WorldWideScience

Sample records for 3mw power level

  1. 2.3-MW Medium-Voltage, Three-Level Wind Energy Inverter Applying a Unique Bus Structure and 4.5-kV Si/SiC Hybrid Isolated Power Modules: Preprint

    Erdman, W.; Keller, J.; Grider, D.; VanBrunt, E.

    2014-11-01

    A high-efficiency, 2.3-MW, medium-voltage, three-level inverter utilizing 4.5-kV Si/SiC (silicon carbide) hybrid modules for wind energy applications is discussed. The inverter addresses recent trends in siting the inverter within the base of multimegawatt turbine towers. A simplified split, three-layer laminated bus structure that maintains low parasitic inductances is introduced along with a low-voltage, high-current test method for determining these inductances. Feed-thru bushings, edge fill methods, and other design features of the laminated bus structure provide voltage isolation that is consistent with the 10.4-kV module isolation levels. Inverter efficiency improvement is a result of the (essential) elimination of the reverse recovery charge present in 4.5-kV Si PIN diodes, which can produce a significant reduction in diode turn-off losses as well as insulated-gate bipolar transistor (IGBT) turn-on losses. The hybrid modules are supplied in industry-standard 140 mm x 130 mm and 190 mm x 130 mm packages to demonstrate direct module substitution into existing inverter designs. A focus on laminated bus/capacitor-bank/module subassembly level switching performance is presented.

  2. Energy Storage System by Means of Improved Thermal Performance of a 3 MW Grid Side Wind Power Converter

    Qin, Zian; Liserre, Marco; Blaabjerg, Frede;

    2013-01-01

    Wind speed variations make the power of wind turbine system to fluctuate, which could increase the thermal stress of the power converter and reduce its lifetime. In order to relieve this problem, short-term energy storage technologies are applied to improve the thermal performance of a 3 MW grid...... side wind power converter. The cost, weight and cycle life of the energy storage technologies are evaluated based on a typical low speed high turbulence wind profile. In detail, a wind turbine system model is established and its control strategy is illustrated, which is followed by the power control...... method of the energy storage system. Then the conventional thermal evaluation approach is simplified for evaluation with long term wind profile. The case studies are done to address the optimal power size and capacity of the energy storage system by comparing the improvement of the thermal performance...

  3. Reliability Estimation with Uncertainties Consideration for High Power IGBTs in 2.3 MW Wind Turbine Converter System

    Kostandyan, Erik; Ma, Ke

    2012-01-01

    This paper investigates the lifetime of high power IGBTs (insulated gate bipolar transistors) used in large wind turbine applications. Since the IGBTs are critical components in a wind turbine power converter, it is of great importance to assess their reliability in the design phase of the turbine....... Minimum, maximum and average junction temperatures profiles for the grid side IGBTs are estimated at each wind speed input values. The selected failure mechanism is the crack propagation in solder joint under the silicon die. Based on junction temperature profiles and physics of failure model, the...... probabilistic and determinist damage models are presented with estimated fatigue lives. Reliably levels were assessed by means of First Order Reliability Method taking into account uncertainties....

  4. The high-power (3-MW) long-pulse (3-s) radio-frequency system for ion cyclotron resonance heating experiments on TEXTOR

    A multimegajoule ion cyclotron resonance heating (ICRH) experiment was installed on the Torus Experiment for Technology-Oriented Research (TEXTOR) tokamak. The system consists of two independent power lines each designed to generate and launch 1.5 MW of radio-frequency (rf) power into the machine during a 3-s period in the 25- to 29-MHz frequency range. Each power line consists of the following items: a 1.5-MW transmitter, a transmission line system, and an interface linking the transmission line to the antenna of the shielded strip-line type placed along the tokamak's hot liner. Details of the line and antenna diagnostics and data acquisition system together with the subsequent impedance characteristic calculations are given. The rf radiation shielding for the ICRH experiment is explained. The control of the rf setup as a TEXTOR sub-system and the generator pulse control and operation modes are outlined. The antenna loading and power limitation in the presence of plasma and the conditioning procedure are discussed. Finally, the new rf system compatible with the toroidal pump limiter Advanced Limiter Test-II is presented

  5. Characteristics and facilities of a 3MW LEU fuelled TRIGA reactor

    A 3 MW TRIGA reactor fuelled with low enriched uranium having 19.7 % U-235 and 20 wt% Uranium and Zirconium Hydride, has been installed and recently made critical at a research laboratory of the Bangladesh Atomic Energy Commission. This paper describes the basic design, low and high power test results and the facilities of the reactor. The details of the core configuration of the initial criticality with 50 elements and the final core with 100 elements at 3 MW power are discussed. The available experimental facilities are also described briefly. (author)

  6. Thermal Hydraulics Analysis for the 3MW TRIGA MARK-II Research Reactor Under Transient Condition

    Some important thermal hydraulic parameters of the 3 MW TRIGA MARK-II research reactor operating under transient condition were investigated using two computer codes PULTRI and TEMPUL. Major transient parameters, such as, peak power and prompt energy released after pulse, maximum fuel and coolant temperature, surface heat flux, time and radial distribution of temperature within fuel element after pulse, fuel, fuel-cladding gap width variation, etc. were computer and compared with the experimental and operational values as reported in the safety Analysis Report (SAR). It was observed that pulsing of the reactor inserting an excess reactivity of $2.00 shoots the reactor power level to 854.353 MW compared to an experimental value of 852 MW; the maximum fuel temperature corresponding to this peak power was found to be 846.76o C which is much less than the limiting maximum value of fuel temperature of 11500 C as reported in SAR. During a pulse if the film boiling occurs for a peak adiabatic fuel temperature of 1000o C, the calculated outer cladding wall temperature was observed to be 702.390 C compared to a value of 760o C reported in SAR under the same condition. The investigated other results were also found to be in good agreement with the values reported in the SAR. 16 refs., 22 figs. (author)

  7. Operation experience with the 3 MW TRIGA Mark-II research reactor of Bangladesh

    The 3 MW TRIGA Mark-II research reactor of Bangladesh Atomic Energy Commission (BAEC) has been operating since September 14, 1986. The reactor is used for radioisotope production (131I, 99mTc, 46Sc), various R and D activities and manpower training. The reactor has been operated successfully since it's commissioning with the exception of a few reportable incidents. Of these, the decay tank leakage incident of 1997 is considered to be the most significant one. As a result of this incident, reactor operation at full power under forced-convection mode remained suspended for about 4 years. During that time, the reactor was operated at a power level of 250 kW so as to carry out experiments that require lower neutron flux. This was made possible by establishing a temporary by pass connection across the decay tank using local technology. The other incident was the contamination of the Dry Central Thimble (DCT) that took place in March 2002 when a pyrex vial containing 50 g of TeO2 powder got melted inside the DCT. The vial was melted due to high heat generation on its surface while the reactor was operated for 8 hours at 3 MW for trial production of Iodine-131 (131I). A Wet Central Thimble (WCT) was used to replace the damaged DCT in June 2002 such that the reactor operation could be resumed. The WCT was again replaced by a new DCT in June 2003 such that radioisotope production could be continued. A total of 873 irradiation requests (IRs) have been catered for different reactor uses. Out of these, 114 IRs were for radioisotope (RI) production and 759 IRs for different experiments. The total amount of RI produced stands at about 2100 GBq. The total amount of burn-up-fuel is about 6158 MWh. Efforts are on to undertake an ADP project so as to convert the analog console and I and C system of the reactor into digital one. The paper summarizes the reactor operation experiences focusing on troubleshooting, rectification, modification, RI production, various R and D activities

  8. Spent Fuel Management Program in the 3MW TRIGA MARK-II Research Reactor of Bangladesh

    Bangladesh Atomic Energy Commission (BAEC) has been operating a 3 MW TRIGA MARK II research reactor since 1986. The reactor was installed in the campus of the Atomic Energy Research Establishment (AERE) at Savar, Dhaka. It is one of the main nuclear research facilities in the country. The reactor uses TRIGA LEU fuel with uranium content of 20% by weight. The enrichment level of the fuel is 19.7%. The reactor has so far been operated for 7834 hours with a total cumulative burn up of 15898 MWh (662.5 MWd). The total burn up life of the present core is 1200 MWd. The main areas of use are: training of man-power for nuclear power plant applications, radioisotope (RI) production, neutron activation analysis (NAA), neutron radiography (NR) and neutron scattering. The government of Bangladesh has taken decision to establish nuclear power programme in the country. There is an ADP (Annual Development Project) to accomplish necessary activities for construction of medium size nuclear power plant (NPP) in the western zone of the country. Now, with regard to the safe management, storage of spent fuel and disposal of radioactive waste arising from operation of the research reactor and also from the proposed NPP expected to be constructed in future, BAEC is drawing up short and long-term plans and programs. At present, there does not exist any spent fuel element in the reactor facility. It is to be mentioned that Bangladesh is aware of the US DOE’s ‘Take Back Program’ in connection with the research reactor spent fuel of US origin, and is very much interested to take part in this program. The paper presents the current status of handling and storage facilities available for spent fuel and strategy for the safe management of spent fuel to be generated from the research reactor in near future. (author)

  9. Plan for the safe decommissioning of the BAEC 3MW TRIGA MARK-II research reactor

    The 3 MW TRIGA Mark-II research reactor of Bangladesh Atomic Energy Commission (BAEC) has been operating since September 14, 1986. The reactor is used for radioisotope production (131I, 99mTc, 46Sc), various R and D activities, and manpower training. The reactor has been operated successfully since it's commissioning with the exception of a few reportable incidents. Of these, the decay tank leakage incident of 1997 is considered to be the most significant one. As a result of this incident, reactor operation at full power remained suspended for about 4 years. However, the reactor operation was continued during this period at a power level of 250 kW to cater the needs of various R and D groups, which required lower neutron flux for their experiments. This was made possible by establishing a temporary by pass connection across the decay tank using local technology. The reactor was made operational again at full power after successful replacement of the damaged decay tank in August 2001. At present the reactor is operated 5 days a week at a full power level of 3 MW for production of I-131 and R and D purposes. Up to December 2005 total burn-up of the core stands at about 358 Megawatt Days (MWDs). BAEC has planned to increase the production of 131I and as such, the core burn-up is expected to be increased very significantly in the years to come. There is a declaration from the US DOE that all US origin research reactor spent fuel generated within 2006 will be taken away to the USA at their own cost within 2009. But the fuel burn up of the BAEC research reactor is about 6%. So the reactor can operate for about 10-20 years more. An initial decommissioning plan for the BAEC TRIGA reactor and relevant facilities should be established as early as possible as recommended in the IAEA Safety Standards Series No.WS-G-2.1 (Decommissioning of Nuclear Power Plants and Research Reactors - Safety Standards Series No.WS-G-2.1, IAEA, Vienna, 1999). During the design and construction

  10. UPGRADING THE SNS COMPRESSOR RING TO 3 MW

    The initial performance goal for the SNS compressor ring is 1.4 MW with 1.0 GeV linac beam. During the design phase many considerations and provisions have been made to allow progressive increase in power level of the ring, ultimately to 3.0 MW and beyond after years of improvements. The most important provision for future higher power operation is an increase in beam energy from 1.0 to 1.3 GeV. Other possible upgrades covered in this report include ion source current, new stripper foil material, injection and extraction systems, transverse damper, barrier cavity, and electron clearing to avoid e-p instability

  11. The 3 MW ECRH/ECCD transmission and launching system on TORE SUPRA

    The ECRH experiment on TORE SUPRA is designed to inject up to 3 MW of power at 118 GHz using an antenna consisting of six fixed spherical mirrors and three mobile steering mirrors. The position of the mobile mirrors can be varied in real time using two stepper motors for each mobile mirror. In addition to controlling the injection angle, the position of the mobile mirrors also affects the polarisation of the injected wave. Accurate formulae to compute, in real time, the stepper motor positions required to obtain the desired beam injection angles have been derived. Formulae to determine the effect on the wave polarisation, of the actual mobile mirror positions have also been determined. These formulae have been verified by precise laser measurements and by comparison of power deposition calculations and experimental results. (authors)

  12. Nuclear research reactor 0.5 to 3 MW

    This nuclear reactor has been designed for radioisotope production, basic and applied research in reactor physics and nuclear engineering, neutron-beam experimentation, irradiation of various materials and training of scientific and technical personnel. It is located in the 'Production Area' of the Nuclear Technology Center. It is equipped with the necessary facilities for large-scale production of radioisotopes to be used in medicine as well as for other scientific and industrial purposes. In addition, it has a Neutronography Facility and the required equipment to perform Neutron-Activation Analysis. It is an open pool-type reactor, moderated and cooled with light water, fuelled with 20% enriched uranium. Its reflector are graphite and water. It has plate-type fuel elements clad in aluminium. The reactor core is located near the bottom of the demineralized water pool. It includes fuel elements, reflector and sample-holding devices for materials to be irradiated. This kind of configuration, which is widely used in research reactors, provides a high degree of safety since it prevents the core from becoming exposed under any circumstance and does not require any cooling system during reactor shutdown. Power output is between 0.5 to 3 MWTH, with a minimum thermal neutron flux of approx, 1013 n/cm2·sec, at irradiation zone almost with no modifications. Heat extraction is achieved by means of a cooling circuit which comprises two circulation pumps and a plate-type heat exchanger. Final heat dissipation to the atmosphere is performed through another cooling circuit which includes two circulation pumps and a cooling tower. Reactor control is accomplished with five neutron-absorbing rods positioned by means of especially designed elements and governed by the reactor's instrumentation and control system. Should an abnormal situation arise, gravity causes the rods to fall automatically, thus extinguishing the nuclear reaction. The reactor building has a ventilation system

  13. Status of spent fuel in the 3MW BAEC MK-II research reactor facility of Bangladesh

    Bangladesh has been operating a 3 MW TRIGA MARK II research reactor since 1986. The reactor is installed in the campus of the Atomic Energy Research Establishment (AERE) at Savar, which is located about 40 km northwest of Dhaka. It is one of the main nuclear research facilities in the country. The reactor uses TRIGA LEU fuel with uranium content of 20% by weight. The enrichment level of the fuel is 19.7%. So far the reactor has been operated for 5624 hours with a total cumulative burnup (BU) of 10 690 MWh (445 MWd). The main areas of use are: training of man-power for research reactor operation and applications, radioisotope (RI) production, neutron activation analysis (NAA), neutron radiography (NR) and neutron scattering. Radioisotopes produced to date are: I-131, Sc-46 and Tc-99m. Bangladesh is a peace loving country with a strong commitment towards nuclear nonproliferation. Accordingly, it has signed several multilateral and bilateral agreements, protocols, treaties, etc. prevailing in the International Nuclear Non-proliferation regime. Bangladesh has also signed a Nuclear Cooperation Agreement with the USA on 17 September 1981, which facilitated export of nuclear technology from the USA to Bangladesh. The research reactor was procured under the provisions of this agreement. In 2003, the tenure of the Agreement was extended up to 2012. At present, there does not exist any spent fuel element in the reactor facility. However, with the recently undertaken RI production enhancement program, it is expected that the reactor will start generating spent fuels from the year 2012. It is to be mentioned that Bangladesh is aware of the US DOE's 'Take Back Program' in connection with the research reactor spent fuel of US origin, and is very much interested to take part in this program. The paper presents the current status of handling and storage facilities available for spent fuel and strategy for the safe management spent fuel to be generated from the research reactor in

  14. Characterization of blade throw from a 2.3MW horizontal axis wind turbine upon failure

    Sarlak, Hamid; Sørensen, Jens Nørkær

    2015-01-01

    The present work concerns aerodynamics of thrown objects from a 2.3 MW Horizontal Axis Wind Turbine (HAWT), as a consequence of blade failure. The governing set of ordinary differential equations for the flying objects are derived and numerically solved using a 4th order Runge-Kutta time advancing...

  15. Race-track coils for a 3 MW HTS ship motor

    Highlights: • Sumitomo Electric manufactured the HTS field coils for a 3 MW HTS ship motor. • The motor was developed and successfully passed the loading test by Kawasaki Heavy. • We tested and obtained the basic data to evaluate the 20-year durability of coils. - Abstract: Since the discovery of high-temperature superconductivity (HTS), Sumitomo Electric has been developing silver-sheathed Bi2223 superconducting wire and products. Ship propulsion motors are one of the most promising applications of HTS. Sumitomo Electric Industries, Ltd. (SEI) has recently manufactured 24 large racetrack coils, using 70 km long DI-BSCCO wires, for use in a 3 MW HTS motor developed by Kawasaki Heavy Industries, Ltd. (KHI). The 3 MW HTS motor, using our newly developed racetrack coils, has successfully passed the loading test. It is particularly important that the HTS field coils used in ship propulsion motors can withstand the expansive forces repeatedly applied to them. As racetrack type coils have straight sections, the support mechanism they require to withstand expansive forces is very different from that of circular coils. Therefore, we ran tests and obtained the basic data to evaluate the 20-year durability of racetrack coils against the repeatedly applied expansive forces expected in domestic ship propulsion motors

  16. Race-track coils for a 3 MW HTS ship motor

    Ueno, E., E-mail: ueno-eisaku@sei.co.jp; Kato, T.; Hayashi, K.

    2014-09-15

    Highlights: • Sumitomo Electric manufactured the HTS field coils for a 3 MW HTS ship motor. • The motor was developed and successfully passed the loading test by Kawasaki Heavy. • We tested and obtained the basic data to evaluate the 20-year durability of coils. - Abstract: Since the discovery of high-temperature superconductivity (HTS), Sumitomo Electric has been developing silver-sheathed Bi2223 superconducting wire and products. Ship propulsion motors are one of the most promising applications of HTS. Sumitomo Electric Industries, Ltd. (SEI) has recently manufactured 24 large racetrack coils, using 70 km long DI-BSCCO wires, for use in a 3 MW HTS motor developed by Kawasaki Heavy Industries, Ltd. (KHI). The 3 MW HTS motor, using our newly developed racetrack coils, has successfully passed the loading test. It is particularly important that the HTS field coils used in ship propulsion motors can withstand the expansive forces repeatedly applied to them. As racetrack type coils have straight sections, the support mechanism they require to withstand expansive forces is very different from that of circular coils. Therefore, we ran tests and obtained the basic data to evaluate the 20-year durability of racetrack coils against the repeatedly applied expansive forces expected in domestic ship propulsion motors.

  17. Thermal-Hydraulic Analysis of the 3-MW TRIGA MARK-II Research Reactor Under Steady-State and Transient Conditions

    Important thermal-hydraulic parameters of the 3-MW TRIGA MARK-II research reactor operating under both steady-state and transient conditions are reported. Neutronic analyses were performed by using the CITATION diffusion code and the MCNP4B2 Monte Carlo code. The output of CITATION and MCNP4B2 were input to the PARET thermal-hydraulic code to study the steady-state and transient thermal-hydraulic behavior of the reactor. To benchmark the PARET model, data were obtained from different measurements performed by thermocouples in the instrumented fuel (IF) rod during the steady-state operation both under forced- and natural-convection mode and compared with the calculation. The mass flow rates needed for input to PARET were taken from the Final Safety Analysis Report for a downward forced coolant flow equivalent to 3500 gal/min. For natural convection cooling of the reactor, the mass flow rate was generated using the NCTRIGA code. Peak fuel temperatures measured by the thermocouples in the IF rods at different power levels of the TRIGA core were compared with the values calculated by PARET. The axial distribution of the temperatures of the fuel centerline, fuel surface, and the cladding surface in the hot channel were calculated for the reactor operating at the full-power level. Fuel surface heat flux and heat transfer coefficients for the hot channel were also calculated for the reactor operating at the full-power level. The investigated results were found to be in good agreement with the experimental and operational values. The testing of the PARET model calculations through benchmarking the available TRIGA experimental and operational data for pulse-mode operations showed that PARET can successfully be used to analyze the transient behavior of the reactor. Major transient parameters, such as peak power and prompt energy released after pulse, full-width at half-maximum of pulse peak, and maximum fuel centerline temperatures for different fuel elements at different

  18. Criticality and safety parameter studies for upgrading 3 MW TRIGA MARK II research reactor and validation of generated cross section library and computational method

    This study deals with the neutronic and thermal hydraulic analysis of the 3MW TRIGA MARK II research reactor to upgrade it to a higher flux. The upgrading will need a major reshuffling and reconfiguration of the current core. To reshuffle the current core configuration, the chain of NJOY94.10 - WIMSD-5A - CITATION - PARET - MCNP4B2 codes has been used for the overall analysis. The computational methods, tools and techniques, customisation of cross section libraries, various models for cells and super cells, and a lot of associated utilities have been standardised and established/validated for the overall core analysis. Analyses using the 4-group and 7-group libraries of macroscopic cross sections generated from the 69-group WIMSD-5 library showed that a 7-group structure is more suitable for TRIGA calculations considering its LEU fuel composition. The MCNP calculations established that the CITATION calculations and the generated cross section library are reasonably good for neutronic analysis of TRIGA reactors. Results obtained from PARET demonstrated that the flux upgrade will not cause the temperature limit on the fuel to be exceeded. Also, the maximum power density remains, by a substantial margin below the level at which the departure from nucleate boiling could occur. A possible core with two additional irradiation channels around the CT is projected where almost identical thermal fluxes as in the CT are obtained. The reconfigured core also shows 7.25% thermal flux increase in the Lazy Susan. (author)

  19. Index and reference levels for Power Quality

    The JWG C4.07 CIGRE/CIRED have the goal in quantification of index and reference levels of general character for being able to carry out analysis of Power Quality in the actual scenario of market liberalization

  20. Race-track coils for a 3 MW HTS ship motor

    Ueno, E.; Kato, T.; Hayashi, K.

    2014-09-01

    Since the discovery of high-temperature superconductivity (HTS), Sumitomo Electric has been developing silver-sheathed Bi2223 superconducting wire and products. Ship propulsion motors are one of the most promising applications of HTS. Sumitomo Electric Industries, Ltd. (SEI) has recently manufactured 24 large racetrack coils, using 70 km long DI-BSCCO wires, for use in a 3 MW HTS motor developed by Kawasaki Heavy Industries, Ltd. (KHI). The 3 MW HTS motor, using our newly developed racetrack coils, has successfully passed the loading test. It is particularly important that the HTS field coils used in ship propulsion motors can withstand the expansive forces repeatedly applied to them. As racetrack type coils have straight sections, the support mechanism they require to withstand expansive forces is very different from that of circular coils. Therefore, we ran tests and obtained the basic data to evaluate the 20-year durability of racetrack coils against the repeatedly applied expansive forces expected in domestic ship propulsion motors.

  1. Design for a 1.3 MW, 13 MeV Beam Dump for an Energy Recovery Linac

    Sinclair, Charles K; Smith, Colin H

    2005-01-01

    The electron beam exiting an Energy Recovery Linac (ERL) is dumped close to the injection energy. This energy is chosen as low as possible while allowing the beam quality specifications to be met. As ERLs are designed for high average beam current, beam dumps are required to handle high beam power at low energy. Low energy electrons have a short range in practical dump materials, requiring the beam size at the dump face be enlarged to give acceptable power densities and heat fluxes. Cornell University is developing a 100 mA average current ERL as a synchrotron radiation source. The 13 MeV optimum injection energy requires a 1.3 MW beam dump. We present a mature design for this dump, using an array of water-cooled extruded copper tubes. This array is mounted in the accelerator vacuum normal to the beam. Fatigue failure resulting from abrupt thermal cycles associated with beam trips is a potential failure mechanism. We report on designs for a 75 kW, 750 keV tube-cooled beryllium plate dump for electron gun test...

  2. LPGC, Levelized Steam Electric Power Generator Cost

    1 - Description of program or function: LPGC is a set of nine microcomputer programs for estimating power generation costs for large steam-electric power plants. These programs permit rapid evaluation using various sets of economic and technical ground rules. The levelized power generation costs calculated may be used to compare the relative economics of nuclear and coal-fired plants based on life-cycle costs. Cost calculations include capital investment cost, operation and maintenance cost, fuel cycle cost, decommissioning cost, and total levelized power generation cost. These programs can be used for quick analyses of power generation costs using alternative economic parameters, such as interest rate, escalation rate, inflation rate, plant lead times, capacity factor, fuel prices, etc. The two major types of electric generating plants considered are pressurized-water reactor (PWR) and pulverized coal-fired plants. Data are also provided for the Large Scale Prototype Breeder (LSPB) type liquid metal reactor. Costs for plant having either one or two units may be obtained. 2 - Method of solution: LPGC consists of nine individual menu-driven programs controlled by a driver program, MAINPWR. The individual programs are PLANTCAP, for calculating capital investment costs; NUCLOM, for determining operation and maintenance (O and M) costs for nuclear plants; COALOM, for computing O and M costs for coal-fired plants; NFUEL, for calculating levelized fuel costs for nuclear plants; COALCOST, for determining levelized fuel costs for coal-fired plants; FCRATE, for computing the fixed charge rate on the capital investment; LEVEL, for calculating levelized power generation costs; CAPITAL, for determining capitalized cost from overnight cost; and MASSGEN, for generating, deleting, or changing fuel cycle mass balance data for use with NFUEL. LPGC has three modes of operation. In the first, each individual code can be executed independently to determine one aspect of the total

  3. Initial operation and utilization of the Bangladesh 3 Mw TRIGA reactor

    A 3 Mw TRIGA MK-II pulsing type research reactor fuelled with low enrichment uranium having 19.7% U-235 and 20 wt % Uranium, 0.47% Erbium and Zirconium Hydride, has been installed at the Atomic Energy Research Establishment, savar in the last week of October, 1986. This multi-purpose reactor, capable of both steady-state and pulsing operation, has been put into service in several disciplines since its commissioning and presently in operation without any major problem. The paper describes the initial operating experience and the reactor utilization made in several areas including the operator training conducted for the formation of the initial crew for the reactor. (author)

  4. Experience on the refurbishment of the cooling system of the 3 MW TRIGA Mark II research reactor of Bangladesh and the modernization plan of the reactor control console

    The 3 MW TRIGA Mark II research reactor of the Bangladesh Atomic Energy Commission (BAEC) achieved its first criticality on 14 September 1986. Since then, the reactor has been used for manpower training, radioisotope production, and various R and D activities in the field of neutron activation analysis (NAA), neutron radiography (NR), and neutron scattering. Full power reactor operations remained suspended from 1997-2001 when a corrosion leakage problem in the 16N decay tank threatened the integrity of the primary cooling loop. The new tank was installed in 2001 and some modification and upgrades were carried out in the reactor cooling system such that the operational safety of the reactor could be strengthened. The cooling system upgrade mainly included replacement of the fouled shell and tube-type heat exchanger by a new plate-type one, modification of the cooling system piping layout, installation of isolation valves, installation of a chemical injection system for the secondary cooling system, modification of the Emergency Core Cooling System (ECCS), etc. After successful completion of all these modifications, the reactor was made operational again at full power of 3 MW in August 2001. BAEC, the operating organization, is now implementing a government-funded project to replace the old analogue control console of the research reactor with a digital control console. This paper focuses on the modification of the cooling system as well as the I and C system and the upcoming control console upgrade of the 3 MW TRIGA Mark II research reactor of Bangladesh. It also presents short descriptions of major incidents encountered so far in the reactor facility. (author)

  5. Strengthening operational safety of the 3MW TRIGA MK-II research reactor of Bangladesh Atomic Energy Commission through modification and upgrade of its water system

    The 3 MW TRIGA MK-II Research Reactor of Bangladesh Atomic Energy Commission (BAEC) attained its first criticality on 14 September 1986. Since then it has been operated at different power levels for manpower training, various R and D activities and isotope production. However, operation of the reactor had to be suspended temporarily for a number of times because of different types of problems mainly in the water systems of the reactor. The first problem was encountered in January 1990. It was a leakage problem in the suction line of the emergency core cooling system (ECCS). Then in September 1990 a welding joint of the exi-check valve located at the discharge side of one of the two primary pumps failed. As a result primary water started to leak out of the system at a slow rate. These problems were solved locally. However in July 1997 the 32,000 liter capacity N-16 decay tank (made of Type 6061-T6 aluminium alloy) got damaged due to corrosion. As the tank was found not to be repairable, it was decided to replace it by a new one. It was also strongly felt that the water system of the reactor needed to be upgraded such that operational safety of the reactor is strengthened. Keeping this in mind a contract was signed on 14 Jan. 2000 with the original reactor supplier to supply and install a new decay tank by replacing the old one. Under the contract provisions were also kept to upgrade the cooling system. The upgrading program mainly includes replacement of the fouled tube and shell type heat exchanger by a new plate type one, modification of the layout of the cooling pipes, installation of isolation valves, modification of the old ECCS, etc. It is expected that after completion of all these works by May 2001, operational safety of the BAEC TRIGA research reactor will be strengthened significantly. (author)

  6. 3 MW TRIGA Research Reactor facility of BAEC and its Utilization

    Molla, N.I.; Bhuiyan, S.I.; Wadud Mondal, M.A.; Ahmed, F.U.; Islam, M.N.; Hossain, S.M.; Ahmed, K.; Zulquarnain, A.; Abedin, Z. [Bangladesh Atomic Energy Commission, Atomic Energy Research Establishment, Dhaka (Bangladesh)

    1999-08-01

    The paper briefly describes the Utilisation of 3 MW TRIGA Research Reactor of BAEC for neutron beam research, neutron activation analysis are isotope production. It includes the installation of the triple axis neutron spectrometer at the radial piercing beam port and a neutron radiography set-up at the tangential beam port and their uses for material analysis and condensed matter research and material testing. Nuclear and magnetic structures of some ferrites have been studied in powder diffraction method in the double axis mode. SANS technique with double crystal diffraction known as Bonse and Hart's method has been adopted in an experiment with alumina sample. The neutron radiography set-up and its use in the detection of corrosion in alumina have been reported. Determination of arsenic concentration in drinking water from tube well via Instrumental Neutron Activation Analysis and production of radioiodine-131 by dry distillation method are presented. Our experience on the removal of N-16 decay tank because of the leakage of coolant and bringing the research reactor back to operational by-passing the decay tank have been focussed. A possible reconfiguration of the existing TRIGA core, without exceeding the safety margins, providing additional irradiation channel and upgrading the neutron flux for increased radioisotope production has been attempted. Cross section library ENDF/B-VI and JENDL3.2, code NJOY94.10, WIMSD package, 3-D code CITATION, PARET and Monte Carlo code MCNP4B2 have been employed to achieve the objective. (author)

  7. Neutronic Analysis of the 3 MW TRIGA MARK II Research Reactor, Part I: Monte Carlo Simulation

    This study deals with the neutronic analysis of the current core configuration of a 3 MW TRIGA MARK II research reactor at Atomic Energy Research Establishment (AERE), Savar, Dhaka, Bangladesh and validation of the results by benchmarking with the experimental, operational and available Final Safety Analysis Report (FSAR) values. The three-dimensional continuous-energy Monte Carlo code MCNP4C was used to develop a versatile and accurate full-core model of the TRIGA core. The model represents in detail all components of the core with literally no physical approximation. All fresh fuel and control elements as well as the vicinity of the core were precisely described. Continuous energy cross-section data from ENDF/B-VI and S(α, β) scattering functions from the ENDF/B-V library were used. The validation of the model against benchmark experimental results is presented. The MCNP predictions and the experimentally determined values are found to be in very good agreement, which indicates that the Monte Carlo model is correctly simulating the TRIGA reactor. (author)

  8. 3 MW TRIGA Research Reactor facility of BAEC and its Utilization

    The paper briefly describes the Utilisation of 3 MW TRIGA Research Reactor of BAEC for neutron beam research, neutron activation analysis are isotope production. It includes the installation of the triple axis neutron spectrometer at the radial piercing beam port and a neutron radiography set-up at the tangential beam port and their uses for material analysis and condensed matter research and material testing. Nuclear and magnetic structures of some ferrites have been studied in powder diffraction method in the double axis mode. SANS technique with double crystal diffraction known as Bonse and Hart's method has been adopted in an experiment with alumina sample. The neutron radiography set-up and its use in the detection of corrosion in alumina have been reported. Determination of arsenic concentration in drinking water from tube well via Instrumental Neutron Activation Analysis and production of radioiodine-131 by dry distillation method are presented. Our experience on the removal of N-16 decay tank because of the leakage of coolant and bringing the research reactor back to operational by-passing the decay tank have been focussed. A possible reconfiguration of the existing TRIGA core, without exceeding the safety margins, providing additional irradiation channel and upgrading the neutron flux for increased radioisotope production has been attempted. Cross section library ENDF/B-VI and JENDL3.2, code NJOY94.10, WIMSD package, 3-D code CITATION, PARET and Monte Carlo code MCNP4B2 have been employed to achieve the objective. (author)

  9. Low Power Design with High-Level Power Estimation and Power-Aware Synthesis

    Ahuja, Sumit; Shukla, Sandeep Kumar

    2012-01-01

    Low-power ASIC/FPGA based designs are important due to the need for extended battery life, reduced form factor, and lower packaging and cooling costs for electronic devices. These products require fast turnaround time because of the increasing demand for handheld electronic devices such as cell-phones, PDAs and high performance machines for data centers. To achieve short time to market, design flows must facilitate a much shortened time-to-product requirement. High-level modeling, architectural exploration and direct synthesis of design from high level description enable this design process. This book presents novel research techniques, algorithms,methodologies and experimental results for high level power estimation and power aware high-level synthesis. Readers will learn to apply such techniques to enable design flows resulting in shorter time to market and successful low power ASIC/FPGA design. Integrates power estimation and reduction for high level synthesis, with low-power, high-level design; Shows spec...

  10. Thermal hydraulic transient study of 3 MW TRIGA Mark-II research reactor of Bangladesh using the EUREKA-2/RR code

    Highlights: ► Reactor power transition time depends on magnitude and form of reactivity. ► This time also depends on existing reactor power during reactivity insertion. ► Pattern of power transition depends on form of reactivity insertion. ► Doppler’s effect is seen for lower reactivity insertion when reactor power is low. ► EUREKA-2/RR code performs well for RIA and LOFA of TRIGA Mark-II research reactor. - Abstract: EUREKA-2/RR code has been used for the analyses of reactivity insertion accident (RIA) and loss of flow accident (LOFA) of 3 MW TRIGA Mark-II research reactor of Bangladesh. Transient characteristics of different parameters such as core power, fuel temperature, clad temperature, departure from nucleate boiling ratio (DNBR) due to the different form and magnitude of reactivity insertion has been focused. It is found from the analysis that the magnitude of insertion reactivity and the reactor operating power during this insertion impose a total effect on the core safety. Also, transient effects on reactor were studied for 15% loss of flow of the primary coolant. Provided the scram system is available, the reactor is found to shutdown safely in both cases. From these two studies in series, it is seen that EUREKA-2/RR is well suited for the analyses of reactor safety parameters with good approximations.

  11. Microgrid Control Techniques at Power Converter Level

    Valouch, Viktor; Šimek, Petr; Škramlík, Jiří; Tlustý, J.

    Ostrava: VŠB - TU Ostrava, 2013, s. 611-616. ISBN 978-80-248-2988-3. [Electric Power Engineering - EPE 2013. Kouty nad Desnou (CZ), 28.05.2013-30.05.2013] Institutional support: RVO:61388998 Keywords : microgrid * power converter * droop control Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  12. Nuclear power and low level radiation hazards

    Even in the future, nuclear power is expected to contribute less than 1/10th of the present total population exposure to man-made radiation. By the best estimates available, the current health risks of nuclear power generation appear to be much less than those associated with the major alternative sources of energy, with the exception of natural gas which is about equally safe. Uncertainties concerning the radiation risks from nuclear power, from medical x-rays and from the effects of reduced ventillation to conserve heat appear to be less than those associated with estimates of risks from the use of coal and various other sources of energy. This is in part because of the large amount of effort devoted to studies of radiation effects. The benefits in terms of current life expectancy associated with any of the conventional or unconventional methods of power production appear to greatly outweigh the associated current health hazards. (author)

  13. Power Analysis in Two-Level Unbalanced Designs

    Konstantopoulos, Spyros

    2010-01-01

    Previous work on statistical power has discussed mainly single-level designs or 2-level balanced designs with random effects. Although balanced experiments are common, in practice balance cannot always be achieved. Work on class size is one example of unbalanced designs. This study provides methods for power analysis in 2-level unbalanced designs…

  14. Criticality and safety parameter studies for upgrading 3MW TRIGA MARK II research reactor and validation of generated cross section library and computational method

    The neutronic and thermal hydraulic analysis of the 3 MW TRIGA MARK II research reactor to upgrade it is presented. The upgrading will need a major reshuffling and reconfiguration of the current core. To realize this objective, the overall strategy followed is: 1.) generation of problem dependent cross section library from basic Evaluated Nuclear Data Files such as ENDF/B-VI, JENDL3.2 with NJOY94.10+, 2.) use WIMSD-5 package to generate cell constants for all of the materials in the core and its immediate neighborhood, 3.) use CITATION to perform 3-D global analysis of the core to study multiplication factor, neutron flux and power distributions, power peaking factors, temperature reactivity coefficients, etc., 4.) couple output of CITATION with PARET to study thermal hydraulic behavior to predict safety margins, 5.) check the validity of the deterministic codes with the Monte Carlo code MCNP4B2 , and 6.) reshuffle the current core configuration to achieve the desired objectives. The computational methods, tools and techniques, customization of cross section libraries, various models for cells and super cells, and a lot of associated utilities have been standardized and established/validated for the overall core analysis

  15. University students' understanding level about words related to nuclear power

    The authors conducted a survey of university students' understanding level about words related to nuclear power before and after Fukushima Daiichi Power Plant accident, and analyzed the difference between before and after the accident. The results show that university students' understanding level improved after the accident, especially in the case of reported words by mass media. Understanding level of some nuclear power security words which were not reported so much by mass media also improved. That may be caused by rising of people's concern about nuclear power generation after the accident, and there is a possibility that the accident motivated people to access such words via internet, journals, etc. (author)

  16. Application of plasma attenuator for microwave power level control

    V. L. Kofanov

    1967-12-01

    Full Text Available Correlations for the calculation of the circuit back coupling time constant of control power level system using filter which removes signal parasitic amplitude modulation are derived. System is described in which coefficient of the stabilization 250—300 is obtained when changing the input power level is 15—25 db.

  17. Challenges with Tertiary-Level Mechatronic Fluid Power

    Dransfield, Peter; Conrad, Finn

    1996-01-01

    As authors we take the view that mechatronics, as it relates to fluid power, has three levels which we designate as primary, secondary and tertiary. A brief review of the current status of fluid power, hydraulic and pneumatic, and of electronic control of it is presented and discussed. The focus is...... then on tertiary-level mechatronic fluid power and the challenges to it being applied successfully....

  18. Rotational Augmentation on a 2.3 MW Rotor Blade with Thick Flatback Airfoil Cross-Sections: Preprint

    Schreck, S.; Fingersh, L.; Siegel, K.; Singh, M.; Medina, P.

    2013-01-01

    Rotational augmentation was analyzed for a 2.3 MW wind turbine, which was equipped with thick flatback airfoils at inboard radial locations and extensively instrumented for acquisition of time varying surface pressures. Mean aerodynamic force and surface pressure data were extracted from an extensive field test database, subject to stringent criteria for wind inflow and turbine operating conditions. Analyses of these data showed pronounced amplification of aerodynamic forces and significant enhancements to surface pressures in response to rotational influences, relative to two-dimensional, stationary conditions. Rotational augmentation occurrence and intensity in the current effort was found to be consistent with that observed in previous research. Notably, elevated airfoil thickness and flatback design did not impede rotational augmentation.

  19. Reactive Power Impact on Lifetime Prediction of Two-level Wind Power Converter

    Zhou, Dao; Blaabjerg, Frede; Lau, M.; Tonnes, M.

    The influence of reactive power injection on the dominating two-level wind power converter is investigated and compared in terms of power loss and thermal behavior. Then the lifetime of both the partial-scale and full-scale power converter is estimated based on the widely used Coffin-Manson model....... It is concluded that the injection of the reactive power could have serious impact on the power loss and thermal profile, especially at lower wind speed. Furthermore, the introduction of the reactive power could also shorten the lifetime of the wind power converter significantly....

  20. Experimental Study of a Multi Level Overtopping Wave Power Device

    Kofoed, Jens Peter; Hald, Tue; Frigaard, Peter Bak

    2002-01-01

    , compared to only one level, has been evaluated experimentally. From the experimental results, and the performed optimizations based on these, it has been found that the efficiency of a wave power device of the overtopping type can be increased by as much as 76 % by using 5 levels instead of 1. However......, using 5 levels introduces practical problems, and is most probably not economically feasible. It is concluded that it is reasonable to use 2 levels (maybe 3), which can increase the efficiency by 25-40 % compared to using a single level.......Results of experimental investigations of a floating wave energy device called Power Pyramid is presented. The Power Pyramid utilizes reservoirs in multiple levels when capturing wave overtopping and converting it into electrical energy. The effect of capturing the overtopping in multiple levels...

  1. Battery Energy Storage System for PV Output Power Leveling

    Rajkiran Singh; Seyedfoad Taghizadeh; Nadia Mei Lin Tan; Jagadeesh Pasupuleti

    2014-01-01

    Fluctuating photovoltaic (PV) output power reduces the reliability in power system when there is a massive penetration of PV generators. Energy storage systems that are connected to the PV generators using bidirectional isolated dc-dc converter can be utilized for compensating the fluctuating PV power. This paper presents a grid connected energy storage system based on a 2 kW full-bridge bidirectional isolated dc-dc converter and a PWM converter for PV output power leveling. This paper propos...

  2. Power Consideration for Three-Level Growth Models

    Li, Wei; Konstantopoulos, Spyros

    2016-01-01

    The purpose of this study is extend previous methods by Raudenbush and Liu (2001) and Spybrook et al. (2011), and provide methods for power analysis of tests of treatment effects in studies of polynomial change with two levels of nesting (e.g., students and schools) where the treatment is either at the third level (e.g., school intervention) or at…

  3. User's manual for levelized power generation cost using a microcomputer

    Microcomputer programs for the estimation of levelized electrical power generation costs are described. Procedures for light-water reactor plants and coal-fired plants include capital investment cost, operation and maintenance cost, fuel cycle cost, nuclear decommissioning cost, and levelized total generation cost. Programs are written in Pascal and are run on an Apple II Plus microcomputer

  4. Ultrasonic level and temperature sensor for power reactor applications

    An ultrasonic waveguide employing torsional and extensional acoustic waves has been developed for use as a level and temperature sensor in pressurized and boiling water nuclear power reactors. Features of the device include continuous measurement of level, density, and temperature producing a real-time profile of these parameters along a chosen path through the reactor vessel

  5. Computational Analysis of Nuclear Safety Parameters of 3 MW TRIGA Mark-II Research Reactor Based on Evaluated Nuclear Data Libraries JENDL-3.3 and ENDF/B-VII.0

    Khan, Jahirul Haque [Bangladesh Atomic Energy Commission, Dhaka (Bangladesh)

    2013-07-01

    The objective of this study is to explain the main nuclear safety parameters of 3 MW TRIGA Mark-II Research Reactor at AERE, Savar, Dhaka, Bangladesh from the viewpoint of reactor safety and also reactor operator. The most important nuclear reactor physics safety parameters are power distribution, power peaking factors, shutdown margin, control rod worth, excess reactivity and fuel temperature reactivity coefficient. These parameters are calculated using the chain of the computer codes the SRAC-PIJ for cell calculation based on neutron transport theory and the SRAC-CITATION for core calculation based on neutron diffusion equation. To achieve this objective the TRIGA model is developed by the 3-D diffusion code SRAC-CITATION based on the group constants that come from the collision probability transport code SRAC-PIJ. In this study the evaluated nuclear data libraries JENDL-3.3 and ENDF/B-VII.0 are used. The calculated most important reactor physics parameters are compared to the safety analysis report (SAR) values as well as earlier published MCNP results (numerically benchmark). It was found that the calculated results show a good agreement between the said libraries. Besides, in most cases the calculated results reveal a reasonable agreement with the SAR values (by General Atomic) as well as the MCNP results. In addition, this analysis can be used as the inputs for thermal-hydraulic calculations of the TRIGA fresh core in the steady state and pulse mode operation. Because of power peaking factors, power distributions and temperature reactivity coefficients are the most important reactor safety parameters for normal operation and transient safety analysis in research as well as in power reactors. They form the basis for technical specifications and limitations for reactor operation such as loading pattern limitations for pulse operation (in TRIGA). Therefore, this analysis will be very important to develop the nuclear safety parameters data of 3 MW TRIGA Mark

  6. Computational Analysis of Nuclear Safety Parameters of 3 MW TRIGA Mark-II Research Reactor Based on Evaluated Nuclear Data Libraries JENDL-3.3 and ENDF/B-VII.0

    The objective of this study is to explain the main nuclear safety parameters of 3 MW TRIGA Mark-II Research Reactor at AERE, Savar, Dhaka, Bangladesh from the viewpoint of reactor safety and also reactor operator. The most important nuclear reactor physics safety parameters are power distribution, power peaking factors, shutdown margin, control rod worth, excess reactivity and fuel temperature reactivity coefficient. These parameters are calculated using the chain of the computer codes the SRAC-PIJ for cell calculation based on neutron transport theory and the SRAC-CITATION for core calculation based on neutron diffusion equation. To achieve this objective the TRIGA model is developed by the 3-D diffusion code SRAC-CITATION based on the group constants that come from the collision probability transport code SRAC-PIJ. In this study the evaluated nuclear data libraries JENDL-3.3 and ENDF/B-VII.0 are used. The calculated most important reactor physics parameters are compared to the safety analysis report (SAR) values as well as earlier published MCNP results (numerically benchmark). It was found that the calculated results show a good agreement between the said libraries. Besides, in most cases the calculated results reveal a reasonable agreement with the SAR values (by General Atomic) as well as the MCNP results. In addition, this analysis can be used as the inputs for thermal-hydraulic calculations of the TRIGA fresh core in the steady state and pulse mode operation. Because of power peaking factors, power distributions and temperature reactivity coefficients are the most important reactor safety parameters for normal operation and transient safety analysis in research as well as in power reactors. They form the basis for technical specifications and limitations for reactor operation such as loading pattern limitations for pulse operation (in TRIGA). Therefore, this analysis will be very important to develop the nuclear safety parameters data of 3 MW TRIGA Mark

  7. High-level power analysis and optimization techniques

    Raghunathan, Anand

    1997-12-01

    This thesis combines two ubiquitous trends in the VLSI design world--the move towards designing at higher levels of design abstraction, and the increasing importance of power consumption as a design metric. Power estimation and optimization tools are becoming an increasingly important part of design flows, driven by a variety of requirements such as prolonging battery life in portable computing and communication devices, thermal considerations and system cooling and packaging costs, reliability issues (e.g. electromigration, ground bounce, and I-R drops in the power network), and environmental concerns. This thesis presents a suite of techniques to automatically perform power analysis and optimization for designs at the architecture or register-transfer, and behavior or algorithm levels of the design hierarchy. High-level synthesis refers to the process of synthesizing, from an abstract behavioral description, a register-transfer implementation that satisfies the desired constraints. High-level synthesis tools typically perform one or more of the following tasks: transformations, module selection, clock selection, scheduling, and resource allocation and assignment (also called resource sharing or hardware sharing). High-level synthesis techniques for minimizing the area, maximizing the performance, and enhancing the testability of the synthesized designs have been investigated. This thesis presents high-level synthesis techniques that minimize power consumption in the synthesized data paths. This thesis investigates the effects of resource sharing on the power consumption in the data path, provides techniques to efficiently estimate power consumption during resource sharing, and resource sharing algorithms to minimize power consumption. The RTL circuit that is obtained from the high-level synthesis process can be further optimized for power by applying power-reducing RTL transformations. This thesis presents macro-modeling and estimation techniques for switching

  8. Graphene induced bifurcation of energy levels at low input power

    Li, Rujiang; Lin, Shisheng; Liu, Xu; Chen, Hongsheng

    2015-01-01

    We study analytically the energy states in the waveguide system of graphene coated dielectric nanowire based on the explicit form of nonlinear surface conductivity of graphene. The energy levels of different plasmonic modes can be tuned by the input power at the order of a few tenths of mW. The self-focusing behavior and self-defocusing behavior are exhibited in the lower and upper bifurcation branches, respectively, which are separated by a saturation of input power. Moreover, due to the nonlinearity of graphene, the dispersion relations for different input powers evolve to an energy band which is in sharp contrast with the discrete energy level in the limit of zero power input.

  9. Generation of a library for reactor calculations and some applications in core and safety parameter studies of the 3-MW TRIGA MARK-II research reactor

    This paper reports on a data base of the TRIGAP code that is generated for the 3-MW TRIGA MARK-II research reactor in Bangladesh. The library is created using the WIMS-D/4 code. Cross sections are calculated from zero burnup to 37% of initial 235U in 20 burnup steps. The created TRIGAP library is tested through practical calculations and is compared with experimental values or with values in the safety analysis report (SAR). Excess reactivity of the fresh core configuration is measured and determined to be 10.27 dollars, while a value of 10.267 dollars is obtained using the generated library. By choosing burnup steps of 0, 50, 350, and 750, WM · h, the whole operating history is covered. The calculated temperature defect at 1 and 3 MW is 1.15 and 3.59 dollars compared with the experimental value of 1.02 and 3.64 dollars, respectively. The xenon value obtained at 1 and 3 MW is 2.21 and 3.20 dollars, respectively, compared with 3.57 dollars at 3 MW in the SAR. The TRIGAP code with its new library is used for calculating fast and thermal flux distributions close to values from the SAR

  10. Power Constrained High-Level Synthesis of Battery Powered Digital Systems

    Nielsen, Sune Fallgaard; Madsen, Jan

    2003-01-01

    We present a high-level synthesis algorithm solving the combined scheduling, allocation and binding problem minimizing area under both latency and maximum power per clock-cycle constraints. Our approach eliminates the large power spikes, resulting in an increased battery lifetime, a property of...... utmost importance for battery powered embedded systems. Our approach extends the partial-clique partitioning algorithm by introducing power awareness through a heuristic algorithm which bounds the design space to those of power feasible schedules. We have applied our algorithm on a set of dataflow graphs...

  11. Aerobic Capacity and Anaerobic Power Levels of the University Students

    Taskin, Cengiz

    2016-01-01

    The aim of study was to analyze aerobic capacity and anaerobic power levels of the university students. Total forty university students who is department physical education and department business (age means; 21.15±1.46 years for male and age means; 20.55±1.79 years for female in department physical education), volunteered to participate in this…

  12. Battery Energy Storage System for PV Output Power Leveling

    Rajkiran Singh

    2014-01-01

    Full Text Available Fluctuating photovoltaic (PV output power reduces the reliability in power system when there is a massive penetration of PV generators. Energy storage systems that are connected to the PV generators using bidirectional isolated dc-dc converter can be utilized for compensating the fluctuating PV power. This paper presents a grid connected energy storage system based on a 2 kW full-bridge bidirectional isolated dc-dc converter and a PWM converter for PV output power leveling. This paper proposes two controllers: a current controller using the d-q synchronous reference and a phase-shift controller. The main function of the current controller is to regulate the voltage at the high-side dc, so that the voltage ratio of the high-voltage side (HVS with low-voltage side (LVS is equal to the transformer turns ratio. The phase-shift controller is employed to manage the charging and discharging modes of the battery based on PV output power and battery voltage. With the proposed system, unity power factor and efficient active power injection are achieved. The feasibility of the proposed control system is investigated using PSCAD simulation.

  13. Design of megawatt power level heat pipe reactors

    Mcclure, Patrick Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Poston, David Irvin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dasari, Venkateswara Rao [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reid, Robert Stowers [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-12

    An important niche for nuclear energy is the need for power at remote locations removed from a reliable electrical grid. Nuclear energy has potential applications at strategic defense locations, theaters of battle, remote communities, and emergency locations. With proper safeguards, a 1 to 10-MWe (megawatt electric) mobile reactor system could provide robust, self-contained, and long-term power in any environment. Heat pipe-cooled fast-spectrum nuclear reactors have been identified as a candidate for these applications. Heat pipe reactors, using alkali metal heat pipes, are perfectly suited for mobile applications because their nature is inherently simpler, smaller, and more reliable than “traditional” reactors. The goal of this project was to develop a scalable conceptual design for a compact reactor and to identify scaling issues for compact heat pipe cooled reactors in general. Toward this goal two detailed concepts were developed, the first concept with more conventional materials and a power of about 2 MWe and a the second concept with less conventional materials and a power level of about 5 MWe. A series of more qualitative advanced designs were developed (with less detail) that show power levels can be pushed to approximately 30 MWe.

  14. Protoflight photovoltaic power module system-level tests in the space power facility

    Rivera, Juan C.; Kirch, Luke A.

    1989-01-01

    Work Package Four, which includes the NASA-Lewis and Rocketdyne, has selected an approach for the Space Station Freedom Photovoltaic (PV) Power Module flight certification that combines system level qualification and acceptance testing in the thermal vacuum environment: The protoflight vehicle approach. This approach maximizes ground test verification to assure system level performance and to minimize risk of on-orbit failures. The preliminary plans for system level thermal vacuum environmental testing of the protoflight PV Power Module in the NASA-Lewis Space Power Facility (SPF), are addressed. Details of the facility modifications to refurbish SPF, after 13 years of downtime, are briefly discussed. The results of an evaluation of the effectiveness of system level environmental testing in screening out incipient part and workmanship defects and unique failure modes are discussed. Preliminary test objectives, test hardware configurations, test support equipment, and operations are presented.

  15. Refurbishment, Modernization and Ageing Management Program of The 3MW TRIGA Mark-II Research Reactor of Bangladesh

    The 3 MW TRIGA MK-II research reactor of Bangladesh Atomic Energy Commission (BAEC) achieved its first criticality on 14 September 1986. The reactor has been used for manpower training, radioisotope production and various R and D activities in the field of neutron activation analysis, neutron radiography and neutron scattering. Reactor Operation and Maintenance Unit (ROMU) is responsible for operation and maintenance of the research reactor. During the past twenty seven years ROMU carried out several refurbishments, replacement, modification and modernization activities in the reactor facility. The major tasks carried out under refurbishment program were replacement of the corrosion damaged N-16 decay tank by a new one, replacement of the fouled shell and tube type heat exchanger by a plate type one, modification of the shielding arrangements around the N-16 decay tank and ECCS system and solving the radial beam port-1 leakage problem. All of these refurbishment activities were performed under an annual development project (ADP) funded by Bangladesh government. BAEC research reactor (RR) was operated by analogue console system from its commissioning to July, 2011. Old analog based console has been replaced by digital console on June, 2012. Modernization program for the reactor control console due to obsolescence and unavailability of spare parts of I and C system was vital to restore the safe operation of the reactor. Considering these facts, installation of a digital control console and I and C system based on the state-of-the-art digital technology became necessary. Reactor digital console system installation tasks were performed under another ADP funded project by Bangladesh government. Now the reactor is operating with the digital control system. Besides this, the Neutron Radiography (NR) facility has been modernized by the addition of a digital neutron radiography set-up at the tangential beam port. The Neutron Scattering (NS) facility also has been upgraded

  16. Refurbishment, Modernization and Ageing Management Program of The 3MW TRIGA Mark-II Research Reactor of Bangladesh

    Salam, M. A. [Atomic Energy Research Establishment, Dhaka (Bangladesh)

    2013-07-01

    The 3 MW TRIGA MK-II research reactor of Bangladesh Atomic Energy Commission (BAEC) achieved its first criticality on 14 September 1986. The reactor has been used for manpower training, radioisotope production and various R and D activities in the field of neutron activation analysis, neutron radiography and neutron scattering. Reactor Operation and Maintenance Unit (ROMU) is responsible for operation and maintenance of the research reactor. During the past twenty seven years ROMU carried out several refurbishments, replacement, modification and modernization activities in the reactor facility. The major tasks carried out under refurbishment program were replacement of the corrosion damaged N-16 decay tank by a new one, replacement of the fouled shell and tube type heat exchanger by a plate type one, modification of the shielding arrangements around the N-16 decay tank and ECCS system and solving the radial beam port-1 leakage problem. All of these refurbishment activities were performed under an annual development project (ADP) funded by Bangladesh government. BAEC research reactor (RR) was operated by analogue console system from its commissioning to July, 2011. Old analog based console has been replaced by digital console on June, 2012. Modernization program for the reactor control console due to obsolescence and unavailability of spare parts of I and C system was vital to restore the safe operation of the reactor. Considering these facts, installation of a digital control console and I and C system based on the state-of-the-art digital technology became necessary. Reactor digital console system installation tasks were performed under another ADP funded project by Bangladesh government. Now the reactor is operating with the digital control system. Besides this, the Neutron Radiography (NR) facility has been modernized by the addition of a digital neutron radiography set-up at the tangential beam port. The Neutron Scattering (NS) facility also has been upgraded

  17. Radio frequency plasma nitriding of aluminium at higher power levels

    Nitriding of aluminium 2011 using a radio frequency plasma at higher power levels (500 and 700 W) and lower substrate temperature (500 deg. C) resulted in higher AlN/Al2O3 ratios than obtained at 100 W and 575 deg. C. AlN/Al2O3 ratios derived from X-ray photoelectron spectroscopic analysis (and corroborated by heavy ion elastic recoil time of flight spectrometry) for treatments preformed at 100 (575 deg. C), 500 (500 deg. C) and 700 W (500 deg. C) were 1.0, 1.5 and 3.3, respectively. Scanning electron microscopy revealed that plasma nitrided surfaces obtained at higher power levels exhibited much finer nodular morphology than obtained at 100 W

  18. Piloted Mars mission planning: NEP technology and power levels

    This paper examines the strong interrelationship between assumed technology and mission performance requirements for NEP. Recent systems analysis efforts by NASA, DOE, and various contractors are used to project achievable system performance as a function of technological sophistication for two piloted Mars mission applications. Specific mass regimes for each collection of technologies are presented as a function of power level for piloted applications. Low thrust mission analyses are presented which relate these system performance projections to achievable mission performance. Mission performance ''maps'' are constructed which link prime mission figures-of-merit of time and initial mass with system requirements on power level and specific mass, and hence technology. Both opposition and conjunction class piloted Mars missions are presented for the 2016 opportunity, analogous to those proposed in the ''90-Day Study'' and ''Synthesis'' architecture studies. Mass and time breakdowns are presented for 10 MWe piloted and 5 MWe cargo point designs

  19. Criticality and Safety Parameter Studies of a 3-MW TRIGA MARK-II Research Reactor and Validation of the Generated Cross-Section Library and Computational Method

    This study deals with the analysis of some neutronics and safety parameters of the current core of a 3-MW TRIGA MARK-II research reactor and validation of the generated macroscopic cross-section library and calculational techniques by benchmarking with experimental, operational, and available Safety Analysis Report (SAR) values. The overall strategy is: (a) generation of the problem-dependent cross-section library from basic Evaluated Nuclear Data Files such as ENDF/B-VI and JENDL-3.2 with NJOY94.10+, (b) use of the WIMSD-5 package to generate a few-group neutron macroscopic cross section for all of the materials in the core and its immediate neighborhood, (c) use the three-dimensional CITATION code to perform the global analysis of the core, and (d) checking of the validity of the CITATION diffusion code with the MCNP4B2 Monte Carlo code. The ultimate objective is to establish methods for reshuffling the current core configuration to upgrade the thermal flux at irradiation locations for increased isotope production. The computational methods, tools and techniques, customization of cross-section libraries, various models for cells and supercells, and many associated utilities are standardized and established/validated for the overall neutronic analysis. The excess reactivity, neutron flux, power distribution, power peaking factors, determination of the hot spot, and fuel temperature reactivity coefficients αf in the temperature range of 45 to 1000 deg. C are studied. All the analyses are performed using the 4- and 7-group libraries of the macroscopic cross sections generated from the 69-group WIMSD-5 library. The 7-group calculations yield comparatively better agreement with the experimental value of keff and the other core parameters. The CITATION test runs using different cross-section sets based on the different models applied in the WIMSD-5 calculations show a strong influence of those models on the final integral parameter. Some of the cells are specially

  20. A Rotating Speed Controller Design Method for Power Levelling by Means of Inertia Energy in Wind Power Systems

    Qin, Zian; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    frequency domain for power leveling. Moreover, the impact of other parameters on power leveling, including the time constant of maximum power point tracking (MPPT) and the rotor inertia, are also studied. With the proposed optimal design, the power fluctuations are mitigated as much as possible, while the...

