A dynamic simulator of the TOPAZ II reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk, and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested and it is able to handle a step decrease of $8 worth of reactivity. It also provides simulations of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ II reactor system under both normal and casualty conditions.

Samples of chemically-vapor-deposited micrometer and sub-micrometer-thick films of polysilicon were analyzed by transmission electron microscopy (TEM) in cross-section and by Raman spectroscopy with illumination at their surface. TEM and Raman spectroscopy both find varying amounts of polycrystalline and amorphous silicon in the wafers. Raman spectra obtained using blue, green and red excitation wavelengths to vary the Raman sampling depth are compared with TEM cross-sections of these films. Films showing crystalline columnar structures in their TEM micrographs have Raman spectra with a band near 497 cm{sup {minus}1} in addition to the dominant polycrystalline silicon band (521 cm{sup {minus}1}). The TEM micrographs of these films have numerous faulted regions and fringes indicative of nanometer-scale silicon structures, which are believed to correspond to the 497cm{sup {minus}1} Raman band.

The Colorado economic impact study summarizes employment and economic benefits to the state from activities associated with the Uranium Mill Tailings Remedial Action (UMTRA) Project during Colorado state fiscal year (FY) 1993. To capture employment benefits, a questionnaire was distributed to subcontractor employees at the active UMTRA Project sites of Grand Junction, Rifle, and Gunnison, Colorado. An estimated 52 percent of the employees working on the UMTRA Project responded to this information request. Economic data were requested from each prime subcontractor, as well as from the Remedial Action Contractor. The most significant benefits associated with the UMTRA Project in Colorado are: Direct employment was estimated at 894 workers; An estimated 89 percent of all direct employment was local; Secondary employment resulting from remedial action at the active Colorado UMTRA Project sites and the Grand Junction vicinity property program is estimated at 546 workers. Total employment (direct and secondary) is estimated at 1440 workers for the period of study (July 1, 1992, to June 30, 1993). An estimated $24.1 million was paid in wages to UMTRA workers in Colorado during FY1993; Direct and secondary wage earnings were estimated at $39.9 million; Income tax payments to the state of Colorado were estimated …

Monitoring of swell continued on Coolside pilot plant run {number_sign}2 and FBC ash remolded near 95% of standard maximum dry density and optimum moisture content. Swell test also continued on non-hydrated FBC specimens as well as FBC pellets which were loosely placed in CBR molds. No significant deviations from previously reported patterns have been observed. Field and laboratory leaching studies have shown that the Coolside materials display low initial permeabilities which rapidly decrease upon addition of water. Where leaching was occurred the leachates are initially very high in sodium and chloride ions (10,000`s ppM) potassium and sulphate (1,000`s ppM), with lesser concentrations of molybdenum, boron, aluminum (10`s ppM), arsenic, selenium and vanadium (ppM) being detected. In some cases concentrations were shown to rapidly decrease by an order of magnitude within a few pore volume changes.

The kinetics of benzoate degradation by the anaerobic syntrophic bacterium, Syntrophus buswellii, in coculture with different sulfate reducers was studied with sulfate or nitrate as the electron acceptor. A threshold value for benzoate degradation dependent on the acetate concentration was observed with sulfate, but not nitrate, as the electron acceptor. No threshold was observed in tricultures containing an acetate-using sulfate reducer. The addition of the acetate-using sulfate reducer to cocultures that had degraded benzoate to its threshold value resulted in further degradation of benzoate to levels below the analytical detection limit (ca. 200 nM). These data are consistent with a thermodynamic explanation for the threshold, and exclude the possibility that the threshold was the result of the inhibitory action of the undissociated form of acetate.

