We have estimated interference from external background radiation for a computed tomography (CT) scanner. Our intention is to estimate the interference that would be expected for the high-resolution SkyScan 1072 desk-top x-ray microtomography system. The SkyScan system uses a Microfocus x-ray source capable of a 10-{micro}m focal spot at a maximum current of 0.1 mA and a maximum energy of 130 kVp. All predictions made in this report assume using the x-ray source at the smallest spot size, maximum energy, and operating at the maximum current. Some of the systems basic geometry that is used for these estimates are: (1) Source-to-detector distance: 250 mm, (2) Minimum object-to-detector distance: 40 mm, and (3) Maximum object-to-detector distance: 230 mm. This is a first-order, rough estimate of the quantity of interference expected at the system detector caused by background radiation. The amount of interference is expressed by using the ratio of exposure expected at the detector of the CT system. The exposure values for the SkyScan system are determined by scaling the measured values of an x-ray source and the background radiation adjusting for the difference in source-to-detector distance and current. The x-ray source that was used for these measurements was not the …

Efforts to more effectively monitor nuclear explosions include the calibration of travel times along specific paths. Benchmark events are used to improve travel-time prediction by (1) improving models, (2) determining travel times empirically, or (3) using a hybrid approach. Even velocity models that are determined using geophysical analogy (i.e. models determined without the direct use of calibration data) require validation with calibration events. Ideally, the locations and origin times of calibration events would be perfectly known. However, the existing set of perfectly known events is spatially limited and many of these events occurred prior to the installation of current monitoring stations, thus limiting their usefulness. There are, however, large numbers of well (but not perfectly) located events that are spatially distributed, and many of these events may be used for calibration. Identifying the utility and limitations of the spatially distributed set of imperfect calibration data is of paramount importance to the calibration effort. In order to develop guidelines for calibration utility, we examine the uncertainty and correlation of location parameters under several network configurations that are commonly used to produce calibration-grade locations. We then map these calibration uncertainties through location procedures with network configurations that are likely in monitoring situations. …

Recent work in heavy-ion fusion accelerators and final focusing systems shows a trend towards less current per beam, and thus, a greater number of beams. Final focusing magnets are susceptible to nuclear heating, radiation damage, and neutron activation. The trend towards more beams, however, means that there can be less shielding for each magnet, Excessive levels of nuclear heating may lead to magnet quench or an intolerable recirculating power for magnet cooling. High levels of radiation damage may result in short magnet lifetimes and low reliability. Finally, neutron activation of the magnet components may lead to difficulties in maintenance, recycling, and waste disposal. The present work expands upon previous, three-dimensional magnet shielding calculations for a modified version of the HYLIFE-I1 IFE power plant design. We present key magnet results as a function of the number of beams.

A broad baseline study of the levels and distributions of trace metals and PCB compounds in sediments has been undertaken. PCB concentrations in surface sediments reflect the source of these contaminates in the region. The highest PCB concentrations as Aroclor 1260 (approximately 10 ng g{sup -1}) were found in sediments near the outflow of the Po river. The lowest concentrations (1.5 ng g{sup -1} dry) were associated with the sediments from the Jabuka Pit in the Middle Adriatic. These values are quite similar to total PCBs (<1.0-17) measured in surface sediments sampled off the coast of Croatia in 1977-78. Thus, based on the limited amount of new data available, it appears that there has been little, if any, decrease in PCB loading in Adriatic sediments over the past 15 years. Downcore profiles of PCBs in sediment cores are also discussed from a pollution history standpoint. Likewise, total mercury in surface sediments was also highest at stations off the Po (403-499 ng g{sup -1} dry) and lowest (67-224 ng g{sup -1}) in the Jabuka Pit. In one core located just south of the Po outflow, total Hg concentrations at all depths were relatively high decreasing gradually from approximately 400 ng g{sup …

Wavefront reconstruction techniques using the least-squares estimators are computationally quite expensive. We compare wavelet and Fourier transforms techniques in addressing the computation issues of wavefront reconstruction in adaptive optics. It is shown that because the Fourier approach is not simply a numerical approximation technique unlike the wavelet method, the Fourier approach might have advantages in terms of numerical accuracy. However, strictly from a numerical computations viewpoint, the wavelet approximation method might have advantage in terms of speed. To optimize the wavelet method, a statistical study might be necessary to use the best basis functions or ''approximation tree.''