  1. Study on emergency action levels for Qinshan Nuclear Power Plant

    Based on Qinshan NPP, the technique scheme and many required considerations in the development of emergency action levels (EALs) for Nuclear Power Plants are discussed in detail, which include the selection of emergency classification systems, the criteria for development of EALs, the determination of initiating conditions (ICs) and EALs, the presentation of EALs (e.g. EALs matrix, emergency classification procedure chart in main control room, etc.), the use of emergency operating procedures (EOPs) and critical safety function status trees (CSFSTs) in emergency classification, etc. (authors)

  2. Low level waste management developments in UK nuclear power stations

    This paper discusses how the UK definition of low-level waste (LLW) as agreed between the Government regulating departments and the nuclear industry differs from that in the US and elsewhere. It is that the material is not suitable for disposal as ordinary refuse and that it has a specific activity level below 12 GBq/te beta-gamma and 4 GBq/te alpha. In other words it generally covers the low activity trash produced by the industry. The LLW produced as a result of power station operations can be grouped as drummable/non-drummable, compactable/non-compactable using low force compaction technology, and as burnable/non-burnable depending on the management practices locally

  3. Technical basis for staffing levels at nuclear power plants

    Shurberg, D.A.; Haber, S.B. [Brookhaven National Lab., Upton, NY (United States); Morisseau, D. [Nuclear Regulatory Commission, Washington, DC (United States)] [and others

    1995-04-01

    The objective of this project is to provide a technical basis for the establishment of criteria for minimum staffing levels of licensed and non-licensed NPP shift personnel. Minimum staffing levels for the purpose of this study, are defined as those necessary for successful accomplishment of all safety and additional functions that must be performed in order for the licensee to meet applicable regulatory requirements. This project involves a multi-faceted approach to the investigation of the issue. Relevant NRC documentation was identified and reviewed. Using the information obtained from this documentation review, a test plan was developed to aid in the collection of further information regarding the adequacy of current shift staffing levels. The test plan addresses three different activities to be conducted to provide information to the NRC for use in the assessment of current minimum staffing levels. The first activity is collection of data related to industry shift staffing practices through site visits to seven nuclear power plants. The second activity is a simulator study, which will use licensed operator crews responding to a simulated event, under two different staffing levels. Finally, workload models will be constructed for both licensed and non-licensed personnel, using a priori knowledge of the simulator scenarios with data resulting from one of the staffing levels studied in the simulator, and the data collected from the site visits. The model will then be validated against the data obtained from the second staffing level studied in the simulator. The validated model can then be used to study the impact of changing staffing-related variables on the plant shift crew`s ability to effectively mitigate an event.

  4. Utilization experience with research reactors of various power levels

    Utilization of research reactor, PARR-1 at the power level of 5 MW, and then at 9 MW, after the up gradation and conversion from highly enriched uranium (HEU) to low enriched uranium (LEU), has been described. In addition, the type of work carried out around a smaller facility, PARR-2, with power rating of 27kW has also been discussed. Utilization of PARR-1 in the area of neutron diffraction, neutron capture studies, radioisotope production, neutron activation analysis, reactor physics, and in reactor controls etc has been illustrated. The benefits derived from the up gradation of the power for neutron diffraction studies, radioisotope production and neutron radiography have been discussed. The problem, which can be handed successfully on PARR-2, include neutron activation analysis, production of short-lived radioisotopes, and experimentation in reactor engineering and physics for training purposes. Suitable methodologies have been developed for the analysis of samples of varied nature using neutron activation technique, and the experience gained has been applied to the analysis of geological, environmental and biological samples and high purity materials. (author)

  5. Maximum allowable power levels in HANARO fuel channels

    HANARO is a light-water-cooled and heavy-water-reflected research reactor designed and operated at a full power of 30 MWth. The compact core is composed of 23 hexagonal and 16 circular flow channels. Each hexagonal flow channel, formed by a hexagonal flow tube, is loaded with a hexagonal fuel bundle which has 36 fuel elements. The circular flow channel formed by a circular flow tube is loaded with a circular fuel bundle which has 18 fuel elements. In the thermalhydraulic design of the HANARO, the design limit values for the three design parameters were determined using the statistical thermal design method. The design basis is that for the normal operation and the operational occurrences, the physical phenomena like as CHF (Critical Heat Flux) or ONB(Onset of Nucleate Boiling) would not occur with the 95% of probability and the 95% confidence level as illustrated in Figure 1. In this paper, the maximum power levels satisfying the design limits were obtained and the safe operational ranges were made for the four different fuel channels

  6. Experience and challenges on safeguards practices and approaches for BAEC 3 MW TRIGA Mk-II research reactor and other establishment of Bangladesh

    the only establishment in the country where nuclear materials are being used. The 3 MW TRIGA Mark-II research reactor of BAEC has been operating since September 14, 1986. The reactor is used for radioisotope production (131I, 99mTc, 46Sc), various R and D activities, manpower training and education. As a facility and material balance area, AERE facilities have been designated by the Agency (IAEA) as BDA-, BD-A and BDZ- respectively. The facilities at AERE which are of concern from safeguards point of view are the 3MW TRIGA Mk-II research reactor and the radioisotope production laboratory. The reactor facility has fuel elements and fission chambers where nuclear materials are used. Where as the radioisotope production laboratory has isotope transfer cask made from depleted uranium. Accounting of nuclear materials is carried out by maintaining and routinely updating several records as recommended by IAEA and standards prescribed/adopted by the Nuclear Safety and Radiation Control Regulations of BAEC. Nuclear fuel was first imported into the country in 1985. Fuels were loaded into the reactor core on 13 September 1986. IAEA safeguards inspectors visited the facility for the first time in 1986. Since then the facility is inspected regularly on annual basis by two or three inspectors at a time. The inventories of nuclear materials at AERE include several kilograms of 19.7% enriched uranium in the form of TRIGA fuels, several kilograms of depleted uranium in the form of shielding for the radioisotope transfer cask and a few grams of 99.3% enriched uranium in the form of fission chambers. A few of the fuels are still fresh and they have been stored in the fresh fuel storage room. Rest of the fuels is loaded into the reactor core. The facility has not yet generated any spent fuel. According to the safety analysis report (SAR), the initial core loading is capable of producing about 1278 megawatt-days of energy. But as of now, the figure for the total cumulative burn-up stands

  7. Management of the high-level nuclear power facilities

    This thesis approaches current issues in the management of the high power nuclear facilities and as such it appears to be important particularly for nuclear power plant operation topics. Of special interest are the failure events entailing possible catastrophic situations. The contents is structured onto ten chapters. The first chapter describes the operation regimes of the nuclear high power facilities. Highlighted here are the thesis scope and the original features of the work. The second chapter deals with operational policies developed in order to ensure the preventive maintenance of the nuclear installations. Also managing structures are described devoted to practical warranting the equipment safety function of non-classical power stations. In the third chapter cases of nuclear accidents are analyzed especially stressing the probabilistic risk and the operation regimes having in view the elimination of catastrophic events. In the fourth and fifth chapters the control of nuclear radiation emission is treated focusing the quality issue of nuclear installations required to avoid hazardous effects at level of nuclear reactor operation stage. At the same time set of operational measures is given here for preventing risks, catastrophes and chaotic situations. The chapter five presents both theoretical and practical approaches of the nuclear reactor core management concerning particularly the fuel testing, the water primary system and the quality of the involved equipment. In the sixth and seventh chapters issues of risk-quality correlations are approached as well as the structure of expert systems for monitoring the operational regimes of nuclear facilities. The efficiency of the power systems with nuclear injection is discussed and some original ideas developed in this work are evidenced in the eighth and ninth chapters. Presented are here both the operational principles and models of raising the efficiency of the interconnected nuclear stations and prices' policy

  8. Indicators for assessing the safety level of nuclear power plants

    Since the political opening of the states of Central and Eastern Europe roughly one decade ago, Western industrialized countries in particular have been striving to achieve sustainable improvements in the safety of nuclear reactors in those countries. One objective of these efforts is to ensure a high level of nuclear safety and safety culture in line with worldwide endeavors. The enlargement of the European Union in the very near future offers an opportunity for reaching this goal in the participating countries. Existing international framework agreements refer to the appropriate safety guidelines. At EU level, the harmonization of nuclear safety standards has been an important topic for years, with specific constructive activities being initiated, e.g., by the industry and by regulatory authorities. Uniform safety standards should not be the basis of proven reviews conducted by the national licensing and supervisory authorities. The objective should be the development of key requirements as framework conditions, irrespective of their practical implementation. They could be applied to any nuclear power plant in an accession country, but likewise to plants in member states, in order to provide an overview of the current safety status of a nuclear power plant and the rules by which it is run. As deriving uniform safety standards is a very expensive and lengthy procedure, the approach shown here identifies six main areas of review for light water reactors (safety systems; integrity of the safety barriers; risk assessment; radiation exposure of the plant personnel and the environment; plant operations management; plant safety) and the associated safety indicators, with reference criteria formulated as concretely as possible. This proposal also lends itself to international individual evaluations of safety levels and could facilitate the review process already under way for the EU candidate countries. (orig.)

  9. Dynamic evaluation of the levelized cost of wind power generation

    Highlights: • Conventional levelized cost of energy is static and does not consider flexibility. • This paper defines a dynamic version by means of stochastic programming. • A penalty for early exercising is proposed to differentiate static and dynamic. • Results show the effects of feed-in tariff support in low wind sites. • Policy implications are derived on the basis of the static and dynamic measures. - Abstract: This paper discusses an alternative computation method of the levelized cost of energy of distributed wind power generators. Unlike in the conventional procedures, it includes time of commencement as an optimization variable. For that purpose, a methodology from Longstaff and Schwartz’s dynamic program for pricing financial American options is derived, which provides the ability to find the optimum time and value while coping with uncertainty revenues from energy sales and variable capital costs. The results obtained from the analysis of wind records of 50 sites entail that the conventional levelized cost of energy can be broken down into an optimum, minimum (time-dependent) value and a penalty for early exercising, which can be employed to define investment strategies and support policies

  10. Temporal variations in Global Seismic Stations ambient noise power levels

    Ringler, A.T.; Gee, L.S.; Hutt, C.R.; McNamara, D.E.

    2010-01-01

    Recent concerns about time-dependent response changes in broadband seismometers have motivated the need for methods to monitor sensor health at Global Seismographic Network (GSN) stations. We present two new methods for monitoring temporal changes in data quality and instrument response transfer functions that are independent of Earth seismic velocity and attenuation models by comparing power levels against different baseline values. Our methods can resolve changes in both horizontal and vertical components in a broad range of periods (∼0.05 to 1,000 seconds) in near real time. In this report, we compare our methods with existing techniques and demonstrate how to resolve instrument response changes in long-period data (>100 seconds) as well as in the microseism bands (5 to 20 seconds).

  11. Retrieval of Intermediate Level Waste at Trawsfyndd Nuclear Power Station

    Wall, S.; Shaw, I.

    2002-02-25

    In 1996 RWE NUKEM Limited were awarded two contracts by BNFL Magnox Generation as part of the decommissioning programme for the Trawsfynydd power station. From the normal operations of the two Magnox reactors, intermediate level waste (ILW) had accumulated on site, this was Miscellaneous Activated Components (MAC) and Fuel Element Debris (FED). The objective of these projects is retrieval of the waste from storage vaults, monitoring, packaging and immobilization in a form suitable for on site storage in the medium term and eventual disposal to a waste repository. The projects involve the design, supply, commissioning and operation of equipment to retrieve, pack and immobilize the waste, this includes recovery from vaults in both reactor and pond locations and final decommissioning and removal of plant from site after completion of waste recovery.

  12. CEA contribution to power plant operation with high burnup level

    High level burnup in PWR leads to investigate again the choices carried out in the field of fuel management. French CEA has studied the economic importance of reshuffling technique, cycle length, discharge burnup, and non-operation period between two cycles. Power plants operators wish to work with increased length cycles of 18 months instead of 12. That leads to control problems because the core reactivity cannot be controlled with the only soluble boron: moderator temperature coefficient must be negative. With such cycles, it is necessary to use burnable poisons and for economic reasons with a low penalty in end of cycle. CEA has studied the use of Gd2O3 mixed with fuel or with inert element like Al2O3. Parametric studies of specific weights, efficacities relatively to the fuel burnup and the fuel enrichment have been carried out. Particular studies of 1 month cycles with Gd2O3 have shown the possibility to control power distribution with a very low reactivity penalty in EOC. In the same time, in the 100 MW PWR-CAP, control reactivity has been made with large use of gadolinia in parallel with soluble boron for the two first cycles

  13. Experience and challenges on safeguards practices and approaches for BAEC 3 MW TRIGA Mk-II research reactor and other establishment of Bangladesh

    Bangladesh is deeply committed to nuclear non-proliferation signing and accesses to different unilateral protocols, agreements and treaties like Nuclear Non-Proliferation Treaty (NPT), Comprehensive Test Ban Treaty (CTBT), Safeguards Agreements, Nuclear Cooperation Agreements with the USA and other countries etc. are the manifestations of such commitment. The first of such agreements, the NPT was signed in August 1979. NPT is a national commitment that the signatory country will not engage in activities related on nuclear detonations. Subsequently a bilateral agreement entitled 'Safeguards Agreements' was signed with the International Atomic Energy Agency (IAEA) in June 1982. This provides for international verification of facilities and balancing of nuclear materials. 3MW TRIGA Mark-II Research Reactor Facility of Bangladesh Atomic Energy Commission (BAEC) is inspected physically by the IAEA Safeguards Inspectors on an annual basis. For this purpose, a subsidiary arrangement was made with the IAEA, which had defined the scope of such verification. Bangladesh has also signed a Nuclear Cooperation Agreement with the USA on September 17, 1981, which facilitated export of nuclear technology from USA to Bangladesh. Bangladesh also signed another bilateral agreement entitled 'Protocol Additional to the Safeguards Agreements' with the IAEA in March 30, 2001. The main purpose of this agreement is to provide the IAEA with information on 'so called dual-purpose materials and facilities' including the front end and back end of the nuclear fuel cycle. Its enforcement required filing of an initial declaration, draft of which has been sent to the Ministry of Science, Information and Communication Technology (MOSICT) for approval and transmittal to IAEA through the office of the permanent mission in Geneva. This protocol till to-date is the highest level of verification under the nonproliferation regime. The commitment of Bangladesh to non-proliferation is adequately reflected

  14. Analysis and core-life calculation of 3 MW Triga Mark II research reactor including effects of central thimble modification

    The principal objective of this study was to formulate an effective optimal fuel management strategy for TRIGA MARK II research reactor at AERE, Savar. The core management study has been performed by utilizing four basic types of information calculated for the reactor: criticality, power peaking, neutron flux and burnup calculation. Reshuffling at 20,000 MWh step gives the longest core life of the reactor which is 64500 MWh. Central thimble modification altered the shape of the flux which increased the core reactivity by c 12 and the core-life by 500 MWh. Besides, the study gives valuable insight into the behaviour of the reactor

  15. Burnup analysis and in-core fuel management study of the 3 MW TRIGA MARK II research reactor

    The principal objective of this study is to formulate an effective optimal fuel management strategy for the TRIGA MARK II research reactor at AERE, Savar. The core management study has been performed by utilizing four basic types of information calculated for the reactor: criticality, power peaking, neutron flux and burnup calculation. This paper presents the results of the burnup calculations for TRIGA LEU fuel elements. The fuel element burnup for approximately 20 years of operation was calculated using the TRIGAP compute code. The calculation is performed in one-dimensional radial geometry in TRIGAP. Inter-comparison of TRIGAP results with other two calculations performed by MVP-BURN and MCNP4C-ORIGEN2.1 show very good agreement. Reshuffling at 20,000 MWh step provides the highest core lifetime of the reactor, which is 64,500 MWh. Besides, the study gives valuable insight into the behaviour of the reactor and will ensure better utilization and operation of the reactor in future

  16. Estimation of radiological doses due to the failure of a single element of a 3 MW (T) TRIGA Mark-II research reactor

    Radiological doses due to the failure of a single fuel element of a 3 MW (t) TRIGA Mark-II Research Reactor was estimated for both anticipated and design basis releases considering hypothetical accident conditions. The noble gas and halogen fission product inventory has been calculated assuming a burn-up of 2000 MWd occurring in 1.8 calendar years. For both of the releases, one hundred percent of the noble gases in the fuel-cladding gap were assumed to release from the fuel element and subsequently transferred directly to the reactor hall and twenty-five percent of the halogens in the fuel-cladding gap were assumed to release from the fuel element (with the remainder assumed to plat out on the relatively cool cladding). For the removal of the fission product gases from the reactor hall to the environment, two mechanisms were considered. These are: (1) removal by the emergency ventilation system through an activated charcoal trap in the event of a design basis release and (2) removal by the normal ventilation system for anticipated release. For the first removal mechanism, the system has been designed with activated charcoal filters having an efficiency of 0% for noble gases and 99 % for halogens. For both the cases, only the bottom one-fifth of the reactor hall volume was assumed to be involved in the air circulation (i.e., the top four-fifths was considered to be stagnant). The dispersion of the escaped fission products to the environment through the stack of the reactor was estimated using a Gaussian plume model and basing on the design parameters of the TRIGA reactor as well as the meteorological data of the site. Total individual doses in the reactor hall as well as in the environment were calculated applying the methodologies described in the IAEA publications with the assumptions as mentioned above. The total dose was regarded as the doses caused by immersion in the radioactive air plume (for both noble gas and halogen), inhaled halogen and the deposited

  17. Power systems: Carbon negative at the regional level

    Bauer, Nico

    2015-03-01

    Modelling of the power system on the west coast of North America shows that including bioenergy with carbon capture and sequestration technologies could enable the region to be carbon negative by 2050.

  18. Draft emergency action level guidelines for nuclear power plants

    This document is provided for interim use during the initial phases of the NRC effort to promptly improve emergency preparedness at operating nuclear power plants. Changes to the document can be expected as experience is gained in its use and public comments are received. Further, the Commission has initiated a rulemaking procedure, now scheduled for completion in January 1930 in the area of Emergency Planning and Preparedness. Additional requirements are to be expected when rulemaking is completed and some modifications to this document may be necessary. Four classes of Emergency Action Levels are established which replace the classes in Regulatory Guide 1.101, each with associated examples of initiating conditions. The classes are: - Notification of Unusual Event; - Alert; - Site Emergency; - General Emergency. The rationale for the notification and alert classes is to provide early and prompt notification of minor events which could lead to more serious consequences given operator error or equipment failure or which might be indicative of more serious conditions which are not yet fully realized. A gradation is provided to assure fuller response preparations for more serious indicators. The site emergency class reflects conditions where some significant releases are likely or are occurring but where a core melt situation is not indicated based on current information. In this situation full mobilization of emergency personnel in tie :near site environs is indicated as well as dispatch of monitoring teams and associated communications. The general emergency class involves actual or imminent substantial core degradation or malting with the potential for loss of containment. The immediate action for this class is sheltering (staying inside) rather thai evacuation until an assessment can be made that (1) an evacuation is indicated and (2) an evacuation, if indicated, can be completed prior to significant release and transport of radioactive material to the affected

  19. Traction Power System Capacity Limitations at Various Traffic Levels

    Abrahamsson, Lars; Söder, Lennart

    2011-01-01

    The aim, and main contribution, of this paper is to propose a fine-tuned fast approximator, based on neural networks, that uses aggregated traction system information as inputs and outputs. This approximator can be used as an investment planning constraint in the optimization. It considers that there is a limit on the intensity of the train traffic, depending on the strength of the power system. In the numerical examples of this paper, the approximator inputs are the power system configuratio...

  20. Stable level and phase control circuits for high power VHF transmitters for RIB applications

    For most applications it is required that the output power level and insertion phase of a high power transmitter remain unchanged against ambient temperature variation and power supply fluctuations. Design schemes for a stable level controller and a phase controller for use in a VHF transmitter that has been indigenously developed for RIB application at VECC is presented in this paper. (author)

  1. On the Problem of Wireless Scheduling with Linear Power Levels

    Tonoyan, Tigran

    2011-01-01

    In this paper we consider the problem of communication scheduling in wireless networks with respect to the SINR(Signal to Interference plus Noise Ratio) constraint in metric spaces. The nodes are assigned linear powers, i.e. for each sender node the power is constant times the path loss between the sender and corresponding receiver. This is the minimal power for a successful transmission. We present a constant factor deterministic approximation algorithm, which works for at least Euclidean fading metrics. Simultaneously we obtain the approximate value of the optimal schedule length with error at most a constant factor. To give an insight into the complexity of the problem, we show that in some metric spaces the problem is NP-hard and cannot be approximated within a factor less than 1.5.

  2. A High Power Density Three-level Parallel Resonant Converter for Capacitor Charging

    Sheng, Honggang

    2009-01-01

    This dissertation proposes a high-power, high-frequency and high-density three-level parallel resonant converter for capacitor charging. DC-DC pulsed power converters are widely used in military and medical systems, where the power density requirement is often stringent. The primary means for reducing the power converter size has been to reduce loss for reduced cooling systems and to increase the frequency for reduced passive components. Three-level resonant converters, which combine the mer...

  3. The advantages and disadvantages of centralized control of air power at operational level

    Arisoy, Uǧur

    2014-05-01

    People do not want to see and hear a war. In today's world, if war is inevitable, the use of air power is seen as the preferable means of conducting operations instead of financially burdensome land battles which are more likely to cause heavy loss of life. The use of Air Power has gained importance in NATO operations in the Post-Cold War era. For example, air power has undertaken a decisive role from the beginning to the end of the operation in Libya. From this point of view, the most important issue to consider is how to direct air power more effectively at operational level. NATO's Core JFAC (Joint Force Air Command) was established in 2012 to control joint air power at operational level from a single center. US had experienced JFAC aproach in the Operation Desert Storm in 1991. UK, France, Germany, Italy and Spain are also directing their air power from their JFAC structures. Joint air power can be directed from a single center at operational level by means of JFAC. JFAC aproach provides complex planning progress of Air Power to be controled faster in a single center. An Air Power with a large number of aircrafts, long range missiles of cutting-edge technology may have difficulties in achieving results unless directed effectively. In this article, directing air power more effectively at operational level has been studied in the framework of directing air power from a single center carried out by SWOT analysis technique. "Directing Air Power at operational level from a single center similar to JFAC-like structure" is compared with "Directing Air Power at operational level from two centers similar to AC (Air Command) + CAOC (Combined Air Operations Center) structure" As a result of this study, it is assessed that directing air power at operational level from a single center would bring effectiveness to the air campaign. The study examines directing air power at operational level. Developments at political, strategic and tactical levels have been ignored.

  4. 49 CFR 393.94 - Interior noise levels in power units.

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Interior noise levels in power units. 393.94... AND ACCESSORIES NECESSARY FOR SAFE OPERATION Miscellaneous Parts and Accessories § 393.94 Interior noise levels in power units. (a) Applicability of this section. The interior noise level...

  5. A DC-DC Converter Efficiency Model for System Level Analysis in Ultra Low Power Applications

    Benton H. Calhoun; Aatmesh Shrivastava

    2013-01-01

    This paper presents a model of inductor based DC-DC converters that can be used to study the impact of power management techniques such as dynamic voltage and frequency scaling (DVFS). System level power models of low power systems on chip (SoCs) and power management strategies cannot be correctly established without accounting for the associated overhead related to the DC-DC converters that provide regulated power to the system. The proposed model accurately predicts the efficiency of induct...

  6. Photovoltaic Shading Testbed for Module-Level Power Electronics

    Deline, C.; Meydbray, J.; Donovan, M.; Forrest, J.

    2012-05-01

    This document describes a repeatable test procedure that attempts to simulate shading situations, as would be experienced by typical residential rooftop photovoltaic (PV) systems. This type of shading test is particularly useful to evaluate the impact of different power conversion setups, including microinverters, DC power optimizers and string inverters, on overall system performance. The performance results are weighted based on annual estimates of shade to predict annual performance improvement. A trial run of the test procedure was conducted with a side by side comparison of a string inverter with a microinverter, both operating on identical 8kW solar arrays. Considering three different shade weighting conditions, the microinverter was found to increase production by 3.7% under light shading, 7.8% under moderate shading, and 12.3% under heavy shading, relative to the reference string inverter case. Detail is provided in this document to allow duplication of the test method at different test installations and for different power electronics devices.

  7. Low power level safety management of Finnish BWR

    Good practices in work coordination and safety management have contributed to short refueling outage duration in Finnish BWR plants. Human and organizational factors are considered especially important in the low paper states, which consist of start-up, shut-down and the outage period itself. This originates from the use of external labour during the outage, the number of both contemporary and sequentially linked human actions and the variety of potential ways the personnel can affect the plant state. While the containment barrier does not exist, more organizational and administrative means have to be used in risk management. To promote the safety further, special studies have been carried out. This paper discusses both the low power mode PSA and the studies of work orientation and competence among the operating staff in Olkiluoto BWR plant. An advanced outage control requires also open-minded consideration of potential risks and the means for their reduction. Good results in low power risk management can be reached only by the involvement of both the plant operating and the maintenance staff. A profound safety management is a prerequisite for safe low power states. (author)

  8. Design of Oil-Quenching Tank for 3 MW Wind Turbine Main Shaft Bearings%3MW风电主轴轴承淬火油槽设计

    邵阳; 马忠超; 姚艳书

    2015-01-01

    The problems existing in heat treatment for main shaft bearings used in 3MW wind turbines are analyzed.The volume of oil-quenching tank for the bearing rings is calculated,and the structure for oil-quenching tank is rede-signed.The hardness of the bearing rings satisfies standard requirement for secondary quenching cooling process during heat treatment by adopting oil-quenching tank with top plug type and side plug type stirrers.%分析3MW风电主轴轴承热处理中存在的问题,计算轴承套圈淬火油槽的体积,重新设计淬火油槽结构,采用顶插式和侧插式组合搅拌器的淬火油槽,使3MW风电主轴轴承在热处理二次淬火冷却过程中硬度达到标准要求。

  9. Power Analysis for Cross Level Mediation in CRTs

    Kelcey, Ben

    2014-01-01

    A common design in education research for interventions operating at a group or cluster level is a cluster randomized trial (CRT) (Bloom, 2005). In CRTs, intact clusters (e.g., schools) are assigned to treatment conditions rather than individuals (e.g., students) and are frequently an effective way to study interventions because they permit…

  10. Robust model-based steam generator level control in nuclear power plant

    Economic feasibility of a power plant requires smooth and uninterrupted plant operation in the face of varying electrical power demand. The feed-water system in a power plant is a major contributor to plant unavailability. The purpose of this paper is to present a general framework for addressing all aspects of this problem and design, analyze and evaluate a water level controller for Steam Generator (SG) and using robust controller design procedure, Linear Quadratic Gaussian with Loop Transfer Recovery, LQG/LTR for low power and high power range. Simulations show that the proposed controller improves transient response of (SG) water level and demonstrate its superiority to existing conventional PI controllers. (author)

  11. Effect of spatial distribution of dissipated power on modeling of SMR BAW resonators at high power levels.

    Tag, Andreas; Bader, Bernhard; Huck, Christian; Karolewski, Dominik; Pitschi, Maximilian; Weigel, Robert; Hagelauer, Amelie

    2015-10-01

    The modeling of bulk acoustic wave resonators at elevated power levels has been improved by taking the spatial distribution of the dominating loss mechanisms into account. The spatial distribution of the dissipated power enables more accurate modeling of the temperature increase caused by the applied power. Thus, it is also possible to more accurately model the frequency shifts of the resonators' impedance curves resulting from the temperature increase caused by the applied power. Simulation and measurement results for the temperatures and impedances of the resonators with different layerstacks at high power loads are presented. The simulation and measurement results are in good agreement, confirming the presented modeling approach. Furthermore, the de-embedding procedure used to obtain vectorial scattering parameters of the resonators during high power loads, the according measurement setup, and the procedure for measuring absolute temperatures by infrared thermography are discussed. PMID:26470048

  12. Low-level radioactive waste processing at nuclear power plants

    This survey was limited to systems and materials used to process waste liquids contaminated with radionuclides. Since the chemical and radiological character of collected liquids may change dramatically, the survey describes waste and cleanup process streams encountered during normal outage or power production conditions. Influents containing specific organic compounds, salts, or solids common to local sources, and the special techniques developed to remove or concentrate these materials are not detailed in this report. The names and phone numbers of the individuals responsible for investigating and solving these problems, however, provides easy access to data which will save time and expense when facing abnormal processing, purchasing, or engineering challenges. The Liquid Radwaste Source Book contains information collected from 31 of 36 BWR's as well as contact information from all licensed commercial units. Since some sites share common radwaste processing facilities, not all units are represented by individual data sheets

  13. Determination of the acoustic source power levels of wind turbines

    Debruijn, A.; Stam, W. J.; Dewolf, W. B.

    To facilitate Wind Energy Conversin System (WECS) licensing, it is recommended to obtain the immission-relevant sound power from the WECS, since this quantity fits into most recommendations for industrial installations. Measurements on small and medium-scale WECS show that rotor rotation speed is a more important parameter than the wind velocity with regard to the radiated noise. An acoustic telescope was used to identify noise sources on two medium-size wind turbines. The mechanical noise from the nacelle is mostly predominant but the trailing edge aerodynamic noise is not negligible. A prediction model for this type of noise, which leads to good agreement with experimental data was developed. A method to suppress turbulence signals around WECS is a set-up with twin microphones, using correlation techniques on both signals.

  14. User instructions for levelized power generation cost codes using an IBM-type PC

    Coen, J.J.; Delene, J.G.

    1989-01-01

    Programs for the calculation of levelized power generation costs using an IBM or compatible PC are described. Cost calculations for nuclear plants and coal-fired plants include capital investment cost, operation and maintenance cost, fuel cycle cost, decommissioning cost, and total levelized power generation cost. 7 refs., 36 figs., 4 tabs.

  15. User instructions for levelized power generation cost codes using an IBM-type PC

    Programs for the calculation of levelized power generation costs using an IBM or compatible PC are described. Cost calculations for nuclear plants and coal-fired plants include capital investment cost, operation and maintenance cost, fuel cycle cost, decommissioning cost, and total levelized power generation cost. 7 refs., 36 figs., 4 tabs

  16. Power levels in office equipment: Measurements of new monitors and personal computers

    Electronic office equipment has proliferated rapidly over the last twenty years and is projected to continue growing in the future. Efforts to reduce the growth in office equipment energy use have focused on power management to reduce power consumption of electronic devices when not being used for their primary purpose. The EPA ENERGY STAR[registered trademark] program has been instrumental in gaining widespread support for power management in office equipment, and accurate information about the energy used by office equipment in all power levels is important to improving program design and evaluation. This paper presents the results of a field study conducted during 2001 to measure the power levels of new monitors and personal computers. We measured off, on, and low-power levels in about 60 units manufactured since July 2000. The paper summarizes power data collected, explores differences within the sample (e.g., between CRT and LCD monitors), and discusses some issues that arise in m etering office equipment. We also present conclusions to help improve the success of future power management programs.Our findings include a trend among monitor manufacturers to provide a single very low low-power level, and the need to standardize methods for measuring monitor on power, to more accurately estimate the annual energy consumption of office equipment, as well as actual and potential energy savings from power management

  17. Analysis of the DNB ratio and the loss-of-flow accident (LOFA) of the 3 MW TRIGA MARK II research reactor

    The PARET code was used to analyze two most important thermal hydraulic design parameters of the 3 MW TRIGA MARK II research reactor. The first design parameters is the DNB (departure from nucleate boiling) ratio, which is defined as the ratio of the critical heat flux to the heat flux achieved in the core and was computed by means of a suitable correlation as defined in PARET code. The reactor core should be designed so as to prevent the DNBR from dropping below a chosen value under a high heat flux transient condition for the most adverse set of mechanical and coolant conditions. Over the length 0.381 m of the hottest channel the DNB ratio varies, starting from 3.8951 to 5.4031, with a minimum of 2.7851. The peak heat flux occurs at the axial center of the fuel elements; therefore the DNB ratio is minimum at this location. The second design parameter is the loss-of-flow accident scenario of the TRIGA reactor. The Bergles-Rohsenow correlation was selected for detecting onset of nucleate boiling, the transition model with the McAdams correlation was included for fully developed two-phase flow, and the Seider-Tate correlation was used for the single-phase forced convection regime. The loss-of-flow transient after a trip time of 4.08 sec at 85% of loss of normal flow for the TRIGA core shows a peak temperature of 709.22 C in the fuel centerline and 131.94 C in the clad and 46.63 C in the coolant exit of the hottest channel. The transient was terminated at 15% of nominal flow after about 48.0 sec. The time at which the reversal of coolant flow starts is about 67.0 sec. (author)

  18. Nuclear power plant personnel entry level qualifications and training

    This paper summarizes the early results and current status of a research program at ORNL which is intended to provide the methods and technical basis for NRC to initiate the use of the Systems Approach to Training (SAT) in the evaluation of training programs and entry level qualifications for NPP control room personnel. The program is an outgrowth of previous studies of simulator hardware and simulator training requirements under the Safety Related Operator Actions Program which recommended adaptation of a systems methodology to development and evaluation of NPP training programs

  19. Nuclear power plant personnel entry level qualifications and training

    Jorgensen, C.C.; Haas, P.M.; Selby, D.L.; Lowry, J.C.

    1983-01-01

    This paper summarizes the early results and current status of a research program at ORNL which is intended to provide the methods and technical basis for NRC to initiate the use of the Systems Approach to Training (SAT) in the evaluation of training programs and entry level qualifications for NPP control room personnel. The program is an outgrowth of previous studies of simulator hardware and simulator training requirements under the Safety Related Operator Actions Program which recommended adaptation of a systems methodology to development and evaluation of NPP training programs.

  20. Optimum design parameter studies on different power level of the small size SFR

    Core characteristics on different power levels were evaluated for technical support to determine the proper power level of the prototype SFR (Sodium cooled Fast Reactor) in Korea. The initial core will be constructed based on U metal fuel due to the insufficient TRU experiment database, and Uranium fuel will be substituted to TRU fuel. The various uranium cores were designed with same cycle length and the number of batches, and the performances of those cores were evaluated to decide the candidate core for each power levels at first. The selected power levels are 50, 75, 100, 125, 150, and 200 MWe. The fuel cost, irradiation time, and irradiation performance were compared among the candidate cores on different power level. As a different way, the core performance was also estimated by increasing the number of batches to reach the limit of fast neutron fluence at each power level. According to the evaluation of studies, the power capacity of the prototype SFR should not be less than 100 MWe from the neutronics viewpoint because the irradiation performance and the fuel economy became worse rapidly with decreasing power level. (author)

  1. ACCOUNTING OF REACTIVE POWER COMPENSATION LEVEL AT PAYMENT CALCULATION OF TECHNOLOGICAL CONSUMPTION (LOSSES OF ELECTRIC POWER FOR ITS TRANSMISSION IN POWER NETWORK

    E. P. Zabello

    2005-01-01

    Full Text Available The method is proposed to make a correction in payment for consumption of reactive energy and power which is attributed to deviation of actual activation energy losses for reactive power compensation from their standard value. It is recommended to calculate standard loss values for every voltage level and actual loss values are to be determined with the help of application of remote electronic accounting means in the current mode of power consumption.

  2. Modular Multi-level converter based HVDC System for Grid Connection of Offshore Wind Power Plant

    Gnanarathna, U.N.; Chaudhary, Sanjay Kumar; Gole, A.M.; Teodorescu, Remus

    2010-01-01

    This paper explores the application of modular multi-level converters (MMC) as a means for harnessing the power from off-shore wind power plants. The MMC consists of a large number of simple voltage sourced converter (VSC) submodules that can be easily assembled into a converter for high-voltage ......This paper explores the application of modular multi-level converters (MMC) as a means for harnessing the power from off-shore wind power plants. The MMC consists of a large number of simple voltage sourced converter (VSC) submodules that can be easily assembled into a converter for high...

  3. Design and Analysis of Multi Level D-STATCOM to Improve the Power Quality

    Dinesh. Badavath,

    2014-01-01

    Full Text Available In the last decade, the electrical power quality issue has been the main concern of the power companies. Power quality is defined as the index which both the delivery and consumption of electric power affect on the performance of electrical apparatus. From a customer point of view, a power quality problem can be defined as any problem is manifested on voltage, current, or frequency deviation that results in power failure. The power electronics progressive, especially in flexible alternating-current transmission system (FACTS and custom power devices, affects power quality improvement. This paper presents an investigation of seven-Level Cascaded H - bridge (CHB Inverter as Distribution Static Compensator (DSTATCOM in Power System (PS for compensation of reactive power and harmonics. The advantages of CHB inverter are low harmonic distortion, reduced number of switches and suppression of switching losses. The DSTATCOM helps to improve the power factor and eliminate the Total Harmonics Distortion (THD drawn from a Non-Liner Diode Rectifier Load (NLDRL. The D-Q reference frame theory is used to generate the reference compensating currents for DSTATCOM while Proportional and Integral (PI control is used for capacitor dc voltage regulation. A CHB Inverter is considered for shunt compensation of a 11 Kv distribution system. Finally a level shifted PWM (LSPWM and phase shifted PWM (PSPWM techniques are adopted to investigate the performance of CHB Inverter. The results are obtained through Matlab/Simulink software package.

  4. Effects of lignocellulosic composition and microwave power level on the gaseous product of microwave pyrolysis

    Agricultural residues are abundant resources to produce renewable energy and valuable chemicals. This study focused on the effects of lignocellulosic composition and microwave power level on the gaseous product of microwave pyrolysis of agricultural residues. When agricultural residues were under microwave radiation within 10 min, the maximum temperatures of approximately 320, 420, and 530 °C were achieved at the microwave power levels of 300, 400, and 500 W, respectively. Gas yield increased with increasing microwave power level, whereas solid and liquid yields decreased. Besides, gaseous products with higher H2 content and higher calorific values can be obtained at higher microwave power levels. In addition to microwave power level, lignocellulosic composition was also an important factor. H2 and CO2 yields increased with increasing hemicellulose content, whereas CH4 and CO yields increased with increasing cellulose content. Four empirical equations were derived to present the contributions of lignocellulosic materials to the yields of gaseous components. - Highlights: • About 530 °C was reached within 10 min at a microwave power level of 500 W. • Gas yield increased with increasing microwave power level. • A high correlation between hemicellulose content and either H2 or CO2 yield. • A high correlation between cellulose content and either CH4 or CO yield. • Empirical equations depict contribution of lignocellulosic content to gas yield

  5. Operating the Irish power system with increased levels of wind power

    Tuohy, A.; Denny, E.; Meibom, Peter;

    2008-01-01

    This paper summarises some of the main impacts of large amounts of wind power installed in the island of Ireland. Using results from various studies performed on this system, it is shown that wind power will impact on all time frames, from seconds to daily planning of the system operation. Results...... from studies examining operation of the system with up to approximately 40% of electricity provided by wind show that some of the most important aspects to be considered include the type of wind turbine technology, the provision of reserve to accommodate wind forecasting error and the method used...

  6. System-level power optimization for wireless multimedia communication power aware computing

    Karri, Ramesh

    2007-01-01

    List of Figures. List of Tables. Preface. 1. Total Power Optimization for Wireless Multimedia Communication; E. Erkip, Xiaoan Ly, Yao Wang, D. Goodman. 2. Energy-Aware TDMA-Based MAC for Sensor Networks; K. Arisha, M. Youssef, M. Younis. 3. Power Aware Packet Routing Control in ad-hoc Wireless Networks; Qilian Liang, N. Neigus. 4. Optimal Node Scheduling for Effective Energy Usage in Sensor Networks; A. Srivastava, J. Sobaje, M. Potkonjak, M. Sarrafzadeh. 5. Energy-Efficient Data Multicast in Multi-Hop Wireless Networks; J.L. Wong, G. Veltri, M. Potkonjak. 6. Low-Energy Software Optimization f

  7. Procedural justice climate and group power distance: an examination of cross-level interaction effects.

    Yang, Jixia; Mossholder, Kevin W; Peng, T K

    2007-05-01

    In this article, the authors extend research on the cross-level effects of procedural justice climate by theorizing and testing its interaction with group power distance. The results indicated that group power distance moderated the relationships between procedural justice climate and individual-level outcomes (organizational commitment and organization-directed citizenship behavior). More specifically, a larger group power distance was found to attenuate the positive cross-level effects of procedural justice climate. Implications for procedural justice climate research are discussed. PMID:17484550

  8. Atmospheric contamination levels in reactor containments of Chooz, Fessenheim and Tihange power plants

    The levels of atmospheric contamination in the french PWR power plants have been studied with the help of measurements results carried out in the french power plant of Fessenheim and in the franco-belgium power plants of Chooz and Tihange. The reached levels, reactor on normal operation and reactor shut-down, are evaluated for the following forms of contamination: noble gases, iodine, aerosols and tritium. The main causes of variation of these levels are also analysed: variations due to primary water activity increasing, variations when intervention with opening of contaminated circuits

  9. Benchmark tests of JENDL-3.3 and ENDF/B-VI data files using Monte Carlo simulation of the 3 MW TRIGA MARK II research reactor

    The three-dimensional continuous-energy Monte Carlo code MNCP4C was used to develop a versatile and accurate full-core model of the 3 MW TRIGA MARK II research reactor at Atomic Energy Research Establishment, Savar, Dhaka, Bangladesh. The model represents in detail all components of the core with literally no physical approximation. All fresh fuel and control elements as well as the vicinity of the core were precisely described. Validation of the newly generated continuous energy cross section data from JENDL-3.3 was performed against some well-known benchmark lattices using MCNP4C and the results were found to be in very good agreement with the experiment and other evaluations. For TRIGA analysis continuous energy section data from JENDL-3.3 and ENDF/B-VI in combination with the JENDL-3.2 and ENDF/B-V data files (for natZr, natMo, natCr, natFe, natNi, natSi, and natMg) at 300K evaluations were used. Full S(α, β) scattering functions from ENDF/B-V for Zr in ZrH, H in ZrH and water molecule, and for graphite were used in both cases. The validation of the model was performed against the criticality and reactivity benchmark experiments of the reactor. The MNCP calculated values for effective multiplication factor keff underestimated 0.0250%Δk/k and 0.2510%Δk/k for control rods critical positions and overestimated 0.2098%Δk/k and 0.0966%Δk/k for all control rods withdrawn positions using JENDL-3.3 and ENDF/B-VI, respectively. The core multiplication factor differs appreciably (∼3.3%) between the no S(α, β) (when temperature representation for free gas treatment is about 300K) and 300K S(α, β) case. However, there is ∼20.0% decrease of thermal neutron flux occurs when the thermal library is removed. Effect of erbium isotope that is present in the TRIGA fuel over the criticality analysis of the reactor was also studied. In addition to the keff values, the well known integral parameters: δ28, δ25, ρ25, and C were calculated and compared for both JENDL3

  10. Application of Back Propagation Neural Network to Drum Level Control in Thermal Power Plants

    Preeti Manke; Sharad Tembhurne

    2012-01-01

    The paper describes the development and testing of a neural network based drum level controller for sub-critical thermal power plant boilers. Experimental data obtained from an operational coal fired power plant (500MW Thermal Power Station, Korba, India) is used to train the neural network. This model proposes a simple training algorithm for a class of nonlinear systems, which enables the neural network to be trained with the output errors of the controlled plant. The only a priori knowledge...

  11. To Strengthen the Career Management for Middle & High-Level Personnel in Power Enterprises

    Jun Ma; Jiaoyan Ma

    2009-01-01

    With the deepening of the power system reform, the management environment of power enterprises has undergone profound changes as well.  The competition advantages of power enterprises have turned from technology and fund to human resources, especially the core talents of enterprises—the middle & high-level personnel.  It is of strategic importance to employ career management to these people in order to exert their human capital advantages and to enhance the core competitive competence of ...

  12. Bidirectional Five-Level Power Processing Interface for Low Voltage Battery Energy Storage System

    Huang, Jain-Yi; Jou, Hurng-Liahng; Wu, Kuen-Der; Lin, You-Si; Wu, Jinn-Chang

    A bidirectional five-level power processing interface for low voltage battery energy storage system (BESS) is developed in this paper. This BESS consists of a bidirectional five-level DC-AC converter, a bidirectional dual boost/buck DC-DC converter and a battery set. This five-level DC-AC converter includes a bidirectional full-bridge converter and a bidirectional dual buck DC-DC converter. The five-level power processing interface can charge power to the battery set form the utility or discharge the power from the battery set to the utility depending on the demanded operation of user. A hardware prototype is developed to verify the performance of this BESS. Experimental results show the performance of the developed BESS is as expected.

  13. Building America Case Study: Photovoltaic Systems with Module-Level Power Electronics

    2015-09-01

    Direct current (DC) power optimizers and microinverters (together known as module-level power electronics, or MLPE) are one of the fastest growing market segments in the solar industry. According to GTM Research in The Global PV Inverter Landscape 2015, over 55% of all residential photovoltaic (PV) installations in the United States used some form of MLPE in 2014.

  14. Automatic controller for steam generator water level during low power operation

    This research proposes a new controller which ensures a satisfactory automatic control for the steam generator water level from low power to full power. It is premised that the current analog control loop is replaced with digital computer control thus expanding the range of possible solutions. The proposed approach is to compensate the level measurement for thermal shrink and swell effects which cause complications in level control during low power operation. A non-linear digital predictor is a part of the controller and is used to estimate shrink and swell effects. The predictor is found to be stable and on-line applicable with micro-processors. The controller is evaluated by calculations in which it controls an existing non-linear digital computer model of a steam generator. For a multi-ramp power increase from low power to full power, the proposed controller shows good performances for the entire range. Water level settles down within 3 min after a single ramp increase (5% power increase in a minute) without any stability problem. Even at very low power, the maximum overshoot is judged to be acceptable. (orig.)

  15. The Level of Power Quality Measurement and Evaluation in A Stone Crusher Plant

    Mustafa ŞEKKELİ

    2009-03-01

    Full Text Available Both electric utilities and end users of electric power are becoming increasingly concerned about the quality of electric power. Quality of electrical energy in the electrical system that is requested continuous power (uninterrupted power, constant frequency and with constant amplitude can be explained by sinusoidal voltage. Deformation of voltage in the form of sinusoidal waveform is explained as a harmonic. Harmonics are most important factors in decreasing quality of energy in the electrical system. In industrial plants, existence of harmocins and voltage drop, causes serious problems both in plant and network. This problem affects the cost. In this study, a power quality measurements are carried out in stone crusher plant. Harmonics and voltage drop has been measured and evaluated with the power analyzer. In the power quality measurements, harmonic level of the plant is not so bad. However, it is recommended that compensation system with harmonic elimination can be established in plant.

  16. System Level Power Management for Embedded Rtos: An Object Oriented Approach

    Ankur Agarwal

    2009-11-01

    Full Text Available Power management systems for embedded devices can be developed in real-time operating system (RTOS or in applications. If power management policies are applied in operating system (OS, then designers and developers will not have to worry about complex power management algorithms and techniques. They can rather concentrate on application development. The OS contains specific and accurate information about the various tasks being executed. An RTOS further has a comprehensive set of power management application programming interfaces (APIs for both device drivers and applications within a power management component. Therefore, it is logical to place policies and algorithms in the OS that can place components not being used into lower power states. This can significantly reduce the system energy consumption. We present here an abstract model of a system power manager (PM, device power managers, and application power managers. We present relationship and interactions of these managers with each other using Unified Modeling Language (UML class diagrams, sequence diagrams and state charts. We recommend that the PM must be implemented at the OS level in any embedded device. We also recommend the interfaces for interactions between PM and the devices power manager, as well as PM and application power manager. Device driver and application developers can easily use this object oriented approach to make the embedded system more power efficient, easy to maintain, and faster to develop.

  17. Maximum core loading of Kartini Reactor at 250 kW of power level

    Maximum core loading of Kartini Reactor at 250 kW of power level. Reevaluation of the safety aspect of Kartini Reactor is currently being performed, for the purpose of increasing the nominal power from 100 to 250 kW. The results of the evaluations will be used to verify the feasibility of the reactor to operate at the proposed power level. One of the important safety parameters which needs to be reevaluated is related to the shutdown capability of the available control rods, which is normally indicated through the parameter of available Shudown Margin (SDM), which is a function of both power level and Core Loading. This paper presents the methodology and the result of determining the Maximum Core Loading of Kartini Reactor at power level of 250 kW. The result indicates that the maximum core loading of Kartini reactor, for 250 kW of Nominal Power is 82 fuel elements, associated with 3.8 $ of available core excess. It is concluded that the negative reactivity of the available control rods is still sufficient to compensate the amount of reactivity produced by the addition of 11 new fuel elements over the minimum requirement for operation at 250 kW of power level

  18. Low Power at Different levels of VLSI Design an clock Distribution Schemes

    Chetan Sharma

    2011-01-01

    Low power chip requirement in the VLSI industry is main considerable field due to the reduction of chip dimension day by day and environmental factors. In this paper various low power techniques at Gate level, Architecture level and different tradeoffs between different clock distribution schemes like as single driver clock scheme and distributed buffers clock scheme are reviewed. Here it is also tried to showing various effects of particular clock distribution scheme such as clock skew, cloc...

  19. Metal clad active fibres for power scaling and thermal management at kW power levels.

    Daniel, Jae M O; Simakov, Nikita; Hemming, Alexander; Clarkson, W Andrew; Haub, John

    2016-08-01

    We present a new approach to high power fibre laser design, consisting of a polymer-free all-glass optical fibre waveguide directly overclad with a high thermal conductivity metal coating. This metal clad active fibre allows a significant reduction in thermal resistance between the active fibre and the laser heat-sink as well as a significant increase in the operating temperature range. In this paper we show the results of a detailed thermal analysis of both polymer and metal coated active fibres under thermal loads typical of kW fibre laser systems. Through several different experiments we present the first demonstration of a cladding pumped aluminium-coated fibre laser and the first demonstration of efficient operation of a cladding-pumped fibre laser at temperatures of greater than 400 °C. Finally, we highlight the versatility of this approach through operation of a passively (radiatively) cooled ytterbium fibre laser head at an output power of 405 W in a compact and ultralight package weighing less than 100 g. PMID:27505822

  20. Performance assessment for the water level control system in steam generator of the nuclear power plant

    Highlights: ► We consider the two PI controller steam generator water level control systems. ► We develop performance assessment methods for plants with stable and unstable zeros. ► The examples show the effectiveness of the proposed method. - Abstract: The steam generator water level control system is the most important components of a nuclear power plant. The operating steam generator water level control system is increasingly recognized as a capital asset that should be routinely maintained and monitored. However, the control loop performance assessment is still an open problem; thus, the performance assessment technology will be brought into the steam generator water level control system in nuclear power plants. Performance assessment methods for the plant with stable and unstable zeros of two PI controller systems are developed at all specific power levels. The numerical examples will demonstrate the effectiveness of the proposed method.

  1. The Level of Difficulty and Discrimination Power of the Basic Knowledge and Skills Examination (EXHCOBA.

    Eduardo Backhoff Escudero

    2000-05-01

    Full Text Available The Basic Knowledge and Skills Examination (EXHCOBA is one of the few great-scale examinations in Mexico which has been publishing its psychometric parameters.  In this paper we describe the  item analysis results, regarding the exam’s difficulty level and discrimination power.  Results show that most of the items have a medium difficulty and a high discrimination power.  They also reveal that the mathematics items have better discrimination power levels than the ones which belong to social science.

  2. A set of fuzzy systems to automate the manual procedures for reactor power level changes

    In this chapter, we describe a set of fuzzy systems which automate the manual part of procedures being used in the reactor operations for PWR-type nuclear power plants. One of the fuzzy systems evaluates the total power defect as a function of the boron concentration and the reactor power level. Others are used to compute the amount of step changes for the control rod as a function of the current rod position and the increment of the total power defect needed for the power level change. Each fuzzy system is either an exact or an approximate representation of the cubic spline interpolation for the corresponding function provided as graphs. The resulting set of fuzzy systems not only improves the efficiency in performing the curve readings but also reduces the interpolation errors involved. (orig.)

  3. Impact of high level penetration of Wind Turbines on Power System Transient Stability

    Kalogiannis, Theodoros; Llano, Enrique Muller; Hoseinzadeh, Bakhtyar;

    2015-01-01

    One of the most relevant aspects in power systems is their reliability and robustness of maintaining the stability under large disturbances. System stability is a crucial aspect to consider when expanding the network, e.g. while increasing the levels of wind power penetration. Wind turbine...... generators differ from the conventional ones in their inertial contribution to the grid, therefore, in most cases the ability of the system to maintain a stable operation is declined. To investigate this, two standard models are designed in PowerFactory software. The first is used to characterize system...... components, the response of the wind turbines and thereupon to validate them, whereas the second is used to estimate the maximum levels of wind power penetration. Those levels mainly depend on the spinning reserve, the inertia of the system and the severity of the event. Rate of change of frequency will...

  4. Plasma Switch for High-Power Active Pulse Compressor

    Hirshfield, Jay L. [Omega-P, Inc.

    2013-11-04

    Results are presented from experiments carried out at the Naval Research Laboratory X-band magnicon facility on a two-channel X-band active RF pulse compressor that employed plasma switches. Experimental evidence is shown to validate the basic goals of the project, which include: simultaneous firing of plasma switches in both channels of the RF circuit, operation of quasi-optical 3-dB hybrid directional coupler coherent superposition of RF compressed pulses from both channels, and operation of the X-band magnicon directly in the RF pulse compressor. For incident 1.2 ?s pulses in the range 0.63 ? 1.35 MW, compressed pulses of peak powers 5.7 ? 11.3 MW were obtained, corresponding to peak power gain ratios of 8.3 ? 9.3. Insufficient bakeout and conditioning of the high-power RF circuit prevented experiments from being conducted at higher RF input power levels.

  5. Optimization of E-DCH channel power ratios to maximize link level efficiency

    Zarco, Carlos Ruben Delgado; Malone, Jaime Tito; Wigard, Jeroen;

    2006-01-01

    For the WCDMA/HSUPA concept, a key to ensuring high spectral efficiency is to correctly adjust the transmission power ratios among the data and control channels. This paper provides optimal values for the power ratio between the Enhanced-Dedicated Physical Data Channel (E-DPDCH) and the Dedicated...... Physical Control Channel (DPCCH) from a Link Efficiency (LE) point of view. LE has been defined as the ratio between the average number of correctly received bits per second and the average total transmitted power. The optimization was carried out by testing different E-DPDCH to DPCCH power ratios in an...... HSUPA link level simulator for different bit rates. This simulator includes Hybrid ARQ (HARQ) and optimal power ratios are extracted for different Retransmission Sequence Number (RSN) targets. For Vehicular-A 30 km/h conditions, the optimal power ratios per code show only minor dependency on the bit...

  6. Scalability of components for kW-level average power few-cycle lasers.

    Hädrich, Steffen; Rothhardt, Jan; Demmler, Stefan; Tschernajew, Maxim; Hoffmann, Armin; Krebs, Manuel; Liem, Andreas; de Vries, Oliver; Plötner, Marco; Fabian, Simone; Schreiber, Thomas; Limpert, Jens; Tünnermann, Andreas

    2016-03-01

    In this paper, the average power scalability of components that can be used for intense few-cycle lasers based on nonlinear compression of modern femtosecond solid-state lasers is investigated. The key components of such a setup, namely, the gas-filled waveguides, laser windows, chirped mirrors for pulse compression and low dispersion mirrors for beam collimation, focusing, and beam steering are tested under high-average-power operation using a kilowatt cw laser. We demonstrate the long-term stable transmission of kW-level average power through a hollow capillary and a Kagome-type photonic crystal fiber. In addition, we show that sapphire substrates significantly improve the average power capability of metal-coated mirrors. Ultimately, ultrabroadband dielectric mirrors show negligible heating up to 1 kW of average power. In summary, a technology for scaling of few-cycle lasers up to 1 kW of average power and beyond is presented. PMID:26974623

  7. User's manual for levelized power generation cost using an IBM PC

    Programs for the estimation of levelized electric power generation costs using the BASIC interpreter on an IBM PC are described. Procedures for light-water reactor plants and coal-fired plants include capital investment cost, operation and maintenance cost, fuel cycle cost, nuclear decommissioning cost, and levelized total generation cost

  8. A control strategy for a three-level unified power quality conditioner

    Monteiro, Luís F. C.; Costa, José C. C.; Aredes, Maurício; Afonso, João L.

    2005-01-01

    In this work a control strategy for a three-level Unified Power Quality Conditioner (UPQC) is introduced. Basically, this control strategy is based on the set of active and non-active (reactive) power definitions in the time domain, which have been proposed by Fryze in the 30´s of the last century. The goal of this work consists in expand this control strategy to deal with three-level converters. The use of three-level converters allows a better performance of the equipment, by reducing...

  9. Wafer-level chip-scale packaging analog and power semiconductor applications

    Qu, Shichun

    2015-01-01

    This book presents a state-of-art and in-depth overview in analog and power WLCSP design, material characterization, reliability, and modeling. Recent advances in analog and power electronic WLCSP packaging are presented based on the development of analog technology and power device integration. The book covers in detail how advances in semiconductor content, analog and power advanced WLCSP design, assembly, materials, and reliability have co-enabled significant advances in fan-in and fan-out with redistributed layer (RDL) of analog and power device capability during recent years. Along with new analog and power WLCSP development, the role of modeling is a key to assure successful package design. An overview of the analog and power WLCSP modeling and typical thermal, electrical, and stress modeling methodologies is also provided. This book also: ·         Covers the development of wafer-level power discrete packaging with regular wafer-level design concepts and directly bumping technology ·    �...