Japan, as an issue, has entered the debate over U.S. approval of the North American Free Trade Agreement (NAFTA) in several ways. The Clinton Administration has argued that Americans should support NAFTA because if it fails to pass Congress, Japan will rush to negotiate a similar arrangement with Mexico. Proponents of NAFTA also have argued that since Japan opposes NAFTA (because of its presumed protectionism and the benefits it provides to North American businesses), it must be "good for America." Opponents of NAFTA argue that the agreement would provide opportunities for Japanese manufacturers to invest in Mexico and export unfettered to the American market. Also, they assert that NAFTA would be like previous trade agreements, particularly with Japan, that have ended up hurting the U.S. economy. In either case, the effects of NAFTA on Japan would likely be small.

The HRS Oil Shale Retort process consists of a pyrolysis section which converts kerogen of the shale to liquid and gaseous products, and a combustion section which burns residual carbon on the shale to heat the process. Average gas concentrations of selected gas phase species were determined from data measured at several placed on the combustion system of the Lawrence Livermore National Laboratory Hot-Recycled-Solids Retort Pilot Plant for representative rich and lean shale runs. The data was measured on-line and in real time by on-line meters (CO{sub 2}, CO, O{sub 2}), mass spectrometry (CO{sub 2}, O{sub 2}, H{sub 2}O, NO, CH{sub 4}, SO{sub 2}, N{sub 2} and Ar), and Fourier transform infrared spectroscopy (CO{sub 2}, CO, H{sub 2}O, NO, N{sub 2}O, NO{sub 2}, CH{sub 4}, SO{sub 2}, NH{sub 3}, and HCN). For both the rich and leans shale runs, the Lift-Pipe Combustor (LFT) exhibited gas concentrations (sampled at the exit of the LFT) indicative of incomplete combustion and oxidation; the Delayed-Fall Combustor (DFC) exhibited gas concentrations (sampled at the annulus and the exit of the DFC) indicative of much more complete combustion and oxidation. The Fluidized-Bed Combustor exhibited gas concentrations which were controlled to a large extent by the injection …

The authors report the first observation of optically pumped stimulated emission from an GaN epilayer at 77K and at room temperature grown by reactive ion-beam molecular beam epitaxy. The observed uv optical emission profile was a nonlinear function of the pump power density, with line narrowing at threshold power densities. The similarity in the emission profile as compared with those of films grown with low-pressure metal-organic chemical vapor deposition and metal-organic vapor phase epitaxy techniques will be noted.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and State and local governments on the following topics: Distillate fuel oil net production, imports and stocks on a US level and for all Petroleum Administration for Defense Districts (PADD) and product supplied on a US level; propane net production, imports and stocks on a US level and for PADD`s I, II, and III; natural gas supply and disposition and underground storage for the US and consumption for all PADD`S; as well as selected National average prices; residential and wholesale pricing data for heating oil and propane for those States participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the US and selected cities; and a 6--10 Day, 30-Day, and 90-Day outlook for temperature and precipitation and US total heating degree-days by city.

The evaluation of the accuracy, precision and lower detection limits of the determination of trace radionuclides in environmental samples can become quite sophisticated and time consuming. This in turn could add significant cost to the analyses being performed. In the present method, a {open_quotes}deficit reduction approach{close_quotes} has been taken to keep costs low, but at the same time provide defensible data. In order to measure the accuracy of a particular method, reference samples are measured over the time period that the actual samples are being analyzed. Using a Lotus spreadsheet, data are compiled and an average accuracy is computed. If pairs of reference samples are analyzed, then precision can also be evaluated from the duplicate data sets. The standard deviation can be calculated if the reference concentrations of the duplicates are all in the same general range. Laboratory blanks are used to estimate the lower detection limits. The lower detection limit is calculated as 4.65 times the standard deviation of a set of blank determinations made over a given period of time. A Lotus spreadsheet is again used to compile data and LDLs over different periods of time can be compared.

This brief report describes results pertaining to the development of insulated blocks. Areas covered include fabrication, noise and earthquake test design, and the development of a stuffing machine.

