GaInP/GaAs cells invented and developed at NREL have achieved world-record efficiencies. We estimate that their production for space applications has grown to > $100 million/yr. Approximately 300 MW/yr of 1000X terrestrial concentrator cells could be fabricated with the existing manufacturing capacity at a cost of about 21{cents}/Wp. A resurgence of interest in terrestrial PV concentrators, together with the strength of the III-V space-solar-cell industry, indicate that III-V cells are also attractive for terrestrial applications.

This paper describes the design process of physical security as applied to a U.S. Border Port of Entry (PoE). Included in this paper are descriptions of the elements that compose U.S. border security. The physical security design will describe the various elements that make up the process as well as the considerations that must be taken into account when dealing with system integration of those elements. The distinctions between preventing unlawful entry and exit of illegal contraband will be emphasized.

A study of the uncertainty in calculations of the rod ejection accident in a pressurized water reactor is being carried out for the US Nuclear Regulatory Commission. This paper is a progress report on that study. Results are presented for the sensitivity of core energy deposition to the key parameters: ejected rod worth, delayed neutron fraction, Doppler reactivity coefficient, and fuel specific heat. These results can be used in the future to estimate the uncertainty in local fuel enthalpy given some assumptions about the uncertainty in the key parameters. This study is also concerned with the effect of the intra-assembly representation in calculations. The issue is the error that might be present if assembly-average power is calculated, and pin peaking factors from a static calculation are then used to determine local fuel enthalpy. This is being studied with the help of a collaborative effort with Russian and French analysts who are using codes with different intra-assembly representations. The US code being used is PARCS which calculates power on an assembly-average basis. The Russian code being used is BARS which calculates power for individual fuel pins using a heterogeneous representation based on a Green's Function method.

light water reactors

We have deposited CdTe thin films by close-spaced sublimation at two different temperature ranges. The films deposited at the lower temperature partially recrystallized after CdCl2 treatment at 350 C and completely recrystallized after the same treatment at 400 C. The films deposited at higher temperature did not recrystallize at these two temperatures. These results confirmed that the mechanisms responsible for changes in physical properties of CdTe films treated with CdCl2 are recrystallization and grain growth, and provided an alternative method to deposit CSS films using lower temperatures.

Ion Beam Induced Charge Collection (IBICC) and Time Resolved IBICC (TRIBICC) techniques were e for imaging electronic properties of Cadmium Zinc Telluride (CZT) room temperature radiation detectors. The detectors were bombarded with a scanned 5.4 MeV He microbeam and the detector response was analyzed at each point. The electron mobility (A) and Metime (z.), and charge collection efficiency maps were calculated from the data. In order to determine the radiation damage to the detectors, the signal deteriomtion was measured as the function of dose.

A physical model is developed to quantify the contribution of oxide-trapped charge to enhanced low-dose-rate gain degradation in bipolar junction transistors. Multiple-trapping simulations show that space charge limited transport is partially responsible for low-dose-rate enhancement. At low dose rates, more holes are trapped near the silicon-oxide interface than at high dose rates, resulting in larger midgap voltage shifts at lower dose rates. The additional trapped charge near the interface may cause an exponential increase in excess base current, and a resultant decrease in current gain for some NPN bipolar technologies.

The US Nuclear Regulatory Commission (NRC) and the Federal Nuclear and Radiation Safety Authority of the Russian Federation have been working together since 1994 to carry out a probabilistic risk assessment (PRA) of a VVER-1000 in the Russian Federation. This was a recognition by both parties that this technology has had a profound effect on the discipline of nuclear reactor safety in the West and that the technology should be transferred to others so that it can be applied to Soviet-designed plants. The NRC provided funds from the Agency for International Development and technical support primarily through Brookhaven National Laboratory and its subcontractors. The latter support was carried out through workshops, by documenting the methodology to be used in a set of guides, and through periodic review of the technical activity. The result of this effort to date includes a set of procedure guides, a draft final report on the Level 1 PRA for internal events (excluding internal fires and floods), and progress reports on the fire, flood, and seismic analysis. It is the authors belief that the type of assistance provided by the NRC has been instrumental in assuring a quality product and transferring important technology for use by …