This newsletter is prepared for the NARUC Subcommittee on Renewable Energy to promote information sharing on state-level renewable electric activities. It is sponsored by the Office of Power Technologies of the U.S. Department of Energy.

As a result of nuclear weapons testing and accidents, plutonium has been distributed into the environment. The areas close to the sites of these tests and accidental dispersions contain plutonium deposition of such a magnitude that health authorities and responsible officials have mandated that the contaminated areas be protected, generally through isolation or removal of the contaminated areas. In recent years remedial actions have taken place at all these sites. For reasons not entirely clear, the public perceives radiation exposure risk to be much greater than the evidence would suggest [1]. This perception seems to be particularly true for plutonium, which has often been ''demonized'' in various publications as the ''most hazardous substance known to man'' [2]. As the position statement adapted by the Health Physics Society explains, ''Plutonium's demonization is an example of how the public has been misled about radiation's environmental and health threats generally, and in cases like plutonium, how it has developed a warped ''risk perception'' that does not reflect reality'' [3]. As a result of this risk perception and ongoing debate surrounding environmental plutonium contamination, remedial action criteria are difficult to establish. By examining the data available before and after remedial actions taken at the …

Our work under this support broadly falls into five categories: automatic differentiation, sparsity, constraints, parallel computation, and applications. Automatic Differentiation (AD): We developed strong practical methods for computing sparse Jacobian and Hessian matrices which arise frequently in large scale optimization problems [10,35]. In addition, we developed a novel view of "structure" in applied problems along with AD techniques that allowed for the efficient application of sparse AD techniques to dense, but structured, problems. Our AD work included development of freely available MATLAB AD software. Sparsity: We developed new effective and practical techniques for exploiting sparsity when solving a variety of optimization problems. These problems include: bound constrained problems, robust regression problems, the null space problem, and sparse orthogonal factorization. Our sparsity work included development of freely available and published software [38,39]. Constraints: Effectively handling constraints in large scale optimization remains a challenge. We developed a number of new approaches to constrained problems with emphasis on trust region methodologies. Parallel Computation: Our work included the development of specifically parallel techniques for the linear algebra tasks underpinning optimization algorithms. Our work contributed to the nonlinear least-squares problem, nonlinear equations, triangular systems, orthogonalization, and linear programming. Applications: Our optimization work is broadly applicable …

Pacific Northwest National Laboratory was awarded ten Environmental Management Science Program (EMSP) research grants in fiscal year 1996, six in fiscal year 1997, eight in fiscal year 1998 and seven in fiscal year 1999.(a) All of the fiscal year 1996 awards have been completed and the Principal Investigators are writing final reports, so their summaries will not be included in this document. This section summarizes how each of the currently funded grants addresses significant U.S. Department of Energy (DOE) cleanup issues, including those at the Hanford Site. The technical progress made to date in each of these research projects is addressed in more detail in the individual progress reports contained in this document. This research performed at PNNL is focused primarily in four areas: Tank Waste Remediation, Decontamination and Decommissioning, Spent Nuclear Fuel and Nuclear Materials, and Soil and Groundwater Cleanup.

Magnetic resonance is the most powerful analytical tool used by chemists today. Its applications range from determining structures of large biomolecules to imaging of human brains. Nevertheless, magnetic resonance remains a relatively young field, in which many techniques are currently being developed that have broad applications. In this dissertation, two new techniques are presented, one that enables the determination of torsion angles in solid-state peptides and proteins, and another that involves imaging of heterogenous materials at ultra-low magnetic fields. In addition, structural studies of the prion protein via solid-state NMR are described. More specifically, work is presented in which the dependence of chemical shifts on local molecular structure is used to predict chemical shift tensors in solid-state peptides with theoretical ab initio surfaces. These predictions are then used to determine the backbone dihedral angles in peptides. This method utilizes the theoretical chemicalshift tensors and experimentally determined chemical-shift anisotropies (CSAs) to predict the backbone and side chain torsion angles in alanine, leucine, and valine residues. Additionally, structural studies of prion protein fragments are described in which conformationally-dependent chemical-shift measurements were made to gain insight into the structural differences between the various conformational states of the prion protein. These studies are of …