  10. Three-phase power supply, output 60v and 100a, with unit power factor and low RFI level

    João Batista Vieira Júnior

    2003-01-01

    Full Text Available This paper presents a three-phase rectifier, unit power factor, non-dissipative commutation in DC-DC converter and synchronized control in frequency, working with 89% of global efficiency and low level do RFI. The proposed structure allows the operation with high switching frequency. The output voltage is controlled by PWM with a constant frequency. The operation principle, theoretical analysis from DC converter, relevant equations, current balance control technique and experimental results, are shown in this paper.

  11. Nonlinear Power-Level Control of the MHTGR Only with the Feedback Loop of Helium Temperature

    Zhe Dong

    2013-02-01

    Full Text Available Power-level control is a crucial technique for the safe, stable and efficient operation of modular high temperature gas-cooled nuclear reactors (MHTGRs, which have strong inherent safety features and high outlet temperatures. The current power-level controllers of the MHTGRs need measurements of both the nuclear power and the helium temperature, which cannot provide satisfactory control performance and can even induce large oscillations when the neutron sensors are in error. In order to improve the fault tolerance of the control system, it is important to develop a power-level control strategy that only requires the helium temperature. The basis for developing this kind of control law is to give a state-observer of the MHTGR a relationship that only needs the measurement of helium temperature. With this in mind, a novel nonlinear state observer which only needs the measurement of helium temperature is proposed. This observer is globally convergent if there is no disturbance, and has the L2 disturbance attenuation performance if the disturbance is nonzero. The separation principle of this observer is also proven, which denotes that this observer can recover the performance of both globally asymptotic stabilizers and L2 disturbance attenuators. Then, a new dynamic output feedback power-level control strategy is established, which is composed of this observer and the well-built static state-feedback power-level control based upon iterative dissipation assignment (IDA-PLC. Finally, numerical simulation results show the high performance and feasibility of this newly-built dynamic output feedback power-level controller.

  12. US power plant sites at risk of future sea-level rise

    Bierkandt, R.; Auffhammer, M.; Levermann, A.

    2015-12-01

    Unmitigated greenhouse gas emissions may increase global mean sea-level by about 1 meter during this century. Such elevation of the mean sea-level enhances the risk of flooding of coastal areas. We compute the power capacity that is currently out-of-reach of a 100-year coastal flooding but will be exposed to such a flood by the end of the century for different US states, if no adaptation measures are taken. The additional exposed capacity varies strongly among states. For Delaware it is 80% of the mean generated power load. For New York this number is 63% and for Florida 43%. The capacity that needs additional protection compared to today increases by more than 250% for Texas, 90% for Florida and 70% for New York. Current development in power plant building points towards a reduced future exposure to sea-level rise: proposed and planned power plants are less exposed than those which are currently operating. However, power plants that have been retired or canceled were less exposed than those operating at present. If sea-level rise is properly accounted for in future planning, an adaptation to sea-level rise may be costly but possible.

  13. US power plant sites at risk of future sea-level rise

    Unmitigated greenhouse gas emissions may increase global mean sea-level by about 1 meter during this century. Such elevation of the mean sea-level enhances the risk of flooding of coastal areas. We compute the power capacity that is currently out-of-reach of a 100-year coastal flooding but will be exposed to such a flood by the end of the century for different US states, if no adaptation measures are taken. The additional exposed capacity varies strongly among states. For Delaware it is 80% of the mean generated power load. For New York this number is 63% and for Florida 43%. The capacity that needs additional protection compared to today increases by more than 250% for Texas, 90% for Florida and 70% for New York. Current development in power plant building points towards a reduced future exposure to sea-level rise: proposed and planned power plants are less exposed than those which are currently operating. However, power plants that have been retired or canceled were less exposed than those operating at present. If sea-level rise is properly accounted for in future planning, an adaptation to sea-level rise may be costly but possible. (letter)

  14. A DC-DC Converter Efficiency Model for System Level Analysis in Ultra Low Power Applications

    Benton H. Calhoun

    2013-06-01

    Full Text Available This paper presents a model of inductor based DC-DC converters that can be used to study the impact of power management techniques such as dynamic voltage and frequency scaling (DVFS. System level power models of low power systems on chip (SoCs and power management strategies cannot be correctly established without accounting for the associated overhead related to the DC-DC converters that provide regulated power to the system. The proposed model accurately predicts the efficiency of inductor based DC-DC converters with varying topologies and control schemes across a range of output voltage and current loads. It also accounts for the energy and timing overhead associated with the change in the operating condition of the regulator. Since modern SoCs employ power management techniques that vary the voltage and current loads seen by the converter, accurate modeling of the impact on the converter efficiency becomes critical. We use this model to compute the overall cost of two power distribution strategies for a SoC with multiple voltage islands. The proposed model helps us to obtain the energy benefits of a power management technique and can also be used as a basis for comparison between power management techniques or as a tool for design space exploration early in a SoC design cycle.

  15. Multi-spacecraft measurement of anisotropic power levels and scaling in solar wind turbulence

    K. T. Osman; Horbury, T. S.

    2009-01-01

    Measurements by the four Cluster spacecraft in the solar wind are used to determine quantitatively the field-aligned anisotropy of magnetohydrodynamic inertial range turbulence power levels and spectral indexes. We find, using time-lagged second order structure functions, that the spectral index is near 2 around the field-parallel direction, which is consistent with a "critical balance" turbulent cascade. Solar wind fluctuations are found to be anisotropic with power mainly ...

  16. The management of mixed low-level radioactivewaste in the nuclear power industry

    As a result of investigations sponsored by the nuclear power industry, the definition of mixed low-level radioactive waste (mixed waste) in the industry is clarified. A methodology for estimating the annual generation rate of mixed waste is presented and its application to a typical nuclear power plant is illustrated. Effective management practices to minimize the generation of mixed waste are described and strategies to deal with unavoidable mixed waste are identified

  17. Thermal analysis of multi-MW two-level wind power converter

    Zhou, Dao; Blaabjerg, Frede; Mogens, Lau;

    2012-01-01

    In this paper, the multi-MW wind turbine of partial-scale and full-scale two-level power converter with DFIG and direct-drive PMSG are designed and compared in terms of their thermal performance. Simulations of different configurations regarding loss distribution and junction temperature in the...... power device in the whole range of wind speed are presented and analyzed. It is concluded that in both partial-scale and full-scale power converter the most thermal stressed power device in the generator-side converter will have higher mean junction temperature and larger junction temperature...... fluctuation compared to grid-side converter at the rated wind speed. Moreover, the thermal performance of the generator-side converter in the partial-scale power converter becomes crucial around the synchronous operating point and should be considered carefully....

  18. A system-level mathematical model for evaluation of power train performance of load-leveled electric-vehicles

    Purohit, G. P.; Leising, C. J.

    1984-01-01

    The power train performance of load leveled electric vehicles can be compared with that of nonload leveled systems by use of a simple mathematical model. This method of measurement involves a number of parameters including the degree of load leveling and regeneration, the flywheel mechanical to electrical energy fraction, and efficiencies of the motor, generator, flywheel, and transmission. Basic efficiency terms are defined and representative comparisons of a variety of systems are presented. Results of the study indicate that mechanical transfer of energy into and out of the flywheel is more advantageous than electrical transfer. An optimum degree of load leveling may be achieved in terms of the driving cycle, battery characteristics, mode of mechanization, and the efficiency of the components. For state of the art mechanically coupled flyheel systems, load leveling losses can be held to a reasonable 10%; electrically coupled systems can have losses that are up to six times larger. Propulsion system efficiencies for mechanically coupled flywheel systems are predicted to be approximately the 60% achieved on conventional nonload leveled systems.

  19. Estimation of Power Consumption at Behavioral Modeling Level Using SystemC

    Damaševičius Robertas

    2007-01-01

    Full Text Available A successful embedded system design requires thorough domain analysis and design space exploration. The aim is to develop a target system, which implements the prescribed functionality and at the same time meets the design, time, and cost-related constraints. The early evaluation of design characteristics, such as power consumption, allows the user to take advantage of many architectural design options available and to modify the system architecture, if needed. Currently, SystemC is used to model the hardware and software parts of a system at the high level. However, the characteristics of the modeled system are obtained only at the late design stages during physical synthesis. Here, we present a framework for power estimation at the modeling level of a design using macromodels. The SystemC class library is modified and extended with new classes describing the computation of power characteristics of the behavioral-level hardware models.

  20. Architecture-level performance/power tradeoff in network processor design

    CHEN Hong-song; JI Zhen-zhou; HU Ming-zeng

    2007-01-01

    Network processors are used in the core node of network to flexibly process packet streams. With the increase of performance, the power of network processor increases fast, and power and cooling become a bottleneck. Architecture-level power conscious design must go beyond low-level circuit design. Architectural power and performance tradeoff should be considered at the same time. Simulation is an efficient method to design modern network processor before making chip. In order to achieve the tradeoff between performance and power,the processor simulator is used to design the architecture of network processor. Using Netbench, Commubench benchmark and processor simulator-SimpleScalar, the performance and power of network processor are quantitatively evaluated. New performance tradeoff evaluation metric is proposed to analyze the architecture of network processor. Based on the high performance Intel IXP 2800 Network processor configuration, optimized instruction fetch width and speed 、instruction issue width, instruction window size are analyzed and selected. Simulation results show that the tradeoff design method makes the usage of network processor more effectively. The optimal key parameters of network processor are important in architecture-level design. It is meaningful for the next generation network processor design.

  1. Level-one modules library for DSNP: Dynamic Simulator for Nuclear Power-plants

    Saphier, D.

    1978-09-01

    The Dynamic Simulator for Nuclear Power-plants (DSNP) is a system of programs and data sets by which a nuclear power plant or part thereof can be simulated at different levels of sophistication. The acronym DSNP is used interchangeably for the DSNP language, for the DSNP precompiler, for the DSNP libraries, and for the DSNP document generator. The DSNP language is a set of simple block oriented statements, which together with the appropriate data, comprise a simulation of a nuclear power plant. The majority of the DSNP statements will result in the inclusion of a simulated physical module into the program. FORTRAN statements can be inserted with no restrictions among DSNP statements.

  2. Design and operation of 140 GHz gyrotron oscillators for power levels up to 1 MW CW

    Jory, H.; Bier, R.; Craig, L.J.; Felch, K.; Ives, L.; Lopez, N.; Spang, S.

    1986-12-01

    Varian has designed and tested 140 GHz gyrotron oscillators that have generated output powers of 100 kW CW and 200 kW for 1 ms pulses. Upcoming tubes will be designed to operate at power levels of 200 kW CW and ultimately up to 1 MW CW. The important design considerations which are addressed in the higher power tubes include the design of the electron gun, interaction circuit, and output window. These issues will be discussed and the results of the earlier 140 GHz gyrotron work at Varian will be summarized.

  3. Level-one modules library for DSNP: Dynamic Simulator for Nuclear Power-plants

    The Dynamic Simulator for Nuclear Power-plants (DSNP) is a system of programs and data sets by which a nuclear power plant or part thereof can be simulated at different levels of sophistication. The acronym DSNP is used interchangeably for the DSNP language, for the DSNP precompiler, for the DSNP libraries, and for the DSNP document generator. The DSNP language is a set of simple block oriented statements, which together with the appropriate data, comprise a simulation of a nuclear power plant. The majority of the DSNP statements will result in the inclusion of a simulated physical module into the program. FORTRAN statements can be inserted with no restrictions among DSNP statements

  4. Battery Recharging Issue for a Two-Power-Level Flywheel System

    Janaína Gonçalves de Oliveira

    2010-01-01

    Full Text Available A novel battery recharging system for an all-electric driveline comprising a flywheel with a permanent magnet double wound synchronous machine (motor/generator is presented. The double winding enables two voltage levels and two different power levels. This topology supersedes other all-electric drivelines. The battery operates in a low-power regime supplying the average power whereas the flywheel delivers and absorbs power peaks, which are up to a higher order of magnitude. The topology presents new challenges for the power conversion system, which is the focus of this investigation. The main challenge is the control of the power flow to the battery when the vehicle is parked despite the decay of the flywheel machine voltage; which is dependent on its charge state, that is, rotational speed. The design and simulation of an unidirectional DC/DC buck/boost converter for a variable rotational speed flywheel is presented. Conventional power electronic converters are used in a new application, which can maintain a constant current or voltage on the battery side. Successful PI current control has been implemented and simulated, together with the complete closed loop system.

  5. Dynamic Output Feedback Power-Level Control for the MHTGR Based On Iterative Damping Assignment

    Zhe Dong

    2012-06-01

    Full Text Available Because of its strong inherent safety features and high outlet temperature, the modular high temperature gas-cooled nuclear reactor (MHTGR is already seen as the central part of the next generation of nuclear plants. Such power plants are being considered for industrial applications with a wide range of power levels, and thus power-level control is an important technique for their efficient and stable operation. Stimulated by the high regulation performance provided by nonlinear controllers, a novel dynamic output-feedback nonlinear power-level regulator is developed in this paper based on the technique of iterative damping assignment (IDA. This control strategy can provide the L2 disturbance attenuation performance under modeling uncertainty or exterior disturbance, and can also guarantee the globally asymptotic closed-loop stability without uncertainty and disturbance. This newly built control strategy is then applied to the power-level regulation of the HTR-PM plant, and numerical simulation results show both the feasibility and high performance of this newly-built control strategy. Furthermore, the relationship between the values of the parameters and the performance of this controller is not only illustrated numerically but also analyzed theoretically.

  6. Amendment of standard for procedures of level 1 probabilistic risk assessment of nuclear power plants during power operation

    A standard which is intended to provide requirements and methodologies for conducting level 1 probabilistic risk assessment (PRA) was amended. In this standard, PRA is carried out to evaluate the risk of nuclear power plants by evaluating the core damage frequencies due to internal initiating events during power operation. This standard was approved and published by the Atomic Energy Society of Japan (AESJ) on the deliberations at the Subcommittee on Level 1 PRA under the Risk Technical Committee of the AESJ Standards Committee. AESJ formulated and issued this document after deliberation by the Risk Technical Committee and the Standards Committee. PRA of a nuclear power plant is a probabilistic approach for comprehensively and quantitatively assessing plant risk. This involves quantitative analysis of accident scenarios up to core damage and of the further evolution of events after core damage, with careful attention to events that are related to core or fuel damage, finally to arrive at an estimation of event frequencies and consequences. In Japan, PRA has been implemented to evaluate the validity of Accident Management Strategies and the quantitative safety of nuclear power plants in the Periodic Safety Review. Furthermore, in the regulatory area, the Nuclear Regulation Authority, which is the new regulatory authority founded in 2012, intends to utilize PRA in their new safety regulation positively. As the validity of PRA has come to be accepted, preservation of the quality and transparency of PRA has become important issues. Recognizing that preparation of a standard for PRA procedure is effective in addressing these issues, the AESJ standards committee is preparing a procedures guide for nuclear facilities. As described above, this standard replaces the 2008 issue - A Standard for Procedures of Probabilistic Safety Assessment of Nuclear Power Plants during Power Operation (Level 1 PSA):2008 - of the same standard. We decided to make this amendment because five

  7. Decentralized load frequency control on each power plant. Hatsudensho level ni okeru bunsangata fuka shuhasu seigyo

    Tanaka, E.; Hasegawa, J. (HOkkaido Universtiy, Sapporo (Jpaan))

    1991-02-20

    Because of relatively decreasing hydraulic power plants, it becomes difficult to secure an electric power capacity needed for load frequency control of the electric power system. Accordingly, application is studied of the modern control theory based on a state equation instead of the classic control theory. To improve control characteristic by transmitting as little information as possible, decentralized control on each power plant level is studied and applied to a model. The following is a summarized conclusion: By detecting by an integral compensator and controlling variables which are equal to voltage phase angle deviations, frequency deviations or interchange power deviations can be controlled without information on interconnected-power-line tide deviations or interchange power deviations. Designing and practical operation of this system are easy because the control system is structured by the information including frequency deviations only from each power plant. Moreover, if some state variables are not available, the control system can be designed with a dynamic compensator. 6 refs., 4 figs., 2 tabs.

  8. Method for Calculating CO2 Emissions from the Power Sector at the Provincial Level in China

    MA Cui-Mei; GE Quan-Sheng

    2014-01-01

    Based on the detailed origins of each province’s electricity consumption, a new method for calculating CO2 emissions from the power sector at the provincial level in China is proposed. With this so-called consumer responsibility method, the emissions embodied in imported electricity are calculated with source-specific emission factors. Using the new method, we estimate CO2 emissions in 2005 and 2010. Compared with those derived from the producer responsibility method, the power exporters’ emissions decreased sharply. The emissions from the power sector in Inner Mongolia, the largest power exporter of China, decreased by 109 Mt in 2010. The value is equivalent to those from Shaanxi’s power production and Canada’s power and heat production. In contrast, the importers’ emissions increased substantially. The emissions from the power sector in Hebei, the largest power importer of China, increased by 74 Mt. Emissions of Beijing, increased by 60 Mt (320%), in 2010. Thus, we suggest that the Chinese government should take the emissions, as calculated from the consumption perspective, into account when formulating and assessing local CO2 emission reduction targets.

  9. Optimization of Electric Power Leveling Systems by using Taper-Off-Reflectance Particle Swarm Optimization

    Makino, Yohei; Fujii, Toshinori; Imai, Jun; Funabiki, Shigeyuki

    Recently, it is desired to develop energy control technologies for environmental issues such as global warming and exhaustion of fossil fuel. Power fluctuations in large power consumers may cause the instability of electric power systems and increase the cost of the electric power facility and electricity charges. Developing the electric power-leveling systems (EPLS) to compensate the power fluctuations is necessary for future electric power systems. Now, EPLS with an SMES have been proposed as one of the countermeasures for the electric power quality improvement. The SMES is superior to other energy storage devices in response and storage efficiency. The authors proposed the EPLS based on fussy control with the SMES. For this practical implementation, optimizing control gain and SMES capacity is an important issue. This paper proposes a new optimization method of the EPLS. The proposed algorithm is novel particle swarm optimization based on taper-off reflectance (TRPSO). The proposed TRPSO optimizes the design variables of the EPLS efficiently and effectively.

  10. Quantum cascade laser in a master oscillator power amplifier configuration with Watt-level optical output power.

    Hinkov, Borislav; Beck, Mattias; Gini, Emilio; Faist, Jérôme

    2013-08-12

    We present the design and realization of short-wavelength (λ = 4.53 μm) and buried-heterostructure quantum cascade lasers in a master oscillator power amplifier configuration. Watt-level, singlemode peak optical output power is demonstrated for typical non-tapered 4 μm wide and 5.25 mm long devices. Farfield measurements prove a symmetric, single transverse-mode emission in TM(00)-mode with typical divergences of 25° and 27° in and perpendicular to growth direction, respectively. We demonstrate singlemode tuning over a range of 7.9 cm(-1) for temperatures between 263K and 313K and also singlemode emission for different driving currents. The side mode suppression ratio is measured to be higher than 20 dB. PMID:23938833

  11. A Polymer Optical Fiber Fuel Level Sensor: Application to Paramotoring and Powered Paragliding

    David Sánchez Montero; Carmen Vázquez; Pedro Contreras Lallana

    2012-01-01

    A low-cost intensity-based polymer optical fiber (POF) sensor for fuel level measurements in paramotoring and powered paragliding is presented, exploiting the advantages of the optical fiber sensing technology. Experimental results demonstrate that the best option can be performed by stripping the fiber at the desired discrete points to measure the fuel level as well as with a gauge-shape fiber bending. The prototype has a good linearity, better than 4% full scale (F.S.), and sensitivity arou...

  12. A review of studies on low-level vibrations as a source of electric power generation

    RAHMATİAN, Mohammad Ali; RAHMATİAN, Mohammad Rasoul; RAHİMZADEH, Hamed

    2015-01-01

    Abstract. Recent advances in low power VLSI design, with a low duty cycle has been able to resolve wireless sensor problems. In addition, researchers are looking to generate electrical energy from vibrations. The present paper discusses the low level vibration sources and their use in piezoelectric circuit for the production of electrical energy. The simulation results show that this scheme can convert low-level vibrations in nature, home environment, workplace, etc. into electrical energy.

  13. Design for reliability in power electronics in renewable energy systems – status and future

    Wang, Huai; Blaabjerg, Frede; Ma, Ke;

    2013-01-01

    maintenance costs, and herefore, low Levelized-Cost-of-Energy (LCOE) of renewable energy systems. This paper presents the prior-art Design for Reliability (DFR) process for power converters and addresses the paradigm shift to Physics-of-Failure (PoF) approach and mission profile based analysis. Moreover, the......Advances in power electronics enable efficient and flexible interconnection of renewable sources, loads and electric grids. While targets concerning efficiency of power converters are within reach, recent research endeavors to predict and improve their reliability to ensure high availability, low...... lifetime prediction of reliability-critical components IGBT modules is discussed in a 2.3 MW wind power converter. Finally, the challenges and opportunities to achieve more reliable power electronic converters are discussed....

  14. The natural radioactive level of the coal, coal cinder and slag from power plants

    The -ray spectrometer was used to analyze the natural radioactive level of the coal from Urumqi, Yi li and Ha mi areas; coal cinder and slag from China power plant and state power plant in Urumqi. The average value of and of coal is 5.54, 3.51, 69.15 from Urumqi; 9.59, 4.02, 72.95 from Yi li; 7.42, 4.87, 88.32 from Ha mi; the coal cinder is 29.31, 15.57, 111.39 from China power plant; 24.67, 16.22, 133.98 from state power plant, respectively. The result reveals that the coal cinder's application range has no limit according to national standard. (authors)

  15. Estimating Brand Level Demand Elasticities and Measuring Market Power for Regular Carbonated Soft Drinks

    Langan, Glenn E.; Cotterill, Ronald W.

    1994-01-01

    This paper reports econometric estimation of brand level demand (AIDS) elasticities for regular carbonated soft drinks using Information Resources, Inc. panel data. Own and cross price elasticities are used to measure actual and hypothetical market power that would arise from potential mergers or collusive pricing arrangements.

  16. Empirical LTE Smartphone Power Model with DRX Operation for System Level Simulations

    Lauridsen, Mads; Noël, Laurent; Mogensen, Preben

    An LTE smartphone power model is presented to enable academia and industry to evaluate users’ battery life on system level. The model is based on empirical measurements on a smartphone using a second generation LTE chipset, and the model includes functions of receive and transmit data rates and...

  17. Prospective Physics Teachers' Level of Understanding Energy, Power and Force Concepts

    Saglam-Arslan, Aysegul; Kurnaz, Mehmet Altan

    2009-01-01

    The aim of this study is to determine prospective physics teachers' level of understanding of the concepts of energy and the related concepts of force and power. The study was carried out with the participation of 56 physics education department students at a university in Karadeniz region. All participants had previously taken an introductory…

  18. Improvement of High-Power Three-Level Explosion-Proof Inverters Using Soft Switching Control Based on Optimized Power-Loss Algorithm

    Shi-Zhou Xu

    2015-01-01

    Full Text Available The high-power three-level explosion-proof inverters demand high thermal stability of power devices, and a set of theories and methods is needed to achieve an accurate power-loss calculation of power devices, to establish heat dissipation model, and ultimately to reduce the power loss to improve thermal stability of system. In this paper, the principle of neutral point clamped three-level (NPC3L inverter is elaborated firstly, and a fourth-order RC equivalent circuit of IGBT is derived, on which basis the power-loss model of IGBT and the optimized maternal power-loss thermal model, using an optimized power-loss algorithm, are established. Secondly, in accordance with the optimized maternal power-loss thermal model, the generic formulas of power-loss calculation are deduced to calculate the power-loss modification values of NPC3L and soft switching three-level (S3L inverters, which will be the thermal sources during thermal analysis for maternal power-loss thermal models. Finally, the experiment conducted on the 2.1 MW experimental platform shows that S3L inverter has the same excellent output characteristics with NPC3L inverter, reduces the power loss significantly by 213 W in each half-bridge, and decreases the temperature by 10°C, coinciding with the theoretical calculation, which verifies the accuracy of optimized power-loss algorithm and the effectiveness of the improvement.

  19. Review of practicing Level-2 probabilistic safety analysis for Chinese nuclear power plants

    Existing studies about Level-2 PSA (Probabilistic Safety Analysis) in the world, covering NUREG-1150, IAEA-SSG-4, 50-P-8 and Level-2 plant PSA reports for AP1000 and EPR, serve in this paper as the basis of a literature study aimed at determining guidelines to practice Level-2 PSA in Chinese commercial nuclear power plants. We recapitulate the main technical elements composing Level-2 PSA: the familiarization with plant data and systems, interface with Level-1, containment performance analysis, accident progression and containment event tree analysis, source term and release category analysis, sensitivity, importance and uncertainty analysis, and the relationship between them. At last, outcomes of Level-2 PSA are presented. (author)

  20. Study on gamma radiation levels around Thermal Power Plant and Zindal Steel Plant of Bellary district

    Indoor and outdoor ambient gamma radiation levels have been measured around Thermal Power Plant and Zindal Steel Plant of Bellary district by using Scintillometer (Type SM 141D) manufactured by Electronics Corporation of India Limited (ECIL). All measurements were made 1 m in above the ground level. The arithmetic mean of the readings was taken as representative figure for each location. The exposure rate in μR.h-1 was converted into absorbed dose rate nGyh-1 using the conversion factor of 1μR.h-1 = 8.7 nGy.h-1, which stems from the definition of the Roentgen. The average values of gamma radiation levels in outdoor and indoor atmosphere around Thermal Power Plant and Zindal Steel Plant of Bellary district have been measured using Scintillometer. We have also measured the variation of gamma radiation level in different rooms of same dwelling in different places of the study area. The data shows indoor gamma radiation is higher than outdoor gamma radiation level. The gamma exposure rate in outdoor and indoor atmosphere of the study area found to be varied from 113.1 to 234.6 nGh-1 and 139.2 to 365.2 nGh1-1 with arithmetic mean of 165.3 nGh-1 and 203.6 nGh-1, respectively. The study shows that indoor gamma radiation is higher than outdoor gamma radiation level. Dwelling having granite floorings shows maximum level of gamma radiation when compared to other floorings. Kitchen and bed rooms shows higher radiation level compared to halls. Maximum outdoor gamma radiation level have been observed near the dumps of thermal power plant

  1. Development of a Review Guide for a Level-3 PSA of Nuclear Power Plants

    A probabilistic safety assessment (PSA) provides a systematic analysis to identify and quantify all the risks that a plant imposes to the operators, general public and the environment. The main benefits of a PSA is to provide insights into the safety aspects of a plant design, performance, and the potential environmental impacts of postulated accidents, including the identification of dominant risk contributors, and a comparison of the options for reducing a risk. Among the three levels of a PSA, a Level-3 PSA provides insights into the relative importance of a accident prevention and mitigative measures expressed in terms of the adverse consequences for the health of the public, and the contamination of land, air, water, and foodstuffs. Finally, a Level-3 PSA provides insights into the relative effectiveness of emergency response planning aspects of an off-site accident management, and into the economic impacts. Regulatory bodies are generally responsible for the specification of safety criteria which can be related to PSAs at Level-1, -2, and -3. Examples of these criteria are the frequency of a severe core damage for a Level-1, and the frequency of large releases of radionuclides for a Level-2 PSA. The most commonly used Level-3 related safety criteria are early and cancer fatality risks. The regulatory body in Korea has developed the review guides for the Level-1 and -2 PSA. And the current regulatory structure for the licensing of nuclear power plants is established for an LWR-oriented structure. However, the accomplishment of a Level-3 PSA as well as Level-1 and -2 PSA is necessary in order to establish the risk-informed and performance-based regulatory structure for the licensing of future nuclear power plants. In such a situation, the need for the accomplishment of a Level-3 PSA is increasing. Therefore, the main goal of this study is to develop a review guide for the Level-3 PSA

  2. Reactor core water level monitor system and startup for CPR1000 nuclear power plant

    Reactor core water level monitor system is an important system used in CPR1000 nuclear power plant for monitoring the water level of reactor core after LOCA accident. The level measured by this system is used directly in the accident operation procedure. The principle of the measurement and the component of the system were introduced. According to the startup work of the first project for CPR1000, the goal for the first startup of this system relying on domestic engineering team was achieved. (authors)

  3. Evaluation of safety issues on newly regulated nuclear power plant by tsunami-level 1 PRA

    The tsunami caused by the Great East Japan Earthquake triggered severe accidents involving the units 1 to 4 at the Fukushima Dai-ichi nuclear power station (NPS). In order to re-operate existing nuclear power plants it should be necessary to reduce the core damage frequency on risk by tsunami. In this work, effects of the off-site power supply installation on resuming operation of nuclear power plants were investigated by utilizing the Tsunami-Level 1 Probability Risk Assessment (PRA). Unit 2 of the Onagawa nuclear power station, which resembled units 2 and 3 of Fukushima Dai-ichi, was selected for PRA. First, event-tree was created for the units of the Onagawa nuclear power station with the safety systems such as Emergency Core Cooling System (ECCS), investigating the plant situation at the time of the earthquake and tsunami occurrences. It was assumed that the magnitude of the tsunami was equivalent to the Great East Japan Earthquake. The accident-analytical progression-time was 36 hours, determined from the core-damage occurrence of the unit 3 of Fukushima Dai-ichi nuclear power station. Failure probabilities were calculated by the fault tree, which was created from the elements listed in the event tree. For the calculation, failure rates reported by the NUCIA (NUClear Information Archives) were primarily utilized. Then, obtained failure probabilities were embedded to the event tree. Core damage probabilities were evaluated by calculating success and failure rates for each accidental progression and scenarios. Restoration of the failed equipment and machineries was not considered in the analysis. Installation of the power supply vehicles at the nuclear power plant site reduced the core damage probability from 2.58×10-6 to 8.56×10-7. However, continued addition of the power supply vehicles could not lower the core damage probability further more. In the case of Unit 2 of Onagawa nuclear power station, there could be a limit to lower the core damage probability

  4. Survey of ambient electromagnetic and radio-frequency interference levels in nuclear power plants

    This document reports the results of a survey of ambient electromagnetic conditions in representative nuclear power plants. The U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research engaged the Oak Ridge National Laboratory (ORNL) to perform these measurements to characterize the electromagnetic interference (EMI) and radio-frequency interference (RFI) levels that can be expected in nuclear power plant environments. This survey is the first of its kind, being based on long-term unattended observations. The data presented in this report were measured at eight different nuclear units and required 14 months to collect. A representative sampling of power plant conditions (reactor type, operating mode, site location) monitored over extended observation periods (up to 5 weeks) were selected to more completely determine the characteristic electromagnetic environment for nuclear power plants. Radiated electric fields were measured over the frequency range of 5 MHz to 8 GHz. Radiated magnetic fields and conducted EMI events were measured over the frequency range of 305 Hz to 5 MHz. Highest strength observations of the electromagnetic ambient environment across all measurement conditions at each site provide frequency-dependent profiles for EMI/RFI levels in nuclear power plants

  5. Application of Back Propagation Neural Network to Drum Level Control in Thermal Power Plants

    Preeti Manke

    2012-03-01

    Full Text Available The paper describes the development and testing of a neural network based drum level controller for sub-critical thermal power plant boilers. Experimental data obtained from an operational coal fired power plant (500MW Thermal Power Station, Korba, India is used to train the neural network. This model proposes a simple training algorithm for a class of nonlinear systems, which enables the neural network to be trained with the output errors of the controlled plant. The only a priori knowledge of the controlled plant is the direction of its output response. Due to its simple structure and algorithm, and good performance, the proposed controller has high potential for handling difficult problems in process-control systems. The Artificial neural networks (ANN modeling can significantly reduce the frequency of deviations and the degree of deviation of the water level in the drum. The ANN model to be applied for the boiler feed system in the power plant will not only increase the efficiency of the system but also shall considerably reduce the tripping of the power plant.

  6. Computer-based control of nuclear power information systems at international level

    In most highly industrialized countries of the world information plays major role in anti-nuclear campaign. Information and discussions on nuclear power need critical and objective analysis before the structured information presentation to the public to avoid bias anti-nuclear information on one side and neglect of great risk in nuclear power. This research is developing a computer-based information system for the control of nuclear power at international level. The system is to provide easy and fast information highways for the followings: (1) Low Regulatory dose and activity limit as level of high danger for individuals and public. (2) Provision of relevant technical or scientific education among the information carriers in the nuclear power countries. The research is on fact oriented investigation about radioactivity. It also deals with fact oriented education about nuclear accidents and safety. A standard procedure for dissemination of latest findings using technical and scientific experts in nuclear technology is developed. The information highway clearly analyzes the factual information about radiation risk and nuclear energy. Radiation cannot be removed from our environment. The necessity of radiation utilizations defines nuclear energy as two-edge sword. It is therefore, possible to use computer-based information system in projecting and dissemination of expert knowledge about nuclear technology positively and also to use it in directing the public on the safety and control of the nuclear energy. The computer-based information highway for nuclear energy technology is to assist in scientific research and technological development at international level. (author)

  7. Improvement of High-Power Three-Level Explosion-Proof Inverters Using Soft Switching Control Based on Optimized Power-Loss Algorithm

    Shi-Zhou Xu; Feng-You He

    2015-01-01

    The high-power three-level explosion-proof inverters demand high thermal stability of power devices, and a set of theories and methods is needed to achieve an accurate power-loss calculation of power devices, to establish heat dissipation model, and ultimately to reduce the power loss to improve thermal stability of system. In this paper, the principle of neutral point clamped three-level (NPC3L) inverter is elaborated firstly, and a fourth-order RC equivalent circuit of IGBT is derived, on w...

  8. A new tool to estimate maximum wind power penetration level: In perspective of frequency response adequacy

    Highlights: • This study proposes a new tool to estimate maximum wind power penetration level. • This tool takes frequency response adequacy into account. • System frequency sensitivity is modelled as a function of inertia and headroom. • A practical power system is investigated as a case study. • Outputs from the proposed tool match with dynamic simulation results. - Abstract: Wind energy is becoming a significant source of generation in many countries because of its zero fuel cost and no air pollution. Due to integration of large-scale wind power in conventional grids, synchronous generators are being economically replaced. Modern wind farms are based on power electronics interface; and unlike synchronous generators, they do not have inherent frequency support capability. So, in a combined synchronous and non-synchronous machine based power system, it has always been a concern for a network operator to maintain system frequency within acceptable limits following a major disturbance. From power system security point of view, wind penetration can be limited by frequency response criteria. Up to now, several methodologies have been proposed to estimate maximum threshold of wind integration. However, none of them recommends how a system operator could be immediately informed about a secured wind penetration limit, as soon as generation profile is known. This paper proposes a new estimation tool of maximum wind penetration level from the frequency response adequacy point of view. Available system information viz. inertia and headroom are used as input parameters in the developed tool. Output of this tool will provide the highest margin of wind power that can be integrated at a particular load condition without violating frequency response constraints. The proposed technique is applied and analysed for a 250 bus, 65 machine Australian electricity network

  9. Multi-spacecraft measurement of anisotropic power levels and scaling in solar wind turbulence

    K. T. Osman

    2009-08-01

    Full Text Available Measurements by the four Cluster spacecraft in the solar wind are used to determine quantitatively the field-aligned anisotropy of magnetohydrodynamic inertial range turbulence power levels and spectral indexes. We find, using time-lagged second order structure functions, that the spectral index is near 2 around the field-parallel direction, which is consistent with a "critical balance" turbulent cascade. Solar wind fluctuations are found to be anisotropic with power mainly in wavevectors perpendicular to the mean field, where the spectral index is around 5/3.

  10. Airborne monitoring of radioactivity level in the regions surrounding Qinshan Nuclear Power Plant and Shanghai city

    The author introduces the monitoring method and main results of environmental γ radioactivity level and surface density of 137Cs and 60Co on the ground in the regions surrounding Qinshan Nuclear Power Plant and Shanghai City, using airborne γspectrometer. The results show that the absorbed dose rate in air (1 m above ground) is lower normal background, the average is 52.7 nGy/h in the regions. No pollution from Nuclear Power Plant had been monitored, but two artificial pollution points at the fertilizer factory of Fengxian County and the refractory material factory of Haiyan County had unexpectly been monitored

  11. Photovoltaic Shading Testbed for Module-Level Power Electronics: 2014 Update

    Deline, C.; Meydbray, J.; Donovan, M.

    2014-08-01

    The 2012 NREL report 'Photovoltaic Shading Testbed for Module-Level Power Electronics' provides a standard methodology for estimating the performance benefit of distributed power electronics under partial shading conditions. Since the release of the report, experiments have been conducted for a number of products and for different system configurations. Drawing from these experiences, updates to the test and analysis methods are recommended. Proposed changes in data processing have the benefit of reducing the sensitivity to measurement errors and weather variability, as well as bringing the updated performance score in line with measured and simulated values of the shade recovery benefit of distributed PV power electronics. Also, due to the emergence of new technologies including sub-module embedded power electronics, the shading method has been extended to include power electronics that operate at a finer granularity than the module level. An update to the method is proposed to account for these emerging technologies that respond to shading differently than module-level devices. The partial shading test remains a repeatable test procedure that attempts to simulate shading situations as would be experienced by typical residential or commercial rooftop photovoltaic (PV) systems. Performance data for multiple products tested using this method are discussed, based on equipment from Enphase, Solar Edge, Maxim Integrated and SMA. In general, the annual recovery of shading losses from the module-level electronics evaluated is 25-35%, with the major difference between different trials being related to the number of parallel strings in the test installation rather than differences between the equipment tested.

  12. Disentangling Bargaining Power from Individual and Household Level to Institutions: Evidence on Women’s Position in Ethiopia

    Staveren, Irene; Mabsout, Ramzi

    2010-01-01

    textabstractSUMMARY Women's bargaining power is generally analyzed only with individual level and household level variables. We add a third level, namely institutional bargaining power. We define this as bargaining power which one party freely derives from unequal social norms. In the bargaining literature there is a common paradoxical finding, namely that more access to and control over individual resources sometimes decreases rather than increases women‟s bargaining outcomes. With household...

  13. Explosive power of lower limbs in rhythmic gymnastics athletes in different competitive levels

    Amanda Batista SANTOS

    2016-03-01

    Full Text Available Abstract The explosive power in Rhythmic Gymnastics shows itself in the great majority of movements and elements performed by the gymnasts, particularly in the jumps, which are essential corporal movements in this sport. The training directed to the development of jumping capacity presents a large quantity of exercises which aim to improve muscular power in the lower limbs and therefore the impulsion capacity. The vertical impulsion is an important measure used to calculate the explosive power of the lower limbs and is directly connected to the success that the gymnast will be able to achieve. Therefore, the aim of this study is to evaluate the height of two jumps in the RG (stag jump and Cossack jump in contact mat Ergojump, which calculates the jump height in connection with the flight timing, executed by national level junior gymnasts and to compare them to the results of the Junior National Team - in total 30 junior gymnasts with 13.73 ± 0.17 years old. Furthermore, to compare the levels of explosive power of preferred lower limb (PLL and non-preferred lower limb (NPLL of all gymnasts in the study, in order to verify eventual functional asymmetries. For the statistical analysis we used Parametric Tests (t Test and Nonparametric (Mann-Whitney Test and Wilcoxon Test. The gymnasts of the National Team achieved superior marks in 33.3% of the tests and 83.3% of the gymnasts of our sample did not present explosive power asymmetries. We conclude that the gymnasts of the National Team did not show the expected superiority in the tests, and the most of gymnasts presented a harmonious development of explosive power for both lower limbs, since they did not show functional asymmetries.

  14. Power optimization of digital baseband WCDMA receiver components on algorithmic and architectural level

    M. Schämann

    2008-05-01

    Full Text Available High data rates combined with high mobility represent a challenge for the design of cellular devices. Advanced algorithms are required which result in higher complexity, more chip area and increased power consumption. However, this contrasts to the limited power supply of mobile devices.

    This presentation discusses the application of an HSDPA receiver which has been optimized regarding power consumption with the focus on the algorithmic and architectural level. On algorithmic level the Rake combiner, Prefilter-Rake equalizer and MMSE equalizer are compared regarding their BER performance. Both equalizer approaches provide a significant increase of performance for high data rates compared to the Rake combiner which is commonly used for lower data rates. For both equalizer approaches several adaptive algorithms are available which differ in complexity and convergence properties. To identify the algorithm which achieves the required performance with the lowest power consumption the algorithms have been investigated using SystemC models regarding their performance and arithmetic complexity. Additionally, for the Prefilter Rake equalizer the power estimations of a modified Griffith (LMS and a Levinson (RLS algorithm have been compared with the tool ORINOCO supplied by ChipVision. The accuracy of this tool has been verified with a scalable architecture of the UMTS channel estimation described both in SystemC and VHDL targeting a 130 nm CMOS standard cell library.

    An architecture combining all three approaches combined with an adaptive control unit is presented. The control unit monitors the current condition of the propagation channel and adjusts parameters for the receiver like filter size and oversampling ratio to minimize the power consumption while maintaining the required performance. The optimization strategies result in a reduction of the number of arithmetic operations up to 70% for single components which leads to an

  15. Application of PSA to Assess the Safety Level of Nuclear Power Plants

    This paper reviews the application of PSA in German nuclear power plant regulation. From a fundamental point of view, it has to be mentioned that as stipulated in the corresponding requirements, regulatory decision making in Germany is primarily based on deterministic analyses and evaluations. Therefore, PSA is not used as a stand alone but as a supplementary basis. In this context PSA has developed a valuable tool with continuously growing importance. Level 1+ PSAs are now elaborated for all German nuclear power plants in operation, most of them are already reviewed by the competent supervisory authority and its experts. Current research activities on the federal level primarily concentrate on the further development of the methodology in the areas human factor, common cause failures, accident management measures and reduction of uncertainties in methods and data. (author)

  16. Availability analysis of nuclear power system with performance degradation and multi-level support capacity

    The availability analysis which combines universal generating function (UGF) with Markov state transition theory was proposed to nuclear power system with performance degradation and multi-level support capacity. The system logical model and performance state combination model were constructed by UGF. Furthermore, the computational expression for component state probability based on Markov method was constructed considering performance degradation and multi-level support capacity. And then the model was embedded into the logic model and performance state combination model by UGF. This combined model was used in availability analysis of an actual example with different performance demands, and the influence of maintenance condition to system availability was also analyzed. The results show that this method captures the operational and maintenance characteristics. The obtained results can provide guidance to nuclear power system operation, management, maintenance decision-making and support condition analysis. (authors)

  17. Habit, custom, and power: a multi-level theory of population health.

    Zimmerman, Frederick J

    2013-03-01

    In multi-level theory, individual behavior flows from cognitive habits, either directly through social referencing, rules of thumb, or automatic behaviors; or indirectly through the shaping of rationality itself by framing or heuristics. Although behavior does not arise from individually rational optimization, it generally appears to be rational, because the cognitive habits that guide behavior evolve toward optimality. However, power imbalances shaped by particular social, political, and economic structures can distort this evolution, leading to individual behavior that fails to maximize individual or social well-being. Replacing the dominant rational-choice paradigm with a multi-level theoretical paradigm involving habit, custom, and power will enable public health to engage in rigorous new areas of research. PMID:23415591

  18. Processing of low-level and intermediate-level radioactive wastes from the nuclear power plant Muehleberg at Mol

    Between October 1986 and April 1987 two contracts were concluded between the nuclear power plant Muehleberg and the German firm Transnuklear GmbH for the processing of low-level and intermediate-level radioactive wastes from Muehleberg in the incineration facility at Mol in Belgium. In the contracts, transport of the wastes to Mol and back was included. According to the contracts the maximum admissible surface dose rate of the containers enclosing the wastes was 3000 mR/h. The actual maximum value of the surface dose rate was 1800 mR/h. On January 8, 1988, Swiss press published a statement to the effect that those wastes having a surface dose rate of more than 200 mR/h cannot be processed at Mol and must be transported back to Switzerland. Three representatives of Muehleberg visited Mol to discuss the conflicting information. The result of their inquiries was that the processing and transport of foreign wastes at Mol are currently suspended due to the irregularities associated with Transnuklear. Neither the safety nor the operation of the Muehleberg facility are jeopardized through the incident

  19. Computational and experimental research of internal combustion engine with spark ignition and quality power level control

    О. П. Домбровский; Р. Ф. Зиннатуллин; Е. Г. Стругова

    2013-01-01

    The article presents the methodology of injection and combustion processes simulation in the internal combustion engine with unified working process. The results of computational study of injection and combustion processes in the combustion chamber of experimental two-stroke engine are presented. The possibility of full-range quality power level control and full fuel-burning is experimentally and computationally shown on two-stroke gasoline engine, the results of study are presented. Reducing...

  20. POPCYCLE: a computer code for calculating nuclear and fossil plant levelized life-cycle power costs

    POPCYCLE, a computer code designed to calculate levelized life-cycle power costs for nuclear and fossil electrical generating plants is described. Included are (1) derivations of the equations and a discussion of the methodology used by POPCYCLE, (2) a description of the input required by the code, (3) a listing of the input for a sample case, and (4) the output for a sample case

  1. A Transformer-less Partial Power Boost Converter for PV Applications Using a Three-Level Switching Cell

    Agamy, Mohammed; Harfman-Todorovic, Maja; Elasser, Ahmed; Essakiappan, Somasundaram

    2013-03-01

    Photovoltaic architectures with distributed power electronics provide many advantages in terms of energy yield as well as system level optimization. As the power level of the solar farm increases it becomes more beneficial to increase the dc collection network voltage, which requires the use of power devices with higher voltage ratings, and thus making the design of efficient, low cost, distributed power converters more challenging. In this paper a simple partial power converter topology is proposed. The topology is implemented using a three-level switching cell, which allows the use of semiconductor devices with lower voltage rating; thus improving design and performance and reducing converter cost. This makes the converters suitable for use for medium to high power applications where dc-link voltages of 600V~1kV may be needed without the need for high voltage devices. Converter operation and experimental results are presented for two partial power circuit variants using three-level switching cells.

  2. A Polymer Optical Fiber Fuel Level Sensor: Application to Paramotoring and Powered Paragliding

    David Sánchez Montero

    2012-05-01

    Full Text Available A low-cost intensity-based polymer optical fiber (POF sensor for fuel level measurements in paramotoring and powered paragliding is presented, exploiting the advantages of the optical fiber sensing technology. Experimental results demonstrate that the best option can be performed by stripping the fiber at the desired discrete points to measure the fuel level as well as with a gauge-shape fiber bending. The prototype has a good linearity, better than 4% full scale (F.S., and sensitivity around 0.5 V per bend are obtained. Hysteresis due to residual fluid at the sensing points is found to be less than 9% F.S.

  3. Biographical learning in top-level coaching - personal styles and the power of practical sense

    Christensen, Mette Krogh

    : Biographical learning in top-level coaching - personal styles and the power of practical sense. There is a growing body of studies in sports coaching cultures, comprising research focusing on the individual learning processes and life histories of top-level coaches. Even if top-level sport has become...... increasingly professionalized, the role of the top-level coach and the developmental pathways of the coaches differ widely in both areas of experience and amount of experience. In this paper I draw on theories on biographical learning, idiosyncratic learning and development of coaching expertise. This paper...... aspects of coaching expertise: 1) the coaches’ descriptions of their development of expertise as a “personal journey” and a matter of unique pathways, and 2) the coaches’ use of social constructed practical sense in their daily work, particularly in identification and assessment of skillfulness and talent...

  4. Modelling and measurement of the absolute level of power radiated by antenna integrated THz UTC photodiodes.

    Natrella, Michele; Liu, Chin-Pang; Graham, Chris; van Dijk, Frederic; Liu, Huiyun; Renaud, Cyril C; Seeds, Alwyn J

    2016-05-30

    We determine the output impedance of uni-travelling carrier (UTC) photodiodes at frequencies up to 400 GHz by performing, for the first time, 3D full-wave modelling of detailed UTC photodiode structures. In addition, we demonstrate the importance of the UTC impedance evaluation, by using it in the prediction of the absolute power radiated by an antenna integrated UTC, over a broad frequency range and confirming the predictions by experimental measurements up to 185 GHz. This is done by means of 3D full-wave modelling and is only possible since the source (UTC) to antenna impedance match is properly taken into account. We also show that, when the UTC-to-antenna coupling efficiency is modelled using the classical junction-capacitance/series-resistance concept, calculated and measured levels of absolute radiated power are in substantial disagreement, and the maximum radiated power is overestimated by a factor of almost 7 dB. The ability to calculate the absolute emitted power correctly enables the radiated power to be maximised through optimisation of the UTC-to-antenna impedance match. PMID:27410104

  5. Quantitative Model and Metrics of Electrical Grids’ Resilience Evaluated at a Power Distribution Level

    Alexis Kwasinski

    2016-02-01

    Full Text Available This paper presents a framework to systematically measure and assess power grids’ resilience with a focus on performance as perceived by customers at the power distribution level. The proposed framework considers an analogous measure of availability as a basic metric for resilience and defines other key resilience-related concepts and metrics, such as resistance and brittleness. This framework also provides a measurement for the degree of functional dependency of loads on power grids and demonstrates how the concepts of resilience and dependency are inherently related. It also discusses the implications of considering human-centered processes as fundamental constituting components of infrastructure systems. Thanks to its quantitative nature, the proposed resilience framework enables the creation of tools to evaluate power grids’ performance as a lifeline and to assess the effects of plans for optimal electrical power infrastructure deployment and operation. The discussion is supported by practical examples and empirical records from field damage assessments conducted after recent notable natural disasters.

  6. Nonlinear Adaptive Dynamic Output-Feedback Power-Level Control of Nuclear Heating Reactors

    Zhe Dong

    2013-01-01

    Full Text Available Due to the high safety performance of small nuclear reactors, there is a promising future for small reactors. Nuclear heating reactor (NHR is a small reactor that has many advanced safety features such as the integrated arrangement, natural circulation at any power levels, self-pressurization, hydraulic control rod driving, and passive residual heating removing and can be applied to the fields of district heating, seawater desalination, and electricity production. Since the NHR dynamics has strong nonlinearity and uncertainty, it is meaningful to develop the nonlinear adaptive power-level control technique. From the idea of physically based control design method, a novel nonlinear adaptive power-level control is given for the NHR in this paper. It is theoretically proved that this newly built controller does not only provide globally asymptotic closed-loop stability but is also adaptive to the system uncertainty. Numerical simulation results show the feasibility of this controller and the relationship between the performance and controller parameters.

  7. Minimizing the Levelized Cost of Energy in Single-Phase Photovoltaic Systems with an Absolute Active Power Control

    Yang, Yongheng; Koutroulis, Eftichios; Sangwongwanich, Ariya;

    2016-01-01

    Countries with considerable PhotoVoltaic (PV) installations are facing a challenge of overloading their power grid during peak-power production hours if the power infrastructure remains the same. To address this, regulations have been imposed on PV systems, where more active power control should...... be flexibly performed. As an advanced control strategy, the Absolute Active Power Control (AAPC) can effectively solve the overloading issues by limiting the maximum possible PV power to a certain level (i.e., the power limitation), and also benefit the inverter reliability due to the reduction in the thermal...... loading of the power devices. However, its feasibility is challenged by the associated energy losses. An increase of the inverter lifetime and a reduction of the energy yield can alter the cost of energy, demanding an optimization of the power limitation. Therefore, aiming at minimizing the Levelized Cost...

  8. A new high-voltage level-shifting circuit for half-bridge power ICs

    In order to reduce the chip area and improve the reliability of HVICs, a new high-voltage level-shifting circuit with an integrated low-voltage power supply, two PMOS active resistors and a current mirror is proposed. The integrated low-voltage power supply not only provides energy for the level-shifting circuit and the logic circuit, but also provides voltage signals for the gates and sources of the PMOS active resistors to ensure that they are normally-on. The normally-on PMOS transistors do not, therefore, need to be fabricated in the depletion process. The current mirror ensures that the level-shifting circuit has a constant current, which can reduce the process error of the high-voltage devices of the circuit. Moreover, an improved RS trigger is also proposed to improve the reliability of the circuit. The proposed level-shifting circuit is analyzed and confirmed by simulation with MEDICI, and the simulation results show that the function is achieved well. (semiconductor integrated circuits)

  9. Fault detection and diagnosis of the deaerator level control system in nuclear power plants

    Kim, Kyung Youn; Lee, Yoon Joon [Cheju National Univ., Cheju (Korea, Republic of)

    2004-02-01

    The deaerator of a power plant is one of feedwater heaters in the secondary system, and it is located above the feedwater pumps. The feedwater pumps take the water from the deaerator storage tank, and the Net Positive Suction Head(NPSH) should always be ensured. To secure the sufficient NPSH, the deaerator tank is equipped with the level control system of which level sensors are critical items. And it is necessary to ascertain the sensor state on-line. For this, a model-based Fault Detection and Diagnosis(FDD) is introduced in this study. The dynamic control model is formulated from the relation of input-output flow rates and liquid-level of the deaerator storage tank. Then an adaptive state estimator is designed for the fault detection and diagnosis of sensors. The performance and effectiveness of the proposed FDD scheme are evaluated by applying the operation data of Yonggwang Units 3 and 4.

  10. Global Sea Level Stabilization-Sand Dune Fixation: A Solar-powered Sahara Seawater Textile Pipeline

    Badescu, Viorel; Bolonkin, Alexander A

    2007-01-01

    Could anthropogenic saturation with pumped seawater of the porous ground of active sand dune fields in major deserts (e.g., the westernmost Sahara) cause a beneficial reduction of global sea level? Seawater extraction from the ocean, and its deposition on deserted sand dune fields in Mauritania and elsewhere via a Solar-powered Seawater Textile Pipeline (SSTP) can thwart the postulated future global sea level. Thus, Macro-engineering offers an additional cure for anticipated coastal change, driven by global sea level rise, that could supplement, or substitute for (1) stabilizing the shoreline with costly defensive public works (armoring macroprojects) and (2) permanent retreat from the existing shoreline (real and capital property abandonment). We propose Macro-engineering use tactical technologies that sculpt and vegetate barren near-coast sand dune fields with seawater, seawater that would otherwise, as commonly postulated, enlarge Earth seascape area! Our Macro-engineering speculation blends eremology with...

  11. Reactivity response analyses for the design of automatic power level control system of upgraded JRR-3

    This reports the analytical results of transient responses to inserted reactivities for the design of the automatic power level control system of upgraded JRR-3. The parameters of reactor kinetics, prompt neutron lifetime and effective delayed neutron fraction, have been calculated by neutron diffusion theory and perturbation theory using the SRAC code system. Burn-up processes, reactor temperatures and configurations of control rods have been taken into account in the calculation. The transient responses of the automatic control system to a step reactivity change of +- 7.3 * 10-4 Δk/k and a ramp reactivity change of +- 3.0 * 10-4 Δk/k/sec have been obtained by analogue computer. As the result, when a regulator rod is used for the automatic power control, its driving velocity has been designed to be 30 cm/min. It has been confirmed that this designed control system can quickly respond to the reactivity perturbations and maintain a desired power level. (author)

  12. Consideration of safety level when a country selects nuclear power plant technology

    Tu, Nguyen Hoang [KAIST, Daejeon (Korea, Republic of); Choi, Young Sung [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2012-10-15

    Energy is essential for national development. Nearly every aspect of development requires reliable access to modern energy resources. States may have different reasons for considering starting a nuclear power project to achieve their national energy needs, such as lack of available indigenous energy resources, the desire to reduce dependence upon imported energy, the need to increase the diversity of energy resources and/or mitigation of carbon emission increases. The start of a nuclear power plant project involves several complex and interrelated activities with long duration, typically lasting about 10 to 15 years. The main focus, however, is to ensure that the project is implemented successfully from the views of commercial benefits and, more importantly to ensure the acceptability of the public over long term period, safety level achieved or to be achieved by the project. This paper is aimed at providing consideration on the practical selection of a first nuclear power project in a country to ensure that the project will have enough safety level.

  13. Alternative LEU designs for the FRM-II with power levels of 20-22 MW

    Alternative LEU Designs for the FRM-II have been developed by the RERTR Program at Argonne National Laboratory (ANL) at the request of an FRM-II Expert Commission established by the German Federal Government in January 1999 to evaluate the options for using LEU fuel instead of HEU fuel in cores with power levels of 20 MW. The ANL designs would use the same building structure and maintain as many of the HEU design features as practical. The range of potential LEU fuels was expanded from previous studies to include already-tested silicide fuels with uranium densities up to 6.7 g/cm3 and the new U-Mo fuels that show excellent prospects for achieving uranium densities in the 8-9 g/cm3 range. For each of the LEU cores, the design parameters were chosen to match the 50 day cycle length of the HEU core and to maximize the thermal neutron flux in the Cold Neutron Source and beam tubes. The studies concluded that an LEU core with a diameter of about 29 cm instead of 24 cm in HEU design and operating at a power level of 20 MW would have thermal neutron fluxes that are 0.85-0.86 times that of the HEU design in the Cold Neutron Source. With a potential future upgrade to a power of 22 MW, this ratio would increase to 0.92-0.93. (author)

  14. Alterative LEU designs for the FRM-II with power levels of 20-22 MW

    Alternative LEU Designs for the FRM-II have been developed by the RERTR Program at Argonne National Laboratory (ANL) at the request of an FRM-II Expert Group established by the German Federal Government in January 1999 to evaluate the options for using LEU fuel instead of HEU fuel in cores with power levels of 20 MW. The ANL designs would use the same building structure and maintain as many of the HEU design features as practical. The range of potential LEU fuels was expanded from previous studies to include already-tested silicide fuels with uranium densities up to 6.7 g/cm3 and the new U-Mo fuels that show excellent prospects for achieving uranium densities in the 8-9 g/cm3 range. For each of the LEU cores; the design parameters were chosen to match the 50 day cycle length of the HEU core and to maximize the thermal neutron flux in the Cold Neutron Source and beam tubes. The studies concluded that an LEU core with a diameter of about 29 cm instead of 24 cm in HEU design and operating at a power level of 20 MW would have thermal neutron fluxes that are 0.85 times that of the HEU design at the center of the Cold Neutron Source. With a potential future upgrade to a power of 22 MW, this ratio would increase to 0.93

  15. A detector for monitoring the onset of cavitation during therapy-level measurements of ultrasonic power

    Hodnett, M.; Zeqiri, B.

