Energy Technology Data Exchange (ETDEWEB)

This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period October 1, 2004 through December 31, 2004. The following tasks have been completed. First, the renovation of the new Combustion Laboratory and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building have proceeded well. Second, the detailed design of supporting and hanging structures for the CFBC was completed. Third, the laboratory-scale simulated fluidized-bed facility was modified after completing a series of pretests. The two problems identified during the pretest were solved. Fourth, the carbonization of chicken waste and coal was investigated in a tube furnace and a Thermogravimetric Analyzer (TGA). The experimental results from this study are presented in ...

Energy Technology Data Exchange (ETDEWEB)

This work develops and demonstrates a laboratory-scale high temperature natural gas furnace that can operate with/without oxygen enrichment to significantly improve energy efficiency and reduce emissions. The laboratory-scale is 5ft in diameter & 8ft tall. This furnace was constructed and tested. This report demonstrates the efficiency and pollutant prevention capabilities of this test furnace. The project also developed optical detection technology to control the furnace output.

British Library Electronic Table of Contents (United Kingdom)

A laboratory-scale multi-layer system was developed for the adsorption of PCDD/Fs from gas streams at various operating conditions, including gas flow rate, operating temperature and water vapor content. Excellent PCDD/F removal efficiency (>99.99%) was achieved with the multi-layer design with bead-shaped activated carbons (BACs). The PCDD/F removal efficiency achieved with the first layer adsorption bed decreased as the gas flow rate was increased due to the decrease of the gas retention time. The PCDD/F concentrations measured at the outlet of the third layer adsorption bed were all lower than 0.1ng I-TEQNm-3. The PCDD/Fs desorbed from BAC were mainly lowly chlorinated congeners and the PCDD/F outlet concentrations increased as the operating temperature was increased. In addition, the r...

Energy Technology Data Exchange (ETDEWEB)

''Intelligent Extruder'' described in this report is a software system and associated support services for monitoring and control of compounding extruders to improve material quality, reduce waste and energy use, with minimal addition of new sensors or changes to the factory floor system components. Emphasis is on process improvements to the mixing, melting and de-volatilization of base resins, fillers, pigments, fire retardants and other additives in the :finishing'' stage of high value added engineering polymer materials. While GE Plastics materials were used for experimental studies throughout the program, the concepts and principles are broadly applicable to other manufacturers materials. The project involved a joint collaboration among GE Global Research, GE Industrial Systems and Coperion Werner & Pleiderer, USA, a major manufacturer of compounding equipment. ...

International Nuclear Information System (INIS)

Model construction of the laboratory scale superconducting fault current limiter circuit (SFCL) has been performed. The SFCL is fault current limiter and used as electric network security. It mainly consists of a copper coil, a superconducting ring and an iron core that are concentrically arranged. The SFCL circuit is essentially a transformer where the secondary windings are being replaced by the ring of YBa_2Cu_3O_7_-_x superconductor (HTS). The ring has critical transition temperature Tc = 92 K and critical current Ic = 3.61 A. Characterization of the SFCL circuit is simulated by ANSYS version 5.4 software. The SFCL circuit consists of load and transformer impedances. The results show that the inductions of magnet field flux in the iron core of primer windings and ring disappear to one other before fault state. It means that impedance of the transformer is zero. After the condition a superconductivity behavior of the ...

Science.gov (United States)

A laboratory-scale well-mixed thermostatic reactor with continuously blasting air was used to investigate the oxidation inhibition of sulfite in dual alkali flue gas desulfurization (FGD) system. The effects of operating parameters such as pH value and catalyst concentration on the oxidation were studied. Sodium thiosulfate was used in the system, and was found that it significantly inhabited the sulfite oxidation. In the absence of catalyst, sodium thiosulfate at 12.67 mmol/L had an inhibition efficiency of approximately 98%. While in the presence of catalyst, sodium thiosulfate at 26.72 mmol/L had an inhibition efficiency less than 85.0%. The oxidation reaction order of sulfite in the sodium thiosulfate was determined to be -1.90 and -0.55 in the absence and presence of the catalyst, respectively. Apparent activation energy of oxidation inhibition was calculated to be 53.9 kJ/mol. Pilot tests showed that the consumption ...

International Nuclear Information System (INIS)

A preliminary investigation was conducted on ion specific membranes. This investigation concentrated on testing candidate organic compounds for transporting cesium ions through a membrane composed of the organic compound supported on a substrate. Solid PVC membranes were initially tried, but were found to be too slow. Thereafter, only liquid membranes were tested. These were faster and cesium concentration factors up to 2.96 were achieved in a single membrane cell. A cell with two membranes achieved a cesium concentration factor of 4.19. Cesium precipitation with sodium tetraphenyl borate in high sodium concentrations was explored. No interference from sodium was found until the sodium nitrite concentration reached 4.5 moles. Concurrently, cesium concentrations as high as 5.4 g/L were precipitated. Potassium tetraphenyl borate is being investigated for use in exchange columns for the removal of cesium from solutions. Initial investigations show that cesium removal is affected by [K"+] ...

Energy Technology Data Exchange (ETDEWEB)

Lean premixed combustion (LPC) of natural gas is of considerable interest in land-based gas turbines for power generation. However, modeling such combustors and adequately addressing the concerns of LPC, which include emissions of nitrogen oxides, carbon monoxide and unburned hydrocarbons, remains a significant challenge. In this paper, characteristics of published simulations of gas turbine combustion are summarised and methods of modeling turbulent combustion are reviewed. The velocity-composition PDF method is selected for implementation in a new comprehensive model that uses an unstructured-grid flow solver. Reduced mechanisms for methane combustion are evaluated in a partially stirred reactor model. Comprehensive model predictions of swirl-stabilised LPC of natural gas are compared with detailed measurements obtained in a laboratory-scale combustor. The model is also applied to industrial combustor geometries. (Author)

Energy Technology Data Exchange (ETDEWEB)

The rates of hydrogen release from simulated high-level liquid waste (SHLLW) during irradiation of {sup 60}Co {gamma}-rays have been studied using a laboratory-scale apparatus. The SHLLW used was made up of 28 different metal elements, the concentrations of which were determined from a computed data (ORIGEN-2) for a Purex spent fuel (burn-up of 4.5 GWd/t, cooling time of 4 years) except for those of corrosion products (Fe, Cr and Ni) and of chemical process additive (P). The nitrate ion concentration of the SHLLW was 4.97 M. The G-value of hydrogen release was 0.0164 for stirred conditions, but for nonstirred conditions with dose rate : 2.8 kGy/h and with the SHLLW solution height more than 8 cm, the following relation was found between the G-value and the solution height (d cm); G(H{sub 2}) = 0.100 d{sup -1.6}. The G-values of oxygen and nitrogen releases were also determined. (author)

Energy Technology Data Exchange (ETDEWEB)

Plans for the disposal of radioactive liquid and solid wastes presently stored in double-shell tanks at the Hanford Site call for retrieval and processing of the waste to create forms suitable for permanent disposal. Waste will be retrieved from a tank using a submerged slurry pump in conjunction with one or more rotating slurry jet mixer pumps. Pacific Northwest Laboratory (PNL) has conducted tests using simulated waste slurries to assess the effects of a impinging slurry jet on the corrosion rate of the tank wall and floor, an action that could potentially compromise the tank's structural integrity. Corrosion processes were investigated on a laboratory scale with a simulated neutralized cladding removal waste (NCRW) slurry and in a subsequent test with simulated neutralized current acid waste (NCAW) slurry. The test slurries simulated the actual NCRW ...

Energy Technology Data Exchange (ETDEWEB)

This study aims to develop a particulate model combining solid waste particle combustion and heavy metal vaporization from burning particles during MSW incineration in a fluidized bed. The original approach for this model combines an asymptotic combustion model for the carbonaceous solid combustion and a shrinking core model to describe the heavy metal vaporization. A parametric study is presented. The global metal vaporization process is strongly influenced by temperature. Internal mass transfer controls the metal vaporization rate at low temperatures. At high temperatures, the chemical reactions associated with particle combustion control the metal vaporization rate. A comparison between the simulation results and experimental data obtained with a laboratory-scale fluid bed incinerator and Cd-spiked particles shows that the heavy metal vaporization is correctly predicted by the model. The predictions are better at higher temperatures because ...

Energy Technology Data Exchange (ETDEWEB)

One of the design targets for the ITER Tokamak Exhaust Processing system is not to lose more than 10{sup -5} g h{sup -1} into the Normal Vent Detritiation System of the Tritium Plant. The plasma exhaust gas, therefore, needs to be processed in a way that an overall tritium removal efficiency of about 10{sup 8} is reached. Such a high decontamination factor can only be achieved by multistage processes. The third step of the three step CAPER process developed at the TLK is based on a so-called permeator catalyst (PERMCAT) reactor, a direct combination of a Pd/Ag permeation membrane and a catalyst bed. The PERMCAT principle is based on isotopic swamping in a counter current mode. Previous tritium experiments employing laboratory scale PERMCAT reactors have revealed decontamination factors as high as 10{sup 5} for the third CAPER step. First tritium tests with a technical scale PERMCAT reactor led to ...

British Library Electronic Table of Contents (United Kingdom)

Solid-state fermentation of soybean hulls supplemented with wheat bran using a co-culture of Trichoderma reesei and Aspergillus oryzae was performed. Three parameters - initial moisture content, incubation temperature, and initial pH - were optimized in culture flasks using response surface methodology. Parameter optimization was carried out with respect to filter paper activity and b-glucosidase activity in the culture. Temperature of 30^oC, pH of 5, and moisture content of 70% were found to be optimum. Optimized parameters were used for laboratory scale-up in static tray fermenters. The maximum filter paper activity of 10.7FPU/g-ds and b-glucosidase of 10.7IU/g-ds were obtained after 96-h incubation period in static tray fermenters in agreement with optimized activities at shake flask le...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this project was to investigate the origin of pressure fluctuations in fluidized bed systems. The study assessed the potential for using pressure fluctuations as an indicator of fluidized bed hydrodynamics in both laboratory scale cold-models and industrial scale boilers. Both bubbling fluidized beds and circulating fluidized beds were evaluated. Testing including both cold-flow models and laboratory and industrial-scale combustors operating at elevated temperatures. The study yielded several conclusions on the relationship of pressure fluctuations and hydrodynamic behavior in fluidized beds. The study revealed the importance of collecting sufficiently long data sets to capture low frequency (on the order of 1 Hz) pressure phenomena in fluidized beds. Past research has tended toward truncated data sets collected with high frequency response transducers, which miss much of the spectral structure of fluidized ...

Science.gov (United States)

... Hydropower analysis may include run-of-river, peaking, and pumped storage plants as well as system power operation. ...

Energy Technology Data Exchange (ETDEWEB)

Recent research at the laboratory scale by a number of organizations in different countries has shown that with the use of particular types of solvents it is possible to achieve almost complete conversion of coal to liquid products under relatively mild process conditions. This work is reviewed and the conclusions to be drawn from it are summarized.

International Nuclear Information System (INIS)

The full scope simulator in Daya Bay Nuclear Power Station is imported from THOMSON-CSF company in France. It is a large facility, using digital simulation technology, that simulate the main control room of Daya Bay Nuclear Power Station with the high fidelity. It is used for training operators; system analyzing including operation procedure verification. The input output interface system of the simulator is the bridge of the information exchange between instrumentation and the computer. From the point of view of data transfer, this paper discusses the operation principle of the I/O interface system.

International Nuclear Information System (INIS)

An effective procedure for removing _3H, Xe and Kr from irradiated fuels was demonstrated using Shippingport UO"2 fuel. The release characteristics of _3H, Kr, Xe, and I from irradiated nuclear fuel have been determined as a function of temperature and gaseous environment. Vacuum outgassing and a flowing gas stream have been used to vary the gaseous environment. Vacuum outgassing released about 99% of the _3H and 20% of both Kr and Xe within a 3 h at 1500_0C. Similar results were obtained using a carrier gas of He containing 6% H"2. However, a carrier gas containing only He resulted in the release of approximately 80% of the _3H and 99% of both Kr and Xe. These results indicate that the release of these volatile fission products from irradiated nuclear fuel is a function of the chemical composition of the gaseous environment. The rate of tritium release increased with increasing temperature (1100 to 1500_0C) and with the addition of hydrogen to the gas stream. Using crushed UO"2 fuel ...

Energy Technology Data Exchange (ETDEWEB)

This is the first time that the adsorption of binary mixtures of polycyclic aromatic hydrocarbons (PAHs) has been studied. This study was carried out at laboratory scale in an experimental apparatus specially designed for this aim: with gas-phase fluorescence, a new detection procedure was used. Experimental conditions, mainly in terms of temperature (150C) and contaminant concentration (approximately 1 ppmv), close to the ones observed in energy generation systems, were applied. The PAH adsorption process interpretation was carried out by recording the experimentally obtained breakthrough curves. After the detection parameter optimization, the influence of adsorbate characteristics in the hot gas cleaning of PAH was studied. In this system, the adsorption of 10 binary mixtures of five PAH (naphthalene (Np), fluorene (Fu), phenanthrene (Phe), fluoranthene (Fl), and pyrene (Py)) on an activated carbon ...