The novelty of this work is in presenting interesting error properties of two types of asymptotically optimal quadrilateral meshes for bilinear approximation. The first type of mesh has an error equidistributing property where the maximum interpolation error is asymptotically the same over all elements. The second type has faster than expected super-convergence property for certain saddle-shaped data functions. The super-convergent mesh may be an order of magnitude more accurate than the error equidistributing mesh. Both types of mesh are generated by a coordinate transformation of a regular mesh of squares. The coordinate transformation is derived by interpreting the Hessian matrix of a data function as a metric tensor. The insights in this work may have application in mesh design near known corner or point singularities.

None

Adherence of plasma-sprayed thermal barrier coatings (TBC'S} is strongly dependent on mechanical interlocking at the interface between the ceramic coating and the underlying metallic bond coat. Typically, a rough bond-coat surface topology is required to achieve adequate mechanical bonding. However, the resultant interfacial asperities modify the residual stresses that develop in the coating system due to thermal expansion differences, and other misfit strains, and generate stresses that can induce progressive fracture and eventual spallation of the ceramic coating. For a flat interface the principal residual stress is parallel to the interface as the stress normal to the interface is zero. However, the residual stress normal to the interface becomes non-zero, when the interface has the required interlocking morphology. In the present study, an actual microstructure of a plasma-sprayed TBC system was numerically simulated and analyzed with a recently developed, object-oriented finite element analysis program, OOF, to give an estimate of the localized residual stresses in a TBC system. Additionally, model TBC rnicrostructures were examined to evaluate the manner in which the topology of interfacial asperities influences residual stresses. Results are present for several scenarios of modifying interfacial roughness.

Damage to plasma-facing components (PFCS) from plasma instabilities remains a major obstacle to a successful tokamak concept. The extent of the damage depends on the detailed physics of the disrupting plasma, as well as on the physics of plasma-material interactions. A comprehensive computer package called High Energy Interaction with General Heterogeneous Target Systems (HEIGHTS) has been developed and consists of several integrated computer models that follow the beginning of a plasma disruption at the scrape-off layer (SOL) through the transport of the eroded debris and splashed target materials to nearby locations as a result of the deposited energy. The package can study, for the first time, plasma-turbulent behavior in the SOL and predict the plasma parameters and conditions at the divertor plate. Full two-dimensional (2-D) comprehensive radiation magnetohydrodynamic (MHD) models are coupled with target thermodynamics and liquid hydrodynamics to evaluate the integrated response of plasma-facing materials. Factors that influence the lifetime of plasma-facing and nearby components, such as loss of vapor-cloud confinement and vapor removal due to MHD effects, damage to nearby components due to intense vapor radiation, melt splashing, and brittle destruction of target materials, are also modeled and discussed.

For {sup 238}U targets and the five elements considered here, the best yields of neutron-rich isotopes are obtained from neutrons in the 2-20 MeV range. High energy beams of neutrons, protons, and deuterons have comparable integral yields per element to neutrons below 20 MeV, but the distributions are peaked at lower neutron numbers. This is presumably due to a higher neutron multiplicity in the pre-equilibrium stage and/or the compound nucleus/fission stage. For {sup 235}U targets there are high yields predicted especially for thermal neutrons, and also for the fast neutron spectrum. For the high energy neutrons, protons, and deuterons {sup 235}U has no advantage over {sup 238}U. A detailed comparison of the relative advantages of {sup 235}U and {sup 238}U for radioactive beam applications is beyond the scope of this study and will be addressed in the future. The present work is the first step of a more detailed analysis of various possible one- and two-step target geometry calculated with the LAHET code system. It is intended to serve as a guide in choosing geometry and beams for future studies. It is desirable to extend this study to higher beam energies, e.g. 200 to 1000 MeV, but at this time …

