The existing superconducting linac ATLAS is in many respects an ideal secondary beam accelerator for an ISOL (Isotope separator on-line) type radioactive beam facility. Such a facility would require the addition of two major accelerator elements: a low charge state injector for the existing heavy ion linac, and a primary beam accelerator providing 220 MV of acceleration for protons and light ions. Development work for both of these elements, including the option of superconducting cavities for the primary beam accelerator is discussed.

Lawrence Livermore National Laboratory is in the process of constructing the National Ignition Facility, a half million square foot facility which will house a 192 beam laser system capable of generating the 2 million joules of ultraviolet light energy necessary to achieve fusion ignition with inertial targets by 2004. More than 7,000 meter class optics will need to be manufactured by LLNL`s industrial partners to construct the laser system. The components will be manufactured starting in 1998 and will be finished by 2003. In 1994 it became clear through a series of funded cost studies that, in order to fabricate such an unprecedented number of large precision optics in so short a time for the lowest possible cost, new technologies would need to be developed and new factories constructed based on those technologies. At that time, LLNL embarked on an ambitious optics finishing technology development program costing more than $6M over 3 years to develop these technologies, working with three suppliers of large precision optics. While each development program centered upon the specialties and often proprietary technologies already existing in the suppliers facility, many of the technologies required for manufacturing large precision optics at the lowest cost possible are common …

DIAS, the Dynamic Information Architecture System, is an object-oriented simulation system that was designed to provide an integrating framework in which new or legacy software applications can operate in a context-driven frame of reference. DIAS provides a flexible and extensible mechanism to allow disparate, and mixed language, software applications to interoperate. DIAS captures the dynamic interplay between different processes or phenomena in the same frame of reference. Finally, DIAS accommodates a broad range of analysis contexts, with widely varying spatial and temporal resolutions and fidelity.

Experiments in a rapid compression machine have examined the influences of variations in pressure, temperature, and equivalence ratio on the autoignition of n-pentane. Equivalence ratios included values from 0.5 to � 2.0, compressed gas initial temperatures were varied between 675K and 980K, and compresed gas initial pressures varied from 8 to 20 bar. Numerical simulations of the same experiments were carried out using a detailed chemical kinetic reaction mechanism. The results are interpreted in terms of a low temperature oxidation mechanism involving addition of molecular oxygen to alkyl and hydroperoxyalkyl radicals. Idealized calculations are reported which identify the major reaction paths at each temperature. Results indicate that in most cases, the reactive gases experience a two-stage autoigni tion. The first stage follows a low temperature alkylperoxy radical isomerization pathway that is effectively quenched when the temperature reaches a level where dissociation reactions of alkylperoxy and hydroperoxyalkylperoxy radicals are more rapid than the reverse addition steps. The second stage is controlled by the onset of dissociation of hydrogen peroxide. Results also show that in some cases, the first stage ignition takes place during the compression stroke in the rapid compression machine, making the interpretation of the experiments somewhat more complex than …

We have designed a new experiment (E923) at the BNL-AGS to search for the T-violating polarization of the muon normal to the decay plane of the K{sup +} {yields} {mu}{sup +}{pi}{sup 0}{nu} decay. The experiment aims to search for T-violation beyond the Standard Model; such a search is motivated by the need for a stronger CP violation source to account for the baryon asymmetry of the Universe. The experiment will be performed with in-flight decays from an intense (2 x 10{sub 7} K{sup +}/sec) 2 GeV/c separated K{sup +} beam in an existing beam-line at the AGS. We expect to analyze more than 10{sup 9} events to obtain the sensitivity of {delta}P{sub 2} = {+-} 0.00013 at 1 {sigma}, corresponding to the sensitivity of {+-}0.0007 to Im{xi}, an improvement by 40 over the present limit on the same measurement.

