All stations planned for the International Monitoring System (IMS) must be certified by the Provisional Technical Secretariat (PTS) prior to acceptance to ensure that the monitoring stations initially meet the required specifications. Working Group B of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty has established requirements for the quality, availability, and surety of data received at the International Data Centre (IDC). These requirements are verified by the PTS during a 3-component process that includes initial station assessment, testing and evaluation, and certification. Sandia National Laboratories has developed procedures, facilities, and tools that can be used to assist in evaluating IMS stations for compliance with certification requirements. System evaluation includes station design reviews, component testing, and operational testing of station equipment. Station design is evaluated for security and reliability considerations, and to ensure that operational procedures and documentation are adequate. Components of the station are tested for compliance with technical specifications, such as timing and noise levels of sampled data, and monitoring of tamper detection equipment. Data sent from the station in an IMS-standard format (CD-1 or IMS-1) are analyzed for compliance with the specified protocol and to ensure that the station data (sensor and state-of-health) are accurately transmitted. Data …

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Sandia National Laboratories has continued to evaluate the performance of infrasound sensors that are candidates for use by the International Monitoring System (IMS) for the Comprehensive Nuclear-Test-Ban Treaty Organization. The performance criteria against which these sensors are assessed are specified in ``Operational Manual for Infra-sound Monitoring and the International Exchange of Infrasound Data''. This presentation includes the results of efforts concerning two of these sensors: (1) Chaparral Physics Model 5; and (2) CEA MB2000. Sandia is working with Chaparral Physics in order to improve the capability of the Model 5 (a prototype sensor) to be calibrated and evaluated. With the assistance of the Scripps Institution of Oceanography, Sandia is also conducting tests to evaluate the performance of the CEA MB2000. Sensor models based on theoretical transfer functions and manufacturer specifications for these two devices have been developed. This presentation will feature the results of coherence-based data analysis of signals from a huddle test, utilizing several sensors of both types, in order to verify the sensor performance.

The density of threading dislocations (TD) in GaN grown directly on flat sapphire substrates is typically greater than 10{sup 9}/cm{sup 2}. Such high dislocation densities degrade both the electronic and photonic properties of the material. The density of dislocations can be decreased by orders of magnitude using cantilever epitaxy (CE), which employs prepatterned sapphire substrates to provide reduced-dimension mesa regions for nucleation and etched trenches between them for suspended lateral growth of GaN or AlGaN. The substrate is prepatterned with narrow lines and etched to a depth that permits coalescence of laterally growing III-N nucleated on the mesa surfaces before vertical growth fills the etched trench. Low dislocation densities typical of epitaxial lateral overgrowth (ELO) are obtained in the cantilever regions and the TD density is also reduced up to 1 micrometer from the edge of the support regions.

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The 1994 Accident Sequence Precursor (ASP) human reliability analysis (HRA) methodology was developed for the U.S. Nuclear Regulatory Commission (USNRC) in 1994 by the Idaho National Engineering and Environmental Laboratory (INEEL). It was decided to revise that methodology for use by the Simplified Plant Analysis Risk (SPAR) program. The 1994 ASP HRA methodology was compared, by a team of analysts, on a point-by-point basis to a variety of other HRA methods and sources. This paper briefly discusses how the comparisons were made and how the 1994 ASP HRA methodology was revised to incorporate desirable aspects of other methods. The revised methodology was renamed the SPAR HRA methodology.

For the WIPP, chemical and physical characteristics of MgO suggest it to be the most beneficial backfill choice, particularly because it has the ability to buffer the aqueous chemical conditions to control actinide volubility. In the current experimental program, the authors are developing a technical basis for taking credit for the complete set of attributes of MgO in geochemical, hydrogeological, and geomechanical technical areas, resulting in an improved conceptual model for the WIPP such as the following. Water uptake by MgO will delay the development of mobile actinides and gas generation by microbes and corrosion. Reduced gas generation will reduce or even eliminate spallings releases. As MgO hydrates, it swells, reducing porosity and permeability, which will inhibit gas flow in the repository, in turn reducing spallings releases. Hydration will also result in a self-sealing mechanism by which water uptake and swelling of MgO adjacent to a groundwater seep cuts off further seepage. Reaction with some groundwaters will produce cementitious materials, which will help to cement waste particles or produce a cohesive solid mass. Larger particles are less likely to be entrained in a spallings release. If sufficient water eventually accumulates in a repository to support microbial gas generation, magnesium carbonate …

