The long-term behavior of nuclear waste glass in a geologic repository may require a technical consideration of the role of colloids in the release and transport of radionuclides. The neglect of colloidal properties in assessing the near- and far-field migration behavior of actinides may lead to significant underestimates and poor predictions of biosphere exposure from high-level waste (HLW) disposal. Existing data on colloid-facilitated transport suggests that radionuclide migration may be enhanced, but the importance of colloids is not adequately assessed. Indeed, the occurrence of radionuclide transport, attributed to colloidal species, has been reported at Mortandad Canyon, Los Alamos and at the Nevada Test Site; both unsaturated regions are similar to the proposed HLW repository at Yucca Mountain. Although some developments have been made on understanding the transport characteristics of colloids, the characterization of colloids generated from the corrosion of the waste form has been limited. Colloids are known to incorporate radionuclides either from hydrolysis of dissolved species (real colloids) or from adsorption of dissolved species onto existing groundwater colloids (pseudocolloids); however, these colloids may be considered secondary and solubility limited when compared to the colloids generated during glass alteration.

This investigation addresses the combustion-related aspects of the reapplication of energetic materials as fuels in boilers as an economically viable and environmentally acceptable use of excess energetic materials. The economics of this approach indicate that the revenues from power generation and chemical recovery approximately equal the costs of boiler modification and changes in operation. The primary tradeoff is the cost of desensitizing the fuels against the cost of open burn/open detonation (OB/OD) or other disposal techniques. Two principal combustion-related obstacles to the use of energetic-material-derived fuels are NO{sub x} generation and the behavior of metals. NO{sub x} measurements obtained in this investigation indicate that the nitrated components (nitrocellulose, nitroglycerin, etc.) of energetic materials decompose with NO{sub x} as the primary product. This can lead to high uncontrolled NO{sub x} levels (as high as 2,600 ppm on a 3% O{sub 2} basis for a 5% blend of energetic material in the fuel). NO{sub x} levels are sensitive to local stoichiometry and temperature. The observed trends resemble those common during the combustion of other nitrogen-containing fuels. Implications for NO{sub x} control strategies are discussed. The behavior of inorganic components in energetic materials tested in this investigation could lead to boiler maintenance problems …

Fe/KClO{sub 4} pyrotechnic mixtures are used in thermal batteries to provide the heat necessary to bring the battery stack to operating temperatures of 550 to 600 C. This heat source is normally used as discs pressed from bulk powder. To evaluate the consequences associated with unexpected ignition of large amounts of heat powder, combustion of 84% Fe/16% KClO{sub 4} heat powders was conducted for various scenarios under controlled conditions and the response documented. Increasing amounts of heat powder--up to 8 lbs--were ignited in both unconfined and confined (sealed) containers in a remote area. The containers were thermocoupled and the resulting burning filmed with a standard video camera, high-speed (1,000 frames/s) film and video cameras, and an infrared video camera. A 20- minute video of the burning under the various conditions is presented.

This document for the final remedial action plan and site design has been prepared for US Department of Energy Environmental Restoration Division as part of the Uranium Mill Tailings Remedial Action plan. Comments and responses are included for the site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado.

This paper discusses information systems for building life-cycle performance analysis and the use of computer-based commissioning tools within this context. There are many reasons why buildings do not perform in practice as well as intended at the design stage. One reason is the lack of commissioning. A second reason is that design intent is not well documented, and performance targets for building components and systems are not well specified. Thus, criteria for defining verification and functional tests is unclear. A third reason is that critical information is often lost throughout the building life-cycle, which causes problems such as misunderstanding of operational characteristics and sequences and reduced overall performance. The life-cycle building performance analysis tools project discussed in this paper are focused on chillers and cooling systems.

Workforce planning has become an increasing concern within the DOE community as the Office of Environmental Restoration and Waste Management (ER/WM or EM) seeks to consolidate and refocus its activities and the Office of Defense Programs (DP) closes production sites. Attempts to manage the growth and skills mix of the EM workforce while retaining the critical skills of the DP workforce have been difficult due to the lack of a consistent set of occupational titles and definitions across the complex. Two reasons for this difficulty may be cited. First, classification systems commonly used in industry often fail to cover in sufficient depth the unique demands of DOE`s nuclear energy and research community. Second, the government practice of contracting the operation of government facilities to the private sector has introduced numerous contractor-specific classification schemes to the DOE complex. As a result, sites/contractors report their workforce needs using unique classification systems. It becomes difficult, therefore, to roll these data up to the national level necessary to support strategic planning and analysis. The Common Occupational Classification System (COCS) is designed to overcome these workforce planning barriers. The COCS is based on earlier workforce planning activities and the input of technical, workforce planning, and …