International Nuclear Information System (INIS)

The authors review two types of simulators for the analysis of cosmic ray neutron-induced soft errors (SE's). One of them is the neutron-induced soft error simulator (NISES). A recently proposed nuclear reaction theory forms the foundation for the nuclear reaction database used in NISES. The other simulator, the simplified simulator MBGR, is based on a modified version of the burst generation rate (BGR) model. Both simulators accurately simulate neutron-induced SE rates (SER's). MBGR actually provides an easier and quicker estimation of neutron-induced SER's than NISES. On the other hand, NISES covers more applications; it simulates neutron-induced charge collection, multiple-bit SE, and #alpha#-induced SE analysis

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

This paper describes TENT, a system designed for integrating the various tools and parts of a CFD simulation system (CFD - Computational Fluid Dynamics) and the simulation code itself in one interactive simulation environment. Initially the system was intended to be a TEstbed for Numerical Turbine simulation but it turned out that the approach was general enough to be suitable for more complex simulation tasks in the field of aircraft simulation. The paper will give a brief description of a CFD simulation system and its component interactions, which are the basis for describing the Component Architecture based on CORBA. This includes the control architecture using an event model and data flow considerations. Because most CFD codes use parallelization ...

Energy Technology Data Exchange (ETDEWEB)

Co-combustion of chicken litter with coal was performed in a laboratory-scale fluidized bed combustor to investigate the effect of chicken litter addition on the partitioning behavior of mercury. Gaseous total and elemental mercury concentrations in the flue gas were measured online, and ash was analyzed for particle-bound mercury along with other elemental and surface properties. The mercury mass balance was between 85 and 105%. The experimental results show that co-combustion of chicken litter decreases the amount of elemental and total mercury in the gas phase. Mercury content in fly ash increases with an increasing chicken litter share. 22 refs., 6 figs., 5 tabs.

International Nuclear Information System (INIS)

A reliable inventory control system was developed at the Fast Flux Test Facility (FFTF) to keep track of the occupancy of 900 refueling facility locations, to compile historical data on the movement of each reactor assembly, and to simulate assembly moves. The simulate capability is valuable because it allows verification of documents before they are issued for use in the plant, and eliminates the possibility of planning illegal or impossible moves. The system is installed on a UNIVAC 1100 computer and is maintained using a data base management system by Sperry Univac called MAPPER.

CERN Document Server

We have carried out numerical simulations of strongly gravitating systems based on the Einstein equations coupled to the relativistic hydrodynamic equations using adaptive mesh refinement (AMR) techniques. AMR coalescences of neutron stars can now be simulated with sufficient resolution covering the neutron stars while having the computational domain extend to the local wave zone. We show an AMR simulation carried out with a workstation having an accuracy equivalent to that of a 1025^3 regular uni-grid simulation, which is, to the best of our knowledge, larger than all previous simulations of similar NS systems on supercomputers. We believe the capability opens new possibilities in general relativistic simulations.

Energy Technology Data Exchange (ETDEWEB)

Carbon Black and activated carbon materials providing high surface areas and a distinct pore distribution are prime materials for supercapacitor applications at frequencies < 0.5 Hz. A number of these materials were tested for their specific capacitance, surface and pore size distribution. High capacitance electrodes were manufactured on the laboratory scale with attention to ease of processability. (author) 1 fig., 1 ref.

Energy Technology Data Exchange (ETDEWEB)

Energy from biomass is a CO{sub 2} neutral, sustainable form of energy. Anaerobic digestion is an established technology for converting biomass to biogas, which contains around 60% methane, besides CO{sub 2} and various contaminants. Most types of biomass contain material that cannot be digested; in woody biomass, this portion is particularly high. Therefore, conventional anaerobic digestion is not suited for the production of biogas from woody biomass. While wood is already being converted to energy by conventional thermal methods (gasification with subsequent methanation), dung, manure, and sewage sludge represent types of biomass whose energy potential remains largely untapped (present energetic use of manure in Switzerland: 0.4%). Conventional gas phase processes suffer from a low efficiency due to the high water content of the feed (enthalpy of vaporization). An alternative technology is the hydrothermal gasification: the water contained within the biomass serves as reaction ...

Energy Technology Data Exchange (ETDEWEB)

This paper proposes the design of LQ-PSS (linear quadratic power system stabilizer) for improving power system stability using genetic algorithm(GA). We are turned weighting matrices of LQ-PSS using GA. To evaluate the usefulness of the proposed method, we performed the nonlinear simulation on a single machine infinite system. As results on a single machine infinite system. As results of the simulation, the proposed method shows the better control performance than CPSS(conventional power system stabilizer) in terms of settling time and damping effects. (author). 7 refs., 7 figs., 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

This revised edition discusses a large number of renewable energy systems. Future trends are outlined. Economic efficiency calculations are explained and analyzed. Many exemplary calculations and graphical representations illustrate the various technologies and methods of calculation. This standard book addresses university students, scientists and engineers in research and industry. The accompanying DVD is one of the most extensive compilations of demo programs and full versions for simulation of renewable energy systems, all illustrations of the book in electronic format, additional text and a user-friendly navigation aid. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Stochastic models for the simulation of global radiation are discussed. Thermal transients in the ground are analyzed. The performance of buried-pipe storage and a space heating system with long-term storage is described.

Science.gov (United States)

... which may have embedded remote terminals, and (4 ... model the time-variant or stochastic aspects of ... on such system parameters as queue size, time ...

International Nuclear Information System (INIS)

This report describes accomplishment of simulations of Pyrochemical Process Operation by using virtual engineering models. The pyrochemical process using molten salt electrorefining would introduce new technologies for new fuels of particle oxide, particle nitride and metallic fuels. This system is a batch treatment system of reprocessing and re-fabrication, which transports products of solid form from a process to next process. As a results, this system needs automated transport system for process operations by robotics. In this study, a simulation code system has been prepared, which provides virtual engineering environment to evaluate the pyrochemical process operation of a batch treatment system using handling robots. And the simulation study has been conducted to evaluate the required ...

Science.gov (United States)

A previous paper introduced the use of wave digital filters as a basic building block for power system simulation, particularly suitable for real-time applications. This paper stresses the simulation of non-linear and switching elements, emphasizing the advantages of the wave filters implementation. The digital structure is maintained even when non-linear components change their characteristics or power electronic devices switch their states. As a very important by-product, the suppression of numerical oscillations related to the trapezoidal rule is achieved in a rather simple way, with no effects on simulation results.

Energy Technology Data Exchange (ETDEWEB)

The paper presents a sequential procedure for coordinated stabilization of a multimachine power system with arbitrary complexity of the system model. The most effective machine to be equipped with a power system stabilizer is identified using eigenvalue analysis. The selection is based on the sensitivity of critical eigenvalues to increases in the coefficient of a damping term which is inserted in each equation of motion, in succession. The method is applied to a three-machine system and simulation studies show appreciable improvements in the small disturbance stability of the system.

International Nuclear Information System (INIS)

Accurate modeling of system response and scatter distribution is crucial for image reconstruction in emission tomography. Monte Carlo simulations are very well suited to calculate these quantities. However, Monte Carlo simulations are also slow and many simulated counts are needed to provide a sufficiently exact estimate of the detection probabilities. In order to overcome these problems, we propose to split the simulation into two parts, the detection system and the object to be imaged (the patient). A so-called 'virtual boundary' that separates these two parts is introduced. Within the patient, particles are simulated conventionally. Whenever a photon reaches the virtual boundary, its detection probability is calculated analytically by evaluating a multi-dimensional B-spline that depends on the photon position, direction and energy. The ...

International Nuclear Information System (INIS)

A nuclear power plant engineering (NPP) simulator may include many system functions such as thermal-hydraulic calculation, 3D reactor neutron kinetics model, control and protection system, display and operational human-machine interface, intelligent alarm system, etc. If all those functions are simulated using a single code, the size of the program will cause structural or managerial problems, and the hardware requirement could be tremendous. Thus, any local function errors or changes may affect the whole code, which will make development and maintenance extremely costly. So the nondistributed code is not considered to be flexible and feasible. Currently, distributed and parallel technologies have been applied to develop NPPs engineering simulator for safety analysis, verification of advanced main control room display, operation and intelligent alarm design. The ...

Energy Technology Data Exchange (ETDEWEB)

A study of the joint evolution of the normal- and neutron-star components of massive binaries opens with a classification scheme and the analytic expressions to be applied in Paper II for computer simulation of the observable properties of such systems.

CERN Document Server

We examine the observable properties of simulated barred galaxies including radial mass profiles, edge-on structure and kinematics, bar lengths and pattern speed evolution for detailed comparison to real systems. We have run several simulations in which bars are created through inherent instabilities in self-consistent simulations of a realistic disc+halo galaxy model with a disc-dominated, flat rotation curve. These simulations were run at high (N=20M particles) and low (N=500K) resolution to test numerical convergence. We determine the pattern speeds in simulations directly from the phase angle of the bar versus time and the Tremaine-Weinberg method. Fundamental dynamics do not change between the high and low resolution, suggesting that convergence has been reached in this case. We find the higher resolution is needed to simulate ...

Energy Technology Data Exchange (ETDEWEB)

A detailed component-based simulation model of a geothermal heat pump system has been calibrated to monitored data taken from a family housing unit located at Fort Polk, Louisiana. The simulation model represents the housing unit, geothermal heat pump, ground heat exchanger, thermostat, blower, and ground-loop pump. Each of these component models was 'tuned' to better match the measured data from the site. These tuned models were then interconnect to form the system model. The system model was then exercised in order to demonatrate its capabilities.

Energy Technology Data Exchange (ETDEWEB)

In this paper, we have designed power system stabilizer (PSS) using object-oriented method. There are several types of power system stabilizer, A proportional-integral (PI) controller is very simple for practical implementation. Therefore it has been widely employed by the industry. The methods of obtaining the gains (Ki,Kp) of PI controller are root-locus method and sub-optimal regulator approach. But these methods are cannot be applicable to nonlinear system and faulted power system. So we proposed a new method which can be applied to nonlinear system by numerical analysis method. The method of dynamic system simulation by numerical method is very difficult and complex. We proposed flexible simulation method for complex power system analysis using object-oriented programming (OOP) and applied to PI ...

Energy Technology Data Exchange (ETDEWEB)

Dynamic stability improvement of a longitudinal power system using a power system stabilizer (PSS) and a static VAR compensator (SVC) is reported in this paper. An analytical approach is developed for the determination of PSS parameters. Results from time domain simulations indicate that the PSS and the SVC are very effective in damping system oscillations.

British Library Electronic Table of Contents (United Kingdom)

This project is about the simulation design of an engine control unit (ECU) for an Otto cycle engine with electronic fuel injection (EFI). The simulation includes a model for the ECU as well as physical parameters of the engine, which allows closed-loop control and monitoring of various systems.This simulation has been realized using Simulink and Stateflow, which are components of Mathworks' MATLAB software.The program allows control of various parameters of the ECU, as well as the simulation of failures to verify that the designed ECU is fault-tolerant and can control the engine using an open loop control. The main function the ECU provides is fuel metering.Subsequently, this program could be used as a tool to quickly develop and test models of ECU in order to control an engine in laborat...

International Nuclear Information System (INIS)

An alkaline-side solvent extraction process was developed for cesium removal from Savannah River Site (SRS) tank waste. The process was invented at Oak Ridge National Laboratory and developed and tested at Argonne National Laboratory using singlestage and multistage tests in a laboratory-scale centrifugal contactor. The dispersion number, hydraulic performance, stage efficiency, and general operability of the process flowsheet were determined. Based on these tests, further solvent development work was done. The final solvent formulation appears to be an excellent candidate for removing cesium from SRS tank waste.

Energy Technology Data Exchange (ETDEWEB)

By means of an analogous simulator, which can simulate a power supply system, a method to determine the transfer function of a Power System Stabilizer (PSS) is developed. The purpose of the PSS is to damp unwanted electro-mechanical oscillations. The method is very systematic and there is no need for specified values of the parameters used in the system. It is assumed that the power generator system is linear for small variations. The system can be considered to be a black box. Measurements executed by means of this method are completely controlled by the person who enforces the measurement. By applying this method carefully, irregularities are almost out of the question. The equipment necessary are a PC with two AD-ports and an adjustable sinus-generator. A comparison is made with a more traditional method, in which a spectrum analyzer is ...

Energy Technology Data Exchange (ETDEWEB)

This report illustrates how, thanks to the development of a new algorithm for the probabilistic evaluation in a given period (e.g. one week) of the operating costs and risk indices (reliability) of a generation system with energy-constrained units, it has been possible to significantly improve the WAT program, used for many years by ENEL for generation expansion planning studies. In particular, it describes how the annual simulation of the system operation is accomplished, so as to calculate the mean expected values of the yearly operating costs (fuel) and the risk indices, at the same time optimizing the use of hydro resources and pumped-storage plants. (author).

Energy Technology Data Exchange (ETDEWEB)

This paper deals with dynamic study of co-generator system with derived dynamic models of generator, excitation system, and turbine/governor from field tests. Mainly this study concentrates on frequency control by under-frequency relay. We simulates dynamic study of co-generator system using EMTDC. (author). 4 refs., 13 figs., 4 tabs.

