WorldWideScience

Sample records for steam gt dynamics

  1. Characteristic analysis of rotor dynamics and experiments of active magnetic bearing for HTR-10GT

    International Nuclear Information System (INIS)

    Yang Guojun; Xu Yang; Shi Zhengang; Gu Huidong

    2005-01-01

    A 10 MW high-temperature gas-cooled reactor (HTR-10) was constructed by the Institute of Nuclear and New Energy Technology (INET) at Tsinghua University of China. The helium turbine and generator system of 10 MW high temperature gas-cooled reactor (HTR-10GT) is the second phase for the HTR-10 project. It is to set up a direct helium cycle to replace the current steam cycle. The active magnetic bearing (AMB) instead of ordinary mechanical bearing was chosen to support the rotor in the HTR-10GT. This rotor is vertically mounted to hold the turbine machine, compressors and the power generator together. The rotor's length is 7 m, its weight is about 1500 kg and the rotating speed is 15000 r/min. The structure of the rotor is so complicated that dynamic analysis of the rotor becomes difficult. One of the challenging problems is to exceed natural frequencies with enough stability and safety during reactor start up, power change and shutdown. The dynamic analysis of the rotor is the base for the design of control system. It is important for the rotor to exceed critical speeds. Some kinds of software and methods, such as MSC.Marc, Ansys, and the Transfer Matrix Method, are compared to fully analyze rotor dynamics characteristic in this paper. The modal analysis has been done for the HTR-10GT rotor. MSC.Marc was finally selected to analyze the vibration mode and the natural frequency of the rotor. The effects of AMB stiffness on the critical speeds of the rotor were studied. The design characteristics of the AMB control system for the HTR-10GT were studied and the related experiment to exceed natural frequencies was introduced. The experimental results demonstrate the system functions and validate the control scheme, which will be used in the HTR-10GT project. (authors)

  2. Thermo-economic comparative analysis of gas turbine GT10 integrated with air and steam bottoming cycle

    Science.gov (United States)

    Czaja, Daniel; Chmielnak, Tadeusz; Lepszy, Sebastian

    2014-12-01

    A thermodynamic and economic analysis of a GT10 gas turbine integrated with the air bottoming cycle is presented. The results are compared to commercially available combined cycle power plants based on the same gas turbine. The systems under analysis have a better chance of competing with steam bottoming cycle configurations in a small range of the power output capacity. The aim of the calculations is to determine the final cost of electricity generated by the gas turbine air bottoming cycle based on a 25 MW GT10 gas turbine with the exhaust gas mass flow rate of about 80 kg/s. The article shows the results of thermodynamic optimization of the selection of the technological structure of gas turbine air bottoming cycle and of a comparative economic analysis. Quantities are determined that have a decisive impact on the considered units profitability and competitiveness compared to the popular technology based on the steam bottoming cycle. The ultimate quantity that can be compared in the calculations is the cost of 1 MWh of electricity. It should be noted that the systems analyzed herein are power plants where electricity is the only generated product. The performed calculations do not take account of any other (potential) revenues from the sale of energy origin certificates. Keywords: Gas turbine air bottoming cycle, Air bottoming cycle, Gas turbine, GT10

  3. K-FIX(GT): A computer program for modeling the expansion phase of steam explosions within complex three dimensional cavities

    International Nuclear Information System (INIS)

    Hyder, M.L.; Farawila, Y.M.; Abdel-Khalik, S.I.; Halvorson, P.J.

    1992-05-01

    In the development of the Severe Accident Analysis Program for the Savannah River production reactors, it was recognized that certain accidents have the potential for causing damaging steam explosions. The massive SRS reactor buildings are likely to withstand any imaginable steam explosion. However, reactor components and building structures including hatches, ventilation ducts, etc., could be at risk if such an explosion occurred. No tools were available to estimate the effects of such explosions on actual structures. To meet this need, the Savannah River Laboratory contracted with the Georgia Institute of Technology Research Institute for development of a computer-based calculational tool for estimating the effects of steam explosions. The goal for this study was to develop a computer code that could be used parametrically to predict the effects of various steam explosions on their surroundings. This would be able to predict whether a steam explosion of a given magnitude would be likely to fail a particular structure. This would require, of course, that the magnitude of the explosion be specified through some combination of judgment and calculation. The requested code, identified as the K-FIX(GT) code, was developed and delivered by the contractor, along with extensive documentation. The several individual reports that constitute the documentation are each being issued as a separate WSRC report. Documentation includes several model calculations, and representation of these in graphic form. This report gives detailed instructions for the use of the code, including identification of all input parameters required

  4. Dynamic modelling of nuclear steam generators

    International Nuclear Information System (INIS)

    Kerlin, T.W.; Katz, E.M.; Freels, J.; Thakkar, J.

    1980-01-01

    Moving boundary, nodal models with dynamic energy balances, dynamic mass balances, quasi-static momentum balances, and an equivalent single channel approach have been developed for steam generators used in nuclear power plants. The model for the U-tube recirculation type steam generator is described and comparisons are made of responses from models of different complexity; non-linear versus linear, high-order versus low order, detailed modeling of the control system versus a simple control assumption. The results of dynamic tests on nuclear power systems show that when this steam generator model is included in a system simulation there is good agreement with actual plant performance. (author)

  5. Feasibility study for SOFC-GT hybrid locomotive power: Part I. Development of a dynamic 3.5 MW SOFC-GT FORTRAN model

    OpenAIRE

    Martinez, AS; Brouwer, J; Samuelsen, GS

    2012-01-01

    This work presents the development of a dynamic SOFC-GT hybrid system model applied to a long-haul freight locomotive in operation. Given the expectations of the rail industry, the model is used to develop a preliminary analysis of the proposed system's operational capability on conventional diesel fuel as well as natural gas and hydrogen as potential fuels in the future. It is found that operation of the system on all three of these fuels is feasible with favorable efficiencies and reasonabl...

  6. Oman Drilling Project GT3 site survey: dynamics at the roof of an oceanic magma chamber

    Science.gov (United States)

    France, L.; Nicollet, C.; Debret, B.; Lombard, M.; Berthod, C.; Ildefonse, B.; Koepke, J.

    2017-12-01

    Oman Drilling Project (OmanDP) aims at bringing new constraints on oceanic crust accretion and evolution by drilling Holes in the whole ophiolite section (mantle and crust). Among those, operations at GT3 in the Sumail massif drilled 400 m to sample the dike - gabbro transition that corresponds to the top (gabbros) and roof (dikes) of the axial magma chamber, an interface where hydrothermal and magmatic system interacts. Previous studies based on oceanic crust formed at present day fast-spreading ridges and preserved in ophiolites have highlighted that this interface is a dynamic horizon where the axial melt lens that top the main magma chamber can intrude, reheat, and partially assimilate previously hydrothermally altered roof rocks. Here we present the preliminary results obtained in GT3 area that have allowed the community to choose the drilling site. We provide a geological and structural map of the area, together with new petrographic and chemical constraints on the dynamics of the dike - gabbro transition. Our new results allow us to quantify the dynamic processes, and to propose that 1/ the intrusive contact of the varitextured gabbro within the dikes highlights the intrusion of the melt lens top in the dike rooting zone, 2/ both dikes and previously crystallized gabbros are reheated, and recrystallized by underlying melt lens dynamics (up to 1050°C, largely above the hydrous solidus temperature of altered dikes and gabbros), 3/ the reheating range can be > 200°C, 4/ the melt lens depth variations for a given ridge position is > 200m, 5/ the reheating stage and associated recrystallization within the dikes occurred under hydrous conditions, 6/ the reheating stage is recorded at the root zone of the sheeted dike complex by one of the highest stable conductive thermal gradient ever recorded on Earth ( 3°C/m), 7/ local chemical variations in recrystallized dikes and gabbros are highlighted and used to quantify crystallization and anatectic processes, and the

  7. Dynamic analysis of CHASNUPP steam generator structure during shipping

    International Nuclear Information System (INIS)

    Han Liangbi; Xu Jinkang; Zhou Meiwu; He Yinbiao

    1998-07-01

    The dynamic analysis of CHASNUPP steam generator during shipping is described, including the simplified mathematical model, acceleration power spectrum of ocean wave induced random vibration, the dynamic analysis of steam generator structure under random loading, the applied computer code and calculated results

  8. Feasibility study for SOFC-GT hybrid locomotive power: Part I. Development of a dynamic 3.5 MW SOFC-GT FORTRAN model

    Science.gov (United States)

    Martinez, Andrew S.; Brouwer, Jacob; Samuelsen, G. Scott

    2012-09-01

    This work presents the development of a dynamic SOFC-GT hybrid system model applied to a long-haul freight locomotive in operation. Given the expectations of the rail industry, the model is used to develop a preliminary analysis of the proposed system's operational capability on conventional diesel fuel as well as natural gas and hydrogen as potential fuels in the future. It is found that operation of the system on all three of these fuels is feasible with favorable efficiencies and reasonable dynamic response. The use of diesel fuel reformate in the SOFC presents a challenge to the electrochemistry, especially as it relates to control and optimization of the fuel utilization in the anode compartment. This is found to arise from the large amount of carbon monoxide in diesel reformate that is fed to the fuel cell, limiting the maximum fuel utilization possible. This presents an opportunity for further investigations into carbon monoxide electrochemical oxidation and/or system integration studies where the efficiency of the fuel reformer can be balanced against the needs of the SOFC.

  9. Dynamics and control modeling of the closed-cycle gas turbine (GT-HTGR) power plant

    International Nuclear Information System (INIS)

    Bardia, A.

    1980-02-01

    The simulation if presented for the 800-MW(e) two-loop GT-HTGR plant design with the REALY2 transient analysis computer code, and the modeling of control strategies called for by the inherently unique operational requirements of a multiple loop GT-HTGR is described. Plant control of the GT-HTGR is constrained by the nature of its power conversion loops (PCLs) in which the core cooling flow and the turbine flow are directly related and thus changes in flow affect core cooling as well as turbine power. Additionally, the high thermal inertia of the reactor core precludes rapid changes in the temperature of the turbine inlet flow

  10. Dynamic instability forecasting for through-out sodium steam generators

    International Nuclear Information System (INIS)

    Aleksandrov, V.V.; Rassokhin, N.G.

    1985-01-01

    Simplified technique for determining boundaries of dynamic instability of through-out sodium steam generators is presented. The technique is based on the application of autoresonance concept to autooscillating model of dynamic instability of a steam-generating channel. Estimated model parameters and basic investigational results for different conditions are given. Assessment is performed according to the instability degree. Use of the technique is effective for multiversion studying of SG design at early designing stages

  11. Conformational analysis of GT1B ganglioside and its interaction with botulinum neurotoxin type B: a study by molecular modeling and molecular dynamics.

    Science.gov (United States)

    Venkateshwari, Sureshkumar; Veluraja, Kasinadar

    2012-01-01

    The conformational property of oligosaccharide GT1B in aqueous environment was studied by molecular dynamics (MD) simulation using all-atom model. Based on the trajectory analysis, three prominent conformational models were proposed for GT1B. Direct and water-mediated hydrogen bonding interactions stabilize these structures. The molecular modeling and 15 ns MD simulation of the Botulinum Neuro Toxin/B (BoNT/B) - GT1B complex revealed that BoNT/B can accommodate the GT1B in the single binding mode. Least mobility was seen for oligo-GT1B in the binding pocket. The bound conformation of GT1B obtained from the MD simulation of the BoNT/B-GT1B complex bear a close conformational similarity with the crystal structure of BoNT/A-GT1B complex. The mobility noticed for Arg 1268 in the dynamics was accounted for its favorable interaction with terminal NeuNAc. The internal NeuNAc1 tends to form 10 hydrogen bonds with BoNT/B, hence specifying this particular site as a crucial space for the therapeutic design that can restrict the pathogenic activity of BoNT/B.

  12. Dynamic and control of a once through steam generator

    International Nuclear Information System (INIS)

    Gomes, Arivaldo Vicente

    1979-01-01

    This paper presents a non linear distributed parameter model for the dynamics and feedback control of a large countercurrent heat exchanger used as a once through steam generator for a breeder reactor power plant. A convergent, implicit method has been developed to solve simultaneously the equations of conservation of mass, momentum and energy. The model, applicable to heat exchanger systems in general, has been used specifically to study the performance of a once-through steam generator with respect to its load following ability and stability of throttle steam temperature and pressure. (author)

  13. Linear Dynamics Model for Steam Cooled Fast Power Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Vollmer, H

    1968-04-15

    A linear analytical dynamic model is developed for steam cooled fast power reactors. All main components of such a plant are investigated on a general though relatively simple basis. The model is distributed in those parts concerning the core but lumped as to the external plant components. Coolant is considered as compressible and treated by the actual steam law. Combined use of analogue and digital computer seems most attractive.

  14. Dynamic simulation of steam generator failures

    Energy Technology Data Exchange (ETDEWEB)

    Meister, G [Institut fuer Nukleare Sicherheitsforschung, Kernforschungsanlage Juelich GmbH, Juelich (Germany)

    1988-07-01

    A computer program will be described which is capable to simulate severe transients in a gas heated steam generator. Such transients may arise in the safety analysis of accidents resulting from failures in the heat removal system of an HTGR power plant. Important failure modes which have to be considered are ruptures of one or more steam generator tubes leading to water or steam ejection into the primary system or anomalous operating conditions which my cause damage due to excessive thermal stress. Examples are the complete dryout as a consequence of feedwater interrupt in connection with continuing gas heating and the reflooding of the secondary channel with cold feedwater after dryout. The steam generator program which is capable to simulate accidents of this type is written as a module which can be implemented into a program system fur the simulation of the total heat rejection system. It based on an advanced mathematical model for the two phase flow taking deviations from thermal equilibrium into account. Mass, energy and momentum balances for the primary and secondary fluid and the heat diffusion equations for the heat exchanging wall form a system of coupled differential equations which is solved numerically by an algorithm which is stiffly stable and suppresses effectively oscillations of numerical origin. Results of the simulation of transients of the type mentioned above will be presented and discussed. (author)

  15. Dynamic simulation of steam generator failures

    International Nuclear Information System (INIS)

    Meister, G.

    1988-01-01

    A computer program will be described which is capable to simulate severe transients in a gas heated steam generator. Such transients may arise in the safety analysis of accidents resulting from failures in the heat removal system of an HTGR power plant. Important failure modes which have to be considered are ruptures of one or more steam generator tubes leading to water or steam ejection into the primary system or anomalous operating conditions which my cause damage due to excessive thermal stress. Examples are the complete dryout as a consequence of feedwater interrupt in connection with continuing gas heating and the reflooding of the secondary channel with cold feedwater after dryout. The steam generator program which is capable to simulate accidents of this type is written as a module which can be implemented into a program system fur the simulation of the total heat rejection system. It based on an advanced mathematical model for the two phase flow taking deviations from thermal equilibrium into account. Mass, energy and momentum balances for the primary and secondary fluid and the heat diffusion equations for the heat exchanging wall form a system of coupled differential equations which is solved numerically by an algorithm which is stiffly stable and suppresses effectively oscillations of numerical origin. Results of the simulation of transients of the type mentioned above will be presented and discussed. (author)

  16. The effect of S-substitution at the O6-guanine site on the structure and dynamics of a DNA oligomer containing a G:T mismatch.

    Directory of Open Access Journals (Sweden)

    Elaine Ann Moore

    Full Text Available The effect of S-substitution on the O6 guanine site of a 13-mer DNA duplex containing a G:T mismatch is studied using molecular dynamics. The structure, dynamic evolution and hydration of the S-substituted duplex are compared with those of a normal duplex, a duplex with S-substitution on guanine, but no mismatch and a duplex with just a G:T mismatch. The S-substituted mismatch leads to cell death rather than repair. One suggestion is that the G:T mismatch recognition protein recognises the S-substituted mismatch (GS:T as G:T. This leads to a cycle of futile repair ending in DNA breakage and cell death. We find that some structural features of the helix are similar for the duplex with the G:T mismatch and that with the S-substituted mismatch, but differ from the normal duplex, notably the helical twist. These differences arise from the change in the hydrogen-bonding pattern of the base pair. However a marked feature of the S-substituted G:T mismatch duplex is a very large opening. This showed considerable variability. It is suggested that this enlarged opening would lend support to an alternative model of cell death in which the mismatch protein attaches to thioguanine and activates downstream damage-response pathways. Attack on the sulphur by reactive oxygen species, also leading to cell death, would also be aided by the large, variable opening.

  17. ORTURB, HTGR Steam Turbine Dynamic for FSV Reactor

    International Nuclear Information System (INIS)

    Conklin, J.C.

    2001-01-01

    1 - Description of program or function: ORTURB was written specifically to calculate the dynamic behavior of the Fort St. Vrain (FSV) High- Temperature Gas-Cooled Reactor (HTGR) steam turbines. The program is divided into three main parts: the driver subroutine; turbine subroutines to calculate the pressure-flow balance of the high-, intermediate-, and low-pressure turbines; and feedwater heater subroutines. 2 - Method of solution: The program uses a relationship derived for ideal gas flow in an iterative fashion that minimizes computational time to determine the pressure and flow in the FSV steam turbines as a function of plant transient operating conditions. An important computer modeling characteristic, unique to FSV, is that the high-pressure turbine exhaust steam is used to drive the reactor core coolant circulators prior to entering the reheater. A feedwater heater dynamic simulation model utilizing seven state variables for each of the five heaters is included in the ORTURB computer simulation of the regenerative Rankine cycle steam turbines. The seven temperature differential equations are solved at each time- step using a matrix exponential method. 3 - Restrictions on the complexity of the problem: The turbine shaft is assumed to rotate at a constant (rated) speed of 3600 rpm. Energy and mass storage of steam in the high-, intermediate-, and low-pressure turbines is assumed to be negligible. These limitations exclude the use of ORTURB during a turbine transient such as startup from zero power or very low turbine flows

  18. Modeling and dynamic simulation of U-tube steam generator

    International Nuclear Information System (INIS)

    Cui Zhenghua; Jia Dounan; Chen Xuejun; Yu Erjun

    1992-01-01

    An accurate and simple dynamic mathematical model of U-tube steam generator is presented. It is solved by Adams method and Gear method respectively. The results of this model are in good agreements with that of Kerlin's model which has been validated by the tests. And the two calculating methods are compared

  19. Dynamic computer simulation of the Fort St. Vrain steam turbines

    International Nuclear Information System (INIS)

    Conklin, J.C.

    1983-01-01

    A computer simulation is described for the dynamic response of the Fort St. Vrain nuclear reactor regenerative intermediate- and low-pressure steam turbines. The fundamental computer-modeling assumptions for the turbines and feedwater heaters are developed. A turbine heat balance specifying steam and feedwater conditions at a given generator load and the volumes of the feedwater heaters are all that are necessary as descriptive input parameters. Actual plant data for a generator load reduction from 100 to 50% power (which occurred as part of a plant transient on November 9, 1981) are compared with computer-generated predictions, with reasonably good agreement

  20. A mathematical model of steam-drum dynamics

    International Nuclear Information System (INIS)

    Moeck, E.O.; Hinds, H.W.

    1976-12-01

    Mathematical equations describing the dynamic behaviour of pressure, water mass, etc. in a steam drum are derived from basic principles. The resultant model includes such effects as steam superheating and water subcooling as well as spontaneous flashing of liquid and condensation of vapour. Experimental data from a pressurizer are adequately predicted by the model. The pressure rise following a turbine trip can be predicted by the isentropic-compression model but not by the thermodynamic-equilibrium model. The equations are individually linearized and implemented on an analog computer in such a way that their non-linear behaviour is retained for small-perturbation studies. (author)

  1. Steam generator fitted with a dynamic draining device

    International Nuclear Information System (INIS)

    Chaix, J.E.

    1982-01-01

    This generator has, at its upper part, at least one drying structure for holding the water carried with the steam and communicating at its lower part with at least one discharge pipe for draining off the water, each pipe communicating with a dynamic draining device capable of creating a depression in order to suck up the water contained in the drying structure. Application is for pressurized water nuclear reactors [fr

  2. DYNAM, Once Through Boiling Flow with Steam Superheat, Laplace Transformation

    International Nuclear Information System (INIS)

    Schlueter, G.; Efferding, L.E.

