Completion of zero-power critical experiments with the ORNL Health Physics Research Reactor is reported. A description is given concerning these experiments which were used to determine the critical size, fission-rate distributions, reactivity calibrations of its movable parts, the temperature coefficient of reactivity, and the reactivity effects of the presence of neutron- reflecting materials adjacent to the reactor. (J.R.D.)

The time-dependent behavior was investigated of the neutron population in an unreflected unmoderated cylindrical assembly of 90 wt.% U (93.2 wt.% U/sup 235/), 10 wt.% Mo alloy following rapid establishment of a super-prompt critical c ondition with negligible initial neutron population. Reactivity increases up to 11 cents above prompt critical resulted in bursts yielding as many as 1.8 x 10/ sup 17/ fissions with reactor periods as short as 16 mu sec and temperature increases as large as 400 deg C. Pressure waves generated in a portion of the core held in position by an electromagnet for bursts greater than ~6 x 10/sup 16/ fissions initiated the removal of this section about 225 mu sec after the peak burst. (auth)

Data and information are presented concerning analyses of PL-2 transient performance, normal startup and shutdown procedures, and shield design. (J.R.D.)

The Lawrence Livermore National Laboratory (LLNL) has an active interest in the synthesis of new polysiloxanes as base polymers for cellular silicone materials. These elastomers have properties uniquely suited to very specific engineering requirements. While the polymers which we have prepared via random equilibrium of various cyclic tetrasiloxanes have adequate properties for certain applications, there is evidence to suggest that alternating block polysiloxanes prepared via condensation-polymerization techniques have properties more suited to our end uses as flexible foam materials (cushions). The synthetic sequence developed to prepare these materials involves reactions of functionally terminated (silylamino and silanol) polysiloxane oligomers to produce alternating multiblock (ABAB...) materials of high molecular weight. Dialkylamines are condensation byproducts in this reaction. The analysis and characterization of these multiblock polymers is reported.

A measurement control (MC) program should be an integral part of every nondestructive assay measurement system used for the assay of special nuclear materials. This report describes an MC program for plutonium isotopic composition measurements using high-resolution gamma-ray spectroscopy. This MC program emphasizes the standardization of data collection procedures along with the implementation of internal and external measurement control checks to provide the requisite measurement quality assurance. This report also describes the implementation of the MC program in the isotopic analysis code GRPAUT. Recommendations are given concerning the importance and frequency of the various MC checks in order to ensure a successful implementation of the MC procedures for the user's application.

This report contains brief discussions on topics of high-pressure sciences, astrophysics, and geosciences. (LSP)

The process of longitudinal compression of a drifting heavy ion pulse to be used as an ICF driver is examined with the aid of particle simulation. Space charge forces play a vital role in halting compression before the final focus lens system is reached. This must take place with minimal growth of transverse emittance and momentum spread. Of particular concern is the distortion of longitudinal phase space by the rounded transverse profile of the longitudinal self-electric field.

Antiferromagnetic (AFM) NiO thin films are grown epitaxially on vicinal Ag(118) substrate and investigated by x-ray linear dichroism (XLD). We find that the NiO AFM spin exhibits an in-plane spin reorientation transition from parallel to perpendicular to the step edges with increasing the NiO film thickness. In addition to the conventional L{sub 2} adsorption edge, x-ray linear dichroism (XLD) effect at the Ni L{sub 3} adsorption edge is also measured and analyzed. The result identifies a small energy shift of the L{sub 3} peak. Temperature-dependent measurement confirms that the observed XLD effect in this system at the normal incidence of the x-rays originates entirely from the NiO magnetic ordering.

For the first time in history, direct and indirect detection techniques have enabled the exploration of the environments of nearby stars on scales comparable to the size of our solar system. Precision Doppler measurements have led to the discovery of the first extrasolar planets, while high-contrast imaging has revealed new classes of objects including dusty circumstellar debris disks and brown dwarfs. The ability to recover spectrophotometry for a handful of transiting exoplanets through secondary-eclipse measurements has allowed us to begin to study exoplanets as individual entities rather than points on a mass/semi-major-axis diagram and led to new models of planetary atmospheres and interiors, even though such measurements are only available at low SNR and for a handful of planets that are automatically those most modified by their parent star. These discoveries have galvanized public interest in science and technology and have led to profound new insights into the formation and evolution of planetary systems, and they have set the stage for the next steps--direct detection and characterization of extrasolar Jovian planets with instruments such as the Gemini Planet Imager (GPI). As discussed in Volume 1, the ability to directly detect Jovian planets opens up new regions of extrasolar planet phase …