Energy Technology Data Exchange (ETDEWEB)

The performance of bunch-feedback systems based on two-tap FIR filters is discussed, particularly for transverse cases. Since they are the simplest type of FIR digital filters, the two-tap FIR filters should be suited to systems that require a very fast processing speed. However, in these feedback systems, a bunch must turn along a ring several times from the position-measurement to feedback kicking. Within these turns, irregular phase-jumps in the betatron motion can occur, due to several causes, such as the wake forces and beam-beam force. The discussion given in this paper is focussed on the effect of beam-beam collisions on these feedback systems. Based on linear theory and simulation studies, it has been found that these feedback systems can work with good performance, even under the influence of a strong beam-beam force. (author)

International Nuclear Information System (INIS)

Experience with the identification and tuning of exciter constants for a generating unit as the Second Nuclear Power Plant of Taiwan Power Company is reported. Field test is first performed on the excitation system with the generator open-circuited. Since the field test results differ from the computer simulation results using manufacturer's constants, the authors first modify the manufacturer's constants based on their previous experience to reach a preliminary set of parameters for the excitation system. Then a hybrid nonlinear simulation-sensitivity matrix method is developed to further refine the excitation system parameters. The exciter constants are tuned in order to give better dynamic response before a power system stabilizer is applied to the generator. Field tests are then performed in order to compare the dynamic response of the generator without and ...

Energy Technology Data Exchange (ETDEWEB)

The present paper is concerned with the prediction method for the motions and tensions of mooring lines on slack-moored floating oceanic architectural building in coastal zone. The motions and the tensions of mooring lines were estimated by the time domain numerical simulation in the present method. The present method includes the nonlinearity of mooring system, slow varying wave drift force. The authors performed a time domain numerical simulation for motions and the tensions of mooring lines on floating barge in two component waves. Also, the results obtained by numerical simulation were compared with the experimental results. The validity of the present method was confirmed.

International Nuclear Information System (INIS)

It has been issued that ROP(Regional Overpower Protection) for Wolsong Unit 1 needed to be reanalyzed due to the aging effect. Thermo-hydraulics and core simulation have to be performed for calculation of the fuel bundle power, channel power and detector signal production. PPV/MULTICELL/RFSP code system was used to calculate the power distribution for the ROP analysis. In this study, 232 cases out of 926 scenarios which include postulated accidents such as Startup after Short Shutdown, Shim Cases, Stepback, Insertion and Withdrawal of Reactivity Control Rods were simulated.

Science.gov (United States)

The understanding of transport processes that occur in naturally fractured geothermal systems is far from being complete. Often, evaluation and numerical simulations of fractured geothermal reservoirs, are carried out by assuming equivalent porous media and homogeneous petrophysical properties within big matrix blocks. The purpose of this paper, is to present a comparison between results obtained from numerical studies of a naturally fractured reservoir treated as a simple porous medium and the simulation of some real aspects of the fractured reservoir. A general conclusion outlines the great practical importance of considering even approximately, the true nature of such systems. Our results show that the homogeneous simplified evaluation of the energy resource in a fractured system, could result in unrealistic estimates of the reservoir capacity to generate ...

British Library Electronic Table of Contents (United Kingdom)

Thin films of Ni and Ni alloy have been widely used in microelectromechanical systems (MEMS) and magnetic storage systems. As the dimensions of components in these systems decrease to the micro-scale, even the nano-scale, the interfacial phenomena significantly differ to the counterparts on the macro-scale. A better understanding of micro-/nano-tribology will benefit the fabrication of the small components. In this manuscript parallel molecular dynamics (MD) simulations have been conducted to investigate the nanoscratch behavior of nickel. The simulations are performed for two cases with different indenter shapes. Case I has a sharp indenter, while the indenter in Case II is blunt. It has been found that the indenter shape significantly influences the nanoscratch deformation. The sharp ind...

Energy Technology Data Exchange (ETDEWEB)

The U.S. Department of Energy (DOE) is interested in developing tools and methods for potential U.S. use in designing and evaluating safeguards systems. For this goal several DOE National Laboratories are defining the characteristics of typical facilities of several size scales, and the safeguards measures and instrumentation that could be applied. Lawrence Livermore National Laboratory is providing systems modeling and analysis of facility and safeguards operations, diversion path generation, and safeguards system effectiveness. The constituent elements of diversion scenarios are structured using directed graphs (digraphs) and fault trees. Safeguards indicator probabilities are based on sampling statistics and/or measurement accuracies. Scenarios are ranked based on value and quantity of material removed and the estimated probability of non-detection. Significant scenarios, especially those involving timeliness or randomly ...

Energy Technology Data Exchange (ETDEWEB)

A complete analysis is performed to simulate biomass production incorporated into a realistic whole farm situation, including or replacing a typical crop mix. Representative farms are constructed to accommodate such simulation. Four management systems are simulated for each firm, with each simulation depicting a different crop mix and/or use of different farming technologies and production methods. The first simulation was a base farm plan in which the operator would maintain the historical crop mix for the area, participate in all price support programs, and not participate in either a conservative reserve or a biomass production program. In the second simulation, the operator would again maintain the historical crop mix, would not participate in a conservation reserve or biomass production program, and would be ineligible to participate in ...

Science.gov (United States)

Symplectic integrators designed for simulating soft matter at constant temperature and constant pressure (or constant surface tension) are presented. In addition to the well-known merits of symplectic integrators, such as long time stability, these methods allow the estimation of thermal heat production/absorption and thus entropy differences through a simple function of the time scaling factor ?. The relative entropy estimation around crystal-liquid phase transition is given for systems with soft core repulsive potential.

Energy Technology Data Exchange (ETDEWEB)

The paper deals with a model in which the motion of a gas in plasma accerators and high-curent discharges in the present of a skin effect is treated as expulsion by a 'magnetic piston' under the action of surface current flow. Specifically examined is the situation where the initial gas pressure is negligible in comparison with the magnetic pressure, and the motion of the gas may be treated as a self-simulating one. A system of hydrodynamic equations of the problem is derived and integrated by Adam's method. Results are plotted and discussed.

Energy Technology Data Exchange (ETDEWEB)

We report on the software aspects of the development of a switch-based data acquisition system at Fermilab. This paper describes how, with the goal of providing an integrated systems engineering'' environment, several powerful software tools were put in place to facilitate extensive exploration of all aspects of the design. These tools include a simulation package, graphics package and an Expert System shell which have been integrated to provide an environment which encourages the close interaction of hardware and software engineers. This paper includes a description of the simulation, user interface, embedded software, remote procedure calls, and diagnostic software which together have enabled us to provide real-time control and monitoring of a working prototype switch-based data acquisition (DAQ) system.

British Library Electronic Table of Contents (United Kingdom)

A model for risk and reliability analysis of complex multifunctional production process systems is presented. The model employs Monte-Carlo and Markov Chain algorithms that uses a weighted index to train and simulate the fuzzy hazard data sets which represents failure outcomes of risk component transient and non-transient systems. Early simulation results shows that hazard rates and the risk of containment loss from typical floating production and storage offloading (FPSO)-Riser system for the risk components in parallel or series increases exponentially with time and decreases as safety ratings fraction increases. The reliability value decreases with time and safety fraction (SFAC) for all fuzzy hazard classifications. The results of the computed mean time before repair (MTBR) show that t...

CERN Document Server

We consider dimensional reduction techniques for the Liouville-von Neumann equation for the evaluation of the expectation values in a mixed quantum system. In applications such as nuclear spin dynamics the main goal for simulations is being able to simulate a system with as many spins as possible, for this reason it is very important to have an efficient method that scales well with respect to particle numbers. We describe several existing methods that have appeared in the literature, pointing out their limitations particularly in the setting of large systems. We introduce a method for direct computation of expectations via Chebyshev polynomials (DEC) based on evaluation of a trace formula combined with expansion in modified Chebyshev polynomials. This reduction is highly efficient and does not destroy any information. We demonstrate the practical application of the scheme for a ...

Energy Technology Data Exchange (ETDEWEB)

In this book are found technical and scientific papers on the main works of the Direction of the Fuel Cycle (DCC) in France. The study fields are: the up-side of the nuclear fuel cycle with theoretical studies (plasma simulation) and technological developments and instrumentation (lasers diodes, carbides plasma projection, carbon 13 enrichment); the down-side nuclear fuel cycle with theoretical studies (ion Eu{sup 3+} complexation simulation, decay simulation, uranium and plutonium diffusion study, electrolyser operating simulation), scenario studies ( recycling, wastes management), experimental studies; dismantling and cleaning (soils cleaning, surface-active agent for decontamination, fault tree analysis); analysis with expert systems and mass spectrometry. (A.L.B.)

Energy Technology Data Exchange (ETDEWEB)

A non-dissipative drift kinetic simulation scheme, which rigorously satisfies the time-reversibility, is applied to the three-mode coupling problem of the ion temperature gradient (ITG) instability. It is found from the simulation that the three-mode ITG system repeats growth and decay with a period which shows a logarithmic divergence for infinitesimal initial perturbations. Accordingly, time average of the mode amplitude vanishes, as the initial amplitude approaches to zero. An exact solution is analytically given for a class of initial conditions. An excellent agreement is confirmed between the analytical solution and numerical results. The results obtained here provide a useful reference for basic benchmarking of theories and simulation of the ITG modes. (author)

British Library Electronic Table of Contents (United Kingdom)

An impingement jet system was used to study flow-assisted corrosion (FAC) of 3003 aluminum (Al) alloy in ethylene glycol-water solutions that simulates the automotive coolant by corrosion potential and electrochemical impedance spectroscopy (EIS) measurements as well as computational fluid dynamics (CFD) simulation. The effects of solution pH and fluid impact angle on Al FAC were determined. An increase of solution pH enhances the activity of Al due to dissolution of Al oxide film in alkaline environment. Moreover, Al activity decreases with the increasing fluid impact angle to the specimen. A CFD simulation shows that, with the increase of impact angle, the electrode area under high-velocity flow field decreases and that under low-velocity flow field increases. Consequently, the shear str...

Energy Technology Data Exchange (ETDEWEB)

The topic of supervised learning within the conceptual framework of artificial neural network (ANN) models is addressed. An ANN is a parallel distributed processing system that consists of many computationally simple processing elements interconnected through uni-directional weighted connections. Such networks, which are roughly patterned after biological nervous systems, have been proposed for use in areas in which the traditional von Neumann computer architecture has been relatively unsuccessful. Learning in these networks is accomplished through the use of algorithms that adjust the values of the connection weights. The work presented here addresses the issue of improving the rate at which ANNs can learn to achieve the mapping of an input pattern to a desired output pattern. The most successful learning algorithms for accomplishing this task are based on gradient descent error minimization techniques. However, the large amount of training ...

Science.gov (United States)

The Department of Defense (DoD) has long depended on military support functions enabled by space reconnaissance, surveillance, and target acquisition (RSTA) assets. Future generation satellite capabilities will further push technologies in space - if the right technologies are deployed in the right numbers and with the right payloads. Modeling and simulation play major parts in developing and deploying such assets: 1) system and operational requirements determination, and 2) assessment of military utility of such assets. Each area is critical in a system"s life cycle. Requirements determination cuts across the issues of doctrine, organizations, training, materiel, leader development, personnel, and facilities (DOTMLPF). Military utility assessments are necessary to explore and quantify the military worth/benefit of space RSTA assets to operational commanders. Each of these areas requires relevant ...

Science.gov (United States)

General balance laws and constitutive relations are developed for convective hydrothermal geothermal reservoirs. A fully interacting rock-fluid system is considered; typical rock-fluid interactions involve momentum and energy transfer, and the dependence ...

Energy Technology Data Exchange (ETDEWEB)

This guide describes the simulator`s governing equations, constitutive functions and numerical solution algorithms of the STOMP (Subsurface Transport Over Multiple Phases) simulator, a scientific tool for analyzing multiple phase subsurface flow and transport. The STOMP simulator`s fundamental purpose is to produce numerical predictions of thermal and hydrologic flow and transport phenomena in variably saturated subsurface environments, which are contaminated with volatile or nonvolatile organic compounds. Auxiliary applications include numerical predictions of solute transport processes including radioactive chain decay processes. In writing these guides for the STOMP simulator, the authors have assumed that the reader comprehends concepts and theories associated with multiple-phase hydrology, heat transfer, thermodynamics, radioactive chain decay, and nonhysteretic relative permeability, ...

Energy Technology Data Exchange (ETDEWEB)

There is a model on the Oak Ridge Reservation which provides requirements for determining capacities and capabilities related to low-level, hazardous, and mixed wastes. In FY 1987, the model will be sufficiently advanced to provide various waste management scenarios. These scenarios will be compared technically, operationally, and financially by use of waste characterization data and process simulators that are currently under development. The results of the process simulations will be used to help identify waste treatment, storage, and disposal technologies that need to be demonstrated prior to full-scale development for DOE use. The information derived from this effort will be made available to all DOE facilities.

International Nuclear Information System (INIS)

The effect of additives on the grafting of a monomer, butylmethacrylate (BA), into simul (a soft wood) has been studied using "6"0Co source at 3 Mrad. The enhancement of polymer loading (grafting) by the addition of minute amounts (1%) of oligomers and of polyfunctional monomers into simul + BA system has been further increased in the presence of acid and urea. The synergistic polymer loading yields by acid addition cause substantial decrease of tensile strength values of wood-plastic composite; but urea increases both polymer loading and tensile strength values synergistically in these systems. (author).

Energy Technology Data Exchange (ETDEWEB)

Previous models and evaluation techniques based on the Monte Carlo simulation for the reliability assessment of mixed hydrothermal generation systems are extended. Models for reservoirs on multiple rivers and pumped storage plants are developed. Operating and water management policies are extended to include the relative economical effects of operating alternative sources of generation. These effects and the benefits are described and discussed using an extended IEEE reliability test system. (Author).