    1973-01-01

    1 - Description of problem or function: DYNAM performs a dynamic analysis of once-through boiling flow oscillations with steam superheat. The model describing the superheat regime (single- phase, variable density fluid) for subcritical pressure operation is also applicable to the study of once-through operation using supercritical pressure water. 2 - Method of solution: Linearized partial differential conservation equations are solved using Laplace transformation of the temporal terms and integration of the spatial variations. DYNAM is written in complex variable notation. 3 - Restrictions on the complexity of the problem - Maxima of: 30 intervals used to describe the power distribution in the non-boiling and boiling regions, 29 boiling nodes, 7 intervals and corresponding friction multipliers read in per case, 14 exit qualities read in per case, 40 superheat nodes, 10 coefficients read in for the phi 2 vs, x-polynomial fit, 48 frequencies at which open-loop frequency response is desired, 48 frequencies at which signal output is desired

  3. Dynamic Modeling of Steam Condenser and Design of PI Controller Based on Grey Wolf Optimizer

    OpenAIRE

    Shu-Xia Li; Jie-Sheng Wang

    2015-01-01

    Shell-and-tube condenser is a heat exchanger for cooling steam with high temperature and pressure, which is one of the main kinds of heat exchange equipment in thermal, nuclear, and marine power plant. Based on the lumped parameter modeling method, the dynamic mathematical model of the simplified steam condenser is established. Then, the pressure PI control system of steam condenser based on the Matlab/Simulink simulation platform is designed. In order to obtain better performance, a new meta...

  4. Dynamic simulation of a steam generator by neural networks

    International Nuclear Information System (INIS)

    Masini, R.; Padovani, E.; Ricotti, M.E.; Zio, E.

    1999-01-01

    Numerical simulation by computers of the dynamic evolution of complex systems and components is a fundamental phase of any modern engineering design activity. This is of particular importance for risk-based design projects which require that the system behavior be analyzed under several and often extreme conditions. The traditional methods of simulation typically entail long, iterative, processes which lead to large simulation times, often exceeding the transients real time. Artificial neural networks (ANNs) may be exploited in this context, their advantages residing mainly in the speed of computation, in the capability of generalizing from few examples, in the robustness to noisy and partially incomplete data and in the capability of performing empirical input-output mapping without complete knowledge of the underlying physics. In this paper we present a novel approach to dynamic simulation by ANNs based on a superposition scheme in which a set of networks are individually trained, each one to respond to a different input forcing function. The dynamic simulation of a steam generator is considered as an example to show the potentialities of this tool and to point out the difficulties and crucial issues which typically arise when attempting to establish an efficient neural network simulator. The structure of the networks system is such to feedback, at each time step, a portion of the past evolution of the transient and this allows a good reproduction of also non-linear dynamic behaviors. A nice characteristic of the approach is that the modularization of the training reduces substantially its burden and gives this neural simulation tool a nice feature of transportability. (orig.)

  5. Influence of steam parameters on static and dynamic characteristics of labyrinth seal

    Directory of Open Access Journals (Sweden)

    HE Wenqiang

    2017-10-01

    Full Text Available [Objectives] In order to study the influence of working medium parameters on the static and dynamic characteristics of seals in turbomachinery,[Methods] a three-dimensional model of a labyrinth seal was created, and air and steam were applied in the numerical simulation. The Computational Fluid Dynamics (CFD method and a rotating frame were applied to analyze the influence of different steam parameters on the leakage characteristics and dynamic characteristic coefficients.[Results] The results show that great differences in leakage flow rate are apparent under different air and steam conditions, and the fluid-induced force shows linear and nonlinear variation with the increasing whirl speed. When the steam temperature increases, the system stability decreases as the dynamic characteristic coefficients change.[Conclusions] In consequence, working medium parameters are of great significance for turbine stability, and the influence of working medium parameters on the static and dynamic characteristics of seals should be given great attention in practical application.

  6. GT-MHR project

    International Nuclear Information System (INIS)

    Kiryushin, A.; Kodochigov, N.

    2002-01-01

    The paper presents new generation reactor - modular helium reactor with gas turbine (GT-MHR), which satisfies the requirements of the developing nuclear power. The paper describes the reactor plant and peculiarities of GT-MHR technical concept, such as high efficiency (about 48%) of electric power generation, increased safety of the plant, etc. The technologies, which are the innovative essence of GT-MHR project, are: (1) fuel in the form of fuel particles with multi-layer ceramic coatings which confine fission products at high temperatures (of about 1600 deg.); (2) large gas turbines; (3) single-shaft vertical turbomachine design; (4) electromagnetic bearings; (5) high-effective compact heat exchangers. Main technical and economical indices of GT-MHR project are presented. (author)

  7. Dynamic response of the EBR-II secondary sodium system to postulated leaks of steam and water into sodium

    International Nuclear Information System (INIS)

    Srinivas, S.; Chopra, P.S.; Stone, C.C.

    1976-01-01

    The paper presents evaluations of the dynamic response of a steam generator system to postulated leaks of steam and water into sodium. This work is part of a comprehensive fail-safe analysis of the EBR-II steam generator system

  8. Dynamic underground stripping: steam and electric heating for in situ decontamination of soils and groundwater

    Science.gov (United States)

    Daily, William D.; Ramirez, Abelardo L.; Newmark, Robin L.; Udell, Kent; Buetnner, Harley M.; Aines, Roger D.

    1995-01-01

    A dynamic underground stripping process removes localized underground volatile organic compounds from heterogeneous soils and rock in a relatively short time. This method uses steam injection and electrical resistance heating to heat the contaminated underground area to increase the vapor pressure of the contaminants, thus speeding the process of contaminant removal and making the removal more complete. The injected steam passes through the more permeable sediments, distilling the organic contaminants, which are pumped to the surface. Large electrical currents are also applied to the contaminated area, which heat the impermeable subsurface layers that the steam has not penetrated. The condensed and vaporized contaminants are withdrawn by liquid pumping and vacuum extraction. The steam injection and electrical heating steps are repeated as necessary. Geophysical imaging methods can be used to map the boundary between the hot, dry, contamination-free underground zone and the cool, damp surrounding areas to help monitor the dynamic stripping process.

  9. Main: GT1CONSENSUS [PLACE

    Lifescience Database Archive (English)

    Full Text Available m of GT-1 may be achieved through direct interaction between TFIIA and GT-1; Binding of GT-1-like factors to the PR-1a promoter influ...ences the level of SA-inducible gene expression; GT-1; light; TATA; TFIIA; TBP; HR;

  10. Preliminary biological sampling of GT3 and BT1 cores and the microbial community dynamics of existing subsurface wells

    Science.gov (United States)

    Kraus, E. A.; Stamps, B. W.; Rempfert, K. R.; Ellison, E. T.; Nothaft, D. B.; Boyd, E. S.; Templeton, A. S.; Spear, J. R.

    2017-12-01

    Subsurface microbial life is poorly understood but potentially very important to the search for life on other planets as well as increasing our understanding of Earth's geobiological processes. Fluids and rocks of actively serpentinizing subsurface environments are a recent target of biological study due to their apparent ubiquity across the solar system. Areas of serpentinization can contain high concentrations of molecular hydrogen, H2, that can serve as the dominant fuel source for subsurface microbiota. Working with the Oman Drilling Project, DNA and RNA were extracted from fluids of seven alkaline wells and two rock cores from drill sites GT3 and BT1 within the Samail ophiolite. DNA and cDNA (produced via reverse transcription from the recovered RNA) were sequenced using universal primers to identify microbial life across all three domains. Alkaline subsurface fluids support a microbial community that changes with pH and host-rock type. In peridotite with pH values of >11, wells NSHQ 14 and WAB 71 have high relative abundances of Meiothermus, Methanobacterium, the family Nitrospiraceae, and multiple types of the class Dehalococcoidia. While also hosted in peridotite but at pH 8.5, wells WAB 104 and 105 have a distinct, more diverse microbial community. This increased variance in community make-up is seen in wells that sit near/at the contact of gabbro and peridotite formations as well. Core results indicate both sampled rock types host a very low biomass environment subject to multiple sources of contamination during the drilling process. Suggestions for contaminant reduction, such as having core handlers wear nitrile gloves and flame-sterilizing the outer surfaces of core rounds for biological sampling, would have minimal impact to overall ODP coreflow and maximize the ability to better understand in situ microbiota in this low-biomass serpentinizing subsurface environment. While DNA extraction was successful with gram amounts of crushed rock, much can be

  11. Effect of heat transfer tube leak on dynamic characteristic of steam generator

    International Nuclear Information System (INIS)

    Sun Baozhi; Shi Jianxin; Li Na; Zheng Lusong; Liu Shanghua; Lei Yu

    2015-01-01

    Taking the steam generator of Daya Bay Nuclear Power Station as the research object, one-dimensional dynamic model of the steam generator based on drift flux theory and leak model of heat transfer tube were established. Steady simulation of steam generator under different conditions was carried out. Based on verifying the drift flux model and leak model of heat transfer tube, the effect of leak location and flow rate under different conditions on steam generator's key parameters was studied. The results show that the drift flux model and leak model can reflect the law of key parameter change accurately such as vapor mass fraction and steam pressure under different leak cases. The variation of the parameters is most apparent when the leak is at the entrance of boiling section and vapor mass fraction varies from 0.261 to 0.163 when leakage accounts for 5% of coolant flow rate. The successful prediction of the effect of heat transfer tube leak on dynamic characteristics of the steam generator based on drift flux theory supplies some references for monitoring and taking precautionary measures to prevent heat transfer tube leak accident. (authors)

  12. Dynamic Characteristics of Steam Generator Tubes with Defect due to Wear

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sangjin; Rhee, Huinam [Sunchon National Univ., Sunchon (Korea, Republic of); Yoon, Doo Byung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    These defects may affect the dynamic characteristics of tubes, and therefore, the vibrational behavior of the tube due to flow-induced loads can be varied. Change in the vibrational response of a tube may result in different wear characteristics from the design condition, which must be checked for both safety and economic point of view. This paper deals with the study on the effect of wears or cracks on the dynamic characteristics of steam generator tubes using finite element analysis. In this paper the effect of defects on the surface due to wear on the variation of dynamic characteristics of steam generator tubes was studied using the finite element analysis. The changes of natural frequencies and mode shapes can directly affect the flow-induced vibration response characteristics, therefore, they must be evaluated appropriately. The results in this study can be a good basis to estimate the FIV characteristics of the steam generator tubes having defects such as wear or crack.

  13. Dynamic simulation of a furnace of steam reforming of natural gas

    International Nuclear Information System (INIS)

    Acuna, A; Fuentes, C; Smith, C A

    1999-01-01

    Steam reforming of natural gas is a very important industrial process in refineries and ammonia and methanol plants. Hydrogen is produced by reforming methane with steam. This hydrogen is essential in the hydro-treating process in the refineries thus, it is important to supervise and control the performance of the hydrogen plant. Mathematical models of refineries and chemical plants are used to simulate the behavior of the process units. However, the models especially of reactors like reformers are not very reliable. This paper presents a dynamic model of a furnace-reactor. The simulation results are validated with industrial data

  14. Dynamic modeling and simulation of EBR-II steam generator system

    International Nuclear Information System (INIS)

    Berkan, R.C.; Upadhyaya, B.R.

    1989-01-01

    This paper presents a low order dynamic model of the Experimental breeder Reactor-II (EBR-II) steam generator system. The model development includes the application of energy, mass and momentum balance equations in state-space form. The model also includes a three-element controller for the drum water level control problem. The simulation results for low-level perturbations exhibit the inherently stable characteristics of the steam generator. The predictions of test transients also verify the consistency of this low order model

  15. Real-time dynamic analysis for complete loop of direct steam generation solar trough collector

    International Nuclear Information System (INIS)

    Guo, Su; Liu, Deyou; Chu, Yinghao; Chen, Xingying; Shen, Bingbing; Xu, Chang; Zhou, Ling; Wang, Pei

    2016-01-01

    Highlights: • A nonlinear distribution parameter dynamic model has been developed. • Real-time local heat transfer coefficient and friction coefficient are adopted. • The dynamic behavior of the solar trough collector loop are simulated. • High-frequency chattering of outlet fluid flow are analyzed and modeled. • Irradiance disturbance at subcooled water region generates larger influence. - Abstract: Direct steam generation is a potential approach to further reduce the levelized electricity cost of solar trough. Dynamic modeling of the collector loop is essential for operation and control of direct steam generation solar trough. However, the dynamic behavior of fluid based on direct steam generation is complex because of the two-phase flow in the pipeline. In this work, a nonlinear distribution parameter model has been developed to model the dynamic behaviors of direct steam generation parabolic trough collector loops under either full or partial solar irradiance disturbance. Compared with available dynamic model, the proposed model possesses two advantages: (1) real-time local values of heat transfer coefficient and friction resistance coefficient, and (2) considering of the complete loop of collectors, including subcooled water region, two-phase flow region and superheated steam region. The proposed model has shown superior performance, particularly in case of sensitivity study of fluid parameters when the pipe is partially shaded. The proposed model has been validated using experimental data from Solar Thermal Energy Laboratory of University of New South Wales, with an outlet fluid temperature relative error of only 1.91%. The validation results show that: (1) The proposed model successfully outperforms two reference models in predicting the behavior of direct steam generation solar trough. (2) The model theoretically predicts that, during solar irradiance disturbance, the discontinuities of fluid physical property parameters and the moving back and

  16. Dynamics of mineral N, water-soluble carbon and potential nitrification in band-steamed arable soil

    DEFF Research Database (Denmark)

    Elsgaard, Lars

    2010-01-01

    the effect of band-steaming on N and C dynamics in a sandy loam soil that was steamed in situ to maximal temperatures of 70-90°C using a prototype band-steamer. Soil samples (0-5 cm depth) were collected during 90 days from band-steamed soil, undisturbed control soil, and control soil treated just...

  17. Dynamic Modeling of Steam Condenser and Design of PI Controller Based on Grey Wolf Optimizer

    Directory of Open Access Journals (Sweden)

    Shu-Xia Li

    2015-01-01

    Full Text Available Shell-and-tube condenser is a heat exchanger for cooling steam with high temperature and pressure, which is one of the main kinds of heat exchange equipment in thermal, nuclear, and marine power plant. Based on the lumped parameter modeling method, the dynamic mathematical model of the simplified steam condenser is established. Then, the pressure PI control system of steam condenser based on the Matlab/Simulink simulation platform is designed. In order to obtain better performance, a new metaheuristic intelligent algorithm, grey wolf optimizer (GWO, is used to realize the fine-tuning of PI controller parameters. On the other hand, the Z-N engineering tuning method, genetic algorithm, and particle swarm algorithm are adopted for tuning PI controller parameters and compared with GWO algorithm. Simulation results show that GWO algorithm has better control performance than other four algorithms.

  18. Dynamic characteristics of steam generator U-tubes with defect

    International Nuclear Information System (INIS)

    Jo, Jong Chull; Jhung, Myung Jo; Kim, Woong Sik; Kim, Hho Jung

    2005-01-01

    This study investigates the fluid elastic instability characteristics of steam generator (SG) U-tubes with defect and the safety assessment of the potential for fretting-wear damages caused by foreign object in operating nuclear power plants. To get the natural frequency, corresponding mode shape and participation factor, modal analyses are performed for the U-tubes either with axial or circumferential flaw with different sizes. Special emphases are on the effects of flaw orientation and size on the modal and instability characteristics of tubes, which are expressed in terms of the natural frequency, corresponding mode shape and stability ratio. Also, the wear rate of U-tube caused by foreign object is calculated using the Archard formula and the remaining life of the tube is predicted, and discussed in this study is the effect of the flow velocity and vibration of the tube on the remaining life of the tube. In addition, addressed in this study is the effect of the internal pressure on the vibration and fretting-wear characteristics of the tube

  19. Development and verification of a space-dependent dynamic model of a natural circulation steam generator

    International Nuclear Information System (INIS)

    Mewdell, C.G.; Harrison, W.C.; Hawley, E.H.

    1980-01-01

    This paper describes the development and verification of a Non-Linear Space-Dependent Dynamic Model of a Natural Circulation Steam Generator typical of boilers used in CANDU nuclear power stations. The model contains a detailed one-dimensional dynamic description of both the primary and secondary sides of an integral pre-heater natural circulation boiler. Two-phase flow effects on the primary side are included. The secondary side uses a drift-flux model in the boiling sections and a detailed non-equilibrium point model for the steam drum. The paper presents the essential features of the final model called BOILER-2, its solution scheme, the RD-12 loop and test boiler, the boiler steady-state and transient experiments, and the comparison of the model predictions with experimental results. (author)

  20. Dynamic model of YGN 3 and 4 steam generators for natural circulation mode

    International Nuclear Information System (INIS)

    Sohn, Jong Joo

    1995-02-01

    A dynamic model for the secondary side of Yonggwang nuclear power plant units 3 and 4 (YGN 3 and 4) steam generator model is developed to improve the accuracy of the present performance analysis code. The new model is based on the one-dimensional three region model to predict the local quality and void fraction distribution along the U-tube length. The local quality concept is used instead of the Wilson bubble rise correlation to simulate the steam generators in the natural circulation mode. The new model can be applicable to the plants in the power operation modes such as load maneuvering transients in which the steam generator internal flow is maintained in the natural circulation mode. To validate the new model, the code predictions are compared with the actual plant data measured for the selected load maneuvering tests performed during the YGN units 3 power ascension test period. The results from the improved model show better agreement with the plant data than those from the present code. Especially, the new model's capability of accurately simulating the steam generator water level behavior during the fast transients such as a large load rejection event is demonstrated

  1. Dynamic load in suppression pool during BWR main steam safety relief valve actuation

    International Nuclear Information System (INIS)

    Tsukada, Hiroshi; Yamaguchi, Hirokatsu; Morita, Terumichi

    1979-01-01

    BWRs are so designed that the exhaust steam from main steam safety relief valves is led to pressure suppression pools, and the steam is condensed in pool water, but at this time, dynamic load seems to arise in the pool water. In Tokai No. 2 Power Station, a Mark-2 containment vessel was adopted to improve the reliability as much as possible and to obtain the design with margin. In this report, the result of actual machine test in Tokai No. 2 Power Station and the method of reducing the load are described. When a relief valve works, the discharge of water in exhaust pipes into a suppression pool, the exhaust of air in exhaust pipes and repeated expansion and contraction of bubbles in pool water, and the exhaust of steam and condensation occur. As for the construction of the suppression pool in Tokai No. 2 Power Station, cross-shaped quencher and the structure with jet deflector were installed. The test plan and the test result with an actual machine are reported. The soundness of the Mark-2 containment vessel and the structures in the pool was proved. The differential pressure acting on the structures was negligibly small. The measured pulsating pressure was in the range from 0.84 to -0.39 kg/cm 2 . (Kako, I.)

  2. Steam drum level dynamics in a multiple loop natural circulation system of a pressure-tube type boiling water reactor

    International Nuclear Information System (INIS)

    Jain, Vikas; Kulkarni, P.P.; Nayak, A.K.; Vijayan, P.K.; Saha, D.; Sinha, R.K.

    2011-01-01

    Highlights: → We have highlighted the problem of drum level dynamics in a multiple loop type NC system using RELAP5 code. → The need of interconnections in steam and liquid spaces close to drum is established. → The steam space interconnections equalize pressure and liquid space interconnections equalize level. → With this scheme, the system can withstand anomalous conditions. → However, the controller is found to be inevitable for inventory balance. - Abstract: Advanced Heavy Water Reactor (AHWR) is a pressure tube type boiling water reactor employing natural circulation as the mode of heat removal under all the operating conditions. Main heat transport system (MHTS) of AHWR is essentially a multi-loop natural circulation system with all the loops connected to each other. Each loop of MHTS has a steam drum that provides for gravity based steam-water separation. Steam drum level is a very critical parameter especially in multi-loop natural circulation systems as large departures from the set point may lead to ineffective separation of steam-water or may affect the driving head. However, such a system is susceptible to steam drum level anomalies under postulated asymmetrical operating conditions among the different quadrants of the core like feedwater flow distribution anomaly among the steam drums or power anomaly among the core quadrants. Analyses were carried out to probe such scenarios and unravel the underlying dynamics of steam drum level using system code RELAP5/Mod3.2. In addition, a scheme to obviate such problem in a passive manner without dependence on level controller was examined. It was concluded that steam drums need to be connected in the liquid as well as steam space to make the system tolerant to asymmetrical operating conditions.

  3. Dynamic study of steam generation from low-grade waste heat in a zeolite–water adsorption heat pump

    International Nuclear Information System (INIS)

    Xue, Bing; Meng, Xiangrui; Wei, Xinli; Nakaso, Koichi; Fukai, Jun

    2015-01-01

    A novel zeolite–water adsorption heat pump system based on a direct-contact heat exchange method to generate steam from low-grade waste gas and water has been proposed and examined experimentally. Superheated steam (200 °C, 0.1 MPa) is generated from hot water (70–80 °C) and dry air (100–130 °C). A dynamic model for steam generation process is developed to describe local mass and heat transfer. This model features a three-phase calculation and a moving water–gas interface. The calculations are carried out in the zeolite–water and zeolite–gas regions. Model outputs are compared with experimental results for validation. The thermal response inside the reactor and mass of steam generated is well predicted. Numerical results show that preheat process with low-temperature steam is an effective method to achieve local equilibrium quickly, thus generation process is enhanced by prolonging the time and increasing mass of the generated steam. Besides, high-pressure steam generation up to 0.5 MPa is possible from the validated dynamic model. Future work could be emphasized on enhancing high-pressure steam generation with preheat process or mass recovery operation

  4. Preliminary safety evaluation of the Gas Turbine-Modular Helium Reactor (GT-MHR)

    International Nuclear Information System (INIS)

    Dunn, T.D.; Lommers, L.J.; Tangirala, V.E.