    2004-01-01

    Acoustic cavitation occurring in the water path between a transducer and the target of a radiation force balance can provide a significant source of error during measurements of ultrasonic power. These problems can be particularly acute at physiotherapy levels (>1 W), and low frequencies (leq 1 MHz). The cavitating bubbles can absorb and scatter incident ultrasound, leading to an underestimate in the measured power. For these reasons, International Specification standards demand the use of degassed water. This imposes requirements that may actually be difficult to meet, for example, in the case of hospitals. Also, initially degassed water will rapidly re-gas, increasing the likelihood of cavitation occurring. For these reasons, NPL has developed a device that monitors acoustic emissions generated by bubble activity, for detecting the onset of cavitation during power measurements. A commercially available needle hydrophone is used to detect these emissions. The acoustic signals are then monitored using a Cavitation Detector (CD) unit, comprising an analogue electrical filter that may be tuned to detect frequency components generated by cavitating bubbles, and which provides an indication of when the measured level exceeds a pre-defined threshold. This paper describes studies to establish a suitable detection scheme, the principles of operation of the CD unit, and the performance tests carried out with a range of propagation media.

  16. A detector for monitoring the onset of cavitation during therapy-level measurements of ultrasonic power

    Hodnett, M; Zeqiri, B [National Physical Laboratory, Queens Road, Teddington, Middlesex, TW11 0LW (United Kingdom)

    2004-01-01

    Acoustic cavitation occurring in the water path between a transducer and the target of a radiation force balance can provide a significant source of error during measurements of ultrasonic power. These problems can be particularly acute at physiotherapy levels (>1 W), and low frequencies ({<=} 1 MHz). The cavitating bubbles can absorb and scatter incident ultrasound, leading to an underestimate in the measured power. For these reasons, International Specification standards demand the use of degassed water. This imposes requirements that may actually be difficult to meet, for example, in the case of hospitals. Also, initially degassed water will rapidly re-gas, increasing the likelihood of cavitation occurring. For these reasons, NPL has developed a device that monitors acoustic emissions generated by bubble activity, for detecting the onset of cavitation during power measurements. A commercially available needle hydrophone is used to detect these emissions. The acoustic signals are then monitored using a Cavitation Detector (CD) unit, comprising an analogue electrical filter that may be tuned to detect frequency components generated by cavitating bubbles, and which provides an indication of when the measured level exceeds a pre-defined threshold. This paper describes studies to establish a suitable detection scheme, the principles of operation of the CD unit, and the performance tests carried out with a range of propagation media.

  17. Alterative LEU designs for the FRM-II with power levels of 20-22 MW.

    Hanan, N. A.; Smith, R. S.; Matos, J. E.

    1999-09-27

    Alternative LEU Designs for the FRM-II have been developed by the RERTR Program at Argonne National Laboratory (ANL) at the request of an FRM-II Expert Group established by the German Federal Government in January 1999 to evaluate the options for using LEU fuel instead of HEU fuel in cores with power levels of 20 MW. The ANL designs would use the same building structure and maintain as many of the HEU design features as practical. The range of potential LEU fuels was expanded from previous studies to include already-tested silicide fuels with uranium densities up to 6.7 g/cm{sup 3} and the new U-Mo fuels that show excellent prospects for achieving uranium densities in the 8-9 g/cm{sup 3} range. For each of the LEU cores; the design parameters were chosen to match the 50 day cycle length of the HEU core and to maximize the thermal neutron flux in the Cold Neutron Source and beam tubes. The studies concluded that an LEU core with a diameter of about 29 cm instead of 24 cm in HEU design and operating at a power level of 20 MW would have thermal neutron fluxes that are 0.85 times that of the HEU design at the center of the Cold Neutron Source. With a potential future upgrade to a power of 22 MW, this ratio would increase to 0.93.

  18. Assessment of two-level heat pump installations’ power efficiency for heat supply systems

    Аlla Е. Denysova

    2015-06-01

    Full Text Available The problem of energy saving becomes one of the most important in power engineering. It is caused by exhaustion of world reserves in hydrocarbon fuel, such as gas, oil and coal representing sources of traditional heat supply. Conventional sources has essential shortcomings: low power, ecological and economic efficiencies, that can be eliminated by using alternative methods of power supply, like the considered one: low-temperature natural heat of ground waters of on the basis of heat pump installations application. The heat supply system considered provides an effective use of two-level heat pump installation operating as heat source the Odessa city ground waters during the lowest ambient temperature period. Proposed is a calculation method of heat pump installations on the basis of geothermal heat supply. Calculated are the values of electric energy consumption N by the compressors’ drive, and the heat supply system transformation coefficient µ for a source of geothermal heat from ground waters of Odessa city allowing to estimate efficiency of two-level heat pump installations.

  19. Power Quality Improvement at Distribution Level for Grid Connected Renewable Energy Sources

    S. Syed Ahmed

    2014-09-01

    Full Text Available The non-linear load current harmonics may result in voltage harmonics and can create a serious PQ problem in the power system network. Active power filters (APF are extensively used to compensate the load current harmonics and load unbalance at distribution level. This results in an additional hardware cost. However, in this project it has incorporated the features of APF in the conventional inverter interfacing renewable with the grid, without any additional hardware cost. Here, the main idea is the maximum utilization of inverter rating which is most of the time underutilized due to intermittent nature of RES. The grid-interfacing inverter can effectively be utilized to perform the four important functions they are to transfer active power harvested from the renewable resources (wind, solar, etc., load reactive power demand support, current harmonics compensation at PCC and current unbalance and neutral current compensation in case of 3-phase 4-wire system. Moreover, with adequate control of grid-interfacing inverter, all the four objectives can be accomplished either individually or simultaneously. The PQ constraints at the PCC can therefore be strictly maintained within the utility standards without additional hardware cost. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies

  20. Power infrastructure quality and manufacturing productivity in Africa: A firm level analysis

    This study sought to examine the impact of the quality of power infrastructure on productivity in African manufacturing firms using data from the World Bank enterprise surveys. We measured power infrastructure quality using the number of hours per day without electricity and the percentage of output lost due to outages and found these indicators to be negative and significant determinants of productivity. These variables seem to be significant determinants in Uganda, Tanzania and Zambia as well as in the food and agriculture sector. To improve economic growth and encourage employment creation, governments in Africa have to come up with measures to improve the reliability of electricity infrastructure. - Highlights: • Power infrastructure quality indicators are found to have a negative and significant effect. • The power quality indicators have varied effects both at country and sector level. • Owning a generator minimises the negative impact of outages in Uganda, Tanzania and Mauritius. • Other controls like labour, capital, foreign ownership etc. have a positive and significant effect. • The firm age variable is insignificant suggesting that accumulated knowledge does not matter

  1. Minimizing the Levelized Cost of Energy in Single-Phase Photovoltaic Systems with an Absolute Active Power Control

    Yang, Yongheng; Koutroulis, Eftichios; Sangwongwanich, Ariya;

    2015-01-01

    Several countries with considerable PhotoVoltaic (PV) installations are facing a challenge of overloading the power infrastructure during peak-power production hours. Regulations have been imposed on the PV systems, where more active power control should be flexibly performed. As an advanced...... control strategy, the Absolute Active Power Control (AAPC) can effectively solve the overloading issues by limiting the maximum possible PV power to a certain level (i.e., the power limitation), and also benefit the inverter reliability. However, its feasibility is challenged by the energy loss....... An increase of the inverter lifetime and a reduction of the energy yield can alter the cost of energy, demanding an optimization of the power limitation. Therefore, aiming at minimizing the Levelized Cost of Energy (LCOE), the power limit is optimized for the AAPC strategy in this paper. The optimization...

  2. Discussions on results of environmental background radiation level investigation for Tianwan Nuclear Power Plant

    The environmental background radiation level investigation surrounding Tianwan Nuclear Power Plant was conducted for 2 years by China Institute for Radiation Protection. The investigation results are all collected in this paper and discussions are made on some results, such as 90Sr and 3H contents in water bodies, 137Cs and 7Be contents in plant, 137Cs and 40K contents in animal and animal products, 137Cs contents in soil, plant and animal, as well as considerations in choosing indicating organism, etc. Main conclusions are presented as well. (author)

  3. Modeling of Busbars in High Power Neutral Point Clamped Three-Level Inverters

    YI Rung; ZHAO Zhengming; ZHONG Yulin

    2008-01-01

    The busbars in high power neutral point clamped three-level inverters are modeled using the Maxwell Q3D Extractor software, which is based on the partial element equivalent circuits method. The equivalent circuits of the busbars and devices model are simulated in the electric simulator PSIM to analyze the effects of the parasitic inductance on the switching characteristics of the integrated gate commutatedthyristor (IGCT) in different topology positions. The simulation results agree well with the measured imped-ance analyzer results and the IGCT test results, which proves the effectiveness of the modeling method for the large, complex busbars.

  4. The tensor analyzing power Asub(yy) near s-wave levels

    In the neighborhood of an isolated resonance induced by s-wave particles, the component Asub(yy)(theta) of the tensor analyzing power is independent of the reaction angle theta. The constant value of Asub(yy)(theta) is a function of the level spin J and of the (l',s') configuration in the exit channel of the resonant amplitude. The use of this fact as a diagnostic tool in an analysis of the process is discussed and demonstrated with data available. It is also pointed out that efficient polarimeters can be constructed, which measure the quantity Asub(yy). (Auth.)

  5. Radioactivity level of the ambient environment of Anren bone-coal power station

    2002-01-01

    The radioactivity level of the ambient environment of Anren Bonc-coalPower Station (BCPS) was investigated systematically. The γ radiation dose ratelevel in the environment, the content of 238U and 226Ra in the ambient soil and thefarmland in the direction of downwind, the concentrations of 238U, 232Th, 226Ra, 40Kand 222Rn, as well as α potential energy in air, and the concentrations of natural Uand Th in effluent are all higher than the corresponding values of the reference site.The additional annual effective dose equivalent to the residents living in the housesmade of bone-coal cinder brick is 2.7mSv.

  6. Computational analysis of the curvature distribution and power losses of metal strip in tension levellers

    Tension levelling is employed in strip processing lines to minimise residual stresses resp. to improve the strip flatness by inducing small elasto-plastic deformations. To improve the design of such machines, precise calculation models are essential to reliably predict tension losses due to plastic dissipation, power requirements of the driven bridle rolls (located upstream and downstream), reaction forces on levelling rolls as well as strains and stresses in the strip. FEM (Finite Element Method) simulations of the tension levelling process (based on Updated Lagrangian concepts) yield high computational costs due to the necessity of very fine meshes as well as due to the severely non-linear characteristics of contact, material and geometry. In an evaluation process of hierarchical models (models with different modeling levels), the reliability of both 3D and 2D modelling concepts (based on continuum and structural elements) was proved by extensive analyses as well as consistency checks against measurement data from an industrial tension leveller. To exploit the potential of computational cost savings, a customised modelling approach based on the principle of virtual work has been elaborated, which yields a drastic reduction of degrees of freedom compared to simulations by utilising commercial FEM-packages.

  7. A new three-level current-source PWM inverter and its application for grid connected power conditioner

    This paper presents a novel topology of a three-level current-source PWM inverter totally driven by using single gate-drive power supply used for a grid connected inverter. The great feature of the proposed inverter circuit is that all of the power switches are connected on common-source or common-emitter configuration. Using this common-source current-source inverter (CS-CSI) the number of gate-drive power supply can dramatically be reduced into only a single power source without using bootstrap technique or many isolated power supplies. Operation of the proposed new inverter was tested by using computer simulation and experimentally. The simulation and experimental results proved that the inverter works properly generate a three-level output current waveform and inject a sinusoidal current into power grid with unity power factor operation. During grid connected operation, almost all harmonic orders are suppressed by using an additional harmonic suppression technique.

  8. Design of LCL-Filter Based Three-level Active Power Filter

    Shilan Chen

    2013-07-01

    Full Text Available This paper proposes an improved design of LCL-Filters for Three-Level Shunt Active power filters (APF. Available design principles are presented to achieve high compensation bandwidth and low switching frequency current. Then, affecitons of different parameters are taken into consideration of constraints on LCL-Filter design with detail analysis of ripple current. A simple and practical design procedure of LCL-Filter for Three-Level APF is subsequently proposed. The first step is to choose the resonant frequency of LCL-Filter according to the highest order harmonic needed to be compensated. Then it is aim to optimize the parameters of the LCL-Filter based on the design principles and constraints. The simulation results verify the effectiveness of the proposed method.

  9. Potential for de-regulated disposal of very low level wastes from nuclear power plants

    The purpose of the study discussed in this paper was to review the characteristics of low level waste streams generated in commercial nuclear power facilities to determine which may be suitable for disposal by methods other than transfer to a facility licensed by the Nuclear Regulatory Commission (NRC) and to evaluate the benefits, risks, and costs of exempting such very low level wastes (VLW) from the disposal requirements of 10 CFR Part 61. Of course, wastes that no longer require regulation of their radiological properties are still subject to the regulatory controls - federal, state, or local - that affect non-radioactive wastes of similar chemical and physical properties and similar origins. This study addressed radiological aspects only, and assumed, in its evaluations, that the wastes can and will be disposed of in accordance with all other applicable requirements. 4 references, 1 figure, 6 tables

  10. Trending of low level events and near misses to enhance safety performance in nuclear power plants

    The IAEA Safety Fundamentals publication, Safety of Nuclear Installations, Safety Series No. 110, states the need for operating organizations to establish a programme for the collection and analysis of operating experience in nuclear power plants. Such a programme ensures that operating experience is analysed, events important to safety are reviewed in depth, and lessons learned are disseminated to the staff of the organization and to relevant national and international organizations. As a result of the effort to enhance safety in operating organizations, incidents are progressively decreasing in number and significance. This means that in accordance with international reporting requirements the amount of collected data becomes less sufficient to draw meaningful statistical conclusions. This is where the collection and trend analysis of low level events and near misses can prove to be very useful. These trends can show which of the safety barriers are weak or failing more frequently. Evaluation and trending of low level events and near misses will help to prevent major incidents because latent weaknesses have been identified and corrective actions taken to prevent recurrence. This leads to improved safety and production. Low level events and near misses, which may reach several thousand per reactor operating year, need to be treated by the organizations as learning opportunities. A system for capturing these low level events and near misses truly needs to be an organization-wide system in which all levels of the organization, including contractors, participate. It is desirable that the overall operational experience feedback (OEF) process should integrate the lessons learned and the associated data from significant events with those of lower level events and near misses. To be able to effectively implement a process dealing with low level events and near misses, it is necessary that the organization have a well established OEF process for significant events

  11. Comparison of p53 levels in lymphocytes and in blood plasma of nuclear power plant workers

    p53 levels were assessed in lymphocytes and in blood plasma of workers from two Czech nuclear power plants (NPP): 114 subjects working in Temelin and 108 subjects working in Dukovany. Ionizing radiation (IR) exposure data were available for 64 and 59 subjects working in the monitored zones from the NPP in Temelin and Dukovany, respectively. The short-term doses of IR for these subjects were 0.01 and 0.12 mSv, and the long-term doses were 0.46 and 5.68 mSv, in the Temelin and Dukovany NPP, respectively. As a control group, 46 subjects living in Ceske Budejovice, a city nearby the Temelin NPP, were analyzed. The concentration of p53 in lymphocytes was significantly higher in workers from the monitored zone in the Dukovany NPP (median value 6.4 pg/μg protein, P < 0.001) than in workers from the Temelin NPP (3.2 pg/μg) as well as in the control group (3.5 pg/μg). In contrast, plasma levels of p53 were comparable in the control group (median value 116 pg/ml plasma) and workers from the monitored zone of Dukovany NPP (102 pg/ml), but lower in workers from Temelin NPP (5 pg/ml). Other factors affecting p53 levels were studied. Smoking resulted in increased p53 lymphocyte levels. The effect of polymorphisms in metabolic and DNA repair genes on p53 levels was analyzed. The correlation was found between p53 levels in lymphocytes and p53 codon 72 polymorphism in subjects working in NPPs, but not in the control group. The results of measurement p53 levels in lymphocytes suggest that this biomarker could reflect the short-term as well as long-term effects of low doses IR. Its impact on human health should be further explored

  12. Allowable Residual Contamination Levels in soil for decommissioning the Shippingport Atomic Power Station site

    As part of decommissioning the Shippingport Atomic Power Station, a fundamental concern is the determination of Allowable Residual Contamination Levels (ARCL) for radionuclides in the soil at the site. The ARCL method described in this report is based on a scenario/exposure-pathway analysis and compliance with an annual dose limit for unrestricted use of the land after decommissioning. In addition to naturally occurring radionuclides and fallout from weapons testing, soil contamination could potentially come from five other sources. These include operation of the Shippingport Station as a pressurized water reactor, operations of the Shippingport Station as a light-water breeder, operation of the nearby Beaver Valley reactors, releases during decommissioning, and operation of other nearby industries, including the Bruce-Mansfield coal-fired power plants. ARCL values are presented for 29 individual radionculides and a worksheet is provided so that ARCL values can be determined for any mixture of the individual radionuclides for any annual dose limit selected. In addition, a worksheet is provided for calculating present time soil concentration value that will decay to the ARCL values after any selected period of time, such as would occur during a period of restricted access. The ARCL results are presented for both unconfined (surface) and confined (subsurface) soil contamination. The ARCL method and results described in this report provide a flexible means of determining unrestricted-use site release conditions after decommissioning the Shippingport Atomic Power Station

  13. Evaluating the level and nature of sustainable development for a geothermal power plant

    The paper provides for an evaluation of the potential level and nature of sustainable development of the Sabalan geothermal power plant in NW Iran, to be operational in 2011. The paper achieves this by applying a mathematical model of sustainable development developed by the author (re: Phillips), in respect to the Environmental Impact Assessment (EIA) conducted by Yousefi et al. using the Rapid Impact Assessment Matrix (RIAM) methodology (re: Pastakia; Pastakia and Jensen). Using a model application methodology developed for the RIAM, the results indicated that the nature of sustainable development for Sabalan was considered to be very weak (S = 0.063). This was due to the imbalance between negative environmental impacts and positive socio-economic impacts deriving from the project. Further, when placed into context with a similar set of results obtained from the EIA of the Tuzla geothermal power plant by Baba also using the RIAM methodology, then the similarities between the results obtained raises some legimate questions as to the sustainable development credentials of geothermal power production. (author)

  14. What day-ahead reserves are needed in electric grids with high levels of wind power?

    Day-ahead load and wind power forecasts provide useful information for operational decision making, but they are imperfect and forecast errors must be offset with operational reserves and balancing of (real time) energy. Procurement of these reserves is of great operational and financial importance in integrating large-scale wind power. We present a probabilistic method to determine net load forecast uncertainty for day-ahead wind and load forecasts. Our analysis uses data from two different electric grids in the US with similar levels of installed wind capacity but with large differences in wind and load forecast accuracy, due to geographic characteristics. We demonstrate that the day-ahead capacity requirements can be computed based on forecasts of wind and load. For 95% day-ahead reliability, this required capacity ranges from 2100 to 5700 MW for ERCOT, and 1900 to 4500 MW for MISO (with 10 GW of installed wind capacity), depending on the wind and load forecast values. We also show that for each MW of additional wind power capacity for ERCOT, 0.16–0.30 MW of dispatchable capacity will be used to compensate for wind uncertainty based on day-ahead forecasts. For MISO (with its more accurate forecasts), the requirement is 0.07–0.13 MW of dispatchable capacity for each MW of additional wind capacity. (letter)

  15. What day-ahead reserves are needed in electric grids with high levels of wind power?

    Mauch, Brandon; Apt, Jay; Carvalho, Pedro M. S.; Jaramillo, Paulina

    2013-09-01

    Day-ahead load and wind power forecasts provide useful information for operational decision making, but they are imperfect and forecast errors must be offset with operational reserves and balancing of (real time) energy. Procurement of these reserves is of great operational and financial importance in integrating large-scale wind power. We present a probabilistic method to determine net load forecast uncertainty for day-ahead wind and load forecasts. Our analysis uses data from two different electric grids in the US with similar levels of installed wind capacity but with large differences in wind and load forecast accuracy, due to geographic characteristics. We demonstrate that the day-ahead capacity requirements can be computed based on forecasts of wind and load. For 95% day-ahead reliability, this required capacity ranges from 2100 to 5700 MW for ERCOT, and 1900 to 4500 MW for MISO (with 10 GW of installed wind capacity), depending on the wind and load forecast values. We also show that for each MW of additional wind power capacity for ERCOT, 0.16-0.30 MW of dispatchable capacity will be used to compensate for wind uncertainty based on day-ahead forecasts. For MISO (with its more accurate forecasts), the requirement is 0.07-0.13 MW of dispatchable capacity for each MW of additional wind capacity.

  16. A stationary reference frame current control for a multi-level H-bridge power converter for universal and flexible power management in future electricity network

    Ciobotaru, Mihai; Iov, Florin; Zanchetta, Pericle;

    2008-01-01

    converters for grid connection of renewable sources will be needed. These power converters must be able to provide intelligent power management as well as ancillary services. This paper assesses a control method based on the stationary reference frame with Proportional-Resonant current controllers for a...... multi-level cascaded H-bridges power converter used for grid applications. Harmonic content in the Point of Common Coupling, system response for bidirectional power flow, voltage and frequency excursions as well as voltage unbalances and asymmetries and low voltage ride-though capabilities are studied....

  17. High Partial Discharge Levels in Nuclear Power Plant Turbo-Generator

    On-line measurement of partial discharge (PD) is commonly known method for assessment of armature winding condition. Since it can be carried out while the machine is in operation, it is considered by many to be the most realistic one. PD pulses are forwarded to measuring instrument using capacitive couplers connected to machine stator phase winding. Magnitude, polarity and phase angle relative to phase-to-ground voltage are measured for every pulse and further analysed by statistical approach. A number of problems with armature winding can be registered and diagnosed by PD method. The paper presents results of PD measurement and its analysis in case of large synchronous turbo-generator, 812 MVA, 21 kV, cosφ=0.85, 50 Hz, 1500 rpm, manufactured in 1979 and installed in nuclear power plant Krsko, Slovenia. The generator is cooled with hydrogen, with armature winding directly cooled by water. The turbine-generator set's rated power has been increased from original 660 MW twice: in 2000 up to 690 MW and in 2004 up to 730 MW. There have been no modifications on generator regarding the power increase. Paper presents results of PD measurements in NPP Krsko carried out by authors since 2001. Previously measured high PD levels have been verified and monitored after installation of on-line PD monitoring system in 2004. All other performed off-line measurements have not shown any signs of severe deterioration or other problem in generator stator winding insulation. Registered PDs were almost 8 times higher than 95% of typical PDs measured for similar turbo-generators, their magnitude varies with ratio 1:100, their phase distribution lies around 0 degrees and 180 degrees, (indicating that their cause is outside of slots and of mechanical origin), their main source migrates from phase to phase, they are cross-coupling to other phases (indicating that their origin lies in part of generator where all three phases are close) and their phase occurrence varies with constant active

  18. Level 1 shutdown and low power operation of Mochovce NPP, Unit 1, Slovakia

    The paper presents general approach, used methods and form of documentation of the results that have been applied within the shutdown and low power PSA (SPSA) study for Mochovce NPP, Unit 1, Slovakia. The SPSA project was realized by VUJE Trnava Inc., Slovakia in 2001-2002 years. The Level 1 SPSA study for Mochovce NPP Unit 1 covers internal events as well as internal (fires, floods and heavy load drop) and external (aircraft crash, extreme meteorological conditions, seismic event and influence of surrounding industry) hazards. Mochovce NPP consists of two operating units equipped with VVER 440/V213 reactors safety upgraded before construction finishing and operation start. 87 safety measures based on VVER 440 operational experience and international mission insights were implemented to enhance its operational and nuclear safety. The SPSA relates to full power PSA (FPSA) as a continuation of the effort to create a harmonized level 1 PSA model for all operational modes of the plant with the goal to use it for further purposes as follows: Real Time Risk Monitor, Maintenance Optimization, Technical Specifications Optimization, Living PSA. (author)

  19. Grid Connection of Wave Power Farm Using an N-Level Cascaded H-Bridge Multilevel Inverter

    Rickard Ekström

    2013-01-01

    Full Text Available An N-level cascaded H-bridge multilevel inverter is proposed for grid connection of large wave power farms. The point-absorber wave energy converters are individually rectified and used as isolated DC-sources. The variable power characteristics of the wave energy converters are discussed, and a method of mitigating this issue is demonstrated. The complete power control system is given in detail and has been experimentally verified for a single-phase setup of the 9-level inverter. Theoretical expressions of the power sharing between multilevel cells are derived and show good correspondence with the experimental results.

  20. Microwave cytotoxicity: lack of in vitro evidence of nonthermal effects at high power levels

    A unique cylindrical microwave cavity chamber for the exposure of mammalian cells was designed and built. The cavity was used to determine whether or not microwaves (896 or 434-460 MHz) are capable of affecting cellular survival via nonthermal mechanisms other than those resulting from equivalent thermal exposures. Chinese hamster ovary (HA-1) cells or radiation-induced fibrosarcoma (RIF) mouse cells were grown directly on gold-plated copper disks to assure optimum heat dissipation and accurate thermal dosimetry. The temperature was controlled precisely (+/-0.1/sup o/C and was measured continuously during microwave exposures. Microwave power levels of 135 W/cm3 of absorbed power maintained for 30 min caused no discernible decrease in cellular survival of proliferating cells compared to that measured in appropriate heat controls over a temperature range of 12 to 46/sup o/C. In addition, RIF mouse cells were exposed similarly in Hanks' balanaced salt solution (HBSS). Again, no additional decrease in survival beyond that due to heating was observed for microwave exposure in full medium; however, a significant decrease in survival was noted when cells were treated in HBSS which was at pH 6.9-7.2. This phenomenon may have implications in tumors with significant portions of the population at low pH or with low nutrient concentrations. Since these absorbed power levels are at least two orders of magnitude greater than those that will be necessary to hear and maintain tumors at hyperthermic treatment temperatures for cancer therapy, these results suggest that cellular destruction in proliferating cells can be predicted by the heat effect and that any microwave-specific nonthermal effects encountered in vivo will likely be due to problems of thermal dosimetry of physiological factors related to this mode of heat distribution

  1. Evaluation of environmental tritium level in the area of Cernavoda Nuclear Power Plant

    This work is a continuation of the study entitled Evaluation of environmental tritium levels before and after start of a new tritium source for model verification' that commenced two years ago as part of an European research contract having as objective the 'Investigations and Modelling of the Dynamics of Environmental HT/HTO/OBT Levels Resulting from the Tritium Releases'. The aim of this study was to evaluate the environmental tritium level in pre-operational stage of Cernavoda Nuclear Power Plant and the dynamics of variation of tritium concentration in the first operational years of NPP, for determination of site-specific transfer parameters and model validation. Representative samples for Cernavoda area were analyzed; - air humidity; - water from Danube River, Danube-Black Sea Canal and lakes; - drinking, rain and snow water; - HTO concentration in soils at different depths; - tissue free water tritium in vegetal and animal foodstuffs relevant for human diets like cereals (wheat, maize, barley). vegetables (potatoes, tomato, cabbage, onion, bean), grapes and wine. The mean concentration of tritium obtained in 1996 for these types of measurements is presented. The values of tritium concentration in air, water, soil and plants are as low as for areas without contaminating sources. The operation in 1996 of the Cernavoda NPP did not modify the tritium environmental level. (authors)

  2. Design and Analysis of Multi Level D-STATCOM to Improve the Power Quality

    Dinesh. Badavath,; Mr. T. Subramanya Sastry

    2014-01-01

    In the last decade, the electrical power quality issue has been the main concern of the power companies. Power quality is defined as the index which both the delivery and consumption of electric power affect on the performance of electrical apparatus. From a customer point of view, a power quality problem can be defined as any problem is manifested on voltage, current, or frequency deviation that results in power failure. The power electronics progressive, especially in flexib...

  3. Application of Backstepping to the Virtual Flux Direct Power Control of Five-Level Three-Phase Shunt Active Power Filter

    Bouzidi Mansour

    2014-03-01

    Full Text Available This paper proposes a virtual flux direct power control-space vector modulation combined with backstepping control for three-phase five-level neutral point clamped shunt active power filter. The main goal of the proposed active filtering system is to eliminate the unwanted harmonics and compensate fundamental reactive power drawn from the nonlinear loads. In this study, the voltage-balancing control of four split dc capacitors of the five-level active filter is achieved using five-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. The obtained results showed that, the proposed multilevel shunt active power filter with backstepping control can produce a sinusoidal supply current with low harmonic distortion and in phase with the line voltage.

  4. Development Efforts Expanded in Ion Propulsion: Ion Thrusters Developed With Higher Power Levels

    Patterson, Michael J.; Rawlin, Vincent K.; Sovey, James S.

    2003-01-01

    The NASA Glenn Research Center was the major contributor of 2-kW-class ion thruster technology to the Deep Space 1 mission, which was successfully completed in early 2002. Recently, NASA s Office of Space Science awarded approximately $21 million to Glenn to develop higher power xenon ion propulsion systems for large flagship missions such as outer planet explorers and sample return missions. The project, referred to as NASA's Evolutionary Xenon Thruster (NEXT), is a logical follow-on to the ion propulsion system demonstrated on Deep Space 1. The propulsion system power level for NEXT is expected to be as high as 25 kW, incorporating multiple ion thrusters, each capable of being throttled over a 1- to 6-kW power range. To date, engineering model thrusters have been developed, and performance and plume diagnostics are now being documented. The project team-Glenn, the Jet Propulsion Laboratory, General Dynamics, Boeing Electron Dynamic Devices, the Applied Physics Laboratory, the University of Michigan, and Colorado State University-is in the process of developing hardware for a ground demonstration of the NEXT propulsion system, which comprises a xenon feed system, controllers, multiple thrusters, and power processors. The development program also will include life assessments by tests and analyses, single-string tests of ion thrusters and power systems, and finally, multistring thruster system tests in calendar year 2005. In addition, NASA's Office of Space Science selected Glenn to lead the development of a 25-kW xenon thruster to enable NASA to conduct future missions to the outer planets of Jupiter and beyond, under the High Power Electric Propulsion (HiPEP) program. The development of a 100-kW-class ion propulsion system and power conversion systems are critical components to enable future nuclear-electric propulsion systems. In fiscal year 2003, a team composed of Glenn, the Boeing Company, General Dynamics, the Applied Physics Laboratory, the Naval Research

  5. A Battery-less Grid Connected Photovoltaic Power generation using Five-Level Common-Emitter Current-Source Inverter

    Suroso Suroso

    2014-12-01

    Full Text Available Renewable power generation using photovoltaic is very interesting to be developed to deal with the problems of conventional energy sources and environmental issues. The photovoltaic power generation can operate both in stand-alone and grid-connected operations. This paper presents an application of the five-level common-emitter current-source inverter (CE-CSI for grid connected photovoltaic system without batteries as energy storage system. In the proposed system, the five-level CE-CSI works generating a sinusoidal output current from photovoltaic system to be injected into the power grid. The transformer is used in the system to step-down the grid voltage to meet the voltage level of the photovoltaic system, and also works as a galvanic insulation between the power grid and the inverter system. Two conditions of the power grid voltage, i.e. a pure sinusoidal and a distorted power grid, are tested through computer simulation using PSIM software. Furthermore, experimental test result of the five-level inverter is also presented. The test results show that the five-level CE-CSI works well injecting a sinusoidal current into the power grid with low harmonic contents, and with unity power factor operation. The results also show that the distorted grid voltage affects the harmonic contents of the current injected by the inverter.

  6. Low Level Event and Near Miss Process for Nuclear Power Plants: Best Practices

    The IAEA programme on the operational safety of nuclear power plants gives priority to the development and promotion of the proper use of IAEA safety standards through the provision of assistance to Member States in the application of safety standards, the performance of safety review missions and the conduct of training activities based on safety standards. A number of IAEA safety standards and nuclear safety publications discuss the processes that need to be put into place for the feedback and analysis of operating experience (OE) at nuclear power plants. These include: Fundamental Safety Principles (IAEA Safety Standards Series No. SF-1), Safety of Nuclear Power Plants: Commissioning and Operation (IAEA Safety Standards Series No. SSR-2/2), Application of the Management System for Facilities and Activities (IAEA Safety Standards Series No. GS-G-3.1) and A System for the Feedback of Experience from Events in Nuclear Installations (IAEA Safety Standards Series No. NS-G-2.11). Additionally, several IAEA TECDOCs cover many aspects of the establishment, conduct and continuous improvement of an OE programme at nuclear power plants, including the consideration of low level events (LLEs) and near misses (NMs). Although these IAEA safety standards and nuclear safety publications have been in existence for several years, 70 per cent of the IAEA Operational Safety Review Team (OSART) missions carried out at nuclear power plants between 2006 and 2010 identified weaknesses in the reporting and analysis process for LLEs and NMs. In fact, this has been one of the recurring issues most often identified in the area of OE during these missions. These weaknesses have been further confirmed by most of the IAEA Peer Review of the Operational Safety Performance Experience (PROSPER) missions that have been conducted to date. Finally, the IAEA International Nuclear Safety Group, in their report entitled Improving the International System for Operating Experience Feedback (INSAG-23

  7. Power

    Bowles, Samuel; Gintis, Herbert

    2007-01-01

    We consider the exercise of power in competitive markets for goods, labour and credit. We offer a definition of power and show that if contracts are incomplete it may be exercised either in Pareto-improving ways or to the disadvantage of those without power. Contrasting conceptions of power including bargaining power, market power, and consumer sovereignty are considered. Because the exercise of power may alter prices and other aspects of exchanges, abstracting from power may miss essential a...

  8. Adaptative control with non-minimum phase system. Application to level control in PWR power plant steam generator

    This thesis presents the proposal for a water control level method likely to improve performance, especially at low power. Particular problems are analyzed in detail. Finally, computerized simulations are presented; they confirm the algorithm performance

  9. A General Framework for Power Analysis to Detect the Moderator Effects in Two- and Three-Level Cluster Randomized Trials

    Dong, Nianbo; Spybrook, Jessaca; Kelcey, Ben

    2016-01-01

    The purpose of this study is to propose a general framework for power analyses to detect the moderator effects in two- and three-level cluster randomized trials (CRTs). The study specifically aims to: (1) develop the statistical formulations for calculating statistical power, minimum detectable effect size (MDES) and its confidence interval to…

  10. Study and Analysis of a Natural Reference Frame Current Controller for a Multi-Level H-Bridge Power Converter

    Ciobotaru, Mihai; Iov, Florin; Zanchetta, P.;

    2008-01-01

    natural reference frame controller, based on proportional-resonant (PR) technique, for a multi-level H-bridge power converter for Universal and Flexible Power Management in Future Electricity Network. The proposed method is tested in terms of harmonic content in the Point of Common Coupling (PCC), voltage...

  11. Managing autonomy levels in the SSM/PMAD testbed. [Space Station Power Management and Distribution

    Ashworth, Barry R.

    1990-01-01

    It is pointed out that when autonomous operations are mixed with those of a manual nature, concepts concerning the boundary of operations and responsibility become clouded. The space station module power management and distribution (SSM/PMAD) automation testbed has the need for such mixed-mode capabilities. The concept of managing the SSM/PMAD testbed in the presence of changing levels of autonomy is examined. A knowledge-based approach to implementing autonomy management in the distributed SSM/PMAD utilizing a centralized planning system is presented. Its knowledge relations and system-wide interactions are discussed, along with the operational nature of the currently functioning SSM/PMAD knowledge-based systems.

  12. Several High Level Issues in Reliability Assessment of Safety-Critical Software in Nuclear Power Plants

    Kim, Man Cheol; Jang, Seung Cheol [KAERI, Daejeon (Korea, Republic of)

    2011-08-15

    For the purpose of developing a consensus method for the reliability assessment of safety-critical digital instrumentation and control systems in nuclear power plants, several high level issues in reliability assessment of the safety-critical software based on Bayesian belief network modeling and statistical testing are discussed. Related to the Bayesian belief network modeling, the relation between the assessment approach and the sources of evidence, the relation between qualitative evidence and quantitative evidence, and how to consider qualitative evidence are discussed. Related to the statistical testing, the need of the consideration of context-specific software failure probabilities and the inability to perform a huge number of tests in the real world are discussed. The discussions in this paper are expected to provide a common basis for future discussions on the reliability assessment of safety-critical software.

  13. Levelized Cost of Energy Analysis of a Wind Power Generation System at Búrfell in Iceland

    Birgir Freyr Ragnarsson

    2015-09-01

    Full Text Available Wind energy harnessing is a new energy production alternative in Iceland. Current installed wind power in Iceland sums to 1.8 MW, which in contrast is 0.1% of the country’s total electricity production. This article is dedicated to the exploration of the potential cost of wind energy production at Búrfell in the south of Iceland. A levelized cost of energy (LCOE approach was applied to the estimation of the potential cost. Weibull simulation is used to simulate wind data for calculations. A confirmation of the power law is done by comparing real data to calculated values. A modified Weibull simulation is verified by comparing results with actual on-site test wind turbines. A wind farm of 99MWis suggested for the site. Key results were the capacity factor (CF at Búrfell being 38.15% on average and that the LCOE for wind energy was estimated as 0.087–0.088 USD/kWh (assuming 10% weighted average cost of capital (WACC, which classifies Búrfell among the lowest LCOE sites for wind energy in Europe.

  14. A Demonstration of Spectral Level Reconstruction of Intrinsic $B$-mode Power

    Pal, Barun

    2016-01-01

    We investigate the prospects and consequences of the spectral level reconstruction of primordial $B$-mode power by solving the systems of linear equations assuming that the lensing potential together with the lensed polarization spectra are already in hand. We find that this reconstruction technique may be very useful to have an estimate of the amplitude of primordial gravity waves or more specifically the value of tensor to scalar ratio. We also see that one can have cosmic variance limited reconstruction of the intrinsic $B$-mode power up to few hundred multipoles ($\\ell\\sim500$) which is more than sufficient to have an estimate of the tensor to scalar ratio. Since the small scale cosmic microwave background (CMB henceforth) anisotropies are not sourced by the primordial gravity waves generated during inflation. We also find that the impact of instrumental noise may be bypassed within this reconstruction algorithm. A simple demonstration for the nullification of the instrumental noise anticipating COrE like...

  15. Low Power Analysis of Network-Level On-chip communication using Asynchronous AMBA protocol

    E. Sakthivel

    2012-07-01

    Full Text Available Network on-chip (NoC is a novel structuraldesign template, which can be defied for complicatedsystem level on-chip design. NoC has a potential tolimit and present the bus-based communication. In thispaper, the crisis to discuss is Low power consumptionin an Asynchronous Network on-chip (NoC levelcommunication. NoC is implemented using FPGAwhich has less fabrication cost and reduces thecomplexity. An Asynchronous NoC has beenimplemented in Spartan kit using Xilinx FPGA ISEtools and its network interface is AdvancedMicrocontroller Bus Architecture (AMBA whichfeatures numerous bus masters and a sole clock edgeevolution and so on. Here the AMBA highperformance 32-bit AHB bus is employed in which ithas a high clock frequency system and it is the heart ofour bus system. To accomplish low power consumptionby interfacing SoC with AMBA- AHB protocol. TheAHB model and an Asynchronous NoC are employedand executed using VHDL programming module

  16. Determination of 93Zr in medium and low level radioactive wastes from Brazilian nuclear power plants

    The majority of long-lived radionuclides produced in the nuclear power plants can be regarded as difficult-to-measure radionuclides (RDM), hence chemical separation is necessary before the nuclear measurement of them. The zirconium isotope 93Zr is a long-lived pure β-particle-emitting radionuclide produced from 235U fission and from neutron activation of the stable isotope 92Zr and thus occurring as one of the radionuclides found in nuclear reactors. Due to its long half-life, 93Zr is one of the radionuclides of interest for the performance of assessment studies of waste storage or disposal. Two different methodologies based on extractive resins and LSC and ICP-MS techniques that enables the 93Zr determination in medium (ILW) and low level (LLW) radioactive wastes samples from Brazilian nuclear power plants has been developed in our laboratory. Analyzing real samples 65% and 75% chemical yields for 93Zr recovery were achieved for ICP-MS and LSC techniques, respectively. The detection limits were 0.045 μg.L-1 for ICP-MS and 0.05 Bq.L-1 for LSC techniques. (author)

  17. Exergetic optimization of single level combined gas-steam power plants considering different objective functions

    Bracco, Stefano [Department of Turbomachinery, Energy Systems and Transportation, University of Genova, Via Montallegro 1, 16145 Genova (Italy); Siri, Silvia [Department of Communications, Computer and Systems Science, University of Genova, Via Opera Pia 13, 16145 Genova (Italy)

    2010-12-15

    Combined cycle power plants have been studied in this paper with the aim of optimizing the heat recovery steam generator using a first and second law approach. To this end, a mathematical model has been developed for determining the optimal steam pressure in a one pressure level heat recovery steam generator, considering that the gas turbine is known. Different objective functions have been analysed in this study, some of which refer only to the exergy balance of the heat recovery steam generator while others involve the whole bottoming cycle. Some constraints for the operating parameters of the power plant have also been taken into account, regarding for instance the steam quality at the turbine outlet and the steam turbine blade height. Some numerical results have been reported in the paper, comparing the different objective functions for heat recovery steam generators coupled with several gas turbines; the developed parametric analysis has been performed in order to evaluate the influence of some parameters on both the heat recovery steam generator and the whole bottoming cycle. (author)

  18. Some Comparisons of Measured and Predicted Primary Radiation Levels in the Aagesta Power Plant

    Neutron fluxes and gamma exposure rates in the primary shields of the Aagesta nuclear plant have been measured and the results compared with values predicted during shield design, and with values obtained later by the NRN bulk shielding code. The input data for the problems are given. The radial predictions are conservative by a factor of not more than 2 close to the reactor and by an unknown, higher factor further out. The conservatism is explainable by the differences between the true local conditions and core power distributions and those assumed in the predictions. The axial flux levels based on streaming calculations are found to agree quite well with the estimated values. The conservatism here is not so large and it seems to be necessary to be very careful when handling streaming problems. The experience gained shows that a power plant is less suitable for studying the accuracy of the shield design codes as such, but the practical results from the combined application of massive shield codes and void streaming predictions to complicated problems give information about the true degree of conservatism present

  19. Efficiency at maximum power of a heat engine working with a two-level atomic system.

    Wang, Rui; Wang, Jianhui; He, Jizhou; Ma, Yongli

    2013-04-01

    We consider the finite-time operation of a quantum heat engine whose working substance is composed of a two-level atomic system. The engine cycle, consisting of two quantum adiabatic and two quantum isochoric (constant-frequency) processes and working between two heat reservoirs at temperatures T(h) and T(c)(cycle. By optimizing the power output with respect to two frequencies, we obtain the efficiency at maximum power output (EMP) and analyze numerically the effects of the times taken for two adiabatic and two isochoric processes on the EMP. In the absence of internally dissipative friction, we find that the EMP is bounded from the upper side by a function of the Carnot efficiency η(C), η(+)=η(C)(2)/[η(C)-(1-η(C))ln(1-η(C))], with η(C)=1-T(c)/T(h). This analytic expression is confirmed by our exact numerical result and is identical to the one derived in an engine model based on a mesoscopic or macroscopic system. If the internal friction is included, we find that the EMP decreases as the friction coefficient increases. PMID:23679385

  20. Management of Low Level Rad-Waste Arising From Nuclear Power Stations in Japan

    In nuclear power stations in Japan, in order to reduce radioactivity release into the environment based on the concept of ALARA, various improvements of the gaseous and liquid waste treatment systems have been made in both aspects of facilities and operations as follows: In order to reduce the release of gaseous waste, the following facilities were introduced: Charcoal bed typed noble gas holdup facility, Clean steam supply system for turbine gland seal, No leak typed valve In order to reduce the release of liquid waste, the following measures were taken: Evaporating floor drain, Evaporating laundry drain;, Demoralizing plant surplus water by a mix bed typed ion exchange resin. As a result of these counter measures, the release of gaseous and liquid radioactivity into the environment has been reduced gradually, and is now virtually 'zero' as shown in Islet. 1. Contrary to reduction in radioactivity release into the environment, residual radioactivity inside nuclear power station has made consequent increase of low level radioactive wastes in the form of solid

  1. INFLUENCES OF THE PURCHASING POWER CHANGE ON THE EVOLUTION OF THE AGROALIMETARY MARKETS ON EUROPEAN UNION LEVEL

    Laura Catalina Timiras

    2013-01-01

    This paper aims to identify the manifested connection between the dynamics of the population purchasing power and the dynamic of agroalimentary markets in general as well as by product types on European Union level. Based on the last data supplied by Eurostat 2013, using the specific methods for studying the correlations, we have detected that increases and decreases of the purchasing power generated similar changes on agroalimentary markets level from the point of view of achieved sales in m...

  2. INFLUENCES OF THE PURCHASING POWER CHANGE ON THE EVOLUTION OF THE AGROALIMETARY MARKETS ON EUROPEAN UNION LEVEL

    Laura Catalina Timiras

    2014-01-01

    This paper aims to identify the manifested connection between the dynamics of the population purchasing power and the dynamic of agroalimentary markets in general as well as by product types on European Union level. Based on the last data supplied by Eurostat 2013, using the specific methods for studying the correlations, we have detected that increases and decreases of the purchasing power generated similar changes on agroalimentary markets level from the point of view of achieved sales in m...

  3. Analysis of SG level control system stability after power uprating at Kori 3 and 4 and Ygn 1 and 2

    Poor control of the steam generator water level in the secondary system of a nuclear power plant after power uprating at Kori Unit 3 and 4 and Younggwang Unit 1 and 2 can lead to frequent reactor shutdowns. Such shutdowns are caused by violation of safety limits on the water level. The performance of steam generator level control system has been evaluated. The purposes of simulation analysis are to provide the expected plant responses as follows; 1) To support training plant operators and engineering personnel in preparation for performing the actual site test. 2) For evaluation to determine appropriate SG level control system setpoints in advance of performing the site startup test

  4. Impacts from a fossil fuel power plant on ozone levels in Memphis, Tennessee

    The Tennessee Valley Authority (TVA) Allen power plant is located on the Mississippi River in the southwest corner of Memphis, Tennessee. Allen has three coal-fired cyclone boilers with a rated capacity of 272 MW each. It is a Phase 2 plant under Title IV of the Clean Air Act and is the largest single source of NOx in the Memphis area. TVA plans to reduce Allen NOx emissions through a combination of burning low-sulfur coal (which has the benefit of reducing NOx emissions while also reducing SO2 emissions) and installing gas re-burn technology. A modeling study using the SAI, Inc., UAM-V photochemical model was conducted to examine the potential impacts of NOx reductions on ozone levels in the Memphis area. A series of four model simulations were made in which different Allen emissions scenarios were examined. The focus period of the photochemical modeling was 11--14 July 1995 when measurements in and near Memphis indicated peak hourly ozone levels of 135--140 ppb. This analysis primarily examined computed impacts within 50 km of Memphis. Allen was computed to contribute as much as 20--30 ppb to ground ozone levels 20-50 km downwind using its NOx emission rate before Title IV compliance. After compliance it was computed to contribute only about 10--20 ppb. At the same time, maximum daily ozone reductions due to Allen NOx titration of ozone were between 30 and 60 ppb. These benefits will be reduced by 30--50% after Title IV compliance, and are expected to occur within 30 km of the plant. More model grid cells indicated dis-benefits (net ground-level ozone increases) than benefits on three of the four episode days using the Title IV compliance emission rate. Significant ozone dis-benefits were expected because of the well-documented NO titration of ozone within plumes having a high ratio of NO to volatile organic compounds

  5. Efficiency improvement of transport service by trolley buses based on the levels of their power demand

    V. V. Aulin

    2014-12-01

    Full Text Available Purpose. Use efficiency improvement of trolley buses in passenger traffic based on power levels of electric energy input and terms adjustment of their maintenance. Methodology. In order to achieve this goal conformance of electric energy input by trolleybus to the transported amount of passengers taking into account characteristics of the route is offered to establish. The major indicators of the trolleybus operation are: speed of a race on lines, number of tractive motor firing, voltage and amperage in the network that were taken with accountants from a dashboard. Research results were tabulated and recorded with DVR. Along with the study of power consumption of electric energy input by a trolleybus passenger count was carried out too. Findings. The directly proportional dependence between the level of energy consumption by a trolleybus and the number of passengers for constant performance route was determined. Originality. As the criteria for evaluating the effectiveness of the trolleybus operation on the route is proposed to use the ratio between electricity consumption and number of passengers for these characteristics of the route. This is confirmed experimentally. The obtained formulas give the possibility to balance the force work and consequently the volume of energy consumption during the trolleybus movement on the rise and the descent. Practical value. The proposed criterion can be used to adjust the terms of maintenance on the individual program, that means individual maintenance (IM. Type of work performed at the IM should be determined on the basis of diagnostic data of the vehicle (V. The principles of IM were formulated: 1 the primary task is planned and preventative strategy to identify and eliminate troubleshooting and technical actions; 2 operational control of the vehicle (V technical condition on the basis of prediction of its state using the proposed criteria, that takes into account the dependence of power consumption to

  6. POWER QUALITY ENHANCEMENT USING 7 LEVEL CASCADED H - BRIDGE INVERTER BASED D - STATCOM WITH PQ THEOR Y

    Bhushan P. Kadu

    2015-06-01

    Full Text Available This paper presents an investigation of Seven - Level H – bridge Inverter is used in a Distribution Static Compensator (DSTATCOM in Power System (PS, making use of seven level cascaded inverter benefits of low harmonics distortion, reduced number of switches to achieve the seven - level inverter output over the conventional cascaded seven level inverter and reduced switching losses . In order to improve the power factor, compensate the reactive power and suppress the total harmonics distortion (THD drawn from a Non - Liner Diode Rectifier Load (NLDRL of DSTATCOM, we propose a Level Shift Pulse Width Modulation (LSPWM technique is used as control for the switches of H – bridge Inverter. The PQ theory is used to generate the reference compensating current for DSTATCOM . The proposed system is simulated in the MATLAB environment using simulink and results are discussed

  7. A RESEARCH TO HIGH-PERFORMANCE MULTI-LEVEL SINGLEPHASE AC/DC POWER FACTOR CORRECT SWITCHING CONVERTER

    Gao Chao

    2008-01-01

    This letter studies and analyzes the working features of main circuit of tri-level boost Power Factor Correct (PFC) converter and the advantages of tri-level switch converter in aspects of bearing high-voltage of power components,overall system loss and magnetic component selection based upon the single-level boost PFC switch converter. Besides,relying on the application of mi-croprocessor in power converter technology and DSP (Digital Signal Processing) chip's strong cal-culating capacity,the letter presents the adoption of modified scheme of tri-level boost PFC converter under the control of predictive control algorithm. Moreover,the operating principle and control method are specified,the results of circuit test and analysis are provided and the advantages of pre-dictive control technology-based multi-level boost PFC converter is verified.

  8. Use of Three-Level Power Converters in Wind-Driven Permanent-Magnet Synchronous Generators with Unbalanced Loads

    Ming-Hung Chen

    2015-01-01

    This paper describes the design and implementation of three-level power converters for wind-driven permanent-magnet synchronous generators with unbalanced loads. To increase voltage stress and reduce current harmonics in the electrical power generated by a wind generator, a three-phase, three-level rectifier is used. Because a synchronous rotating frame is used on the AC-input side, the use of a neutral-point-clamped controller is proposed to increase the power factor to unity and reduce curr...

  9. Clearance of very low level radioactive waste in spanish nuclear power plants

    According to present Spanish legislation a radioactive waste is defined as any material or waste product, without any possible planned use, that contains or is contaminated with radionuclides in concentrations or activity levels higher than those established by the Regulatory Authorities. Legally, this situation allows to develop a conventional management of very low level radioactive waste, by checking the negligibility of their radiological impact, and thus obtaining the corresponding Authorization to treat them as conventional waste. This presentation describes the clearance project of contaminated oils from spanish nuclear power plants. The on-site management includes: -) preliminary settling, centrifugation and filtration; -) oil purification; and -) radiological characterization. The off-site management includes the following operations: -) transportation to the facility where treatment is developed (dilution); -) temporary storage (decay); -) transportation to the place where final management is carried out; -) oil burning (dilution); and management of ashes and other combustion products. An annual amount of 70 m3/year (63 MBq) of very low contaminated oil with a specific concentration of 1 Bq/g could be disposed off. (A.C.)

  10. Measurement and release of low-level contaminated materials from nuclear power plants into environment

    Release of low-level contaminated solid materials originated from the operation or decommissioning of nuclear power plants into the environment for their recycling, reuse or liquidation is one of the main ways for the minimization of radioactive wastes production. Regulated measurement of contamination and quantitative determination of radionuclides in materials to be released are relatively complicated but manageable processes. AllDeco operates 2 measuring devices for materials release. For this purpose measuring chambers of RTM type are used for the determination of total gamma activity of radionuclides in materials. Activities of alpha and beta radionuclides are calculated by statistical results processing based on radionuclide vectors established in the laboratory for samples of similar materials. Possible spatial inhomogeneities of the contamination in measured materials can be identified by the devices software. The measurement of total gamma activity is completed by controlling spectrometric determination of present gamma radionuclides using NaI or Ge detectors. Limits for the release are measured and observed according to assigned accuracy for measuring chambers as authorized official measures. The stipulated reference levels are controlled by selective measurements of the surface alpha and beta activities and by the determination of the ratio of main gamma radionuclides. (authors)

  11. Dependence of form factors for power and temperature on time and power level at FDR-type reactors

    In order to test neutron power and fuel temperature form factor variations in a reactor core during operational transients several calculations were performed by means of the dynamics program KINE. This code includes one-dimensional time-dependent feedbacks in order to check-point reactor model calculations. It could be shown that the variation of the form factor was positive or negative dependent on the transient, but not more than 3%. At a hypothetical accident with an unrealistic increase of power by 70% an increase of the form factors by about 10% resulted, which is small compared to the safety margins in quasistationary accident analyses with a point model. (orig.)

  12. Output Feedback Dissipation Control for the Power-Level of Modular High-Temperature Gas-Cooled Reactors

    Zhe Dong

    2011-11-01

    Full Text Available Because of its strong inherent safety features and the high outlet temperature, the modular high temperature gas-cooled nuclear reactor (MHTGR is the chosen technology for a new generation of nuclear power plants. Such power plants are being considered for industrial applications with a wide range of power levels, thus power-level regulation is very important for their efficient and stable operation. Exploiting the large scale asymptotic closed-loop stability provided by nonlinear controllers, a nonlinear power-level regulator is presented in this paper that is based upon both the techniques of feedback dissipation and well-established backstepping. The virtue of this control strategy, i.e., the ability of globally asymptotic stabilization, is that it takes advantage of the inherent zero-state detectability property of the MHTGR dynamics. Moreover, this newly built power-level regulator is also robust towards modeling uncertainty in the control rod dynamics. If modeling uncertainty of the control rod dynamics is small enough to be omitted, then this control law can be simplified to a classical proportional feedback controller. The comparison of the control performance between the newly-built power controller and the simplified controller is also given through numerical study and theoretical analysis.

  13. Operating and Loading Conditions of a Three-Level Neutral-Point-Clamped Wind Power Converter Under Various Grid Faults

    Ma, Ke; Liserre, Marco; Blaabjerg, Frede

    2014-01-01

    In order to fulfill the growing demands from the grid side, full-scale power converters are becoming popular in the wind turbine system. The low-voltage ride-through (LVRT) requirements may not only cause control problems but also result in overstressed components for the power converter. However......, the thermal loading of the wind power converter under various grid faults is still not yet clarified, particularly at megawatt power level. In this paper, the impacts by three types of grid faults to a three-level neutral-point-clamped (3L-NPC) wind power converter in terms of operating and loading...... conditions are analytically solved and simulated. It has been found that the operating and loading conditions of the converter under LVRT strongly depend on the types/severity values of grid voltage dips and also the chosen control algorithms. The thermal distribution among the three phases of the converter...

  14. Dose estimation for nuclear power plant 4 accident in Taiwan at Fukushima nuclear meltdown emission level.

    Tang, Mei-Ling; Tsuang, Ben-Jei; Kuo, Pei-Hsuan

    2016-05-01

    An advanced Gaussian trajectory dispersion model is used to evaluate the evacuation zone due to a nuclear meltdown at the Nuclear Power Plant 4 (NPP4) in Taiwan, with the same emission level as that occurred at Fukushima nuclear meltdown (FNM) in 2011. Our study demonstrates that a FNM emission level would pollute 9% of the island's land area with annual effective dose ≥50 mSv using the meteorological data on 11 March 2011 in Taiwan. This high dose area is also called permanent evacuation zone (denoted as PEZ). The PEZ as well as the emergency-planning zone (EPZ) are found to be sensitive to meteorological conditions on the event. In a sunny day under the dominated NE wind conditions, the EPZ can be as far as 100 km with the first 7-day dose ≥20 mSv. Three hundred sixty-five daily events using the meteorological data from 11 March 2011 to 9 March 2012 are evaluated. It is found that the mean land area of Taiwan in becoming the PEZ is 11%. Especially, the probabilities of the northern counties/cities (Keelung, New Taipei, Taipei, Taoyuan, Hsinchu City, Hsinchu County and Ilan County) to be PEZs are high, ranging from 15% in Ilan County to 51% in Keelung City. Note that the total population of the above cities/counties is as high as 10 million people. Moreover, the western valleys of the Central Mountain Range are also found to be probable being PEZs, where all of the reservoirs in western Taiwan are located. For example, the probability can be as high as 3% in the far southern-most tip of Taiwan Island in Pingtung County. This shows that the entire populations in western Taiwan can be at risk due to the shortage of clean water sources under an event at FNM emission level, especially during the NE monsoon period. PMID:26913979

  15. Operation and thermal loading of three-level Neutral-Point-Clamped wind power converter under various grid faults

    Ma, Ke; Blaabjerg, Frede; Liserre, Marco

    In order to fulfill the continuous growing grid-side demands, the full-scale power converters are becoming more and more popular in the wind power application. Nevertheless, the more severe loading of the power semiconductor devices in the full-scale power converters, especially during Low Voltage...... Ride Through (LVRT) operation under grid faults, may compromise the reliability of the system and consequently further increase its cost. In this paper, the impact of various grid faults on a three-level Neutral-Point-Clamped (3L-NPC) grid-converter in terms of thermal loading of power semiconductor...... devices is highlighted. It has been found that the thermal loading of the phases of the power converter may be uneven and dependent on the different types and severities of grid voltage dips as well as on the chosen control algorithms....