Planar magnetron cathodes have arching magnetic field lines which concentrate plasma density near the electrode surface. This enhances the ion bombardment of the surface and the yield of sputtered atoms. Magnetron cathodes are used in the Plasma Electrode Pockels Cell (PEPC) devices of the Laser Program because they provide for significantly higher conduction than do glow discharges. An essential feature of magnetron cathodes is that the vector product of the perpendicular electric field, E[sub y], with the parallel component of the magnetic field, B[sub x], forms a closed track with a circulating current along the cathode surface. An analytical, 2D, two component, quasi-neutral, continuum model yields formulas for the plasma density, the total and component current densities, the electric field, and the positive electrical potential, between the cathode surface and a distant, uniform plasma. For a specific gas, the free parameters are electron temperature, gas number density, and total current. The model is applied to the interpretation of experimental data from the PEPC device, as well as a small vacuum facility for testing magnetron cathodes. Finally, the model has been applied to generate cross sectional views of a PEPC magnetron cathode track.

For fast, reliable determination of U and Pu concentrations in samples, ICP/AES (inductively coupled plasma/atomic emission spectrometry) and alpha counting can be used. Data show that ICP/AES or alpha counting can be used to obtain high-quality results for Pu determination. When high accuracy is needed for mass balance, however, MSID (mass spectrometric isotope dilution) is the better choice. Also, ICP/AES is a poor method to use for Pu determination, when samples contain large amounts of spectrally interfering elements, such as U, rare earths, and Zr. In these cases, if ICP/AES is used, chemical separation of Pu is needed prior to analysis, or the alpha counting method can be used. Because of the poor sensitivity for U in ICP/AES, use of MSID is the only practical method for samples low in uranium.

Tissue ablation with ultrashort laser pulses offers several unique advantages. The nonlinear energy deposition is insensitive to tissue type, allowing this tool to be used for soft and hard tissue ablation. The localized energy deposition lead to precise ablation depth and minimal collateral damage. This paper reports on efforts to study and demonstrate tissue ablation using an ultrashort pulse laser. Ablation efficiency and extent of collateral damage for 0.3 ps and 1000 ps duration laser pulses are compared. Temperature measurements of the rear surface of a tooth section is also presented.

A vegetation study at the Comanche Peak Steam Electric Station (CPSES) near Glen Rose, Texas was conducted in 1991 and 1992. The CPSES is a commercial nuclear power plant owned and operated by Texas Utilities Electric of Dallas, Texas. The US Nuclear Regulatory Commission (USNRC) requires the CPSES to routinely sample broadleaf vegetation in place of milk samples. Few commercial dairies exist in the vicinity. Broadleaf tree species are scarce because the climate and local limestone geology have produced a dry rolling hill topography. An evergreen juniper is the dominant tree species. Few broadleaves during the winter season have hindered year-round sampling. This study compares the environmental {sup 137}Cs concentrations between broadleaf and evergreen foliage at CPSES. Soil {sup 137}Cs concentrations from each vegetation location were also compared to the foliage {sup 137}Cs concentrations. The study`s objective was to determine if the deciduous and evergreen vegetation {sup 137}Cs concentrations are statistically the same.

The objective of this report is to evaluate the equivalency of two methods used to sample nonradioactive gases and vapors in the Hanford Site high-level waste tank headspaces. In addition to the comparison of the two sampling methods, the effects of an in-line fine particle filter on sampling results are also examined to determine whether results are adversely affected by its presence. This report discusses data from a January 1996 sampling.

The American Society for Testing and Materials (ASTM) has been working with the US Environmental Protection Agency (EPA) to develop methods for use in the Environmental RCRA/CERCLA program. Two standards being developed are guides to field compositing and laboratory subsampling. Correctly performed compositing and subsampling are critical in the chain of sampling and analytical events. They must be accomplished in compliance with project objectives and instructions to assure that the resulting data is representative. In a site characterization effort, the collection of composite samples may be used to estimate the mean concentration of a waste analyte in contaminated media. Other reasons to composite include reducing costs, efficiently determining the absence or possible presence of a hot spot, and, when coupled with retesting schemes, locating hot spots. If composite samples are collected, it is necessary to ensure that a representative sample is obtained for analysis. This may mean that samples must be mixed and subsampled using procedures that could include pan mixing and quartering, a mixing square, kneading, sieving and mixing, and particle size reduction. Field subsampling procedures include use of a rectangular scoop, an alternate scoop technique, and the slab-cake methods. A significant source of analytical error exists in obtaining …