Science.gov (United States)

This was written as the research final report of (sup D)evelopment of Auto- tuning System for the Process Optimal Control of Wolsung NPP(sup ()95ZS13). In this research, a new PID controller auto-tuning algorithm and Auto-tuning System which can simulate ...

Energy Technology Data Exchange (ETDEWEB)

A novel adaptive stabilizer, called an Adaptive Governor Power System Stabilizer (AGPSS), which operated on the governor turbine system, was described. There has been extensive research on adaptive excitation control of generators in power systems with the goal of achieving better dynamic performance. AGPSS tracks the frequency and damping of oscillations in a power system, and adjusts to ensure that there is always sufficient damping in the system. There is no interaction between stabilizers on different generating units, and each one acts independently, consuming oscillation energy locally. These stabilizers are easy to design and this facilitates their use in multimachine systems. Results obtained by nonlinear simulation of a single-machine and a three-machine power system were discussed, illustrating the ...

Energy Technology Data Exchange (ETDEWEB)

Orientational constraints obtained from solid state NMR experiments on anisotropic samples are used here in molecular dynamics (MD) simulations for determining the structure and dynamics of several different membrane-bound molecules. The new MD technique is based on the inclusion of orientation dependent pseudo-forces in the COSMOS-NMR force field. These forces drive molecular rotations and re-orientations in the simulation, such that the motional time-averages of the tensorial NMR properties approach the experimentally measured parameters. The orientational-constraint-driven MD simulations are universally applicable to all NMR interaction tensors, such as chemical shifts, dipolar couplings and quadrupolar interactions. The strategy does not depend on the initial choice of coordinates, and is in principle suitable for any flexible molecule. To test the method on three systems of increasing complexity, ...

Energy Technology Data Exchange (ETDEWEB)

A transient stability program was developed for the Taiwan Power Company, which has a high proportion of nuclear generation in its power system. This program offers a new territory to investigate nuclear plant effects on the power system transient stability. This program also provides a high speed tool for the Taipower system operational planning. A generalized procedure of synchronous machine modeling for a large-scale stability study is presented. The merits and weaknesses of machine modeling can be comprehended through each item of this procedure. Three types of nonlinear synchronous machine modeling implemented into this stability program are derived by following this procedure. A robust subroutine was derived to perform the fourth order Runge-Kutta integration method, making the software programming neat and systematical. For simulating the nuclear plant influence on the ...

Energy Technology Data Exchange (ETDEWEB)

Compares methods used at CEGB (UK), EdF (France), and ENEL (Italy) for generation planning studies with particular reference to those tools (or parts of them) that perform a yearly simulation of the generating system operation. Offers a short description of the composition of the 3 generating systems for a better understanding of the different philosophies employed. Comments on the frequency of utilization of the programs and on their main differences. Suggests that since the 3 systems show a tendency towards a more similar mix in the future (e.g. the percentage of hydro power plants will decrease both in the French and in the Italian system while the nuclear and coal base units will increase; all 3 systems will include an increasing share of pumped storage plants) the discussed planning problems will probably become common to the 3 systems. ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this project is to integrate a variety of geographic information systems capabilities and telecommunication technologies for potential use in geographic network and visualization applications. The specific technical goals of the project were to design, develop, and simulate the components of an audio/visual geographic communications system to aid future real-time monitoring, mapping and managing of transport vehicles. The system components of this feasibility study are collectively referred to as a Geographic Visualization and Communications System (GVCS). State-of-the-art techniques will be used and developed to allow both the vehicle operator and network manager to monitor the location and surrounding environment of a transport vehicle during shipment.

British Library Electronic Table of Contents (United Kingdom)

Concerning the requirements of future rocket technologies, providing a cost-efficient access to orbit as well as an increase in system reliability, a deeper insight into the unsteady phenomena during ascent of modern launchers is essential. Unsteady interactions and resonances of the turbulent separated launcher wake and the nozzle structure play an important role for the design of future main stage propulsion systems. The so-called buffeting coupling phenomenon is one of the main challenges during ascent. In the present study, a coupled simulation of the afterbody of the Ariane-5 launcher with a realistic structural and aerodynamic representation of different nozzle configurations is carried out. On the computational fluid dynamics side, unsteady detached eddy simulations are coupled with...

Energy Technology Data Exchange (ETDEWEB)

In this report is described the work effort performed to provide NETL with VE-Suite based Virtual Engineering software and enhanced equipment models to support NETL's Advanced Process Engineering Co-simulation (APECS) framework for advanced power generation systems. Enhancements to the software framework facilitated an important link between APECS and the virtual engineering capabilities provided by VE-Suite (e.g., equipment and process visualization, information assimilation). Model enhancements focused on improving predictions for the performance of entrained flow coal gasifiers and important auxiliary equipment (e.g., Air Separation Units) used in coal gasification systems. In addition, a Reduced Order Model generation tool and software to provide a coupling between APECS/AspenPlus and the GE GateCycle simulation system were developed. CAPE-Open model interfaces were ...

Energy Technology Data Exchange (ETDEWEB)

Chapter 2 describes the worldwide increase of primary energy consumption, which is expected in coming decades and results in possible solutions of a decentralised energy supply that is mainly based upon renewable energy carriers and the use of cogeneration systems. Chapter 3 shows the characteristics of decentralised system components that have been investigated in the frame of this research work as well as the resulting model library to depict the operational performance of the individual components and their mutual influence. A detailed dynamic simulation of a complete fuel cell system based on a steam reformer including the concept of local and superordinate control circuits is presented in chapter 4. Chapter 5 includes the integrated concepts for the intelligent and adaptable management of complex decentralised energy systems as well as a description of their implementation. ...

International Nuclear Information System (INIS)

The aim of this thesis is the design of a faults diagnosis-aiding system in a nuclear facility of the Cea. Actually the existing system allows the optimization of the production processes in regular operating conditions. Meanwhile during accidental events, the alarms, managed by threshold, are bringing no relevant information. To increase the reliability and the safety, the human operator needs a faults diagnosis-aiding system. The developed system, SECAPI, combines problem solving techniques and automatic learning techniques, that allow the diagnosis and the the simulation of various faults happening on nuclear facilities. Its reasoning principle uses case-based and rules-based techniques. SECAPI owns a learning module which reads out knowledge connected with faults. It can then simulate various faults, using the inductive logical computing. SECAPI has been ...

Energy Technology Data Exchange (ETDEWEB)

New measuring methods are developed and are tested with the small reactor simulator MIDAS (Mini Dodewaard ASsembly). The purpose of this work is to be able to measure accurately as many different properties of the flow as possible in the coming bigger simulator SIDAS (Simulated Dodewaard ASsembly). In SIDAS the flow around a fuel assembly of the Dutch Dodewaard reactor will be simulated. An extensive evaluation of the gamma detection system showed that the detection system could be simplified strongly. The simplified system is used to measure the radial and axial distribution of the void fraction in the core of MIDAS for three different operating conditions. Two new measuring methods have been developed and tested. A method to estimate the probability density of the void fraction in time. Due to the nonlinear relation between transmission ...

Energy Technology Data Exchange (ETDEWEB)

Installation of the major hardware subsystems for MFTF is nearing completion. These subsystems include the Fusion Chamber System, the eighty KV Neutral Beam System, the Superconducting Magnet System, and the Personnel Safety System. The Local Controls group has undertaken a uniform aproach to implementing the control systems for all of these hardware subsystems. This approach has two major aspects: (1) to provide a stand-alone computer control system with a remote, portable terminal so that computer control can be provided at the site of the hardware for initial testing, (2) to provide hardware simulators so that the complicated MFTF computer control system can be tested independent of the hardware. The software and hardware tools which were developed to carry out this plan will be described. Our experiences with ...

Energy Technology Data Exchange (ETDEWEB)

Molecular simulation aims at simulating particles in interaction, describing a physico-chemical system. When considering Markov Chain Monte Carlo sampling in this context, we often meet the same problem of statistical efficiency as with Molecular Dynamics for the simulation of complex molecules (polymers for example). The search for a correct sampling of the space of possible configurations with respect to the Boltzmann-Gibbs distribution is directly related to the statistical efficiency of such algorithms (i.e. the ability of rapidly providing uncorrelated states covering all the configuration space). We investigated how to improve this efficiency with the help of Artificial Evolution (AE). AE algorithms form a class of stochastic optimization algorithms inspired by Darwinian evolution. Efficiency measures that can be turned into efficiency criteria have been first searched before identifying ...

Energy Technology Data Exchange (ETDEWEB)

The operation of equipment in a mine produces a complex system which requires monitoring, simulation, analysis and reconciliation to ensure optimum production. The work described in the paper represents the initial steps in an overall program to enable optimization of production and equipment usage. Two areas of investigation are covered in some detail. The first concerns large haul trucks which accomplish much of the movement of minerals and wastes in many open pit mining operations. The monitoring of trucks in normal operation is described along with some of the results of such work. The second concerns draglines which are similarly important in moving overburden in many coal mines. A program of computer simulation of draglines is described. This shows the benefits of a simulation model which can be used to determine the effects of productivity of small changes in stripping procedure or dragline ...

Energy Technology Data Exchange (ETDEWEB)

The application of HVDC system to the trunk power supply system requires the transmission of DC power as much as possible to improve the stability of the whole AC/DC system. To meet this requirement, continued pulse system, which keeps sending a DC current even when an AC voltage lowers remarkably, has been used. The stability is much more improved by adding damping control which modulates converter active and/or reactive power. In order to make full use of such control effects, it is important that the HVDC system maintains stable operation during faults and reclosing of the AC system. In particular, it is necessary to prevent a repetitive commutation failure following the unbalanced AC transmission line faults. In this paper, the cause of the repetitive commutation failure is discussed by using the AC-DC power system ...

International Nuclear Information System (INIS)

Different types of radioactive liquid waste are being generated at Advanced Fuel Fabrication Facility (AFFF), Tarapur during the quality control analysis of the mixed oxide (MOX) fuel pellets. A laboratory scale study was performed for treatment of such waste. Some of the waste streams originating from U and Pu analysis contain components like sulphate and phosphate which interfere during chemical precipitation of alpha activity from the waste. Various chemical co-precipitation experiments were conducted based on alkaline precipitation. Reductive precipitation using sodium sulphite and Fe(II) was found to be promising and the same was suggested for plant scale treatment. (author)

International Nuclear Information System (INIS)

Simple hydroxamic acids are shown to be useful reagents for the separation of Np and Pu from U within simplified, single cycle Purex flowsheets. They are compatible with the use of centrifugal contactors and laboratory scale flowsheet trials with aceto-hydroxamic acid have demonstrated high actinide recoveries and decontamination factors on products for active feeds of up to 40 wt.% Pu. They therefore show many ideal characteristics for Pu and Np recovery within flowsheet options for actinide recovery in advanced fuel cycles. Furthermore, in order to optimise the routing of Np with the Pu product in advanced flowsheets, additional studies of Np extraction in the primary co-decontamination contactor, prior to U/Pu partition, have been undertaken, combining experiment, modelling and flowsheet tests. (author)

Energy Technology Data Exchange (ETDEWEB)

This paper reported on a study in which rapeseeds were separated into high quality seed for food oil and low quality seed for biofuels. A laboratory-scale oilseed screw press was then used to examine the effects of choke opening and seed preheating on the rapeseed pressing performance and the quality of food oil and biofuels oil. Oil recovery and chlorophyll content was found to increase as maximum pressure increased. In terms of pressing performance, the rapeseed heated by microwaves yielded more oil and chlorophyll than without heating. The NEB ratio of microwave heating press with an 8.0 mm choke opening was advantageous. Rapeseed oil extracted from low quality seeds was found to have a high acid value. The quality of oil extracted by oilseed screw press was found to be good and met the requirements of the Codex Alimentarius for edible oils.

Energy Technology Data Exchange (ETDEWEB)

This final report for the Swiss Federal Office of Energy (SFOE) reports on work done in the area of gasification of biomass. The use of dung, manure and sewage sludge as sources of energy is described and discussed. Hydrothermal gasification is proposed as an alternative to conventional gas-phase processes. The aim of the project in this respect is discussed. Here, a catalytic process that demonstrates the gasification of wet biomass to synthetic natural gas (SNG) in a continuously operating plant on a laboratory scale is being looked at. Difficulties encountered in preliminary tests are discussed. Long-term catalyst stability and the installations for the demonstration of the process are discussed, and gasification tests with ethanol are commented on.

British Library Electronic Table of Contents (United Kingdom)

The Monte Carlo ray-tracing method is applied and coupled with optical properties to predict the radiation performance of solar concentrator/cavity receiver systems. Several different cavity geometries are compared on the radiation performance. A flux density distribution measurement system for dish parabolic concentrators is developed. The contours of the flux distribution for target placements at different distances from the dish vertex of a solar concentrator are taken by using an indirect method with a Lambert and a charge coupled device (CCD) camera. Further, the measured flux distributions are compared with a Monte Carlo-predicted distribution. The results can be a valuable reference for the design and assemblage of the solar collector system.