    1994-04-01

    A qualitative comparison between the safety characteristics of the Gas Turbine-Modular Helium Reactor (GT-MHR) and those of the steam cycle shows that the two designs achieve equivalent levels of overall safety performance. This comparison is obtained by applying the scaling laws to detailed steam-cycle computations as well as the conclusions obtained from preliminary GT-MHR model simulations. The gas turbine design is predicted to be superior for some event categories, while the steam cycle design is better for others. From a safety perspective, the GT-MHR has a modest advantage for pressurized conduction cooldown events. Recent computational simulations of 102 column, 550 MW(t) GT-MHR during a depressurized conduction cooldown show that peak fuel temperatures are within the limits. The GT-MHR has a significantly lower risk due to water ingress events under operating conditions. Two additional scenarios, namely loss of load event and turbine deblading event that are specific to the GT-MHR design are discussed. Preliminary evaluation of the GT-MHR's safety characteristics indicate that the GT-MHR can be expected to satisfy or exceed its safety requirements

  5. A gas dynamic and thermochemical model of steam/sodium microleak phenomena

    International Nuclear Information System (INIS)

    Perkins, R.; Airey, R.; Daniels, L.C.

    1985-06-01

    Conflicting findings have been reported by 3 UK laboratories for the blockage or rapid escalation of steam/sodium microleaks. In an earlier paper it was shown that this discrepancy could be resolved through the influence on the steam flow of the geometry of the leak paths; the geometry being dependent upon the method of manufacture. The application of gas dynamics and thermochemical methods could account for the rapid escalation of some leaks in terms of the presence of shock waves in the gas flow within the leak path. In this paper the gas dynamic and thermochemical theories are re-stated and a series of leak experiments conducted to test the validity of the theory is described. The theory predicts that for some leaks of variable area of cross-section the blockage/escalation behaviour is determined by small changes in the sodium-side pressure; this effect was found and is discussed as a validation of the theory. Other aspects of leak phenomena are discussed and conclusions are drawn with emphasis on implications for further programmes of leak study and for leaks in LMFBR steam generators in service. (author)

  6. Numerical fluid dynamics calculations of nonequilibrium steam-water flows with entrained droplets

    International Nuclear Information System (INIS)

    Williams, K.A.

    1984-01-01

    The present work has developed a computational fluid dynamics formulation that efficiently solves the conservation laws for a vapor field, a continuous liquid field, and two dispersed droplet fields. The thermal-hydraulic effects resulting from the exchange of mass, momentum and energy between the vapor and the dispersed droplet phases has been accurately modeled. This work is an advancement of the state-of-the-art for engineering analyses of nonequilibrium steam-water-droplet flows in heated channels. It is particularly applicable for boiling steam-water flows in which it is important to represent the effects of significant thermal nonequilibrium between the vapor and the liquid phases. This work was shown to be in good agreement with unique experimental measurements of significant thermal nonequilibrium between the vapor and dispersed droplets. The tests analyzed covered a range of mass fluxes and wall heating rates, and were all at low pressures where nonequilibrium effects are most pronounced

  7. An analytical formulation of thermodynamic properties of dry and metastable steam suitable for computational fluid dynamics modelling of steam turbine flows

    Czech Academy of Sciences Publication Activity Database

    Hrubý, Jan; Pátek, Jaroslav; Duška, Michal

    2014-01-01

    Roč. 228, č. 2 (2014), s. 120-128 ISSN 0957-6509 R&D Projects: GA AV ČR IAA200760905; GA ČR(CZ) GAP101/11/1593; GA MŠk LG13056 Institutional support: RVO:61388998 Keywords : metastable steam * thermodynamic properties * computational fluid dynamics Subject RIV: BJ - Thermodynamics Impact factor: 0.645, year: 2014 http://pia.sagepub.com/content/228/2.toc

  8. Pipe rupture and steam/water hammer design loads for dynamic analysis of piping systems

    International Nuclear Information System (INIS)

    Strong, B.R. Jr.; Baschiere, R.J.

    1978-01-01

    The design of restraints and protection devices for nuclear Class I and Class II piping systems must consider severe pipe rupture and steam/water hammer loadings. Limited stress margins require that an accurate prediction of these loads be obtained with a minimum of conservatism in the loads. Methods are available currently for such fluid transient load development, but each method is severely restricted as to the complexity and/or the range of fluid state excursions which can be simulated. This paper presents a general technique for generation of pipe rupture and steam/water hammer design loads for dynamic analysis of nuclear piping systems which does not have the limitations of existing methods. Blowdown thrust loadings and unbalanced piping acceleration loads for restraint design of all nuclear piping systems may be found using this method. The technique allows the effects of two-phase distributed friction, liquid flashing and condensation, and the surrounding thermal and mechanical equipment to be modeled. A new form of the fluid momentum equation is presented which incorporates computer generated fluid acceleration histories by inclusion of a geometry integral termed the 'force equivalent area' (FEA). The FEA values permit the coupling of versatile thermal-hydraulic programs to piping dynamics programs. Typical applications of the method to pipe rupture problems are presented and the resultant load histories compared with existing techniques. (Auth.)

  9. Dynamic simulation of pure hydrogen production via ethanol steam reforming in a catalytic membrane reactor

    International Nuclear Information System (INIS)

    Hedayati, Ali; Le Corre, Olivier; Lacarrière, Bruno; Llorca, Jordi

    2016-01-01

    Ethanol steam reforming (ESR) was performed over Pd-Rh/CeO 2 catalyst in a catalytic membrane reactor (CMR) as a reformer unit for production of fuel cell grade pure hydrogen. Experiments were performed at 923 K, 6–10 bar, and fuel flow rates of 50–200 μl/min using a mixture of ethanol and distilled water with steam to carbon ratio of 3. A static model for the catalytic zone was derived from the Arrhenius law to calculate the total molar production rates of ESR products, i.e. CO, CO 2 , CH 4 , H 2 , and H 2 O in the catalytic zone of the CMR (coefficient of determination R 2  = 0.993). The pure hydrogen production rate at steady state conditions was modeled by means of a static model based on the Sieverts' law. Finally, a dynamic model was developed under ideal gas law assumptions to simulate the dynamics of pure hydrogen production rate in the case of the fuel flow rate or the operating pressure set point adjustment (transient state) at isothermal conditions. The simulation of fuel flow rate change dynamics was more essential compared to the pressure change one, as the system responded much faster to such an adjustment. The results of the dynamic simulation fitted very well to the experimental values at P = 7–10 bar, which proved the robustness of the simulation based on the Sieverts' law. The simulation presented in this work is similar to the hydrogen flow rate adjustments needed to set the electrical load of a fuel cell, when fed online by the pure hydrogen generating reformer studied. - Highlights: • Ethanol steam reforming (ESR) experiments were performed in a Pd-Ag membrane reactor. • The model of the catalytic zone of the reactor was derived from the Arrhenius law. • The permeation zone (membrane) was modeled based on the Sieverts' law. • The Sieverts' law model showed good results for the range of P = 7–10 bar. • Pressure and fuel flow rate adjustments were considered for dynamic simulation.

  10. Microalgae fractionation using steam explosion, dynamic and tangential cross-flow membrane filtration.

    Science.gov (United States)

    Lorente, E; Hapońska, M; Clavero, E; Torras, C; Salvadó, J

    2017-08-01

    In this study, the microalga Nannochloropsis gaditana was subjected to acid catalysed steam explosion treatment and the resulting exploded material was subsequently fractionated to separate the different fractions (lipids, sugars and solids). Conventional and vibrational membrane setups were used with several polymeric commercial membranes. Two different routes were followed: 1) filtration+lipid solvent extraction and 2) lipid solvent extraction+filtration. Route 1 revealed to be much better since the used membrane for filtration was able to permeate the sugar aqueous phase and retained the fraction containing lipids; after this, an extraction required a much lower amount of solvent and a better recovering yield. Filtration allowed complete lipid rejection. Dynamic filtration improved permeability compared to the tangential cross-flow filtration. Best membrane performance was achieved using a 5000Da membrane with the dynamic system, obtaining a permeability of 6L/h/m 2 /bar. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Completion of a simulation model for calculation of static and dynamic behaviour of steam generators and its use for a pilot steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Seybold, M

    1979-07-20

    In the present paper, first of all the model concept reported in detail by Schittke is applied to the steady-state predictive calculation of an arbitrarily nested steam generator based on the design data and empirical values on heat discharge and heat transfer. The dynamics of the system are precalculated on the basis of the known steady-state behaviour and with the construction data, that is without experimental identification, according to the Schittke concept. The object for the calculation is a steam generator with once-through forced flow (VDE) which was put at the disposal of the Institute for Process Engineering and Steamboiler Studies. Data for the computer programs were taken only from the construction documents (geometries, nesting etc.) or from design data (thermic parameters). Parallel with the program preparation and the calculation measurements on the experimental plant were planned, adaptations and tests were carried out. The correctness of precalculating a steam generator could then be checked with the experimental plant and by comparison with the results of the measurements.

  12. Independent tube verification and dynamic tracking in et inspection of nuclear steam generator

    International Nuclear Information System (INIS)

    Xiongzi, Li; Zhongxue, Gan; Lance, Fitzgibbons

    2001-01-01

    The full text follows. In the examination of pressure boundary tubes in steam generators of commercial pressurized water nuclear power plants (PWR's), it is critical to know exactly which particular tube is being accessed. There are no definitive landmarks or markings on the individual tubes. Today this is done manually, it is tedious, and interrupts the normal inspection work, and is difficult due to the presence of water on the tube surface, plug ends instead of tube openings in the field of view, and varying lighting quality. In order to eliminate the human error and increase the efficiency of operation, there is a need to identify tube position during the inspection process, independent of robot encoder position and motion. A process based on a Cognex MVS-8200 system and its application function package has been developed to independently identify tube locations. ABB Combustion Engineering Nuclear Power's Outage Services group, USPPL in collaboration with ABB Power Plant Laboratories' Advanced Computers and Controls department has developed a new vision-based Independent Tube Verification system (GENESIS-ITVS-TM ). The system employ's a model-based tube-shape detection algorithm and dynamic tracking methodology to detect the true tool position and its offsets from identified tube location. GENESIS-ITVS-TM is an automatic Independent Tube Verification System (ITVS). Independent tube verification is a tube validation technique using computer vision, and not using any robot position parameters. This process independently counts the tubes in the horizontal and vertical axes of the plane of the steam generator tube sheet as the work tool is moved. Thus it knows the true position in the steam generator, given a known starting point. This is analogous to the operator's method of counting tubes for verification, but it is automated. GENESIS-ITVS-TM works independent of the robot position, velocity, or acceleration. The tube position information is solely obtained from

  13. Dynamic performance investigation of once-through-type steam generator for NPP using a large-scale model

    International Nuclear Information System (INIS)

    Kats, F.M.; Ostrovskij, L.A.; Ehskin, N.B.

    1985-01-01

    An experimental bench is described as well as the results of dynamic performance investigation of mass- and heat transfer of the once-through type steam generator for the NPP with weak superheat. Coolant for the primary and secondary circuit is water. Under investigation conditions the possibility of changin.o primary and secondary circuit temperatures has been supphed as well as the primary circuit flow rate and the secondary circuit pressure changes. Transients for differen.t operating conditions are considered. The possibility for construction of the steam generator automatic control system is based

  14. Computational fluid dynamics validation study of steam condensation on the containment walls

    International Nuclear Information System (INIS)

    Gera, B.; Sharma, P.K.; Singh, R.K.; Vaze, K.K.

    2012-01-01

    In water cooled power reactors, significant quantities of hydrogen could be produced following a severe accident (loss-of-coolant-accident along with non availability of emergency core cooling system). A sound understanding of dispersion, stratification and diffusion of released hydrogen during severe accidents is, therefore, of practical importance and use to better understand the possibility of ignition, combustion and explosion of such releases within the context of containment safety. The presence of air and steam in the containment atmosphere also affects the hydrogen distribution as steam condensation takes place at containment walls in presence of non condensable and bulk of the mixture diffuses towards wall. The application of general purpose CFD codes for the analysis of the hydrogen behaviour within NPP containments during severe accidents has been increasing over past few years. The commercial CFD codes generally do not have built-in steam condensations models. In the present work, the adaptation of a commercial multipurpose code to this kind of problem is explained, i.e. by the implementation of models for steam condensation onto walls in presence of non-condensable gases. Steam condensation was modeled using the Uchida correlation, which was originally developed to be used for 'lumped' (volume-averaged) modeling of steam condensation in the presence of non-condensable gases. The Uchida correlation is based on experiments on natural convection from relatively small vertical plates. The present methodology has been validated against experimental data from the TOSQAN and COPAIN experimental facilities. (orig.)

  15. The influence of selected design and operating parameters on the dynamics of the steam micro-turbine

    Science.gov (United States)

    Żywica, Grzegorz; Kiciński, Jan

    2015-10-01

    The topic of the article is the analysis of the influence of selected design parameters and operating conditions on the radial steam micro-turbine, which was adapted to operate with low-boiling agent in the Organic Rankine Cycle (ORC). In the following parts of this article the results of the thermal load analysis, the residual unbalance and the stiffness of bearing supports are discussed. Advanced computational methods and numerical models have been used. Computational analysis showed that the steam micro-turbine is characterized by very good dynamic properties and is resistant to extreme operating conditions. The prototype of micro-turbine has passed a series of test calculations. It has been found that it can be subjected to experimental research in the micro combined heat and power system.

  16. Asymmetric GT of social networks

    Science.gov (United States)

    Szu, Harold

    2010-04-01

    Web citation indexes are computed according to a data vector X collected from the frequency of user accesses, citations weighted by other sites' popularities, and modified by the financial sponsorship in a proprietary manner. The indexing determining the information to be retrieved by the public should be made responsible transparently in at least two ways. One shall balance the inbound linkages pointed at the specific i-th site called the popularity (see paper for equation) with the outbound linkages (see paper for equation) called the risk factor before the release of new information as environmental impact analysis. The relationship between these two factors cannot be assumed equivalent (undirected) as in the case of many mainstream Graph Theory (GT) models.

  17. Preliminary analysis of the PreFlexMS molten salt once-through steam generator dynamics and control strategy

    Science.gov (United States)

    Trabucchi, Stefano; Casella, Francesco; Maioli, Tommaso; Elsido, Cristina; Franzini, Davide; Ramond, Mathieu

    2017-06-01

    Concentrated Solar Power plants (CSP) coupled with thermal storage have the potential to guarantee both flexible and continuous energy production, thus being competitive with conventional fossil fuel and hydro power plants, in terms of dispatchability and provision of ancillary services. Hence, the plant equipment and control design have to be focused on flexible operation on one hand, and on plant safety concerning the molten salt freezing on the other hand. The PreFlexMS European project aims to introduce a molten salt Once-Through Steam Generator (OTSG) within a Rankine cycle based power unit, a technology that has greater flexibility potential if compared to steam drum boilers, currently used in CSP plants. The dynamic modelling and simulation from the early design stages is, thus, of paramount importance, to assess the plant dynamic behavior and controllability, and to predict the achievable closed-loop dynamic performance, potentially saving money and time during the detailed design, construction and commissioning phases. The present paper reports the main results of the analysis carried out during the first part of the project, regarding the system analysis and control design. In particular, two different control systems have been studied and tested with the plant dynamic model: a decentralized control strategy based on PI controllers and a Linear Model Predictive Control (LMPC).

  18. HTGR-GT closed-cycle gas turbine: a plant concept with inherent cogeneration (power plus heat production) capability

    International Nuclear Information System (INIS)

    McDonald, C.F.

    1980-04-01

    The high-grade sensible heat rejection characteristic of the high-temperature gas-cooled reactor-gas turbine (HTGR-GT) plant is ideally suited to cogeneration. Cogeneration in this nuclear closed-cycle plant could include (1) bottoming Rankine cycle, (2) hot water or process steam production, (3) desalination, and (4) urban and industrial district heating. This paper discusses the HTGR-GT plant thermodynamic cycles, design features, and potential applications for the cogeneration operation modes. This paper concludes that the HTGR-GT plant, which can potentially approach a 50% overall efficiency in a combined cycle mode, can significantly aid national energy goals, particularly resource conservation

  19. Effect of a diffuser on performance enhancement of a cylindrical methanol steam reformer by computational fluid dynamic analysis

    International Nuclear Information System (INIS)

    Perng, Shiang-Wuu; Horng, Rong-Fang; Wu, Horng-Wen

    2017-01-01

    Highlights: •We enhance performance of a cylindrical MSR to get higher net power of fuel cell. •We study diffuser angle and length and wall temperature on net power of fuel cell. •We study methanol conversion, hydrogen production, CO of a novel reformer. •Diffuser in catalyst bed upstream raises methanol conversion, hydrogen production. •The MSR raises hydrogen production up to 44.6% and net fuel cell power up to 24.6%. -- Abstract: Proton exchange membrane fuel cells (PEMFC) connected with a methanol steam reformer designed to enhance its performance is considered as a promising future power source. Enhancing the performance of a cylindrical methanol steam reformer due to diffuser effects was then investigated applying three-dimensional computational fluid dynamics by the SIMPLE-C algorithm and an Arrhenius form of reaction model. The effect of the angle and length of the diffuser, and wall temperature have been explored on heat and fluid flow, methanol conversion, hydrogen production, carbon monoxide reduction, as well as estimated net power of fuel cell with the same catalyst volume and entrance condition in a cylindrical methanol steam reformer. The results indicate that the diffuser obviously enhances methanol conversion and hydrogen production of a cylindrical methanol steam reformer. In comparison with a traditional reformer, the reformer with a diffuser of θ d = 6° and L d = 75 mm obtains the maximum enhancement of 22.96% in methanol conversion, 44.62% in hydrogen production, and 24.59% in estimated net power of fuel cell at wall temperature of 250 °C. In addition, the novel reformer with a diffuser of θ d = 9° and L d = 100 mm generates the maximum reduction of 44.17% in CO production at T W = 250 °C.

  20. STEAM by Design

    Science.gov (United States)

    Keane, Linda; Keane, Mark

    2016-01-01

    We live in a designed world. STEAM by Design presents a transdisciplinary approach to learning that challenges young minds with the task of making a better world. Learning today, like life, is dynamic, connected and engaging. STEAM (Science, Technology, Environment, Engineering, Art, and Math) teaching and learning integrates information in…

  1. On detonation dynamics in hydrogen-air-steam mixtures: Theory and application to Olkiluoto reactor building

    International Nuclear Information System (INIS)

    Silde, A.; Lindholm, I.

