This paper will describe simulating metallic grain growth using the Gradient Weighted Moving Finite Elements code, GRAIN3D. The authors also describe the set of mesh topology change operations developed to respond to changes in the physical topology such as the collapse of grains and to maintain uniform calculational mesh quality. Validation of the method is demonstrated by comparison to analytic calculations. The authors present results of multigrain simulations where grain boundaries evolve by mean curvature motion and include results which incorporate grain boundary orientation dependence.

The recent development of miniature inductive adders has made it feasible to design programmable, high-repetition-rate pulsers with a substantially higher voltage than is possible using a conventional field-effect transistor architecture. Prototype pulsers using the new technology are being developed as part of a series of experiments at LLNL to test the concept of a recirculating induction accelerator. Preliminary numerical work is reported here to determine what effects the higher-voltage pulsers would have on the beam quality of the LLNL small recirculator.

A key component of the DIII-D tokamak fusion experiment is a flexible and easy to expand digital control system which actively controls a large number of parameters in real-time. These include plasma shape, position, density, and total stored energy. This system, known as the PCS (plasma control system), also has the ability to directly control auxiliary plasma heating systems, such as the 20 MW of neutral beams routinely used on DIII-D. This paper describes the implementation of a real-time algorithm allowing substitution of power from one neutral beam for another, given a fault in the originally scheduled beam. Previously, in the event of a fault in one of the neutral beams, the actual power profile for the shot might be deficient, resulting in a less useful or wasted shot. Using this new real-time algorithm, a stand by neutral beam may substitute within milliseconds for one which has faulted. Since single shots can have substantial value, this is an important advance to DIII-D`s capabilities and utilization. Detailed results are presented, along with a description not only of the algorithm but of the simulation setup required to prove the algorithm without the costs normally associated with using physics operations time.

We report on the processing optimization and fabrication of ramp-edge high-temperature superconducting junctions by using alternative materials for both superconductor electrodes and normal-metal barrier. By using Ag-doped YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} (Ag:YBCO) as electrodes and a cation-modified compound of (Pr{sub y}Gd{sub 0.6{minus}y})Ca{sub 0.4}Ba{sub 1.6}La{sub 0.4}Cu{sub 3}O{sub 7} (y = 0.4, 0.5, and 0.6) as a normal-metal barrier, high-temperature superconducting Josephson junctions have been fabricated in a ramp-edge superconductor/normal-metal/superconductor (SNS) configuration. By using Ag:YBCO as electrodes, we have found that the processing controllability /reproducibility and the stability of the SNS junctions are improved substantially. The junctions fabricated with these alternative materials show well-defined RSJ-like current vs voltage characteristics at liquid nitrogen temperature.

Improved methods for the determination of carbon tetrachloride are described. These methods incorporate purge-and-trap concentration of heated dry samples, an improved methanol extraction procedure, and headspace sampling. The methods minimize sample pretreatment, accomplish solvent substitution, and save time. The methanol extraction and headspace sampling procedures improved the method detection limits and yielded better sensitivity, good recoveries, and good performance. Optimization parameters are shown. Results obtained with these techniques are compared for soil samples from contaminated sites.

The privatization efforts at the U.S. Department of Energy's Hanford Nuclear Reservation have been very successful primarily due to a disciplined process for project selection and execution. Early in the development of Privatization at Hanford, the Department of Energy determined that a disciplined alternatives generation and analysis (AGA) process would furnish the candidate projects with the best probability for success. Many factors had to be considered in the selection of projects. Westinghouse Hanford Company was assigned to develop this process and facilitate the selection of the first round of candidate privatization projects. Team members for the AGA process were assembled from all concerned organizations and skill groups. Among the selection criteria were legal, financial and technical considerations which had to be weighed.

The privatization efforts at the U.S. Department of Energy's Hanford Nuclear Reservation have been very successful primarily due to a disciplined process for project selection and execution. Early in the development of Privatization at Hanford, the Department of Energy determined that a disciplined alternatives generation and analysis (AGA) process would furnish the candidate projects with the best probability for success. Many factors had to be considered in the selection of projects. Westinghouse Hanford Company was assigned to develop this process and facilitate the selection of the first round of candidate privatization projects. Team members for the AGA process were assembled from all concerned organizations and skill groups. Among the selection criteria were legal, financial and technical considerations which had to be weighed.