The phase transformation of {beta}-HMX (< 0.5% RDX) to the {delta} phase has been studied for over twenty years and more recently with an optically sensitive second harmonic generation technique. Shock studies of the plastic binder composites of HMX have indicated that the transition is perhaps irreversible, a result that concurs with the static pressure results published by F. Goetz et al. [l] in 1978. However the stability field favors the {beta} polymorph over {delta} as pressure is increased (up to 5.4 GPa) along any sensible isotherm. In this experiment strict control of pressure and temperature is maintained while x-ray and optical diagnostics are applied to monitor the conformational dynamics of HMX. Unlike the temperature induced {beta} -> {delta} transition, the pressure induced is heterogeneous in nature. The room pressure and temperature {delta} -> {beta} transition is not immediate although it seems to occur over tens of hours. Transition points and kinetics are path dependent and so this paper describes our work in progress.

Large-scale computer simulations, a hallmark of computing at Lawrence Livermore National Laboratory (LLNL), often take days to run and can produce massive amounts of output. The typical environment of many LLNL scientists includes multiple hardware platforms, a large collection of eclectic software applications, data stored on many devices in many formats, and little standard metadata, which is accessible documentation about the data. The exploration of simulation results typically proceeds as a laborious process requiring knowledge of this complex environment and many application programs. We have addressed this problem by developing a web-based approach for exploring simulation results via the automatic generation of metadata summaries which provide convenient access to the data sets and associated analysis tools. In this paper we will describe the SimTracker tool for automatically generating metadata that serves as a quick overview and index to the archived results of simulations. The SimTracker application consists of two parts - a generation component and a viewing component. The generation component captures and generates calculation metadata from a simulation. These metadata include graphical snapshots from various stages of the run, pointers to the input and output files from the simulation, and assorted annotations describing the run. SimTracker generation can be …

The thermodynamic and transport properties of crystals and fluids at high temperature and pressure play a central role in the Earth and planetary sciences as well as in a variety of technologies and constitute a principal probe into the internuclear potential energy function at high density. Observation of surface waves by coherent time-domain optical spectroscopy provides an experimental approach to the determination, in the diamond-anvil high-pressure cell, of the elastic constants and thermal diffusivity of metal crystals as well as the equation of state and thermal transport properties of fluids. The electrical resistivities of metals may also be approximately accessible via the Wiedemann Franz Law. Preliminary results on Ta to pressures of 5.2 GPa are reported here. [Ta, elasticity, sound velocity, thermal diffusivity, equation of state].

The three dimensional Arbitrary Lagrange Eulerian hydrodynamic computer code ALE3D with fully coupled thermal-chemical-mechanical material models provides the framework for the development of a physically realistic model of shock initiation and detonation of solid explosives. The processes of hot spot formation during shock compression, subsequent ignition of reaction or failure to react, growth of reaction in individual hot spots, and coalescence of reacting hot spots during the transition to detonation can now be modeled using Arrhenius chemical kinetic rate laws and heat transfer to propagate the reactive flow. This paper discusses the growth rates of reacting hot spots in HMX and TATB and their coalescence during shock to detonation transition. Hot spot deflagration rates are found to be fast enough to consume explosive particles less than 10 mm in diameter during typical shock duration times, but larger particles must fragment and create more reactive surface area in order to be rapidly consumed.

In K-edge densitometry (KED), a continuous-energy x-ray beam is transmitted through a liquid sample. The actinide content of the sample can be measured through analysis of the transmitted portion of the x-ray beam. Traditional methods for KED analysis allow the simultaneous calculation of, at most, two actinide concentrations. A generalized multi-edge KED analytical method is presented, allowing up to six actinide concentrations to be calculated simultaneously. Applications of this method for hybrid KED/x-ray fluorescence (HKED) systems are discussed. Current HKED systems require the operator to know the approximate actinide content of each sample, and manually select the proper analysis mode. The new multi-edge KED technique allows rapid identification of the major actinide components in a sample, independent of actinide content. The proper HKED analysis mode can be selected automatically, without requiring sample content information from the user. Automatic HKED analysis would be especially useful in an analytical laboratory setting, where samples with truly unknown characteristics are encountered. Because this technique requires no hardware modifications, several facilities that use HKED may eventually benefit from this approach.