Gas storage is a critical element in the natural gas industry. Producers, transmission and distribution companies, marketers, and end users all benefit directly from the load balancing function of storage. The unbundling process has fundamentally changed the way storage is used and valued. As an unbundled service, the value of storage is being recovered at rates that reflect its value. Moreover, the marketplace has differentiated between various types of storage services, and has increasingly rewarded flexibility, safety, and reliability. The size of the natural gas market has increased and is projected to continue to increase towards 30 trillion cubic feet (TCF) over the next 10 to 15 years. Much of this increase is projected to come from electric generation, particularly peaking units. Gas storage, particularly the flexible services that are most suited to electric loads, is critical in meeting the needs of these new markets. In order to address the gas storage needs of the natural gas industry, an industry-driven consortium was created--the Gas Storage Technology Consortium (GSTC). The objective of the GSTC is to provide a means to accomplish industry-driven research and development designed to enhance operational flexibility and deliverability of the Nation's gas storage system, and provide a …

We present a new technique to accelerate the convergence of the folded spectrum method in empirical pseudopotential band edge state calculations for colloidal quantum dots. We use bulk band states of the materials constituent of the quantum dot to construct initial vectors and a preconditioner. We apply these to accelerate the convergence of the folded spectrum method for the interior states at the top of the valence and the bottom of the conduction band. For large CdSe quantum dots, the number of iteration steps until convergence decreases by about a factor of 4 compared to previous calculations.

This paper reports the results in the effort to destabilize lithium borohydride for reversible hydrogen storage. A number of metals, metal hydrides, metal chlorides and complex hydrides were selected and evaluated as the destabilization agents for reducing dehydriding temperature and generating dehydriding-rehydriding reversibility. It is found that some additives are effective. The Raman spectroscopic analysis shows the change of B-H binding nature.

Seasonally managed wetlands in the Grasslands Basin ofCalifornia's San Joaquin Valley provide food and shelter for migratorywildfowl during winter months and sport for waterfowl hunters during theannual duck season. Surface water supply to these wetland contain saltwhich, when drained to the San Joaquin River during the annual drawdownperiod, negatively impacts downstream agricultural riparian waterdiverters. Recent environmental regulation, limiting discharges salinityto the San Joaquin River and primarily targeting agricultural non-pointsources, now addresses return flows from seasonally managed wetlands.Real-time water quality management has been advocated as a means ofmatching wetland return flows to the assimilative capacity of the SanJoaquin River. Past attempts to build environmental monitoring anddecision support systems to implement this concept have failed forreasons that are discussed in this paper. These reasons are discussed inthe context of more general challenges facing the successfulimplementation of environmental monitoring, modelling and decisionsupport systems. The paper then provides details of a current researchand development project which will ultimately provide wetland managerswith the means of matching salt exports with the available assimilativecapacity of the San Joaquin River, when fully implemented. Manipulationof the traditional wetland drawdown comes at a potential cost to thesustainability of optimal wetland moist soil plant habitat in thesewetlands - hence the project …

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The objective of this paper is to assess proposed transuranic waste accident analysis guidance and recent software improvements in a Windows-OS version of MACCS2 that allows the inputting of parameter uncertainty. With this guidance and code capability, there is the potential to perform a quantitative uncertainty assessment of unmitigated accident releases with respect to the 25 rem Evaluation Guideline (EG) of DOE-STD-3009-94 CN3 (STD-3009). Historically, the classification of safety systems in a U.S. Department of Energy (DOE) nuclear facility's safety basis has involved how subject matter experts qualitatively view uncertainty in the STD-3009 Appendix A accident analysis methodology. Specifically, whether consequence uncertainty could be larger than previously evaluated so the site-specific accident consequences may challenge the EG. This paper assesses whether a potential uncertainty capability for MACCS2 could provide a stronger technical basis as to when the consequences from a design basis accident (DBA) truly challenges the 25 rem EG.

An international, multiple-code benchmark test (BMT) studyis being conducted within the international DECOVALEX project to analysecoupled thermal, hydrological, mechanical and chemical (THMC) processesin the excavation disturbed zone (EDZ) around emplacement drifts of anuclear waste repository. This BMT focuses on mechanical responses andlong-term chemo-mechanical effects that may lead to changes in mechanicaland hydrological properties in the EDZ. This includes time-de-pendentprocesses such as creep, and subcritical crack, or healing of fracturesthat might cause "weakening" or "hardening" of the rock over the longterm. Five research teams are studying this BMT using a wide range ofmodel approaches, including boundary element, finite element, and finitedifference, particle mechanics, and elasto-plastic cellular automatamethods. This paper describes the definition of the problem andpreliminary simulation results for the initial model inception part, inwhich time dependent effects are not yet included.