Many portable fuel cell applications require high pressure hydrogen, oxygen, or both. High pressure PEM systems that were originally designed and developed primarily for aerospace applications are being redesigned for use in portable applications. Historically, applications can be broken into weight sensitive and weight insensitive cell stack designs. Variants of the weight sensitive designs have been considered to refill oxygen bottles for space suits, to provide oxygen for space shuttle, to provide oxygen and/or reboost propellants to the space station, and to recharge oxygen bottles for commercial aviation. A long operating history has been generated for weight insensitive designs that serve as oxygen generators for submarines. Exciting future vehicle concepts and portable applications are enabled by carefully designing lightweight stacks which do not require additional pressure containment. These include high altitude long endurance solar rechargeable aircraft and airships, water refuelable spacecraft, and a variety of field portable systems. High pressure electrolyzers can refill compressed hydrogen storage tanks for fuel cell powered vehicles or portable fuel cells. Hamilton Standard has demonstrated many high pressure PEM water electrolyzer designs for a variety of applications. Electrolyzers with operational pressures up to 3000 psi (20.7 MPa) are currently used for US Navy submarine oxygen …

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COG is a major multiparticle simulation code in the LLNL Monte Carlo radiation transport toolkit. It was designed to solve deep-penetration radiation shielding problems in arbitrarily complex 3D geometries, involving coupled transport of photons, neutrons, and electrons. COG was written to provide as much accuracy as the underlying cross-sections will allow, and has a number of variance-reduction features to speed computations. Recently COG has been applied to the simulation of high- resolution radiographs of complex objects and the evaluation of contraband detection schemes. In this paper we will give a brief description of the capabilities of the COG transport code and show several examples of neutron and gamma-ray imaging simulations. Keywords: Monte Carlo, radiation transport, simulated radiography, nonintrusive inspection, neutron imaging.

A major obstacle for the broad application of cathodic arc plasma deposition is the presence of micro- and nanoparticles in the plasma, also often referred to as 'macroparticles'. This paper reviews the formation of macroparticles at cathode spots, their interaction with the arc plasma and substrate, and macroparticle separation and removal from the plasma by various filtering methods. Nineteen variants of filters are discussed, including Aksenov's classic 90{sup o}-duct filter, filters of open architecture, and the concept of stroboscopic filtering.

The DOE Accelerated Strategic Computing Initiative (ASCI) is an applications-driven program requiring use of scalable, high-performance architectures to meet aggressive engineering needs related to safety of the Nation`s nuclear stockpile. ASCI will accelerate development of computational methods and tools for predictive simulation and for virtual prototyping needed to re-certify the existing stockpile, assess the effects of component aging, and to evaluate accident scenarios. The purpose of this paper is to summarize recent performance results from an important ASCI-related application and to speculate on how trends within the computer industry and in computer architecture relate to these results.

This paper evaluates the strength of head on and parasitic beam-beam collisions in RHIC when the crossing angle is zero. A non-zero crossing angle is not required in normal operation with 120 bunches, thanks to the early separation of the two beams. The RHIC lattice is shown to easily accommodate even conservatively large crossing angles, for example in beam dynamics studies, or in future operational upgrades to as many as 360 bunches per ring. A modest loss in luminosity is incurred when gold ions collide at an angle after 10 hours of storage.

During the past several decades manganin gauges have been used extensively for making in-situ high pressure measurements in materials under dynamic loading conditions. Prior to their use manganin gauges were calibrated but only under normal ambient temperatures. Recent interest in the behavior of both reactive and inert materials, when they were subjected to dynamic loading while being at high initial temperature, required a re-visit of the calibration procedure and reconfirmation of the gauges' proper behavior in such an extreme thermal environment. The paper describes the procedure of making such new calibrations of the existing manganin gauges and reports on the new findings. The Hugoniot for 6061-T6 aluminum at 250*C is also given.