An excited minimum, or false vacuum, gives rise to a highly elongated superdeformed (SD) nucleus. A brief review of superdeformation is given, with emphasis on the tunneling from the false to the true vacuum, which occurs in the feeding and decay of SD bands. During the feeding process the tunneling is between hot states, while in the decay it is from a cold to a hot state. The {gamma} spectra connecting SD and normal-deformed (ND) states provide information on several physics issues: the decay mechanism; the spin/parity quantum numbers, energies and microscopic structures of SD bands; the origin of identical SD bands; the quenching of pairing with excitation energy; and the chaoticity of excited ND states at 2.5-5 MeV. Other examples of tunneling in nuclei, which are briefly described, include the possible role of tunneling in {Delta}I = 4 bifurcation in SD bands, sub-barrier fusion and proton emitters.

High-resolution, gamma- and X-my spectrometry are used routinely in nuclear materials safeguards vetication measurements. These measurements are mostly performed with high-purity germanium (HJ?Ge) detectors, which require cooling at liquid-nitrogen temperatures, thus limiting their utility in field and unattended safeguards measurement applications. Sodium iodide (NaI) scintillation detectors do not require cooling, but their energy resolution (10% at 122 keV) is insu&ient for many verification measurements. Semiconductor detectors that operate at room temperatures, such as cadmium-zinc-telhuide (CZT) detectors, with energy resolution performance reaching 2.0% at 122 keV may be used for certain safeguards verification applications. We have developed hardware to utilize CZT detectors in X- and gamma-ray measurement, systems and software to apply such a system in measuring 215U enrichment for safeguards verification purposes. The paper reports on the CZT detector-based measurement system and measurement results obtained with it. The paper also discusses work on additional improvements to broaden the applications of the

Historically, thermal hydraulics analyses on Large Break Loss of Coolant Accidents (LOCA) have been focused on the transients within the reactor or steam generator. Few have studied the effects of steam blowdown on the containment building. This paper discusses some theoretical issues as well as presenting numerical and experimental results of the blowdown tests performed at the Purdue University Multi-Dimensional Integrated Test Assembly (PUMA).

A magnetically assisted chemical separation (MACS) process was developed earlier at Argonne National Laboratory (ANL). This compact process was designed for the separation of transuranics (TRU) and radionuclides from the liquid waste streams that exist at many DOE sites, with an overall reduction in waste volume requiring disposal. The MACS process combines the selectivity afforded by solvent extractant/ion exchange materials with magnetic separation to provide an efficient chemical separation. Recently, the MACS process has been evaluated with acidic organophosphorus extractants for hazardous metal recovery from waste solutions. Moreover, process scale-up design issues have been addressed with respect to particle filtration and recovery. Two acidic organophosphorus compounds have been investigated for hazardous metal recovery, bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex{reg_sign} 272) and bis(2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanex{reg_sign} 301). Coated onto magnetic microparticles, these extractants demonstrated superior recovery of hazardous metals from solution, relative to what was expected on the basis of results from solvent extraction experiments. The results illustrate the diverse applications of MACS technology for dilute waste streams. Preliminary process scale-up experiments with a high-gradient magnetic separator at Oak Ridge National Laboratory have revealed that very low microparticle loss rates are possible.

Fluid flow rate in high temperature and pressure vessels can be difficult to measure due to the associated harsh environment, inaccessible locations and pressure boundary integrity concerns. However, by using quick response miniature thermocouples to measure the naturally occurring temperature variations within the flow, the fluid velocity can be inferred from the transit time analysis. This flow measurement technique has other advantages such as the flow profile is not significantly disturbed, no additional flow restrictions introduced and the system fiction factor is not increased. Furthermore, since the measured flow rate is generally unaffected by the global system dynamics, such as heat increases or losses, as well as changes in the flow regimes, the location of the thermocouple pairs is extremely flexible. Due to the mentioned advantages, the thermocouple cross-correlation flow measurement method has been developed for use at the Purdue University Multi-Dimensional Integral Test Assembly (PUMA). Currently, thermocouple cross-correlation technique is used to measure the Reactor Pressure Vessel downcomer fluid velocity and the suppression pool in-vessel natural circulation velocity.