In 1999, eight soil gas sampling points ranging in depth from 4.9 ft to 32 ft below ground surface (bgs) in two clusters were installed adjacent to well 699-41-1, south of the Hanford Townsite. Fifteen soil gas sampling points, ranging in depth from 7.0 ft to 10.4 ft bgs, were installed to the north and east of the 100-K East Reactor facility. Gas phase soil moisture samples were collected using silica gel traps from all eight sampling locations adjacent to well 699-41-1 and eight locations at the 100-K Area. Soil gas samples for helium-3 measurements were collected at all sampling points. No detectable tritium (<240 pCi/L) was found in the soil moisture samples from either the Hanford Townsite or 100-K Area sampling points. This behavior suggests that tritiated moisture from groundwater is not migrating upward to the sampling points and there are no large vadose zone sources of tritium at either location. Helium-3 analyses of the soil gas samples showed significant enrichments relative to ambient air helium-3 concentrations with a depth dependence consistent with a groundwater source from decay of tritium. Helium-3/helium-4 ratios (normalized to the abundances in ambient air) at the Hanford Townsite ranged from 1.012 at 5 feet …

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The last major development effort for nuclear power and propulsion systems ended in 1993. Currently, there is not an initiative at either the National Aeronautical and Space Administration (NASA) or the U.S. Department of Energy (DOE) that requires the development of new nuclear power and propulsion systems. Studies continue to show nuclear technology as a strong technical candidate to lead the way toward human exploration of adjacent planets or provide power for deep space missions, particularly a 15,000 lbf bimodal nuclear system with 115 kW power capability. The development of nuclear technology for space applications would require technology development in some areas and a major flight qualification program. The last major ground test facility considered for nuclear propulsion qualification was the U.S. Air Force/DOE Space Nuclear Thermal Propulsion Project. Seven years have passed since that effort, and the questions remain the same, how to qualify nuclear power and propulsion systems for future space flight. It can be reasonable assumed that much of the nuclear testing required to qualify a nuclear system for space application will be performed at DOE facilities as demonstrated by the Nuclear Rocket Engine Reactor Experiment (NERVA) and Space Nuclear Thermal Propulsion (SNTP) programs. The nuclear infrastructure …

The US Department of Energy (DOE) Idaho National Engineering and Environmental Laboratory (INEEL) has embraced mobile wireless technology to help the disposition of hazardous and mixed radiological waste. The following paper describes one application the INEEL developed to increase the data accuracy and near-real time reporting requirements for waste management. With the continuous operational demands at the "site", it was difficult to sustain an accurate, up-to-date database required for regulatory compliance audits and reporting. Incorporating wireless mobile technology, the INEEL was able to increase the accuracy while reducing the data delay times previously encountered. Installation issues prolonged the project along with obstacles encountered with operations personnel. However, the success of this project was found in persistence and management support as well as the technology itself. Future wireless, mobile computing will continue at the INEEL for years to come based on a successful project that was able to integrate new technology to an existing waste management system with proven, increased data accuracy.

Utility partnership upgrades energy system to help meet the General Services Administration's (GSA) energy-saving goals.

The purpose of this report is to document the development of a radial grid that is suitable for evaluating the pathways and potential impacts of a release of radioactive materials to the environment within a distance of 84 kilometers.

This project is developing a fundamental conceptual design for a gas-cooled, modular, pebble bed reactor. Key technology areas associated with this design are being investigated which intend to address issues concerning fuel performance, safety, core neutronics and proliferation resistance, economics and waste disposal. Research has been initiated in the following areas: · Improved fuel particle performance · Reactor physics · Economics · Proliferation resistance · Power conversion system modeling · Safety analysis · Regulatory and licensing strategy Recent accomplishments include: · Developed four conceptual models for fuel particle failures that are currently being evaluated by a series of ABAQUS analyses. Analytical fits to the results are being performed over a range of important parameters using statistical/factorial tools. The fits will be used in a Monte Carlo fuel performance code, which is under development. · A fracture mechanics approach has been used to develop a failure probability model for the fuel particle, which has resulted in significant improvement over earlier models. · Investigation of fuel particle physio-chemical behavior has been initiated which includes the development of a fission gas release model, particle temperature distributions, internal particle pressure, migration of fission products, and chemical attack of fuel particle layers. · A balance …