A new tool has been developed for calculating the capacitance matrix for complex 3D interconnect structures involving multiple layers of irregularly shaped interconnect, imbedded in different dielectric materials. This method utilizes a new 3D adaptive unstructured grid capability, and a linear finite element algorithm. The capacitance is determined from the minimum in the total system energy as the nodes are varied to minimize the error in the electric field in the dielectric(s).

The use of vegetation analyses to outline areas of near-surface enrichment with metals and organic compounds was pioneered by the mining and petroleum industries. Research and development (R&D) on environmental applications is focusing on the ability of vegetation to remediate soils. Certain contaminants are taken up by plants and either stored in the plant tissue for easy harvesting and removal or changed into products that are not a health concern. In the development of its Expedited Site Characterization (ESC) methodology, our group at Argonne has focused its R&D on the application of vegetation analyses to detect subsurface contamination in vadose zone soils. We have developed the technology to locate past spills or leaks of carbon tetrachloride that penetrated the vadose zone and contaminated underlying drinking water supplies. Vegetation analysis is attractive as a first-step exploratory technique because it is noninvasive, rapid, and inexpensive. The technique requires collection of a uniform, constant sample and an analytical method with a low detection limit and high-quality results.

Previous Technical Safety Requirements (TSRs) established to support plutonium production activities at the Rocky Flats Environmental Technology Site (RFETS) were heavily focused on engineered safety features that would mitigate potential accidents. With the change in mission in 1992 to Site closure, and considering antiquated equipment nearing the end of their useful life, a change in philosophy was adopted to emphasize preventive controls that are mostly administrative. The new Administrative Controls (ACs) developed in the last few years include discrete attributes of safety management programs (SMPs) that are specifically credited to prevent or mitigate an accident, and include requirements on handling individual deviations, programmatic deficiencies, and TSR AC violations. The primary benefit of these changes is fewer requirements on equipment that allow the contractor more flexibility to maintain the defense-in-depth safety systems in a more cost-effective manner. A disadvantage of these new ACs is that implementation has become cumbersome and difficult to manage, e.g., resulted in an increased burden of demonstrating compliance and required an additional infrastructure to track deviations and deficiencies. In order to improve the efficiency of the authorization basis (AB) process to support accelerated Site closure according to the 2006 Plan, the Site has recently modified the ABs …

Future nuclear fuel must satisfy three sets of requirements: longer times between refueling; concerns for weapons proliferation; and development of a spent fuel form more suitable for direct geologic disposal. This project has investigated a fuel consisting of mixed thorium and uranium dioxide to satisfy these requirements. Results using the SCALE 4.3 code system indicated that the mixed Th-U fuel could be burned to 72 MWD/kg or 100 MWD/kg using 25% and 35% UO2 respectively. The uranium remained below 20 % total fissile fraction throughout the cycle, making it unusable for weapons. Total plutonium production per MWD was a factor of 4.5 less in the Th-U fuel than in the conventional fuel; Pu-239 production per MWD was a factor of 6.5 less; and the plutonium produced was high in Pu-238, leading to a decay heat 5 times greater than that from plutonium derived from conventional fuel and 40 times greater than weapons grade plutonium. High decay heat would require active cooling of any crude weapon, lest the components surrounding the plutonium be melted. Spontaneous neutron production for plutonium from Th-U fuel was 2.3 times greater than that from conventional fuel and 15 times greater than that from weapons grade plutonium. …

Future nuclear fuels must satisfy three sets of requirements: longer times between refueling; concerns for weapons proliferation; and development of a spent fuel form more suitable for direct geologic disposal. This project has investigated a fuel consisting of mixed thorium and uranium dioxide to satisfy these requirements. Results using the SCALE 4.3 code system indicated that the mixed Th-U fuel could be burned to 72 MWD/kg or 100 MWD/kg using 25% of 35% UO2 respectively. The uranium remained below 20% total fissile fraction throughout the cycle, making it unusable for weapons. Total plutonium production per MWD was a factor of 4.5 less in the Th-U fuel than in the conventional fuel; Pu-239 production per MWD was a factor of 6.5 less; and the plutonium produced was high in Pu-238, leading to a decay heat 5 times greater than that from plutonium derived from conventional fuel and 40 times greater than weapons grade plutonium. High decay heat would require active cooling of any crude weapon, lest the components surrounding the plutonium be melted. Spontaneous neutron production for plutonium from Th-U fuel was 2.3 times greater than that from conventional fuel and 15 times greater than that from weapons grade plutonium. High …