Polycrystalline Pb(Zr{sub 0.6}Ti{sub 0.4})O{sub 3} (PZT) thin films, 3000-6000 {angstrom} thick, have been grown by metal-organic chemical vapor deposition (MOCVD) on (111)Pt/Ti/SiO{sub 2}/Si substrates at temperatures as low as 450-525 C. Random and (111)-oriented, or occasionally (100)-oriented, PZT films can be deposited directly on (111)Pt/Ti/SiO{sub 2}/Si. In addition, highly (100)-oriented films can be deposited consistently by using 150-250 {angstrom} thick (100)-oriented PbTiO{sub 3} (PT) or TiO{sub 2} as a template. Films were characterized by X-ray diffraction, electron microscopy, and electrical measurements. The as-grown (100)-oriented films on (111)Pt/TiSiO{sub 2}/Si substrates exhibited dielectric constants ({var_epsilon}{sub r}) of up to 600, remnant polarization (P{sub r}) of 40 {micro}C/cm{sup 2}, coercive field of 55 kV/cm, and breakdown field of 2-6 x 10{sub 7} V/m.

Simulations of Cl plasma etch of Si surfaces with MD techniques agree reasonably well with the available experimental information on yields and surface morphologies. This information has been supplied to a Monte Carlo etch profile resulting in substantial agreement with comparable inputs provided through controlled experiments. To the extent that more recent measurements of etch rates are more reliable than older ones, preliminary MD simulations using bond-order corrections to the atomic interactions between neighboring Si atoms on the surface improves agreement with experiment through an increase in etch rate and improved agreement with XPS measurements of surface stoichiometry. Thermochemical and geometric analysis of small Si-Br molecules is consistent with the current notions of the effects of including brominated species in etchant gases.

We have shown that PSLCs are capable of forming photorefractive gratings that operate in the thick grating regime. Polymer stabilization alters the charge transport and trapping characteristics of LCs, resulting in longer lived gratings, while maintaining the advantages of high orientational birefringence within LCs. Furthermore, very low applied electric fields (800 V/cm) and low optical intensities (100 mW/cm{sup 2}) are required to create large photorefractive effects in these materials. It is expected that optimization of the redox potentials of the chromophores within the PSLCs will continue to improve the performance of these materials.

Lattice parameters for a crystalline material can be obtained by several methods, notably by analyzing x-ray powder diffraction patterns. By utilizing a computer program to fit a pattern, one can follow the evolution or subtle changes in a structure of a crystalline species in different environments. This work involves such a study for an essential component of the ceramic waste form that is under development at Argonne National Laboratory. Zeolite 4A and zeolite 5A are used to produce two different types of waste forms: a glass-bonded sodalite and a glass-bonded zeolite, respectively. Changes in structure during production of the waste forms are discussed. Specific salt-loadings in the sodalite waste form are related to relative peak intensities of certain reflections in the XRD patterns. Structural parameters for the final waste forms will also be given and related to leachability under standard conditions.

Laboratory applications for the analysis of PCBS (polychlorinated biphenyls) in environmental matrices such as soil/sediment/sludge and oil/waste oil were evaluated for potential reduction in waste, source reduction, and alternative techniques for final determination. As a consequence, new procedures were studied for solvent substitution, miniaturization of extraction and cleanups, minimization of reagent consumption, reduction of cost per analysis, and reduction of time. These new procedures provide adequate data that meet all the performance requirements for the determination of PCBS. Use of the new procedures reduced costs for all sample preparation techniques. Time and cost were also reduced by combining the new sample preparation procedures with the power of fast gas chromatography. Separation of Aroclor 1254 was achieved in less than 6 min by using DB-1 and SPB-608 columns. With the greatly shortened run times, reproducibility can be tested quickly and consequently with low cost. With performance-based methodology, the applications presented here can be applied now, without waiting for regulatory approval.