Issues surrounding the use of ambient vibration modes for the location of structural damage via dynamically measured flexibility are examined. Several methods for obtaining the required mass- normalized dynamic mode shapes from ambient modal data are implemented and compared. The method are applied to data from a series of ambient modal tests on an actual highway bridge. Results indicate that for the damage case examined, the flexibility from the ambient mode shapes gave a better indication of damage than the flexibility from the forced-vibration mode shapes. This improved performance is attributed to the higher excitation load levels that occur during the ambient test.

The Multi-Mechanism Deformation (M-D) model for creep in rock salt has been used in three-dimensional computations for the Waste Isolation Pilot Plant (WIPP), a potential waste, repository. These computational studies are relied upon to make key predictions about long-term behavior of the repository. Recently, the M-D model was extended to include creep-induced damage. The extended model, the Multi-Mechanism Deformation Coupled Fracture (MDCF) model, is considerably more complicated than the M-D model and required a different technology from that of the M-D model for a computational implementation.

Computational modeling can play an important role both in designing laser-tissue interaction experiments and in understanding the underlying mechanisms. This can lead to more rapid and less expensive development if new procedures and instruments, and a better understanding of their operation. We have recently directed computer programs and associated expertise developed over many years to model high intensity laser-matter interactions for fusion research towards laser-tissue interaction problem. A program called LATIS is being developed to specifically treat laser-tissue interaction phenomena, such as highly scattering light transport, thermal coagulation, and hydrodynamic motion.

This paper makes an effort to project the theoretical lessons of the SEARCH (Search Envisioned As Relation and Class Hierarchizing) framework introduced elsewhere (Kargupta, 1995b) in the context of natural evolution and introduce the gene expression messy genetic algorithm (GEMGA) -- a new generation of messy GAs that directly search for relations among the members of the search space. The GEMGA is an O({vert_bar}{Lambda}{vert_bar}{sup k}({ell} + k)) sample complexity algorithm for the class of order-k delineable problems (Kargupta, 1995a) (problems that can be solved by considering no higher than order-k relations) in sequence representation of length {ell} and alphabet set {Lambda}. Unlike the traditional evolutionary search algorithms, the GEMGA emphasizes the computational role of gene expression and uses a transcription operator to detect appropriate relations. Theoretical conclusions are also substantiated by experimental results for large multimodal problems with bounded inappropriateness of representation.

A novel bench-top device for producing intense, fast pulses of x-rays has been designed with 10 ps fwhm (full-width at half-maximum) x-ray pulse width, 120 keV maximum energy, 100 kHz repetition rate, and 1 A peak current onto the x-ray anode. The device includes three sections: (1) an electron gun that generates 5 ns wide pulses of 120 keV electrons at 100 kHz; (2) solenoidal magnetic lenses and deflection plates that focus the electrons onto an aperture plate and sweep the pulsed beam past the aperture, respectively; and (3) a tungsten anode onto which the post-aperture electrons are focused, producing pulses of x-rays. At a sweeping rate of 10{sup 13} V/s, the electron pulses and resulting x-ray pulses are reduced to about 10 ps. The design process used EGUN (an electron optics and gun design program) electron trajectory simulations, including calculation of important space charge effects. When built, this instrument will be used to excite new, fast, bright scintillator samples in crystal or powdered form, allowing fluorescent lifetimes and spectra to be measured with a microchannel PMT. The very narrow 10 ps x-ray pulse width is necessary for accurate measurements of the risetimes of very fast scintillators (e.g., BaF{sub 2}). …

Paint stripping of the U.S. Air Force`s large transport aircrafts is currently a labor-intensive, manual process. Significant reductions in costs, personnel and turnaround time can be accomplished by the judicious use of automation in some process tasks. This paper presents the conceptual design of a coating removal systems for the tail surfaces of the C-5 plane. Emphasis is placed on the technology selection to optimize human-automation synergy with respect to overall costs, throughput, quality, safety, and reliability. Trade- offs between field-proven vs. research-requiring technologies, and between expected gain vs. cost and complexity, have led to a conceptual design which is semi-autonomous (relying on the human for task specification and disturbance handling) yet incorporates sensor- based automation (for sweep path generation and tracking, surface following, stripping quality control and tape/breach handling).

