecting solid-state devices, most data sheets do not have sufficient information to determine performance in a pulsed application. To obtain this relevant information, MOSFET's and IGBT's from a number of vendors have been tested to determine rise times, fall times and current handling capabilities. The emphasis is on the evaluation of devices that can perform in the range of 100ns pulse widths and the test devices must be capable of switching 1000 volts or greater at a pulsed current of at least 25 amperes. Additionally, some devices were retest with a series magnetic switch to evaluate the effects on switching parameters and specifically rise times. All devices were evaluated under identical conditions and the complete test results are presented.

Hydrogen reacts with a uranium surface to form a fine, pyrophoric metal power (UH{sub 3}). Few spectroscopic studies have been conducted to study this reaction. Advances in Raman spectroscopy permit the application of the Raman method to formally difficult areas of chemistry such as the hydrogen corrosion of uranium: availability of multiple laser excitation wavelengths; fiber optics delivery and collection systems; upgraded instrumentation and detection techniques; and development of special enclosed in situ reactor cells. UH{sub 3} vibrations are expected to occur at low frequencies due to extended U-H-U structure.

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