Ab initio molecular orbital calculations have been used to investigate the influence of corannulene's curved carbon lattice (C{sub 20}H{sub 10}) on lithium intercalation. This has been approximated by investigating the reaction of lithium atoms with either the corannulene molecule directly or with a sandwich structure formed from two corannulene molecules. In the first case, one corannulene molecule, three, six and seven lithiums have been used to form Li{sub 3}(C{sub 20}H{sub 10}), Li{sub 6}(C{sub 20}H{sub 10}) and Li{sub 7}(C{sub 20}H{sub 10}). The last complex has a lithium to carbon ratio of 1:2.86 indicative of a high capacity lithium carbon anode versus the 1:6 ratio found in stage 1 lithium intercalated graphite. The change in Gibbs energy for formation of Li{sub 3}(C{sub 20}H{sub 10}) with a multiplicity of 4 (3 unpaired electrons) is -4.75 kcal/mole. However, when a multiplicity of 2 is used (1 unpaired electron), the change in Gibbs energy is -8.49 kcal/mole. The change in Gibbs energy for formation of Li{sub 6}(C{sub 20}H{sub 10}) and Li{sub 7}(C{sub 20}H{sub 10}) (multiplicity of 2) are -26.48 and -26.47 kcal/mole, respectively. In all the lithium corannulene complexes described, each complex has a molecular orbital composed only of lithium orbitals, indicative of lithium cluster …

The desire to reduce the time and cost of design engineering on new components or to validate existing designs in new applications is stimulating the development of modeling and simulation tools. The authors are applying a model-based design approach to low and moderate rate versions of the Li/SOCl{sub 2} D-size cell with success. Three types of models are being constructed and integrated to achieve maximum capability and flexibility in the final simulation tool. A phenomenology based electrochemical model links performance and the cell design, chemical processes, and material properties. An artificial neural network model improves computational efficiency and fills gaps in the simulation capability when fundamental cell parameters are too difficult to measure or the forms of the physical relationships are not understood. Finally, a PSpice-based model provides a simple way to test the cell under realistic electrical circuit conditions. Integration of these three parts allows a complete link to be made between fundamental battery design characteristics and the performance of the rest of the electrical subsystem.

This article discusses low-level copper concentration measurements in silicon wafers using trace-element accelerator mass spectrometry.

The National Ignition Facility (NIF), being built at Lawrence Livermore National Laboratory (LLNL) will utilize a 18 MJ glass laser to study inertial confinement fusion This laser will be driven by a power conditioning system which must simultaneously deliver over 260 MJ of electrical energy to the nearly 7700 flashlamps The power conditioning system is divided into independent modules that store, shape and deliver pulses of energy to the flashlamps The NIF power conditioning system which is being designed and built by Sandia National Laboratory (SNL) in collaboration with LLNL and industrial partners, is a different architecture from any laser power conditioning system previously built at LLNL This particular design architecture was chosen as the most cost- effective way to reliably deliver the large amount of energy needed for NIF This paper will describe the development and design of the NIF power conditioning system It will discuss the design objectives as well as the key design issues and technical hurdles that are being addressed in an ongoing component development and system validation program being supported by both SNL and LLNL.

As a result of health and safety issues surrounding the use of radioactive materials on coated optical components, there has been renewed interest in coating materials whose optical and mechanical properties approach those offered by their radioactive counterparts. Due to the radioactive nature of ThF{sub 4} and its widespread use in optical coatings, the coating industry is examining other low index and non-radioactive fluorides as possible alternatives. In this paper, the authors present the results of an experimental study on the optical and mechanical properties of thermally evaporated ThF{sub 4}, DyF{sub 3}, CeF{sub 3}, LiF, HfF{sub 4}, IRX, and IRB thin films, where the materials were deposited at different substrate temperatures. The objective is to examine this series of fluorides under comparable deposition conditions and with respect to such material properties as: n and k, film stress, and environmental stability. The optical constants of these fluorides were evaluated over the wavelength region from 1.0 {micro}m to 12.5 {micro}m.