    2000-02-01

    This report consists of the literature study of detonation dynamics in hydrogen-air-steam mixtures, and the assessment of shock pressure loads in Olkiluoto 1 and 2 reactor building under detonation conditions using the computer program DETO developed during this work at VTT. The program uses a simple 1-D approach based on the strong explosion theory, and accounts for the effects of both the primary or incident shock and the first (oblique or normal) reflected shock from a wall structure. The code results are also assessed against a Balloon experiment performed at Germany, and the classical Chapman-Jouguet detonation theory. The whole work was carried out as a part of Nordic SOS-2.3 project, dealing with severe accident analysis. The initial conditions and gas distribution of the detonation calculations are based on previous severe accident analyses by MELCOR and FLUENT codes. According to DETO calculations, the maximum peak pressure in a structure of Olkiluoto reactor building room B60-80 after normal shock reflection was about 38.7 MPa if a total of 3.15 kg hydrogen was assumed to burned in a distance of 2.0 m from the wall structure. The corresponding pressure impulse was about 9.4 kPa-s. The results were sensitive to the distance used. Comparison of the results to classical C-J theory and the Balloon experiments suggested that DETO code represented a conservative estimation for the first pressure spike under the shock reflection from a wall in Olkiluoto reactor building. Complicated 3-D phenomena of shock wave reflections and focusing, nor the propagation of combustion front behind the shock wave under detonation conditions are not modeled in the DETO code. More detailed 3-D analyses with a specific detonation code are, therefore, recommended. In spite of the code simplifications, DETO was found to be a beneficial tool for simple first-order assessments of the structure pressure loads under the first reflection of detonation shock waves. The work on assessment

  2. Presentation summary: Gas Turbine - Modular Helium Reactor (GT-MHR)

    International Nuclear Information System (INIS)

    2001-01-01

    Numerous prototypes and demonstration plants have been constructed and operated beginning with the Dragon plant in the early 1960s. The MHTGR was the U.S. developed modular plant and underwent pre application review by NRC. The GT-MHR represents a further refinement on this concept with the steam cycle being replaced by a closed loop gas turbine (Brayton) cycle. Modular gas reactors and the GT-MHR represent a fundamental shift in reactor design and safety philosophy. The reactor system is contained in a 3 vessel, side-by-side arrangement. The reactor and a shutdown cooling system are in one vessel, and the gas turbine based power conversion system, including the generator, in a second parallel vessel. A more detailed look at the system shows the compact arrangement of gas turbine, compressors, recuperator, heat exchanges, and generator. Fueled blocks are stacked in three concentric rings with inert graphite blocks making up the inner and outer reflectors. Operating control rods are located outside the active core while startup control rods and channels for reserve shutdown pellets are located near the core center. Ceramic coated fuel is the key to the GT-MHR's safety and economics. A kernel of Uranium oxycarbide (or UO 2 ) is placed in a porous carbon buffer and then encapsulated in multiple layers of pyrolytic carbon and silicon carbide. These micro pressure vessels withstand internal pressures of up to 2,000 psi and temperatures of nearly 2,000 C providing extremely resilient containment of fission products under both normal operating and accident conditions. The fuel particles are blended in carbon pitch, forming fuel rods, and then loaded into holes within large graphite fuel elements. Fuel elements are stacked to form the core. Fuel particle testing in has repeatedly demonstrated the high temperature resilience of coated particle fuel to temperature approaching 2,000 C. As an conservative design goal, GT-MHR has been sized to keep maximum fuel temperatures

  3. Dynamic Simulation of the Water-steam System in Once-through Boilers - Sub-critical Power Boiler Case -

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seongil; Choi, Sangmin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2017-05-15

    The dynamics of a water-steam system in a once-through boiler was simulated based on the physics-based modeling approach, representing the system in response to large load change or scale disturbance simulations. The modeling considered the mass, energy conservation, and momentum equation in the water pipe and the focus was limited to the sub-critical pressure region. An evaporator tube modeling was validated against the reference data. A simplified boiler system consisting of economizer, evaporator, and superheater was constructed to match a 500 MW power boiler. The dynamic response of the system following a disturbance was discussed along with the quantitative response characteristics. The dynamic response of the boiler system was further evaluated by checking the case of an off-design point operation of the feedwater-to-fuel supply ratio. The results re-emphasized the significance of controlling the feedwater-to-fuel supply ratio and additional design requirements of the water-steam separator and spray attemperator.

  4. Dynamic Simulation of the Water-steam System in Once-through Boilers - Sub-critical Power Boiler Case -

    International Nuclear Information System (INIS)

    Kim, Seongil; Choi, Sangmin

    2017-01-01

    The dynamics of a water-steam system in a once-through boiler was simulated based on the physics-based modeling approach, representing the system in response to large load change or scale disturbance simulations. The modeling considered the mass, energy conservation, and momentum equation in the water pipe and the focus was limited to the sub-critical pressure region. An evaporator tube modeling was validated against the reference data. A simplified boiler system consisting of economizer, evaporator, and superheater was constructed to match a 500 MW power boiler. The dynamic response of the system following a disturbance was discussed along with the quantitative response characteristics. The dynamic response of the boiler system was further evaluated by checking the case of an off-design point operation of the feedwater-to-fuel supply ratio. The results re-emphasized the significance of controlling the feedwater-to-fuel supply ratio and additional design requirements of the water-steam separator and spray attemperator.

  5. Severe transient tests on operation steam generators: Analysis of the fluid structure dynamic thermal interaction

    International Nuclear Information System (INIS)

    Billon, F.; David, J.; Procaccia, H.

    1983-01-01

    The operating efficiency of steam generators (S.G.s) and their structural integrity depend on the design configurations of the feedwater spray within the S.G., and on the operating procedure. To check the merit of some design modifications, and to verify the fluid-structure interaction with a view to preserve the S.G.s integrity during severe operating transients, a special instrumentation that admits the determination of the instantaneous thermal hydraulic characteristics of the flow in the secondary water and the S.G. tube sheet, has been installed by EDF on one steam generator of Tricastin unit 1 power plant. In parallel, FRAMATOME has developped a computer code, TEMPTRON, that allows the calculations of the thermal loads and the consequent stresses in the most sollicited zones of the steam generator during transient operation of the plant. This code divides the S.G. into three parts: - the first concerns the S.G.s region above the downcomer, zone where the mixing between hot water and cold feedwater occurs, - the second is the downcomer itself which is divided into n segments, - the third concerns the tube sheet zone which is also divided into n segments. The most severe transient test performed is the auxiliary cold feedwater injection into the steam generator during a hot standby of the plant: two levels of flow rate have been realised: 55 and 110 m 3 /h of 42 0 C feedwater. The tests have shown that if the cold feedwater injection occurs when the steam generator water level is below feedwater ring, the lowest fluid temperature reached at tube sheet inlet is about 230 0 C. (orig.)

  6. Striking a Balance between Program Requirements and GT Principles: Writing a compromised GT proposal

    Directory of Open Access Journals (Sweden)

    Sherry L. Xie, Ph.D. Candidate

    2009-06-01

    Full Text Available Glaser’s term “compromised GT proposal” (2001, p.114 refers to the type of Grounded Theory (GT proposal that is written in order to conform to the requirements of a standardized qualitative research proposal. A GT proposal needs only to supply information on the area of interest, the data source and a statement of method to the effect that the researcher begin to collect, code and analyse the data and let the theory emerge. Thus, the proposal may only occupy “a page or two” (Glaser, 2001, p. 111. Whilst being consistent with the methodology, a GT proposal sometimes has to give way to the format specified by a PhD program or committee even though the format was not defined for a GT proposal and in some areas, conflicts with GT principles; for example, the format may require a literature review. This short paper reports on my experience of writing a compromised GT proposal as a first-time GT researcher. It describes how both Glaser’s advice on writing compromised GT research proposals and the characteristics of the substantive area of the proposed research were used to satisfy program requirements while still maintaining GT fundamentals.

  7. Turbo-machine deployment of HTR-10 GT

    International Nuclear Information System (INIS)

    Zhu Shutang; Wang Jie; Zhang Zhengming; Yu Suyuan

    2005-01-01

    As a testing project of gas turbine modular High Temperature Gas-cooled Reactor (HTGR), HTR-10GT has been studied and developed by Institute of Nuclear and New Energy Technology (INET) of Tsinghua University after the success of HTR-10 with steam turbine cycle. The main purposes of this project are to demonstrate the gas turbine modular HTGR, to optimize the deployment of Power Conversion Unit (PCU) and to verify the techniques of turbo-machine, operating modes and controlling measures. HTR-10GT is concentrated on the PCU design and the turbo-machine deployment. Possible turbo-machine deployments have been investigated and two of them are introduced in this paper. The preliminary design for the turbo-machine of HTR-10GT is single-shaft of vertical layout, arranged by the side of the reactor and the turbo-compressor rotary speed was selected to be 250 s -1 (15000 r/min) by considering the efficiency of turbo-compressor blade systems, the strength conditions and the mass and size characteristics of the turbo-compressor. The rotor system will be supported by electromagnetic bearings (EMBs) to curb the possible pollutions of the primary loop. Of all the components in this design, the high speed turbo-generator seems to be a world-wide technical nut. As an alternative design, a gearbox complex is used to reduce the rotary speed from the turbo-compressor 250 s -1 to 50 s -1 so that the ordinary generator can be used. (authors)

  8. ORTAP: a nuclear steam supply system simulation for the dynamic analysis of high temperature gas cooled reactor transients

    International Nuclear Information System (INIS)

    Cleveland, J.C.; Hedrick, R.A.; Ball, S.J.; Delene, J.G.

    1977-01-01

    ORTAP was developed to predict the dynamic behavior of the high temperature gas cooled reactor (HTGR) Nuclear Steam Supply System for normal operational transients and postulated accident conditions. It was developed for the Nuclear Regulatory Commission (NRC) as an independent means of obtaining conservative predictions of the transient response of HTGRs over a wide range of conditions. The approach has been to build sufficient detail into the component models so that the coupling between the primary and secondary systems can be accurately represented and so that transients which cover a wide range of conditions can be simulated. System components which are modeled in ORTAP include the reactor core, a typical reheater and steam generator module, a typical helium circulator and circulator turbine and the turbine generator plant. The major plant control systems are also modeled. Normal operational transients which can be analyzed with ORTAP include reactor start-up and shutdown, normal and rapid load changes. Upset transients which can be analyzed with ORTAP include reactor trip, turbine trip and sudden reduction in feedwater flow. ORTAP has also been used to predict plant response to emergency or faulted conditions such as primary system depressurization, loss of primary coolant flow and uncontrolled removal of control poison from the reactor core

  9. Dynamic performances of wet turbine and steam-separator-superheater and their mathematical simulation as objects of temperature control

    International Nuclear Information System (INIS)

    Golovach, E.A.

    1985-01-01

    A mathematical model of a turbine and steam-separator-superheater (SSS) as applied to solution of the tasks of steam temperature regulaton after SSS has been developed. SSS as objects of steam temperature control are considerably less inertial, than intermediate superheaters (IS) of power units in thermal power plants, since for typical SSS and IS considered the duration of transition process according to steam temperature after SSS is 5-10 times loweA than for IS

  10. Influence of the degree of simplification of the two-phase hydrodynamic model on the simulated behaviour dynamics of a steam generator

    International Nuclear Information System (INIS)

    Dupont, J.F.

    1979-03-01

    The principal simplifications of a mathematical model for the simulation of behaviour dynamics of a two-phase flow with heat exchange are examined, as it appears in a steam generator. The theoretical considerations and numerical solutions permit the evaluation of the validity limits and the influence of these simplifications on the results. (G.T.H.)

  11. Dynamic analysis of multi layer foundation of steam turbines in nuclear power plants

    International Nuclear Information System (INIS)

    Hosseni, D.

    1999-01-01

    In this work, the coupled Rotor-pedestal-foundation motion is modeled and formulated. Transfer matrix method is implemented in the modeling. The model is adequate for multi layer foundation systems of steam turbines in nuclear power plants. The rotor modeled used is distributed mass model. Bearings are modeled with eight stiffness and damping coefficients and pedestals by mass, stiffness and damping property. Foundation is modeled with distributed mass and stiffness properties in which properties in vertical and horizontal direction may be different. The model is examined using analytical results and good agreement is achieved. Results of the coupled modeling indicate less error in comparison with previous separate modeling and lumped-mass methods

  12. Application of dynamic probabilistic safety assessment approach for accident sequence precursor analysis: Case study for steam generator tube rupture

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Han Sul; Heo, Gyun Young [Kyung Hee University, Yongin (Korea, Republic of); Kim, Tae Wan [Incheon National University, Incheon (Korea, Republic of)

    2017-03-15

    The purpose of this research is to introduce the technical standard of accident sequence precursor (ASP) analysis, and to propose a case study using the dynamic-probabilistic safety assessment (D-PSA) approach. The D-PSA approach can aid in the determination of high-risk/low-frequency accident scenarios from all potential scenarios. It can also be used to investigate the dynamic interaction between the physical state and the actions of the operator in an accident situation for risk quantification. This approach lends significant potential for safety analysis. Furthermore, the D-PSA approach provides a more realistic risk assessment by minimizing assumptions used in the conventional PSA model so-called the static-PSA model, which are relatively static in comparison. We performed risk quantification of a steam generator tube rupture (SGTR) accident using the dynamic event tree (DET) methodology, which is the most widely used methodology in D-PSA. The risk quantification results of D-PSA and S-PSA are compared and evaluated. Suggestions and recommendations for using D-PSA are described in order to provide a technical perspective.

  13. Application of dynamic probabilistic safety assessment approach for accident sequence precursor analysis: Case study for steam generator tube rupture

    International Nuclear Information System (INIS)

    Lee, Han Sul; Heo, Gyun Young; Kim, Tae Wan

    2017-01-01

    The purpose of this research is to introduce the technical standard of accident sequence precursor (ASP) analysis, and to propose a case study using the dynamic-probabilistic safety assessment (D-PSA) approach. The D-PSA approach can aid in the determination of high-risk/low-frequency accident scenarios from all potential scenarios. It can also be used to investigate the dynamic interaction between the physical state and the actions of the operator in an accident situation for risk quantification. This approach lends significant potential for safety analysis. Furthermore, the D-PSA approach provides a more realistic risk assessment by minimizing assumptions used in the conventional PSA model so-called the static-PSA model, which are relatively static in comparison. We performed risk quantification of a steam generator tube rupture (SGTR) accident using the dynamic event tree (DET) methodology, which is the most widely used methodology in D-PSA. The risk quantification results of D-PSA and S-PSA are compared and evaluated. Suggestions and recommendations for using D-PSA are described in order to provide a technical perspective

  14. Modeling and simulation of a controlled steam generator in the context of dynamic reliability using a Stochastic Hybrid Automaton

    International Nuclear Information System (INIS)

    Babykina, Génia; Brînzei, Nicolae; Aubry, Jean-François; Deleuze, Gilles

    2016-01-01

    The paper proposes a modeling framework to support Monte Carlo simulations of the behavior of a complex industrial system. The aim is to analyze the system dependability in the presence of random events, described by any type of probability distributions. Continuous dynamic evolutions of physical parameters are taken into account by a system of differential equations. Dynamic reliability is chosen as theoretical framework. Based on finite state automata theory, the formal model is built by parallel composition of elementary sub-models using a bottom-up approach. Considerations of a stochastic nature lead to a model called the Stochastic Hybrid Automaton. The Scilab/Scicos open source environment is used for implementation. The case study is carried out on an example of a steam generator of a nuclear power plant. The behavior of the system is studied by exploring its trajectories. Possible system trajectories are analyzed both empirically, using the results of Monte Carlo simulations, and analytically, using the formal system model. The obtained results are show to be relevant. The Stochastic Hybrid Automaton appears to be a suitable tool to address the dynamic reliability problem and to model real systems of high complexity; the bottom-up design provides precision and coherency of the system model. - Highlights: • A part of a nuclear power plant is modeled in the context of dynamic reliability. • Stochastic Hybrid Automaton is used as an input model for Monte Carlo simulations. • The model is formally built using a bottom-up approach. • The behavior of the system is analyzed empirically and analytically. • A formally built SHA shows to be a suitable tool to approach dynamic reliability.

  15. Tests of Hadronic Probes of GT Strength

    CERN Multimedia

    2002-01-01

    There are many important problems where one wishes to know the distribution of Gamow-Teller (GT) strength in circumstances where it cannot be measured directly (for example, because of energy-release limitations). Then one must rely on hadronic probes to infer the GT strength. It is therefore essential to test these probes as extensively as possible. The isospin-analog transitions in $^{37}$Ca $\\beta^{+}$ -decay and $^{37}$Cl$(p, n)$ provide an excellent ground for such a test. Recent $^{37}$Cl$ (p, n) $ studies, while qualitatively in agreement with our previous ISOLDE work on $^{37}$Ca $\\beta^{+} $ -decay, show quantitative discrepancies that appear to grow as the excitation energy in the residual nuclei increases. Because of the bulk of the GT strengh appears at these high excitation energies, it is important to extend the $\\beta$-decay data to even higher excitation energies where, because of rapidly diminishing phase-space, strong GT transitions correspond to very weak $\\beta$ -branches. We propose to do...

  16. GT-MHR design, performance, and safety

    International Nuclear Information System (INIS)

    Neylan, A.J.; Shenoy, A.; Silady, F.A.; Dunn, T.D.

    1994-11-01

    The Gas Turbine-Modular Helium Reactor (GT-MHR) is the result of coupling the evolution of a low power density passively safe modular reactor with key technology developments in the U.S. during the last decade: large industrial gas turbines; large active magnetic bearings; and compact, highly effective plate-fin heat exchangers. This is accomplished through the unique use of the Brayton cycle to produce electricity with the helium as primary coolant from the reactor directly driving the gas turbine electrical generator. This cycle can achieve a high net efficiency in the range of 45% to 48%. In the design of the GT-MHR the desirable inherent characteristics of the inert helium coolant, graphite core, and the coated fuel particles are supplemented with specific design features such as passive heat removal to achieve the safety objective of not disturbing the normal day-to-day activities of the public even for beyond design basis rare accidents. Each GT-MHR plant consists of four modules. The GT-MHR module components are contained within steel pressure vessels: a reactor vessel, a power conversion vessel, and a connecting cross vessel. All vessels are sited underground in a concrete silo, which serves as an independent vented low pressure containment structure. By capitalizing on industrial and aerospace gas turbine development, highly effective heat exchanger designs, and inherent gas cooled reactor temperature characteristics, the passively safe GT-MHR provides a sound technical, monetary, and environmental basis for new nuclear power generating capacity. This paper provides an update on the status of the design, which has been under development on the US-DOE program since February 1993. An assessment of plant performance and safety is also included

  17. HTR-10GT AMBs displacement sensor design

    International Nuclear Information System (INIS)

    Shi Zhengang; Zha Meisheng; Zhao Lei; Sun Zhuo

    2005-01-01

    The 10 MW high temperature gas-cooled test module reactor (HTR-10GT) with the core made of spherical fuel elements was designed and constructed by the Institute of Nuclear and New Energy Technology of Tsinghua University in China. In the HTR-10GT, turbo-compressor and generator rotors are connected by a flexible coupling. The rotors, restricted by actual instruments and working environment, must be supported without any contact and lubrication. Active magnetic bearing (AMB), known as its advantages over the conventional bearings., such as contact-free, no-lubricating and active damping vibration, is the best way to suspend and stabilize the position of rotors of HTR-10GT. Each rotor is suspended by two radial and one axial AMBs. The radial AMB's radial gap is 0.15 mm considering the gap of 0.4 mm between the compressor stator and blades in order to protect the compressor. The control system controls the rotor position to meet the required gaps between rotor and stator through windings current. All the position information concerning radial and axial AMB is generated by sensors for measuring the displacement of the levitated body. Some typical sensors, i.e. eddy current displacement sensor, capacitive displacement sensor, can provide position information, but, quite often, unsatisfactory anti-jamming, which is a key issue for AMB systems near generator and other electric devices in HTR-10GT. Therefore, a kind of new type sensor is designed to measure the radial and axial displacements and the vibration of the rotors. This paper focuses on the design characteristics of the HTR-10GT AMBs displacement sensors and introduction of the related experiments to demonstrate its performance. (authors)

  18. Steam drums

    International Nuclear Information System (INIS)

    Crowder, R.

    1978-01-01

    Steam drums are described that are suitable for use in steam generating heavy water reactor power stations. They receive a steam/water mixture via riser headers from the reactor core and provide by means of separators and driers steam with typically 0.5% moisture content for driving turbines. The drums are constructed as prestressed concrete pressure vessels in which the failure of one or a few of the prestressing elements does not significantly affect the overall strength of the structure. The concrete also acts as a radiation shield. (U.K.)

  19. Calculation of relative tube/tube support plate displacements in steam generators under accident condition loads using non-linear dynamic analysis methodologies

    International Nuclear Information System (INIS)

    Smith, R.E.; Waisman, R.; Hu, M.H.; Frick, T.M.

    1995-01-01

    A non-linear analysis has been performed to determine relative motions between tubes and tube support plates (TSP) during a steam line break (SLB) event for steam generators. The SLB event results in blowdown of steam and water out of the steam generator. The fluid blowdown generates pressure drops across the TSPS, resulting in out-of-plane motion. The SLB induced pressure loads are calculated with a computer program that uses a drift-flux modeling of the two-phase flow. In order to determine the relative tube/TSP motions, a nonlinear dynamic time-history analysis is performed using a structural model that considers all of the significant component members relative to the tube support system. The dynamic response of the structure to the pressure loads is calculated using a special purpose computer program. This program links the various substructures at common degrees of freedom into a combined mass and stiffness matrix. The program accounts for structural non-linearities, including potential tube and TSP interaction at any given tube position. The program also accounts for structural damping as part of the dynamic response. Incorporating all of the above effects, the equations of motion are solved to give TSP displacements at the reduced set of DOF. Using the displacement results from the dynamic analysis, plate stresses are then calculated using the detailed component models. Displacements form the dynamic analysis are imposed as boundary conditions at the DOF locations, and the finite element program then solves for the overall distorted geometry. Calculations are also performed to assure that assumptions regarding elastic response of the various structural members and support points are valid

  20. Development of a simulation platform for dynamic simulation and control studies of AP1000 nuclear steam supply system

    International Nuclear Information System (INIS)

    Wan, Jiashuang; Song, Hongbing; Yan, Shoujun; Sun, Jian; Zhao, Fuyu

    2015-01-01

    Highlights: • A fast-running simulation platform named NCAP was developed on a personal computer using MATLAB/Simulink. • Three types of typical operations, namely 10% step load change, 5%/min ramp load change and load follow were simulated. • NCAP predictions were compared with those obtained by CENTS for the load regulation transients. - Abstract: This paper presents the development, application and performance assessment of a fast-running NCAP (NSSS Control & Analysis Platform) in MATLAB/Simulink environment. First, a nodal core model, a lumped parameter dynamic steam generator model with moving boundary, a non-equilibrium two-regions-three-volumes pressurizer model, and the relevant pipe and plenum models were proposed based on the fundamental conservation of mass, energy and momentum. Then, these first order nonlinear models and the NSSS control systems were implemented in the Simulink by the predefined library blocks. Based on the developed NCAP, three types of typical operational transients, namely the 10% step load change, the 5%/min ramp load change and the daily load follow were simulated to study the dynamic behavior and control characteristics of the AP1000 NSSS. It has been demonstrated that the dynamic responses of the selected key parameters agree well with the general physical rules. In addition, the comparison of load regulation simulation results obtained by NCAP and CENTS shows a good agreement in terms of the changing trends. With the adoption of modular programming techniques, the NCAP facilitates easy modification and runs quickly, which easily allows the control system designer to test and compare various ideas efficiently

  1. Steam 80 steam generator instrumentation

    International Nuclear Information System (INIS)

    Carson, W.H.; Harris, H.H.