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Partially premixed turbulent flames can develop flow regimes where triple flames emerge consisting of essentially premixed and non-premixed zones. The description of such phenomena requires a criterion for the detection of such zones. Such a criterion can be based on a wide range of variables including reaction rates, mass fractions of radicals, etc. These variables are not necessarily suitable for the limit of infinitely fast reactions, for instance, reaction rates are obviously not bounded in this limit. Hence a new single scalar variable based on geometric properties of mixture fraction and non-conserved variables is constructed, that allows the detection of finite rate and, in particular, triple flame domains and is bounded in the limit of infinitely fast reactions. This is first done for systems with simplified chemistry described by two variables and then generalized to combustion with complex chemistry. A pdf-sdf formalism is then outlined for the local thermodynamic state conditioned upon the degree of finite rate effects.

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Emergency operating procedures (EOPs) in nuclear plants guide operators in handling significant process disturbances. Historically these procedures have been paper-based. More recently, computer-based procedure (CBP) systems have been developed to improve the usability of EOPs. The objective of this study was to establish human factors review guidance for CBP systems based on a technically valid methodology. First, a characterization of CBPs was developed for describing their key design features, including both procedure representation and functionality. Then, the research on CBPs and related areas was reviewed. This information provided the technical basis on which the guidelines were developed. For some aspects of CBPs the technical basis was insufficient to develop guidance; these aspects were identified as issues to be addressed in future research.

The effects of unsteady strain rate on the burning velocity of hydrogen-air premixed flames are studied in an opposed nozzle configuration. The numerical method employs adaptive time integration of a system of differential-algebraic equations. Detailed hydrogen-air kinetic mechanism and transport properties are considered. The equivalence ratio is varied from lean to rich premixtures in order to change the effective Lewis number. Steady Markstein numbers for small strain rate are computed and compared with experiment. Different definitions of flame burning velocity are examined under steady and unsteady flow conditions. It is found that, as the unsteady frequency increases, large deviations between different flame speeds are noted depending on the location of the flame speed evaluation. Unsteady flame response is investigated in terms of the Markstein transfer function which depends on the frequency of oscillation. In most cases, the flame speed variation attenuates at higher frequencies, as the unsteady frequency becomes comparable to the inverse of the characteristic flame time. Furthermore, unique resonance-like behavior is observed for a range of rich mixture conditions, consistent with previous studies with linearized theory.

An important frontier in ultrafast science is the application of femtosecond x-ray pulses to the study of structural dynamics in condensed matter. We show that femtosecond laser pulses can be used to generate high-brightness, tunable, femtosecond x-ray pulses from a synchrotron. Performance of existing and proposed femtosecond x-ray beamlines at the Advanced Light Source synchrotron are discussed.

The Human-System Interface Design Review Guideline (NUREG-0700, Revision 1) was developed by the US Nuclear Regulatory Commission (NRC) to provide human factors guidance as a basis for the review of advanced human-system interface technologies. The guidance consists of three components: design review procedures, human factors engineering guidelines, and a software application to provide design review support called the ``Design Review Guideline.'' Since it was published in June 1996, Rev. 1 to NUREG-0700 has been used successfully by NRC staff, contractors and nuclear industry organizations, as well as by interested organizations outside the nuclear industry. The NRC has committed to the periodic update and improvement of the guidance to ensure that it remains a state-of-the-art design evaluation tool in the face of emerging and rapidly changing technology. This paper addresses the current research to update of NUREG-0700 based on the substantial work that has taken place since the publication of Revision 1.