Glass dissolution rates decrease dramatically as glasses approach "saturation" with respect to the leachate solution. This effect may lower the dissolution rate to 1/100 to 1/1000 of the unsaturated rate. Although rate controls on glass dissolution are best understood for conditions far from saturation, most repository sites are chosen where water fluxes are minimal, and therefore the waste glass is most likely to dissolve under conditions close to saturation. Our understanding of controls on dissolution rates close to saturation, versus far from saturation, are therefore of greater significance for assessing release rates of radionuclides from repositories. The key term in the rate expression used to predict glass dissolution rates close to saturation is the affinity term, which accounts for saturation effects on dissolution rates. The form of the affinity term and parameters used to model glass dissolution are clearly critical for accurate estimates of glass performance in a repository. The concept of saturation with respect to glass dissolution is problematic because of the thermodynamically unstable nature of glass. Saturation implies similar rates of forward (dissolution) and back (precipitation) reactions, but glasses cannot precipitate from aqueous solutions; there can be no back reaction to form glass. However experiments have shown that …

The US is currently evaluating the use of MOX fuel in commercial LWR's for reducing weapons grade Pu stockpiles. The design and licensing processes will require that the validity of the nuclear data libraries and codes used in the effort be demonstrated. Unfortunately, there are only a very limited number of relatively old and non representative integral experiments' freely available to the US programs. This lack of adequate experimental data can be partially remediated by comparing the results of well validated European codes with the results of candidate US codes. The demonstration can actually be divided in two components: a code to code (Monte Carlo) comparison can easily demonstrate the validity and limits of the proposed algorithms; and the performances of nuclear data libraries should be compared, major trends should be observed, and their origins should be explained in terms of differences in evaluated nuclear data; In this paper, we have compared the performances of the JEF-2.2 and ENDF/B-VI.4 libraries for a series of benchmarks for k{sub eff}, void worth, and pin power distributions. Note that JEF-2.2 has been extensively validated for MOX applications.

Existing methods for qualifying digital system software for use in safety critical systems are expensive and are based on inferences that are of doubtful validity. This report on work-in-progress describes a new approach to qualifying a class of small safety systems that can meet a number of design restrictions, where the restrictions are carefully crafted to permit safety qualification to be determined by means of static analysis of the software combined with a limited amount of testing. This approach differs from attempts to qualify unrestricted programs in the general case. Work that has been accomplished towards this goal is discussed in summary terms. The technique relies on transforming a program into a form of directed graph known as a flowgraph. Existing testing theory is used, sometimes with minor modifications, to derive a set of design restrictions that permit reasoning about safety properties of the program, based on analysis and limited testing. Future work required to complete the research is outlined.

The NIF target chamber beam dumps must survive high x-ray, laser, ion, and shrapnel exposures without excessive generation of vapors or particulate that will contaminate the final optics debris shields, thereby making the debris shields susceptible to subsequent laser damage. The beam dumps also must be compatible with attaining and maintaining the required target chamber vacuum and must not activate significantly under high neutron fluxes. Finally, they must be developed, fabricated, and maintained for a reasonable cost. The primary challenge for the beam dump is to survive up to 20 J/cm{sup 2} of lpm light and 1 - 2 J/cm{sup 2} of nominally 200 - 350 eV blackbody temperature x rays. Additional threats include target shrapnel, and other contamination issues. Designs which have been evaluated include louvered hot-pressed boron carbide (B{sub 4}C) or stainless steel (SS) panels, in some cases covered with transparent Teflon film, and various combinations of inexpensive low thermal expansion glasses backed by inexpensive absorbing glass. Louvered designs can recondense a significant amount of ablated material that would otherwise escape into the target chamber. Transparent Teflon was evaluated as an alternative way to capture ablated material. The thin Teflon sheet would need to be replaced after each …