    1980-01-01

    This paper describes two special instrumentation packages in an integral economizer (preheater) steam generator of one of the first System 80 plants scheduled to go into commercial operation. The purpose of the instrumentation is to obtain accurate operating information from regions of the secondary side of the steam generator inaccessible to normal plant instrumentation. In addition to verification of the System 80 steam generator design predictions, the data obtained will assist in verification of steam generator thermal/hydraulic computer codes developed for generic use in the industry

  2. Selling steam

    International Nuclear Information System (INIS)

    Zimmer, M.J.; Goodwin, L.M.

    1991-01-01

    This article addresses the importance of steam sales contract is in financing cogeneration facilities. The topics of the article include the Public Utility Regulatory Policies Act provisions and how they affect the marketing of steam from qualifying facilities, the independent power producers market shift, and qualifying facility's benefits

  3. Steam generator

    International Nuclear Information System (INIS)

    Fenet, J.-C.

    1980-01-01

    Steam generator particularly intended for use in the coolant system of a pressurized water reactor for vaporizing a secondary liquid, generally water, by the primary cooling liquid of the reactor and comprising special arrangements for drying the steam before it leaves the generator [fr

  4. Steam condenser

    International Nuclear Information System (INIS)

    Masuda, Fujio

    1980-01-01

    Purpose: To enable safe steam condensation by providing steam condensation blades at the end of a pipe. Constitution: When high temperature high pressure steam flows into a vent pipe having an opening under water in a pool or an exhaust pipe or the like for a main steam eacape safety valve, non-condensable gas filled beforehand in the steam exhaust pipe is compressed, and discharged into the water in the pool. The non-condensable gas thus discharged from the steam exhaust pipe is introduced into the interior of the hollow steam condensing blades, is then suitably expanded, and thereafter exhausted from a number of exhaust holes into the water in the pool. In this manner, the non-condensable gas thus discharged is not directly introduced into the water in the pool, but is suitable expanded in the space of the steam condensing blades to suppress extreme over-compression and over-expansion of the gas so as to prevent unstable pressure vibration. (Yoshihara, H.)

  5. Two-phase flow dynamics in a model steam generator under vertical acceleration oscillation field

    International Nuclear Information System (INIS)

    Ishida, T.; Teshima, N.; Sakurai, S.

    1992-01-01

    The influence of periodically varying acceleration on hydrodynamic response has been studied experimentally using an experimental rig which models a marine reactor subject to vertical motion. The effect on the primary loop is small, but the effect on the secondary loop is large. The variables of the secondary loop, such as circulation flow rate and water level, oscillate with acceleration. The variation of gains in frequency response is analysed. The variations of flow in the secondary loop and in the downcome water level, increase in proportion to the acceleration. The effect of the flow resistance in the secondary loop on the two-phase flow dynamics is clarified. (7 figures) (Author)

  6. Design of SMART steam generator cassette

    International Nuclear Information System (INIS)

    Kim, Y. W.; Kim, J. I.; Jang, M. H.

    2001-01-01

    Basic design development for the steam generator to be installed in the integral reactor SMART has been performed. Optimization of the steam generator shape, determination of the basic dimension and confirmation of the structural strength have been carried out. Individual steam generator cassette can be replaced in the optimized design concept of steam generator. Shape design of the steam generator cassette has been done on the computer based on 3-D CAE strategy. The structural integrity of the developed steam generator was investigated by performing the dynamic analysis for the steam generator cassette, flow induced vibration analysis for the tube bundle, and the thermo-mechanical analysis for the module header and tube. As for the manufacturing of steam generator, the numerical and the experimental simulation have been carried to control the amount of spring back and to eliminate residual stress. SMART steam generator cassette was developed by a sequential research of the aforementioned activities

  7. How can the heat transfer correlations for finned-tubes influence the numerical simulation of the dynamic behavior of a heat recovery steam generator?

    International Nuclear Information System (INIS)

    Walter, H.; Hofmann, R.

    2011-01-01

    This paper presents the results of a theoretical investigation on the influence of different heat transfer correlations for finned-tubes to the dynamic behavior of a heat recovery steam generator (HRSG). The investigation was done for a vertical type natural circulation HRSG with 3 pressure stages under hot start-up and shutdown conditions. For the calculation of the flue gas-side heat transfer coefficient the well known correlations for segmented finned-tubes according to Schmidt, VDI and ESCOA TM (traditional and revised) as well as a new correlation, which was developed at the Institute for Energy Systems and Thermodynamics, are used. The simulation results show a good agreement in the overall behavior of the boiler between the different correlations. But there are still some important differences found in the detail analysis of the boiler behavior. - Research highlights: → Numerical simulation is performed to explore the influence of different heat transfer correlations for finned-tubes to the dynamic behavior of a heat recovery steam generator. → Differences in the steam generator behavior are found. → In the worst case the boiler can lead to unfavorable operation conditions, e.g. reverse flow.

  8. Study of water dynamics in the soaking, steaming, and solid-state fermentation of glutinous rice by LF-NMR: a novel monitoring approach.

    Science.gov (United States)

    Li, Teng; Tu, Chuanhai; Rui, Xin; Gao, Yangwen; Li, Wei; Wang, Kun; Xiao, Yu; Dong, Mingsheng

    2015-04-01

    Solid-state fermentation (SSF) of starchy grain is a traditional technique for food and alcoholic beverage production in East Asia. In the present study, low-field nuclear magnetic resonance (LF-NMR) was introduced for the elucidation of water dynamics and microstructure alternations during the soaking, steaming, and SSF of glutinous rice as a rapid real-time monitoring method. Three different proton fractions with different mobilities were identified based on the degree of interaction between biopolymers and water. Soaking and steaming significantly changed the proton distribution of the sample. The different phases of SSF were reflected by the T2 parameters. In addition, the variations in the T2 parameters were explained by the microstructure changes of rice induced by SSF. The fermentation time and T2 parameters were sigmoidally correlated. Thus, LF-NMR may be an effective real-time monitoring method for SSF in starch systems.

  9. Fluid dynamic simulation of the non homogeneous steam-air mixture motion in the dome of MARS safety core cooling system

    International Nuclear Information System (INIS)

    Said, S.A.; Caira, M.; Gramiccia, L.; Naviglio, A.

    1992-01-01

    One of the main features of the MARS, an inherently safe nuclear reactor of the new generation, is the innovative decay heat removal system. This has a high inherent reliability thanks to the complete absence of active components. The core decay heat is removed by the vaporization of the water in an emergency reservoir; then the steam collected in the dome over the pool condenses in the air condenser and returns back to the reservoir creating a heat sink of nearly infinite capacity. The transient fluid dynamic numerical simulation of the steam-air mixture flow in the dome is presented. This allows an assessment to be made of the time required for the uncondensable gases to be evacuated. After that time the condenser works at its rated capacity. (4 figures) (Author)

  10. Selection of JAERI'S HTGR-GT concept

    International Nuclear Information System (INIS)

    Muto, Y.; Ishiyama, S.; Shiozawa, S.

    2001-01-01

    In JAERI, a feasibility study of HTGR-GT has been conducted as an assigned work from STA in Japan since January 1996. So far, the conceptual or preliminary designs of 600, 400 and 300 MW(t) power plants have been completed. The block type core and pebble-bed core have been selected in 600 MW(t) and 400/300 MW(t), respectively. The gas-turbine system adopts a horizontal single shaft rotor and then the power conversion vessel is separated into a turbine vessel and a heat exchanger vessel. In this paper, the issues related to the selection of these concepts are technically discussed. (author)

  11. Control-relevant modeling and simulation of a SOFC-GT hybrid system

    Directory of Open Access Journals (Sweden)

    Rambabu Kandepu

    2006-07-01

    Full Text Available In this paper, control-relevant models of the most important components in a SOFC-GT hybrid system are described. Dynamic simulations are performed on the overall hybrid system. The model is used to develop a simple control structure, but the simulations show that more elaborate control is needed.

  12. Control-relevant modeling and simulation of a SOFC-GT hybrid system

    OpenAIRE

    Rambabu Kandepu; Lars Imsland; Christoph Stiller; Bjarne A. Foss; Vinay Kariwala

    2006-01-01

    In this paper, control-relevant models of the most important components in a SOFC-GT hybrid system are described. Dynamic simulations are performed on the overall hybrid system. The model is used to develop a simple control structure, but the simulations show that more elaborate control is needed.

  13. Computational Fluid Dynamics Modeling of Steam Condensation on Nuclear Containment Wall Surfaces Based on Semiempirical Generalized Correlations

    Directory of Open Access Journals (Sweden)

    Pavan K. Sharma

    2012-01-01

    Full Text Available In water-cooled nuclear power reactors, significant quantities of steam and hydrogen could be produced within the primary containment following the postulated design basis accidents (DBA or beyond design basis accidents (BDBA. For accurate calculation of the temperature/pressure rise and hydrogen transport calculation in nuclear reactor containment due to such scenarios, wall condensation heat transfer coefficient (HTC is used. In the present work, the adaptation of a commercial CFD code with the implementation of models for steam condensation on wall surfaces in presence of noncondensable gases is explained. Steam condensation has been modeled using the empirical average HTC, which was originally developed to be used for “lumped-parameter” (volume-averaged modeling of steam condensation in the presence of noncondensable gases. The present paper suggests a generalized HTC based on curve fitting of most of the reported semiempirical condensation models, which are valid for specific wall conditions. The present methodology has been validated against limited reported experimental data from the COPAIN experimental facility. This is the first step towards the CFD-based generalized analysis procedure for condensation modeling applicable for containment wall surfaces that is being evolved further for specific wall surfaces within the multicompartment containment atmosphere.

  14. Steam generators

    International Nuclear Information System (INIS)

    Hayden, R.L.J.

    1979-01-01

    Steam generators for nuclear reactors are designed so that deposition of solids on the surface of the inlet side of the tubesheet or the inlet header with the consequent danger of corrosion and eventual tube failure is obviated or substantially reduced. (U.K.)

  15. Steam turbine cycle

    International Nuclear Information System (INIS)

    Okuzumi, Naoaki.

    1994-01-01

    In a steam turbine cycle, steams exhausted from the turbine are extracted, and they are connected to a steam sucking pipe of a steam injector, and a discharge pipe of the steam injector is connected to an inlet of a water turbine. High pressure discharge water is obtained from low pressure steams by utilizing a pressurizing performance of the steam injector and the water turbine is rotated by the high pressure water to generate electric power. This recover and reutilize discharged heat of the steam turbine effectively, thereby enabling to improve heat efficiency of the steam turbine cycle. (T.M.)

  16. Analysis of performance for centrifugal steam compressor

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Seung Hwan; Ryu, Chang Kook; Ko, Han Seo [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-12-15

    In this study, mean streamline and Computational fluid dynamics (CFD) analyses were performed to investigate the performance of a small centrifugal steam compressor using a latent heat recovery technology. The results from both analysis methods showed good agreement. The compression ratio and efficiency of steam were found to be related with those of air by comparing the compression performances of both gases. Thus, the compression performance of steam could be predicted by the compression performance of air using the developed dimensionless parameters.

  17. Analysis of performance for centrifugal steam compressor

    International Nuclear Information System (INIS)

    Kang, Seung Hwan; Ryu, Chang Kook; Ko, Han Seo

    2016-01-01

    In this study, mean streamline and Computational fluid dynamics (CFD) analyses were performed to investigate the performance of a small centrifugal steam compressor using a latent heat recovery technology. The results from both analysis methods showed good agreement. The compression ratio and efficiency of steam were found to be related with those of air by comparing the compression performances of both gases. Thus, the compression performance of steam could be predicted by the compression performance of air using the developed dimensionless parameters

  18. The gas turbine-modular helium reactor (GT-MHR), high efficiency, cost competitive, nuclear energy for the next century

    International Nuclear Information System (INIS)

    Zgliczynski, J.B.; Silady, F.A.; Neylan, A.J.

    1994-04-01

    The Gas Turbine-Modular Helium Reactor (GT-MHR) is the result of coupling the evolution of a small passively safe reactor with key technology developments in the US during the last decade: large industrial gas turbines, large active magnetic bearings, and compact, highly effective plate-fin heat exchangers. The GT-MHR is the only reactor concept which provides a step increase in economic performance combined with increased safety. This is accomplished through its unique utilization of the Brayton cycle to produce electricity directly with the high temperature helium primary coolant from the reactor directly driving the gas turbine electrical generator. This cannot be accomplished with another reactor concept. It retains the high levels of passive safety and the standardized modular design of the steam cycle MHTGR, while showing promise for a significant reduction in power generating costs by increasing plant net efficiency to a remarkable 47%

  19. NUMEL: a computer aided design suite for the assessment of the steady state, static/dynamic stability and transient responses of nuclear steam generators

    International Nuclear Information System (INIS)

    Rowe, D.; Lightfoot, P.

    1988-02-01

    NUMEL is a computer aided design suite for the assessment of the steady state, static/dynamic stability and transient responses of nuclear steam generators. The equations solved are those of a monotube coflow or counterflow heat exchanger. The advantages of NUMEL are its fast execution speed, robustness, extensive validation and flexibility coupled with ease of use. The code can simultaneously model up to four separate sections (e.g. reheater, HP boiler). This document is a user manual and describes in detail the running of the NUMEL suite. In addition, a discussion is presented of the necessary approximations involved in representing a serpentine or helical AGR boiler as a monotube counterflow heat exchanger. To date, NUMEL has been applied to the modelling of AGR, Fast Reactor and once through Magnox and conventional boilers. Other versions of the code are available for specialist applications, e.g. Magnox and conventional recirculation boilers. (author)

  20. A comparison of the Actigraph GT1M and GT3X accelerometers under standardized and free-living conditions

    International Nuclear Information System (INIS)

    Kaminsky, Leonard A; Ozemek, Cemal

    2012-01-01

    Prior to 2008, data collection from Actigraph accelerometers was only possible in the uniaxial mode. In 2009, Actigraph released the GT3X, which allows triaxial data collection. The purpose of this study was to determine if data collected by the GT3X in the uniaxial mode are comparable to its predecessor, the GT1M, under both standardized and free-living conditions. Thirty-four subjects (17 women and 17 men) provided complete data for this study. Subjects wore the accelerometers (one GT1M and one GT3X) on their waistband in line with the right and left anterior axillary lines. Each subject walked on a treadmill at speeds of 2.4, 3.2, 4.0, 4.8, 5.6 and 6.4 km h −1 for 5 min each, and then continued to wear both accelerometers for all waking hours for three consecutive days. Mean steady-state activity counts min –1 for both accelerometers were not statistically different for the standardized treadmill walking speeds and for mean minutes/day and activity counts/day for intensity classifications under the free-living condition. Based on comparisons made from both standardized walking speeds and free-living conditions, it is reasonable to compare data derived from either the GT1M or GT3X when collected in the uniaxial mode. (paper)

  1. Actual characteristics study on HTR-10GT coupling with direct gas turbine cycle

    International Nuclear Information System (INIS)

    Peng Xuechuang; Zhu Shutang; Wang Jie

    2005-01-01

    Compared with a plant of steam turbine cycle, a HTGR plant with direct gas turbine cycle has a higher thermal efficiency. A lot of investigations on the characteristics of HTR-10GT, which is the reactor studying project of Tsinghua University, have been carried out, however, all of them are based on the theoretical Brayton Cycle which neglects many actual conditions, such as leakage, pressure loss and so on. For engineering practices, leakage is an unavoidable problem. The difference of the location and capacity of leakage will directly influence the working medium's thermoparameters and lead to fall of the cycle efficiency. The present study is focused on the performance of an actual Brayton cycle with practical conditions of leakage. The present study which based on building the physical and mathematical model of the leakage, aims to study the actual characteristics of the direct gas turbine circle. (authors)

  2. Simulation of thermal fluid dynamics in parabolic trough receiver tubes with direct steam generation using the computer code ATHLET

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Alexander; Merk, Bruno [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany); Hirsch, Tobias; Pitz-Paal, Robert [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany). Inst. fuer Solarforschung

    2014-06-15

    In the present feasibility study the system code ATHLET, which originates from nuclear engineering, is applied to a parabolic trough test facility. A model of the DISS (DIrect Solar Steam) test facility at Plataforma Solar de Almeria in Spain is assembled and the results of the simulations are compared to measured data and the simulation results of the Modelica library 'DissDyn'. A profound comparison between ATHLET Mod 3.0 Cycle A and the 'DissDyn' library reveals the capabilities of these codes. The calculated mass and energy balance in the ATHLET simulations are in good agreement with the results of the measurements and confirm the applicability for thermodynamic simulations of DSG processes in principle. Supplementary, the capabilities of the 6-equation model with transient momentum balances in ATHLET are used to study the slip between liquid and gas phases and to investigate pressure wave oscillations after a sudden valve closure. (orig.)

  3. Steaming ahead

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    An example of the development of geothermal power in Indonesia is described. Wells are being drilled into the Salak volcano on Java, about 60km south of Jakarta. These let out high pressure hot water trapped 1 to 3km below the surface which can be flashed into steam for driving turbines. The hot water field has already produced 110MW of power since 1994 and is currently being expanded to 330MW. Some details of the drilling and civil engineering are given. Since Indonesia sits on the edge of giant tectonic boundary known as the ''Pacific ring of fire'', the potential for further development is enormous. Ultimately volcanic activity could release an estimated 27,000MW capacity. More realistically, 2,000MW of crustal power by 2020 is spoken of. (UK)

  4. Thermo Dynamics and Economics Evaluations: Substitution of the Extraction Steam with the Wasted Heat of Flue Gas

    Science.gov (United States)

    Hao, Lifen; Qiu, Lixia; Li, Jinping; Li, Dongxiong

    2018-01-01

    A new heat supplying system is proposed that utilizes the exhausted gas of the boiler to substitute the extraction steam from the turbine as the driving force for the adsorption heat pump regarding the recovery of the condensation heat of power plant. However, our system is not subject to the low efficiency of wasted heat utilization due to the low temperature of flue gas, which hence possesses higher performance in COP factors in the utilization of heat than that of the conventional techniques of using flues gas, so the amount of extracted gas from turbine can be reduced and the power generate rate be enhanced. Subsequently, detailed evaluation of the performance of this system in the point of views of thermodynamics and economics are presented in this work. For the instance of a 330 MW heat supply unit, 5 sample cities are chosen to demonstrate and confirm our economic analysis. It is revealed that when the heating coefficient of the heat pump is 1.8, the investment payback periods for these 5 cities are within the range of 2.4 to 4.8 years, which are far below the service year of the heat pump, demonstrating remarkable economic benefits for our system.

  5. Steam Digest 2002

    Energy Technology Data Exchange (ETDEWEB)

    2003-11-01

    Steam Digest 2002 is a collection of articles published in the last year on steam system efficiency. DOE directly or indirectly facilitated the publication of the articles through it's BestPractices Steam effort. Steam Digest 2002 provides a variety of operational, design, marketing, and program and program assessment observations. Plant managers, engineers, and other plant operations personnel can refer to the information to improve industrial steam system management, efficiency, and performance.