Conclusions: Release analyses of Pittsburgh No. 8 and Illinois No. 6 coals show that the {minus}28 mesh size fraction is fine enough to liberate ash and pyrite. Galvanic coupling with sacrificial anodes such as zinc, manganese and aluminum can effectively lower the potential of pyrite. This effect is more significant at pH 4.6 than at pH 9.2. The most negative pyrite potential is achieved when the surface area ratio of anode to pyrite is approximately 4:1. When coupled with pyrite at pH 9.2, the zinc anode exhibited unique potential vs time behavior which is different from that observed with manganese and aluminum. This is believed to be related to the build- up and break-down of zinc hydroxides on the surface. Voltammograms of pyrite at pH 9.2 and 4.6 demonstrated that pyrite surfaces can be significantly changed by galvanic coupling with sacrificial anodes. In flotation tests, metal powders were used as galvanic contactors to reduce the potential and depress pyrite. The potenial may be low enough to remove sulfur species from the surface. Stirred solutions are preferred for the removal of oxidized sulfur species by galvanic coupling; oxygen in solution must to be depleted prior to the addition of sacrificial anodes …

The recycle stream from the DWPF constitutes a major source of water addition to the High Level Waste evaporator system. As now designed, the entire flow of 3.5 to 6.5 gal/min (@ 25% and 75% attainment, respectively), or 2 gal/min during idling, flow to the 2H evaporator system (Tank 43). Substantial improvement in the HLW water balance and tank volume management is expected if the DWPF recycle to the HLW evaporator system can be significantly reduced. A task team has been appointed to study alternatives for reducing the flow to the HLW evaporator system and make recommendations for implementation and/or further study and evaluation. The brainstorming session detailed in this report was designed to produce the first cut options for the task team to further evaluate.

The Department of Energy has established specifications (Waste Acceptance Product Specifications for Vitrified High-Level Waste Forms, or WAPS) for canistered waste forms produced at Hanford, Savannah River, and West Valley. Compliance with these specifications requires that each waste form producer identify the items and activities which must be controlled to ensure compliance. As part of quality assurance oversight activities, reviewers have tried to compare the methodologies used by the waste form producers to identify items and activities important to waste form acceptance. Due to the lack of a documented comparison of the methods used by each producer, confusion has resulted over whether the methods being used are consistent. This confusion has been exacerbated by different systems of nomenclature used by each producer, and the different stages of development of each project. The waste form producers have met three times in the last two years, most recently on June 28, 1993, to exchange information on each producer`s program. These meetings have been sponsored by the Westinghouse GoCo HLW Vitrification Committee. This document is the result of this most recent exchange. It fills the need for a documented comparison of the methodologies used to identify items and activities important to waste form …

The method of moments is applied to precisely determine the mean values of three importance measures: risk reduction, partial derivative, and variance reduction. Variance reduction calculations, in particular, are significantly improved by eliminating the imprecision associated with Monte Carlo estimates. The three importance measures are extended to permit analyses of the relative importance of groups of basic and initiating events. The partial derivative importance measure is extended by assessing the contribution of a group of events to the gradient of the top event frequency. The group importance measures are quantified for the overall fuel damage equation and for 14 dominant accident sequences from an independent probabilistic safety assessment of the K Production Reactor. This application demonstrates both the utility and the versatility of the group importance measures.

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This Quality Assurance Program Plan (QAPP) provides the primary requirements for the integration of quality functions into all Technical Assistance Contractor (TAC) Project organization activities. The QAPP is the written directive authorized by the TAC Program Manager to accomplish this task and to implement procedures that provide the controls and sound management practices needed to ensure TAC contractual obligations are met. The QA program is designed to use monitoring, audit, and surveillance functions as management tools to ensure that all Project organization functions are executed in a manner that will protect public health and safety, promote the success of the Project, and meet or exceed contract requirements. The key to ensuring compliance with this directive is a two-step professional approach: utilize the quality system in all areas of activity, and generate a personal commitment from all personnel to provide quality service. The quality staff will be experienced, trained professionals capable of providing maximum flexibility to Project goal attainment. Such flexibility will enable the staff to be more cost effective and to further improve communication and coordination. To provide control details, this QAPP will be supplemented by approved standard operating procedures that provide requirements for performing the various TAC quality-related activities. …