This paper describes the first efforts at developing a set of prototypical buildings defined to capture the key features affecting airflow and pollutant transport in buildings. These buildings will be used to model airflow and pollutant transport for emergency response scenarios when limited site-specific information is available and immediate decisions must be made, and to better understand key features of buildings controlling occupant exposures to indoor pollutant sources. This paper presents an example of this approach for a prototypical intermediate-sized, open style, commercial building. Interzonal transport due to a short-term source release, e.g., accidental chemical spill, in the bottom and the upper floors is predicted and corresponding HVAC system operation effects and potential responses are considered. Three-hour average exposure estimates are used to compare effects of source location and HVAC operation.

The CEBAF Large Acceptance Spectrometer (CLAS) has been operating for nuclear physics experiments since December 1997. A description of its individual components and their specifications is given, followed by a description of the overall spectrometer performance and a summary of the types of physics data which have been taken to date.

The most ambitious implementation of the Jefferson Lab data acquisition system (CODA) to date is for the CLAS spectrometer in Experimental Hall B. CLAS has over 40,000 instrumented channels and uses up to 30 front-end (FASTBUS/VME) crates in the DAQ subsystem. During the initial experiments the authors found that performance of the fully instrumented DAQ system did not scale as expected based on single point to point benchmarks. Over the past year the authors have been able to study various performance bottlenecks in the CLAS DAQ system including front-end real time performance, switched 100BaseT Ethernet data transport, and online data distribution and recording. Performance tuning was necessary for components on both real time (VxWorks) and UNIX (Solaris) operating systems. In addition, a new efficient Event Transfer System (ET) was developed to provide faster online monitoring while having minimal impact on data throughput to storage. They discuss these issues and efforts to overcome the real world problems associated with running a high performance DAQ system on a variety of commercial hardware and software.

In order to gain a risk management perspective, the DOE Rocky Flats Field Office (RFFO) initiated a survey of other DOE sites regarding risks from potential accidents associated with transuranic (TRU) storage and/or processing facilities. Recently-approved authorization basis documents at the Rocky Flats Environmental Technology Site (RFETS) have been based on the DOE Standard 3011 risk assessment methodology with three qualitative estimates of frequency of occurrence and quantitative estimates of radiological consequences to the collocated worker and the public binned into three severity levels. Risk Class 1 and 2 events after application of controls to prevent or mitigate the accident are designated as risk-dominant scenarios. Accident Evaluation Guidelines for selection of Technical Safety Requirements (TSRs) are based on the frequency and consequence bin assignments to identify controls that can be credited to reduce risk to Risk Class 3 or 4, or that are credited for Risk Class 1 and 2 scenarios that cannot be further reduced. This methodology resulted in several risk-dominant scenarios for either the collocated worker or the public that warranted consideration on whether additional controls should be implemented. RFFO requested the survey because of these high estimates of risks that are primarily due to design characteristics of …

An experiment to study sawtooth phenomena and to find the threshold for sawtooth stabilization with neutral beam injection heating, as was commonly observed on TFTR, has been done on DIII-D. In the experiments, with co-tangential neutral beam injection at powers of up to 13MW, the sawtooth period was observed to increase to of order 250 msec. Stabilization of the sawteeth for the length of the high power NBI (0.5-0.8 sec) was not observed. The sawtooth characteristics were studied with fast electron temperature (ECE) and soft x-ray diagnostics. Fast, 2 msec interval, measurements were made of the ion temperature evolution following the sawtooth to document the ion heat pulse characteristics. These data show that the ion heat pulse does not exhibit the very fast, ''ballistic'' behavior seen for the electrons. The current profile and other equilibrium profiles were measured on slower time scales. These results are compared to the data from similar studies carried out on TFTR.