  16. Probabilistic Safety Assessment (PSA) Level 1 Seismic Condition for AP600 Power Reactor

    Research about probabilistic safety assessment level 1 for AP600 power reactor has been conducted an seismic condition as external initiator. They key elements of this research are seismic fragility evaluation to define fragility curve of component s, accident sequence analysis to build event tree and fault tree, and core damage frequency as the final result. The seismic hazard analysis products a seismic occurrence per year for a certain range of seismic acceleration on a certain location. With large break LOCA as an addition fault condition 10 components and systems of AP600 have been chosen whose fragility curves can be made. Those are reactor coolant system piping. reactor protection system, reactor coolant pump, core makeup tank, accumulator tank, RWST, DC distribution panel cable trays, check valve, and isolation valve. The fragility curve shows in conditional fault probability on a seismic condition in form of normal cumulative distribution function with different confidences. This function is integrated from median acceleration Am, uncertainty βu and randomness βr parameter. From function and response analysis of AP600 systems a specific event tree and fault tree for large break LOCA are built with the fault probability parameter from the fragility curves as the input. The conditional probability of core damage can therefore be calculated for each accident sequence. After combined with values of the seismic hazard curve the core damage frequency per year for for each accident sequence and totally are obtained. The final calculation shows that the total core damage frequency for AP600 power reactor on seismic condition with the initiated fault condition large break LOCA is 3,87.10-7/years

  17. Transmural heterogeneity of cellular level power output is reduced in human heart failure

    Haynes, Premi; Nava, Kristofer E.; Lawson, Benjamin A.; Chung, Charles S.; Mitov, Mihail I.; Campbell, Stuart G.; Stromberg, Arnold J.; Sadayappan, Sakthivel; Bonnell, Mark R.; Hoopes, Charles W.; Campbell, Kenneth S.

    2014-01-01

    Heart failure is associated with pump dysfunction and remodeling but it is not yet known if the condition affects different transmural regions of the heart in the same way. We tested the hypotheses that the left ventricles of non-failing human hearts exhibit transmural heterogeneity of cellular level contractile properties, and that heart failure produces transmural region-specific changes in contractile function. Permeabilized samples were prepared from the sub-epicardial, mid-myocardial, and sub-endocardial regions of the left ventricular free wall of non-failing (n=6) and failing (n=10) human hearts. Power, an in vitro index of systolic function, was higher in non-failing mid-myocardial samples (0.59±0.06 μW mg−1) than in samples from the sub-epicardium (p=0.021) and the sub-endocardium (p=0.015). Non-failing mid-myocardial samples also produced more isometric force (14.3±1.33 kN m−2) than samples from the sub-epicardium (p=0.008) and the sub-endocardium (p=0.026). Heart failure reduced power (p=0.009) and force (p=0.042) but affected the mid-myocardium more than the other transmural regions. Fibrosis increased with heart failure (p=0.021) and mid-myocardial tissue from failing hearts contained more collagen than matched sub-epicardial (p<0.001) and sub-endocardial (p=0.043) samples. Power output was correlated with the relative content of actin and troponin I, and was also statistically linked to the relative content and phosphorylation of desmin and myosin light chain- 1. Non-failing human hearts exhibit transmural heterogeneity of contractile properties. In failing organs, region-specific fibrosis produces the greatest contractile deficits in the mid-myocardium. Targeting fibrosis and sarcomeric proteins in the mid-myocardium may be particularly effective therapies for heart failure. PMID:24560668

  18. The Level of Power Quality Measurement and Evaluation in A Stone Crusher Plant

    ŞEKKELİ, Mustafa; A.Serdar YILMAZ

    2009-01-01

    Both electric utilities and end users of electric power are becoming increasingly concerned about the quality of electric power. Quality of electrical energy in the electrical system that is requested continuous power (uninterrupted power), constant frequency and with constant amplitude can be explained by sinusoidal voltage. Deformation of voltage in the form of sinusoidal waveform is explained as a harmonic. Harmonics are most important factors in decreasing quality of energy in the electri...

  19. An Artificial Neural Network Compensated Output Feedback Power-Level Control for Modular High Temperature Gas-Cooled Reactors

    Zhe Dong

    2014-02-01

    Full Text Available Small modular reactors (SMRs could be beneficial in providing electricity power safely and also be viable for applications such as seawater desalination and heat production. Due to its inherent safety features, the modular high temperature gas-cooled reactor (MHTGR has been seen as one of the best candidates for building SMR-based nuclear power plants. Since the MHTGR dynamics display high nonlinearity and parameter uncertainty, it is necessary to develop a nonlinear adaptive power-level control law which is not only beneficial to the safe, stable, efficient and autonomous operation of the MHTGR, but also easy to implement practically. In this paper, based on the concept of shifted-ectropy and the physically-based control design approach, it is proved theoretically that the simple proportional-differential (PD output-feedback power-level control can provide asymptotic closed-loop stability. Then, based on the strong approximation capability of the multi-layer perceptron (MLP artificial neural network (ANN, a compensator is established to suppress the negative influence caused by system parameter uncertainty. It is also proved that the MLP-compensated PD power-level control law constituted by an experientially-tuned PD regulator and this MLP-based compensator can guarantee bounded closed-loop stability. Numerical simulation results not only verify the theoretical results, but also illustrate the high performance of this MLP-compensated PD power-level controller in suppressing the oscillation of process variables caused by system parameter uncertainty.

  20. Power Flow Control through a Multi-Level H-Bridge-based Power Converter for Universal and Flexible Power Management in Future Electrical Grids

    Iov, Florin; Bifaretti, Steffano; Zanchetta, Pericle;

    2008-01-01

    The paper proposes a novel power conversion system for Universal and Flexible Power Management (UNIFLEX-PM) in Future Electricity Network. The structure is based on three AC-DC converters each one connected to a different grid, (representing the main grid and/or various distributed generation...

  1. Three-phase three-level grid interactive inverter with fuzzy logic based maximum power point tracking controller

    Highlights: ► We propose a three phase three-level NPC inverter for grid interactive PV systems. ► We design fuzzy logic based maximum power point tracking algorithm. ► The proposed algorithm is robust with respect to parameter variations of PV system. ► THD level of the inverter current is in the limits of international standards. ► Total system efficiency is measured as 93.12%. - Abstract: In this study, three-phase single stage grid interactive inverter with maximum power point tracking capability is proposed. The proposed system consists of three-level neutral point clamped inverter, LCL output filter, line frequency transformer, PI current regulator and fuzzy logic based maximum power point tracking algorithm. Rate of change of photovoltaic power and voltage are defined as input variables, and the change in reference current is defined as output variable for the fuzzy logic controller. The proposed maximum power point tracking algorithm is robust with respect to parameter variations of photovoltaic system with adaptive feature of fuzzy logic controller. Maximum power point tracking algorithm determines the inverter current reference depending on the system conditions such as irradiation level and temperature, and PI regulator shapes the inverter output current. Two capacitors’ voltages of neutral point clamped inverter are also balanced. Simulation and experimental results show that the proposed inverter system has fast transient response and can track the maximum power point of PV system even if atmospheric condition changes rapidly. Also, the inverter output current is in sinusoidal waveform and in phase with line frequency and phase. In addition, total harmonic distortion level of the inverter output current is in the limits of international standards (<5%) and efficiencies of maximum power point tracking algorithm and total system are measured as 98.78% and 93.12%, respectively

  2. Costs of reducing water use of concentrating solar power to sustainable levels: Scenarios for North Africa

    Concentrating solar power (CSP) has the potential to become a leading sustainable energy technology for the European electricity system. In order to reach a substantial share in the energy mix, European investment in CSP appears most profitable in North Africa, where solar potential is significantly higher than in southern Europe. As well as sufficient solar irradiance, however, the majority of today's CSP plants also require a considerable amount of water, primarily for cooling purposes. In this paper we examine water usage associated with CSP in North Africa, and the cost penalties associated with technologies that could reduce those needs. We inspect four representative sites to compare the ecological and economical drawbacks from conventional and alternative cooling systems, depending on the local environment, and including an outlook with climate change to the mid-century. Scaling our results up to a regional level indicates that the use of wet cooling technologies would likely be unsustainable. Dry cooling systems, as well as sourcing of alternative water supplies, would allow for sustainable operation. Their cost penalty would be minor compared to the variance in CSP costs due to different average solar irradiance values. - Highlights: → Scaling up CSP with wet cooling from ground water will be unsustainable in North Africa. → Desalination and alternative cooling systems can assure a sustainable water supply. → On large-scale, the cost penalties of alternative cooling technologies appear minor.

  3. MONSTROUS HAZARDS PRODUCED BY HIGH RADIOACTIVITY LEVELS AROUND ASSIUT THERMAL POWER PLANT

    Hany El-Gamal

    2013-01-01

    Full Text Available The natural radioactivity level of heavy oil, ash and soil samples around Assiut Thermal Power Plant (ATPP in Egypt was determined using gamma ray spectrometry. The average concentrations of 226Ra, 232Th and 40K in fly ash were found to be 2307±143, 1281±80 and 1218±129 Bq kg-1, respectively, while the corresponding values in soil samples were 2670±107, 1401±78 and 1495±100 Bq kg-1, respectively. These are extremely high and higher by several orders of magnitude than the worldwide population-weighted average values in soil. The radium equivalent activity, the air absorbed dose rate, external hazard index and the annual effective dose rate were calculated and compared with the international recommended values. All averages of these parameters are much higher by several orders of magnitude than the international recommended values, indicating significant radiological health hazards around ATPP due to the radionuclides in the soil. Moreover, the water samples investigated have high activity concentrations indicating that the water is highly contaminated with radioactive materials. The results of the current study highlight the severity of this radioactive pollution on the population in the vicinity of ATPP.

  4. 129I level in seawater near a nuclear power plant determined by accelerator mass spectrometer

    129I concentration in the seawater samples near a nuclear power plant was determined in the Xi'an Accelerator Mass Spectrometer (AMS) Center. Isotope dilution method was used via addition of excessive amount of stable iodine (127I) in the sample before separation, and iodine in the seawater was separated by solvent extraction, and the back extracted iodine in iodide form was precipitated as AgI, which was used as AMS target for 129I measurement. 125I tracer was added to monitor the recovery of iodine in the whole separation process. 129I/127I ratios in the prepared target were determined by AMS. The concentration of 127I in seawater samples was determined by inductively coupled plasma mass spectrometry. The results show that the 129I/127I atomic ratios in the seawater range from 8.29x10-11 to 9.45x10-10, approximately one order of magnitude higher than that in seaweed collected in the pre-nuclear era, but fall in the environmental level of global fallout.

  5. A hybrid multi-level switching converter for ring-magnet power supplies

    Resonant networks in conjunction with dc-bias power supplies or phase-controlled rectifiers form the power supply systems for accelerator magnets. Although these power supplies, termed Ring-Magnet Power Supplies (RMPS), satisfy the steady-state performance criteria, they suffer from certain drawbacks. Conventionally, Ring-Magnet Power Supplies (RMPS) are designed using phase-controlled rectifiers or resonant networks with dc-bias power supplies. These power supply configurations satisfy the steady-state performance criteria for using large reactive components in addition to the magnet load. They have limited dynamic response, and often rely on corrector-magnet power supplies or other auxiliary power supply networks for the fast dynamic compensation required for output regulation and reference tracking. This paper proposes a Hybrid Multilevel Switching Converter as a RMPS which has fast dynamic response and meets the stringent output ripple content specifications. The proposed ring-magnet power supply also has the advantage of current waveshape programmability. The operating features of the hybrid multilevel switching converter has been described. The development of the RMPS with the hybrid multilevel switching converter as an unit has been explained. The current programmability of the proposed power supply configuration has been illustrated with computer simulations. Experimental results to substantiate the computer simulations are presented

  6. Compact high-power tunable three-level operation of double cladding Nd-doped fiber laser

    Fu, L. B.; Ibsen, M; Richardson, D J; Nilsson, J.; Payne, D. N.; Grudinin, A. B.

    2005-01-01

    We present a compact high-power continuous-wave tunable neodymium-doped double cladding fiber laser operating on three-level 4F3/2 - 4I9/2 transition with a maximum output power up to 810 mW. At 926.7 nm, it has a maximum slope efficiency of 49.3% against absorbed 808-nm pump. By compressing the fiber Bragg grating, 15-nm tuning range is achieved.

  7. Development of a Tool for Windfarm Site Analysis in Electrical Networks with High Levels of Wind Power Generation

    Carroll, Edward; McGrory, John

    2010-01-01

    Controlling electrical networks that contain high levels of wind power will be a challenge facing many System Operators in the coming years. The intermittency and uncertainty of the power supplied by wind turbines create difficulties surrounding scheduling of plant, operating reserve and grid integration. The current process for windfarm selection is carried out by an individual stakeholder and lacks the consideration for all other stakeholders involved, which can create problems in the long ...

  8. Potential impact of low-level radioactive effluents from Chongqing Fuling nuclear power plant to the Three Gorges Reservoir area

    Based on the radioactive source term of Chongqing Fuling Nuclear Power Plant in normal operating conditions, the hydrological data of Three Gorges Reservoir area nearby the site, and the aquatic environmental model calculations of radionuclide distribution from low-level radioactive waste, the radiation effects from liquid radioactive effluents to aquatic organisms in the Three Gorges Reservoir area were assessed with ERICA model, the impact to drinking water of downstream residents and agricultural production of coastal areas were analyzed. The results are as follows: (1) There will be no unacceptable impacts on aquatic organism in population and individuals levels from low-level radioactive liquid effluents of Chongqing Fuling Nuclear Power Plant; (2) There will be no adverse affect on the safety of drinking water of downstream residents; (3) There will be no adverse affect on agricultural irrigation from Chongqing Fuling Nuclear power plant on the nearest area including Fuling District, Fengdu County and other coastal areas of the Three Gorges Reservoir. (authors)

  9. Statistical properties of radiation power levels from a high-gain free-electron laser at and beyond saturation

    We investigate the statistical properties (e.g., shot-to-shot power fluctuations) of the radiation from a high-gain free-electron laser (FEL) operating in the nonlinear regime. We consider the case of an FEL amplifier reaching saturation whose shot-to-shot fluctuations in input radiation power follow a gamma distribution. We analyze the corresponding output power fluctuations at and beyond first saturation, including beam energy spread effects, and find that there are well-characterized values of undulator length for which the fluctuation level reaches a minimum

  10. An advanced static var compensator based on a three level IGBT inverter modelling analysis and active power filtering

    Draou, Azeddine

    2012-12-01

    This paper presents the dynamic performance analysis of an Advanced Static Var Compensator (ASVC) using three-level neutral point-clamped voltage source inverter. The paper presents the principles of operating and the method of reference currents generation. The dynamic behaviour of the system is further analysed using Matlab/Simulink with SimPower Systems toolbox through a set of simulation tests. The results obtained have been applied to an active power filter which might lead to the design of a robust controller for current harmonics and reactive power applications

  11. Nonlinear femtosecond pulse compression at high average power levels by use of a large-mode-area holey fiber.

    Südmeyer, T; Brunner, F; Innerhofer, E; Paschotta, R; Furusawa, K; Baggett, J C; Monro, T M; Richardson, D J; Keller, U

    2003-10-15

    We demonstrate that nonlinear fiber compression is possible at unprecedented average power levels by use of a large-mode-area holey (microstructured) fiber and a passively mode-locked thin disk Yb:YAG laser operating at 1030 nm. We broaden the optical spectrum of the 810-fs pump pulses by nonlinear propagation in the fiber and remove the resultant chirp with a dispersive prism pair to achieve 18 W of average power in 33-fs pulses with a peak power of 12 MW and a repetition rate of 34 MHz. The output beam is nearly diffraction limited and is linearly polarized. PMID:14587786

  12. Assessment of two-level heat pump installations’ power efficiency for heat supply systems

    Аlla Е. Denysova; Igor O. Bodnar

    2015-01-01

    The problem of energy saving becomes one of the most important in power engineering. It is caused by exhaustion of world reserves in hydrocarbon fuel, such as gas, oil and coal representing sources of traditional heat supply. Conventional sources has essential shortcomings: low power, ecological and economic efficiencies, that can be eliminated by using alternative methods of power supply, like the considered one: low-temperature natural heat of ground waters of on the basis of heat pump in...

  13. Teaching about energy use at the university level as a way to discuss nuclear power

    Alberta is considering getting a nuclear power plant. University science departments can play a significant role in educating the public about various aspects of nuclear power, and electricity usage in general. This paper discusses a novel class on energy production, use and distribution. This large lecture course has 100 students who have little to no technical training in energy. By teaching about energy issues, students become more interested nuclear power as part of the energy production portfolio. (author)

  14. On increasing the level of engineering and economical substatiation for wind power plants

    Basic arguments for developing wind power plants contained in the article by L.G.Ovis published in the journal Ehnergeticheskoe Mashinostroenie, N6, 1992 are analyzed. Incorrectness of the author's conclusion on advisability of using wind power plants in The Khabarovsk Region is proved. The conclusion on the necessity of fundamental technical-economical studies for substantiation of the wind power plant applicability in each individual case is made

  15. A Comprehensive Investigation on the Short Circuit Performance of MW-level IGBT Power Modules

    Wu, Rui; Reigosa, Paula Diaz; Iannuzzo, Francesco;

    2015-01-01

    This paper investigates the short circuit performance of commercial 1.7 kV / 1 kA IGBT power modules by means of a 6 kA Non-Destructive-Tester. A mismatched current distribution among the parallel chips has been observed, which can reduce the short circuit capability of the IGBT power module under...

  16. Coherent Power Analysis in Multi-Level Studies Using Design Parameters from Surveys

    Rhoads, Christopher

    2016-01-01

    Current practice for conducting power analyses in hierarchical trials using survey based ICC and effect size estimates may be misestimating power because ICCs are not being adjusted to account for treatment effect heterogeneity. Results presented in Table 1 show that the necessary adjustments can be quite large or quite small. Furthermore, power…

  17. Influence of power level and fuel type on safety and economy of the simplified pebble bed HTR concept

    For three different power levels, 20, 40 and 150 MWth, the PAP-HTR has been studied. This is an HTR Module concept that has been simplified in such a way that the continuously defuelling system has been eliminated and no defuelling takes place during a period of several years. Two core heatup scenarios have been simulated. It has been shown that in all cases the maximum fuel pebble temperature remains below 1600C, the temperature above which fuel degradation would start to occur, also after the reactor has gone critical again and the power level has been stabilized by itself. Fuel and gas temperature distributions are compared as well. The maximum pebble temperature before recriticality is higher for the loss of coolant (LOCA) scenario than for the loss of flow (LOFA) case, but the equilibrium maximum temperature after recriticality turns out to be higher for the pressurized case, because of the higher equilibrium power level. The equilibrium power level is a much smaller fraction of the nominal power level for the large 150 MWth system than for the smaller systems, due to the lower rate of cooling down of the large system after initiation of the accident. Therefore the equilibrium maximum temperature stays within acceptable limits for the large system too. The effects of the use of thorium fuel on the core height and waste radiotoxicity have been compared with the case of uranium fuel. Although it is widely believed that burnt thorium fuel would be cleaner than spent uranium fuel in terms of radiotoxicity, this did not appear to be more pronounced for this reactor concept than for e.g. PWRs. The relationship of power level and energy price is obvious for this power range. The use of thorium with highly enriched uranium could bring an additional economical advantage because of the lower core height needed for the same power level as the uranium case. With thorium a higher burnup can be attained, through which fuel pebbles can be added at a slower rate. The size of

  18. Use of Three-Level Power Converters in Wind-Driven Permanent-Magnet Synchronous Generators with Unbalanced Loads

    Ming-Hung Chen

    2015-06-01

    Full Text Available This paper describes the design and implementation of three-level power converters for wind-driven permanent-magnet synchronous generators with unbalanced loads. To increase voltage stress and reduce current harmonics in the electrical power generated by a wind generator, a three-phase, three-level rectifier is used. Because a synchronous rotating frame is used on the AC-input side, the use of a neutral-point-clamped controller is proposed to increase the power factor to unity and reduce current harmonics. Furthermore, a novel six-leg inverter is proposed for transferring energy from the DC voltage to a three-phase, four-wire AC source with a constant voltage and a constant frequency. The power converters also contain output transformers and filters for power buffering and filtering, respectively. All three output phase voltages are fed back to control the inverter output during load variations. A digital signal processor is used as the core control device for implementing a 1.5 kV, 75 kW drive system. Experimental data show that the power factor is successfully increased to unity and the total current harmonic distortion is 3.2% on the AC-input side. The entire system can attain an efficiency of 91%, and the voltage error between the upper and lower capacitors is approximately zero. Experimental results that confirm the high performance of the proposed system are presented.

  19. Long pulse H- beam extraction with a rf driven ion source on a high power level

    IPP Garching is investigating the applicability of rf driven negative ion sources for the neutral beam injection of International Thermonuclear Experimental Reactor. The setup of the tested source was improved to enable long pulses up to 100 kW rf power. The efficiency of negative ion production decreases at high power. The extracted H- currents as well as the symmetry of the plasma density close to the plasma grid and of the beam divergence depend on the magnetic filter field. The pulse duration is limited by the increase in coextracted electrons, which depends on the rf power and the caesium conditions on the plasma grid.

  20. Power

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2016-01-01

    In this chapter, we will explore the dynamics of power in processes of creativity, and show its paradoxical nature as both a bridge and a barrier to creativity in organisations. Recent social psychological experimental research (Slighte, de Dreu & Nijstad, 2011) on the relation between power and...... creativity suggests that when managers give people the opportunity to gain power and explicate that there is reason to be more creative, people will show a boost in creative behaviour. Moreover, this process works best in unstable power hierarchies, which implies that power is treated as a negotiable and...... floating source for empowering people in the organisation. We will explore and discuss here the potentials, challenges and pitfalls of power in relation to creativity in the life of organisations today. The aim is to demonstrate that power struggles may be utilised as constructive sources of creativity. It...

  1. A survey of low-level radioactive waste treatment methods and problem areas associated with commercial nuclear power plants

    A survey was made (June 1985) of technologies that were currently being used, those that had been discontinued, and those that were under consideration for treatment of low-level radioactive waste from the commercial nuclear power plants in the United States. The survey results included information concerning problems areas, areas needing research and development, and the use of mobile treatment facilities

  2. Development of Ribbon Fiber Type Multi-Channel Power Level Monitor with Low-Insertion/Polarization Loss

    Maki Inai; Akira Haraguchi; Takeo Komiya; Kiyotaka Murashima; Takashi Sasaki; Kazuhito Saitoh

    2003-01-01

    We would like to propose a new in-line multi-channel power level monitor, which is applicable as tap-monitor for multi-channel WDM signals. Its ribbon fiber structure has far exceeded PLC performance and realized compact-size and lower insertion/polarization dependent loss.

  3. Effect of Auricular Acupuncture with Low Power Laser on Four Chronic Allergic Dermatoses and Serum IgE Level

    You-hong Hou; Fang Xu; Shao-xi Wu

    2005-01-01

    @@ The objective of the study was to investigate the effectiveness of low power laser irradiating auricular points on four chronic allergic dermatoses including eczema, urticaria, facial cosmetic dermatitis, and atopic dermatitis, and on the changes of serum IgE level.

  4. Manpower development for each level of nuclear power plant personnel, experience and problems

    The following topics to be covered in this report are: Power plant organization and staff categories; basic education and training; practical experience requirements; effects of promotion and fluctuation; social problems associated with training abroad; technical problems and solutions. (orig.)

  5. Impact of a wave farm on its local grid: Voltage limits, flicker level and power fluctuations

    Blavette, Anne; O 'sullivan, Dara; Lewis, Antony; Egan, Michael

    2012-01-01

    Significant electrical power fluctuations in the range of seconds may be generated by most oscillating wave energy converters without significant amounts of energy storage capacity. Because of these fluctuations, a wave farm may have a negative impact on the power quality of the local grid to which it is connected. Hence, the impact of these devices on both distribution and transmission networks needs to be well understood, before large scale wave farms can be allowed to connect to the grid. ...

  6. Can we predict top-level sports performance in power vs endurance events? A genetic approach

    Buxens, Amaya; Ruiz, Jonatan R.; Arteta, David; Artieda, Marta; Santiago Dorrego, Catalina; González-Freire, Marta; Martínez, A.; Tejedor, Diego; Lao, José I.; Gómez Gallego, Félix; Lucía Mulas, Alejandro

    2011-01-01

    The goal of our study was to discriminate potential genetic differences between humans who are in both endpoints of the sports performance continuum (i.e. world-class endurance vs power athletes). We used DNA-microarray technology that included 36 genetic variants (within 20 different genes) to compare the genetic profile obtained in two cohorts of world-class endurance (N=100) and power male athletes (N=53) of the same ethnic origin. Stepwise multivariate logistic regression showed that the ...

  7. A Comprehensive Investigation on the Short Circuit Performance of MW-level IGBT Power Modules

    Wu, Rui; Reigosa, Paula Diaz; Iannuzzo, Francesco; Wang, Huai; Blaabjerg, Frede

    2015-01-01

    This paper investigates the short circuit performance of commercial 1.7 kV / 1 kA IGBT power modules by means of a 6 kA Non-Destructive-Tester. A mismatched current distribution among the parallel chips has been observed, which can reduce the short circuit capability of the IGBT power module under short circuit conditions. Further Spice simulations reveal that the stray parameters inside the module play an important role in contributing to such a phenomenon.

  8. Population-level scaling of avian migration speed with body size and migration distance for powered fliers.

    La Sorte, Frank A; Fink, Daniel; Hochachka, Wesley M; DeLong, John P; Kelling, Steve

    2013-08-01

    Optimal migration theory suggests specific scaling relationships between body size and migration speed for individual birds based on the minimization of time, energy, and risk. Here we test if the quantitative predictions originating from this theory can be detected when migration decisions are integrated across individuals. We estimated population-level migration trajectories and daily migration speeds for the combined period 2007-2011 using the eBird data set. We considered 102 North American bird species that use flapping or powered flight during migration. Many species, especially in eastern North America, had looped migration trajectories that traced a clockwise path with an eastward shift during autumn migration. Population-level migration speeds decelerated rapidly going into the breeding season, and accelerated more slowly during the transition to autumn migration. In accordance with time minimization predictions, spring migration speeds were faster than autumn migration speeds. In agreement with optimality predictions, migration speeds of powered flyers scaled negatively with body mass similarly during spring and autumn migration. Powered fliers with longer migration journeys also had faster migration speeds, a relationship that was more pronounced during spring migration. Our findings indicate that powered fliers employed a migration strategy that, when examined at the population level, was in compliance with optimality predictions. These results suggest that the integration of migration decisions across individuals does result in population-level patterns that agree with theoretical expectations developed at the individual level, indicating a role for optimal migration theory in describing the mechanisms underlying broadscale patterns of avian migration for species that use powered flight. PMID:24015527

  9. Enhancement in Power Quality With Grid Interconnection of Renewable Energy Sources at Distribution Level

    B.Yella Reddy

    2014-10-01

    Full Text Available At present the Renewable energy resources (RES are being increasingly connected in distribution systems utilizing power electronic converters. This paper presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as power converter to inject power generated from RES to the grid and shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies and validated through digital signal processor-based laboratory experimental results.

  10. Wearable Sensor System Powered by a Biofuel Cell for Detection of Lactate Levels in Sweat

    Garcia, S. O.; Ulyanova, Y. V.; Figueroa-Teran, R.; Bhatt, K. H.; Singhal, S.; Atanassov, P.

    2016-01-01

    An NAD+-dependent enzymatic sensor with biofuel cell power source system for non-invasive monitoring of lactate in sweat was designed, developed, and tested. The sensor component, based on lactate dehydrogenase, showed linear current response with increasing lactate concentrations with limits of detection from 5 to 100 mM lactate and sensitivity of 0.2 µA.mM−1 in the presence of target analyte. In addition to the sensor patch a power source was also designed, developed and tested. The power source was a biofuel cell designed to oxidize glucose via glucose oxidase. The biofuel cell showed excellent performance, achieving over 80 mA at 0.4 V (16 mW) in a footprint of 3.5 × 3.5 × 0.7 cm. Furthermore, in order to couple the sensor to the power source, system electronic components were designed and fabricated. These consisted of an energy harvester (EH) and a micropotentiostat (MP). The EH was employed for harvesting power provided by the biofuel cell as well as up-converting the voltage to 3.0 V needed for the operation of the MP. The sensor was attached to MP for chronoamperometric detection of lactate. The Sensor Patch System was demonstrated under laboratory conditions.

  11. Level of supply security provided by the German power plant fleet

    The security of Germany's electricity supply is a topic of intense debate. Although it could be discussed in quantitative terms, there has to date been no analytical study of this issue, or at least none reflected in the public debate. One possible measure of the security of supply of the German power plant fleet would be loss-of-load hours. This would have to be calculated by a central authority such as the Federal Network Agency. An estimate has shown that, assuming no other changes to the German power plant fleet, a phase-out of nuclear energy would lead to a substantial increase in annual loss-of-load hours.

  12. Deterministic and probabilistic methods to assess the safety level of operating nuclear power plants

    The German safety concept for nuclear power plants gives priority to the deterministic approach, i.e. deterministic analysis and good engineering judgement are primary tools of design evaluation. Probabilistic safety assessment is seen as a supplementary tool to the deterministic approach which provides quantitative information on the occurrence of incidents and thus can be used to check deterministic design assumptions, to evaluate desired plant and system modifications, to optimize backfitting measures and to quantify existing safety margins of operating nuclear power plants, e.g. in the frame of periodic safety reviews.(author)

  13. Unified System-Level Modeling of Intermittent Renewable Energy Sources and Energy Storage for Power System Operation

    Heussen, Kai; Koch, Stephan; Ulbig, Andreas;

    2011-01-01

    The system-level consideration of inter- mittent renewable energy sources and small-scale en- ergy storage in power systems remains a challenge as either type is incompatible with traditional operation concepts. Non-controllability and energy-constraints are still considered contingent cases in...... market-based operation. The design of operation strategies for up to 100 % renewable energy systems requires an explicit consideration of non-dispatchable generation and stor- age capacities, as well as the evaluation of operational performance in terms of energy eciency, reliability, environmental...... in power system operation. After introducing the modeling ap- proach, a case study is presented for illustration....

  14. Towards a Cellular Automata Based Network Intrusion Detection System with Power Level Metric in Wireless Adhoc Networks (IDFADNWCA)

    Sree, Pokkuluri Kiran; Babu, Inampudi Ramesh

    2014-01-01

    Adhoc wireless network with their changing topology and distributed nature are more prone to intruders. The efficiency of an Intrusion detection system in the case of an adhoc network is not only determined by its dynamicity in monitoring but also in its flexibility in utilizing the available power in each of its nodes. In this paper we propose a hybrid intrusion detection system, based on a power level metric for potential adhoc hosts, which is used to determine the duration for which a part...

  15. Drivers for the Value of Demand Response under Increased Levels of Wind and Solar Power; NREL (National Renewable Energy Laboratory)

    Hale, Elaine

    2015-07-30

    Demand response may be a valuable flexible resource for low-carbon electric power grids. However, there are as many types of possible demand response as there are ways to use electricity, making demand response difficult to study at scale in realistic settings. This talk reviews our state of knowledge regarding the potential value of demand response in several example systems as a function of increasing levels of wind and solar power, sometimes drawing on the analogy between demand response and storage. Overall, we find demand response to be promising, but its potential value is very system dependent. Furthermore, demand response, like storage, can easily saturate ancillary service markets.

  16. Megawatt-level peak-power from a passively Q-switched hybrid fiber-bulk amplifier and its applications

    Reiser, Axel; Bdzoch, Juraj; Höfer, Sven; Scholz-Riecke, Sina; Seitz, Daniel; Kugler, Nicolas; Genter, Peter

    2016-03-01

    A novel laser system with optical parameters that fill the gap between Q-switched and modelocked lasers has been developed. It consists of a high gain hybrid fiber-bulk amplifier seeded by a low power SESAM Q-switched oscillator. The mW level output power of the seed oscillator is preamplified by a single mode fiber which is limited by SRS effects. The final amplification stage is realized by a longitudinal pumped Nd:YVO4 crystal in a double pass setup. This MOPA configuration delivers sub-300ps pulses at repetition rates up to 1 MHz with an output power exceeding 60W. Nonlinear frequency conversion to 532nm and 355nm is achieved with efficiencies of >75% and >45%, respectively. Due to the high peak power, high repetition rate and high beam quality of this system, applications formerly only addressable at lower pulse repetition frequencies or with complex modelocked laser systems are now possible with high speed and lower cost of ownership. Application results that take benefit from these new laser parameters will be shown. Furthermore, the reduction of the pulse duration to sub-100ps and power scaling to output powers <100W by the use of the Innoslab concept are being presented.

  17. Low-power chip-level optical interconnects based on bulk-silicon single-chip photonic transceivers

    Kim, Gyungock; Park, Hyundai; Joo, Jiho; Jang, Ki-Seok; Kwack, Myung-Joon; Kim, Sanghoon; Kim, In Gyoo; Kim, Sun Ae; Oh, Jin Hyuk; Park, Jaegyu; Kim, Sanggi

    2016-03-01

    We present new scheme for chip-level photonic I/Os, based on monolithically integrated vertical photonic devices on bulk silicon, which increases the integration level of PICs to a complete photonic transceiver (TRx) including chip-level light source. A prototype of the single-chip photonic TRx based on a bulk silicon substrate demonstrated 20 Gb/s low power chip-level optical interconnects between fabricated chips, proving that this scheme can offer compact low-cost chip-level I/O solutions and have a significant impact on practical electronic-photonic integration in high performance computers (HPC), cpu-memory interface, 3D-IC, and LAN/SAN/data-center and network applications.

  18. An influence of occupational exposure on level of chromosome aberrations in nuclear power plant workers

    Complete text of publication follows. Objective. The workers of Ignalina Nuclear Power Plant (INPP) receive the highest occupational ionising radiation doses in Lithuania. Their occupational exposure results mainly from external low LET gamma radiation. Some workers receive additional internal and neutron exposure. Though exposure doses are generally low and don't exceed the annual dose limit, the higher doses are obtained during outages. The aim of the present study was to analyse chromosome aberration frequencies in lymphocytes of INPP workers exposed to the different types of ionising radiation. Methods. The blood sampling of 52 INPP male workers was performed in 2004-2006. For 29 workers radiation exposure resulted from the external gamma rays only. Their mean annual dose averaged over the 3-year period prior blood sampling was 11.7±8.7 mSv. The mean cumulative dose - 197.7±174.7 mSv. 15 workers had an intake of gamma radionuclides (60Co, 137Cs), contributing to the doses less than 0.1 mSv. Their mean cumulative dose - 278.2±191.9 mSv. The mean annual dose averaged over the 3-year period prior blood sampling was 11.8±5.3 mSv. For 8 subjects neutron doses below 0.2 mSv were recorded. Their mean annual dose averaged over the 3-year period prior blood sampling was 7.0±2.9 mSv. The mean cumulative dose was 241.8±93.0 mSv. Heparinized venous blood samples were taken and cultures were initiated according to the standard procedures. Phytohaemagglutinin (7.8 μg/ml) stimulated cultures were incubated at 37degC for 72 hours in RPMI 1640 medium supplemented with 12% heat-inactivated newborn calf serum, 40 μg/ml gentamycin. Colchicine was added to the culture during the initiation at a final concentration of 0,25 μg/ml. The harvested lymphocytes were treated with hypotonic KCl (0,075 M) and then fixed in methanol-glacial acetic acid (3:1). Flame-dried slides were stained with Giemsa, coded and scored blind. Generally 500 first-division cells per individual were

  19. Evaluation of SiC Power Diodes against Terrestrial Neutron-Induced Failure at Ground Level

    ASAI, HIROAKI; Sugimoto, Kenji; Nashiyama, Isamu; Shiba, Kensuke; Matsuda, Mieko; Morimura, Tadaaki

    2013-01-01

    Terrestrial neutrons cause single-event effects (SEEs) in semiconductor devices, which crucially affect the reliability of electronic systems used in the terrestrial environment. This paper presents evaluation results of high energy neutron-induced single-event burnout (SEB) in silicon carbide (SiC) power diodes and differences between SiC and silicon (Si) devices from the SEB standpoint.

  20. Teachers, School Boards, and the Power of Money: How the Right Wins at the Local Level

    Schirmer, Eleni B.; Apple, Michael W.

    2016-01-01

    This article examines national conservative political advocacy groups' growing interest in local politics, and analyzes how they form alliances and gain political power. Following efforts to restrict collective bargaining for Wisconsin public employees, Kenosha school board members' attempts to legally protect teachers' rights provoked concern…

  1. A methodology for Level 2 PSA evaluation with consideration of specific features for Low Power Shutdown Probabilistic Safety Assessment

    Kim, Jae Gab; Seok, Ho [KEPCO-ENC, Yongin (Korea, Republic of)

    2015-05-15

    The primary objective of the Level 2 PSA during Lower Power/Shutdown (LPSD) operation is to provide insights into potential plant vulnerabilities with regard to accident progression. The shutdown risk information can be used to provide the information to develop outage risk management guidelines. The LPSD Level 2 analysis utilizes much of the at-power Level 2 analysis for bounding, conservative treatment of severe accident phenomena. But, for some portions of the analysis including Plant Operational States (POSs), LPSD-specific evaluations such as UPC related to the containment Equipment Hatch (E/H) with 4 bolts, Reactor Coolant System (RCS) Not Intact for severe accident phenomena are desired for realistic evaluation. All POSs are evaluated for their Large Release Frequency (LRF). Some POSs are evaluated conservatively utilizing the at-power models, and other POSs are evaluated in specific analysis. The overall LPSD Level 2 model is evaluated. If the containment E/H and one of the two doors on each of the personal air locks are closed as containment is operable at reduced RCS inventory operation, LRF is expected to be less than 10% of LPSD CDF.

  2. A methodology for Level 2 PSA evaluation with consideration of specific features for Low Power Shutdown Probabilistic Safety Assessment

    The primary objective of the Level 2 PSA during Lower Power/Shutdown (LPSD) operation is to provide insights into potential plant vulnerabilities with regard to accident progression. The shutdown risk information can be used to provide the information to develop outage risk management guidelines. The LPSD Level 2 analysis utilizes much of the at-power Level 2 analysis for bounding, conservative treatment of severe accident phenomena. But, for some portions of the analysis including Plant Operational States (POSs), LPSD-specific evaluations such as UPC related to the containment Equipment Hatch (E/H) with 4 bolts, Reactor Coolant System (RCS) Not Intact for severe accident phenomena are desired for realistic evaluation. All POSs are evaluated for their Large Release Frequency (LRF). Some POSs are evaluated conservatively utilizing the at-power models, and other POSs are evaluated in specific analysis. The overall LPSD Level 2 model is evaluated. If the containment E/H and one of the two doors on each of the personal air locks are closed as containment is operable at reduced RCS inventory operation, LRF is expected to be less than 10% of LPSD CDF

  3. Multimodel-based power-level control with state-feedback and observer for load-follow PWR core

    Highlights: • The equilibrium manifold and nonlinearity measure of the core are proposed. • The linear multi-model of the core is built based on the core nonlinearity measure. • A new state feedback control is used to design local controllers of the core. • Flexibility partitioning of model and control is presented for the nonlinear core. • The global stability of the core load follow control is analyzed. - Abstract: The purpose of this investigation is that a nonlinear Pressurized Water Reactor (PWR) core load following control system is designed and the global stability of the system is analyzed theoretically. On the basis of modeling a nonlinear PWR core and proposing the equilibrium manifold and the nonlinearity measure of the core to calculate the distribution situation of the core nonlinearity measure in the entire range of power level, linearized models of the core at five power levels are chosen as local models of the core and the set of local models is used to substitute the nonlinear core model. The full-state feedback control with a full-order observer is utilized to design a controller with robustness of every local model, which is treated as a local controller of the nonlinear core. The Kalman filter is contrived as an observer with robustness and the state feedback design with robustness is implemented via the robust pole assignment method. With the local models and local controllers, the flexibility partitioning of model and control is presented to design a decent flexibility controller of the nonlinear core at a random power level. A nonlinear core model and a flexibility controller at a random power level compose a core load following control subsystem. The combination of core load following control subsystems at all power levels is the core load following control system. Two global stability theorems are deduced to define that the core load following control system is globally asymptotically stable within the whole range of power level

  4. Application-ready cement recipes for solidification of low and medium level radioactive wastes from nuclear power plants

    The R+D program for solidification of low and medium level wastes from Swiss power plants is carried out at EIR (Swiss Federal Institute for Reactor Research) under contract to Nagra (National Cooperative for the Storage of Radioactive Waste). Up to now, 7 practicable recipes for these waste types have been developed for use. With these recipes the main quantities of all possible reactor radwastes arising from operating Swiss power plants can be solidified with cements. The solidified matrixes then produced fulfill the conditions required by the Swiss regulatory authorities. As a first barrier, they contribute to a safe final storage of these wastes in geological formations in Switzerland. For new waste types arising, for 'special wastes', and for the wastes from power stations not yet commissioned, the R+D work is going on. Future results will probably allow further improvement of the recipes and processes already developed. (author)

  5. Megahertz-level, high-power picosecond Nd:LuVO4 regenerative amplifier free of period doubling.

    Gao, Peng; Lin, Hua; Li, Jinfeng; Guo, Jie; Yu, Haohai; Zhang, Huaijin; Liang, Xiaoyan

    2016-06-27

    We report on a high repetition rate, high-power picosecond Nd:LuVO4 regenerative amplifier. Period doubling caused energy instability was eliminated at megahertz-level repetition rate with the modified seeding source. A multi-pass cell was used to improve the seed pulse energy to achieve complete suppression of the onset of bifurcation. At a maximum repetition rate of 1.43 MHz, the system produced 7.0-ps-long pulses with an average output power of 25.1 W, corresponding to a pulse energy of 17.6 μJ. At 100 kHz, the pulse energy increased to 205 μJ with an average power of 20.5 W. Moreover, the injected pulses with pulse duration of 5.1 ps broadened to 8.9 ps because of gain narrowing in the amplifier. PMID:27410559

  6. A low-power and small-area column-level ADC for high frame-rate CMOS pixel sensor

    CMOS pixel sensors (CPS) have demonstrated performances meeting the specifications of the International Linear Collider (ILC) vertex detector (VTX). This paper presents a low-power and small-area 4-bit column-level analog-to-digital converter (ADC) for CMOS pixel sensors. The ADC employs a self-timed trigger and completes the conversion by performing a multi-bit/step approximation. As in the outer layers of the ILC vertex detector hit density is of the order of a few per thousand, in order to reduce power consumption, the ADC is designed to work in two modes: active mode and idle mode. The ADC is fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. It is implemented with 48 columns in a sensor prototype. Each column ADC covers an area of 35 ×545 μm2. The measured temporal noise and Fixed Pattern Noise (FPN) are 0.96 mV and 0.40 mV, respectively. The power consumption, for a 3 V supply and 6.25 MS/s sampling rate, is 486 μW during idle time, which is by far the most frequently employed one. This value rises to 714 μW in the case of the active mode. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.49/−0.28 LSB and 0.29/−0.20 LSB, respectively. - Highlights: • CMOS sensor integrated with column-level ADC is proposed for ILC VTX outer layers. • A low-power and small-area column-level ADC for high frame-rate CPS is presented. • The test results demonstrate the power and area efficiency. • The architecture is suitable for the outer layer CMOS sensors

  7. A low-power and small-area column-level ADC for high frame-rate CMOS pixel sensor

    Zhang, L., E-mail: liang.zhang@iphc.cnrs.fr [School of Physics, Key Laboratory of Particle Physics and Particle Irradiation, Shandong University, 250100 Jinan (China); Institut Pluridisciplinaire Hubert Curien, University of Strasbourg, CNRS/IN2P3/UDS, 23 rue du loess, BP 28, 67037 Strasbourg (France); Morel, F.; Hu-Guo, C.; Hu, Y. [Institut Pluridisciplinaire Hubert Curien, University of Strasbourg, CNRS/IN2P3/UDS, 23 rue du loess, BP 28, 67037 Strasbourg (France)

    2014-07-01

    CMOS pixel sensors (CPS) have demonstrated performances meeting the specifications of the International Linear Collider (ILC) vertex detector (VTX). This paper presents a low-power and small-area 4-bit column-level analog-to-digital converter (ADC) for CMOS pixel sensors. The ADC employs a self-timed trigger and completes the conversion by performing a multi-bit/step approximation. As in the outer layers of the ILC vertex detector hit density is of the order of a few per thousand, in order to reduce power consumption, the ADC is designed to work in two modes: active mode and idle mode. The ADC is fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. It is implemented with 48 columns in a sensor prototype. Each column ADC covers an area of 35 ×545 μm{sup 2}. The measured temporal noise and Fixed Pattern Noise (FPN) are 0.96 mV and 0.40 mV, respectively. The power consumption, for a 3 V supply and 6.25 MS/s sampling rate, is 486 μW during idle time, which is by far the most frequently employed one. This value rises to 714 μW in the case of the active mode. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.49/−0.28 LSB and 0.29/−0.20 LSB, respectively. - Highlights: • CMOS sensor integrated with column-level ADC is proposed for ILC VTX outer layers. • A low-power and small-area column-level ADC for high frame-rate CPS is presented. • The test results demonstrate the power and area efficiency. • The architecture is suitable for the outer layer CMOS sensors.

  8. Saturated Adaptive Output-Feedback Power-Level Control for Modular High Temperature Gas-Cooled Reactors

    Zhe Dong

    2014-11-01

    Full Text Available Small modular reactors (SMRs are those nuclear fission reactors with electrical output powers of less than 300 MWe. Due to its inherent safety features, the modular high temperature gas-cooled reactor (MHTGR has been seen as one of the best candidates for building SMR-based nuclear plants with high safety-level and economical competitive power. Power-level control is crucial in providing grid-appropriation for all types of SMRs. Usually, there exists nonlinearity, parameter uncertainty and control input saturation in the SMR-based plant dynamics. Motivated by this, a novel saturated adaptive output-feedback power-level control of the MHTGR is proposed in this paper. This newly-built control law has the virtues of having relatively neat form, of being strong adaptive to parameter uncertainty and of being able to compensate control input saturation, which are given by constructing Lyapunov functions based upon the shifted-ectropies of neutron kinetics and reactor thermal-hydraulics, giving an online tuning algorithm for the controller parameters and proposing a control input saturation compensator respectively. It is proved theoretically that input-to-state stability (ISS can be guaranteed for the corresponding closed-loop system. In order to verify the theoretical results, this new control strategy is then applied to the large-range power maneuvering control for the MHTGR of the HTR-PM plant. Numerical simulation results show not only the relationship between regulating performance and control input saturation bound but also the feasibility of applying this saturated adaptive control law practically.

  9. Photon pair generation from compact silicon microring resonators using microwatt-level pump powers

    Savanier, Marc; Mookherjea, Shayan

    2015-01-01

    Microring resonators made from silicon, using deep ultraviolet lithography fabrication processes which are scalable and cost-effective, are becoming a popular microscale device format for generating photon pairs at telecommunications wavelengths at room temperature. In compact devices with a footprint less than $5\\times 10^{-4}$ mm$^2$, we demonstrate pair generation using only a few microwatts of average pump power. We discuss the role played by important parameters such as the loss, group-velocity dispersion and the ring-waveguide coupling coefficient in finding the optimum operating point for silicon microring pair generation. Such small devices and low pump power requirements could be beneficial for future scaled-up architectures with many pair-generation devices on the same chip, which will be required to create quasi-deterministic pure single photon sources from inherently statistical processes such as spontaneous four-wave mixing.

  10. Photon pair generation from compact silicon microring resonators using microwatt-level pump powers.

    Savanier, Marc; Kumar, Ranjeet; Mookherjea, Shayan

    2016-02-22

    Microring resonators made from silicon are becoming a popular microscale device format for generating photon pairs at telecommunications wavelengths at room temperature. In compact devices with a footprint less than 5 × 10-4 mm2, we demonstrate pair generation using only a few microwatts of average pump power. We discuss the role played by important parameters such as the loss, group-velocity dispersion and the ring-waveguide coupling coefficient in finding the optimum operating point for silicon microring pair generation. Silicon photonics can be fabricated using deep ultraviolet lithography wafer-scale fabrication processes, which is scalable and cost-effective. Such small devices and low pump power requirements, and the side-coupled waveguide geometry which uses an integrated waveguide, could be beneficial for future scaled-up architectures where many pair-generation devices are required on the same chip. PMID:26906993

  11. Prediction of temperature and water level in a spent fuel pit during loss of all AC power supplies

    A prediction method for water temperature in a spent fuel pit of a pressurized water reactor (PWR) has been developed to calculate the increase in water temperature during the shutdown of cooling systems. In this study, the prediction method was extended to calculate the water level in a spent fuel pit during loss of all AC power supplies, and predicted results were compared with measured values of spent fuel pools in the Fukushima Daiichi Nuclear Power Station. The calculations gave reasonable results, but overestimated the decreasing rate of the water level and the water temperature. This indicated that decay heat was overestimated and evaporation heat transfer from the water surface was underestimated. Results of calculations with 80% decay heat and 155% (Unit 4 pool) or 230% (Unit 2 pool) evaporation heat flux were in good agreement with measured values. The data-fitted evaporation heat fluxes agreed rather well with the evaporation heat transfer correlation proposed by Fujii et al. (author)

  12. Prediction of temperature and water level in a spent fuel pit during loss of all AC powers

    A prediction method for water temperature in a spent fuel pit of a PWR has been developed to calculate the increase in water temperature during the shutdown of cooling systems. In this study, the prediction method was extended to calculate the water level in a spent fuel pit during loss of all AC powers, and predicted results were compared with data of spent fuel pools in the Fukushima Daiichi Nuclear Power Station. The calculations gave reasonable results, but overestimated the decreasing rate of the water level and water temperature. This result indicated that decay heat was overestimated and evaporation heat transfer from the water surface was underestimated. Results of calculations with 80% decay heat and 155% (No. 4 pool) or 230% (No. 2 pool) evaporation heat flux were in good agreement with data. The data-fitted evaporation heat fluxes agreed rather well with the evaporation heat transfer correlation proposed by Fujii et al. (author)

  13. The level of residual dispersion variation and the power of differential expression tests for RNA-Seq data.

    Gu Mi

    Full Text Available RNA-Sequencing (RNA-Seq has been widely adopted for quantifying gene expression changes in comparative transcriptome analysis. For detecting differentially expressed genes, a variety of statistical methods based on the negative binomial (NB distribution have been proposed. These methods differ in the ways they handle the NB nuisance parameters (i.e., the dispersion parameters associated with each gene to save power, such as by using a dispersion model to exploit an apparent relationship between the dispersion parameter and the NB mean. Presumably, dispersion models with fewer parameters will result in greater power if the models are correct, but will produce misleading conclusions if not. This paper investigates this power and robustness trade-off by assessing rates of identifying true differential expression using the various methods under realistic assumptions about NB dispersion parameters. Our results indicate that the relative performances of the different methods are closely related to the level of dispersion variation unexplained by the dispersion model. We propose a simple statistic to quantify the level of residual dispersion variation from a fitted dispersion model and show that the magnitude of this statistic gives hints about whether and how much we can gain statistical power by a dispersion-modeling approach.

  14. The level of residual dispersion variation and the power of differential expression tests for RNA-Seq data.

    Mi, Gu; Di, Yanming

    2015-01-01

    RNA-Sequencing (RNA-Seq) has been widely adopted for quantifying gene expression changes in comparative transcriptome analysis. For detecting differentially expressed genes, a variety of statistical methods based on the negative binomial (NB) distribution have been proposed. These methods differ in the ways they handle the NB nuisance parameters (i.e., the dispersion parameters associated with each gene) to save power, such as by using a dispersion model to exploit an apparent relationship between the dispersion parameter and the NB mean. Presumably, dispersion models with fewer parameters will result in greater power if the models are correct, but will produce misleading conclusions if not. This paper investigates this power and robustness trade-off by assessing rates of identifying true differential expression using the various methods under realistic assumptions about NB dispersion parameters. Our results indicate that the relative performances of the different methods are closely related to the level of dispersion variation unexplained by the dispersion model. We propose a simple statistic to quantify the level of residual dispersion variation from a fitted dispersion model and show that the magnitude of this statistic gives hints about whether and how much we can gain statistical power by a dispersion-modeling approach. PMID:25849826

  15. Market oriented and rational use of energy and power. Level of competence and need of skill

    This report surveys the existing research and development (R and D) skill in Norway in the field of ''Market oriented and rational use of energy and power''. The need for skills upgrading and future R and D is discussed. Four areas for R and D are identified as especially important: (1) external conditions, (2) end user behavior, (3) the interplay of all issues related to the end user's competence, and (4) information and communication technology

  16. SEB circuit-level model in N-channel power MOSFETs

    A Single Event Burnout (SEB) circuit model has been developed. The dependence of SEB sensitivity on various parameters is presented and compared with experimental results. The parasitic resistance and capacitance of the device as well as the circuit parameters contribute to the length of SEB pulse. Increasing the switching frequency of the power MOSFET may be a possible way to prevent SEB in applications. (authors)

  17. Environmental levels of carbon-14 around a Swedish nuclear power plant measured with accelerator mass spectrometry

    Stenström, K.; Erlandsson, B.; Hellborg, R.; Wiebert, A.; Skog, G.

    1996-06-01

    14C is one of the radionuclides which are produced by nuclear power plants. The main part of the 14C, which is released during normal operation, is produced through neutron induced reactions in the cooling water and is released as airborne effluents (such as CO 2 and hydrocarbons) through the ventilation system of the plant to the surrounding environment. Because of the biological importance of carbon and the long half-life of 14C, it is of interest to measure the releases and their incorporation into living material in the environment of the power plants. In this pilot study the accelerator mass spectrometry (AMS) facility at the University of Lund has been used to measure the 14C activity concentration in vegetation around a Swedish nuclear power plant. AMS is suitable mainly because of the accuracy obtained within a short measuring time, which makes it possible to analyze a sufficient number of samples for a thorough investigation. The results of this study demonstrate that the AMS method is suitable for investigations of the influence on the local environment of reactor-released 14C by analysis of living material. To test dispersion models, however, air sampling both of emission source and in the surrounding of the plant seems more suitable.

  18. Impact of the Power Sector Development on the Emission Level in Lithuania

    The analyses carried out show that further necessary investments into safety improvements of the Ignalina NPP satisfy the criterion of the least cost power sector development and it should be kept in operation until the end of its technical life time. Modular CHP with diesel engines or gas turbines, or new CCGT will be the most attractive source of electricity generation if new capacities are required. The Ignalina NPP also has crucial impact on all kind of emissions in Lithuania. If this power plant is shut down, the requirement of the Kyoto Protocol for CO2 mitigation will be violated already in 2011, even in the case of the most pessimistic economy growth and electricity export scenario. In the case of the further operation of the nuclear power plant Lithuania will be able to fulfil the requirement of the Kyoto Protocol during the whole study period. However, during temporary shut down of the nuclear plant for safety upgrade or rechannelling of reactors some reduction of electricity export will be necessary. (author)

  19. Is the level of financial sector development a key determinant of private investment in the power sector ?

    Gasmi, Farid; Lika, Ba; Noumba Um, Paul

    2010-01-01

    TThis paper seeks to assess the extent to which a country’s overall level of development and that of its financial sector, in particular, are factors that attract private capital into infrastructure projects. The authors investigate these effects in a 1990–2007 dataset on the power sector in 37 developing countries. The results suggest that economic growth is a key determinant of private investors’ investment in infrastructure projects, and that investors tend to take countries’ governance...

  20. Stand by Leakage Power Reduction in Nanoscale Static CMOS VLSI Multiplier Circuits Using Self Adjustable Voltage Level Circuit

    Deeprose Subedi; Eugene John

    2012-01-01

    In this paper, we performed the comparative analysis of stand-by leakage (when the circuit is idle), delay and dynamic power (when the circuit switches) of the three different parallel digital multiplier circuits implemented with two adder modules and Self Adjustable Voltage level circuit (SVL). The adder modules chosen were 28 transistor-conventional CMOS adder and 10 transistor- Static Energy Recovery CMOS adder (SERF) circuits. The multiplier modules chosen were 4Bits Array, 4 bits Carry S...

  1. Unified System-Level Modeling of Intermittent Renewable Energy Sources and Energy Storage for Power System Operation

    Heussen, Kai; Koch, Stephan; Ulbig, Andreas; Andersson, Goran

    2011-01-01

    The system-level consideration of inter- mittent renewable energy sources and small-scale en- ergy storage in power systems remains a challenge as either type is incompatible with traditional operation concepts. Non-controllability and energy-constraints are still considered contingent cases in market-based operation. The design of operation strategies for up to 100 % renewable energy systems requires an explicit consideration of non-dispatchable generation and stor- age capacities, as well a...

  2. Effect of Carbohydrate Solutions with Different level of Sugar on Average Anaerobic power and Fatigue index of karate Players

    AMINIAN, Ensiyeh

    2015-01-01

    Abstract. Main aim of this research was investigating effect of carbohydrate solutions with different level of sager on average anaerobic power and fatigue index of karate players. Statistical sample of this research was 72 karate players of Khorasa Razavi province and 48 people were selected randomly. Average age, weight, height, and BMI were measures Average age of athletes was 22.23, average height 175cm and average weight 72.77. We used frequency distribution tables and indexes of the cen...

  3. Methodology for the economic optimisation of energy storage systems for frequency support in wind power plants

    Highlights: • Optimisation of energy storage system with wind power plant for frequency response. • Energy storage option considered could be economically viable. • For a 50 MW wind farm, an energy storage system of 5.3 MW and 3 MW h was found. - Abstract: This paper proposes a methodology for the economic optimisation of the sizing of Energy Storage Systems (ESSs) whilst enhancing the participation of Wind Power Plants (WPP) in network primary frequency control support. The methodology was designed flexibly, so it can be applied to different energy markets and to include different ESS technologies. The methodology includes the formulation and solving of a Linear Programming (LP) problem. The methodology was applied to the particular case of a 50 MW WPP, equipped with a Vanadium Redox Flow battery (VRB) in the UK energy market. Analysis is performed considering real data on the UK regular energy market and the UK frequency response market. Data for wind power generation and energy storage costs are estimated from literature. Results suggest that, under certain assumptions, ESSs can be profitable for the operator of a WPP that is providing frequency response. The ESS provides power reserves such that the WPP can generate close to the maximum energy available. The solution of the optimisation problem establishes that an ESS with a power rating of 5.3 MW and energy capacity of about 3 MW h would be enough to provide such service whilst maximising the incomes for the WPP operator considering the regular and frequency regulation UK markets

  4. Mean sea level and change in the hydrological regime off Loviisa power plant around the year 2050

    On the request of Imatran Voima Oy, the Institute of Marine Research has made an estimate on the future sea level off Loviisa Power Plant. The estimate is based on observationsof mean sea level in the Gulf of Finland. The stations used are Helsinki (observations since 1904) and Hamina (observations since 1928). A litterature review was made in order to estimate impact of climate change on environmental conditions. The results presented are mainly based on various estimates of meterorological Global Circulation Models (GCM). Their usefulness in the connection is briefly discussed

  5. Power-Performance Trade-Offs in Nanometer-Scale Multi-Level Caches Considering Total Leakage

    Bai, Robert; Kgil, Tae Ho; Sylvester, Dennis; Mudge, Trevor

    2011-01-01

    In this paper, we investigate the impact of T_{ox} and Vth on power performance trade-offs for on-chip caches. We start by examining the optimization of the various components of a single level cache and then extend this to two level cache systems. In addition to leakage, our studies also account for the dynamic power expanded as a result of cache misses. Our results show that one can often reduce overall power by increasing the size of the L2 cache if we only allow one pair of Vth/T_{ox} in L2. However, if we allow the memory cells and the peripherals to have their own Vth's and T_{ox}'s, we show that a two-level cache system with smaller L2's will yield less total leakage. We further show that two Vth's and two T_{ox}'s are sufficient to get close to an optimal solution, and that Vth is generally a better design knob than T_{ox} for leakage optimization, thus it is better to restrict the number of T_{ox}'s rather than Vth's if cost is a concern.