  6. Thermal cycle efficiency of the indirect combined HTGR-GT power generation system

    Energy Technology Data Exchange (ETDEWEB)

    Muto, Yasushi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-02-01

    High thermal efficiency of 50% could be expected in a power generation system coupling a high temperature gas-cooled reactor(HTGR) with a closed cycle gas turbine(GT). There are three candidate systems such as a direct cycle(DC), an indirect cycle(ICD) and an indirect combined cycle(IDCC). The IDCC could solve many problems in both the DC and the IDC and consists of a primary circuit and a secondary circuit where a topping cycle is a Brayton cycle and a bottoming cycle is a steam cycle. In this report, the thermal cycle efficiency of the IDCC is examined regarding configurations of components and steam pressure. It has been shown that there are two types of configurations, that is, a perfect cascade type and a semi-cascade one and the latter can be further classified into Case A, Case B and Case C. The conditions achieving the maximum thermal cycle efficiency were revealed for these cases. In addition, the optimum system configurations were proposed considering the thermal cycle efficiency, safety and plant arrangement. (author).

  7. Vibration Analysis for Steam Dryer of APR1400 Steam Generator

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sung-heum; Ko, Doyoung [KHNP CRI, Daejeon (Korea, Republic of); Cho, Minki [Doosan Heavy Industry, Changwon (Korea, Republic of)

    2016-10-15

    This paper is related to comprehensive vibration assessment program for APR1400 steam generator internals. According to U.S. Nuclear Regulatory Commission, Regulatory Guide 1.20 (Rev.3, March 2007), we conducted vibration analysis for a steam dryer as the second steam separator of steam generator internals. The vibration analysis was performed at the 100 % power operating condition as the normal operation condition. The random hydraulic loads were calculated by the computational fluid dynamics and the structural responses were predicted by power spectral density analysis for the probabilistic method. In order to meet the recently revised U.S. NRC RG 1.20 Rev.3, the CVAP against the potential adverse flow effects in APR1400 SG internals should be performed. This study conducted the vibration response analysis for the SG steam dryer as the second moisture separator at the 100% power condition, and evaluated the structural integrity. The predicted alternating stress intensities were evaluated to have more than 17.78 times fatigue margin compared to the endurance limit.

  8. International project GT-MHR - New generation of nuclear reactors

    International Nuclear Information System (INIS)

    Vasyaev, A.; Kodochigov, N.; Kuzavkov, N.; Kuznetsov, L.

    2001-01-01

    Gas turbine-modular helium reactor (GT-MHR) is the reactor of new generation, which satisfies the requirements of the progressing large-scale nuclear power engineering. The activities in GT-MHR Project started in 1995. In 1997 the Conceptual Design was developed under four-side Agreement (MINATOM, General Atomics, FRAMATOME, Fuji Electric); it has passed through the internal and international reviews, has been approved and recommended for further development as one of new trends in creation of new generation plants. Starting from 1999, the activities in the development of the Preliminary Design of the plant were deployed under the Agreement between the Government of the United States of America and the Government of the Russian Federation on Scientific and Technical Cooperation in the Management of Plutonium That Has Been Withdrawn From Nuclear Military Programs dated July 24, 1998. The activities are established under the Contract between MINATOM and OKBM Russia, and under the General Agreement between Department of Energy (DOE), USA and OKBM. The GT-MHR Project is included into 'Development Strategy of Russian Nuclear Power in the first Half of the XXI-st Century' providing for 'the participation in an international project on the development and construction of GT-MHR nuclear power plant till year 2010 and 'operation of GT-MHR prototype unit and creation of fuel fabrication facility (within framework of International Project) till year 2030'. (author)

  9. Steam turbine installations

    International Nuclear Information System (INIS)

    Bainbridge, A.

    1976-01-01

    The object of the arrangement described is to enable raising steam for driving steam turbines in a way suited to operating with liquid metals, such as Na, as heat transfer medium. A preheated water feed, in heat transfer relationship with the liquid metals, is passed through evaporator and superheater stages, and the superheated steam is supplied to the highest pressure stage of the steam turbine arrangement. Steam extracted intermediate the evaporator and superheater stages is employed to provide reheat for the lower pressure stage of the steam turbine. Only a major portion of the preheated water feed may be evaporated and this portion separated and supplied to the superheater stage. The feature of 'steam to steam' reheat avoids a second liquid metal heat transfer and hence represents a simplification. It also reduces the hazard associated with possible steam-liquid metal contact. (U.K.)

  10. Summarized report of geothermal well Gross Buchholz Gt1; Kurzprofil der Geothermiebohrung Gross Buchholz Gt1

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Frauke; Hesshaus, Annalena; Jatho, Reiner; Luppold, Friedrich-Wilhelm; Pletsch, Thomas; Tischner, Torsten [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany); Hunze, Sabine; Orilski, Judith; Wonik, Thomas [Leibniz-Institut fuer Angewandte Geophysik (LIAG), Hannover (Germany); Roehling, Heinz-Gerd [Landesamt fuer Bergbau, Energie und Geologie (LBEG), Hannover (Germany)

    2012-01-15

    The well Gross Buchholz Gt1 is a deep geothermal well intended to demonstrate the feasibility of deep geothermal energy mining from tight sedimentary rocks. It is the core part of the GeneSys (Generated Geothermal Energy Systems) project, aiming at developing single well concepts for direct use of geothermal energy. During the course of the project, three different single well concepts have been developed and tested at the research well Horstberg Z1 which is geologically comparable to the Gross Buchholzwell. The latter is intended to supply the heating energy for the premises of Geozentrum Hannover, an office and lab complex of some 35.000 m{sup 2} housing about 1000 employees. The geothermal target are the sandstones of the Lower Triassic Middle Buntsandstein Formation, which have a temperature of about 165 C at 3700 depth. The well has reached a final depth of 3901 m below ground level, penetrating a nearly complete succession from the Lower Cretaceous (Albian) to the Lower Triassic (Lower Buntsandstein), while Tertiary and Upper Cretaceous sediments are missing. This article summarizes technical and geographic data, stratigraphic classification, geophysical logging, cores, and sidewall cores of the well. (orig.)

  11. Signal analysis of steam line acoustics

    International Nuclear Information System (INIS)

    Martin, C. Samuel

    2003-01-01

    The vibration of nuclear steam piping is usually associated with pressure fluctuations emanating from flow disturbances such as steam generator nozzles, bends, or other pipe fittings. Flow separation at pipe tees and within steam chest manifolds or headers generate pressure fluctuations that propagate both upstream to steam generators as well as downstream to the steam turbine. Steady-state acoustic oscillations at various frequencies occur within the piping, possibly exciting structural vibrations. This paper focuses on the assessment of the origin of the disturbances using signal analyses of two dynamic pressure recordings from pressure transducers located along straight runs in the steam piping. The technique involves performing the cross spectrum to two dynamic pressure signals in piping between (1) the steam generator and steam chest header, and (2) between the header and steam turbine outlet. If, at a specified frequency, no causality occurs between the two signals then the cross spectra magnitude will be negligible. Of interest here is the value of the phase between the two signals for frequencies for which the magnitude of the cross spectrum is not negligible. It is shown in the paper that the direction of the dominant waves at all frequencies can be related to the phase angle from the cross spectrum. It has to be realized that pressure waves emanating from one source such as a steam generator will propagate along uniform steam pipes with little transformation or attenuation, but will be reflected at fittings and at inlets and outlets. Hence, the eventual steady-state time record at a given location in the piping is a result of not only the disturbance, but also reflections of earlier pulsations. Cross-spectral analyses has been employed to determine the direction of the dominant acoustic waves in the piping for various frequencies for which there are signals. To prove the technique, synthetic spectra are generated comprised of harmonic waves moving both

  12. HTGR-GT and electrical load integrated control

    International Nuclear Information System (INIS)

    Chan, T.; Openshaw, F.; Pfremmer, D.

    1980-05-01

    A discussion of the control and operation of the HTGR-GT power plant is presented in terms of its closely coupled electrical load and core cooling functions. The system and its controls are briefly described and comparisons are made with more conventional plants. The results of analyses of selected transients are presented to illustrate the operation and control of the HTGR-GT. The events presented were specifically chosen to show the controllability of the plant and to highlight some of the unique characteristics inherent in this multiloop closed-cycle plant

  13. Life cycle assessment of an SOFC/GT process

    Energy Technology Data Exchange (ETDEWEB)

    Olausson, Pernilla

    1999-06-01

    For the last few years much effort has been put into the research on different kinds of fuel cells, since these are considered to be both an efficient and environment friendly way to convert energy. The fuel cell studied here is the solid oxide fuel cell (SOFC) that works at a high temperature (800-1000 C) and today achieves a stand-alone electric efficiency of approximately 50%. When integrating the SOFC in a gas turbine process (SOFC/GT process) an efficiency of 70-75% can be reached. The SOFC and the SOFC/GT process are considered to be environment friendly regarding the discharges during operation. Especially formation of nitrogen oxides (NO{sub x}) is low since the SOFC temperatures are low compared to NO{sub x} formation temperatures. To study the whole environmental impact of the SOFC/GT process a life cycle assessment (LCA) is carried out to find the `hot spots` in the process` life cycle. Since the SOFC/GT process is under development today the collected data are mainly from literature and articles based on laboratory results. When performing the LCA only the SOFC-module and the gas turbine are included. A collection of data of all processes included, extraction of minerals, processing of raw material, production of the components, operation of the SOFC/GT process and transports between all these processes. These data are then added up and weighted in impact categories to evaluate the total environmental impact of the SOFC/GT process. All these steps are performed according to the ISO 14040-series. The stand-alone most contributing phase during the life cycle of the SOFC/GT process was found to be the production of the SOFC. All processes during the production of the SOFC are carried out under laboratory circumstances, which require more energy and materials than if the processes were commercialised and optimised. For the SOFC/GT process to be competitive with other energy converting processes regarding the discharges of emissions to the air, the use of

  14. Comparison of the updated solutions of the 6th dynamic AER Benchmark - main steam line break in a NPP with WWER-440

    International Nuclear Information System (INIS)

    Kliem, S.

    2003-01-01

    The 6 th dynamic AER Benchmark is used for the systematic validation of coupled 3D neutron kinetic/thermal hydraulic system codes. It was defined at The 10 th AER-Symposium. In this benchmark, a hypothetical double ended break of one main steam line at full power in a WWER-440 plant is investigated. The main thermal hydraulic features are the consideration of incomplete coolant mixing in the lower and upper plenum of the reactor pressure vessel and an asymmetric operation of the feed water system. For the tuning of the different nuclear cross section data used by the participants, an isothermal re-criticality temperature was defined. The paper gives an overview on the behaviour of the main thermal hydraulic and neutron kinetic parameters in the provided solutions. The differences in the updated solution in comparison to the previous ones are described. Improvements in the modelling of the transient led to a better agreement of a part of the results while for another part the deviations rose up. The sensitivity of the core power behaviour on the secondary side modelling is discussed in detail (Authors)

  15. Analysis of experimental characteristics of multistage steam-jet electors of steam turbines

    Science.gov (United States)

    Aronson, K. E.; Ryabchikov, A. Yu.; Brodov, Yu. M.; Brezgin, D. V.; Zhelonkin, N. V.; Murmanskii, I. B.

    2017-02-01

    A series of questions for specification of physical gas dynamics model in flow range of steam-jet unit and ejector computation methodology, as well as functioning peculiarities of intercoolers, was formulated based on analysis of experimental characteristics of multistage team-jet steam turbines. It was established that coefficient defining position of critical cross-section of injected flow depends on characteristics of the "sound tube" zone. Speed of injected flow within this tube may exceed that of sound, and pressure jumps in work-steam decrease at the same time. Characteristics of the "sound tube" define optimal axial sizes of the ejector. According to measurement results, the part of steam condensing in the first-stage coolant constitutes 70-80% of steam amount supplied into coolant and is almost independent of air content in steam. Coolant efficiency depends on steam pressure defined by operation of steam-jet unit of ejector of the next stage after coolant of steam-jet stage, temperature, and condensing water flow. As a rule, steam entering content of steam-air mixture supplied to coolant is overheated with respect to saturation temperature of steam in the mixture. This should be taken into account during coolant computation. Long-term operation causes changes in roughness of walls of the ejector's mixing chamber. The influence of change of wall roughness on ejector characteristic is similar to the influence of reverse pressure of the steam-jet stage. Until some roughness value, injection coefficient of the ejector stage operating in superlimiting regime hardly changed. After reaching critical roughness, the ejector switches to prelimiting operating regime.

  16. Steam generator with perfected dryers

    International Nuclear Information System (INIS)

    Fenet, J.C.

    1987-01-01

    This steam generator has vertically superposed array of steam dryers. These dryers return the steam flow of 180 0 . The return of the water is made by draining channels to the steam production zone [fr

  17. HTGR steam generator development

    International Nuclear Information System (INIS)

    Schuetzenduebel, W.G.; Hunt, P.S.; Weber, M.

    1976-01-01

    More than 40 gas-cooled reactor plants have produced in excess of 400 reactor years of operating experience which have proved a reasonably high rate of gas-cooled reactor steam generator availability. The steam generators used in these reactors include single U-tube and straight-tube steam generators as well as meander type and helically wound or involute tube steam generators. It appears that modern reactors are being equipped with helically wound steam generators of the once-through type as the end product of steam generator evolution in gas-cooled reactor plants. This paper provides a general overview of gas-cooled reactor steam generator evolution and operating experience and shows how design criteria and constraints, research and development, and experience data are factored into the design/development of modern helically wound tube steam generators for the present generation of gas-cooled reactors

  18. Steam Digest 2001

    Energy Technology Data Exchange (ETDEWEB)

    2002-01-01

    Steam Digest 2001 chronicles BestPractices Program's contributions to the industrial trade press for 2001, and presents articles that cover technical, financial and managerial aspects of steam optimization.

  19. Steam generator tube extraction

    International Nuclear Information System (INIS)

    Delorme, H.

    1985-05-01

    To enable tube examination on steam generators in service, Framatome has now developed a process for removing sections of steam generator tubes. Tube sections can be removed without being damaged for treating the tube section expanded in the tube sheet

  20. Steam sterilization does not require saturated steam

    NARCIS (Netherlands)

    van Doornmalen Gomez Hoyos, J. P.C.M.; Paunovic, A.; Kopinga, K.

    2017-01-01

    The most commonly applied method to sterilize re-usable medical devices in hospitals is steam sterilization. The essential conditions for steam sterilization are derived from sterilization in water. Microbiological experiments in aqueous solutions have been used to calculate various time–temperature

  1. WS-VLAM: A GT4 based workflow management system

    NARCIS (Netherlands)

    Wibisono, A.; Vasyunin, D.; Korkhov, V.; Zhao, Z.; Belloum, A.; de Laat, C.; Adriaans, P.; Hertzberger, B.

    2007-01-01

    Generic Grid middleware, e.g., Globus Toolkit 4 (GT4), provides basic services for scientific workflow management systems to discover, store and integrate workflow components. Using the state of the art Grid services can advance the functionality of workflow engine in orchestrating distributed Grid

  2. Adiponectin Single Nucleotide Polymorphism (+276G/T) and Its ...

    African Journals Online (AJOL)

    The present study was investigating the association between the single nucleotide polymorphism +276 G/T of the adiponectin gene with serum adiponectin level in patients with coronary artery disease (CAD). In this study 100 healthy controls and 100 Egyptian patients with coronary artery disease of both genders ...

  3. The Invisibility of Steam

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2014-01-01

    Almost everyone "knows" that steam is visible. After all, one can see the cloud of white issuing from the spout of a boiling tea kettle. In reality, steam is the gaseous phase of water and is invisible. What you see is light scattered from the tiny droplets of water that are the result of the condensation of the steam as its temperature…

  4. Strategies for steam

    International Nuclear Information System (INIS)

    Hennagir, T.

    1996-01-01

    This article is a review of worldwide developments in the steam turbine and heat recovery steam generator markets. The Far East is driving the market in HRSGs, while China is driving the market in orders placed for steam turbine prime movers. The efforts of several major suppliers are discussed, with brief technical details being provided for several projects

  5. Steam Digest: Volume IV

    Energy Technology Data Exchange (ETDEWEB)

    2004-07-01

    This edition of the Steam Digest is a compendium of 2003 articles on the technical and financial benefits of steam efficiency, presented by the stakeholders of the U.S. Department of Energy's BestPractices Steam effort.

  6. Steam Digest Volume IV

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-07-01

    This edition of the Steam Digest is a compendium of 2003 articles on the technical and financial benefits of steam efficiency, presented by the stakeholders of the U.S. Department of Energy's BestPractices Steam effort.

  7. Modification of Catalysts for Steam Reforming of Fluid Hydrocarbons. Research of Gas-Dynamic Duct Cooling Using Planar and Framework Catalysts (CD-ROM)

    National Research Council Canada - National Science Library

    Kuranov, Alexander L

    2005-01-01

    .... One way of fuel conversion is the catalytic steam reforming of hydrocarbon. This reaction has a large heat capacity and gives maximum quantity of molecular hydrogen among known reactions of hydrocarbons...

  8. Rotor scale model tests for power conversion unit of GT-MHR

    Energy Technology Data Exchange (ETDEWEB)

    Baxi, C.B.; Daugherty, R.; Shenoy, A. [General Atomics, 3550 General Atomics Court, CA (United States); Kodochigov, N.G.; Belov, S.E. [Experimental Design Bureau of Machine Building, N. Novgorad, RF (United States)

    2007-07-01

    The gas-turbine modular helium reactor (GT-MHR) combines a modular high-temperature gas-cooled reactor with a closed Brayton gas-turbine cycle power conversion unit (PCU) for thermal to electric energy conversion. The PCU has a vertical orientation and is supported on electromagnetic bearings (EMB). The Rotor Scale Model (RSM) Tests are intended to model directly the control of EMB and rotor-dynamic characteristics of the full-scale GT-MHR Turbo-machine. The objectives of the RSM tests are to: -1) confirm the EMB control system design for the GT-MHR turbo-machine over the full-range of operation, -2) confirm the redundancy and on-line maintainability features that have been specified for the EMBs, -3) provide a benchmark for validation of analytical tools that will be used for independent analyses of the EMB subsystem design, -4) provide experience with the installation, operation and maintenance of EMBs supporting multiple rotors with flexible couplings. As with the full-scale turbo-machine, the RSM will incorporate two rotors that are joined by a flexible coupling. Each of the rotors will be supported on one axial and two radial EMBs. Additional devices, similar in concept to radial EMBs, will be installed to simulate magnetic and/or mechanical forces representing those that would be seen by the exciter, generator, compressors and turbine. Overall, the length of the RSM rotor is about 1/3 that of the full-scale turbo-machine, while the diameter is approximately 1/5 scale. The design and sizing of the rotor is such that the number of critical speeds in the RSM are the same as in the full-scale turbo-machine. The EMBs will also be designed such that their response to rotor-dynamic forces is representative of the full-scale turbo-machine. (authors)

  9. Dynamic loads caused by pressure blasts, steam explosions, and earth quakes; Dynamische Belastungen durch Druckstoesse, Dampfexplosionen und Erdbeben

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, H H [SDK Ingenieurunternehmen GmbH, Basel (Switzerland)

    1998-11-01

    The paper deals with description of structures and the relevant dynamic loads. As to the structures, gas, fluid, or solid structures are to be considered. They determine the characteristic vibrational behaviour of the structures in the interconnected system. The excitation type determines the component that will be induced to change characteristic vibrational behaviour of the structure, depending on the load increasing time and the period of excitation. Three examples are given to illustrate the processes. (Water tank subject to quasi-seismic conditions; pipeline affected by blow-down; shut-off valve for a pipe). (orig./CB) [Deutsch] In diesem Beitrag soll auf die Erfassung der Strukturen und die Erfassung der dynamischen Belastungen eingegangen werden. Zur Erfassung der Strukturen sind `Gas-, Fluid- und Festkoerper-Strukturen` zu beachten. Sie bestimmen das Eigenschwingverhalten im Verbund. Die Erregung bestimmt nun, welcher Bereich aus dem Eigen-Schwingverhalten der Struktur ueber die Lastanstiegs-Zeit und die Zeitdauer der Erregung anregbar ist. Drei Beispiele sollen die Aufgabenstellung erlaeutern (Wasserbehaelter unter erdbebenaehnlichen Bedingungen; Rohrleitung unter `Blow-down-Belastung`; Absperrklappe fuer eine Rohrleitung). (orig./MM)

  10. Characteristics of steam jet impingement on annulus

    International Nuclear Information System (INIS)

    Yoon, Sang H.; Kim, Won J.; Suh, Kune Y.; Song, Chul H.