Recently developed short-contact-time reactors (SCTR), consisting of porous alumina monoliths coated with platinum, have been shown to produce ethylene from rich ethane/oxygen(hydrogen) mixtures with yields and selectivities comparable to conventional steam cracking, using a reactor of much smaller size. Although the overall mechanism is clearly autothermal and catalytic, the details, in particular the relative contributions of heterogeneous and homogeneous chemistry, are a matter of considerable debate. Recent experiments show that reactor performance can be further enhanced by dripping a dilute platinum solution onto the SCTR front face during reaction, resulting in catalyst deposition within only a short (several millimeter) zone of the reactor. The authors have undertaken a computational study of this system, using two-dimensional computational fluid dynamics simulations with full heat and mass transport and detailed heterogeneous and homogeneous kinetic mechanisms. The results indicate that front-face catalyst loading enhances reactor performance by limiting the opportunity for heterogeneous ethane reactions that produce methane. As a result, ethylene selectivity increases and CH{sub 4} selectivity decreases. The results strongly support a mechanism recently proposed by the authors, in which rapid, heterogeneous oxidation of adsorbed hydrogen consumes most of the oxygen. The resulting heat is then released to the gas phase, causing homogeneous …

Organizational culture surveys of research facilities conducted several years ago and archival occupational injury reports were used to determine whether differences in safety performance are related to general organizational factors or to ''safety culture'' as reflected in specific safety-related dimensions. From among the organizations surveyed, a pair of facilities was chosen that were similar in size and scientific mission while differing on indices of work-related injuries. There were reliable differences in organizational style between the facilities, especially among workers in environment, safety, and health functions; differences between the facilities (and among job categories) on the safety scale were more modest and less regular.

The precise angle monitoring is a very important metrology task for research, development and industrial applications. Autocollimator is one of the most powerful and widely applied instruments for small angle monitoring, which is based on the principle of geometric optics. In this paper the authors introduce a new precise angle monitoring system, Pencil-beam Angle Monitor (PAM), base on pencil beam interferometry. Its principle of operation is a combination of physical and geometrical optics. The angle calculation method is similar to the autocollimator. However, the autocollimator creates a cross image but the precise pencil-beam angle monitoring system produces an interference fringe on the focal plane. The advantages of the PAM are: high angular sensitivity, long-term stability character making angle monitoring over long time periods possible, high measurement accuracy in the order of sub-microradian, simultaneous measurement ability in two perpendicular directions or on two different objects, dynamic measurement possibility, insensitive to the vibration and air turbulence, automatic display, storage and analysis by use of the computer, small beam diameter making the alignment extremely easy and longer test distance. Some test examples are presented.

Previous analyses have shown that unconfined deflagrations propagating through both porous and nonporous energetic materials can exhibit a thermal/diffusive instability that corresponds to the onset of various oscillatory modes of combustion. For porous materials, two-phase-flow effects, associated with the motion of the gas products relative to the condensed material, play a significant role that can shift stability boundaries with respect to those associated with the nonporous problem. In the present work, additional significant effects are shown to be associated with confinement, which produces an overpressure in the burned-gas region that leads to reversal of the gas flow and hence partial permeation of the hot gases into the unburned porous material. This results in a superadiabatic effect that increases the combustion temperature and, consequently, the burning rate. Under the assumption of gas phase quasi-steadiness, an asymptotic model is presented that facilitates a perturbation analysis of both the basic solution, corresponding to a steadily propagating planar combustion wave, and its stability. The neutral stability boundaries collapse to the previous results in the absence of confinement, but different trends arising from the presence of the gas-permeation layer are predicted for the confined problem. Whereas two-phase-flow effects are generally destabilizing in the unconfined geometry, …

The results of a survey of organizational culture at a nuclear power plant are summarized and compared with those of a similar survey which has been described in the literature on ''high-reliability organizations''. A general-purpose cultural inventory showed a profile of organizational style similar to that reported in the literature; the factor structure for the styles was also similar to that of the plant previously described. A specialized scale designed to measure ''safety culture'' did not distinguished among groups within the organization that would be expected to differ.

The results of a survey of organizational culture at a nuclear power plant are summarized and compared with those of a similar survey which has been described in the literature on high-reliability organizations. A general-purpose cultural inventory showed a profile of organizational style similar to that reported in the literature; the factor structure for the styles was also similar to that of the plant previously described. A specialized scale designed to measure safety culture did not distinguish among groups within the organization that would be expected to differ.

The paper describes a model that visually portrays radiological survey performance as basic parameters (surveyor efficiency and criteria, duration of pause, and probe speed) are varied; field and laboratory tests provided typical parameter values. The model is used to illustrate how practical constraints on the time allotted to the task can affect radiological inspection performance. Similar analyses are applicable to a variety of other tasks (airport baggage inspection, and certain types of non-destructive testing) with similar characteristics and constraints.