  6. Superradiance on the Landau levels and the problem of power of decameter radiation of Jupiter

    Fomin, P. I.; Fomina, A. P.; Malnev, V. N.

    2002-01-01

    We determine the conditions of formation of spontaneous polarization phase transition to the superradiance regime in the inverted system of nonrelativistic electrons on equidistant Landau levels in rarefied magnetized plasma. The possibility of realization of such conditions in the lower Jupiter magnetosphere is shown. The effect of cyclotron superradiance on the Landau levels gives a key to interpretation of the nature of superpower radioemission of the Jupiter-Io system.

  7. Physical activity level, musculoskeletal fitness,balance, strength and power performance in older adults

    Lohne-Seiler, Hilde

    2015-01-01

    The link between physical activity and prevention of disease, maintenance of independence, and improved quality of life in older adults is supported by strong evidence. However, there is a lack of data on population levels where physical activity level has been measured objectively in association with self-reported health, musculoskeletal fitness and balance variables in older men and women. Also, little is known about the functional adaptive responses of older adults to pow...

  8. Procedure for conducting probabilistic safety assessment: level 1 full power internal event analysis

    This report provides guidance on conducting a Level I PSA for internal events in NPPs, which is based on the method and procedure that was used in the PSA for the design of Korea Standard Nuclear Plants (KSNPs). Level I PSA is to delineate the accident sequences leading to core damage and to estimate their frequencies. It has been directly used for assessing and modifying the system safety and reliability as a key and base part of PSA. Also, Level I PSA provides insights into design weakness and into ways of preventing core damage, which in most cases is the precursor to accidents leading to major accidents. So Level I PSA has been used as the essential technical bases for risk-informed application in NPPs. The report consists six major procedural steps for Level I PSA; familiarization of plant, initiating event analysis, event tree analysis, system fault tree analysis, reliability data analysis, and accident sequence quantification. The report is intended to assist technical persons performing Level I PSA for NPPs. A particular aim is to promote a standardized framework, terminology and form of documentation for PSAs. On the other hand, this report would be useful for the managers or regulatory persons related to risk-informed regulation, and also for conducting PSA for other industries

  9. Modelling of the Multi-Level STATCOM for Harmonic Stability Studies in Offshore Wind Power Plants

    Glasdam, Jakob Bærholm; Bak, Claus Leth; Hjerrild, Jesper;

    2017-01-01

    -bridge converter based MMCC. Complex reconfiguration is required to extend the existing approach to the full-bridge converter. This paper presents a modelling techniqueof the full-bridge converter MMCC, which is easily scalable and provides simulation acceleration ratios similar to the previous model of the half......-bridge MMCC. A comparison with field measurement shows that the proposed model is highly capable to simulate the waveforms of a commercial MMCC, even when a generic controller is applied in the model. Presentedsimulation studiesshowthe occurance of harmonic instability in wind power plants and the application...

  10. Design of kW level picosecond compressor ofpump pulses for high power OPCPA

    Bakule, Pavel; Novák, Jakub; Kramer, Daniel; Strkula, Petr; Novák, Miroslav; Hřebíček, Jan; Koutris, E.; Zervos, Charalampos; Baše, Radek; Batysta, František; Hubka, Z.; Green, Jonathan T.; Rus, Bedřich

    Bellingham: SPIE, 2013 - (Hein, J.; Korn, G.; Silva, L.). (Proceedings of SPIE. 8780). ISBN 978-0-8194-9582-2. ISSN 0277-786X. [High-Power, High-Energy, and High-Intensity Laser Technology; and Research Using Extreme Light - Entering New Frontiers with Petawatt-Class Lasers. Praha (CZ), 15.04.2013-17.04.2013] R&D Projects: GA MŠk ED1.1.00/02.0061 Grant ostatní: ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061 Institutional support: RVO:68378271 Keywords : amplifiers * crystals * lasers * nonlinear crystals * second-harmonic generation Subject RIV: BH - Optics, Masers, Lasers

  11. Assessment of radioactive inventories and radiation levels for decommissioning of civil power reactors

    The paper presents an overview of the methodology used by NNC Ltd. for the determination of nuclear power station radioactive inventories, particularly of the neutron activated structures in and around the cores of reactors, at times relevant to decommissioning. It describes the computer programs used to calculate neutron flux distributions and the way that these are used to provide component averaged values for use in the inventory calculation. The nuclides of importance are discussed and an example is given of an inventory analysis performed for an advanced gas cooled reactor. This inventory is then used to compute decommissioning dose rates. (Author)

  12. Results of safety analysis concerning level gauge of pressurizer and related measures for Ohi Nuclear Power Station

    The results of safety analysis concerning the level gauge of a pressurizer and the related measures for the Ohi Nuclear Power Station, which were reported by the Ministry of International Trade and Industry on May 1, 1979, and then investigated and presented by the Nuclear Reactor Safety Special Investigation Committee, are regarded as appropriate by the Atomic Energy Safety Commission (AESC) on May 19, 1979. This analysis and investigation were conducted in relation to the accident in the Three Mile Island (TMI) No. 2 nuclear power plant, occurred on March 28, 1979. In this investigation the influences of the problem concerning the level gauge for a pressurizer of the Ohi Nuclear Power Station on the function and the performance of emergency core cooling system (ECCS) for pressurized water reactors were analyzed, simulating the initial phenomena of the accident in TMI. As for the adequacy of the prior conditions of safety analysis and the analytical codes, the following three points were investigated; 1) the adequacy of accident conditions which were set as the subjects of safety analysis, 2) the adequacy of the assumption supposing that the auxiliary feed water pump is started by manual operation fifteen minutes after accident occurrence, and 3) the adequacy of the analytical Codes MARVEL and SATAN-6. The analytical results showed that the relief valve on a pressurizer does not operate at the similar accident to TMI in the Ohi Nuclear Power Station, because the difference of design exists between both plants, and also even if the relief valve on a pressurizer operates and does not close, the core is cooled sufficiently in the Ohi Nuclear Power Station. (Nakai, Y.)

  13. The application of power-to-gas, pumped hydro storage and compressed air energy storage in an electricity system at different wind power penetration levels

    Many countries worldwide have committed themselves to reducing the rate in which they emit greenhouse gasses. These emissions are the major driver behind human induced global warming. Renewable electricity implementation is one way of reducing the amount of greenhouse gas emissions. However, this transition is also accompanied by some problems. The intermittency of renewables demands for a more flexible electricity system. In existing electricity systems this lack of flexibility already leads to load balancing issues increasing costs and threatening energy security. Large scale storage facilities could provide the needed flexibility. This paper focuses on the economic and environmental system consequences of the application of power-to-gas, pumped hydro storage and compressed air energy storage in an electricity system at different wind power penetration levels. The study shows that the application of large scale energy storage techniques results in economic costs reducing effects on the electricity system. These are highest for pumped hydro storage, followed by the cost reducing effects of compressed air energy storage and power-to-gas. The impact on the fuel use and the emissions is less obvious. In some scenarios, the application of storage even resulted in an increase of the fuel use and the emissions. - Highlights: • We studied the effects of adding three storage techniques to an electricity system. • We modelled: Power-to-gas, pumped hydro storage and compressed air energy storage. • Storage is used for optimizing the operational costs of the electricity system. • The economic system benefits were highest when applying pumped hydro storage. • The application of storage not always resulted in environmental system benefits

  14. Design of kW level picosecond compressor of pump pulses for high power OPCPA

    Bakule, Pavel; Novák, Jakub; Kramer, Daniel; Strkula, Petr; Novák, Miroslav; Hřebíček, Jan; Koutris, Efstratios; Zervos, Charalampos; Baše, Radek; Batysta, František; Hubka, Zbyněk.; Green, Jonathan T.; Rus, Bedřich

    2013-05-01

    We present a design of a high average power vacuum compressor unit for 1 kHz repetition rate pump laser operating at 1030 nm. The unit comprises two compressors and two SHG units located in a common vacuum vessel. Both compressors are designed with GDD of -270.5 ps2 for compressing high energy, 1J, 500 ps pulses to 1.5 ps duration with efficiency that exceeds 88.5%. We also considered the feasibility of high efficiency, average power conversion to 515 nm in a range of nonlinear crystals in vacuum. The calculated temperature profiles in large aperture crystals are compared with temperature acceptance bandwidths for the second harmonic generation. It is concluded that in LBO and YCOB crystals the conversion efficiency can exceed 60%, thus allowing generation of 1 kHz train of 1.5 ps pulses at 515 nm with energy exceeding 0.5 J that will be used for pumping the high energy amplifier stages of a femtosecond OPCPA system.

  15. Delay Optimization of Low Power Reversible Gate using MOS Transistor Level design

    Mukesh Kumar Kushwaha

    2015-10-01

    Full Text Available In Semiconductor industry has witnessed and explosive growth of integration of sophisticated multimedia base application onto mobile electronic gadget since the last decade. The critical concern in this aspect is to reduce the power consumption beyond a certain range of operating frequency. An important factor in the design of VLSI circuits is the choices of reversible logic. Basically conventionally digital circuits have been implemented using the logic gates, which were irreversible in nature only NOT gate are reversible. These irreversible gates produce energy loss due to the information bits lost during the operation information loss occurs because the total number of output signals generated is less than total number of input signals applied. In reversible if the input vector can be uniquely recovered from the output vector and if there is a one to one correspondence between its input and output logic. This paper present a new representation of existing reversible gate in MOS transistor. The MOS transistor designing using a gate diffusion input. Those new representation of MOS transistor has a hoping future in design of low power consumption circuits and high speed application

  16. Challenges to maintain the safety level of nuclear power plants in Germany

    One possible tool to identify new challenges is the evaluation of operating experience. For example, the evaluation of operating experience has resulted in the further development of safety standards and regulations. Also, it is highly useful in connection with the identification of generic weak points. The development of safety management systems in German nuclear power plants was initiated in the wake of two events with high safety significance. As a result, the Fundamentals of Safety Management Systems were published by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety in 2004. Another important challenge is the need for an ageing management system in nuclear power plants. In 2004, the German Reactor Safety Commission submitted a comprehensive recommendation on the control of ageing processes. The aim was to include all possible ageing mechanisms. Finally, a further challenge is the increasing tendency to perform realistic or so-called best estimate calculations. Improved analyses increase the degree of certainty associated with calculated safety margins of acceptance criteria. Once this increased margin has been identified, the best possible uses of this gain of margin have to be identified. One of them might be to improve the plant's performance. The lessons learned from these examples can be summarized in the following statement: to maintain safety under changing boundary conditions, progress is necessary. (author)

  17. The embedded pressurizer water-level control system of nuclear power plant

    Based on the analysis of the structure, the function and the running theory of the analog pressurizer water-level control system (APWLCS), the study of the digitization APWLCS is performed in this paper. The PWLCS was obtained based on a mature commercial SBC, considering the conversions of Digital/Analog and Analog/Digital and the control algorithms, and constituted a closed-loop with the pressurizer water-level simulate model to run the system. The control system was checked by the dummy apparatus, and it proved that the system has achieved and exceeded the original analog control system in function and performance. (authors)

  18. ANALYSIS OF HIGH CADENCE IN SITU SOLAR WIND IONIC COMPOSITION DATA USING WAVELET POWER SPECTRA CONFIDENCE LEVELS

    The variability inherent in solar wind composition has implications for the variability of the physical conditions in its coronal source regions, providing constraints on models of coronal heating and solar wind generation. We present a generalized prescription for constructing a wavelet power significance measure (confidence level) for the purpose of characterizing the effects of missing data in high cadence solar wind ionic composition measurements. We describe the data gaps present in the 12 minute Advanced Composition Explorer/Solar Wind Ionic Composition Spectrometer observations of O7+/O6+ during 2008. The decomposition of the in situ observations into 'good measurement' and 'no-measurement' signals allows us to evaluate the performance of a filler signal, i.e., various prescriptions for filling the data gaps. We construct Monte Carlo simulations of synthetic O7+/O6+ composition data and impose the actual data gaps that exist in the observations in order to investigate two different filler signals: one, a linear interpolation between neighboring good data points, and two, the constant mean value of the measured data. Applied to these synthetic data plus filler signal combinations, we quantify the ability of the power spectra significance level procedure to reproduce the ensemble-averaged time-integrated wavelet power per scale of an ideal case, i.e., the synthetic data without imposed data gaps. Finally, we present the wavelet power spectra for the O7+/O6+ data using the confidence levels derived from both the mean value and linear interpolation data gap filling signals and discuss the results

  19. Reducing radiation levels at boiling water reactors of a commercial nuclear power plant fleet

    Boiling Water Reactors (BWRs) have suffered from high radiation fields in the primary loop, typically measured by the 'BRAC' (BWR Radiation Level Assessment and Control) reactor recirculation system (RRS) dose rates. Reactor water chemistry and activated corrosion product measurements are important in understanding changes in radiation fields in components and systems of a BWR. Several studies have been conducted at Exelon Nuclear's 14 BWRs in order to understand more fully the cause and effect relationships between reactor water radioactive species and radiation levels. Various radiation control strategies are utilized to control and reduce radiation levels. The proper measurement of radioactive soluble and insoluble species is a critical component in understanding radiation fields. Other factors that impact radiation fields include: noble metal applications; hydrogen injection; zinc addition; chemistry results; cobalt source term; fuel design and operation. Chemistry and radiation field trending and projections are important tools that assist in assessing the potential for increased radiation fields and aiding outage planning efforts, including techniques to minimize outage dose. This paper will present the findings from various studies and predictor tools as well as provide recommendations for continued research efforts in this field. Current plant data will be shared on reactor water radioactive species, plant radiation levels, zinc addition amounts and other chemistry controls. (author)

  20. Geometrical Optimization for Improved Power Capture of Multi-Level Overtopping Based Wave Energy Converters

    Margheritini, Lucia; Victor, L.; Kofoed, Jens Peter;

    2009-01-01

    In multi-level wave energy converters the water from incoming waves is stored in reservoirs one on top of the other. Prevision formula for the overtopping flow rates in the individual reservoirs is fundamental for dimensioning correctly the turbines and optimizing the device. Having a number of...

  1. Radiation levels at boiling water reactors of a commercial nuclear power plant fleet

    Radiation field control at a Boiling Water Reactor (BWR) is a complex process that requires the application of both theoretical knowledge and practical experience in order to achieve low radiation fields. Older BWRs were usually designed with cobalt containing components, such as Stellite™ materials in valves, control rod blades, turbine blades and others, that contribute to high radiation fields due to the activation of cobalt to Co-60. Newer BWRs are designed with improvements in these areas; however, only the newest BWRs have been designed using low cobalt source term materials for all components in streams that enter the reactor. Control and minimization of the cobalt source term (material that can be activated to Co-60 in the reactor) will ensure that as low as reasonably achievable (ALARA) dose rates are achieved during power operation and during refueling outages. (author)

  2. Combining gigawatt level X-band high power microwave beams with an overmoded circular waveguide diplexer

    The high power microwave (HPM) beam combining results at X-band with an overmoded waveguide diplexer are presented. As the key device for the beam combining experiments, the diplexer is designed, fabricated, and tested. Then the beam combining experiments under short and long pulses are performed at HPM source, respectively. The experiment results reveal that short and long pulse HPM beams have been successfully operated without microwave breakdown at 3-GW with pulse duration of 25 ns and 1.3-GW with pulse duration of 96 ns. According to the experiments, conservative breakdown thresholds for the diplexer are concluded to be 800 kV/cm and 550 kV/cm, respectively, under the short and long pulse HPM conditions

  3. Design of Mobile Device Display for Nuclear Power Plant Maintenance Considering the Level of Expertise

    Maintaining and repairing complex technical facilities such as nuclear power plants requires comprehensive knowledge on a broad range of the system, as well as on operational and safety procedures by the performing maintenance personnel. There exists the need to have access to instruction sheets and parameter tables at the work site. This may not be practicable with printed manuals simply due to their increasing bulk. To cope with this situation, fully mobile wirelessly connected (FMWC) information and communication technologies (ICT) are thought to have high potential for improving field maintenance through increased accessibility and availability of critical information needed in on-site reference or decision making. Among many up-todate technologies, the mobile application to the maintenance support system will be proposed in this paper

  4. Safety insurance of disposal of low level radioactive waste generated from decommissioned nuclear power plant

    The basis technique to affect the safety design of radioactive waste disposal facility is supported by the long-term stability examination for the characterization (the water permeability, absorption and so on) of the various barrier material, development of analysis code to use for the estimation of the material movement and the chemical environment change, and the acquisition of the natural analog data which is used to confirm its validity. It is thought that the effectivity of this basis technique depends on the kind of the waste, but in the field of LLW, it is possible to apply the technique. It this report, it confirmed the basis technique, which is possible to apply to the safety design of the disposal facilities about decommissioning waste from nuclear power plant. For example, activated metal is possible to evaluate using corrosion speed. And the basic data exists to argue about the long-term stability of cement and bentonite as engineered barrier. (author)

  5. Assessment of mass transfer and mixing in rigid lab-scale disposable bioreactors at low power input levels.

    van Eikenhorst, Gerco; Thomassen, Yvonne E; van der Pol, Leo A; Bakker, Wilfried A M

    2014-01-01

    Mass transfer, mixing times and power consumption were measured in rigid disposable stirred tank bioreactors and compared to those of a traditional glass bioreactor. The volumetric mass transfer coefficient and mixing times are usually determined at high agitation speeds in combination with sparged aeration as used for single cell suspension and most bacterial cultures. In contrast, here low agitation speeds combined with headspace aeration were applied. These settings are generally used for cultivation of mammalian cells growing adherent to microcarriers. The rigid disposable vessels showed similar engineering characteristics compared to a traditional glass bioreactor. On the basis of the presented results appropriate settings for adherent cell culture, normally operated at a maximum power input level of 5 W m(-3) , can be selected. Depending on the disposable bioreactor used, a stirrer speed ranging from 38 to 147 rpm will result in such a power input of 5 W m(-3) . This power input will mix the fluid to a degree of 95% in 22 ± 1 s and produce a volumetric mass transfer coefficient of 0.46 ± 0.07 h(-1) . PMID:25139070

  6. Assessment of electromagnetic field levels from surrounding high-tension overhead power lines for proposed land use.

    Al-Bassam, E; Elumalai, A; Khan, A; Al-Awadi, L

    2016-05-01

    The surrounding outdoor environment for new development has a big effect on the indoor quality of life. The main aim of this work was to determine the suitability of the area for building new schools with reference to electromagnetic field (EMF) effects. The specific objective of this study was to detect the safe distance from the EMF posed by the high-tension overhead power lines in the vicinity of the specified area. The measurements were taken for both the electric and magnetic fields in different months in order to detect the highest EMF levels during the peak power load season. EMDEX II with E-probe and EMDEX II with Linda were used for the measurements. These instruments were all calibrated by ENERTECH Company in USA. The EMF associated with high tension transmission lines that surrounded the proposed site has to be below 0.2 μT (Italian EMF regulations are the most suitable regulations for the establishment of schools in Kuwait). The safety clearance distance from the existing 300-kV high-tension power line has been assigned as 200 m and from other existing 132-kV high-tension power line was 50 m. The proposed site with its predefined boundaries has a magnetic field below the Italian EMF regulations for the establishment of new schools. PMID:27129598

  7. Highest manageable level of radioactivity in the waste storage facilities of power plants

    This project presents and discusses an investigation of the highest level of radioactivity possible to handle in the waste storage facilities. The amount of radioactivity, about 0.1% of the fuel inventory, is the same in both of the cases but the amount of water is very different. The hypothetical accident was supposed to be damage of the reactor fuel caused by loss of coolant. (K.A.E.)

  8. Ultrasonics for fluid-level monitoring in nuclear power plant pipes

    Ultrasonic techniques are of great interest for noninvasive physical measurements of fluids in hostile environments. Electricite de France (EdF) has developed several products in this area to monitor sensitive parameters in nuclear plants. As an example, we present a system to monitor the water level of the primary coolant circuit during a refueling outage. Pressurized water reactor refueling requires a plant outage during which the steam generator tubes must be drained. Primary circuit pipes are drained for this purpose. Nevertheless, it is necessary to maintain a minimum level of fluid in the system to guarantee proper operation of the residual heat removal (RHR) system. Damage to the RHR pumps because of drainage of the suction port must be avoided. Fine and accurate monitoring of this operation is difficult using conventional differential pressure level transmitters. Due to several incidents in French nuclear plants regarding RHR operations, the EdF maintenance department (SPT/UTO), in 1988, asked the EdF research and development department (DER) to study and develop a new method of monitoring this critical parameter. The method and results are described

  9. Modelling and control of a seven level NPC voltage source inverter. Application to high power induction machine drive

    Gheraia, H.; Berkouk, E. M.; Manesse, G.

    2001-08-01

    In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction.

  10. Modelling and control of a seven level NPC voltage source inverter. Application to high power induction machine drive

    Gheraia, H.; Berkouk, E.M. [ENP, Alger (Algeria). Lab. de Commande des Processus; Manesse, G. [CNAM-Paris (France). Lab. d' Electricite Industrielle

    2001-08-01

    In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction. (orig.)

  11. LCL filter design for three-phase two-level power factor correction using line impedance stabilization network

    Kouchaki, Alireza; Nymand, Morten

    2016-01-01

    This paper presents LCL filter design method for three-phase two-level power factor correction (PFC) using line impedance stabilization network (LISN). A straightforward LCL filter design along with variation in grid impedance is not simply achievable and inevitably lead to an iterative solution...... for filter. By introducing of fast power switches for PFC applications such as silicon-carbide, major current harmonics around the switching frequency drops in the region that LISN can actively provide well-defined impedance for measuring the harmonics (i.e. 9 kHz- 30MHz). Therefore, LISN can be replaced...... with unknown grid impedance at high frequency, simplify the model of the filter, and provide repetitive measurements. In this paper, all the filter parameters are derived with analyzing the behavior of the converter at high frequency with presence of LISN impedance. The minimum required filter capacitor...

  12. 考虑风剪切的1.3MW风力机整机三维定常流动数值研究%Numerical Study on 3D Steady Flow of a 1.3 MW Wind Turbine Considering Wind Shear Factor

    韩中合; 李引; 季剑

    2011-01-01

    分别采用均匀风和剪切风对1.3 MW失速调节风力机整机在8 m/s和13 m/s来流风速下的绕流流场进行全三维定常数值模拟。根据模拟结果分析叶片不同截面的压力系数分布、沿叶展方向的功率分布、风轮三维流场细节、风轮下游不同距离处的静压分布和二维相对速度矢量分布情况。结果表明:剪切风下,风力机功率计算值与设计值吻合较好;在靠近叶根处,适当地减小有效攻角可提高翼型气动性能,选择适应较大攻角的翼型,可以提高叶根处的输出功率;在靠近叶尖的部位,适当增加有效攻角,同时选择适应小攻角的翼型可以提高叶尖处的输出功率;在叶根部位,发生了明显的流动分离;塔架与轮毂所在位置的下游尾迹处产生的漩涡和干扰要远远大于叶轮面其他部位。%A numerical simulation on 3D steady flow around a 1.3 MW stall-regulated wind turbine was carried out at wind speeds of 8 m/s and 13 m/s respectively under uniform and shear wind conditions,based on which following factors were analyzed,such as the pressure coefficient distribution at different sections,the loading distribution along the span of rotor blade,the 3D flow detail of wind rotor,the static pressure distribution and the 2D velocity vector distribution at different sections in the z-direction.Results show that the simulated data of turbine power agree well with that of the design under shear wind conditions;the power output at blade root can be increased by properly reducing the effective attack angle to improve the aerodynamic performance or by choosing an airfoil with a large attack angle for the root area;whereas at the blade tip,the power output can be increased by raising the effective attack angle properly or by choosing an airfoil with a smaller attack angle;obvious flow separation occurs at blade root;the wake vortex and its disturbance in the downstream of tower and hub are much larger than those in

  13. Assessment of the Current Level of Automation in the Manufacture of Fuel Cell Systems for Combined Heat and Power Applications

    Ulsh, M.; Wheeler, D.; Protopappas, P.

    2011-08-01

    The U.S. Department of Energy (DOE) is interested in supporting manufacturing research and development (R&D) for fuel cell systems in the 10-1,000 kilowatt (kW) power range relevant to stationary and distributed combined heat and power applications, with the intent to reduce manufacturing costs and increase production throughput. To assist in future decision-making, DOE requested that the National Renewable Energy Laboratory (NREL) provide a baseline understanding of the current levels of adoption of automation in manufacturing processes and flow, as well as of continuous processes. NREL identified and visited or interviewed key manufacturers, universities, and laboratories relevant to the study using a standard questionnaire. The questionnaire covered the current level of vertical integration, the importance of quality control developments for automation, the current level of automation and source of automation design, critical balance of plant issues, potential for continuous cell manufacturing, key manufacturing steps or processes that would benefit from DOE support for manufacturing R&D, the potential for cell or stack design changes to support automation, and the relationship between production volume and decisions on automation.

  14. INFLUENCES OF THE PURCHASING POWER CHANGE ON THE EVOLUTION OF THE AGROALIMETARY MARKETS ON EUROPEAN UNION LEVEL

    Laura Catalina Timiras

    2014-01-01

    Full Text Available This paper aims to identify the manifested connection between the dynamics of the population purchasing power and the dynamic of agroalimentary markets in general as well as by product types on European Union level. Based on the last data supplied by Eurostat 2013, using the specific methods for studying the correlations, we have detected that increases and decreases of the purchasing power generated similar changes on agroalimentary markets level from the point of view of achieved sales in most of the poorer countries of the European Union, but not in those states which got beyond the average gross domestic product per capita of the European Union. This relationship has been noticed only on the agroalimentary markets as a whole (respectively on the amounts spent by the population for purchasing agroalimentary goods, beverages and tobacco, but not on the level of markets of various types of product (“meat and meat products”, “fruit and vegetables”, “dairy produce, eggs and edible oils and fats”, “beverages”, “sugar and chocolate and sugar confectionery”, “tobacco products”.

  15. Daytime edema levels with plus powered low and high water content hydrogel contact lenses.

    La Hood, D

    1991-11-01

    Eleven unadapted contact lens wearers wore a high (74%) water content hydrogel lens (Permaflex, CooperVision) of oxygen transmissibility Dk/Lav 14 x 10(-9) in one eye and a low (43%) water content hydrogel lens (Aquaflex Superthin) of Dk/Lav 4 x 10(-9) in the other eye under open-eye conditions for 8 h. After 8 h, average corneal edema for the lower water content lens was 7.9 +/- 2.6%, which was significantly more than that for the higher water content lens, 1.7 +/- 1.6%. Significantly fewer corneal striae and folds were also seen in the eyes wearing the higher water content lens. Subjective ratings of lens comfort were significantly better for the higher water content lens. Low water content positive power hydrogel lenses of the thicknesses used in this study place unacceptable hypoxic stress on the cornea and therefore should not be used for all-day wear. PMID:1766650

  16. Assay of long-lived radionuclides in low-level wastes from power reactors

    The 10 CFR Part 61 waste classification system includes several nuclides which are difficult to assay without expensive radiochemical methods. In order for waste generators to classify wastes practically, NRC Staff has recommended the use of correlation factors to scale the difficult-to-measure nuclides with nuclides which can be measured more easily (i.e., gamma emitters such as 60Co or 137Cs). In this study, Science Applications International Corporation (SAIC) performed complete radiochemical assays for all the 10 CFR Part 61 waste classification nuclides on over 100 samples. These data, along with almost 800 other samples in the SAIC data base, were used to assess the validity of correlation factors suggested for use in nuclear power plant wastes. Specific generic correlation factors are recommended with other approaches to correlate nuclides for which generic scaling factors are not defensible. The primary nuclide correlations studied were 14C, 55Fe, 59Ni, 63Ni, and 94Nb, with 60Co; 90Sr, 99Tc, 129I, 135Cs, and /sup 239, 240/Pu with 137Cs; 238Pu, /sup 239, 240/Pu, 241Pu, 241Am, 242Cm, and /sup 243, 244/Cm with 144Ce; and 238Pu, 241Pu, 241Am, 242Cm and /sup 243, 244/Cm with /sup 239, 240/Pu

  17. Generic conditional clearance for very low level active charcoal generated in nuclear power plant operation

    This report proposes a generic conditional exemption to the very low level active charcoal generated in the operation of a NPP. The project has been developed in two parts: a common one (applied to the stream to be exempted) and a specific one (specific to the NPP that fulfills already the common part requirements). The common project specifies the methodology and the disposal options. It provides derived exemption levels and maximum amount of activity the exemption of which be feasible, demonstrating the viability of their conventional management. The specific project of each NPP will develop the amount of waste to be managed and other details that supplement the previous project, adjusting to the methodology and disposal options in the common project. The proposed management suggestion consists in burning the waste in a coal-burning plant and disposing of the scum in a controlled landfill. The resultant radiological dose is considered negligible according to the document Safety Series N 89 of the IAEA. The calculation of the radiological dose associated to several stages has been carried out using the IMPACTS-BRC code, contained in NUREG/CR-3585 and NUREG/5517. The methodology used in the radiological dose evaluation is as recommended in the Safety Guide n. 7.8 of the Spanish Nuclear Safety Council. (Author)

  18. Human reliability analysis for level-1 PSA study of Indian nuclear power plants

    Full text: Probabilistic safety studies show that human actions contribute significantly to overall safety in nuclear power plants (NPPs). The contribution of potential human errors to risk is quantitatively assessed in a human reliability analysis (HRA) study in terms of human error probabilities (HEPs) and used to arrive at ways to improve human performance. HRA is thus integral to a probabilistic safety assessment (PSA). In order to handle various emergency conditions such as process or support system failure, which can arise in the plant, a set of emergency operating procedures (EOPs) are developed and provided to NPP operators. Operators are trained to diagnose the event that has occurred and then select and carry out the EOP. Human interaction involved in the execution of an EOP plays an important role in determining the course of an event. If errors occur and operators fail to recover from them, the situation can get aggravated and even result in the event turning into an accident. It is therefore essential to carry out a HRA study for EOPs and determine the human interactions that are the dominant contributors to risk. This would enable designers to implement necessary modifications in procedures and/or develop operator aids to support reliable human performance. This paper first discusses the HRA study carried out for the EOP for station blackout (SBO) event in an Indian pressurised heavy water reactor (IPHWR) and then a study for active process water system (APWS) failure event in advanced heavy water reactor (AHWR). Human reliability quantification has been done using accident sequence evaluation programme (ASEP) which is an accident sequence, data driven HRA technique. The HRA covers event detection and diagnosis and post-diagnosis actions involved. The details of human reliability assessment are given in the paper

  19. A new method to estimate implied equity risk premiums: The level of premiums and their explanatory power

    Lindroos, Mikko

    2013-01-01

    The main objective of the study is to determine the level of implied equity risk premiums from two models and to analyse their explanatory power in terms of future realized equity risk premiums. The paper studies a new method to estimate implied premiums and validates the results by a comparison to an established model. Luoma and Sahlström (2009) presented their model to estimate implied equity risk premiums by looking at an earn back period calculated from analysts' earnings forecasts, the c...

  20. Radiochemical methodologies applied to determination of zirconium isotopes in low-level waste samples from nuclear power plants

    The 93Zr determination in low-level radioactive wastes generated at nuclear power plants is an important issue for waste disposal purpose. This paper describes an analytical methodology developed for 93Zr determination based on selective separation using extractive resins associated with inductively coupled plasma mass spectrometry (ICP-MS) and liquid scintillation counting (LSC) measurements. The 93Zr results obtained for waste samples were in a good agreement for both techniques and the detection limits of 0.045 μg L-1 and 0.05 Bq L-1 were obtained for ICP-MS and LSC techniques respectively. (author)

  1. Rapid determination of uranium isotopes in low and intermediate level wastes from nuclear power plants by alpha spectrometry

    A simple and fast method for uranium isotopes determination in low and intermediate level wastes from nuclear power plants using extraction chromatography is described. Following sample preparation, uranium is pre-concentrated by precipitation with iron(III) hydroxide and then separated using Dowex AG 1X8, 100-200mesh, resin. The separated uranium is electrodeposited onto stainless-steel discs and then measured by alpha spectrometry and the results were analyzed using WinALPHA software. The procedure was evaluated using 232U radiotracer. USGS uranium standard and intercomparison program were used as quality tools. (author)

  2. Inspections of radiocesium concentration levels in rice from Fukushima Prefecture after the Fukushima Dai-ichi Nuclear Power Plant accident

    Nihei, Naoto; Tanoi, Keitaro; Nakanishi, Tomoko M.

    2015-03-01

    We summarize the inspections of radiocesium concentration levels in rice produced in Fukushima Prefecture, Japan, for 3 years from the nuclear accident in 2011. In 2011, three types of verifications, preliminary survey, main inspection, and emergency survey, revealed that rice with radiocesium concentration levels over 500 Bq/kg (the provisional regulation level until March 2012 in Japan) was identified in the areas north and west of the Fukushima nuclear power plant. The internal exposure of an average adult eating rice grown in the area north of the nuclear plant was estimated as 0.05 mSv/year. In 2012, Fukushima Prefecture authorities decided to investigate the radiocesium concentration levels in all rice using custom-made belt conveyor testers. Notably, rice with radiocesium concentration levels over 100 Bq/kg (the new standard since April 2012 in Japan) were detected in only 71 and 28 bags out of the total 10,338,000 in 2012 and 11,001,000 in 2013, respectively. We considered that there were almost no rice exceeding 100 Bq/kg produced in Fukushima Prefecture after 3 years from the nuclear accident, and the safety of Fukushima's rice were ensured because of the investigation of all rice.

  3. M4D: a powerful tool for structured programming at assembly level for MODCOMP computers

    Structured programming techniques offer numerous benefits for software designers and form the basis of the current high level languages. However, these techniques are generally not available to assembly programmers. The M4D package was therefore developed for a large project to enable the use of structured programming constructs such as DO.WHILE-ENDDO and IF-ORIF-ORIF...-ELSE-ENDIF in the assembly code for MODCOMP computers. Programs can thus be produced that have clear semantics and are considerably easier to read than normal assembly code, resulting in reduced program development and testing effort, and in improved long-term maintainability of the code. This paper describes the M4D structured programming tool as implemented for MODCOMP'S MAX III and MAX IV assemblers, and illustrates the use of the facility with a number of examples

  4. Procedures for conducting probabilistic safety assessments of nuclear power plants (Level 1)

    This report provides guidance for conducting a Level 1 of probabilistic safety assessment (PSA), that is a PSA concerned with events leading to core damage. The scope of this report is confined to internal initiating events (excluding internal fires and floods). A particular aim is to promote a standardized framework, terminology and form of documentation for PSAs so as to facilitate external review of the results of such studies. The report is divided into the following major sections: management and organization; identification of sources of radioactive releases and accident initiators; accident sequence modelling; data assessment and parameter estimation; accident sequence quantification; documentation of the analysis: display and interpretation of result. 45 refs, 7 figs, 23 tabs

  5. Disposal of high-level waste from nuclear power plants in Denmark. v.3

    The present report deals with material testing as part of the investigations regarding a repository for high-level waste in a salt dome. It is volume 3 of five volumes that together constitute the final report of the Danish utilities' salt dome investigations. The material testing programme chiefly comprised laboratory investigations and analyses of material samples, partly obtained from the salt dome in question and partly from the overlying geological formation. The test programme was fully completed for Eslev salt dome on Mors. Chemical analyses and mineralogical investigations were carried out in order to determine the type and extent of the impurities confined in the rock salt. Moreover, a programme was carried out to investigate the water content of the salt. Temperature conditions around a repository, the strenght and creep properties of the salt were investigated in order to determine whether drill holes, shafts and mine galleries could be constructed and maintained intact within the period of time required to complete the disposal of high-level waste. Chemical analysis were carried out in order to determine which substances are found dissolved in the water contained by the geological formation overlying the salt dome, as well as chemical/physical investigations regarding the water content, porosity, velocity of a possible leak of radioactive waste products, etc. Materials that would be introduced into a repository were studied with regard to their corrosion resistance in the salt environment. Concrete materials were investigated and characterized for their use in the final sealing of the access routes to the repository through the geological formation. (BP)

  6. Minimization program of low-level radioactive waste at nuclear power plants in Taiwan

    This paper reviews the strategy and source/volume reduction practices of the LLRW minimization program implemented in Taiwan over the past decades. The LLRW minimization program in Taiwan includes LLRW minimization regulation/strategy, source reduction and volume reduction. The Radioactive Waste Management Policy was promulgated by the Executive Yuan on September 16, 1988 and revised on September 2, 1997. In accordance with the policy, radwaste producers shall endeavor to minimize the amounts and volumes of radwaste productions. Several activities of source reduction and volume reduction have already done, such as adapted equipment change to improve the liquid filter performance in radwaste treatment system, good housekeeping and administration control in radiation control area to reduce the dry radwaste generation, a high efficiency solidification technology (HEST) was developed by the Institute of the Nuclear Energy Research (INER) and successfully implemented at the MSNPP, The Volume Reduction Center (VRC) located at the KSNPP site was put in operation. As a result of persistent efforts over the past two decades, the annual solidified radwaste generated has been reduced from a high level at 12,258 drums per year in 1983 to less than 5,000 drums in 1992 and further down to 259 drums in 2007. The amount of annual solidified radwaste generated currently has been significantly reduced to 2% of the peak. In addition, the annual dry radwaste generated has been reduced from a high level at 7,571 drums per year in 1990 to less than 2,125 drums in 2007. The amount of annual dry radwaste generated also has significantly reduced to 28% of the peak. (author)

  7. An ultra-low power self-timed column-level ADC for a CMOS pixel sensor based vertex detector

    Zhang, L.; Wang, M.

    2014-11-01

    The International Large Detector (ILD) is a detector concept for the future linear collider experiment. The vertex detector is the key tool to achieve high precision measurements for flavor tagging, which puts stringent requirements on the CMOS pixel sensors. Due to the cooling systems which deteriorate the material budget and increase the multiple scattering, it is important to reduce the power consumption. This paper presents an ultra-low power self-timed column-level ADC for the CMOS pixel sensors, aiming to equip the outer layers of the vertex detector. The ADC was designed to operate in two modes (active and idle) adapted to the low hit density in the outer layers. The architecture employs an enhanced sample-and-hold circuit and a self-timed technique. The total power consumption with a 3-V supply is 225μW during idle mode, which is the most frequent situation. This value rises to 425μW in the case of the active mode. It occupies an area of 35 × 590μm2.

  8. An ultra-low power self-timed column-level ADC for a CMOS pixel sensor based vertex detector

    The International Large Detector (ILD) is a detector concept for the future linear collider experiment. The vertex detector is the key tool to achieve high precision measurements for flavor tagging, which puts stringent requirements on the CMOS pixel sensors. Due to the cooling systems which deteriorate the material budget and increase the multiple scattering, it is important to reduce the power consumption. This paper presents an ultra-low power self-timed column-level ADC for the CMOS pixel sensors, aiming to equip the outer layers of the vertex detector. The ADC was designed to operate in two modes (active and idle) adapted to the low hit density in the outer layers. The architecture employs an enhanced sample-and-hold circuit and a self-timed technique. The total power consumption with a 3-V supply is 225μW during idle mode, which is the most frequent situation. This value rises to 425μW in the case of the active mode. It occupies an area of 35 × 590μm2

  9. A low-power and small-area column-level ADC for high frame-rate CMOS pixel sensor

    Zhang, L.; Morel, F.; Hu-Guo, C.; Hu, Y.

    2014-07-01

    CMOS pixel sensors (CPS) have demonstrated performances meeting the specifications of the International Linear Collider (ILC) vertex detector (VTX). This paper presents a low-power and small-area 4-bit column-level analog-to-digital converter (ADC) for CMOS pixel sensors. The ADC employs a self-timed trigger and completes the conversion by performing a multi-bit/step approximation. As in the outer layers of the ILC vertex detector hit density is of the order of a few per thousand, in order to reduce power consumption, the ADC is designed to work in two modes: active mode and idle mode. The ADC is fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. It is implemented with 48 columns in a sensor prototype. Each column ADC covers an area of 35 ×545 μm2. The measured temporal noise and Fixed Pattern Noise (FPN) are 0.96 mV and 0.40 mV, respectively. The power consumption, for a 3 V supply and 6.25 MS/s sampling rate, is 486 μW during idle time, which is by far the most frequently employed one. This value rises to 714 μW in the case of the active mode. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.49/-0.28 LSB and 0.29/-0.20 LSB, respectively.

  10. Coal-fired power-plant-capital-cost estimates. Final report. [Mid-1978 price level; 13 different sites

    Holstein, R.A.

    1981-05-01

    Conceptual designs and order-of-magnitude capital cost estimates have been prepared for typical 1000-MW coal-fired power plants. These subcritical plants will provide high efficiency in base load operation without excessive efficiency loss in cycling operation. In addition, an alternative supercritical design and a cost estimate were developed for each of the plants for maximum efficiency at 80 to 100% of design capacity. The power plants will be located in 13 representative regions of the United States and will be fueled by coal typically available in each region. In two locations, alternate coals are available and plants have been designed and estimated for both coals resulting in a total of 15 power plants. The capital cost estimates are at mid-1978 price level with no escalation and are based on the contractor's current construction projects. Conservative estimating parameters have been used to ensure their suitability as planning tools for utility companies. A flue gas desulfurization (FGD) system has been included for each plant to reflect the requirements of the promulgated New Source Performance Standards (NSPS) for sulfur dioxide (SO/sub 2/) emissions. The estimated costs of the FGD facilities range from 74 to 169 $/kW depending on the coal characteristics and the location of the plant. The estimated total capital requirements for twin 500-MW units vary from 8088 $/kW for a southeastern plant burning bituminous Kentucky coal to 990 $/kW for a remote western plant burning subbituminous Wyoming coal.

  11. Stand by Leakage Power Reduction in Nanoscale Static CMOS VLSI Multiplier Circuits Using Self Adjustable Voltage Level Circuit

    Deeprose Subedi

    2012-10-01

    Full Text Available In this paper, we performed the comparative analysis of stand-by leakage (when the circuit is idle, delay and dynamic power (when the circuit switches of the three different parallel digital multiplier circuits implemented with two adder modules and Self Adjustable Voltage level circuit (SVL. The adder modules chosen were 28 transistor-conventional CMOS adder and 10 transistor- Static Energy Recovery CMOS adder (SERF circuits. The multiplier modules chosen were 4Bits Array, 4 bits Carry Save and 4 Bits Baugh Wooley multipliers. At first, the circuits were simulated with adder modules without applying the SVL circuit. And secondly, SVL circuit was incorporated in the adder modules for simulation. In all the multiplier architectures chosen, less standby leakage power was observed being consumed by the SERF adder based multipliers applied with SVL circuit. The stand-by leakage power dissipation is 1.16µwatts in Bits array multiplier with SERF Adder applied with SVL vs. 1.39µwatts in the same multiplier with CMOS28T Adder applied with SVL circuit. It is 1.16µwatts in Carry Save multiplier with SERF Adder applied with SVL vs. 1.4µwatts in the same multiplier with CMOS 28T Adder applied with SVL circuit. It is 1.67µwatts in Baugh Wooley multiplier with SERF Adder applied with SVl circuit vs. 2.74µwatts in the same multiplier with CMOS 28T Adder applied with SVL circuit.

  12. Stand by Leakage Power Reduction in Nanoscale Static CMOS VLSI Multiplier Circuits Using Self Adjustable Voltage Level Circuit

    Deeprose Subedi

    2012-11-01

    Full Text Available In this paper, we performed the comparative analysis of stand-by leakage (when the circuit is idle, delay and dynamic power (when the circuit switches of the three different parallel digital multiplier circuits implemented with two adder modules and Self Adjustable Voltage level circuit (SVL. The adder modules chosen were 28 transistor-conventional CMOS adder and 10 transistor- Static Energy Recovery CMOS adder (SERF circuits. The multiplier modules chosen were 4Bits Array, 4bits Carry Save and 4Bits Baugh Wooley multipliers. At first, the circuits were simulated with adder modules without applying the SVL circuit. And secondly, SVL circuit was incorporated in the adder modules for simulation. In all the multiplier architectures chosen, less standby leakage power was observed being consumed by the SERF adder based multipliers applied with SVL circuit. The stand-by leakage power dissipation is 1.16µwatts in Bits array multiplier with SERF Adder applied with SVL vs. 1.39µwatts in the same multiplier with CMOS28T Adder applied with SVL circuit. It is 1.16µwatts in Carry Save multiplier with SERF Adder applied with SVL vs. 1.4µwatts in the same multiplier with CMOS 28T Adder applied with SVL circuit. It is 1.67µwatts in Baugh Wooley multiplier with SERF Adder applied with SVl circuit vs. 2.74µwatts in the same multiplier with CMOS 28T Adder applied with SVL circuit.

  13. Calculated in-air leakage spectra and power levels for the ANSI standard minimum accident of concern. Final report

    This document represents Phase I of a two-phase project. The entire project consists of determining a series of minimum accidents of concern and their associated neutron and photon leakage spectra that may be used to determine Criticality Accident Alarm compliance with ANSI/ANS-8.3. The inadvertent assembly of a critical mass of material presents a multitude of unknown quantities. Depending on the particular process, one can make an educated guess as to fissile material. In a gaseous diffusion cascade, this material is assumed to be uranyl fluoride. However, educated assumptions cannot be readily made for the other variables. Phase I of this project is determining a bounding minimum accident of concern and its associated neutron and photon leakage spectra. To determine the composition of the bounding minimum accident of concern, work was done to determine the effects of geometry, moderation level, and enrichment on the leakage spectra of a critical assembly. The minimum accident of concern is defined as the accident that may be assumed to deliver the equivalent of an absorbed dose in free air of 20 rad at a distance of 2 meters from the reacting material within 60 seconds. To determine this dose, an analyst makes an assumption and choose an appropriate flux to dose response function. The power level required of a critical assembly to constitute a minimum accident of concern depends heavily on the response function chosen. The first step in determining the leakage spectra was to attempt to isolate the effects of geometry, after which all calculations were conducted on critical spheres. The moderation level and enrichment of the spheres were varied and their leakage spectra calculated. These spectra were then multiplied by three different response functions: the Henderson Flux to Dose conversion factors, the ICRU 44 Kerma in Air, and the MCNP Heating Detector. The power level required to produce a minimum accident of concern was then calculated for each combination

  14. Bituminization system of low level liquid waste in Genkai Nuclear Power Plant

    The bituminization system for low level radioactive liquid wastes has such advantages as its volume reduction is 6 to 10 times higher than the cementing systems, and the exuding ratio of radioactive nuclides from bituminized body into sea water is smaller, because the solids containing radioactive nuclides are solidified into oily bitumen which is very water repellent. Therefore, Genkai No.2 reactor plant has adopted the batch bituminization system, the main equipment of which being a drum mixer. This equipment has the capacity of treating 35 m3 of drain from the machines (boron 21,000 ppm) yearly, mainly composed of boric acid, and 85 m3 of floor drain/laundry drain yearly (solids 1.1 wt.%). This paper describes the outline of the system, the improvement of the installation, operating method, operation control, and the results of cold and hot operations. At the beginning of the trial operation, the concentrated laundry drain from No.1 reactor during the regular inspection was bituminized, and the concentrated sodium borate solution from No.2 reactor was treated since July, 1980. These results show the good volume reduction, condensate-processing capability, mixer controllability and mixer decontamination efficiency. (Wakatsuki, Y.)

  15. Experimental and analytical study of loss-of-flow transients in EBR-II occurring at decay power levels

    A series of eight loss-of-flow (LOF) tests have been conducted in EBR-II to study the transition between forced and natural convective flows following a variety of loss-of-primary-pumping power conditions from decay heat levels. Comparisons of measurements and pretest/posttest predictions were made on a selected test. Good agreements between measurements and predictions was found prior to and just after the flow reaching its minimum, but the agreement is not as good after that point. The temperatures are consistent with the flow response and the assumed decay power. The measured results indicate that the flows of driver and the instrumented subassemblies are too much in the analytical model in the natural convective region. Although a parametric study on secondary flow, turbulent-laminar flow transition, heat transfer ability of the intermediate heat exchange at low flow and flow mixing in the primary tank has been performed to determine their effects on the flow, the cause of the discrepancy at very low flow level is still unknown

  16. A three-dimensional electret-based micro power generator for low-level ambient vibrational energy harvesting

    A novel three-dimensional (3D) electret-based micro power generator with multiple vibration modes has been developed, which is capable of converting low-level ambient kinetic energy to electrical energy. The device is based on a rotational symmetrical resonator which consists of a movable disc-shaped seismic mass suspended by three sets of spiral springs. Experimental analysis shows that the proposed generator operates at an out-of-plane direction at mode I of 66 Hz and two in-plane directions at mode II of 75 Hz and mode III of 78.5 Hz with a phase difference of about 90°. A corona localized charging method is also proposed that employs a shadow mask and multiple discharge needles for the production of micro-sized electret array. From tests conducted at an acceleration of 0.05 g, the prototype can generate a maximum power of 4.8 nW, 0.67 nW and 1.2 nW at vibration modes of I, II and III, respectively. These values correspond to the normalized power densities of 16 µW cm−3 g−2, 2.2 µW cm−3 g−2 and 4 µW cm−3 g−2, respectively. The results show that the generator can potentially offer an intriguing alternative for scavenging low-level ambient energy from 3D vibration sources. (paper)

  17. Alpha spectral power and coherence in the patients with mild cognitive impairment during a three-level working memory task

    2007-01-01

    Objective: The functional relationship between calculated alpha band spectral power and inter-/intra-hemispheric coherence during a three-level working memory task of patients with mild cognitive impairment (MCI) was investigated. Methods:Subjects included 35 MCI patients according to the DSM-Ⅳ criteria (mean age: 62.3, SD: 6.5) and 34 healthy controls (mean age:57.4, SD: 4.0) were selected from the community at large. All subjects performed a simple calculation and recall task with three levels of working memory load while electroencephalograph (EEG) signal was recorded. The spectral EEG power was computed over alphal (8.0~10.0 Hz) and alpha2 (10.5~13.0 Hz) frequency bands and was compared between rest stage and working memory processing stage by two-way ANOVA. Post hoc testing analyzed the differences between each two levels of working memory load during task processing. The inter-hemisphere EEG coherence of frontal (F3-F4), central (C3-C4), parietal (P3-P4), temporal (T5-T6) as well as occipital (O1-O2) was compared between MCI patients and normal controls. The EEG signals from F3-C3,F4-C4, C3-P3, C4-P4, P3-O1, P4-O2, T5-C3, T6-C4, T5-P3 and T6-P4 electrode pairs resulted from the intra-hemispheric action for alphal and alpha2 frequency bands. Result: There was significantly higher EEG power from MCI patients than from normal controls both at rest and during working memory processing. Significant differences existed between rest condition and three-level working memory tasks (P<0.001). The inter- and intra-hemispheric coherence during working memory tasks showed a "drop to rise" tendency compared to that at rest condition. There was significantly higher coherence in MCI patients than in the controls.When task difficulties increased, the cortical connectivity of intra-hemispheric diminished while the inter-hemispheric connectivity dominantly maintained the cognitive processing in MCI patients. Conclusion: The results of the present study indicate that the

  18. Peer review of the Barselina Level 1 probabilistic safety assessment of the Ignalina Nuclear Power Plant, Unit 2

    The Barselina Project is a Swedish-funded, cooperative effort among Lithuania, Russia and Sweden to transfer Western probabilistic safety assessment (PSA) methodology to the designers/operators of Ignalina Nuclear Power Plant (INPP). The overall goal is to use the PSA as a tool for assessing plant operational safety. The INPP is a two-unit, Former Soviet Union-designed nuclear facility located in Lithuania. The results of this PSA will ultimately be used to identify plant-specific improvements in system design and the conduct of facility operations, allowing improved operational safety. Pacific Northwest Laboratory (PNL) was asked to perform an independent expert peer review of the Barselina PSA. This report documents the findings of this review. This review, financed with nuclear safety assistance funds through the US Agency for International Development (USAID) and the US Department of Energy (DOE), satisfies Task II of the PNL peer review of the Barselina project. The objective is to provide an independent, in-proce ss examination of the Barselina Level 1 PSA of Ignalina Nuclear Power Plant, Unit 2. The review consisted of an investigation of the project documentation, interviews, and extensive discussions with the PSA staff during critical stages of the project. PNL assessed the readability, completeness, consistency, validity, and applicability of the PSA. The major aspects explored were its purpose, major assumptions, analysis/modeling, results, and interpretation. It was not within the scope of this review to perform plant walkdowns or to review material other than the PSA documentation

  19. An Approach for the Cooperative Control of FES With a Powered Exoskeleton During Level Walking for Persons With Paraplegia.

    Ha, Kevin H; Murray, Spencer A; Goldfarb, Michael

    2016-04-01

    This paper describes a hybrid system that combines a powered lower limb exoskeleton with functional electrical stimulation (FES) for gait restoration in persons with paraplegia. The general control structure consists of two control loops: a motor control loop, which utilizes joint angle feedback control to control the output of the joint motor to track the desired joint trajectories, and a muscle control loop, which utilizes joint torque profiles from previous steps to shape the muscle stimulation profile for the subsequent step in order to minimize the motor torque contribution required for joint angle trajectory tracking. The implementation described here incorporates stimulation of the hamstrings and quadriceps muscles, such that the hip joints are actuated by the combination of hip motors and the hamstrings, and the knee joints are actuated by the combination of knee motors and the quadriceps. In order to demonstrate efficacy, the control approach was implemented on three paraplegic subjects with motor complete spinal cord injuries ranging from levels T6 to T10. Experimental data indicates that the cooperative control system provided consistent and repeatable gait motions and reduced the torque and power output required from the hip and knee motors of the exoskeleton compared to walking without FES. PMID:25915961

  20. National-level infrastructure and economic effects of switchgrass cofiring with coal in existing power plants for carbon mitigation.

    Morrow, William R; Griffin, W Michael; Matthews, H Scott

    2008-05-15

    We update a previously presented Linear Programming (LP) methodology for estimating state level costs for reducing CO2 emissions from existing coal-fired power plants by cofiring switchgrass, a biomass energy crop, and coal. This paper presents national level results of applying the methodology to the entire portion of the United States in which switchgrass could be grown without irrigation. We present incremental switchgrass and coal cofiring carbon cost of mitigation curves along with a presentation of regionally specific cofiring economics and policy issues. The results show that cofiring 189 million dry short tons of switchgrass with coal in the existing U.S. coal-fired electricity generation fleet can mitigate approximately 256 million short tons of carbon-dioxide (CO2) per year, representing a 9% reduction of 2005 electricity sector CO2 emissions. Total marginal costs, including capital, labor, feedstock, and transportation, range from $20 to $86/ton CO2 mitigated,with average costs ranging from $20 to $45/ton. If some existing power plants upgrade to boilers designed for combusting switchgrass, an additional 54 million tons of switchgrass can be cofired. In this case, total marginal costs range from $26 to $100/ton CO2 mitigated, with average costs ranging from $20 to $60/ton. Costs for states east of the Mississippi River are largely unaffected by boiler replacement; Atlantic seaboard states represent the lowest cofiring cost of carbon mitigation. The central plains states west of the Mississippi River are most affected by the boiler replacement option and, in general, go from one of the lowest cofiring cost of carbon mitigation regions to the highest. We explain the variation in transportation expenses and highlight regional cost of mitigation variations as transportation overwhelms other cofiring costs. PMID:18546680

  1. Factors Affecting the Optimum Seeding Level of Coal or Char-Fired, Open-Cycle MHD Power Plants

    separation temperature of the bulk of the liquid slag from the combustion products. This temperature should be just above the seed condensation initiation temperature for minimum silica recycle with minimum seed loss. Data are presented which illustrate the above factors for a bituminous coal at sulphur levels of 0.5 and 4 wt% sulphur and a bituminous coal char. Seeding materials, considered are potassium carbonate and potassium sulphate. A combustor pressure of 5 atm is assumed with the air-preheat temperature used as a parameter. The results show an increase in electrical conductivity of the combustion products when the sulphur level of the system is reduced. One way of effecting this reduction is to remove the sulphur from the spent seed-silica mixture before its return to the combustor. In addition to increased conductivity, this reduced sulphur mode of operation also allows an MHD/steam power plant to be operated free of sulphur oxide effluent gases. (author)

  2. IFE chamber dry wall materials response to pulsed X-rays and ions at power-plant level fluences

    We have begun a collaborative investigation of the response of candidate first-wall inertial fusion energy (IFE) reactor chamber drywall materials to X-rays on the Z facility, and to ions on RHEPP-1, both located at Sandia National Laboratories. Dose levels are comparable to those anticipated in future direct-drive reactors. Due to the 5-10 Hz repetition rate expected in such reactors, per-pulse effects such as material removal must be negligible. The primary wall materials investigated here are graphite and tungsten in various forms. After exposure on either RHEPP or Z, materials were analyzed for roughening and/or material removal (ablation) as a function of dose. Graphite is observed to undergo significant ablation/sublimation in response to ion exposure at the 3-4 J/cm2 level, significantly below doses expected in future dry-wall power plants. Evidence of thermomechanical stresses resulting in material loss occurs for both graphite and tungsten, and is probably related to the pulsed nature of the energy delivery. These effects are not seen in typical magnetic fusion energy (MFE) conditions where these same kinds of materials are used. Results are presented for thresholds below which no roughening or ablation occurs. Use of graphite in a 'velvet' two-dimensional form may mitigate the effects seen with the flat material, and alloying tungsten with rhenium may reduce its roughening due to the increased ductility of the alloy

  3. An Artificial Neural Network Controller for Three-level Shunt Active Filter to Eliminate the Current Harmonics and Compensate Reactive Power

    Chennai Salim

    2011-09-01

    Full Text Available The increased use of nonlinear devices in the industry has resulted in the direct increase of harmonic distortion in power systems during these last years. Active filter systems are proposed to mitigate current harmonics generated by nonlinear loads. The conventional scheme based on a two-level voltage source inverter controlled by a hysteresis controller has several disadvantages and cannot be used for medium or high-power applications. To overcome these drawbacks and improve the APF performance, there’s a great tendency to use multilevel inverters controlled by intelligent controllers. Three level (NPC inverter is one of the most widely used topologies in various industrial applications such as machine drives and power factor compensators. On the other hand, artificial neural networks are under study and investigation in other power electronics applications. In order to gain the advantages of the three-level inverter and artificial neural networks and to reduce the complexity of classical control schemes, a new active power filter configuration controlled by two MLPNN (Multi-Layer Perceptron Neural Network is proposed in this paper. The first ANN is used to replace the PWM current controller, and the second one to maintain a constant dc link voltage across the capacitors and compensate the inverter power losses. The performance of the global system, including power and control circuits is evaluated by Matlab-Simulink and SimPowerSystem Toolbox simulation. The obtained results confirm the effectiveness of the proposed control scheme.