Energy Technology Data Exchange (ETDEWEB)

There is very little quantitative documentation of actual improvements resulting from the installation of new general ventilation systems in industrial settings. Therefore the performance of the common mixing design principle was compared to the displacement design principle by means of an intervention study in a workshop (V = 12,000 m[sup 3]), where thermoplastics were moulded. An experimental signal-response tracer gas technique was used. In terms of supplying fresh air to the zone of occupancy the displacement system was better than the mixing system by a factor of 2. In terms of the exposure level to a simulated contaminant (tracer gas) the displacement system was better by a factor 1.5-18. (author)

Science.gov (United States)

We develop a 3-D model to simulate the synthetic aperture radar (SAR) image formation process of an undulated vegetation canopy such as corn grown in fields with large periodic drainage reliefs. We explain how the simulated SAR image of undulated vegetation medium is obtained by the convolution of a 2-D slice of the 3-D simulated SAR system point spread function [(PSF), emulating the SAR beam modeled by a cosine modulated Gaussian], with the 2-D projection of the observed undulated vegetation canopy (modeled with scatterers randomly distributed in 3-D undulated space) followed by the extraction of each look envelope, the summation of looks, and sampling in azimuthal and range directions. Our model is useful to study the parameters involved in the formation and the analysis of SAR images of undulated vegetation medium. Validation of simulations made with actual SAR images shows that ...

Energy Technology Data Exchange (ETDEWEB)

A pipeless batch plant is a batch processing production system using mobile vessels. The plant performances depend on both hardware of equipment and software of operation. So the plant includes many design factors such as number of vessels, stations and AGVS, layout of stations, vessel moving rules, job scheduling and so on. In this paper, the characteristics of pipeless batch plant design are considered to handle the problem by the systems engineering approach. Then, a practical design method known as design-by-analysis is applied to solve such a complex design problem. Based on this concept, a design support system composed of modeling, simulation and evaluation subsystems is developed. This system enables rational decision making through performance evaluation for proposed design of a pipeless batch plant. The usefulness of the system is illustrated by ...

Energy Technology Data Exchange (ETDEWEB)

In the frame of the comprehensive assessment of Swiss energy systems, air quality simulations were performed by using a 3-dimensional photo-chemical dispersion model. The objective is to investigate the impacts of pollutants in Switzerland for future options of Swiss energy systems. Four scenarios were investigated: Base Case: simulations with the projected emissions for the year 2030, Scenario 1) all nuclear power plants were replaced by oil-driven combined cycle plants (CCP), Scenarios 2 to 4) traffic emissions were reduced in whole Switzerland as well as in the cities and on the highways separately. Changes in the pollutant concentrations and depositions, and the possible short-term impacts are discussed on the basis of exceedences of critical levels for plants and limits given to protect the public health. (author) 2 figs., 7 refs.

International Nuclear Information System (INIS)

Data from Monte Carlo transport codes are used to model radiobiological effects. We previously reported the Fourier analysis of ionization data generated by simulating a 500-keV proton traversing water. Here, we extend Fourier analysis to energy transfer data of another radiation type, a 14-MeV #alpha#-particle. A radiobiological model based on this frequency-domain analysis views cell as an information processing system . It lends itself naturally to traditional engineering analyses. One engineering principle-the output response of a linear system to random signal-is applied here to explain the fact that there is measurable difference in the magnitude of the biological effectiveness when a given biological system is irradiated with two different radiation types of the same Linear Energy Transfer (LET).

CERN Document Server

One of the major challenges facing the proposed high-energy linear e^+e^ colliders is the preservation of the extremely small vertical emittance from the damping rings to the interaction point (IP). This emittance must be transported through bunch compression sections, the main linac and finally through the beam delivery system to the IP. Historically, the beam dynamics issues of each subsystem have been studied quasi-independently, with the beam conditions and tolerances being specified at the boundaries. As part of the recent International Linear Collider Technical Review Committee, new simulation tools have been developed to simulate the beam transport through the integrated system, including static and dynamic errors, stabilization systems, and tuning algorithms.

Energy Technology Data Exchange (ETDEWEB)

The results presented here demonstrate that the Paul Trap Simulator Experiment (PTSX) simulates the propagation of intense charged particle beams over distances of many kilometers through magnetic alternating-gradient (AG) transport systems by making use of the similarity between the transverse dynamics of particles in the two systems. Plasmas have been trapped that correspond to normalized intensity parameters s = wp2 (0)/2wq2 * 0.8, where wp(r) is the plasmas frequency and wq is the average transverse focusing frequency in the smooth-focusing approximation. The measured root-mean-squared (RMS) radius of the beam is consistent with a model, equally applicable to both PTSX and AG systems that balances the average inward confining force against the outward pressure-gradient and space-charge forces. The PTSX device confines one-component cesium ion plasmas for hundreds of ...

Energy Technology Data Exchange (ETDEWEB)

Design considerations of a combined photovoltaic-thermal (PV-T) system for a particular site and application must include thermal and electrical tradeoffs. A simplified technique for determining preliminary design and economic analyses would minimize costly computer simulation and indicate feasibility. To that end, nomographs that size an array to meet a specific annual load and determine the subsequent cost savings have been developed, and are presented in this paper.

British Library Electronic Table of Contents (United Kingdom)

A method for transforming the Euler and Navier-Stokes equations and a complete system of fluid dynamics equations in three dimensions to a closed system on any moving surface is proposed. As a result, for an arbitrary geometric configuration, the dimension of the equations is reduced by one, which makes them convenient for numerical simulation. The general principles of the method are described, and verifying examples are presented.

International Nuclear Information System (INIS)

In this paper, we propose a simple method for controlling an electromagnetic levitation (Mag lev) system. The model of the Mag lev system under consideration in this paper is third order, inherently nonlinear and unstable. For designing a controller to obtain a good disturbance rejection and being insensitive to parameter variations, we use an inner-loop and an outer-loop configuration. The configuration is the key to solve this problem. By using a nonlinear state transformation in the feedback path, a cascaded PI controller and a redefined input in the inner loop, we obtain a linear second order system. Furthermore, to achieve a stable system with a good disturbance rejection, we design a Pid controller cascaded with the inner loop system in the negative unity feedback configuration in the outer loop. We show that the closed-loop system is robustly stabilized ...

International Nuclear Information System (INIS)

A model for the simulation of the time dependent behavior and the analysis of the equilibrium of the coupled system of storage ring and Free Electron Laser (FEL) is presented. The analysis comprises both amplifier and oscillator FEL. Bunch lengthening and energy widening due to wake forces are taken into account in a self-consistent way. The method is based on a mapping algorithm for means and correlations of the electron distribution function, pioneered by K. Hirata. The evolution of the laser field in the oscillator FEL is described by K. Hirata. The evolution of the laser field in the oscillator FEL is described by supermodes. The model is used to simulate an FEL in a small 500 MeV storage ring with 100 m circumference. Typical values for the output power, spatial, and spectral characteristics of the emitted radiation are presented.

International Nuclear Information System (INIS)

Energy savings from the use of daylighting in commercial buildings are realized through implementation of photoelectric lighting controls that dim electric lights when sufficient daylight is available to provide adequate workplane illumination. The dimming level of electric lighting is based on the signal of a photosensor. Current simulation approaches for such systems are based on the questionable assumption that the signal of the photosensor is proportional to the task illuminance. This paper presents a method that simulates the performance of photosensor controls considering the acceptance angle, angular sensitivity, placement of the photosensor within a space, and color correction filter. The method is based on the multiplication of two fisheye images: one generated from the angular sensitivity of the photosensor and the other from a 180- or 360-degree fisheye image of the space as ''seen'' by the photosensor. The paper ...

Environmental Research Database

Objectives(i) Investigate the correlation between Antarctic sea-ice and equatorial sea-surface temperature anomalies in a realistically forced ocean model simulation of the last 50 years. (ii) Determine whether and how the enormous seasonal change in distribution of sea-ice modifies the seasonal cycle at the Equator. (iii) Determine the detailed pathways of wave propagation both in a historically-forced simulation and in response to realistic perturbations. (iv) Quantify the amplitude of the response i [continued...]DescriptionIt is well known that the equatorial ocean-atmosphere system plays a key role in global climate events such as the El Nino-Southern Oscillation (ENSO) phenomenon. There is now compelling evidence that changes in the Antarctic can strongly and quickly affect the equatorial ocean and the ENSO cycle. Observations demonstrate statistically significant correlations (teleconnections) between the Antarctic ...

International Nuclear Information System (INIS)

The present work summarizes efforts on the simulation of natural convection cooling within the IFMIF target and test cell. The simulations have been performed with the STAR-CD code using the k-#omega# high-Reynolds number turbulence model. A dedicated thermohydraulic model has been devised including Lithium loop components. Nuclear heat production has been calculated by the Monte-Carlo code McDeLicious for different parts of the target and test cell walls and was used as input for the STAR-CD simulations. Helium atmospheres at several pressures from 0.1 to 10"-"5 MPa have been investigated. In order to limit the maximum temperature of the concrete walls to 80 deg. C it was necessary to add thermal insulation layers to the hot Lithium loop surfaces and a conceptual system of two cooling layers in different depths of the concrete walls.

Energy Technology Data Exchange (ETDEWEB)

This report summarizes some experiences gathered when using the semi-empirical temperature model that forms the heart of the steel casting advisory system `TUNDTEMP` in simulating the casting process. The model estimates the evolution of the liquid steel temperature in a tundish of a continuous casting machine through a temperature prediction at a couple of central time instants during the casting process. The results are compared with corresponding actual observations during the castings - measured steel temperatures and recorded casting difficulties and interruptions. Explanations for the possible discrepancies are suggested. Starting from a heuristically chosen set of model parameter values, some developing steps have been tested to reduce the simulation errors. The study concentrates mainly on temperature predictions for single heat castings. At the end of the report, some simulations of sequence ...

CERN Document Server

Brachytherapy is a radiotherapeutic modality that makes use of radionuclides to deliver a high radiation dose to a well-defined volume while sparing surrounding healthy structures. At the National Institute for Cancer Research of Genova a High Dose Rate remote afterloading system provides Ir(192) endocavitary brachytherapy treatments. We studied the possibility to use the Geant4 Monte Carlo simulation toolkit in brachytherapy for calculation of complex physical parameters, not directly available by experiment al measurements, used in treatment planning dose deposition models.

Energy Technology Data Exchange (ETDEWEB)

A method, which estimates the lightning performance of high voltage transmission lines based on the Monte-Carlo simulation technique, is described in this paper. The average number of faults which occur in a transmission line, dividing them in single-phase and three-phase faults, as well as the average grounding resistances of the transmission lines are calculated. The method is applied, on several operating Greek transmission lines, showing good correlation between predicted and field observation results. The proposed method can be used as a useful tool in the design of electric power systems, aiding in the right insulation dimensioning of a transmission line.(author)

International Nuclear Information System (INIS)

Development progress of the full-flow engine fluidic control system is reported. The fluidic temperature control subsystem was transferred from IR and D status to the SNP-1 program contract 1 December 1969. Several new fluidic control concepts were explored either experimentally or analytically. Basic component and subsystem design data at simulated engine state-point conditions were secured. Component design effort during the next six months will include fabrication and simulated tests of selected ''breadboard'' configurations. (auth).

Energy Technology Data Exchange (ETDEWEB)

The underlying theory and model of capacitive voltage substations and its associated problems are described. This system is intended to supply electricity to rural communities directly from high-voltage transmission lines. This technique leads to important cost reductions when compared with conventional alternatives. However, in several transient cases, some problems such as ferroresonance and overvoltages could occur in these substations. Using a developed capacitive substation model these transient cases are simulated. A suitable filter is designed to damp overvoltages clue to ferroresonance. Analytical aspects of filter design are presented and some computer simulation tests are provided to highlight the usefulness of the proposed filter. (author)

Energy Technology Data Exchange (ETDEWEB)

The formation of a quasiequilibrium beam distribution matched to an alternating-gradient quadrupole focusing lattice by means of the adiabatic turn-on of the oscillating focusing field is studied numerically using particle-in-cell simulations. Quiescent beam propagation over several hundred lattice periods is demonstrated for a broad range of beam intensities and vacuum phase advances describing the strength of the oscillating focusing field. Properties of the matched-beam distribution are investigated. In particular, self-similar evolution of the beam density profile is observed over a wide range of system parameters. The numerical simulations are performed using the WARP particle-in-cell code.

International Nuclear Information System (INIS)

A Siemens Mevatron KV2 accelerator installed at the Royal Adelaide Hospital employs cylindrical solid-walled electron cones for some electron collimation. The cones being used at present result in treatment fields that do not always conform with the International Electrotechnical Commission (IEC) Standards (particularly at high energies). The aim of this project was to simulate the existing cones using Monte Carlo methods in order to evaluate potential cone modifications required to overcome the field irregularities. Simulations were performed using the EGS4 (Electron Gamma Shower version 4, distribution II) Monte Carlo code installed on a DEC Alpha workstation at the University of South Australia. To rigorously simulate the existing electron cones it was necessary to also simulate various components within the treatment head of the linear accelerator. Results of simulations for ...

Energy Technology Data Exchange (ETDEWEB)

This paper is devoted to the coordination of secondary voltage control and adaptive parameters resetting of the power system stabilizer, in order to increase stability, margins in real time operation. Secondary voltage control and the power system stabilizer are two control loops, which affect the same system parameter on different bases - that parameter is the voltage set-point of the automatic voltage regulator. It was found that their effects were complementary. In that way, through the proper coordination of actions of these two control loops open up a wide range of possibilities for ensuring the stability of bulk power systems in real time. For the establishment of this coordination, an on-line sequential algorithm is proposed which is based on adaptive resetting of the voltage set-point of the automatic voltage regulator and the PSS parameters. The efficiency of the proposed algorithm is confined ...