Earthquake events are well-known to prams a variety of empirical scaling laws. Accordingly, renormalization methods offer some hope for understanding why earthquake statistics behave in a similar way over orders of magnitude of energy. We review the progress made in the use of renormalization methods in approaching the earthquake problem. In particular, earthquake events have been modeled by previous investigators as hierarchically organized bundles of fibers with equal load sharing. We consider by computational and analytic means the failure properties of such bundles of fibers, a problem that may be treated exactly by renormalization methods. We show, independent of the specific properties of an individual fiber, that the stress and time thresholds for failure of fiber bundles obey universal, albeit different, staling laws with respect to the size of the bundles. The application of these results to fracture processes in earthquake events and in engineering materials helps to provide insight into some of the observed patterns and scaling-in particular, the apparent weakening of earthquake faults and composite materials with respect to size, and the apparent emergence of relatively well-defined stresses and times when failure is seemingly assured.

The study of intermediate-energy heavy-ion nuclear reactions is reported. This work has two foci: the properties of nuclear matter under abnormal conditions, in this energy domain, predominately low densities and the study of the relevant reaction mechanisms. Nuclear matter properties, such as phase transitions, are reflected in the dynamics of the reactions. The process leads to an understanding of the reaction mechanism themselves and therefore to the response characteristics of finite, perhaps non-equilibrium, strongly interacting systems. The program has the following objectives: to study energy, mass, and angular momentum deposition by studying incomplete fusion reactions; to gain confidence in the understanding of how highly excited systems decompose by studying all emissions from the highly excited systems; to push these kinds of studies into the intermediate energy domain (where intermediate mass fragment emission is not improbable) with excitation function studies; and to learn about the dynamics of the decays using particle-particle correlations. The last effort focuses on simple systems, where definitive statements are possible. These avenues of research share a common theme, large complex fragment production. It is this feature, more than any other, which distinguishes the intermediate energy domain.

Tasks performed to develop an improved version of Advanced Cooling Technology`s Evaporative Subcooling System are described. Work on pump stability, improved drainage mechanism, and the American Refrigeration Institute engineering performance tests is presented.

We carried out essentially all the carbon cycle modeling calculations that were required by the IPCC Working Group 1. Specifically, IPCC required two types of calculations, namely, ``inverse calculations`` (input was CO{sub 2} concentrations and the output was CO{sub 2} emissions), and the ``forward calculations`` (input was CO{sub 2} emissions and output was CO{sub 2} concentrations). In particular, we have derived carbon dioxide concentrations and/or emissions for several scenarios using our coupled climate-carbon cycle modelling system.

During the past quarter, Tasks 3, 4, 5, and 6 were active. Task 3 Pilot Scale Combustion Testing activity included data analysis of pilot- and bench-scale combustion samples in support of the development of CQE slogging and fouling models. Under Task 4, field testing at the fifth host utility site -- New England Power Service Company`s Brayton Point Unit 3 -- was completed in March with the testing of the alternate coal. Test plans were finalized for the sixth and final field test to be performed at Brayton Point Unit 2 in April 1993. Tasks 5 and 6 activities were directed at design and development of CQE base classes and objects, continued formulation and integration of CQE algorithms and submodels, development of the user interface prototype, and preparation of the Fireside Advisor.

The L3 detector, located at the LEP storage ring at CERN (European Center for Nuclear Research), has recently installed a silicon microvertex detector (SMD). The purpose of the SMD is to enhance the tracking capabilities of L3 and to provide increased vertex measurement precision for tagging b-jets in the search for the Higgs boson, when LEP doubles its center of mass energy for the LEP 200 running. The subject of this article is the fabrication and testing of the front-end electronics for the SMD. The article is organized into several sections. The first section describes the SMD, the second section discusses the front-end electronics, the third section presents the testing procedures and the results of the tests.