  4. Actions taken on better earthquake resistance, level improvement and automation in the power distribution equipment; Haiden setsubi no taishin, kodoka, jidoka eno torikumi

    Hara, N. [Agency of Natural Resources and Energy, Tokyo (Japan)

    1995-07-01

    This paper summarizes measures on earthquake resistance, level improvement and automation in power distribution equipment. Earthquake resistance in supports, transformers, wires, incoming lines, and underground wire ways has been handled in Japan according to the `technical criteria for electric facilities`. This is, however, compelled of reviewing with the great earthquake in 1995 as a turning point. Points of discussions include the review on earthquake resistance (considering earthquakes that occur directly below urban areas), improvement in urban power distribution network (network expansion and embedding the transmission lines), and emergency actions upon occurrence of disasters. The contents of the level improvement and automation may be summarized as follows: monitoring and control of distribution line devices including switch operation, automatic collection of power distribution management information intended of improving efficiency in the business operation, concentrated load control to achieve leveling of power loads, automatic meter-reading on power meters, and establishment of automatic and general power distribution system aiming at making common the use of devices, transmission paths, and signaling systems. The needs on information transmission utilizing power distribution equipment include stable power supply, diverse user services, and assurance of energy security. 2 figs.

  5. High-power ICRF and ICRF plus neutral-beam heating on PLT

    PLT ICRF experiments with RF powers up to approx.=3 MW have demonstrated efficient plasma heating in both the minority fundamental and the second harmonic ion-cyclotron regimes. In the minority 3He regime, ion temperatures of approx.=3 keV have been produced along with approx.=1 kW of D-3He fusion power and substantial electron heating. In the second harmonic H regime, an equivalent averaged ion energy of approx.=4 keV has been achieved. Combined ICRF plus neutral-beam heating experiments with auxiliary powers totalling up to 4.5 MW have provided insight into auxiliary heating performance at stored plasma energy levels up to approx.=100 kJ. Values of #betta#sub(phi) in the range of 1.5-2% have been attained for Bsub(phi) approx.=17 kG. Energetic discharges with n-barsub(e) up to approx.6x1013 cm-3 at Bsub(phi) approx.=28 kG have also been investigated. Preliminary confinement studies suggest that energetic ion losses may contribute to a direct loss of the input RF power in the H minority heating regime but are insignificant in the 3He minority case. The energy confinement time for the H minority regime is reduced somewhat from the Ohmic value. (author)

  6. Post-reconstruction full power and shut down level 2 PSA study for Unit 1 of Bohunice V1 NPP

    The level 2 PSA model of the J. Bohunice V1 NPP was developed in the RISK SPECTRUM Professional code with the following objectives: to identify the ways in which radioactive releases from the plant can occur following the core damage; to calculate the magnitudes and frequency of the release; to provide insights into the plant behaviour during a severe accident; to provide a framework for understanding containment failure modes; the impact of the phenomena that could occur during and following core damage and have the potential to challenge the integrity of the confinement; to support the severe accident management and development of SAMGs. The magnitudes of release categories are calculated using: the MAAP4/VVER for reactor operation and shutdown mode with closed reactor vessel and the MELCOR code for shutdown mode with open reactor vessel. In this paper an overview of the Level 2 PSA methodology; description of the confinement; the interface between the level 1 and 2 PSA and accident progression analyses are presented. An evaluation of the confinement failure modes and construction of the confinement event trees as well as definition of release categories, source term analysis and sensitivity analyses are also discussed. The presented results indicate that: 1)for the full power operation - there is an 25% probability that the confinement will successfully maintain its integrity and prevent an uncontrolled fission product release; the most likely mode of release from the confinement is a confinement bypass after SGTM with conditional probability of 30%; the conditional probability for the confinement isolation failure probability without spray is 5%, for early confinement failure at the vessel failure is 4%, for other categories 1% or less; 2) for the shutdown operating modes - the shutdown risk is high for the open reactor vessel and open confinement; important severe accident sequences exists for release categories: RC5.1, RC5.2 and RC6.2

  7. A selective separation method for 93Zr in radiochemical analysis of low and intermediate level wastes from nuclear power plants

    The zirconium isotope 93Zr is a long-lived pure β-particle-emitting radionuclide produced from 235U fission and from neutron activation of the stable isotope 92Zr and thus occurring as one of the radionuclides found in nuclear reactors. Due to its long half life, 93Zr is one of the radionuclides of interest for the performance of assessment studies of waste storage or disposal. Measurement of 93Zr is difficult owing to its trace level concentration and its low activity in nuclear wastes and further because its certified standards are not frequently available. A radiochemical procedure based on liquid-liquid extraction with 1-(2-thenoyl)-3,3,3-trifluoroacetone in xylene, ion exchange with Dowex resin and selective extraction using TRU resin has to be carried out in order to separate zirconium from the matrix and to analyze it by liquid scintillation spectrometry technique (LSC). To set up the radiochemical separation procedure for 93Zr, a tracer solution of 95Zr was used in order to follow the behavior of zirconium during the process by γ-ray spectrometry through measurement of the 95Zr. Then, the protocol was applied to low level waste (LLW) and intermediate level waste (ILW) from nuclear power plants. The efficiency detection for 63Ni was used to determination of 93Zr activity in the matrices analyzed. The limit of detection of the 0.05 Bq l-1 was obtained for 63Ni standard solutions by using a sample:cocktail ratio of 3:17 mL for OptiPhase HiSafe 3 cocktail. (author)

  8. Improved sampling and analytical techniques for characterization of very-low-level radwaste materials from commercial nuclear power stations

    Robertson, D.E. [Pacific Northwest Labs., Richland, WA (United States); Robinson, P.J. [Electric Power Research Inst., Palo Alto, CA (United States)

    1989-11-01

    This paper summarizes the unique sampling methods that were utilized in a recently completed project sponsored by the Electric Power Research Institute (EPRI) to perform accurate and precise radiological characterizations of several very-low-level radwaste materials from commercial nuclear power stations. The waste types characterized during this project included dry active waste (DAW), oil, secondary-side ion exchange resin, and soil. Special precautions were taken to insure representative sampling of the DAW. This involved the initial direct, quantitative gamma spectrometric analyses of bulk quantities (208-liter drums) of DAW utilizing a specially constructed barrel scanner employing a collimated intrinsic germanium detector assembly. Subsamples of the DAW for destructive radiochemical analyses of the difficult-to-measure 10CF61 radionuclides were then selected which had the same isotopic composition (to within {+-}25%) as that measured for the entire drum of DAW. The techniques for accomplishing this sampling are described. Oil samples were collected from the top, middle and bottom sections of 208-liter drums for radiochemical analyses. These samples were composited to represent the entire drum of oil. The accuracy of this type of sampling was evaluated by comparisons with direct, quantitative assays of a number of the drums using the barrel scanning gamma-ray spectrometer. The accuracy of sampling drums of spent secondary-side ion exchange resin was evaluated by comparing the radionuclide contents of grab samples taken from the tops of the drums with direct assays performed with the barrel scanner. The results of these sampling evaluations indicated that the sampling methods used were generally adequate for providing a reasonably representative subsample from bulk quantities of DAW, oil, and resin. The study also identified a number of potential pitfalls, in sampling of these materials.

  9. Procedures for conducting probabilistic safety assessments of nuclear power plants (level 2). Accident progression, containment analysis and estimation of accident source terms

    The present publication on Level 2 PSA is based on a compilation and review of practices in various Member States. It complements Safety Series No. 50-P-4, issued in 1992, on Procedures for Conducting Probabilistic Safety Assessments of Nuclear Power Plants (Level 1). Refs, figs and tabs

  10. Latent heat augmentation of thermocline energy storage for concentrating solar power – A system-level assessment

    Highlights: • We develop a new PCM-filled thermocline tank model to assess storage behavior. • A parametric study of PCM melting temperature and heat of fusion is performed. • Tanks filled with a single PCM do not provide benefit over baseline rock filler. • A cascaded PCM structure boosts energy density with suitable melt temperatures. - Abstract: Molten-salt thermocline tanks are a low-cost energy storage option for concentrating solar power plants. Despite the potential economic advantage, the capacity of thermocline tanks to store sufficient amounts of high-temperature heat is limited by the low energy density of the constituent sensible-heat storage media. A promising design modification replaces conventional rock filler inside the tank with an encapsulated phase-change material (PCM), contributing a latent heat storage mechanism to increase the overall energy density. The current study presents a new finite-volume approach to simulate mass and energy transport inside a latent heat thermocline tank at low computational cost. This storage model is then integrated into a system-level model of a molten-salt power tower plant to inform tank operation with respect to realistic solar collection and power production. With this system model, PCMs with different melting temperatures and heats of fusion are evaluated for their viability in latent heat storage for solar plants. Thermocline tanks filled with a single PCM do not yield a substantial increase in annual storage or plant output over a conventional rock-filled tank of equal size. As the melting temperature and heat of fusion are increased, the ability of the PCM to support steam generation improves but the corresponding ability of the thermocline tank to utilize this available latent heat decreases. This trend results from an inherent deconstruction of the heat-exchange region inside the tank between sensible and latent heat transfer, preventing effective use of the added phase change for daily plant

  11. THE RELATIONSHIP BETWEEN AEROBIC POWER AND REPEATED SPRINT ABILITY IN YOUNG SOCCER PLAYERS WITH DIFFERENT LEVELS OF VO2 MAX

    Rostam Alizadeh

    2010-06-01

    Full Text Available In some team sports such as soccer which is interval, athletes need to prepare themselves immediatelyfor the next activity. Therefore it is very important to have enough information on characteristics of recovery phase and quick recovery to the first situation and to have the minimum speed reduction. The purpose of this study was to determine the relationship between aerobic power and repeated sprint ability (RSA or decrementindex in young soccer players in three different levels of Vo2max. Methods: For this reason 41 volunteers were divided in to three groups with different levels of Vo2max ml.kg-1.min-1 low 37.22 ± 2.3 (n= 18, age 17.1 ± 0.9 year, height 170.6 ± 0.76 cm, weight 67.1 ± 5.05 kg medium 46.46± 1.97 ml.kg-1.min-1 (n= 13, age 17.6± 0.76year, height 173.8 ± 4.84 cm, weight 65.9 ± 4.92 kg and high 55.63 ± 1.52 ml.kg-1.min-1 (n=10, age 17.4 ±0.69 year, height 177 ± 3.23 cm, weight 71.4 ± 3.94 kg. To determine Vo2max a graded exercise test until volitional exhaustion on treadmill was used, and also RAST was used to measure RSA. The lactate accumulation was measured before and after RSA protocol. Pearson's correlation was used to determine the correlation between the aerobic power and RSA. The results indicated that there are significant relationship between Vo2max anddecremental index in low Vo2max group (r= 0.86, p= 0.001, no significant relationship medium Vo2max group (r= 0.14, p= 0.63 and negative significant relationship in high Vo2max group (r= - 0.64, p= 0.04. There are no significant relationship between Lactate accumulation and decremental index in medium (r= 0.005, p= 0.98 and high Vo2max groups (r=0.27, p= 0.45. Discussion: It is possible that the recovery of inter muscular resources relates to aerobic ability, but there are other factors effective in RSA rather than Vo2max and Lactate accumulation. The current study showed a normal curved relationship between Vo2max and RSA.

  12. Modernization of the feedwater heaters control level of the Almaraz I Nuclear Power Plant by OVATION system

    As a result of the process of technological renovation of the heaters system and the power increase project, Almaraz Nuclear Power Plant has made several design changes in the feedwater heaters system. Within these changes, the old heaters control loops are replaced because the new power will increase the heaters drainage caudal. This modernization is carried out using the OVATION control system.

  13. Power calibrations for TRIGA reactors

    The purpose of this paper is to establish a framework for the calorimetric power calibration of TRIGA reactors so that reliable results can be obtained with a precision better than ± 5%. Careful application of the same procedures has produced power calibration results that have been reproducible to ± 1.5%. The procedures are equally applicable to the Mark I, Mark II and Mark III reactors as well as to reactors having much larger reactor tanks and to TRIGA reactors capable of forced cooling up to 3 MW in some cases and 15 MW in another case. In the case of forced cooled TRIGA reactors, the calorimetric power calibration is applicable in the natural convection mode for these reactors using exactly the same procedures as are discussed below for the smaller TRIGA reactors (< 2 MW)

  14. Feedback circuit design of an auto-gating power supply for low-light-level image intensifier

    Yang, Ye; Yan, Bo; Zhi, Qiang; Ni, Xiao-bing; Li, Jun-guo; Wang, Yu; Yao, Ze

    2015-11-01

    This paper introduces the basic principle of auto-gating power supply which using a hybrid automatic brightness control scheme. By the analysis of current as image intensifier to special requirements of auto-gating power supply, a feedback circuit of the auto-gating power supply is analyzed. Find out the reason of the screen flash after the auto-gating power supply assembled image intensifier. This paper designed a feedback circuit which can shorten the response time of auto-gating power supply and improve screen slight flicker phenomenon which the human eye can distinguish under the high intensity of illumination.

  15. Power and area efficient 4-bit column-level ADC in a CMOS pixel sensor for the ILD vertex detector

    Zhang, L.; Morel, F.; Hu-Guo, Ch; Hu, Y.

    2013-01-01

    A 48 × 64 pixels prototype CMOS pixel sensor (CPS) integrated with 4-bit column-level, self triggered ADCs for the outer layers of the ILD vertex detector (VTX) was developed and fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. The pixel concept combines in-pixel amplification with a correlated double sampling (CDS) operation. The ADCs accommodating the pixel read out in a rolling shutter mode complete the conversion by performing a multi-bit/step approximation. The design was optimised for power saving at sampling frequency. The prototype sensor is currently at the stage of being started testing and evaluation. So what is described is based on post simulation results rather than test data. This 4-bit ADC dissipates, at a 3-V supply and 6.25-MS/s sampling rate, 486 μW in its inactive mode, which is by far the most frequent. This value rises to 714 μW in case of the active mode. Its footprint amounts to 35 × 545 μm2.

  16. Power and area efficient 4-bit column-level ADC in a CMOS pixel sensor for the ILD vertex detector

    A 48 × 64 pixels prototype CMOS pixel sensor (CPS) integrated with 4-bit column-level, self triggered ADCs for the outer layers of the ILD vertex detector (VTX) was developed and fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. The pixel concept combines in-pixel amplification with a correlated double sampling (CDS) operation. The ADCs accommodating the pixel read out in a rolling shutter mode complete the conversion by performing a multi-bit/step approximation. The design was optimised for power saving at sampling frequency. The prototype sensor is currently at the stage of being started testing and evaluation. So what is described is based on post simulation results rather than test data. This 4-bit ADC dissipates, at a 3-V supply and 6.25-MS/s sampling rate, 486 μW in its inactive mode, which is by far the most frequent. This value rises to 714 μW in case of the active mode. Its footprint amounts to 35 × 545 μm2.

  17. Predictive Current Control of a 7-level AC-DC back-to-back Converter for Universal and Flexible Power Management System

    Bifaretti, Steffano; Zanchetta, Pericle; Iov, Florin;

    2008-01-01

    The paper proposes a novel power conversion system for Universal and Flexible Power Management (UNIFLEX-PM) in Future Electricity Network. Its structure is based on a back-to-back three-phase AC-DC 7-level converter; each AC side is connected to a different PCC, representing the main grid and/or ...... numerous network conditions such as voltage unbalance, frequency excursions and harmonic distortion....

  18. Power Capability Investigation Based on Electrothermal Models of Press-pack IGBT Three-Level NPC and ANPC VSCs for Multimegawatt Wind Turbines

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig;

    2012-01-01

    addressed in this study for the three-level neutral-point-clamped voltage source converter (3L-NPC-VSC) and 3L Active NPC VSC (3L-ANPC-VSC) with press-pack insulated gate bipolar transistors employed as a grid-side converter. In order to investigate these VSCs' power capabilities under various operating...... conditions with respect to these limiting factors, a power capability generation algorithm based on the converter electrothermal model is developed. Built considering the VSCs' operation principles and physical structure, the model is validated by a 2 MV·A single-phase 3L-ANPC-VSC test setup. The power...

  19. Hand reach star excursion balance and power tests: do they predict overhead throwing performance of elite level female handball players?

    Sæland, Fredrik Oksum

    2015-01-01

    Background: Throwing performance is an important factor for scoring goals in handball. Mobility and power are two physical factors considered to be important for producing high ball speed. Evidence in the literature for a relationship between mobility tests and throwing performance, and power tests and throwing performance, are scarce and variable. One explanation for the variable and poor relationship to throwing performance could be that the conventional mobility and power te...

  20. "How much is enough?" Determining adequate levels of environmental compensation for wind power impacts using equivalency analysis

    Cole, Scott

    2009-01-01

    Environmental considerations at wind power developments require avoidance and mitigation of environmental impacts through proper citing, operational constraints, etc. However, some impacts are unavoidable for otherwise socially-beneficial projects. Criteria for Environmental Impact Assessment (EIA) suggest that compensation be provided for unavoidable or residual impacts on species and/or habitat from wind power development. Current environmental compensation schemes for wind power fail to de...

  1. Near-Field Acoustic Power Level Analysis of F31/A31 Open Rotor Model at Simulated Cruise Conditions, Technical Report II

    Sree, Dave

    2015-01-01

    Near-field acoustic power level analysis of F31A31 open rotor model has been performed to determine its noise characteristics at simulated cruise flight conditions. The non-proprietary parts of the test data obtained from experiments in the 8x6 supersonic wind tunnel were provided by NASA-Glenn Research Center. The tone and broadband components of total noise have been separated from raw test data by using a new data analysis tool. Results in terms of sound pressure levels, acoustic power levels, and their variations with rotor speed, freestream Mach number, and input shaft power, with different blade-pitch setting angles at simulated cruise flight conditions, are presented and discussed. Empirical equations relating models acoustic power level and input shaft power have been developed. The near-field acoustic efficiency of the model at simulated cruise conditions is also determined. It is hoped that the results presented in this work will serve as a database for comparison and improvement of other open rotor blade designs and also for validating open rotor noise prediction codes.

  2. (14)C levels in the vicinity of the Fukushima Dai-ichi Nuclear Power Plant prior to the 2011 accident.

    Xu, Sheng; Cook, Gordon T; Cresswell, Alan J; Dunbar, Elaine; Freeman, Stewart P H T; Hastie, Helen; Hou, Xiaolin; Jacobsson, Piotr; Naysmith, Philip; Sanderson, David C W; Tripney, Brian G; Yamaguchi, Katsuhiko

    2016-06-01

    A 50-year-old Japanese cedar (Cryptomeria japonica) from Okuma, ∼1 km southwest of the Fukushima Dai-ichi Nuclear Power Plant, was cored and each annual ring was analysed for (14)C. The (14)C specific activity values varied from 330.4 Bq kg(-1) C in the tree ring formed in 1971 to 231.2 Bq kg(-1) C in the 2014 ring. During the periods 1971-1976 and 2011-2014, the (14)C specific activities are indistinguishable from the ambient background values. However, compared with the ambient atmospheric levels, the (14)C specific activities between 1977 and 2010 are significantly elevated, clearly indicating (14)C discharges from the reactors during their normal operations. In addition, the specific activities are positively correlated with the annual electricity generation values. The excess (14)C specific activities were <36 Bq kg(-1) C, corresponding to an additional annual effective dose of <2 μSv via the food ingestion pathway in the study location. The primary wind direction is east-southeast/southeast with a frequency of ∼30%, in comparison to ∼20% frequency for the direction of the site under study (north-northeast/northeast). This would tend to indicate a similar magnitude of additional effective dose and consequently no significant radiological impact of atmospheric (14)C discharges from the FDNPP during the entire period of normal operations. Additionally, no (14)C pulse in activity can be observed in the year 2011 ring. This might be caused by a limited (14)C release from the damaged reactors during the accident or that the prevailing wind during the short period of release (11th-25th March 2011) was not in the direction of Okuma. PMID:27023156

  3. The democratisation of nuclear power policy in Japan; Focusing on strategies for geological disposal of high-level radioactive waste

    As public opposition is seen as the main factor prohibiting siting of high level waste repositories, we address the underlying causes of public opposition in Japan and the current measures being taken by the government and industry to address these issues. Furthermore, this lack of siting in turn raises questions concerning the future of nuclear power as an energy source and accompanying fuel cycle issues. This paper describes the conduct and results of the hearing sessions and their influence on the final recommendations. We also describe the progress of the recent efforts. Furthermore, the Atomic Energy Commission of Japan (AECJ) has founded another committee to integrate the public's views in forming the new body for the implementation of the disposal action plan. The main institutions or parties involved in nuclear energy policy in Japan include the AECJ, which promotes the development of nuclear energy; the Nuclear Safety Commission (NSC), which is responsible for the safety; Science and Technology Agency (STA), which provides support work and analysis for the NSC and AECJ; Ministry for International Trade and Industry (MITI) which is responsible for overall energy policy; the utilities and industry, local governments, anti-nuclear groups and the media. After the accident at Monju, three governors of nuclear plant concentrated prefectures wrote a letter of protest to the national government stating that they would not support the government energy strategy without public consensus building. They also called for greater efforts by the national government's energy policy to ensure safety. In the spring of 1996, the government, through the oversight of the AECJ, began a series of round table discussions. Prior to these meetings, policy making had ended with the input of the experts; the government is now making a serious attempt to integrate the public in the policy process. The attempt has been particularly evident in the policy-making process regarding the

  4. Large power supply facilities for fusion research

    The authors had opportunities to manufacture and to operate two power supply facilities, that is, 125MVA computer controlled AC generator with a fly wheel for JIPP-T-2 stellerator in Institute of Plasma Physics, Nagoya University and 3MW trial superconductive homopolar DC generator to the Japan Society for Promotion of Machine Industry. The 125MVA fly-wheel generator can feed both 60MW (6kV x 10kA) DC power for toroidal coils and 20MW (0.5kV x 40kA) DC power for helical coils. The characteristic features are possibility of Bung-Bung control based on Pontrjagin's maximum principle, constant current control or constant voltage control for load coils, and cpu control for routine operation. The 3MW (150V-20000A) homopolar generator is the largest in the world as superconductive one, however, this capacity is not enough for nuclear fusion research. The problems of power supply facilities for large Tokamak devices are discussed

  5. Power Analysis to Detect the Effects of a Continuous Moderator in 2-Level Simple Cluster Random Assignment Experiments

    Dong, Nianbo

    2014-01-01

    For intervention studies involving binary treatment variables, procedures for power analysis have been worked out and computerized estimation tools are generally available. The purpose of this study is to: (1) develop the statistical formulations for calculating statistical power, minimum detectable effect size (MDES) and its confidence interval,…

  6. Effect of variable power levels on the yield of total aerosol mass and formation of aldehydes in e-cigarette aerosols.

    Gillman, I G; Kistler, K A; Stewart, E W; Paolantonio, A R

    2016-03-01

    The study objective was to determine the effect of variable power applied to the atomizer of refillable tank based e-cigarette (EC) devices. Five different devices were evaluated, each at four power levels. Aerosol yield results are reported for each set of 25 EC puffs, as mass/puff, and normalized for the power applied to the coil, in mass/watt. The range of aerosol produced on a per puff basis ranged from 1.5 to 28 mg, and, normalized for power applied to the coil, ranged from 0.27 to 1.1 mg/watt. Aerosol samples were also analyzed for the production of formaldehyde, acetaldehyde, and acrolein, as DNPH derivatives, at each power level. When reported on mass basis, three of the devices showed an increase in total aldehyde yield with increasing power applied to the coil, while two of the devices showed the opposite trend. The mass of formaldehyde, acetaldehyde, and acrolein produced per gram of total aerosol produced ranged from 0.01 to 7.3 mg/g, 0.006 to 5.8 mg/g, and aerosols from specific devices, and were compared to estimated exposure from consumption of cigarettes, to occupational and workplace limits, and to previously reported results from other researchers. PMID:26743740

  7. Themis - A solar power station

    Hillairet, J.

    The organization, goals, equipment, costs, and performance of the French Themis (Thermo-helio-electric-MW) project are outlined. The program was begun for both the domestic energy market and for export. The installation comprises a molten eutectic salt loop which receives heat from radiators situated in a central tower. The salt transfers the heat to water for steam generation of electricity. A storage tank holds enough molten salt to supply one day's reserve of power, 40 MWh. A field of heliostats directs the suns rays for an estimated 2400 hr/yr onto the central receiver aperture, while 11 additional parabolic concentrators provide sufficient heat to keep the salt reservoir at temperatures exceeding 200 C. In a test run of several months during the spring of 1982 the heliostats directed the sun's rays with an average efficiency of 75 percent, yielding 2.3 MW of power at a system efficiency of 20.5 percent in completely automatic operation.

  8. Clearance level (de minimis) : examples of difficulties met in the nuclear power plants of EDF about the very low level active waste management

    The absence of a clear reglementation concerning very low radioactive waste management has led EDF to harmonise its internal practices. However plant operators are still confronted with many difficulties for: very low radioactive waste which have really been contaminated; very low radioactive waste whose radioactivity is not due to on a site nuclear practices (natural radioactivity of off-site artificial radioactivity); waste which is suspected to be contaminated simply because it has transited through a nuclear power plant even outside of all controlled areas. (author)

  9. The neutron flux redistribution effects on the power level reading from the nuclear detectors in a research reactor

    Thermal power calibration of the nuclear instrumentation in the TRIGA reactor in Ljubljana is described. To correct for the position of the control rods, perturbation factors are introduced and the procedures to measure them are described. The use of the perturbation factors is shown to enable power readings from the nuclear instrumentation with an accuracy better than 2% standard deviation. This is a significant improvement compared to the case without corrections, where the displayed power can vary by as much as 30% in the most unfavourable case. (author)

  10. An radiotoxicity evaluation of high level wastes for a scenery of Brazilian Nuclear Power Plants in accordance with the Energy Expansion Brazilian Plan 2030

    This paper is a part of the author scientific initiation, and makes an evaluation of the radiotoxicity which would be produced by the Brazilian nuclear power plants in a scenery of 7 power plants operating in 2030, in according to the official expansion plans which point out the additional introduction of 4000 MW(e), or 4 ne power plant additionally to the Angra I, II and III. Considering that all reactors would be a PWR reactors. The calculated parameter was the relative toxicity of the low and intermediate level nuclear wastes (LLPP - long lived fission products and HLW - high level waste related to the radiotoxicity of natural uranium versus time. All the calculation used the ORIGEN-S code. (author)

  11. Loss and thermal redistributed modulation methods for three-level neutral-point-clamped wind power inverter undergoing Low Voltage Ride Through

    Ma, Ke; Blaabjerg, Frede

    2012-01-01

    investigates the loss and thermal performances of a 10 MW 3L-NPC wind power inverter undergoing Low Voltage Ride Through (LVRT) operation. A series of new space vector modulation methods are then proposed to relocate the thermal loading among the power switching devices. It is concluded that, with the proposed......The three-level neutral-point-clamped (3L-NPC) converter is a promising multilevel topology in the application of mega-watts wind power generation system. However, the growing requirements by grid codes may impose high stress and even give reliability problem to this converter topology. This paper...... modulation methods, the thermal distribution in the 3L-NPC wind power inverter undergoing LVRT becomes more equal, and the junction temperature of the most stressed devices can be also relieved. Also the control ability of DC-bus neutral point potential, which is one of the crucial considerations for the 3L...

  12. Converter Structure-Based Power Loss and Static Thermal Modeling of The Press-Pack IGBT Three-Level ANPC VSC Applied to Multi-MW Wind Turbines

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig;

    2011-01-01

    performance, the converter structure-based power loss and thermal models are developed in this study for the medium-voltage (MV) three-level active neutral-point-clamped voltage source converter (3L-ANPC-VSC) utilizing 4500 V-1800 A press-pack insulated-gate bipolar transistor-diode pairs and interfacing a 6...

  13. The discriminative power of the Interval Shuttle Run Test and the Maximal Multistage Shuttle Run Test for playing level of soccer

    Lemmink, K.A.P.M.; Verheijen, R.; Visscher, C.

    2004-01-01

    AIM: The purpose of this study was to examine the discriminative power of the recently developed Interval Shuttle Run Test (ISRT) and the widely used Maximal Multistage 20 m Shuttle Run Test (MMSRT) for soccer players at different levels of competition. The main difference between the tests is that

  14. Wind power in power systems

    Ackermann, Thomas

    2012-01-01

    The second edition of the highly acclaimed Wind Power in Power Systems has been thoroughly revised and expanded to reflect the latest challenges associated with increasing wind power penetration levels. Since its first release, practical experiences with high wind power penetration levels have significantly increased. This book presents an overview of the lessons learned in integrating wind power into power systems and provides an outlook of the relevant issues and solutions to allow even higher wind power penetration levels. This includes the development of standard wind turbine sim

  15. The impact of power market reforms on electricity price-cost margins and cross-subsidy levels: A cross country panel data analysis

    One of the main expectations from power market reform has been a reduction in both price-cost margins and cross-subsidy levels between industrial and residential consumers. This paper focuses on this issue by looking at the impact of the electricity industry reforms on residential and industrial electricity price-cost margins and their effect on cross-subsidy levels between consumer groups. Using panel data for 63 developed and developing countries covering the period 1982-2009, empirical models are developed and analyzed. The research findings suggest that there is no uniform pattern for the impact of reform process as a whole on price-cost margins and cross-subsidy levels. Each individual reform step has different impact on price-cost margins and cross-subsidy levels for each consumer and country group. Our findings imply that reform steps have different impacts in different countries, which supports the idea reform prescription for a specific country cannot easily and successfully be transferred to another one. So, transferring the formal and economic structure of a successful power market in a developed country to developing countries is not a sufficient condition for good economic performance of the electricity industries in developing countries. Furthermore, the study suggests that power consumption, income level and country-specific features constitute other important determinants of electricity price-cost margins and cross-subsidy levels. - Research highlights: → The paper focuses on the impact of power market reforms on price-cost margins and cross-subsidy levels. → Using panel data for 63 countries for the period 1982-2009, empirical models are developed and analyzed. → We found that each individual reform step has different impact for each consumer and country group. → We conclude that reform prescription for a specific country cannot easily be transferred to another one.

  16. Parque fotovoltaico en Xerta de 1,3 MW

    Romera Romero, Jose Manuel

    2010-01-01

    El presente proyecto tiene por objeto el diseño e implantación de un Parque Fotovoltaico, el cual se ubicará en la parcela 308, en el término municipal de Xerta en la comarca del Baix Ebre y tendrá una superficie de 24.471 m² aproximadamente y orientada al Sur. El Parque Fotovoltaico aprovechara una fuente de energía renovable e inagotable como son los rayos del sol, para producir energía eléctrica. Este estará conectado a la red eléctrica existente y la conexión se realizará e...

  17. Replacement of the level control of draining tanks MSRS and powered water heaters with the OVATION system in Asco NPP

    The current MSR drains and heaters tanks level control is local control individual, pneumatic and without action from Control room. The system has level switches for the generation of alarms, isolations and shots of bombs. Single control room operators have level alarms, final race of valves of control and indication of temperature and pressure of some tanks.

  18. Power level control of the TRIGA Mark-II research reactor using the multifeedback layer neural network and the particle swarm optimization

    Highlights: • A multifeedback-layer neural network controller is presented for a research reactor. • Off-line learning of the MFLNN is accomplished by the PSO algorithm. • The results revealed that the MFLNN–PSO controller has a remarkable performance. - Abstract: In this paper, an artificial neural network controller is presented using the Multifeedback-Layer Neural Network (MFLNN), which is a recently proposed recurrent neural network, for neutronic power level control of a nuclear research reactor. Off-line learning of the MFLNN is accomplished by the Particle Swarm Optimization (PSO) algorithm. The MFLNN-PSO controller design is based on a nonlinear model of the TRIGA Mark-II research reactor. The learning and the test processes are implemented by means of a computer program at different power levels. The simulation results obtained reveal that the MFLNN-PSO controller has a remarkable performance on the neutronic power level control of the reactor for tracking the step reference power trajectories

  19. Multi-level distributed microprocessor system for a nuclear power plant fire protection system controls, monitoring and communication

    All nuclear power plants must have fire monitoring and fire suppression systems. The design, construction and operation of these systems involve considerable skill and considerable cost. The instrumentation and control requirements are extensive and sophisticated. Adequate reference works for these requirements and how to achieve them are not available. This paper is an attempt to describe these instrumentation and control requirements and also to present a specific design concept. This incorporates the result of the writer's experience in working with the design review and commissioning the instrumentation and controls of the entire fire detection and suppression system in an operational nuclear power plant and his subsequent study on the subject. 13 refs

  20. Application of local computer networks to nuclear power plant problems at the level of automated control of the production process

    The requirements placed on the hardware and software for the automated system of production control at a nuclear power plant are summarized. In the design of the Temelin nuclear power plant, this system is local network-based, with two-way communication between the local stations. The control functions are distributed among 6 local stations, viz. the file server, interactive terminal, information terminal, data storage terminal, calculation terminal and communication terminal. A brief characterization is given of the necessary software, including both the system software and the basic and applications user software. (Z.M.)

  1. Estimation of an Effective Young’s Modulus of Elasticity in the Locality of the Gabčíkovo Hydrology Power Plant by Geometric Leveling

    Mojzeš Marcel; Kollár Pavol; Mikolaj Michal

    2015-01-01

    The Gabčíkovo hydroelectric power plant is located in a complicated geological environment (gravel sub-soil and a high groundwater level). Excavation work started after the withdrawal of water in the autumn of 1984 and lasted until the autumn of 1986. A basic geodetic control network with a special monument was founded before the excavation work began. This network served for the setting-out of the hydroelectric power plant as well as for the control of the excavation work. The repeated geode...

  2. Influence of the level of fit of a density probability function to wind-speed data on the WECS mean power output estimation

    Carta, Jose A. [Department of Mechanical Engineering, University of Las Palmas de Gran Canaria, Campus de Tafira s/n, 35017 Las Palmas de Gran Canaria, Canary Islands (Spain); Ramirez, Penelope; Velazquez, Sergio [Department of Renewable Energies, Technological Institute of the Canary Islands, Pozo Izquierdo Beach s/n, 35119 Santa Lucia, Gran Canaria, Canary Islands (Spain)

    2008-10-15

    Static methods which are based on statistical techniques to estimate the mean power output of a WECS (wind energy conversion system) have been widely employed in the scientific literature related to wind energy. In the static method which we use in this paper, for a given wind regime probability distribution function and a known WECS power curve, the mean power output of a WECS is obtained by resolving the integral, usually using numerical evaluation techniques, of the product of these two functions. In this paper an analysis is made of the influence of the level of fit between an empirical probability density function of a sample of wind speeds and the probability density function of the adjusted theoretical model on the relative error {epsilon} made in the estimation of the mean annual power output of a WECS. The mean power output calculated through the use of a quasi-dynamic or chronological method, that is to say using time-series of wind speed data and the power versus wind speed characteristic of the wind turbine, serves as the reference. The suitability of the distributions is judged from the adjusted R{sup 2} statistic (R{sub a}{sup 2}). Hourly mean wind speeds recorded at 16 weather stations located in the Canarian Archipelago, an extensive catalogue of wind-speed probability models and two wind turbines of 330 and 800 kW rated power are used in this paper. Among the general conclusions obtained, the following can be pointed out: (a) that the R{sub a}{sup 2} statistic might be useful as an initial gross indicator of the relative error made in the mean annual power output estimation of a WECS when a probabilistic method is employed; (b) the relative errors tend to decrease, in accordance with a trend line defined by a second-order polynomial, as R{sub a}{sup 2} increases. (author)

  3. Influence of the level of fit of a density probability function to wind-speed data on the WECS mean power output estimation

    Static methods which are based on statistical techniques to estimate the mean power output of a WECS (wind energy conversion system) have been widely employed in the scientific literature related to wind energy. In the static method which we use in this paper, for a given wind regime probability distribution function and a known WECS power curve, the mean power output of a WECS is obtained by resolving the integral, usually using numerical evaluation techniques, of the product of these two functions. In this paper an analysis is made of the influence of the level of fit between an empirical probability density function of a sample of wind speeds and the probability density function of the adjusted theoretical model on the relative error ε made in the estimation of the mean annual power output of a WECS. The mean power output calculated through the use of a quasi-dynamic or chronological method, that is to say using time-series of wind speed data and the power versus wind speed characteristic of the wind turbine, serves as the reference. The suitability of the distributions is judged from the adjusted R2 statistic (Ra2). Hourly mean wind speeds recorded at 16 weather stations located in the Canarian Archipelago, an extensive catalogue of wind-speed probability models and two wind turbines of 330 and 800 kW rated power are used in this paper. Among the general conclusions obtained, the following can be pointed out: (a) that the Ra2 statistic might be useful as an initial gross indicator of the relative error made in the mean annual power output estimation of a WECS when a probabilistic method is employed; (b) the relative errors tend to decrease, in accordance with a trend line defined by a second-order polynomial, as Ra2 increases

  4. High-power and steady-state operation of ICRF heating in the large helical device

    Mutoh, T., E-mail: mutoh@nifs.ac.jp; Seki, T.; Saito, K.; Kasahara, H.; Seki, R.; Kamio, S.; Kumazawa, R.; Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Ii, T.; Makino, R.; Nagaoka, K.; Nomura, G. [National Institute for Fusion Science, 322-6, Oroshi-cho, Toki, Gifu, 509-5292 (Japan); Shinya, T. [The University of Tokyo, Kashiwa 2777-8561 (Japan)

    2015-12-10

    Recent progress in an ion cyclotron range of frequencies (ICRF) heating system and experiment results in a Large Helical Device (LHD) are reported. Three kinds of ICRF antenna pairs were installed in the LHD, and the operation power regimes were extended up to 4.5 MW; also, the steady-state operation was extended for more than 45 min in LHD at a MW power level. We studied ICRF heating physics in heliotron configuration using a Hand Shake type (HAS) antenna, Field Aligned Impedance Transforming (FAIT) antenna, and Poloidal Array (PA) antenna, and established the optimum minority-ion heating scenario in an LHD. The FAIT antenna having a novel impedance transformer inside the vacuum chamber could reduce the VSWR and successfully injected a higher power to plasma. We tested the PA antennas completely removing the Faraday-shield pipes to avoid breakdown and to increase the plasma coupling. The heating performance was almost the same as other antennas; however, the heating efficiency was degraded when the gap between the antenna and plasma surface was large. Using these three kinds of antennas, ICRF heating could contribute to raising the plasma beta with the second- and third-harmonic cyclotron heating mode, and also to raising the ion temperature as discharge cleaning tools. In 2014, steady-state operation plasma with a line-averaged electron density of 1.2 × 10{sup 19} m{sup −3}, ion and electron temperature of 2 keV, and plasma sustainment time of 48 min was achieved with ICH and ECH heating power of 1.2 MW for majority helium with minority hydrogen. In 2015, the higher-power steady-state operation with a heating power of up to 3 MW was tested with higher density of 3 × 10{sup 19} m{sup −3}.

  5. High-power and steady-state operation of ICRF heating in the large helical device

    Recent progress in an ion cyclotron range of frequencies (ICRF) heating system and experiment results in a Large Helical Device (LHD) are reported. Three kinds of ICRF antenna pairs were installed in the LHD, and the operation power regimes were extended up to 4.5 MW; also, the steady-state operation was extended for more than 45 min in LHD at a MW power level. We studied ICRF heating physics in heliotron configuration using a Hand Shake type (HAS) antenna, Field Aligned Impedance Transforming (FAIT) antenna, and Poloidal Array (PA) antenna, and established the optimum minority-ion heating scenario in an LHD. The FAIT antenna having a novel impedance transformer inside the vacuum chamber could reduce the VSWR and successfully injected a higher power to plasma. We tested the PA antennas completely removing the Faraday-shield pipes to avoid breakdown and to increase the plasma coupling. The heating performance was almost the same as other antennas; however, the heating efficiency was degraded when the gap between the antenna and plasma surface was large. Using these three kinds of antennas, ICRF heating could contribute to raising the plasma beta with the second- and third-harmonic cyclotron heating mode, and also to raising the ion temperature as discharge cleaning tools. In 2014, steady-state operation plasma with a line-averaged electron density of 1.2 × 1019 m−3, ion and electron temperature of 2 keV, and plasma sustainment time of 48 min was achieved with ICH and ECH heating power of 1.2 MW for majority helium with minority hydrogen. In 2015, the higher-power steady-state operation with a heating power of up to 3 MW was tested with higher density of 3 × 1019 m−3

  6. Levels of 137Cs and 40K in marine superficial sediments near the Angra Nuclear Power Plant (Angra dos Reis, SE Brazil)

    This study evaluated the spatial distribution of two environmentally relevant radionuclides, 137Cs and 40K, in marine superficial sediments around the Angra Nuclear Power Plant, the only Brazilian nuclear power plant complex, thus establishing a baseline for bottom sediments, given the international importance of environmental monitoring around nuclear facilities. It was observed that these radionuclides are mostly present in the muddy sediments as a result of their stronger association with its fine-grained fraction, and that their lowest levels are located around the liquid effluent discharge of the plant, as a consequence of the prevented deposition of fine sediments due to the strong discharge water flux. The comparison of the 137Cs activities in the region with other locations in the world showed that the presence of this artificial nuclide is due to the atmospheric fallout from past nuclear tests made during the Cold War, not to the nuclear power plant activities.

  7. Levels of {sup 137}Cs and {sup 40}K in marine superficial sediments near the Angra Nuclear Power Plant (Angra dos Reis, SE Brazil)

    Lima Ferreira, Paulo Alves de; Farina Amorim, Lais; Marone Tura, Pedro; Medeiros Zacheo, Valter Andre; Lopes Figueira, Rubens Cesar [Universidade de Sao Paulo (IO-USP), SP (Brazil). Inst. Oceanografico

    2015-07-01

    This study evaluated the spatial distribution of two environmentally relevant radionuclides, {sup 137}Cs and {sup 40}K, in marine superficial sediments around the Angra Nuclear Power Plant, the only Brazilian nuclear power plant complex, thus establishing a baseline for bottom sediments, given the international importance of environmental monitoring around nuclear facilities. It was observed that these radionuclides are mostly present in the muddy sediments as a result of their stronger association with its fine-grained fraction, and that their lowest levels are located around the liquid effluent discharge of the plant, as a consequence of the prevented deposition of fine sediments due to the strong discharge water flux. The comparison of the {sup 137}Cs activities in the region with other locations in the world showed that the presence of this artificial nuclide is due to the atmospheric fallout from past nuclear tests made during the Cold War, not to the nuclear power plant activities.

  8. Evaluation of training programs and entry-level qualifications for nuclear-power-plant control-room personnel based on the systems approach to training

    Haas, P M; Selby, D L; Hanley, M J; Mercer, R T

    1983-09-01

    This report summarizes results of research sponsored by the US Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research to initiate the use of the Systems Approach to Training in the evaluation of training programs and entry level qualifications for nuclear power plant (NPP) personnel. Variables (performance shaping factors) of potential importance to personnel selection and training are identified, and research to more rigorously define an operationally useful taxonomy of those variables is recommended. A high-level model of the Systems Approach to Training for use in the nuclear industry, which could serve as a model for NRC evaluation of industry programs, is presented. The model is consistent with current publically stated NRC policy, with the approach being followed by the Institute for Nuclear Power Operations, and with current training technology. Checklists to be used by NRC evaluators to assess training programs for NPP control-room personnel are proposed which are based on this model.

  9. Evaluation of training programs and entry-level qualifications for nuclear-power-plant control-room personnel based on the systems approach to training

    This report summarizes results of research sponsored by the US Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research to initiate the use of the Systems Approach to Training in the evaluation of training programs and entry level qualifications for nuclear power plant (NPP) personnel. Variables (performance shaping factors) of potential importance to personnel selection and training are identified, and research to more rigorously define an operationally useful taxonomy of those variables is recommended. A high-level model of the Systems Approach to Training for use in the nuclear industry, which could serve as a model for NRC evaluation of industry programs, is presented. The model is consistent with current publically stated NRC policy, with the approach being followed by the Institute for Nuclear Power Operations, and with current training technology. Checklists to be used by NRC evaluators to assess training programs for NPP control-room personnel are proposed which are based on this model

  10. Use of cost benefit analysis methodology in the meaning of motorization level from small and medium hydroelectric power plants

    The technical and economic justifications that bringing the waterfall division reformulation between Lucas Nogueira Garcez Plant and Capivara Plant in Paranapanema River (Brazil) are described, including a comparative economic of Canoas (Alta), Canoas I and Canoas II passages, motorization study and energetic benefits. The reasons of the Bulbo turbines choice and dimensioning definition of the installed power by the new reference economic parameters are also presented. (C.G.C.). 5 refs, 11 tabs

  11. Hydrostatic levelling of a NPP (Nuclear Power Plant) floor during the pressure test of the surrounding wall experimental measurement

    The stability of the floor of a nuclear Plant (NPP) is continuously checked with existing levelling systems. In January 1999, the NPP of Flamanville (North-West of France) which is not equipped with such a system, decided to carry out an experimental measurement with a 'Hydrostatic Leveling System' (HLS), during the pressure test (for inspection air-tightness) of the surrounding wall. This paper will describe the conception, the installation of such a system and the results of the measurement. It is shown that the hydrostatic levelling system allows measurement of deformations in real-time with a very high accuracy. (author)

  12. Price Level Convergence, Purchasing Power Parity and Multiple Structural Breaks in Panel Data Analysis: An Application to U.S. Cities

    Basher Syed A.; Carrion-i-Silvestre Josep Lluís

    2009-01-01

    This article provides a methodological and empirical approach for assessing price level convergence and its relation to purchasing power parity (PPP) using annual price data for seventeen U.S. cities during the period 1918 to 2005. We suggest a new panel data procedure that can handle a wide range of PPP concepts in the presence of multiple structural breaks using all possible pairs of real exchange rates. Testing for PPP requires the definition of parametric restrictions (parity restrictions...

  13. Declining LO-Confederation Membership and its Consequences on Power-Dependence Relation and Wage Levels in Two Danish Trade Unions

    Schjøttz, Frederik

    2014-01-01

    The scope of this semester assignment will assess the phenomenon and the causes of declining membership in LO confederation unions, the impact this could have on wage levels in Denmark and the effect on power-dependence relations between two trade unions and their respective employer unions. Having previously assessed recruitment strategies and motivations for recruitment of potential trade union members, I now wish to assess the phenomenon of the declining rate of memberships on a grande...

  14. Experimental RA reactor operation with 80% enriched fuel - Program of experimental operation: a) Program of experimental operation with 80% enriched fuel at low power, b) contents of the experimental operation with 80% enriched fuel at higher power levels

    Highly enriched (80%) uranium oxide fuel was regularly used in the mixed reactor core with the 2% enriched fuel since 1976. The most important changes related to reactor operation, in comparison with the original design project were related to reactor core fuelling schemes. At the end of 1979 reactor was shutdown due to the corrosion coating noticed on some fuel elements and due to decrease quality of the heavy water. Subsequently the Sanitary inspector of Serbia has prohibited further reactor operation. Restart of the reactor will not be a simple continuation of operation. It is indispensable to perform complete experimental program including measurements of critical parameters at different power levels for the core with fresh 80% enriched fuel. The aim of this document is to obtain working permission and its contents are in agreement with the procedure demanded by the Safety Committee of the Institute. It includes results of optimization and safety analysis for the initial reactor core. Since the permission for restart is not obtained, a separate RA reactor safety report is prepared in addition to the program for experimental operation. This report includes: detailed program for reactor experimental operation with 80% enriched fuel in the core at low power levels, and contents of the experimental operation with 80% enriched fuel in the core at higher power levels

  15. Power Balance Control in an AC/DC/AC Converter for Regenerative Braking in a Two-Voltage-Level Flywheel-Based Driveline

    Janaína G. Oliveira

    2011-01-01

    Full Text Available The integration of a flywheel as a power handling can increase the energy storage capacity and reduce the number of battery charge/discharge cycles. Furthermore, the ability of recovering energy of the vehicle during breaking can increase the system efficiency. The flywheel-based all-electric driveline investigated here has its novelty in the use of a double-wound flywheel motor/generator, which divides the system in two different voltage levels, enhancing the efficiency of the electric driveline. The connection of two AC electrical machines (i.e., the flywheel and the wheel motor with different and variable operation frequency is challenging. A power matching control applied to an AC/DC/AC converter has been implemented. The AC/DC/AC converter regenerates the electric power converted during braking to the flywheel machine, used here as power handling device. By controlling the power balance, the same hardware can be used for acceleration and braking, providing the reduction of harmonics and robust response. A simulation of the complete system during braking mode has been performed both in Matlab and Simulink, and their results have been compared. The functionality of the proposed control has been shown and discussed, with full regeneration achieved. A round-trip efficiency (wheel to wheel higher than 80% has been obtained.

  16. Energy matching and optimization analysis of waste to energy CCHP (combined cooling, heating and power) system with exergy and energy level

    CCHP (combined cooling, heating and power) system as a poly-generation technology has received an increasing attention in field of small scale power systems for applications ranging from residence to utilities. It will also play an important role in waste to energy application for megacities. However, how to evaluate and manage energy utilization of CCHP scientifically remains unclear. In this paper, energy level and exergy analysis are implemented on energy conversion processes to reveal the variation of energy amount and quality in the operation of CCHP system. Moreover, based on the energy level analysis, the methodology of energy matching and optimization for the CCHP system is proposed. By this method, the operational parameters of CCHP system can be deduced to obtain an efficient performance and proper energy utilization. It will be beneficial to understand and operate the CCHP system, and to provide a guiding principle of the energy conversion and management for the CCHP system. - Highlights: • Energy level is implemented to reveal the energy variation of CCHP system. • A mathematical energy level analysis model of CCHP system is proposed. • By energy level analysis between supply and demand, optimal zone is obtained. • This study will be useful for energy matching and optimization of CCHP system

  17. Design and experience with the BICOTH-type reactor water level gauge for the Dodewaard nuclear power plant

    An alternative system to measure operating water levels in the Netherland's Dodewaard BWR (200 MWt, natural circulation) was developed. Its design is based on BICOTH sensors that contain heater wires and multi-junction differential thermocouple wires. Binary codes are obtained that correspond uniquely to stable water levels present in a standpipe mounted to the inside of the reactor vessel wall. From the experiments, it was found that the additional use of the analog information contained in the temperature transition functions of the TC junctions results in very accurate and smooth water level indications. An advanced water level sensor named TRICOTH is proposed that is based on the design and operating experience with the present system

  18. Results of ECCS analysis and expedient based on them relevant to pressurizer level gauges in (2 or 3 loop) PWR nuclear power plants

    The Nuclear Safety Commission investigated the report dated July 17, 1979, submitted by the Special Committee on Examination of Reactor Safety on the results of ECCS analysis and the expedient based on them, relevant to pressurizer level gauges in (2 or 3 loop) PWR nuclear power plants other than Ohii power plant, concerning the problem of the pressurizer level gauges pointed out relating to the accident of the Three Mile Island No. 2 nuclear power plant in the United States. The Commission judged the above report reasonable. The contents of investigation include the propriety of determining the representative plant by selecting Ikata No. 1 or Takahama No. 1 plant, the propriety of the preconditions for safety analysis and analysis codes (use of MARVEL and SATAN codes), the results of safety analysis investigations and others. The propriety of maintaining the circuit of generating safe injection signal by the coincidence of the decrease of reactor pressure with the decrease of pressurizer level, the influence of adding the circuit for safe injection signal (P' circuit) which operates due to the abnormal decrease of reactor pressure on the past analysis for ECCS evaluation, and the effect of the block circuit added to the P' circuit are specifically reported in detail. (Wakatsuki, Y.)

  19. A new balancing three level three dimensional space vector modulation strategy for three level neutral point clamped four leg inverter based shunt active power filter controlling by nonlinear back stepping controllers.

    Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F

    2016-07-01

    In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK. PMID:27018144

  20. System-Level Power Optimization for a ΣΔ D/A Converter for Hearing-Aid Application

    Pracný, Peter; Jørgensen, Ivan Harald Holger; Bruun, Erik

    2013-01-01

    for audio applications we take the maximum gain of the modulator noise transfer function (NTF) as a design parameter. By increasing the maximum NTF gain the cutoff frequency of modulator loop filter is increased which lowers the in-band quantization noise but also lowers the maximum stable amplitude...... entire hearing-aid audio back-end system resulting in less hardware and power consumption in the interpolation filter, in the sigma-delta modulator and reduced switching rate of the Class D output stage....

  1. Detailed description of an SSAC at the facility level for on-load refueled power reactor facilities

    The purpose of this document is to provide a detailed description of a system for the accounting for and control of nuclear material in an on-load refueled power reactor facility which can be used by a facility operator to establish his own system to comply with a national system for nuclear material accounting and control and to facilitate application of IAEA safeguards. The scope of this document is limited to descriptions of the following SSAC elements: (1) Nuclear Material Measurements; (2) Measurement Quality; (3) Records and Reports; (4) Physical Inventory Taking; (5) Material Balance Closing

  2. Levels and patterns of polycyclic aromatic hydrocarbons in fly ash generated in Coal-fired power plant

    The burning of pulverized coal to produce energy for generation of electricity in thermal power plants results in huge quantity of coal ash of varying properties. Because of the increase in electricity production, the amount of ash produced will increase proportionally. A large percentage of coal fly ash is comprised of relatively inert materials, such as silica and other trace and toxic elements. The coal ash also contain organic constituents of potential environmental concern. So far, very few studies on characterization of organic constituents in fly ash have been reported in the literature. In the present study, the fly ashes generated from the power stations are investigated regarding the distribution of 14 PAHs. The total amount of PAHs in the fly ash samples varied between 45.8 ng/g and 257.7 ng/g. Lower molecular weight (MW) PAHs, were found to be predominant in the fly ash samples. The concentration of Benzo(a)pyrene, which is the most potent carcinogenic PAH was found to vary between 0.8 ng/g to 6.3 ng/g with a mean concentration of 2.5 ng/g. (author)

  3. Interpersonal Influence Process in Real Life Counseling: Investigating Client Perceptions, Counselor Experience Level, and Counselor Power over Time.

    Heppner, P. Paul; Heesacker, Martin

    1982-01-01

    Examined interpersonal influence processes within an actual counseling context over an average of eight sessions. Results indicated that counselor experience level did not affect client perceptions of the counselor and perceived counselor expertise, attractiveness, and trustworthiness did change over time, but not in the same direction. (Author)

  4. Foreign programs for the storage of spent nuclear power plant fuels, high-level waste canisters and transuranic wastes

    The various national programs for developing and applying technology for the interim storage of spent fuel, high-level radioactive waste, and TRU wastes are summarized. Primary emphasis of the report is on dry storage techniques for uranium dioxide fuels, but data are also provided concerning pool storage

  5. Effects of exercise in polluted air on the aerobic power, serum lactate level and cell blood count of active individuals

    Mehdi Kargarfard

    2011-01-01

    Conclusions: Exercise in high-polluted air resulted in a significant reduction in the performance at submaximal levels of physical exertion. Therefore, the acute exposure to polluted air may cause a significant reduction in the performance of active individuals. The clinical importance of these findings should be assessed in longitudinal studies.

  6. Detailed description of an SSAC at the facility level for light water moderated (off-load refueled) power reactor facilities

    This report is intended to provide the technical details of an effective State Systems of Accounting for and Control of Nuclear Material (SSAC) which Member States may use, if they wish, to establish and maintain their SSACs. It is expected that systems designed along the lines described would be effective in meeting the objectives of both national and international systems for nuclear material accounting and control. This document accordingly provides a detailed description of a system for the accounting for and control of nuclear material in an off-load refueled light water moderated power reactor facility which can be used by a facility operator to establish his own system to comply with a national system for nuclear material accounting and control and to facilitate application of IAEA safeguards. The scope of this document is limited to descriptions of the following elements: (1) Nuclear Material Measurements; (2) Measurement Quality; (3) Records and Reports; (4) Physical Inventory Taking; (5) Material Balance Closing

  7. The exergy and energy level analysis of a combined cooling, heating and power system driven by a small scale gas turbine at off design condition

    This paper presents the off design performance analysis of a combined cooling, heating, and power (CCHP) system consisting of a small-scale gas turbine, an exhaust-fired double-effect absorption chiller, and a heat exchanger. The energy and exergy analyses of the CCHP system are investigated under the rated and part-load conditions. Energy level analysis is implemented on the energy conversion processes to reveal the mechanisms of the deterioration of the CCHP performance under part-load conditions. The results show that the CCHP system is energy saving when the power output of the gas turbine exceeds 30% of the full load. It is also found that the CO2 emission of the CCHP system reduced by 66.7%–70.5%, compared with conventional separation system, when the power output of gas turbine increased from about 30% to 100%. Energy level results reveal that the combustor of the small-scale gas turbine mainly contributed to the deteriorated performance of the CCHP system. In addition, a case study is carried out to illustrate the advantage of using dynamic data in the performance assessment. The case results indicate that using off-design data leads to a more realistic evaluation of the CCHP system. - Highlights: •The design and off-design performance of a small-scale gas turbine is studied. •The design and off-design performance of an absorption chiller is studied. •An analysis module based on the concept of energy level is developed in this paper. •Energy level and exergy analysis was conducted on the CCHP system. •The CCHP performance serving a building cluster was evaluated by the dynamic data

  8. One-region model predicting water temperature and level in a spent fuel pit during loss of all AC power supplies

    A prediction system with a one-region model was developed to predict water temperature in a spent fuel pit (SFP) after the shutdown of its cooling systems based on three-dimensional (3D) thermal hydraulic behavior calculated by using the CFD software, FLUENT 6.3.26. The system was extended to calculate the water level in the SFP during loss of all AC power supplies. In the prediction system, decay heat calculated by using the burn-up calculation software, ORIGEN 2.2, and the previously proposed correlation for evaporation heat fluxes from the water surface to air were used. Predicted results were compared with 3D calculations and measured temperatures for the shutdown of cooling systems and with the water temperature and level measured in SFPs at the Fukushima Daiichi Nuclear Power Station for loss of all AC power supplies. As a result, the predicted temperatures were found to agree well with the 3D calculations and it was confirmed that ORIGEN 2.2 well predicted decay heat for fuel assemblies with large decay heat which had been taken relatively recently from the shutdown reactor core. However, it was shown that decay heat predicted by ORIGEN 2.2 was overestimated for longtime cooled fuel assemblies with small decay heat and the previously proposed evaporation heat flux correlation overestimated the water temperature in the SFP, too. (author)

  9. State of Charge-Based Active Power Sharing Method in a Standalone Microgrid with High Penetration Level of Renewable Energy Sources

    Yun-Su Kim

    2016-06-01

    Full Text Available Standalone microgrids, which are mainly constructed on island areas have low system inertia, may result large frequency deviations even for small load change. Moreover, increasing penetration level of renewable energy sources (RESs into standalone microgrids makes the frequency stability problem even worse. To overcome this problem, this paper proposes an active power sharing method with zero frequency deviations. To this end, a battery energy storage system (BESS is operated as constant frequency (CF control mode, whereas the other distributed generations (DGs are operated as an active and reactive power (PQ control mode. As a result, a state of charge (SOC of the BESS is changed as the system load varies. Based on the SOC deviation, DGs share the load change. The SOC data is assumed to be sent via communication system, hence the communication time delay is considered. To enhance reliability, controllers of DGs are designed to take account of the failure of communication system. The simulation results show that active power can be shared among DGs according to desired ratio without frequency deviations even for large variation of output power of RESs.