Science.gov (United States)

In order to increase the speed of photoelectric conversion, a linear CCD is applied as the photoelectric converter instead of the traditional photodiode. A white LED is used as the light source of the system. The color information of the urine test strip is transferred into the CCD through a reflecting optical system. It is then converted to digital signals by an A/D converter. The test results of urine analysis are obtained by a data processing system. An ARM microprocessor is selected as the CPU of the system and a CPLD is employed to provide a driving timing for the CCD drive and the A/D converter. Active HDL7.2 and Verilog HDL are used to simulate the driving timing of the CPLD. Experimental results show that the correctness rate of the test results is better than 90%. The system satisfies the requirements of the color information collection of urine ...

International Nuclear Information System (INIS)

The RELAP5 code has been developed for best-estimate transient simulation of light water reactor coolant systems during postulated accidents. The code models the coupled behavior of the reactor coolant system and the core for loss-of-coolant accidents and operational transients such as anticipated transient without scram, loss of offsite power, loss of feedwater, and loss of flow. A generic modeling approach is used that permits simulating a variety of thermal hydraulic systems. Control system and secondary system components are included to permit modeling of plant controls, turbines, condensers, and secondary feedwater systems. RELAP5/MOD3 code documentation is divided into seven volumes: Volume I presents modeling theory and associated numerical schemes; Volume II details instructions for code application and input ...

International Nuclear Information System (INIS)

The Four years of the IMPACT, 'Integrated Modular Plant Analysis and Computing Technology', project Phase 1 have been completed. The verification study of Severe Accident Analysis Code SAMPSON prototype developed in Phase 1 was conducted in two steps. First, each analysis module was run independently and analysis results were compared and verified against separate-effect test data with good results. Second, with the Simulation Supervisory System, up to 11 analysis modules were executed concurrently in the parallel environment (currently, NUPEC uses IBM-SP2 with 72 process elements), to demonstrate the code capability and integrity. The target plant was Surry as a typical PWR and the initiation events were a 10-inch cold leg failure. The analysis is divided to two cases; one is in-vessel retention analysis when the gap cooling is effective (In-vessel scenario test), the other is analysis of phenomena event is extended to ex-vessel due to the ...

Energy Technology Data Exchange (ETDEWEB)

This dissertation deals with the control of active power flow, or load flow in electric power systems. During the last few years, interest in the possibilities to control the active power flows in transmission systems has increased significantly. There is a number of reasons for this, coming both from the application side - that is, from power system operations - and from the technological side. where advances in power electronics and related technologies have made new system components available. Load flow control is by nature a multi-input multi-output problem, since any change of load flow in one line will be complemented by changes in other lines. Strong cross-coupling between controllable components is to be expected, and the possibility of adverse interactions between these components cannot be rejected straightaway. Interactions with dynamic phenomena in the power system are ...

Energy Technology Data Exchange (ETDEWEB)

A new approach for the selection of best PSS locations in multimachine power systems is proposed in this paper. Study shows that the right-eigenvector measures the activity of state variables and the left-eigenvector measures the control effect of control signals. Based on the right and left eigenvector the concept of sensitivity of PSS effect (SPE) is presented and used to identify the best PSS locations. The proposed method is used to identify the best PSS location in a 13-machine system to increase the damping of an interarea mode. The time-domain simulation results confirm that the prediction of best PSS location by SPE method is correct and accurate.

Energy Technology Data Exchange (ETDEWEB)

This paper describes the main aspects and results of the planning studies undertaken to evaluate the technical benefits of using Thyristor Controlled Series Compensation (TCSC), in a large 500 kV transmission system (Brazilian North-Northeast system). TCSC controllers design and simplified models for digital non-linear time domain simulations are discussed. The proposed controllers are tuned and used to support the comparative analysis between controlled and fixed series compensation. The relevant conclusions concerning this comparison are highlighted. (author) 2 refs., 14 figs., 3 tabs.

CERN Document Server

We consider the adiabatic demagnetization in the rotating reference frame (ADRF) of a system of dipolar coupled nuclear spins $s=1/2$ in the external magnetic field. The demagnetization starts with the offset of the external magnetic field (in frequency units) from the Larmor frequency being several times greater than the local dipolar field. For different subsystem sizes, we have found from numerical simulations the temperatures at which subsystems of a one-dimensional nine-spin chain and a plane nine-spin cluster become entangled. These temperatures are of the order of microkelvins and are almost independent of the subsystem size. There is a weak dependence of the temperature on the space dimension of the system.

International Nuclear Information System (INIS)

CIRNAT, a one-dimensional code for natural circulation analysis, was described. The homogeneous approach was adopted for the two-phase flow regime and different heat transfer regimes were considered. The code was exhaustively tested for one-phase flow systems. For two phase flows a boiling/condensing system was simulated. The results are qualitatively correct but the oscillations observed at the system were not captured by the model. Other two-phase flow tests must be done to show the limits of the homogeneous approach before the introduction of a more complex model. (author)

Energy Technology Data Exchange (ETDEWEB)

A probabilistic method for assessing the profitability of reactive power compensation devices such as capacitors, static VAR compensators and generators, which improve network security, was described. Since network development is limited by environmental constraints, power networks are operated close to their limits. Because of this fact transmission network planning increasingly relies on techno-economic models to improve network security and profitability. The proposed method consists of analyzing large numbers of constrained power system states, extracted from power system simulation exercises. The paper describes details of the method and provides an example of a numerical application on a part of the French power transmission system. 10 refs., 8 figs.

DEFF Research Database (Denmark)

This thesis - Resource Management in Broadband Communication Networks - deals with different ways of optimizing the available resources of data- or telecommunication networks. Especially topics like optimal routing, load balancing and fast recovery of routes in case of link failures are covered. The first part gives a brief description of some of the existing protocols for routing and controlling resources, such as RSVP, OSPF, BGP, PNNI, etc. The remaining part concerns the following two fundamentally different approaches to resource management etc.: - Software agents - Simulated ants In the beginning of the part concerning software agents a description of what exactly constitutes software agents, according to the scientists and according to the organization, FIPA is given. After this, the main results from the IMPACT project are presented. The IMPACT project is an EU-project that aimed at developing a demonstration platform, where software agents handled virtually ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents a mathematical model for simultaneous heat and moisture transfer under freezing-thawing in porous hygroscopic material. Even below O{sup o}C, unfrozen liquid water exists in the material which plays an important role in the processes. The model takes into account the existence of unfrozen liquid water. The system is treated as a three-(gas, liquid and solid) phase system of water. Moisture chemical potential is used as a moisture potential. Under freezing, moisture chemical potential is a unique function of local temperature. So, during freezing, two unknown variables to be solved are solid water content and moisture potential or temperature. A simple example of simulation for freezing processes is shown. (author)

Energy Technology Data Exchange (ETDEWEB)

Since actinide mononitride has several superior thermal and neutronic properties, nitride fuel is considered as a candidate for future nuclear systems, such as advanced fast reactors and accelerator-driven system. Establishing reprocessing technology is one of key technologies for the development of nitride fuel cycle. In addition to general advantages of pyrochemical process, such as the potential for economy, radiation and proliferation resistance, recycling of N-15 in nitride fuel seems to be practical in comparison with conventional hydro-process. Following the electrochemical measurements of nitride fuel in LiCl-KCl molten salt, the experimental study on closing nitride fuel cycle has been carried out in JAEA by used of TRU nitride and burnup simulated nitride samples. Recent progress of the study is summarized in this paper.

British Library Electronic Table of Contents (United Kingdom)

A study of the ordinary mild steel/cooling water interface, with and without inhibitor, was carried out using electrochemical impedance spectroscopy (EIS). EIS spectra in uninhibited medium reveal that a layer of corrosion and scale products is formed naturally and evolves with the immersion time. Monosaccharides derivatives were used as corrosion inhibitors. Most of them exhibit good behaviour against corrosion of ordinary steel in simulated water systems. Their inhibiting efficiency increases with concentration rise and depends on molecular structure especially -OH groups' position on two adjacent carbons and their number. In addition, the effect of MoO4^2^- on the corrosion inhibition in the presence of the best inhibitor was also studied by EIS. The addition of MoO4^2^- enhanced the in...

Energy Technology Data Exchange (ETDEWEB)

Gamma scanning measurements are used to determine the radioactive nuclides from an irradiated fuel rod in a hot cell which is a routine task in the Irradiated Materials Examination Facility (IMEF) of the Korea Atomic Energy Research Institute (KAERI), Total gamma spectra of radioactive nuclides and the atomic ratio of {sup 134}Cs to {sup 137}Cs in a few segments of a single fuel rod are measured by the present gamma scanning system. For the purpose of determining the radioactive nuclide's distribution in detail within a fuel rod quantitatively, we attempt to upgrade the present gamma scanning system in this paper, therefore, an investigation of the feasibility of the tomographic gamma scanning (TGS) technique, which is one of the promising nondestructive assay (NDA) methods is proposed. The TGS technique is an efficient method and it has an accurate precision for the characterization of several fuel parameters. In this paper, a ...

International Nuclear Information System (INIS)

The Accelerator Transmutation Waste System is under development at the Los Alamos National Laboratory. The goal is to perform an independent verification of the feasibility of actinide and long-lived fission product burning in this system. The authors' work is divided into five tasks: (a) production of an actinide and long-lived fission product cross section library from JEF 2.2; (b) simulation using MCNP and KENO IV Monte Carlo codes, of the Accelerator Transmutation Waste System configurations existing in literature; (c) validation of HETC Monte Carlo code (production of spallation source); (d) validation of the cross sections by comparison of Keff and reaction rate results, calculated with MNCP and KENO IV, with experimental benchmarks and intercomparison between the authors' calculations of a PWR unit cell and the computations carried out with various codes and cross section libraries (NEACRP ...

Energy Technology Data Exchange (ETDEWEB)

This paper reports the study results on the standard weather data necessary for simulation of PV power generation systems in fiscal 1994. In the study on the selection criterion of the standard weather data from the viewpoint of PV power generation systems, three typical years are used; a year with average solar radiation, and two years with extremely less and more solar radiation for safe simulation. The standard weather data are arranged for output calculation of PV power generation systems by selecting the most typical year based on long-term observation data. The data to be arranged are as follows; total, direct and scattered solar radiations incident upon a horizontal surface, solar radiation upon a slope surface, sunshine duration, air temperature, wind direction, wind velocity, amount of precipitation, and snow depth. For arrangement of the nationwide standard weather data, ...

Energy Technology Data Exchange (ETDEWEB)

In this paper the newly developed discrete-time adaptive sliding mode control method is proposed and applied to the power system stabilization problem. In contrast to the conventional continuous-time sliding mode controller, the proposed method is developed in the discrete-time domain and based on the input/output measurements instead of the continuous-time and the full-states feedback, respectively. Because the proposed control method has the adaptivity property in addition to the natural robustness property of the sliding mode control, it is possible to design the power system stabilizer which can overcome both the minor variations of the parameters of the power system and the diverse operating conditions and faults of the power system. Mathematical proof and the various computer simulations are done to verify the performance and stability of the proposed method. (author). 14 ...

Energy Technology Data Exchange (ETDEWEB)

The aim of this work is the evaluation of the quality of a chemistry-transport model, not by a classical comparison with observations, but by the estimation of its uncertainties due to the input data, to the model formulation and to the numerical approximations. The study of these 3 sources of uncertainty is carried out with Monte Carlo simulations, with multi-model simulations and with comparisons between numerical schemes, respectively. A high uncertainty is shown for ozone concentrations. To overcome the uncertainty-related limitations, a strategy consists in using the overall forecasting. By combining several models (up to 48) on the basis of past observations, forecasts can be significantly improved. This work has been also the occasion of developing an innovative modeling system, named Polyphemus. (J.S.)

Energy Technology Data Exchange (ETDEWEB)

The technology for performance testing and improvement of materials which are durable at space environment is a military related technology and veiled and securely regulated in advanced countries such as US and Russia. This core technology cannot be easily transferred to other country too. Therefore, this technology is the most fundamental and necessary research area for the successful establishment of space environment system. Since the task for evaluating the effects of space materials and components by space radiation plays important role in satellite lifetime extension and running failure percentage decrease, it is necessary to establish simulated space radiation facility and systematic testing procedure. This report has dealt with the status of the technology to enable the simulation of space environment effects, including the effect of space radiation on space materials. This information such as the fundamental ...

International Nuclear Information System (INIS)

Monte-Carlo simulations of 2-MeV #alpha#-particle channeling in Si_1_-_xSn_x alloys with 0#<=#x#<=#1 have been performed. The simulations are compared with measured channeling-angular scans for strained Si_0_._9_5Sn_0_._0_5 layers grown by molecular beam epitaxy (MBE). Agreement between simulated and measured angular scans can only be achieved if we assume a deviation of the crystal structure from the ideal one. This deviation can be attributed to a mosaic structure in the films and to an atomic-scale distortion of the crystal lattice due to an expected difference in the bond lengths between the Si-Si, Si-Sn and Sn-Sn atoms (such a difference in bond lengths has been observed in the epitaxial Si_1_-_xGe_x system). The contributions from both of these imperfections are estimated and discussed.