The Department of Energy (DOE) created the National Transportation Program (NTP) whose goal is to ensure the availability of safe, efficient, and timely transportation of DOE materials. The Integration and Planning Group of the NTP, assisted by Global Technologies Incorporated (GTI), was tasked to identify requirements associated with the transport of DOE Environmental Management (EM) radiological waste/material. A systems engineering approach was used to identify source documents, extract requirements, perform a functional analysis, and set up a transportation requirements management database in RDD-100. Functions and requirements for transporting the following DOE radioactive waste/material are contained in the database: high level radioactive waste (HLW), low-level radioactive waste (LLW), mixed low-level radioactive waste (MLLW), nuclear materials (NM), spent nuclear fuel (SNF), and transuranic waste (TRU waste). The requirements will be used in the development of standard transportation protocols for DOE shipping. The protocols will then be combined into a DOE Transportation Program Management Guide, which will be used to standardize DOE transportation processes.

Utility partnership upgrades energy system to help meet the General Services Administration's (GSA) energy-saving goals.

The data evaluated in this qualification report have been cited in analysis and model reports (AMRs) in support of the Site Recommendation in determining the suitability of the Yucca Mountain Site for a repository for high level nuclear waste. The AMRs use these hydrochemical data as a basis for modeling the chemical interactions between groundwater and engineered materials, including waste forms, packages and materials in the engineered barrier system J-13 water is also used as a reactant in experiments performed to collect data on corrosion of waste packages and repository materials, on solubility of radionuclides, on waste form leach rates, and in simulations of the mobility of radionuclides in groundwater, among other applications. J-13 water serves effectively as a reference or surrogate water composition across the program. Establishing a qualified data set describing the composition of J-13 will help ensure commonality among the various studies.

A major concern often arising in structural integrity predictions is the possibility that low-energy brittle fracture could result as a consequence of cleavage either under normal operating or design accident conditions. This can be especially troublesome when the leak-before-break (LBB) approach shows an additional safety margin of the design. For LBB to be applicable, the fracture process must remain ductile (dimple rupture), and not change to cleavage. The American Society for Mechanical Engineers Boiler and Pressure Vessel Code (Code) provides guidelines for avoiding cleavage fracture for Code-accepted materials. Experimental results for a non-Code steel are provided, and show that cleavage may occur for a thickness under16 mm (where the code suggests it will not) after stable crack growth (&#8710;a) of up to 20 mm. This work is still in progress; test results are provided along with possible reasons for the mode transition, but complete explanations are still being developed.

Two computer modules are being constructed to model a new process for syngas upgrading and purification. The first module simulates the physical processes occurring in a fluid bed reactor where both gas and solid compositions and flow rates vary significantly along the axis of the reactor. The second module simulates the chemistry and mass transfer between the gas and solid phases. Primitive forms of the two modules have been developed and exercised over a range of performance parameters. These early tests verify that the modules will need to be expanded to model the reactors as series of individual zones in order to attain satisfactory predictive performance.

Utility partnership upgrades energy system to help meet the General Services Administration's (GSA) energy-saving goals

This calculation produces standard statistical data on the consumption of locally produced food and tap water. The results of this calculation provide input parameters for the GENII-S (Leigh et al. 1993) computer code to support calculation of Biosphere Dose Conversion Factors (BDCF) for the nominal performance (groundwater contamination) scenario and the volcanic eruption (contamination of soil by volcanic ash deposition) scenario. The requirement and parameters for these data are identified in ''Identification Of The Critical Group (Consumption Of Locally Produced Food And Tap Water)'' (CRWMS M&amp;O 2000a). This calculation is performed in accordance with the ''Development Plan for Calculation: Values and Consumption Rates of Locally Produced Food and Tap Water for the Receptor of Interest'' (CRWMS M&amp;O 2000b).