  10. Activation analysis of the PULSAR-II fusion power reactor

    The PULSAR-II pulsed tokamak power plant design utilizes a blanket made of the vanadium alloy, V-5Cr-5Ti, and cooled with liquid lithium. The shield is made of a mixture of the low activation austenitic steel (Tenelon) and vanadium. The blanket is assumed to be replaced every 5.6 full power years (FPY) and the shield is assumed to stay in place for 30 FPY. The activity induced in the blanket at the end of its lifetime is higher than the activity induced in the shield after 30 FPY. At shutdown, the blanket and shield activities are 2678 MCi and 1747 MCi, respectively. One year after shutdown the shield activity drops to 18 MCi compared to 84 MCi for the blanket. The total decay heat generated in the blanket at the end of its lifetime is 34.7 MW and drops to 17.6 MW within an hour. At shutdown, 25.3 MW of decay heat are generated in the shield, dropping to only 0.1 MW within the first year. One week after shutdown, the values of the integrated decay heat are 1770 GJ for the blanket and 469 GJ for the shield. The radwaste classification of the reactor structure is evaluated according to both the NRC 10CFR61 and Fetter waste disposal concentration limits. After 5.6 years of irradiation, the blanket will only qualify for Class C low level waste. After 30 years of operation, the shield will also qualify for disposal as Class C waste. Only remote maintenance will be allowed inside the containment building

  11. Reactive power control with CHP plants - A demonstration

    Nyeng, Preben; Østergaard, Jacob; Andersen, Claus A.;

    2010-01-01

    power rating of 7.3 MW on two synchronous generators. A closed-loop control is implemented, that remote controls the CHP plant to achieve a certain reactive power flow in a near-by substation. The solution communicates with the grid operator’s existing SCADA system to obtain measurements from the......In this project the potential for ancillary services provision by distributed energy resources is investigated. Specifically, the provision of reactive power control by combined heat and power plants is examined, and the application of the new standard for DER communication systems, IEC 61850...... lines to underground cables has changed the reactive power balance, and third, the TSO has introduced restrictions in the allowed exchange of reactive power between the transmission system and distribution grids (known as the Mvar-arrangement). The demonstration includes a CHP plant with an electric...

  12. A high-quality multi-level voltage source inverter suitable for high power/high voltage applications

    In this paper new magnitudes for D C side capacitors' voltages of a multi level voltage source inv enter are presented. Using these magnitudes of D C side capacitors voltage allow generation of Σ3k steps of A C output voltage by cascade connection of only N single-phase full bridge inverter. This subject has resulted in almost sinusoidal output voltage wave form. Approximated equal area pulse amplitude modulation technique is used to calculate the duration of each step of voltage, which has resulted in reduction of complexity of control circuit. A simple closed-loop controller is developed for controlling the voltage of D C side capacitors. Harmonic analysis and capacitor calculations are presented, too. Simulation results have been used to verify the overall operation of the proposed multi level voltage source inverter in feeding a R-L load with a stepped sinusoidal wave form

  13. Body fat distribution in the Finnish population: environmental determinants and predictive power for cardiovascular risk factor levels.

    Marti, B; Tuomilehto, J; Salomaa, V.; Kartovaara, L.; Korhonen, H.J.; Pietinen, P.

    1991-01-01

    STUDY OBJECTIVE--The aim was to examine (1) whether health habits are associated with body fat distribution, as measured by the waist/hip girth ratio, and (2) to what extent environmental factors, including anthropometric characteristics, explain the variability in levels of cardiovascular risk factors. DESIGN--The study was a population based cross sectional survey, conducted in the spring of 1987 as a part of an international research project on cardiovascular epidemiology. SETTING--The sur...

  14. Basic neutronphysical and thermal-hydraulic characteristics of five years fuel cycle at increased power level 1444 MWth

    In this paper the Dukovany NPP modernisation, 5-years fuel cycle characteristics and some experimental results are presented. The following conclusion have been made: 1) Five years fuel cycle with Gd-fuel is implementing successfully from the point of both views - calculation and operation. 2) Basic parameters of the core will be stabilised at new equilibrium level. 3) Positive influence of Gd-fuel utilisation to Tritium outlets was observed

  15. Low-level laser (light) therapy (LLLT) on muscle tissue: performance, fatigue and repair benefited by the power of light

    Ferraresi, Cleber; Hamblin, Michael R.; Parizotto, Nivaldo A.

    2012-01-01

    The use of low level laser (light) therapy (LLLT) has recently expanded to cover areas of medicine that were not previously thought of as the usual applications such as wound healing and inflammatory orthopedic conditions. One of these novel application areas is LLLT for muscle fatigue and muscle injury. Since it is becoming agreed that mitochondria are the principal photoacceptors present inside cells, and it is known that muscle cells are exceptionally rich in mitochondria, this suggests th...

  16. Self Esteem in Making Decision and The Interpretational Power of Decisionmaking Styles of Teacher Candidates Emotional Intelligence Levels

    Yılmaz, Ercan; ALTINOK, Vicdan

    2010-01-01

    The aim of this study was to seek out to what extend the emotional intelligence levels of university students who are to be teachers explained their self-esteem in decision making and decision making styles. The research group of this study composed of totally 415 senior students of education faculties of Selcuk University who were chosen according to random clustering samples. The findings of the study proved that there is a significant positive correlation between all sub-dimensions of emot...

  17. Power electronic topology and switching-concept for identification of the grid impedance at medium-voltage-level; Leistungselektronisches Schaltungskonzept zur Identifikation der Netzimpedanz auf der Mittelspannungsebene

    Do, Thanh Trung; Jordan, Michael; Langkowski, Hauke; Schulz, Detlef [Helmut-Schmidt-Univ., Hamburg (Germany). Professur fuer Elektrische Energiesysteme; Leutwyler, Reto [ABB Switzerland Ltd., Lenzburg (Switzerland). Semiconductors

    2011-07-01

    The grid impedance at a point of common coupling (PCC) is an important parameter for grid integration of Renewable Energies, because it determines the maximum input power capacity of the corresponding PCC. The grid impedance is time and frequency dependent, which makes an analytical or simulative identification challenging. Therefore in practise the data obtained from these calculations are often incorrect and do not reflect the real grid structure. In order to determine the grid impedance more accurately the Helmut-Schmidt-University is developing a novel measurement device to identify the time and frequency dependent grid impedance on the medium-voltage-level up to 20 kVrms. For the application in medium-voltage-grids a special switching concept with high voltage thyristors and innovative presspack-IGBTs has been developed in cooperation with ABB Switzerland Ltd./Semiconductors. This contribution presents the basic grid impedance measurement method and its realization with power electronic components. (orig.)

  18. Symmetric far field, short-wavelength (λ = 4.53 μm) MOPA quantum cascade lasers with Watt-level optical output power

    Full text: We present the design and first realization of short-wavelength (λ = 4.53 μm), single mode emitting quantum cascade lasers in a master oscillator power amplifier configuration. Watt-level peak optical output power is demonstrated for typical non-tapered 4 μm wide and 5.25 mm long (DFB: 1.25 mm, FP: 4 mm) devices. Far field measurements prove a symmetric, single-transverse-mode emission in TM00-mode with typical divergences of 25° in and 27° perpendicular to the growth direction. We demonstrate single mode tuning over a range of 7.9 cm-1 for temperatures between 263 K and 313 K and also single mode emission for different driving currents and varied pulse-lengths between 25 ns and 100 ns. The side mode suppression ratio is measured to be higher than 20 dB. (author)

  19. KAPS level-1 PSA- analysis of 6.6 kV class-IV power supply failure as initiating event

    Full text: For Kakrapar atomic power station (KAPS) level-l probabilistic safety analysis (PSA) studies failure of 6.6 kV CL-IV power supply system resulting from failure of both the routes of class-IV buses viz., route via buses A, B, C and route via buses F, G, H is considered as one of the initiating events for analysis. This can happen due to grid problems or due to combinations of component failures from both the routes. This event is one of the most important transient events in station transient analysis as it could lead to scenarios like station blackout depending upon the availability of emergency power supply system i.e.the diesel generator system. Upon failure of class-IV power, reactor trips on no PCP on either side followed by high PHT pressure trip. Following this event if class III is available, no safety system gets affected and the mode of decay heat removal and long-term reactivity control are same as normally followed. If class-III fails, reactor has to be crash cooled and fire water should be injected to SGs for decay heat removal. Class-IV failure followed by class-III failure leads to a station blackout scenario in which a number of front line systems become available. Event tree was developed showing the mitigating functions/ systems required sequentially for safe termination of the initiating event (IE). To estimate the accident sequence frequencies the success and failure probabilities of these mitigating functions/ systems were calculated by fault tree methods. The IE frequency estimates have been derived from experience at KAPS station. For component failure probabilities a judicious mix of generic and plant specific data was used. The details and results of the assessment are presented in the paper

  20. THE EFFECT OF CAFFEINE CONSUMPTION ON THE NON-AEROBIC POWER, THE FATIGUE INDEX AND THE BLOOD LACTATE LEVELS IN THE MALE ATHLETE STUDENTS

    Ranjbar Rouhola

    2010-06-01

    Full Text Available The main purpose of this research is to study the effect of caffeine consumption on the non-aerobic power, the fatigue index and the blood lactate levels in the male athlete students. Therefore, 16 individuals with the average weight (68/1 +_ 9/1kg, height (1/73+_7cm, and age (24+_2 years were selected based on the simple-randomized method from among volunteer participants, and they were divided as match pairs, based on pre-examined fatigue index, into the two groups of caffeine (n=8 and placebo (n=8. Subjects were asked to refrain from having any intensive physical activity 24 hours before the test starts and avoid eating or drinking any caffeine foods or drinks 48 hours before the test. The primary RAST test (pre-test was performed at least 4 hours after having a meal, and then the individuals blood lactate levels was measured after 6 minutes of the test. The secondary RAST test was done after a week exactly like the first session. The subjects continued caffeine consumption as usual and interrupt it 48 hours prior to the next test. In post-test, the subjects took 6mg caffeine or placebo in the form of gelatin capsules per one kilogram of their weight one hour prior to the test. The analysis of the result, with applying the statistical t-test method (p≤0.05 to the dependent and independent groups, showed that consumption of caffeine has a significant positive effect on average power; minimum power and fatigue index, while it does not have any significant effect on maximum power and the amount of blood lactate. It seems that caffeine consumption is effective in the recovery of fast short-term shuttle activities.

  1. Arc Power Limit and Distribution on the Large Negative Ion Source Based on JT-60 NNBI

    LEIGuangjiu; N.Umeda; M.Kawai; T.Yamamoto; M.Kuriyama; T.Ohga; N.Ebisawa; T.Yamazaki; M.Kusaka; K.Kikuchi; S.Hikida; K.Usui; M.Kazawa; S.Numazawa; K.Mogaki; A.Honda; F.Satoh; S.Norio; K.Ooshima

    2001-01-01

    The target of the large negative ion source based on neutral beam injection (N-NBI) is to produce neutral beam current of 22 A and beam power of 10 MW at 500 keV with duration time of 10 s. Since it was successfully operated in 1996, the 5.3 MW neutral beam power at 380 keV with duration time of 3 s has been achieved. In recent years improving and enhancing the beam power are going on. Several reasons such as plasma non-uniformity, higher beam density at the upper region in the beam profile,

  2. Level 1 and 2 probabilistic safety assessment technology study and its application in the design of CHASHMA nuclear power plant unit2

    The software used for Level 1,2 and 3 probabilistic safety assessment (PSA) has been developed by technique introduction as well as independent research. It has been studied and applied to integrating the design of CHASHMA Nuclear Power Plant unit 2 (C-2) with the Level 1 and 2 PSA technology, which include the analysis of initiating events, event trees, fault trees, dependency analysis, human reliability analysis, database analysis, event sequence quantification, plant damage state analysis, accident progression and containment response analysis, source term analysis, large early release frequency (LERF) analysis, uncertainty analysis, importance/sensitivity analysis, applications during design phase, and so on. The model of Level 1 and 2 PSA has been established for C-2. In the meantime, several significant design improvement has been implemented in the process of C-2 design based on the PSA insights, such as that of isolation valves on the mini-flow line of the safety injection pump and spray pump, reciprocating charging pump in chemical and volume control system, essential service water system, etc. Thus, the figures of merit for C-2 for the internal events at power operating condition have been achieved with 7.25E-6/ry for core damage frequency (CDF), 3.24E-07/ry for LERF. The C-2 PSA has not only justified the balance of its design, but also provided the probability assessment information for evaluating the optimization of C-2 design and operation strategies, efficiently reducing the risk of severe accidents. (authors)

  3. Pre operational levels of 137Cs and 90Sr in seawater and sea foods in Gulf of Mannar near Kudankulam Nuclear Power Plant

    The first unit of Kudankulam Nuclear Power Project (KKNPP) attained first criticality on July 13, 2013 and synchronized to the grid on October 22, 2013. The first unit achieved the full rated power of 1000 MWe on June 7, 2014. The second unit of KKNPP is under advanced stage of commissioning and hot run of the plant is expected shortly. Commercial operational of the first unit is expected soon. It is imperative to establish the pre operational levels of Fall out nuclides like 137Cs and 90Sr in and around Kudankulam site, especially sea waters and sea food samples as these nuclides are produced in the reactor as fission products. Nevertheless, they are retained in the fuel matrix itself as the reactors host a multiple layered barrier to prevent the escape of these radionuclides into the environment by adopting the philosophy of defense in depth. Benchmarking the levels of these nuclides in the aquatic domain will help in future comparison of the levels of these nuclides after the plants start operation in addition to generating the regional database in south eastern tip of the sea

  4. Radioactive contamination levels in China and health evaluation following radioactive release from Soviet Chernobyl Nuclear Power Plant accident

    For the purpose of evaluating radiological effects in China and protecting population from possible consequences of Soviet Chernobyl nuclear power plant accident, the national network of environmental radioactive monitoring stations in China started emergency monitoring since May 1st, 1986. From May 1st to the end of July, 131I, 137Cs and other man-made radionuclides in some environmental media were found in large amounts. 131I was detected obviously in daily deposition, surface water, growing leafy vegetables, fresh milk and sheep thyroid samples. It is proved that radioactive fallout from Soviet Chernobyl accident has spreaded in atmosphere over the territory of China; so, the environment has been contaminated. Thyroid dose for individuals of general public in China was estimated. The effective dose equivalents for adults are lower than 2 μSv, for infants lower than 30 μSv; they are low as compared with 'Basic Health Standards for Radiological Protection' in China. The emergency sanitary protective measures were considered unnecessary

  5. Investigation on the use digital controls instead of PID analog controls in the level control of steam generators of nuclear power PWR

    The aim of this study is to identify current alternatives for the implementation of digital controllers in the level control of steam generators of nuclear power PWR (Pressurized Water Reaetor). It is intended to identify the types of digital controls that are available from the theoretical and conceptual viewpoints for this purpose. We investigate the advantages and disadvantages of each controller model. From this assessment are pointed the most suitable models in hierarchical scale. This evaluation also serves to suggest possible types of control installation as a whole, where the level control of the steam generators becomes just one of many controls that are part of the plant. In this case, the use of digital controls allows the non-linear and multivariable treatment which is characteristic of complex systems, such as the nuclear power generation. The treatment of nonlinearities and multivariable aspects allows a more detailed study of the stability of these plants when they are subject to transients or several accidents, such as the case of losing external power of transients. In the specific case of steam generators, the instabilities result from the emergence of the shrink and swell phenomenas, depending on the load variations of thermonuclear plant. The application of several types and digital controllers, considering these inherent characteristics of the level control of steam generators, allows to infer which types of controllers are more appropriate to treat instabilities of this type and to make conjectures in its use for the cases of more complex instabilities, considering the integration of all nucleus-plant controls.

  6. Natural radioactive level in coal and ash and building material products from coal-fired power plants in Beijing

    The authors report the methods and results of survey on content of 226Ra, 232Th and 40K in samples of coal, ash from 5 coal-fired power plants in Beijing and ash bricks, air-added concrete from Beijing air-added concrete plant from February to December, 1993. 55 coal Samples, 26 ash Samples, 8 ash brick samples and 8 air-added concrete samples were collected. These samples were analysed by type FH-1936 low background γ-spectrometer. The average value of 226Ra, 232Th and 40K of coal is 28.9, 35.9 and 80.4 Bq/kg, respectively; 101, 110 and 347 Bq/kg, for ash; 47.6, 72.9 and 288 Bq/kg, for ash brick and 47.8, 70.1 and 216 Bq/kg for air-added concrete, respectively. In addition, γ radiation dose rate inside buildings of workers, dwelling houses of the Beijing air-added concrete plant made of ash building materials were investigated and analysed. The range and the average value of 8 measurement values is (67.4-84.7) nGy/h and 78.2 nGy/h, respectively. It approaches to the average value inside bungalow of bricks and a building of two or more storeys made of bricks and concrete in Beijing and within normal range. The results show that it might not cause obviously increase of γ radiation dose rate inside building when the ash were rationally used as the raw materials of building

  7. Effects of high intensity interval training and high volume endurance training on maximal aerobic capacity, speed and power in club level gaelic football players

    Cregg, Cathal J

    2013-01-01

    Purpose: To compare the effects of high intensity interval training (HIIT) and high volume endurance training (HVET) on indices of endurance, speed and power in male Gaelic football players. Methods: Club level Gaelic football players (n=25) ranging from 18 to 35 years of age were randomly assigned to a HIIT (mean ± SD; 27.2 ± 3.6 yr) or a HVET ( mean ± SD 24.7 ± 4.0 yr) group. Participants trained 3 d.wk-1 for 6 weeks. Maximal aerobic capacity, vertical jump (VJ), countermovement jump (C...

  8. Implementation of a Sage-Based Stirling Model Into a System-Level Numerical Model of the Fission Power System Technology Demonstration Unit

    Briggs, Maxwell H.

    2011-01-01

    The Fission Power System (FPS) project is developing a Technology Demonstration Unit (TDU) to verify the performance and functionality of a subscale version of the FPS reference concept in a relevant environment, and to verify component and system models. As hardware is developed for the TDU, component and system models must be refined to include the details of specific component designs. This paper describes the development of a Sage-based pseudo-steady-state Stirling convertor model and its implementation into a system-level model of the TDU.

  9. [Hygienic problems in the location of modern wind electric power stations in their design].

    Kireeva, I S; Makhniuk, V M; Akimenko, V Ia; Dumanskiĭ, Iu D; Semashko, P V

    2013-01-01

    Hygienic aspects of the placement of wind power plants (WPP) in connection with the intensive development of wind power and the lack of systematic information on their effects of the environment and living conditions of the population are becoming more actual. In the article there are considered results of the sanitary-epidemiological expertise of the construction project of three modern large wind farm (the South - Ukrainian, Tiligulskaya and Pokrovskaya) with a total capacity offrom 180 to 500 MW of wind farms with 2.3 MW power generators of wind turbines. It is shown that in the process of wind farm construction a contamination of the environment (air soil, ground water) may take place due to the working of construction equipment and vehicle, excavation, welding and other operations, in the exploitation of wind farm there can be created elevated levels of acoustic and electromagnetic pollution in the neighborhood and emergencies with the destruction of WPP in adverse weather conditions. Based on the calculations presented in the projects, and the analysis of data on the impact offoreign windfarm on the environment it was found that the limiting factor of the influence is the wind farm noise pollution in the audio frequency range that extends beyond the territory of wind fields, electromagnetic radiation is recorded within the hygienic standards and below only in the immediate vicinity of its sources (electrical equipment and power lines). For considered modern wind farms there was grounded sanitary protective zone with dimensions of 700 mfrom the outermost wind turbines by the noise and it was recommended compliance distance of200 mfrom the wind turbine to limit any activity and people staying in times of possible emergency situations in adverse weather conditions. PMID:24624820

  10. An Ergonomic Evaluation of the Illumination Level and the Management Plan to Improve the Working Environment of Nuclear Power Plants

    Shin, Kwang Hyeon; Lee, Yong Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    Illumination in the working environment is one of the crucial factors that affect worker's psychological status as well as the physiological condition according to each task. Sometimes it affects the results of worker's cognitive, perceptual work performance. In particular, illumination may become a triggering factor to human errors in visual tasks due to visual fatigue through direct influence of vision in NPPs. Illumination includes several visual conditions such as uniformity factor, light distribution, glare, SPD (Surge Protector Device), flicker, illumination system, daylight and window control, in addition to the simple physical aspects of illumination and luminance. These conditions may affect operators' visibility and disillusion level, cause stress, attention, emotion, etc. and they finally affect workers' performance and errors as a result. From the many illumination conditions mentioned above, current work environment evaluation items on illumination are mainly based only on the intensity of illumination, and there is yet no systematic way with evaluation criteria for other factors such as luminance, flickering, etc. In addition, research and development on illumination emphasizes mainly the physical characteristics of illumination, and it is insufficient for the influence studies on human error or work performance that are caused by these factors

  11. INDEPENDENT VERIFICATION SURVEY OF THE SPRU LOWER LEVEL HILLSIDE AREA AT THE KNOLLS ATOMIC POWER LABORATORY NISKAYUNA, NEW YORK

    Harpenau, Evan M.; Weaver, Phyllis C.

    2012-06-06

    During August 10, 2011 through August 19, 2011, and October 23, 2011 through November 4, 2011, ORAU/ORISE conducted verification survey activities at the Separations Process Research Unit (SPRU) site that included in-process inspections, surface scans, and soil sampling of the Lower Level Hillside Area. According to the Type-B Investigation Report, Sr-90 was the primary contributor to the majority of the activity (60 times greater than the Cs-137 activity). The evaluation of the scan data and sample results obtained during verification activities determined that the primary radionuclide of concern, Sr-90, was well below the agreed upon soil cleanup objective (SCO) of 30 pCi/g for the site. However, the concentration of Cs-137 in the four judgmental samples collected in final status survey (FSS) Units A and B was greater than the SCO. Both ORAU and aRc surveys identified higher Cs-137 concentrations in FSS Units A and B; the greatest concentrations were indentified in FSS Unit A.

  12. An Ergonomic Evaluation of the Illumination Level and the Management Plan to Improve the Working Environment of Nuclear Power Plants

    Illumination in the working environment is one of the crucial factors that affect worker's psychological status as well as the physiological condition according to each task. Sometimes it affects the results of worker's cognitive, perceptual work performance. In particular, illumination may become a triggering factor to human errors in visual tasks due to visual fatigue through direct influence of vision in NPPs. Illumination includes several visual conditions such as uniformity factor, light distribution, glare, SPD (Surge Protector Device), flicker, illumination system, daylight and window control, in addition to the simple physical aspects of illumination and luminance. These conditions may affect operators' visibility and disillusion level, cause stress, attention, emotion, etc. and they finally affect workers' performance and errors as a result. From the many illumination conditions mentioned above, current work environment evaluation items on illumination are mainly based only on the intensity of illumination, and there is yet no systematic way with evaluation criteria for other factors such as luminance, flickering, etc. In addition, research and development on illumination emphasizes mainly the physical characteristics of illumination, and it is insufficient for the influence studies on human error or work performance that are caused by these factors

  13. Independent Verification Survey Of The SPRU Lower Level Hillside Area At The Knolls Atomic Power Laboratory Niskayuna, New York

    During August 10, 2011 through August 19, 2011, and October 23, 2011 through November 4, 2011, ORAU/ORISE conducted verification survey activities at the Separations Process Research Unit (SPRU) site that included in-process inspections, surface scans, and soil sampling of the Lower Level Hillside Area. According to the Type-B Investigation Report, Sr-90 was the primary contributor to the majority of the activity (60 times greater than the Cs-137 activity). The evaluation of the scan data and sample results obtained during verification activities determined that the primary radionuclide of concern, Sr-90, was well below the agreed upon soil cleanup objective (SCO) of 30 pCi/g for the site. However, the concentration of Cs-137 in the four judgmental samples collected in final status survey (FSS) Units A and B was greater than the SCO. Both ORAU and aRc surveys identified higher Cs-137 concentrations in FSS Units A and B; the greatest concentrations were indentified in FSS Unit A

  14. Power and polarization dependences of ultra-narrow electromagnetically induced absorption (EIA) spectra of 85 Rb atoms in degenerate two-level system

    Qureshi, Muhammad Mohsin; Rehman, Hafeez Ur; Noh, Heung-Ryoul; Kim, Jin-Tae

    2016-05-01

    We have investigated ultra-narrow EIA spectral features with respect to variations of polarizations and powers of pump laser beam in a degenerate two-level system of the transition of 85 Rb D2 transition line. Polarizations of the probe laser beam in two separate experiments were fixed at right circular and horizontal linear polarizations, respectively while the polarizations of the pump lasers were varied from initial polarizations same as the probe laser beams to orthogonal to probe polarizations. One homemade laser combined with AOMs was used to the pump and probe laser beams instead of two different lasers to overcome broad linewidths of the homemade lasers. Theoretically, probe absorption coefficients have been calculated from optical Bloch equations of the degenerate two level system prepared by a pump laser beam. In the case of the circular polarization, EIA signal was obtained as expected theoretically although both pump and probe beams have same polarization. The EIA signal become smaller as power increases and polarizations of the pump and probe beams were same. When the polarization of the pump beam was linear polarization, maximum EIA signal was obtained theoretically and experimentally. Experimental EIA spectral shapes with respect to variations of the pump beam polarization shows similar trends as the theoretical results.

  15. Power MOSFET quality and robustness enhancement with a new Q{sub BD} characterization performed at probe-die-wafer level

    Pomes, Emilie, E-mail: epomes@laas.fr [CNRS, LAAS, 7 Av. du Colonel Roche, F-31077 Toulouse (France); Universite de Toulouse, UPS, INSA, INP, ISAE, LAAS, F-31077 Toulouse (France); Reynes, Jean-Michel [Freescale Semiconductor SAS, Av. du General Eisenhower, 31023 Toulouse (France); Tounsi, Patrick; Dorkel, Jean-Marie [CNRS, LAAS, 7 Av. du Colonel Roche, F-31077 Toulouse (France); Universite de Toulouse, UPS, INSA, INP, ISAE, LAAS, F-31077 Toulouse (France)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer We used a new way of electrical characterization with the charge-to-breakdown test. Black-Right-Pointing-Pointer Measurements are performed directly at probe-die-wafer level. Black-Right-Pointing-Pointer An accurate monitor has been developed to evaluate dice quality and reliability. Black-Right-Pointing-Pointer The extrinsic failures responsible for potential rejects can be identified. Black-Right-Pointing-Pointer Process and gate stress impact can be evaluated with the diversion of Q{sub BD} test. - Abstract: The quality of the gate oxide is a central parameter for power MOSFET devices dedicated to automotive applications. Reliability is systematically evaluated through electrical tests. The purpose of this study is to apply the Q{sub BD} test directly at probe-die-wafer level and to correlate its results with reliability test conclusions. In other words, this new kind of Q{sub BD} test is a monitor of power MOSFET robustness which helps identify extrinsic failures and the process steps responsible. In summary, it is an accurate and fast measurement method of identifying weakened parts and enhancing device quality.

  16. Disposal of high-level waste from nuclear power plants in Denmark. Salt dome investigations. v.2

    The present report deals with the geological investigations performed for determing the feasibility of a repository for high-level waste in a salt dome. It is volume 2 of five volumes that together constitute the final report of the Danish utilities' salt dome investigations. The purpose of the work was to procure a more detailed knowledge of the geology of salt domes in North Jutland on example of Mors. The Mors dome is oval with the two axes of approx. 12.5 km and 8 km respectively. Two deep wells have been drilled into the salt. These wells reach 3400-3500 m below surface. Until a depth of about 3200 m Erslev 2 passes through rock salt of Zechstein 1 which is the oldest evaporite series. However, it could also be interlayed with the slightly younger Zechstein 2. At about 3200 m a marker layer was met with Zechstein 2 salt below. Interpretation of cores and results of downhole electromagnetic and borehole gravimetric measurements show that there is a large area around Erslev 2 which consists of very pure sodium chloride with traces of anhydrite (calcium, sulphate) 1-3%. This area is used for the repository design and safety evaluation. The hydrological conditions existing in the strata above the salt dome (caprock) have been investigated with the help of four hydrogeological wells, placed two each, on two different sites. The cores themselves were taken at various depths in all four holes. With these laboratory methods it has been possible to measure data relevant to hydrology - such as porosity and permeability - as well as geochemistry. (BP)

  17. Photosynthetic pigments of phytoplankton in the surface water level of lake Drukshiai - cooler of Ignalina nuclear power plant (NPP)

    Investigations on photosynthetic pigments carried out in 1986-1993 indicated that the amount of chlorophyll a (Ca) in the surface water level of lake Drukshiai - cooler of the Ignalina NPP ranged from 0.03 to 21.61 mkg/l. The highest amount of Ca (1.19-21.61 mkg/l) was registered at the 6th station, which is influenced by municipal waste waters of Visaginas, and the lowest amount (0.05-6.22 mkg/l) was observed on the warm water outlet area (4th station). The percentage of Ca increases in phytoplankton biomass due to the high content of Chrysophyta Pyrrophyta, Chlorophyta and some Cyanophyta algae. The quantitative dynamics of carotenoids (Ck) is related with phytoplankton biomass, its specific structure and Ca amount. Phytoplankton of lake Drukshiai is in a good physiological condition with high photosynthetical activity. The day assimilation number (DAN) during the intensive vegetation of phytoplankton (July) ranged from 12 to 90 mkg C/mkg of Ca on the whole investigated water area of the lake. The pigment index (PI) in most cases ranged from 2 to 4, the Ck/Ca ratio being from 0.6 to 2. In the warm water outlet area a high amount of pheopigments - Ca destruction products (exceeding 50% of the amount) was determined. The PI and Ck/Ca ratio in most cases was higher than in the other tested stations, however the high DAN (in May 1991 - 76.2 mkg C/mkg Ca) indicated that, besides the dissociated nonviable phytoplankton cells, there were a lot of photosynthetically active forms of microalgae.(author). 6 figs., 2 tabs., 19 refs

  18. 县级供电企业培训质量控制探讨%Inquiry of Training Quality Control of County-level Power Supply Enterprise

    张威; 苏健祥; 张惠聪

    2012-01-01

    This paper introduces an advanced training management philosophy and proposes training quality control model, by analyzing the common three major errors in the training of quality management. It defines training quality control QOCT quantitative model Q =O×C×T,.and processes system analysis and argument, combining with the actual situation of internal training of the county-level power supply enterprise. To Foshan Sanshui Power Supply Bureau, for example, it describes the practical application of the model QOCT measures, and the results achieved after the execution. It is a bold attempt to innovative for Quality control QOCT training establishment and application of the model. It is a control guidance and reference for quality control training of county-level power supply enterprise.%本文通过分析培训质量管理上常见的三大误区,引入先进培训管理理念,提出培训质量控制模型,并结合县级供电企业内部培训实际情况,定义了培训质量控制的QOCT量化模型Q=O×C×T,并进行了系统分析与论证.本文以佛山三水供电局为例,介绍了QOCT模型的实践应用措施,及执行后取得的成效.QOCT培训质量控制模型的建立与运用,是一次大胆创新的尝试,对县级供电企业的培训质量控制有一定的指导和参考意义.

  19. Disposal of high-level waste from nuclear power plants in Denmark. Salt dome investigations. v.5

    The present report deals with safety evaluation as part of the investigations regarding a repository for high-level waste in a salt dome. It is volume 5 of five volumes that together constitute the final report on the Danish utilities' salt dome investigations. Two characteristics of the waste are of special importance for the safety evaluation: the encasing of the waste in steel casks with 15 cm thick walls affording protection against corrosion, protecting the surroundings against radiation, and protecting the glass cylinders from mechanical damage resulting from the pressure at the bottom of the disposal hole, and the modest generation of heat in the waste at the time of disposal resulting in a maximum temperature increase in the salt close to the waste of approx. 40 deg. C. These characteristics proved to considerably improve the safety margin with respect to unforeseen circumstances. The character of the salt dome and of the salt in the proposed disposal area offers in itself good protection against contact with the ground water outside the dome. The relatively large depth of 1200 and 2500 m of the salt surface also means that neither dome nor disposal facility will be appreciably influenced by glaciations or earthquakes. The chalk above the proposed disposal area is very tight and to retain radioactive matter effectively even in the precence of high concentrations of NaCL. The safety investigations included a number of natural processes and probable events such as the segregation of crystal water from overlooked salt minerals, faulty sealings of disposal holes, permeable fault zones in the chalk overlying the dome, the risk in connection with human penetration into the dome. These conditions will neither lead to the destruction of the waste casks or to the release of waste from the dome. Leaching of a cavern is the only situation which proved to result in a release of radioactive material to the biosphere, but the resulting doses was found to be small

  20. Greater-than-Class C low-level radioactive waste characterization. Appendix A-2: Timing of greater-than-Class C low-level radioactive waste from nuclear power plants

    Planning for the storage or disposal of greater-than-Class C low-level radioactive waste (GTCC LLW) requires characterization of that waste. Timing, or the date the waste will require storage or disposal, is an integral aspect of that planning. The majority of GTCC LLW is generated by nuclear power plants, and the length of time a reactor remains operational directly affects the amount of GTCC waste expected from that reactor. This report uses data from existing literature to develop high, base, and low case estimates for the number of plants expected to experience (a) early shutdown, (b) 40-year operation, or (c) life extension to 60-year operation. The discussion includes possible effects of advanced light water reactor technology on future GTCC LLW generation. However, the main focus of this study is timing for shutdown of current technology reactors that are under construction or operating

  1. Methodology for evaluating radiological consequences of the management of very low-level solide waste arising from decommissioning of nuclear power plants

    In this report a methodology is described, and illustrated by examples, for the evaluation of individual doses and collective dose commitments arising as a result of various management modes for very low-level solid wastes arising from the decommissioning of nuclear power plants. Estimates have been made of the masses of materials activated and contaminated to within three concentration limits, 0.37, 3.7 and 37 Bq g-1, at three times after reactor shutdown, 5 y, 25 y and 100 y. The disposal options considered are shallow land burial, at a municipal landfill site or at the reactor site, and disposal on the seabed in coastal waters or the deep ocean. It is assumed that there is no special treatment to reduce or eliminate the potential radiological hazard. Consideration has also been given to the radiological impact of recycling of contaminated steel. The radiological impacts of all the management options for the wastes considered were found to be small. It may therefore be acceptable to allow such very low-level wastes to be disposal of without special restrictions provided that the level and type of activity of the wastes can be verified. In addition the health detriment cost associated with all the management options is small, so it is likely that other factors such as transport and engineering costs will be more important in final decisions about the management of these wastes

  2. Thai Nuclear Power Program

    The Electricity Generating Authority of Thailand (EGAT), the main power producer in Thailand, was first interested in nuclear power as an electricity option in 1967 when the electricity demand increased considerably for the first time as a result of the economic and industrial growth. Its viability had been assessed several times during the early seventies in relation to the changing factors. Finally in the late 1970s, the proceeding with nuclear option was suspended for a variety of reasons, for instance, public opposition, economic repercussion and the uncovering of the indigenous petroleum resources. Nonetheless, EGAT continued to maintain a core of nuclear expertise. During 1980s, faced with dwindling indigenous fossil fuel resources and restrictions on the use of further hydro as an energy source, EGAT had essentially reconsidered introducing nuclear power plants to provide a significant fraction to the long term future electricity demand. The studies on feasibility, siting and environmental impacts were conducted. However, the project was never implemented due to economics crisis in 1999 and strong opposition by environmentalists and activists groups. The 1986 Chernobyl disaster was an important cause. After a long dormant period, the nuclear power is now reviewed as one part of the solution for future energy supply in the country. Thailand currently relies on natural gas for 70 percent of its electricity, with the rest coming from oil, coal and hydro-power. One-third of the natural gas consumed in Thailand is imported, mainly from neighbouring Myanmar. According to Power Development Plan (PDP) 2007 rev.2, the total installed electricity capacity will increase from 28,530.3 MW in 2007 to 44,281 MW by the end of plan in 2021. Significantly increasing energy demand, concerns over climate change and dependence on overseas supplies of fossil fuels, all turn out in a favor of nuclear power. Under the current PDP (as revised in 2009), two 1,000- megawatt nuclear

  3. Development of a 325 MHz high power klystron

    A new high power CW klystron has been developed for Chinese Accelerator Driven System. The klystron is horizontally-oriented and outputs 600-kW CW power at 325 MHz, designed on the basis of the 324-MHz, 3-MW, pulsed klystron E3740A. It mainly consists of a triode electron gun, a six-cavity interaction circuit, a coaxial window, an output waveguide equipped with a T-bar converter and a force-water-cooled collector. The RF interaction circuit is optimized to obtain efficiency more than 60% for the nominal output power. The collector is capable of handling up to 1.1 MW to work with non-RF condition. Stable operation with an output power of 614 kW and an efficiency of 62.2% was achieved in the test performed in May, 2013. (author)

  4. Effect of liquid level and laser power on the formation of spherical alumina nanoparticles by nanosecond laser ablation of alumina target

    Al-Mamun, Sharif Abdullah [Research Center for Micro-Nano Technology, Hosei University, 3-11-15 Midori-cho, Koganei, Tokyo 184-0003 (Japan); Nakajima, Reiko [Department of Materials Chemistry, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584 (Japan); Ishigaki, Takamasa, E-mail: ishigaki@hosei.ac.jp [Research Center for Micro-Nano Technology, Hosei University, 3-11-15 Midori-cho, Koganei, Tokyo 184-0003 (Japan); Department of Materials Chemistry, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584 (Japan); Department of Chemical Science and Technology, 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584 (Japan); Nano Ceramics Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2012-11-15

    Alumina nanoparticles (NPs) were synthesized by laser ablation of a bulk {alpha}-alumina (corundum) target immersed in distilled water using nanosecond laser pulses of 1064-nm wavelength. We investigated the effect of laser power and water column above the target. Synthesized particles were analyzed regarding particle shape and size distributions with scanning electron and transmission electron microscopy. Ablated NPs were spherical in shape and the average particle size ranged from 12 to 18 nm at varied laser power and water levels, although a very small number of melted droplets of submicron spheroids and irregular-shaped cracked particles were observed. X-ray diffraction analysis was conducted, which shows mainly the peaks of {alpha}-Al{sub 2}O{sub 3} and minor peaks of {gamma}-Al{sub 2}O{sub 3}. Phase identification of NPs, using high-resolution transmission electron micrograph lattice images and fast Fourier transform exhibits both metastable {gamma}-Al{sub 2}O{sub 3} and stable {alpha}-Al{sub 2}O{sub 3} phases.

  5. The future of distributed power in Alberta

    Maxim Power Corporation is a provider of distributed energy and environmental solutions with a total of 55 MW of installed generating capacity in Canada, Europe and Asia, with 35 MW in Alberta. The 8 MW Taber facility in southern Alberta was described. Maxim operates 25 other small scale power generation stations (1 MW units) across 4 sites in southern Alberta. All the sites are interconnected at 25 kV and are eligible for distribution credits. The 3 MW EVI facility which utilizes solution gas was also described in the PowerPoint presentation. Maxim operates an additional 3 projects totaling 10 MW. The paper made reference to issues regarding market attributes for distributed power, policy framework and the transition to a competitive power market in Alberta. The chronology of events in Alberta's power market from August 2000 to June 2001 was outlined. The impacts of deregulation on distributed power include: (1) artificially low price environment from market intervention, (2) high efficiency cogeneration opportunities have been eliminated, (3) business failures and reduced investment, and (4) private investment not afforded the same alternative cost recovery mechanisms as the Alberta balancing pool. The presentation concluded with a report card for Alberta's deregulation, giving a grade F for both present and future opportunities for distributed power in Alberta. 2 figs

  6. Geothermal power, policy, and design: Using levelized cost of energy and sensitivity analysis to target improved policy incentives for the U.S. geothermal market

    Richard, Christopher L.

    At the core of the geothermal industry is a need to identify how policy incentives can better be applied for optimal return. Literature from Bloomquist (1999), Doris et al. (2009), and McIlveen (2011) suggest that a more tailored approach to crafting geothermal policy is warranted. In this research the guiding theory is based on those suggestions and is structured to represent a policy analysis approach using analytical methods. The methods being used are focus on qualitative and quantitative results. To address the qualitative sections of this research an extensive review of contemporary literature is used to identify the frequency of use for specific barriers, and is followed upon with an industry survey to determine existing gaps. As a result there is support for certain barriers and justification for expanding those barriers found within the literature. This method of inquiry is an initial point for structuring modeling tools to further quantify the research results as part of the theoretical framework. Analytical modeling utilizes the levelized cost of energy as a foundation for comparative assessment of policy incentives. Model parameters use assumptions to draw conclusions from literature and survey results to reflect unique attributes held by geothermal power technologies. Further testing by policy option provides an opportunity to assess the sensitivity of each variable with respect to applied policy. Master limited partnerships, feed in tariffs, RD&D, and categorical exclusions all result as viable options for mitigating specific barriers associated to developing geothermal power. The results show reductions of levelized cost based upon the model's exclusive parameters. These results are also compared to contemporary policy options highlighting the need for tailored policy, as discussed by Bloomquist (1999), Doris et al. (2009), and McIlveen (2011). It is the intent of this research to provide the reader with a descriptive understanding of the role of

  7. Development of plant-level automatic voltage control system for power plant%火电厂厂级自动电压控制系统研制

    翟伟翔; 周宇华; 苏适; 刘友宽

    2011-01-01

    An integrated AVC(Automatic Voltage Control) substation is developed based on existing plant -level automatic generation control system for power plant. The gain of adaptive PID adjuster is properly modified by the dynamic identification of system impedance and the voltage and reactive power are online switched for realizing the error-free and quick adjustment. The bias adjustment algorithm is put forward based on traditional equivalent power factor distribution and reactive power capacity coefficient distribution and the calculation formulas are given. Technical issues of parameter collection, operating mode and protective blocking are described for practical application. Site operation proves that,the proposed AVC system operates stably and reliably with flexible operating manner, good adjustment property and perfect security mechanism.%为保证电网安全、优质、经济运行,将火电厂自动电压控制在现有厂级自动发电控制系统平台上扩展实施,构成了一体化专用子站.通过动态辨识系统阻抗,适当修正自适应PID调节器的增益,进行电压和无功的在线转换,实现无差、快速调节.在传统的等功率因数分配方法与无功容量系数分配方法基础上提出了偏置调整算法,给出了计算公式.针对实际应用,阐述了参数采集、运行模式、闭锁保护等方面的技术问题.通过电厂的实际运行,证明该系统能够稳定可靠地工作,并具有操作方式灵活、调节品质较好、故障与安全处理机制完善等特点.

  8. Power Converters and Power Quality

    Kahle, K

    2015-01-01

    This paper discusses the subject of power quality for power converters. The first part gives an overview of most of the common disturbances and power quality issues in electrical networks for particle accelerators, and explains their consequences for accelerator operation. The propagation of asymmetrical network disturbances into a network is analysed. Quantitative parameters for network disturbances in a typical network are presented, and immunity levels for users’ electrical equipment are proposed. The second part of this paper discusses the technologies and strategies used in particle accelerator networks for power quality improvement . Particular focus is given to networks supplying loads with cycling active and reactive power

  9. Influence of the power level of an ultra-sonic system on dental cavity preparation Influência do nível de potência de um sistema de ultra-som em preparos cavitários

    Érika Botelho Josgrilberg; Murilo de Sousa Guimarães; Cyneu Aguiar Pansani; Rita de Cássia Loiola Cordeiro

    2007-01-01

    The aim of this study was to evaluate the shape of dental cavities made with the CVDentus® system using different ultrasound power levels. One standard cavity was made on the buccal aspect of 15 bovine incisors with a CVDentus® cylindrical bur (82142). The sample was divided into three groups: G1 - ultrasound with power II; G2 - ultrasound with power III; and G3 - ultrasound with power IV. A standardizing device was used to obtain standardized preparations and ultrasound was applied during on...

  10. INSTALLATION OF A POST-ACCIDENT CONFINEMENT HIGH-LEVEL RADIATION MONITORING SYSTEM IN THE KOLA NUCLEAR POWER STATION (UNIT 2) IN RUSSIA

    This is the final report on the INSP project entitled, ''Post-Accident Confinement High-Level Radiation Monitoring System'' conducted by BNL under the authorization of Project Work Plan WBS 1.2.2.6 (Attachment 1). This project was initiated in February 1993 to assist the Russians in reducing risks associated with the continued operation of older Soviet-designed nuclear power plants, specifically the Kola VVER-440/230 Unit 2, through improved accident detection capability, specifically by the installation of a dual train high-level radiation detection system in the confinement of Unit 2 of the Kola NPP. The major technical objective of this project was to provide, install and make operational the necessary hardware inside the confinement of the Kola NPP Unit 2 to provide early and reliable warning of the release of radionuclides from the reactor into the confinement air space as an indication of the occurrence of a severe accident at the plant. In addition, it was intended to provide hands-on experience and training to the Russian plant workers in the installation, operation, calibration and maintenance of the equipment in order that they may use the equipment without continued US assistance as an effective measure to improve reactor safety at the plant

  11. Behaviour of rocks and mechanical model of leads on the powered supports in a fully mechanized sub-level caving face

    Shi, Y. [China Coal Research Institute (China). Beijing Research Institute of Coal Mining

    1997-06-01

    Based on the study of distribution of abutment pressure and movement of overlying rocks and main roof, the decisive effect of the weakened degree of the immediate roof (penetration of shear cracks) and width of the completely failed zone of the top coal in ground pressure manifestation period are studied. Based on which, a mechanical model for calculation of the loads on the powered supports in a sub-level caving face is established. Formulae and examples are given for calculation of loads on the supports by considering the width of the completely plastic zone in top coal in the conditions of different weakness of the immediate roof in case of a long rock beam weighting and semi-arch instability of narrow rock beam. The fracture degree of the immediate roof and the width of the failed zone in top coal are the main criteria for the control of face and in the optimal design of sub-level caving face. 2 refs., 7 figs., 2 tabs.

  12. INSTALLATION OF A POST-ACCIDENT CONFINEMENT HIGH-LEVEL RADIATION MONITORING SYSTEM IN THE KOLA NUCLEAR POWER STATION (UNIT 2) IN RUSSIA

    GREENE,G.A.; GUPPY,J.G.

    1998-09-01

    This is the final report on the INSP project entitled, ``Post-Accident Confinement High-Level Radiation Monitoring System'' conducted by BNL under the authorization of Project Work Plan WBS 1.2.2.6 (Attachment 1). This project was initiated in February 1993 to assist the Russians in reducing risks associated with the continued operation of older Soviet-designed nuclear power plants, specifically the Kola VVER-440/230 Unit 2, through improved accident detection capability, specifically by the installation of a dual train high-level radiation detection system in the confinement of Unit 2 of the Kola NPP. The major technical objective of this project was to provide, install and make operational the necessary hardware inside the confinement of the Kola NPP Unit 2 to provide early and reliable warning of the release of radionuclides from the reactor into the confinement air space as an indication of the occurrence of a severe accident at the plant. In addition, it was intended to provide hands-on experience and training to the Russian plant workers in the installation, operation, calibration and maintenance of the equipment in order that they may use the equipment without continued US assistance as an effective measure to improve reactor safety at the plant.

  13. Additional heating power supplies: Design concept and first operation

    Two additional heating methods are used in JET, e.g. the Neutral Injection (NI heating) and the Ion Cyclotron Resonance Heating (RF Heating). In the RF heating, 10 generators each deliver 3MW to their antenna; for the NI heating 16 ion sources each delivering 4.8MW ion beam are installed. In order to minimize the internal dissipation in the generator and hence to obtain the maximum output power of the RF generators under the varying load conditions given by the plasma, the high voltage on the anode of the tetrode is varied. This is one of the main features of the power supply. The requirements for the NI power supply are different to the ones for the RF power supply. The accelerating grid (G1) power supply has to be very stable and must be able to switch off in 10 microsec in case of a breakdown in the accelerating structure and re-apply within 50 ms. Both these functions, voltage regulation and switching on and off are performed by a high power tetrode (protection system). In addition to the accelerating grid power supply, other power supplies (Aux PS) are necessary. They are the arc power supply, the filament power supply, the suppression grid (G3) power supply, the gradient grid (G2) power supply and the bending magnet power supply

  14. {sup 14}C emission from Swedish nuclear power plants and its effect on the {sup 14}C levels in the environment

    Stenstroem, K.; Erlandsson, Bengt; Hellborg, R.; Kiisk, M.; Persson, Per [Lund Univ. (Sweden). Dept. of Nuclear Physics; Mattsson, Soeren; Thornberg, C. [Lund Univ., Malmoe (Sweden). Dept. of Radiation Physics; Skog, G. [Lund Univ. (Sweden). Dept. of Quaternary Geology

    2000-02-15

    The radionuclide {sup 14}C is produced in all types of nuclear reactors mainly by neutron induced reactions in oxygen ({sup 17}O), nitrogen ({sup 14}N) and carbon ({sup 13}C). Part of the {sup 14}C created is continuously released during normal operation as airborne effluents in various chemical forms (such as CO{sub 2}, CO and hydrocarbons) to the surroundings. Because of the biological importance of carbon and the long physical half-life of {sup 14}C, it is of interest to measure the releases and their incorporation into living material. The {sup 14}C activity concentrations in annual tree rings and air around two Swedish nuclear power plants (Barsebaeck and Forsmark) as well as the background {sup 14}C activity levels from two reference sites in southern Sweden during 1973-1996 are presented in this report. In order to verify the reliability of the method some investigations have been conducted at two foreign nuclear sites, Sellafield fuel reprocessing plant in England, and Pickering nuclear generating station in Canada, where the releases of {sup 14}C are known to be substantial. Furthermore, results from some measurements in the vicinity of Paldiski submarine training centre in Estonia are presented. The results of the {sup 14}C measurements of air, vegetation and annual tree rings around the two Swedish nuclear power plants show very low enhancements of {sup 14}C, if at all above the uncertainty of the measurements. Even if the accuracy of the measurements of the annual tree rings is rather good (1-2%) the contribution of {sup 14}C from the reactors to the environment is so small that it is difficult to separate it from the prevailing background levels of {sup 14}C . This is the case for all sampling procedures: in air and vegetation as well as in annual tree rings. Only on a few occasions an actual increase is observed. However, although the calculations suffer from rather large uncertainties, the calculated release rate from Barsebaeck is in fair agreement

  15. Design, development and operational experience of radio frequency (RF) power systems/technologies for LEHIPA and 400 keV RFQ

    The important technology development for ion accelerators of 'accelerator driven sub critical reactor system (ADS) is being done under the program of Department of Atomic Energy (DAE). In BARC (BARC) of DAE, technology development of 400 keV radio frequency quadrupole (RFQ) accelerator is done and a 20 MeV - low energy high intensity proton accelerator (LEHIPA) is under development. A 400 KeV deuteron RFQ accelerator is already developed at BARC and its 60 kW radio frequency (RF) power system required for beam acceleration has been designed, developed and tested both in CW mode and in pulse mode for full power of 60 leW. It has been successfully integrated with RFQ via 6-1/8'', 50 ohm RF transmission line, to accelerate proton beam up to 200 KeV energy and deuteron beam to 400 KeV energy. LEHIPA requires about 3 MW of RF power for its operation. So, three 1 MW, 352 MHz RF systems based on klystron will be developed for RFQ and two DTLs. The klystron based RF system for 3 MeV RFQ is under commissioning. Its various subsystems like energy less and insulated gate bipolar transistor (IGBT) based high voltage and low voltage bias supplies, a critical and fast protection and control system - handling various types of field signals, fast acting hard wired instrumentation circuits for critical signals, 100 kV crowbar with its circuits, pulsing circuits and RF circuits have been successfully designed, developed and integrated with klystron. Latest technology development of solid state RF amplifiers at 325 MHz and 350 MHz for normal and super conducting accelerators has attained a certain power level. This paper will discuss all these high power RF systems in detail. (author)

  16. Removal of high-level radioactive substances contained with water from the Fukushima No. 1 Nuclear Power Stations. Some technical problems in waste treatment

    The Japanese government and plant operator Tokyo Electric Power Co. announced to process the highly radioactive water amounting to about 250,000 cubic meters by the end of fiscal year 2011. Radiation-contaminated water will be moved to the waste facility to remove oil and radioactive cesium using zeolite. The process using Prussian Blue is expected for the effectiveness. Other radioactive substances will be removed through precipitation using special chemicals and radioactivity in the water will be reduced to 10-6 of its original level. The water will be then be returned to the reactors and used to cool them after going through a desalination process. The facility can process about 1,200 tons of contaminated water a day. TEPCO will store radioactive materials and other waste from the cleansing process at the Fukushima plant. They need to decide how the waste will finally be disposed of and to figure out what to do with the highly radioactive waste produced in the above process. Kurion Inc., Areva SA, and some domestic firms provide equipment and technology, but all the Japanese facilities and institutions should join to settle the problems. (S. Ohno)

  17. High temperature heat source generation with quasi-continuous wave semiconductor lasers at power levels of 6 W for medical use.

    Fujimoto, Takahiro; Imai, Yusuke; Tei, Kazuyoku; Ito, Shinobu; Kanazawa, Hideko; Yamaguchi, Shigeru

    2014-01-01

    We investigate a technology to create a high temperature heat source on the tip surface of the glass fiber proposed for medical surgery applications. Using 4 to 6 W power level semiconductor lasers at a wavelength of 980 nm, a laser coupled fiber tip was preprocessed to contain a certain amount of titanium oxide powder with a depth of 100 μm from the tip surface so that the irradiated low laser energy could be perfectly absorbed to be transferred to thermal energy. Thus, the laser treatment can be performed without suffering from any optical characteristic of the material. A semiconductor laser was operated quasi-continuous wave mode pulse time duration of 180 ms and >95% of the laser energy was converted to thermal energy in the fiber tip. Based on two-color thermometry, by using a gated optical multichannel analyzer with a 0.25 m spectrometer in visible wavelength region, the temperature of the fiber tip was analyzed. The temperature of the heat source was measured to be in excess 3100 K. PMID:24853040

  18. Release of radionuclides and chelating agents from cement-solidified decontamination low-level radioactive waste collected from the Peach Bottom Atomic Power Station Unit 3

    As part of a study being performed for the Nuclear Regulatory Commission (NRC), small-scale waste-form specimens were collected during a low oxidation-state transition-metal ion (LOMI)-nitric permanganate (NP)-LOMI solidification performed in October 1989 at the Peach Bottom Atomic Power Station Unit 3. The purpose of this program was to evaluate the performance of cement-solidified decontamination waste to meet the low-level waste stability requirements defined in the NRC's ''Technical Position on Waste Form,'' Revision 1. The samples were acquired and tested because little data have been obtained on the physical stability of actual cement-solidified decontamination ion-exchange resin waste forms and on the leachability of radionuclides and chelating agents from those waste forms. The Peach Bottom waste-form specimens were subjected to compressive strength, immersion, and leach testing in accordance with the NRC's ''Technical Position on Waste Form,'' Revision 1. Results of this study indicate that the specimens withstood the compression tests (>500 psi) before and after immersion testing and leaching, and that the leachability indexes for all radionuclides, including 14C, 99 Tc, and 129I, are well above the leachability index requirement of 6.0, required by the NRC's ''Technical Position on Waste Form,'' Revision 1

  19. Co-Design Method and Wafer-Level Packaging Technique of Thin-Film Flexible Antenna and Silicon CMOS Rectifier Chips for Wireless-Powered Neural Interface Systems.

    Okabe, Kenji; Jeewan, Horagodage Prabhath; Yamagiwa, Shota; Kawano, Takeshi; Ishida, Makoto; Akita, Ippei

    2015-01-01

    In this paper, a co-design method and a wafer-level packaging technique of a flexible antenna and a CMOS rectifier chip for use in a small-sized implantable system on the brain surface are proposed. The proposed co-design method optimizes the system architecture, and can help avoid the use of external matching components, resulting in the realization of a small-size system. In addition, the technique employed to assemble a silicon large-scale integration (LSI) chip on the very thin parylene film (5 μm) enables the integration of the rectifier circuits and the flexible antenna (rectenna). In the demonstration of wireless power transmission (WPT), the fabricated flexible rectenna achieved a maximum efficiency of 0.497% with a distance of 3 cm between antennas. In addition, WPT with radio waves allows a misalignment of 185% against antenna size, implying that the misalignment has a less effect on the WPT characteristics compared with electromagnetic induction. PMID:26694407

  20. Co-Design Method and Wafer-Level Packaging Technique of Thin-Film Flexible Antenna and Silicon CMOS Rectifier Chips for Wireless-Powered Neural Interface Systems

    Kenji Okabe

    2015-12-01

    Full Text Available In this paper, a co-design method and a wafer-level packaging technique of a flexible antenna and a CMOS rectifier chip for use in a small-sized implantable system on the brain surface are proposed. The proposed co-design method optimizes the system architecture, and can help avoid the use of external matching components, resulting in the realization of a small-size system. In addition, the technique employed to assemble a silicon large-scale integration (LSI chip on the very thin parylene film (5 μm enables the integration of the rectifier circuits and the flexible antenna (rectenna. In the demonstration of wireless power transmission (WPT, the fabricated flexible rectenna achieved a maximum efficiency of 0.497% with a distance of 3 cm between antennas. In addition, WPT with radio waves allows a misalignment of 185% against antenna size, implying that the misalignment has a less effect on the WPT characteristics compared with electromagnetic induction.