Energy Technology Data Exchange (ETDEWEB)

The uptake of sup(99m)Tc-methylenediphosphonate (MDP) in different parts of rat femur was simulated using a local three-space model for tracer transfer. The model consisted of bone blood, bone ECF-space and space for tracer deposition. The measured sup(99m)Tc-MDP concentration in the systemic blood and the local bone blood flow measured by /sup 131/I-macroaggregated albumin microspheres were used as input parameters. The measured blood flow values were 6.3, 3.1 and 15.3 ml/100 g/min for proximal, middle and distal femur, respectively. the model parameters that gave the best fit to measured sup(99m)Tc-MDP uptake curves in computer simulation showed that bone blood flow, volume of ECF-space, permeability surface area product and accretion constant from ECF-space to space for tracer deposition were highest in distal and lowest in middle femur. The values corresponded to peak extraction fractions of 0.38, 0.62, and 0.31 for ...

Energy Technology Data Exchange (ETDEWEB)

The fuel composition heterogeneity effect on reactor performance parameters was assessed by refueling simulations for three DUPIC fuel options of fuel composition heterogeneity control: the fissile content adjustment, the reactivity control by slightly enriched and depleted uranium, and the reactivity control by natural uranium. For each DUPIC fuel option, the simulations were performed using 30 heterogeneous fuel types which were determined by the agglomerative hierarchical clustering method. The heterogeneity effect was considered during the refueling simulation by randomly selecting fuel types for the refueling operation. The refueling simulations of the heterogeneous core have shown that the key performance parameters such as the maximum channel power (MCP), maximum bundle power (MBP), and channel power peaking factor (CPPF) are close to those of the core that has single fuel type. For the three ...

Energy Technology Data Exchange (ETDEWEB)

In order to study the two-phase natural circulation and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed using two different thermal-hydraulic loops. The main focus of the experiment was the two-phase flow behavior in the hot-leg U-bend typical of BandW LWR systems. The first group of experiments was carried out in the nitrogen gas-water adiabatic simulation loop and the second in the Freon 113 boiling and condensation loop. Both of the loops have been designed as a flow visualization facility and built according to the two-phase flow scaling criteria developed under this program. The nitrogen gas-water system has been used to isolate key hydrodynamic phenomena such as the phase distribution, relative velocity between phases, two-phase flow regimes and flow termination mechanisms, whereas the Freon loop has been used to study the effect of ...

Energy Technology Data Exchange (ETDEWEB)

Glass produced during the Purex 4 campaigns of the Integrated DWPF Melter System (IDMS) and the 774 Research Melter contained a lower fraction of sludge components than targeted by the Product Composition Control System (PCCS). Purex 4 glass was more durable than the benchmark (EA) glass, but was less durable than most other simulated SRS high-level waste glasses. Further, the measured durability of Purex 4 glass was not as well correlated with the durability predicted from the DWPF process control algorithm, probably because the algorithm was developed to predict the durability of SRS high-level waste glasses with higher sludge content than Purex 4. A melter run, designated Purex 4 Remediation, was performed using the 774 Research Melter to determine if the initial PCCS target composition determined for Purex 4 would produce acceptable glass whose durability could be accurately modeled by the DWPF glass durability ...

International Nuclear Information System (INIS)

A push for electric vehicles has occurred in the past several decades due to various concerns about air pollution and the contribution of emissions to global climate change. Although electric cars and buses have been the focus of much of electric vehicle development, smaller vehicles are used extensively for transportation and utility purposes in many countries. In order to explore the viability of fuel cell - battery hybrid electric vehicles, empirical fuel cell system data has been incorporated into the NREL's vehicle design and simulation tool, ADVISOR (ADvanced Vehicle SimulatOR), to predict the performance of a low-speed, fuel cell - battery electric vehicle through MATLAB Simulink. The modelling and simulation provide valuable feedback to the design optimization of the fuel cell power system. A sampling based optimization algorithm was used to explore the viability and options ...

International Nuclear Information System (INIS)

In a positive polarity induction adder each of the induction cavities is a cathode, which emits electrons at a unique potential. These broad spectrum electrons strongly affect Magnetically Insulated Transmission Line (MITL) behavior. Electron flow decreases the cavity-to-MITL coupling efficiency, and reduces the power transport efficiency along the system. Also, the operating impedance of the MITL is lowered, reducing the diode impedance required for good coupling and good total system power efficiency. It is therefore imperative to understand the details of MITL electron flow. In previous work, measurement of MITL electron flow for a twenty-stage linear induction adder (Hermes III), operated in positive polarity, was compared with simulations. There was qualitative agreement, but some differences were noted. For example, measured electron flow in the first cavities was greater than in the simulations. ...

International Nuclear Information System (INIS)

Accurate dose calculation in radiation treatment planning is most important for successful treatment. Since human body is composed of various materials and not an ideal shape, it is not easy to calculate the accurate effective dose in the patients. Many methods have been proposed to solve inhomogeneity and surface contour problems. Monte Carlo simulations are regarded as the most accurate method, but it is not appropriate for routine planning because it takes so much time. Pencil beam kernel based convolution/superposition methods were also proposed to correct those effects. Nowadays, many commercial treatment planning systems have adopted this algorithm as a dose calculation engine. The purpose of this study is to verify the accuracy of the dose calculated from pencil beam kernel based treatment planning system comparing to Monte Carlo simulations and measurements especially in inhomogeneous region. ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} Mathematical model represents a power system which consists of synchronous machine connected to infinite bus through transmission line. {yields} Power system stabilizer was designed based on optimal pole shifting controller. {yields} The system performances was tested through load disturbances at different operating conditions. {yields} The system performance with the proposed optimal pole shifting controller is compared with the conventional pole placement controller. {yields} The digital simulation results indicated that the proposed controller has a superior performance. -- Abstract: Power system stabilizer based on optimal pole shifting is proposed. An approach for shifting the real parts of the open-loop poles to any desired positions while preserving the imaginary parts is presented. In each step of this approach, it is ...

Energy Technology Data Exchange (ETDEWEB)

Sandia National Laboratories has recently developed two major field test capabilities for unattended ground sensor systems at the Department of energy`s Nevada Test Site (NTS). The first capability utilizes the NTS large area, varied terrain, and intrasite communications systems for testing sensors for detecting and tracking vehicular traffic. Sensor and ground truth data can be collected at either of two secure control centers. This system also includes an automated ground truth capability that consists of differential Global Positioning Satellite (GPS) receivers on test vehicles and live TV coverage of critical road sections. Finally there is a high-speed, secure computer network link between the control centers and the Air Force`s Theater Air Command and Control Simulation Facility in Albuquerque NM. The second capability is Bunker 2-300. It is a facility for evaluating advanced sensor ...

Energy Technology Data Exchange (ETDEWEB)

A Numerical study of beam dynamics was performed for two injector systems for the proposed National High Magnetic Field Laboratory at the Florida State University (FSU) Free Electron Laser (FEL) facility. The first considered a system consisting of a thermionic DC gun, two buncher cavities operated at 260 MHz and 1.3 GHz and two TESLA type cavities, and is very similar to the injector of the ELBE Radiation Source. The second system we studied uses a DC photogun (a copy of JLab FEL electron gun), one buncher cavity operated at 1.3 GHz and two TESLA type cavities. The study is based on PARMELA simulations and takes into account operational experience of both the JLab FEL and the Radiation Source ELBE. The simulations predict the second system will have a much smaller longitudinal emittance. For this reason the DC photo gun based injector is preferred for the ...

CERN Document Server

Deduction modulo is a paradigm which consists in applying the inference rules of a deductive system (such as for instance natural deduction) modulo a rewrite system over terms and propositions. It has been shown that higher-order logic can be simulated into the first-order natural deduction modulo. However, a theorem stated by Goedel and proved by Parikh expresses that proofs in second-order arithmetic may be unboundedly shorter than proofs in first-order arithmetic, even when considering only formulae provable in first-order arithmetic. We investigate how deduction modulo can be used to translate proofs of higher-order arithmetic into first-order proofs without inflating their length. First we show how higher orders can be encoded through a quite simple (finite, terminating, confluent, left-linear) rewrite system. Then, a proof in higher-order arithmetic can be linearly translated into a proof in ...

CERN Document Server

Classical control theory has played a major role in the development of present-day technologies. Likewise, recently developed quantum optimal control methods can be applied to emerging quantum technologies, e.g. quantum information processing -- until now, at the level of a few qubits. However, such methods encounter severe limits when applied to many-body quantum systems: due to the complexity of simulating the latter, existing quantum control algorithms (requiring many iterations to converge) usually fail to yield a desired final state within an acceptable computational time. In contrast, we present here a strategy for controlling a vast range of non-integrable one-dimensional systems that is efficiently applicable to quantum many-body systems, as it can be merged with state-of-the-art tensor network simulation methods like the Density Matrix Renormalization Group. To demonstrate ...

Energy Technology Data Exchange (ETDEWEB)

The average angle of repose and the packing density of random planar heaps of hard disks falling ballistically onto a sticky base line, where the first layer of disks is quenched in random positions, are computed for heaps with a small fixed number of gaps in the base layer. The results we find appear to be almost independent of the size of the heap and they agree with those obtained from computer simulations of large systems.

Energy Technology Data Exchange (ETDEWEB)

This paper presents a series of modeling experiences and problems in simulating the thermal-hydraulic behavior of large PWR steam generators using the RELAP4 and RELAP5 computer codes. Sensitivity studies investigating the heat transfer characteristics of both once-through and U-tube steam generators are discussed. Suggestions and recommendations are given for effective use and potential future improvements of these codes.

Energy Technology Data Exchange (ETDEWEB)

The optimization of ethylene furnace operations using cfd-based simulations has been addressed. The optimization problems have been cast into various formulations: the Multidisciplinary feasible (MDF) approach, the All-At-Once (AAO) approach and the Individual discipline feasible (IDF) approach. These approaches mainly differ in their handling of the state equations as constraints, and hence some of the formulations place restrictions on the methods used to solve the state equations.

Energy Technology Data Exchange (ETDEWEB)

Within the framework of the IEA project Annex 20 - Airflow patters within buildings , an airflow data base was built up as a prototype. It enables airflow profiles, comfort and interior air quality to be studied without having to carry out a 1:1 experiment or having to run an expensive simulation code. The data base contains a number of pre-calculated room airflow profiles with their associated depictions of air quality and risks of drafts for given premises and for different ventilation systems. figs., tabs., refs.

Energy Technology Data Exchange (ETDEWEB)

Large capacity adjustable speed machines (ASMs) at pumped storage power station have been put into full operation and the operating characteristics of ASM have been highly evaluated from the view point of power system operation. The output power (input power) of ASM can be controlled very quickly by applying a vector control scheme to the excitation control. This quick responsive feature of ASM can make it possible to improve the stability of the neighbor sub-power system. For improvement of transient stability, the output power of ASM is reduced very quickly in order to control the acceleration of neighbor generators during and after transmission line faults. For improvement of dynamic stability, the output power of ASM is modulated in accordance with the stabilizing signals detected from the swing of generator rotor or the power flow fluctuation on the transmission line. This paper describes the design concepts and method of control ...

Energy Technology Data Exchange (ETDEWEB)

For light water reactors, loss of coolant is an important point in safety analysis, whereas for gas-cooled reactors the ingress of water into the core region is an incident of safety relevance. The applicability of the computer code system GAMTEREX to pebble beds of spherical high-temperature gas-cooled reactor fuel elements with simulated water ingress is verified by experiment. The measurements were performed at a Siemens-Argonaut reactor, using its ring core as a driver zone for a pebble-bed core in the center of the reactor.

Energy Technology Data Exchange (ETDEWEB)

System-level-operational testing of the ETX-II test-bed electric vehicle is described and the results discussed. Because the traction battery is a major factor in the performance of an electric vehicle, previously reported work on the sodium-sulfur battery designed for use with the ETX-II is reviewed in detail. Chassis dynamometer performance of the test-bed vehicle met or exceeded design goals and compared reasonably well with SIMPLEV computer modeling results. Areas are identified wherein further work is needed to establish a firmer basis for comparison of the simulation and the observed results.

British Library Electronic Table of Contents (United Kingdom)

A modified variable structure interacting multiple model (M-VSIMM) estimator for complex hybrid maneuver target tracking is presented. The M-VSIMM could potentially be applied to fire control systems (FCS) used on warships. Target model groups were designed using 3D dimensional dynamic target models. Optimal model group selection logic was proposed, contrary to the activation and termination logic in the original VSIMM. The system will respond faster with optimal model group selection logic. After performing simulations, the tracking performances of the Kalman, ?-?(-?), VDIE, IMM and M-VSIMM filters were compared under various maneuvering conditions.

International Nuclear Information System (INIS)

The aim of this thesis is the study of new systems devoted to the real time neutron spectrometry and dosimetry. The microelectronics technologies have been used to research a micro system integrating sensor and data processing in real time. The multi range sensor is based on many pair of semiconductor diodes placed face to face and covered by lithium fluoride. The sensor has been designed and its behavior has been simulated. Its operating in reference neutrons beams has been analyzed. (A.L.B.)