    2004-01-01

    The steam jet impingement occurs when the steam through the cold leg from the steam generator strikes the inner reactor barrel during the reflood phase of a loss-of-coolant accident (LOCA), which is a characteristic behavior for the APR1400 (Advanced Power Reactor 1400 MWe). In the cold leg break LOCA, the steam and water flows in the downcomer are truly multidimensional. The azimuthal velocity distribution of the steam flow has an important bearing on the thermal hydraulic phenomena such as the emergency coolant water direct bypass, sweepout, steam condensation, and so forth. The investigation of jet flow is required to determine the steam path and momentum reduction rate after the impingement. For the observation of the steam behavior near the break, the computational fluid dynamic (CFD) analysis has been carried out using CFX5.6. The flow visualization and analysis demonstrate the velocity profiles of the steam flow in the annulus region for the same boundary conditions. Pursuant to the CFD results, the micro-Pitot tubes were positioned at varying angles, and corrected for their sensitivity. The experiments were carried out to directly measure the pressure differential and to visualize the flow utilizing a smoke injection method. Results from this study are slated to be applied to MARS, which is a thermal hydraulic system code for the best-estimate analysis. The current one- or two-dimensional analysis in MARS was known to distort the local flow behavior. To enhance prediction capability of MARS, it is necessary to inspect the steam path in the break flow and mechanically simulate the momentum variation. The present experimental and analytical results can locally be applied to developing the engineering models of specific and essential phenomena. (author)

  11. Design of a SOFC/GT/SCs hybrid power system to supply a rural isolated microgrid

    International Nuclear Information System (INIS)

    Camblong, Haritza; Baudoin, Sylvain; Vechiu, Ionel; Etxeberria, Aitor

    2016-01-01

    Highlights: • A novel SOFC/GT/SCs HPS is connected to a rural microgrid through a 3LNPC inverter. • An operating strategy that maintains the SOFC power at its rated value is defined. • A robust digital controller that damps current oscillations is designed. • The efficiency, power quality, lifetime, and robustness of the HPS are considered. • An experimental test on an original HPS emulator validates the proposed solutions. - Abstract: The aim of this research study has been to design a Hybrid Power System (HPS) which works with biogas and whose main components are a Solid Oxide Fuel Cell (SOFC), a Gas microTurbine (GT), and a module of SuperCapacities (SCs). The HPS is the only power source of a rural isolated microgrid. Its structure, operating strategy, and controller have been designed considering the following criteria: efficiency, power quality, SOFC lifetime and robustness in stability and performance. The HPS structure includes a unique power converter, a 3-Level Neutral Point Clamped (3LNPC) inverter that connects the HPS to the AC microgrid. Regarding the selected operating strategy, it consists in regulating the SOFC power output to its rated value. Thus, the SCs and the GT must respond to the power demand variations. On the other hand, a study of the HPS shows that its dynamic behavior is not linear. Therefore, a special attention is put on designing a robust HPS controller. The control model is identified and the robust digital controller is designed using the “Tracking and Regulation with Independent Objectives” method. Simulation and experimental results show how the proposed structure, operating strategy, and controller allow ensuring a good behavior of the HPS from the point of view of the abovementioned four criteria.

  12. Response of the steam generator VVER 1000 to a steam line break

    International Nuclear Information System (INIS)

    Novotny, J.; Novotny, J. Jr.

    2003-01-01

    Dynamic effects of a steam line break in the weld of the steam pipe and the steam collector on the steam generator system are analyzed. Modelling of a steam line break may concern two cases. The steam line without a restraint and the steam line protected by a whip restraint with viscous elements applied at the postulated break cross-section. The second case is considered. Programme SYSTUS offers a special element the stiffness and viscous damping coefficients of which may be defined as dependent on the relative displacement and velocity of its nodes respectively. A circumferential crack is simulated by a sudden decrease of longitudinal and lateral stiffness coefficients of these special SYSTUS elements to zero. The computation has shown that one can simulate the pipe to behave like completely broken during a time interval of 0,0001 s or less. These elements are used to model the whip restraint with viscous elements and viscous dampers of the GERB type as well. In the case of a whip restraint model the stiffness coefficient-displacement relation and damping coefficient - velocity relation are chosen to fit the given characteristics of the restraint. The special SYSTUS elements are used to constitute Maxwell elements modelling the elasto-plastic and viscous properties of the GERB dampers applied to the steam generator. It has been ascertained that a steam line break at the postulated weld crack between the steam pipe and the steam generator collector cannot endanger the integrity of the system even in a case of the absence of a whip restraint effect. (author)

  13. GT-WGS: an efficient and economic tool for large-scale WGS analyses based on the AWS cloud service.

    Science.gov (United States)

    Wang, Yiqi; Li, Gen; Ma, Mark; He, Fazhong; Song, Zhuo; Zhang, Wei; Wu, Chengkun

    2018-01-19

    Whole-genome sequencing (WGS) plays an increasingly important role in clinical practice and public health. Due to the big data size, WGS data analysis is usually compute-intensive and IO-intensive. Currently it usually takes 30 to 40 h to finish a 50× WGS analysis task, which is far from the ideal speed required by the industry. Furthermore, the high-end infrastructure required by WGS computing is costly in terms of time and money. In this paper, we aim to improve the time efficiency of WGS analysis and minimize the cost by elastic cloud computing. We developed a distributed system, GT-WGS, for large-scale WGS analyses utilizing the Amazon Web Services (AWS). Our system won the first prize on the Wind and Cloud challenge held by Genomics and Cloud Technology Alliance conference (GCTA) committee. The system makes full use of the dynamic pricing mechanism of AWS. We evaluate the performance of GT-WGS with a 55× WGS dataset (400GB fastq) provided by the GCTA 2017 competition. In the best case, it only took 18.4 min to finish the analysis and the AWS cost of the whole process is only 16.5 US dollars. The accuracy of GT-WGS is 99.9% consistent with that of the Genome Analysis Toolkit (GATK) best practice. We also evaluated the performance of GT-WGS performance on a real-world dataset provided by the XiangYa hospital, which consists of 5× whole-genome dataset with 500 samples, and on average GT-WGS managed to finish one 5× WGS analysis task in 2.4 min at a cost of $3.6. WGS is already playing an important role in guiding therapeutic intervention. However, its application is limited by the time cost and computing cost. GT-WGS excelled as an efficient and affordable WGS analyses tool to address this problem. The demo video and supplementary materials of GT-WGS can be accessed at https://github.com/Genetalks/wgs_analysis_demo .

  14. Condensation of steam

    International Nuclear Information System (INIS)

    Prisyazhniuk, V.A.

    2002-01-01

    An equation for nucleation kinetics in steam condensation has been derived, the equation taking into account the concurrent and independent functioning of two nucleation mechanisms: the homogeneous one and the heterogeneous one. The equation is a most general-purpose one and includes all the previously known condensation models as special cases. It is shown how the equation can be used in analyzing the process of steam condensation in the condenser of an industrial steam-turbine plant, and in working out new ways of raising the efficiency of the condenser, as well as of the steam-turbine plant as a whole. (orig.)

  15. EPRI steam generator programs

    International Nuclear Information System (INIS)

    Martel, L.J.; Passell, T.O.; Bryant, P.E.C.; Rentler, R.M.

    1977-01-01

    The paper describes the current overall EPRI steam generator program plan and some of the ongoing projects. Because of the recent occurrence of a corrosion phenomenon called ''denting,'' which has affected a number of operating utilities, an expanded program plan is being developed which addresses the broad and urgent needs required to achieve improved steam generator reliability. The goal of improved steam generator reliability will require advances in various technologies and also a management philosophy that encourages conscientious efforts to apply the improved technologies to the design, procurement, and operation of plant systems and components that affect the full life reliability of steam generators

  16. Environment-friendly type energy and coordinated community development project. Feasibility study for industrialization of high efficiency waste-fired power generation system (industrial refuse derived fuel and gas turbine combined type); Kankyo chowagata energy community keisei sokushin. Kokoritsu haikibutsu hatsuden (sangyo RDF GT fukugogata) jigyoka FS chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    High efficiency power generation, which is useful for promoting the environment-friendly type energy and coordinated community, is investigated by combining a steam turbine power generation system using the PS-RDF (paper sludge-refuse derived fuel) and a gas turbine (GT) combined cycle. Industrialization plan for processing PS in low cost has been made to ensure the profitability by participating the wholesale power supply under the law of electric power industry. This combined system is similar to the so-called super power generation using municipal garbage, but the lower temperature of steam from GT waste heat boilers (WHB) is super-heated by the flue gas from RDF boiler, which is called advanced power generation system (A.S.S.). The total power generation capacity is 149,000 kW, which consists of three 35,000 kW units of GT and one 44,000 kW unit of steam turbine. When comparing the combined system (A.S.S.) and usual one with the independent installation of the RDF steam power generation system and a GT combined cycle, the A.S.S. provides the repowering efficiency of 7,600 kW output with exactly the same quantity of fuel input as usual one. 71 figs., 31 tabs.

  17. Steampunk: Full Steam Ahead

    Science.gov (United States)

    Campbell, Heather M.

    2010-01-01

    Steam-powered machines, anachronistic technology, clockwork automatons, gas-filled airships, tentacled monsters, fob watches, and top hats--these are all elements of steampunk. Steampunk is both speculative fiction that imagines technology evolved from steam-powered cogs and gears--instead of from electricity and computers--and a movement that…

  18. Safety Picks up "STEAM"

    Science.gov (United States)

    Roy, Ken

    2016-01-01

    This column shares safety information for the classroom. STEAM subjects--science, technology, engineering, art, and mathematics--are essential for fostering students' 21st-century skills. STEAM promotes critical-thinking skills, including analysis, assessment, categorization, classification, interpretation, justification, and prediction, and are…

  19. Steam-water separator

    International Nuclear Information System (INIS)

    Modrak, T.M.; Curtis, R.W.

    1978-01-01

    A two-stage steam-water separating device is introduced, where the second stage is made as a cyclone separator. The water separated here is collected in the first stage of the inner tube and is returned to the steam raising unit. (TK) [de

  20. Steam power plant

    International Nuclear Information System (INIS)

    Campbell, J.W.E.

    1981-01-01

    This invention relates to power plant forced flow boilers operating with water letdown. The letdown water is arranged to deliver heat to partly expanded steam passing through a steam reheater connected between two stages of the prime mover. (U.K.)

  1. International co-operation in developing the GT-MHR

    International Nuclear Information System (INIS)

    La Bar, M.P.; Simon, W.A.

    1997-01-01

    In the Fall of 1995, driven by budget constraints and anti-nuclear sentiments, the US government decided to discontinue financial support of the Gas Turbine-Modular Helium Reactor (GT-MHR). At that time, significant work was underway with participation of several vendors with specialized expertise in various aspects of the GT-MHR. Fortunately the US government provided for documenting the design and development status through an orderly close-out program. Concurrent elimination of government restrictions opened the door for broader international cooperation. Discussion between General Atomics and the Russian Ministry of Atomic Energy (MINATOM), in the summer of 1994, led to an agreement on a jointly funded design and development program for the GT-MHR. The program is initially focused on the burning of weapons plutonium that becomes available from dismantled nuclear weapons. The long term goal is to utilize the same design for commercial applications - using uranium fuel. This program took advantage of existing technologies and facilities in the US and Russia, but right from the beginning left the door open for broader international cooperation. Accordingly, in January 1996, FRAMATOME has joined the ongoing effort. Discussions are underway with other international entities to join this program. The program is proceeding well. Several Russian laboratories/design organizations are participating with GA and FRAMATOME. Significant improvements in the power conversion system design are a clear example of the benefit of the cooperative effort. Further work needs to be done to confirm fuel and components prior to full deployment, etc., providing ample opportunities for international cooperation in many areas

  2. Uligevægt mellem familie og arbejdsliv

    DEFF Research Database (Denmark)

    Boje, Thomas P.; Ejrnæs, Anders

    2015-01-01

    Kapitlet beskriver og diskuterer de strategier, som bliver anvendt i familiepolitikken i Danmark såvel som i udvalgte europæiske lande med det formål at sikre en bedre ligevægt mellem de krav, som stilles til forældrene i arbejdslivet og i familien i form af omsorg for børn. Kapitlet afsluttes me...... beskrivelse af en familiepolitisk typologi, og hvordan relationen mellem familie og arbejde kommer til udtryk i de forskellige europæiske velfærdsregimer....

  3. Development of GT-MGR plant power conversion unit design

    International Nuclear Information System (INIS)

    Kostin, V.I.; Kodochigov, N.G.; Belov, S.E.; Vasyaev, A.V.; Golovko, V.F.; Shenoj, A.

    2007-01-01

    The General Atomic Company (USA) and the Pilot Design Bureau for Machine-Building (Russia) are involved in the efforts to design the GT-MGR modular helium cooled reactor and the energy conversion unit with the direct gas turbine cycle. The reactor capacity is equal to 600 MW, it is cooled by helium under 7 MPa pressure. The energy conversion unit consists of a gas turbine, a recuperator, preliminary and intermediate coolers, a generator. The turbine shaft rotation frequency is equal to 4400 rotation/minute. One analyzed the alternate designs of the energy conversion unit to choose its configuration [ru

  4. An Isothermal Steam Expander for an Industrial Steam Supplying System

    Directory of Open Access Journals (Sweden)

    Chen-Kuang Lin

    2015-01-01

    Full Text Available Steam is an essential medium used in the industrial process. To ensure steam quality, small and middle scale boilers are often adopted. However, because a higher steam pressure (compared to the necessary steam pressure is generated, the boiler’s steam pressure will be reduced via a pressure regulator before the steam is directed through the process. Unfortunately, pressure is somewhat wasted during the reducing process. Therefore, in order to promote energy efficiency, a pressure regulator is replaced by a steam expander. With this steam expander, the pressure will be transformed into mechanical energy and extracted during the expansion process. A new type of isothermal steam expander for an industrial steam supplying system will be presented in the paper. The isothermal steam expander will improve the energy efficiency of a traditional steam expander by replacing the isentropic process with an isothermal expansion process. With this, steam condensation will decrease, energy will increase, and steam quality will be improved. Moreover, the mathematical model of the isothermal steam expander will be established by using the Schmidt theory, the same principle used to analyze Stirling engines. Consequently, by verifying the correctness of the theoretical model for the isothermal steam expander using experimental data, a prototype of 100 c.c. isothermal steam expander is constructed.

  5. Modeling and Simulation of U-tube Steam Generator

    Science.gov (United States)

    Zhang, Mingming; Fu, Zhongguang; Li, Jinyao; Wang, Mingfei

    2018-03-01

    The U-tube natural circulation steam generator was mainly researched with modeling and simulation in this article. The research is based on simuworks system simulation software platform. By analyzing the structural characteristics and the operating principle of U-tube steam generator, there are 14 control volumes in the model, including primary side, secondary side, down channel and steam plenum, etc. The model depends completely on conservation laws, and it is applied to make some simulation tests. The results show that the model is capable of simulating properly the dynamic response of U-tube steam generator.

  6. Parametric Optimization of Biomass Steam-and-Gas Plant

    Directory of Open Access Journals (Sweden)

    V. Sednin

    2013-01-01

    Full Text Available The paper contains a parametric analysis of the simplest scheme of a steam-and gas plant for the conditions required for biomass burning. It has been shown that application of gas-turbine and steam-and-gas plants can significantly exceed an efficiency of steam-power supply units which are used at the present moment. Optimum thermo-dynamical conditions for application of steam-and gas plants with the purpose to burn biomass require new technological solutions in the field of heat-exchange equipment designs.

  7. Steam generator life management

    International Nuclear Information System (INIS)

    Tapping, R.L.; Nickerson, J.; Spekkens, P.; Maruska, C.

    1998-01-01

    Steam generators are a critical component of a nuclear power reactor, and can contribute significantly to station unavailability, as has been amply demonstrated in Pressurized Water Reactors (PWRs). CANDU steam generators are not immune to steam generator degradation, and the variety of CANDU steam generator designs and tube materials has led to some unexpected challenges. However, aggressive remedial actions, and careful proactive maintenance activities, have led to a decrease in steam generator-related station unavailability of Canadian CANDUs. AECL and the CANDU utilities have defined programs that will enable existing or new steam generators to operate effectively for 40 years. Research and development work covers corrosion and mechanical degradation of tube bundles and internals, chemistry, thermal hydraulics, fouling, inspection and cleaning, as well as provision for specially tool development for specific problem solving. A major driving force is development of CANDU-specific fitness-for-service guidelines, including appropriate inspection and monitoring technology to measure steam generator condition. Longer-range work focuses on development of intelligent on-line monitoring for the feedwater system and steam generator. New designs have reduced risk of corrosion and fouling, are more easily inspected and cleaned, and are less susceptible to mechanical damage. The Canadian CANDU utilities have developed programs for remedial actions to combat degradation of performance (Gentilly-2, Point Lepreau, Bruce A/B, Pickering A/B), and have developed strategic plans to ensure that good future operation is ensured. This report shows how recent advances in cleaning technology are integrated into a life management strategy, discusses downcomer flow measurement as a means of monitoring steam generator condition, and describes recent advances in hideout return as a life management tool. The research and development program, as well as operating experience, has identified

  8. Thermodynamics of the silica-steam system

    Energy Technology Data Exchange (ETDEWEB)

    Krikorian, Oscar H [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-01

    In most nuclear cratering and cavity formation applications, the working fluid in the expanding cavity consists primarily of vaporized silica and steam. The chemical reaction products of silica and steam under these conditions are not known, although it is known that silica is very volatile in the presence of high-pressure steam under certain geologic conditions and in steam turbines. A review is made of work on the silica-steam system in an attempt to determine the vapor species that exist, and to establish the associated thermo-dynamic data. The review indicates that at 600-900 deg K and 1-100 atm steam pressure, Si(OH){sub 4} is the most likely silicon-containing gaseous species. At 600-900 deg. K and 100-1000 atm steam, Si{sub 2}O(OH){sub 6} is believed to predominate, whereas at 1350 deg K and 2000-9000 atm, a mixture of Si(OH){sub 4} and Si{sub 2}O(OH){sub 6} is consistent with the observed volatilities. In work at 1760 deg. K in which silica was reacted either with steam at 0.5 and 1 atm, or with gaseous mixtures of H{sub 2}/H{sub 2}O and O{sub 2}/H{sub 2}O at 1 atm total pressure, only part of the volatility could be accounted for by Si(OH){sub 4}. Hydrogen was found to greatly enhance the volatility of silica, and oxygen to suppress it. The species most likely to explain this behavior is believed to be SiO(OH). A number of other species may also be significant under these conditions. Thermodynamic data have been estimated for all species considered. The Si-OH bond dissociation energy is found to be {approx}117 kcal/mole in both Si(OH){sub 4} and Si{sub 2}O(OH){sub 6}. (author)

  9. Porsche GT3 R Hybrid. Prototype and race lab; Porsche GT3 R Hybrid. Technologietraeger und rollendes Labor

    Energy Technology Data Exchange (ETDEWEB)

    Armbruster, Daniel [Porsche Motorsport, Weissach (Germany); Hennings, Stephan [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Inst. fuer Fahrzeugsystemtechnik

    2011-05-15

    Hybrid technology is one of the key technologies for coping with changing future requirements in the area of individual mobility. This technology is already being used in small, mid-size and upper class vehicles and is perceived by the public as environmentally friendly. To date, however, no hybrid drive concepts suitable for mass production have been available for sports cars, such as the Porsche 911. In order to answer questions about the optimum design of hybrid drive systems for high-performance vehicles and about the use of future technologies in motor racing, Porsche Motorsport therefore developed the GT3 R Hybrid. (orig.)

  10. Steam microturbines in distributed cogeneration

    CERN Document Server

    Kicinski, Jan

    2014-01-01

    This book presents the most recent trends and concepts in power engineering, especially with regard to prosumer and civic energy generation. In so doing, it draws widely on his experience gained during the development of steam microturbines for use in small combined heat and power stations based on the organic Rankine cycle (CHP-ORC). Major issues concerning the dynamic properties of mechanical systems, in particular rotating systems, are discussed, and the results obtained when using unconventional bearing systems, presented. Modeling and analysis of radial-flow and axial-flow microturbines a

  11. Status of GT-MHR with emphasis on the power conversion system

    International Nuclear Information System (INIS)

    Neylan, A.J.; Silady, F.A.; Kohler, B.P.; Lomba, D.; Rose, R.