This paper presents preliminary results from an ongoing post-irradiation analysis of materials that have been irradiated at the Brookhaven National Laboratory (BNL) Isotope facility. The effort is part of an experimental study that focuses on how prone to irradiation damage these materials are and thus what is their potential in playing the role of high power targets in the neutrino superbeam and the muon collider initiatives.

The lifetime for the decay of a {pi} meson into {mu} meson and neutral particle was first measured by Richardson and later by Martinelli and Panofsky. The method was the same in both cases: The fraction of {pi} mesons surviving various times of flight is measured by placing photographic detectors at various path lengths from the target. In the experiment reported here we observe the time lag between the two bursts of fluorescence due to mesons decaying in a scintillation crystal. The first burst is due to the stopping of the entering {pi} meson, the second to the {mu}-meson. As is shown in Fig. 1, a particle penetrating the first and into the second crystal starts the sweep (10{sup -8} sec/mm) of an oscilloscope. The pulses in the second crystal are delayed 0.5 x 10{sup -6} sec to allow the sweep to start and brighten and are then photographed. If the responsible particle is a {pi}{sup +} meson which stops in the crystal, it undergoes {pi}-{mu} decay and two pulses appear on the trace. The {mu}{sup +} meson has a range of only 2 mm in the crystal. If its decay electron is detected some time (.5-2.5 x 10{sup -6} …

Address both thickness dependence of Jc, in thick film YBCO coated conductors through an application of a suite of new measurement techniques to thick film wire samples produced by commercially viable coated conductor technologies.

Modern and technologically up-to-date facilities and systems infrastructure are necessary to accommodate today's research environment. In response, Lawrence Livermore National Laboratory (LLNL) has a continuing commitment to develop and apply effective management models and processes to maintain, modernize, and upgrade its facilities to meet the science and technology mission. The Facility Modernization Pilot Study identifies major subsystems of facilities that are either technically or functionally obsolete, lack adequate capacity and/or capability, or need to be modernized or upgraded to sustain current operations and program mission. This study highlights areas that need improvement, system interdependencies, and how these systems/subsystems operate and function as a total productive unit. Although buildings are 'grandfathered' in and are not required to meet current codes unless there are major upgrades, this study also evaluates compliance with 'current' building, electrical, and other codes. This study also provides an evaluation of the condition and overall general appearance of the structure.

The spatial distribution of copper ions and atoms in high power impulse magnetron sputtering (HIPIMS) discharges was determined by (i) measuring the ion current to electrostatic probes and (ii) measuring the film thickness by profilometry. A set of electrostatic and collection probes were placed at different angular positions and distances from the target surface. The angular distribution of the deposition rate and the average charge state of the copper species (including ions and neutrals) were deduced.The discharge showed a distinct transition to a high current mode dominated by copper self-sputtering when the applied voltage exceeded the threshold of 535 V. For a lower voltage, the deposition rate was very low and the average charge state was found to be less than 0.4. For higher voltage (and average power), the absolute deposition rates were much higher, but they were smaller than the corresponding direct current (DC) rates if normalized to the same average power. At the high voltage level, the spatial distribution of the average charge state showed some similarities with the distribution of the magnetic field, suggesting that the generation and motion of copper ions is affected by magnetized electrons. At higher voltage, the average charge state increases with the …

As part of the ongoing international DECOVALEX project, fourresearch teams used five different models to simulate coupled thermal,hydrological, and mechanical (THM) processes near underground wasteemplacement drifts. The simulations were conducted for two genericrepository types, one with open and the other with back-filled repositorydrifts, under higher and lower post-closure temperature, respectively. Inthe completed first model inception phase of the project, a goodagreement was achieved between the research teams in calculating THMresponses for both repository types, although some disagreement inhydrological responses are currently being resolved. Good agreement inthe basic thermal-mechanical responses was also achieved for bothrepository types, even though some teams used relatively simplifiedthermal-elastic heat-conduction models that neglect complex near-fieldthermal-hydrological processes. The good agreement between the complexand simplified process models indicates that the basic thermal-mechanicalresponses can be predicted with a relatively high confidencelevel.

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The intent of the computer code GAMIDEN is to help identify isotopes by their gamma-ray emissions and thus to assist in the nondestructive assay of unknown materials. From both radioactive decays and neutron captures, GAMIDEN searches GAMTOT83, a file of gamma-ray spectra, for matches with observed photon energies. This report describes the search procedure, outlines the use of the code, and gives an example. The code is designed to operate on the CRAY 1 computer at Lawrence Livermore National Laboratory (LLNL). It is written in standard Fortran (ANSI) for the most part but contains some LRLTRAN instructions to make use of the Livermore time-sharing system (LTSS). The code uses about 545,000 words of memory. Typical problems run in about 45 s. The source program and the data file are available on request.