In an effort to better characterize and classify austenitic stainless steel resistance upset welds, standard methods have been examined and alternative methods investigated. Optical microscopy yields subjective classification due to deformation obscured bond lines and individual perception. The use of specimen preparations that better reveal grain boundaries aids in substantiating optical information. Electron microscopy techniques produce quantitative information in relation to microstructural constituents. Orientation Imaging Microscopy (OIM) is a relatively new technique for obtaining objective, quantitative information pertaining to weld integrity, i.e., percent grain boundary growth across the interface.

Legacy plutonium residues often have inadequate item descriptions. Nondestructive characterization can help segregate these items for reprocessing or provide information needed for disposal or storage. Alpha particle-induced gamma-ray spectra contain a wealth of information that can be used for matrix characterization. We demonstrate how this information can be used for item identification. Gamma-ray spectra were recorded at the Los Alamos Plutonium Facility from a variety of legacy, plutonium-processing residues and product materials. The comparison and analysis of these spectra are presented.

This paper summarizes an analysis of the U.S.-Russian Nuclear Material Protection, Control and Accounting (MPC&A) Program, developed on the basis of extensive discussions with U.S. laboratory participants as well as personal experience. Results of the discussions have been organized into three main areas: Technical/MPC&A Progress; Programmatic and Administrative Issues; and Professional Aspects, Implications for MPC&A effectiveness, for MPC&A sustainability, and for future relations and collaboration are derived. Suggested next steps are given.

This paper summarizes an analysis of the US-Russian Nuclear Material Protection, Control and Accounting (MPC and A) Program, developed on the basis of extensive discussions with US laboratory participants as well as personal experience. Results of the discussions have been organized into three main areas: Technical/MPC and A Progress; Programmatic and Administrative Issues; and Professional Aspects, Implications for MPC and A effectiveness, for MPC and A sustainability, and for future relations and collaboration are derived. Suggested next steps are given.

Beam echos have been measured at FNAL [3] and CERN [5] in coasting beams. A coherent oscillation introduced by a short RF burst decoheres quickly, but a coherent echo of this oscillation can be observed if the decohered oscillation is ''bounced off'' a second RF burst. In this report we describe first longitudinal echo measurements of bunched beam in the AGS accelerator. We applied a method proposed by Stupakov [1] for transverse beam echos, where the initial oscillation is produced by a dipole kick and is bounced off a quadrupole kick. In the longitudinal case the dipole and quadrupole kicks are produced by a cavities operating at a 90{degree} and 0{degree} phase shift, respectively.

The understanding of crystalline beams has advanced to the point where one can now, with reasonable confidence, undertake an analysis of the luminosity of colliding crystalline beams. Such a study is reported here. It is necessary to observe the criteria, previously stated, for the creation and stability of crystalline beams. This requires, firstly, the proper design of a lattice. Secondly, a crystal must be formed, and this can usually be done at various densities. Thirdly, the crystals in a colliding-beam machine are brought into collision. We study all of these processes using the molecular dynamics (MD) method. The work parallels what was done previously, but the new part is to study the crystal-crystal interaction in collision. We initially study the zero-temperature situation. If the beam-beam force (or equivalent tune shift) is too large then overlapping crystals can not be created (rather two spatially separated crystals are formed). However, if the beam-beam force is less than but comparable to that of the space-charge forces between the particles, we find that overlapping crystals can be formed and the beam-beam tune shift can be of the order of unity. Operating at low but non-zero temperature can increase the luminosity by several orders of …