All valid constitutive equations must satisfy two general invariance principles as well several other principles. In this paper the MDCF (Multimechanism Deformation Coupled Fracture) model for rock salt is shown to be thermodynamically consistent, coordinate invariant, frame indifferent, and physically admissible. Additionally, the stress rates used in the formulation are shown to be kinematically consistent with the Cauchy stress rates.

Yucca Mountain Site Characterization Office of the US Department of Energy (DOE) is constructing an underground Exploratory Studies Facility (ESF), approximately 160 km (100 miles) northwest of Las Vegas, Nevada. This facility is being used to obtain geological, hydrological, geomechanical, thermomechanical and geochemical information to characterize, Yucca Mountain as a potential site to isolate High-Level Radioactive Waste from the accessible environment. The ESF, when completed, will consist of two ramps from surface (North and South ramp) to the potential repository horizon formations, a drift connecting the two ramps, test alcoves, and above and below ground operational support facilities. The ramps and connecting drift are being mined by a 7.62 m (25 ft) diameter, fully shielded, Tunnel Boring Machine (TBM). This paper describes the current status of the construction of the ESF and test alcoves. At the time of this writing, the following has been accomplished: North Ramp excavation is complete; four test alcoves have been excavated and are in use for scientific experiments; the excavation has reached the potential repository horizon; the drift connecting the two ramps is being excavated, and the excavation of a test alcove for thermal testing is in progress. The mining operations are ahead of schedule, …

To meet the environmental restoration and waste minimization goals of government and industry, several government laboratories, universities, and private companies have formed the Contaminant Analysis Automation (CAA) team. The goal of this consortium is to design and fabricate robotics systems that standardize and automate the hardware and software of the most common environmental chemical methods. In essence, the CAA team takes conventional, regulatory- approved (EPA Methods) chemical analysis processes and automates them. The automation consists of standard laboratory modules (SLMs) that perform the work in a much more efficient, accurate, and cost- effective manner.

We describe an iterative optimization algorithm developed for continuous contour phase plate design. With the help of this algorithm, a kinoform plate was designed to transform the square supergaussian beam into round supergaussian one. The phase function derived by the proposed method is smooth, has analytical representation, and has no singularities. Drawback is that this function does not provide smoothing of the incoming intensity distribution like random phase plates do and output intensity should be sensitive to variations of the illuminating light amplitude.

This report describes approaches to calculating and expressing radiation doses to the embryo/fetus from internal radionuclides. Information was obtained for selected, occupationally significant radioelements that provide a spectrum of metabolic and dosimetric characteristics. Evaluations are also presented for inhaled inert gases and for selected radiopharmaceuticals. Fractional placental transfer and/or ratios of concentration in the embryo/fetus to that in the woman were calculated for these materials. The ratios were integrated with data from biokinetic transfer models to estimate radioactivity levels in the embryo/fetus as a function of stage of pregnancy and time after entry into the transfer compartment or blood of the pregnant woman. These results are given as tables of deposition and retention in the embryo/fetus as a function of gestational age at exposure and elapsed time following exposure. Methodologies described by MIRD were extended to formalize and describe details for calculating radiation absorbed doses to the embryo/fetus. Calculations were performed using a model situation that assumed a single injection of 1 {mu}Ci into a woman`s blood; independent calculations were performed for administration at successive months of pregnancy. Gestational -stage-dependent dosimetric tabulations are given together with tables of correlations and relationships. Generalized surrogate dose factors and categorizations are provided in …

Conceptual designs of advanced combustion systems that utilize coal as a feedstock require high-temperature furnaces and heat transfer surfaces that can operate at temperatures much higher than those prevalent in current coal-fired power plants. The combination of elevated temperatures and hostile combustion environments necessitates development and application of advanced ceramic materials in these designs. The objectives of the present program are to evaluate (a) the chemistry of gaseous and condensed products that arise during combustion of coal; (b) the corrosion behavior of candidate materials in air, slag and salt environments for application in the combustion environments; and (c) the residual mechanical properties of the materials after corrosion. The program emphasizes temperatures in the range of 1000-1400{degrees}C for ceramic materials and 600-1000{degrees}C for metallic alloys. Coal/ash chemistries developed on the basis of thermodynamic/kinetic calculations, together with slags from actual combustors, are used in the program. The materials being evaluated include monolithic silicon carbide from several sources: silicon, nitride, silicon carbide in alumina composites, silicon carbide fibers in a silicon carbide- matrix composite, and some advanced nickel-base alloys. The paper presents results from an ongoing program on corrosion performance of candidate ceramic materials exposed to air, salt and slag environments and their …