Energy Technology Data Exchange (ETDEWEB)

The great advantage of the helical ionization cooling channel (HCC) is its compact structure that enables the fast cooling of muon beam 6-dimensional phase space. This compact aspect requires a high average RF gradient, with few places that do not have cavities. Also, the muon beam is diffuse and requires an RF system with large transverse and longitudinal acceptance. A traveling wave system can address these requirements. First, the number of RF power coupling ports can be significantly reduced compared with our previous pillbox concept. Secondly, by adding a nose on the cell iris, the presence of thin metal foils traversed by the muons can possibly be avoided. We show simulations of the cooling performance of a traveling wave RF system in a HCC, including cavity geometries with inter-cell RF power couplers needed for power propagation.

Energy Technology Data Exchange (ETDEWEB)

In order to suppress resonance vibrations of a rotor-shaft of rotating machinery, a rotor-shaft system elastically supported by ball bearings which are installed in electromagnetic actuators are proposed and the design method of some compensatory circuits in the controller to control the electromagnetic actuators in the system are explained. These actuators are controlled by the analog PID (proportional, integral, and derivative) controller. The compensation for nonlinearity of electromagnetic force, the negative stiffness of electromagnet, and the time lag of the coil current are discussed and the effective control circuits are proposed. The rotor-shaft system is replaced by the equivalent two-degree-of-freedom system and both impulse and frequency responses are numerically simulated for several parameters of PD-controller gain. By applying the principle of dynamic absorbers, ...

Energy Technology Data Exchange (ETDEWEB)

A power system stabilizer based on GMV (Generalized Minimum Variance), one of the adaptive control techniques, is developed to enhance the dynamic performances of a power system using an Artificial Neural Network (ANN). The stabilizer consists of two parts. One part is Inverse Dynamics Neural Networks (IDNN), which is trained to identify the inverse dynamics of controlled plant and used as a one-step ahead controller, or inverse controller. The other part is Adaptive Reference Model (ARM), which prevents excessive controller output. The ARM produces the modified reference value by minimizing a cost function recursively on the assumption that the IDNN perfectly identifies the controlled plant. The IDNN is used in the minimization procedure to calculate the sensitivities. The proposed controller is simulated in a typical one-machine-infinite-bus power system to show its effectiveness to damp sustained low ...

International Nuclear Information System (INIS)

To evaluate the diagnostic performance of commercially available CRT monitors used in a teleradiology system by determining the rate of detection of simulated lung nodules. Three types of CRT monitors were tested in the observation study. They had matrix sizes of 1024 x 768 (16 inches, color), 1024 x 768 (20 inches, color) and 1600 x 1125 (24 inches, black and white). Twenty chest radiographs were obtained by Fuji computed radiography (FCR) of an anthropomorphic chest phantom with ten simulated nodules on its surface. These FCR films were digitized by a film digitizer with 125 DPI (1024 x 1024 matrix sizes) and 12 bit gray scales, and the image data were transferred from Shinshu University Hospital to other hospitals where interpretation was carried out by the radiologists. Ten radiologists of three hospitals were asked to interpret independently both the original FCR films and the images shown on the CRT monitors and to ...

Energy Technology Data Exchange (ETDEWEB)

Three inclined tubular digesters of 13- to 15-litre volume were operated at temperatures between 20 and 30 degrees C with hydraulic retention times of 10-15 days on pig slurry of 10%, 5% and 2.5% Total Solids content. Tube inclination of 16-20 degrees gave no scumming problems. Solids were retained, giving improved gas yields when compared with literature values for conventional stirred digesters. Solids retention is affected by the size of the digester exit and appears to be greater with slurry of low solids content. There is a link between the movement of solids and gas along, and out of, the digester which can lead to unstable oscillating gas production. Tracer studies showed soluble components of the slurry mixed throughout the whole volume of the digester in 25% of the hydraulic retention time or less. Solids moved in well dispersed plug flow. Gas production (both intrinsic and after the addition of acetate) was most rapid in the central section of the digester. Extra-cellular ...

Energy Technology Data Exchange (ETDEWEB)

Biodiesel is derived from triacylglycerides and is produced primarily through transesterification, a chemical reaction of vegetable oils with alcohol, methanol or ethanol. The cost of raw material should be considered since 85 per cent of production cost is related to vegetable oil. The purpose of this study was to evaluate oil expression of sunflower seed. It also examined the sunflower crude oil as a raw material for biodiesel by transesterification in both laboratory and pilot scale studies. Three different biodiesel purification methods were examined. The best result for oil expelling (68.4 per cent) at the experimental stage was obtained for seeds with a moisture content of 6.9 per cent at 25 degrees C and at a screw speed of 114 rpm. For biodiesel production at the laboratory scale, the best result for oil expelling was 87.5 per cent. It was obtained with an ethanol:oil molar ratio of 4.7:1 and with a 4.42 per cent catalyst concentration ...

Energy Technology Data Exchange (ETDEWEB)

Chemical-looping combustion is a promising technology for the combustion of gas or solid fuel with efficient use of energy and inherent separation of CO{sub 2}. Chemical-looping combustion of methane with calcium sulfate as a novel oxygen carrier was conducted in a laboratory scale fixed bed reactor. The effects of reaction temperature, gas flow rate, sample mass, and particle size on reduction reactions were investigated and an optimum operating condition was determined. The results show that this novel oxygen carrier has a high reduction reactivity and stability in a long-time reduction/oxidation test. The conversions of CH{sub 4} increased with a higher temperature, smaller gas flow rate, larger sample mass and smaller particle size. The suitable reaction temperature seems to be around 950 C. Low temperatures lead to a low CH{sub 4} conversion, but a significant SO{sub 2} formation was observed at a higher temperature. The release of SO{sub ...

Energy Technology Data Exchange (ETDEWEB)

This report summarizes the work that was completed in FY 1992 on the program {open_quotes}Technology Development for Concentrating Process Streams.{close_quotes} The purpose of this program is to evaluate and develop evaporator technology for concentrating radioactive waste and product streams such as those generated by the TRUEX process. Concentrating these streams and minimizing the volume of waste generated can significantly reduce disposal costs; however, equipment to concentrate the streams and recycle the decontaminated condensates must be installed. LICON, Inc., is developing an evaporator that shows a great deal of potential for this application. In this report, concepts that need to be incorporated into the design of an evaporator operated in a radioactive environment are discussed. These concepts include criticality safety, remote operation and maintenance, and materials of construction. Both solubility and vapor-liquid equilibrium data are needed to design an effective ...

International Nuclear Information System (INIS)

A scheme for on-line tuning of a fuzzy-logic power system stabilizer is presented. firstly, a fuzzy-logic power system stabilizer is developed using speed deviation and accelerating power as the controller input variables. The inference mechanism of fuzzy-logic controller is represented by a decision table, constructed of linguistic IF-THEN rules. The Linguistic rules are available from experts and the design procedure is based on these rules. It assumed that an exact model of the plant is not available and it is difficult to extract the exact parameters of the power plant. Thus, the design procedure can not be based on an exact model. This is an advantage of fuzzy logic that makes the design of a controller possible without knowing the exact model of the plant. Secondly, two scaling parameters are introduced to tune the fuzzy-logic power system stabilizer. These scaling parameters are the outputs of another fuzzy-logic ...

British Library Electronic Table of Contents (United Kingdom)

In this study, the shear viscosities of wood?plastic composites (WPC)/supercritical CO2 (sc-CO2) solutions at different die temperatures and sc-CO2 contents were measured by a slit die attached on a single-screw extrusion system. A theoretical model based on the Carreau-Yasuda model and Arrhenius equation was then developed to describe the shear-thinning behavior of the WPC/sc-CO2 solution. This model was incorporated into a finite element method software, POLYFLOW, to simulate the pressure and velocity field of WPC/sc-CO2 solution flowing through a foaming die. Based on the simulation results, the pressure drop rate and the location of the supersaturation point were estimated to investigate the cell nucleation. The saturation pressure of sc-CO2 in WPC was determined by a magnetic suspensi...

CERN Document Server

An algorithm for creating synthetic telescope images of Smoothed Particle Hydrodynamics (SPH) density fields is presented, which utilises the adaptive nature of the SPH formalism in full. The imaging process uses Monte Carlo Radiative Transfer (MCRT) methods to model the scattering and absorption of photon packets in the density field, which then exit the system and are captured on a pixelated image plane, creating a 2D image (or a 3D datacube, if the photons are also binned by their wavelength). The algorithm is implemented on the density field directly: no gridding of the field is required, allowing the density field to be described to an identical level of accuracy as the simulations that generated it. Some applications of the method to star and planet formation simulations are presented to illustrate the advantages of this new technique, and suggestions as to how this framework could support a Radiative Equilibrium ...

Energy Technology Data Exchange (ETDEWEB)

In this paper we describe a modelling project to improve a nuclear waste management program in charge of the creation of a new system for the permanent disposal of nuclear waste. SADT (Structural Analysis and Design Technique) is used in order to provide a work-flow description of the functions to be performed by the waste management program. This description is then translated into a number of Coloured Petri Nets (CPN or CP-nets) corresponding to different program functions where additional behavioural inscriptions provide basis for simulation. Each of these CP-nets is simulated to produce timed event charts that are useful for understanding the behaviour of the program functions under different scenarios. Then all the CPN models are linked together to form a single stand-alone application that is useful for validating the interaction and cooperation between the different program functions. A technique for linking ...

International Nuclear Information System (INIS)

This experimental research investigates mixed convection and heat transfer augmentation by gaseous forced jets in a large enclosure, at conditions simulating those of passive containment cooling systems for Gen III+ passively safe reactors. The experiment is designed to measure the key parameters governing heat transfer augmentation by forced jets, and to investigate the effects of geometric factors, including the jet diameter, jet injection orientation, interior structures, and enclosure aspect ratio. The tests cover a variety of injection modes leading to flow configurations of interest for mixing and stratification phenomena in containments under accident conditions. Correlations for heat transfer augmentation by forced jets are developed and compared with experimental data. The characteristic recirculation speed inside the enclosure is introduced and analyzed. Steady stratified temperature distributions are compared with model ...

British Library Electronic Table of Contents (United Kingdom)

Abstract During extracorporeal life support (ECLS), a large portion of the hemodynamic energy is lost to various components of the circuit. Minimization of this loss in the circuit leads to better vital organ perfusion and decreases the risk of systemic inflammation. In this study, we evaluated the hemodynamic properties of differing lengths of tubing in a simulated neonatal ECLS circuit. The neonatal ECLS circuit used in this study included a Capiox Baby RX05 oxygenator (Terumo Corporation, Tokyo, Japan), a Rotaflow centrifugal pump (MAQUET Cardiopulmonary AG, Hirrlingen, Germany), and a heater and cooler unit. An 8 Fr Biomedicus arterial and a 10 Fr Biomedicus venous cannula were connected to the pseudopatient. One fourth inch tubing was used for both the arterial and the venous line. A ...

International Nuclear Information System (INIS)

An electrochemistry model was developed to analyse the J-V characteristics of a Proton Exchange Membrane (PEM) water electrolyzer for hydrogen production. The Butler-Volmer equation and water transport characteristics through electrolyte membrane were employed to simulate the electrode activation over-potential and membrane ohmic over-potential, respectively. The modeling results are found to agree reasonably well with experimental data published in the literature. The parametric simulations show that the ohmic over-potential is relatively small with typical water content in the membrane. Compared with the cathode over-potential, the anode over-potential is more significant and constitutes the major source of voltage loss. The high anode over-potential is due to the relatively slow oxidation kinetics, which is related to anode material property and microstructure. This model can be integrated with a photovoltaic or wind turbine model to predict ...

Energy Technology Data Exchange (ETDEWEB)

When backward time travel through wormholes is taken into account, classical physics loses its determinism and allows simulation of some quantum behaviours. We show how it is possible to simulate a non-local wavefunction reduction-type effect, i.e. we present a mechanical analogy for the collapse of the wavefunction of an entangled state of two removed particles. This situation can be seen as the simplest EPR situation, i.e. the situation where there is just one direction to measure along the spin (or the correlated properties). We present no rigorous results here, just a different point of view about something that is generally thought to be impossible: modelling a quantum indeterministic and non-local behaviour with a mechanical system.

International Nuclear Information System (INIS)

A three-dimensional (3D) thermal-hydraulic model and a numerical procedure for the simulation and analysis of a steady-state, as well as transient operation of nuclear power plant components are presented. A two-fluid approach is applied to modelling of two-phase flow. Thermal-hydraulics of a horizontal steam generator in the WWER 1000 nuclear power plant has been simulated at the full load, steady-state operation. A comparison of the numerical results with data measured at the NPP Novovoronjezh shows good agreement. 3D numerical results can be used in plant design or retrofitting, in nuclear power plant operation and safety analysis and as improvement of existing one-dimensional thermal-hydraulics models of the horizontal steam generator which are assessed by system codes used for the nuclear power plant safety analyses. (author)

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Porosity evolution at reactive interfaces is a key process that governs the evolution and performances of many engineered systems that have important applications in earth and environmental sciences. This is the case, for example, at the interface between cement structures and clays in deep geological nuclear waste disposals. Although in a different transport regime, similar questions arise for permeable reactive barriers used for biogeochemical remediation in surface environments. The COMEDIE project aims at investigating the coupling between transport, hydrodynamics and chemistry when significant variations of porosity occur. The present work focuses on a numerical benchmark used as a design exercise for the future COMEDIE-2D experiment. The use of reactive transport simulation tools like Hytec and Crunch provides predictions of the physico-chemical evolutions that are expected during the future experiments in laboratory. Focus is given in ...