    1996-01-01

    The conceptual design of the Gas Turbine-Modular Helium Reactor (GT-MHR) has made significant progress in the past year. Evaluation of an external versus internal (submerged) generator and modifications as a result of an internal seal task force were completed. Significant progress was also made on the design of the generator utilizing existing technology. Conceptual design of the turbocompressor was confirmed, including extensive evaluation of the entire turbomachine (turbocompressor and generator) rotor dynamics. Results concluded in a revised configuration for the location of magnetic bearings supporting the entire machine. Integration of the turbomachine with the recuperator, precooler, intercooler and internal ducts and seals progressed to improved maintenance and operation. This resulted in some changes and improvements in the overall arrangement of the power conversion module. The paper also provides a summary of the fuel and safety assessment progress. (author). 6 refs, 7 figs, 3 tabs

  12. Rotor scale model tests for power conversion unit of GT-MHR

    Energy Technology Data Exchange (ETDEWEB)

    Baxi, C.B., E-mail: baxicb1130@hotmail.com [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Telengator, A.; Razvi, J. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)

    2012-10-15

    The gas turbine modular helium reactor (GT-MHR) combines a modular high-temperature gas-cooled reactor (HTGR) nuclear heat source with a closed Brayton gas-turbine cycle power conversion unit (PCU) for thermal to electric energy conversion. The PCU has a vertical orientation and is supported on electromagnetic bearings (EMB). The rotor scale model (RSM) tests are intended to directly model the control of EMB and rotor dynamic characteristics of the full-scale GT-MHR turbo-machine (TM). The objectives of the RSM tests are to: Bullet Confirm the EMB control system design for the GT-MHR turbo machine over the full-range of operation. Bullet Confirm the redundancy and on-line maintainability features that have been specified for the EMBs. Bullet Provide a benchmark for validation of analytical tools that will be used for independent analyses of the EMB subsystem design. Bullet Provide experience with the installation, operation and maintenance of EMBs supporting multiple rotors with flexible couplings. As with the full-scale TM, the RSM incorporates two rotors that are joined by a flexible coupling. Each of the rotors is supported on one axial and two radial EMBs. Additional devices, similar in concept to radial EMBs, are installed to simulate magnetic and/or mechanical forces representing those that would be seen by the exciter, generator, compressors and turbine. Overall, the lengths of the RSM rotor is about 1/3rd that of the full-scale TM, while the diameters are approximately 1/5th scale. The design and sizing of the rotor is such that the number and values of critical speeds in the RSM are the same as in the full-scale TM. The EMBs are designed such that their response to rotor dynamic forces is representative of the full-scale TM. The fabrication and assembly of the RSM was completed at the end of 2008. All start up adjustments were finished in December 2009. To-date the generator rotor has been supported in the EMBs and rotated up to 1800 rpm. Final tests are

  13. Steam generator tube failures

    International Nuclear Information System (INIS)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service

  14. French steam generator

    International Nuclear Information System (INIS)

    Remond, A.

    1986-01-01

    After recalling the potential damage mode of tubes of steam generator, the author recalls the safety criteria used in France. The improvements and the process of damage prejudice and reparation for tubular bundle are presented [fr

  15. Steam purity in PWRs

    International Nuclear Information System (INIS)

    Hopkinson, J.

    1982-01-01

    Impurities enter the secondary loop of the PWR through both makeup water from lake or well and cooling-water leaks in the condenser. These impurities can be carried to the steam generator, where they cause corrosion deposits to form. Corrosion products in steam are swept further through the system and become concentrated at the point in the low-pressure turbine where steam begins to condense. Several plants have effectively reduced impurities, and therefore corrosion, by installing a demineralizer for the makeup water, a resin-bed system to clean condensed steam from the condenser, and a deaerator to remove oxygen from the water and so lower the risk of system metal oxidation. 5 references, 1 figure

  16. Liquid metal steam generator

    International Nuclear Information System (INIS)

    Wolowodiuk, W.

    1975-01-01

    A liquid metal heated steam generator is described which in the event of a tube failure quickly exhausts out of the steam generator the products of the reaction between the water and the liquid metal. The steam is generated in a plurality of bayonet tubes which are heated by liquid metal flowing over them between an inner cylinder and an outer cylinder. The inner cylinder extends above the level of liquid metal but below the main tube sheet. A central pipe extends down into the inner cylinder with a centrifugal separator between it and the inner cylinder at its lower end and an involute deflector plate above the separator so that the products of a reaction between the liquid metal and the water will be deflected downwardly by the deflector plate and through the separator so that the liquid metal will flow outwardly and away from the central pipe through which the steam and gaseous reaction products are exhausted. (U.S.)

  17. Steam cleaning device

    International Nuclear Information System (INIS)

    Karaki, Mikio; Muraoka, Shoichi.

    1985-01-01

    Purpose: To clean complicated and long objects to be cleaned having a structure like that of nuclear reactor fuel assembly. Constitution: Steams are blown from the bottom of a fuel assembly and soon condensated initially at the bottom of a vertical water tank due to water filled therein. Then, since water in the tank is warmed nearly to the saturation temperature, purified water is supplied from a injection device below to the injection device above the water tank on every device. In this way, since purified water is sprayed successively from below to above and steams are condensated in each of the places, the entire fuel assembly elongated in the vertical direction can be cleaned completely. Water in the reservoir goes upward like the steam flow and is drained together with the eliminated contaminations through an overflow pipe. After the cleaning has been completed, a main steam valve is closed and the drain valve is opened to drain water. (Kawakami, Y.)

  18. Steam generator water lancing

    International Nuclear Information System (INIS)

    Kamler, F.; Schneider, W.

    1992-01-01

    The tubesheet and tube support plate deposits in CANDU steam generators are notable for their hardness. Also notable is the wide variety of steam generator access situations. Because of the sludge hardness and the difficulty of the access, traditional water lancing processes which directed jets from the central tube free lane or from the periphery of the bundle have proven unsuitable. This has led to the need for some very unique inter tube water lancing devices which could direct powerful water jets directly onto the deposits. This type of process was applied to the upper broached plates of the Bruce A steam generators, which had become severely blocked. It has since been applied to various other steam generator situations. This paper describes the flexlance equipment development, qualification, and performance in the various CANDU applications. 4 refs., 2 tabs., 7 figs

  19. Steam-water separator

    International Nuclear Information System (INIS)

    Modrak, T.M.; Curtis, R.W.

    1978-01-01

    The steam-water separator connected downstream of a steam generator consists of a vertical centrifugal separator with swirl blades between two concentric pipes and a cyclone separator located above. The water separated in the cyclone separator is collected in the inner tube of the centrifugal separator which is closed at the bottom. This design allows the overall height of the separator to be reduced. (DG) [de

  20. FRONT AXLE OF MERCEDES AMG GT. MODELLING IN AUTODESK INVENTOR

    Directory of Open Access Journals (Sweden)

    COROLENCU Eduard – Narcis

    2017-05-01

    Full Text Available This paper analyzes the front axle of the Mercedes AMG GT model, as so as the graphical representation of the axle and of the subassemblies of suspension system and steering system, using the AutoCAD and Autodesk Inventor software. The paper include the steps for made the 3D model of the front axle in order to highlight the advantages of suspension and steering system, the function of this systems and methods for manufacturing of these. The 3D model presents a suite of complex surfaces. This type of surfaces is often designed with non-analytical means. The main commands and options used in Autodesk Inventor software were presented and explained. All the component parts of the front axle were modelled and assembled according to their functional role. Finally, the models were rendered in order to have a realistic appearance.

  1. WBP: The wood Brazilian BIG-GT demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    Carpentieri, E. [Companhia Hidro Eletrica do Sao Francisco, Recife (Brazil)

    1993-12-31

    Brazil is one of the leading countries in the use of renewable energy. Most of its electricity comes from hydro power, about 200,000 barrels a day of ethanol from sugar cane is used as fuel, around 38% of the pig iron, and 20% of the steel production, uses charcoal as a reducing medium. Located in the tropics, with the sun shining all year round, and with its vast territory, the Country may be regarded as having all the basic conditions to develop a modern Biomass for Electricity industry. The conjunction of those characteristics with, the necessity of developing new energy resources for electricity production in the Northeast of the Country, the results of the studies made by Princeton University, Shell and Chesf, the progress achieved by the BIG-GT (Biomass Integrated Gasification Gas Turbine) technology in Europe, and the organization of the Global Environment Facility (GEF), provided the unique opportunity for the implementation of a commercial demonstration in Brazil. This paper describes the idea, the scope, the technical challenges, and actual status of development of the WBP, a project which aims to demonstrate the commercial viability of the BIG-GT technology. It also highlights, the project management structure, the role of the GEF, World Bank and of the United Nations Development Program (UNDP), and the participation of the Brazilian Federal Government, through the Ministry of Science and Technology (MCT). Finally it describes the Participants (ELETROBRAS, CVRD, CIENTEC, SHELL, and CHESF), their role in the project, and how the group was formed and operates.

  2. Experimental study of steam condensation regime map for simplified spargers

    International Nuclear Information System (INIS)

    Kim, Y. S.; Yoon, Y. J.; Song, C. H.; Park, C. K.; Kang, H. S.; Jun, H. K.

    2003-01-01

    An experimental study was conducted to produce a condensation regime map for single-hole and 4-hole steam spargers using GIRLS facility. The regime map for a single-hole sparger was derived using parameters such as the frequency and magnitude of the dynamic pressure. For 4-hole sparager, the regime map was derived using the trends of sound and dynamic pressure. Using the single-hole and 4-hole data, a steam jet condensation regime map was suggested with respect to pool temperature and steam mass flux

  3. Digital simulation for nuclear once-through steam generators

    International Nuclear Information System (INIS)

    Chen, A.T.

    1976-01-01

    Mathematical models for calculating the dynamic response of the Oconee type once through steam generator (OTSG) and the integral economizer once through steam generator (IEOTSG) was developed and presented in this dissertation. Linear and nonlinear models of both steam generator types were formulated using the state variable, lumped parameter approach. Transient and frequency responses of system parameters were calculated for various perturbations from both the primary coolant side and the secondary side. Transients of key parameters, including primary outlet temperature, superheated steam outlet temperature, boiling length/subcooled length and steam pressure, were generated, compared and discussed for both steam generator types. Frequency responses of delta P/sub s//deltaT/sub pin/ of the linear OTSG model were validated by using the dynamic testing results obtained at the Oconee I nuclear power station. A sensitivity analysis in both the time and the frequency domains was performed. It was concluded that the mathematical and computer models developed in this dissertation for both the OTSG and the IEOTSG are suitable for overall plant performance evaluation and steam generator related component/system design analysis for nuclear plants using either type of steam generator

  4. Evaluation of Cathode Air Flow Transients in a SOFC/GT Hybrid System Using Hardware in the Loop Simulation.

    Science.gov (United States)

    Zhou, Nana; Yang, Chen; Tucker, David

    2015-02-01

    Thermal management in the fuel cell component of a direct fired solid oxide fuel cell gas turbine (SOFC/GT) hybrid power system can be improved by effective management and control of the cathode airflow. The disturbances of the cathode airflow were accomplished by diverting air around the fuel cell system through the manipulation of a hot-air bypass valve in open loop experiments, using a hardware-based simulation facility designed and built by the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The dynamic responses of the fuel cell component and hardware component of the hybrid system were studied in this paper.

  5. Steam temperature variation behind a turbine steam separator-superheater during NPP start-up

    International Nuclear Information System (INIS)

    Lejzerovich, A.Sh.; Melamed, A.D.

    1979-01-01

    To determine necessary parameters of the steam temperature automatic regulator behind the steam separator-rheater supe (SSS) of an NPP turbine the static and dynamic characteristics of the temperature change behind the SSS were studied experimentally. The measurements were carried out at the K-220-44 turbine of the Kolskaja NPP in the case of both varying turbine loads and the flow rate of the heating vapor. Disturbances caused by the opening of the regulating valve at the inlet of the heating vapor are investigated as well. It is found that due to a relatively high inertiality of the SSS a rather simple structure of the start-up steam temperature regulators behind the SSS in composition with automatated driving systems of the turbine start-up without regard for the change of the dynamic characteristics can be used

  6. Steam explosion studies review

    International Nuclear Information System (INIS)

    Hwang, Moon Kyu; Kim, Hee Dong

    1999-03-01

    When a cold liquid is brought into contact with a molten material with a temperature significantly higher than the liquid boiling point, an explosive interaction due to sudden fragmentation of the melt and rapid evaporation of the liquid may take place. This phenomenon is referred to as a steam explosion or vapor explosion. Depending upon the amount of the melt and the liquid involved, the mechanical energy released during a vapor explosion can be large enough to cause serious destruction. In hypothetical severe accidents which involve fuel melt down, subsequent interactions between the molten fuel and coolant may cause steam explosion. This process has been studied by many investigators in an effort to assess the likelihood of containment failure which leads to large scale release of radioactive materials to the environment. In an effort to understand the phenomenology of steam explosion, extensive studies has been performed so far. The report presents both experimental and analytical studies on steam explosion. As for the experimental studies, both small scale tests which involve usually less than 20 g of high temperature melt and medium/large scale tests which more than 1 kg of melt is used are reviewed. For the modelling part of steam explosions, mechanistic modelling as well as thermodynamic modelling is reviewed. (author)

  7. Numerical study on steam injection in a turbocompound diesel engine for waste heat recovery

    International Nuclear Information System (INIS)

    Zhao, Rongchao; Li, Weihua; Zhuge, Weilin; Zhang, Yangjun; Yin, Yong

    2017-01-01

    Highlights: • Steam injection was adopted in a turbocompound engine to further recover waste heat. • Thermodynamics model for the turbocompound engine was established and calibrated. • Steam injection at CT inlet obtained lower engine BSFC than injection at PT inlet. • The optimal injected steam mass at different engine speeds was presented. • Turbocompounding combined with steam injection can reduce the BSFC by 6.0–11.2%. - Abstract: Steam injection and turbocompouding are both effective methods for engine waste heat recovery. The fuel saving potential obtained by the combination of the two methods is not clear. Based on a turbocompound engine developed in the previous study, the impacts of pre-turbine steam injection on the fuel saving potentials of the turbocompound engine were investigated in this paper. Firstly, thermodynamic cycle model for the baseline turbocompound engine is established using commercial software GT-POWER. The cycle model is calibrated with the experiment data of the turbocompound engine and achieves high accuracy. After that, the influences of steam mass flow rate, evaporating pressure and injection location on the engine performance are studied. In addition, the impacts of hot liquid water injection are also investigated. The results show that steam injection at the turbocharger turbine inlet can reduce the turbocompound engine BSFC at all speed conditions. The largest fuel reduction 6.15% is obtained at 1000 rpm condition. However, steam injection at power turbine inlet can only lower the BSFC at high speed conditions. Besides, it is found that hot liquid water injection in the exhaust cannot improve the engine performance. When compared with the conventional turbocharged engine, the combination of turbocompounding and steam injection can reduce the BSFC by 6.0–11.2% over different speeds.

  8. Thermoeconomic Modeling and Parametric Study of Hybrid Solid Oxide Fuel Cell â Gas Turbine â Steam Turbine Power Plants Ranging from 1.5 MWe to 10 MWe

    OpenAIRE

    Arsalis, Alexandros

    2007-01-01

    Detailed thermodynamic, kinetic, geometric, and cost models are developed, implemented, and validated for the synthesis/design and operational analysis of hybrid solid oxide fuel cell (SOFC) â gas turbine (GT) â steam turbine (ST) systems ranging in size from 1.5 MWe to 10 MWe. The fuel cell model used in this thesis is based on a tubular Siemens-Westinghouse-type SOFC, which is integrated with a gas turbine and a heat recovery steam generator (HRSG) integrated in turn with a steam turbi...

  9. Using Dynamic Simulation to Evaluate Attemperator Operation in a Natural Gas Combined Cycle With Duct Burners in the Heat Recovery Steam Generator

    Energy Technology Data Exchange (ETDEWEB)

    Liese, Eric [National Energy Technology Laboratory,Department of Energy,Systems Engineering and Analysis Division,Morgantown, WV 26507e-mail: eric.liese@netl.doe.gov; Zitney, Stephen E. [National Energy Technology Laboratory,Department of Energy,Systems Engineering and Analysis Division,Morgantown, WV 26507e-mail: stephen.zitney@netl.doe.gov

    2017-09-26

    A generic training simulator of a natural gas combined cycle was modified to match operations at a real plant. The objective was to use the simulator to analyze cycling operations of the plant. Initial operation of the simulator revealed the potential for saturation conditions in the final high pressure superheater as the attemperator tried to control temperature at the superheater outlet during gas turbine loading and unloading. Subsequent plant operational data confirmed simulation results. Multiple simulations were performed during loading and unloading of the gas turbine to determine operational strategies that prevented saturation and increased the approach to saturation temperature. The solutions included changes to the attemperator temperature control setpoints and strategic control of the steam turbine inlet pressure control valve.

  10. Steam generator arrangement

    International Nuclear Information System (INIS)

    Ssinegurski, E.

    1981-01-01

    A steam flow path arrangement for covering the walls of the rear gas pass of a steam generator is disclosed. The entire flow passes down the sidewalls with a minor portion then passing up through the rear wall to a superheater inlet header at an intermediate elevation. The major portion of the flow passes up the front wall and through hanger tubes to a roof header. From there the major portion passes across the roof and down the rear wall to the superheater inlet header at the intermediate elevation

  11. Helium turbomachine design for GT-MHR power plant

    International Nuclear Information System (INIS)

    McDonald, C.F.; Orlando, R.J.

    1994-07-01

    The power conversion system in the gas turbine modular helium reactor (GT-MHR) power plant is based on a highly recuperated closed Brayton cycle. The major component in the direct cycle system is a helium closed-cycle gas turbine rated at 286 MW(e). The rotating group consists of an intercooled helium turbocompressor coupled to a synchronous generator. The vertical rotating assembly is installed in a steel vessel, together with the other major components (i.e., recuperator, precooler, intercooler, and connecting ducts and support structures). The rotor is supported on an active magnetic bearing system. The turbine operates directly on the reactor helium coolant, and with a temperature of 850 degree C (1562 degree F) the plant efficiency is over 47%. This paper addresses the design and development planning of the helium turbomachine, and emphasizes that with the utilization of proven technology, this second generation nuclear power plant could be in service in the first decade of the 21st century

  12. Steam generator sludge removal apparatus

    International Nuclear Information System (INIS)

    Schafer, B.W.; Werner, C.E.; Klahn, F.C.

    1992-01-01

    The present invention relates to equipment for cleaning steam generators and in particular to a high pressure fluid lance for cleaning sludge off the steam generator tubes away from an open tube lane. 6 figs

  13. Steam generators - problems and prognosis

    International Nuclear Information System (INIS)

    Tapping, R.L.

    1997-05-01

    Steam-generator problems, largely a consequence of corrosion and fouling, have resulted in increased inspection requirements and more regulatory attention to steam-generator integrity. In addition, utilities have had to develop steam-generator life-management strategies, including cleaning and replacement, to achieve design life. This paper summarizes the pertinent data to 1993/1994, and presents an overview of current steam-generator management practices. (author)

  14. Steam reforming of ethanol

    DEFF Research Database (Denmark)

    Trane-Restrup, Rasmus; Dahl, Søren; Jensen, Anker Degn

    2013-01-01

    Steam reforming (SR) of oxygenated species like bio-oil or ethanol can be used to produce hydrogen or synthesis gas from renewable resources. However, deactivation due to carbon deposition is a major challenge for these processes. In this study, different strategies to minimize carbon deposition...

  15. Consolidated nuclear steam generator

    International Nuclear Information System (INIS)

    Jabsen, F.S.; Schluderberg, D.C.; Paulson, A.E.

    1978-01-01

    An improved system of providing power has a unique generating means for nuclear reactors with a number of steam generators in the form of replaceable modular units of the expendable type to attain the optimum in effective and efficient vaporization of fluid during the generating power. The system is most adaptable to undrground power plants and marine usage

  16. Steam generators and furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Swoboda, E

    1978-04-01

    The documents published in 1977 in the field of steam generators for conventional thermal power plants are classified according to the following subjects: power industry and number of power plants, planning and operation, design and construction, furnaces, environmental effects, dirt accumulation and corrosion, conservation and scouring, control and automation, fundamental research, and materials.

  17. Watt steam governor stability

    Science.gov (United States)

    Denny, Mark

    2002-05-01

    The physics of the fly-ball governor, introduced to regulate the speed of steam engines, is here analysed anew. The original analysis is generalized to arbitrary governor geometry. The well-known stability criterion for the linearized system breaks down for large excursions from equilibrium; we show approximately how this criterion changes.

  18. Steam purity in PWRs

    International Nuclear Information System (INIS)

    Hopkinson, J.; Passell, T.

    1982-01-01

    Reports that 2 EPRI studies of PWRs prove that impure steam triggers decay of turbine metals. Reveals that EPRI is attempting to improve steam monitoring and analysis, which are key steps on the way to deciding the most cost-effective degree of steam purity, and to upgrade demineralizing systems, which can then reliably maintain that degree of purity. Points out that 90% of all cracks in turbine disks have occurred at the dry-to-wet transition zone, dubbed the Wilson line. Explains that because even very clean water contains traces of chemical impurities with concentrations in the parts-per-billion range, Crystal River-3's secondary loop was designed with even more purification capability; a deaerator to remove oxygen and prevent oxidation of system metals, and full-flow resin beds to demineralize 100% of the secondary-loop water from the condenser. Concludes that focusing attention on steam and water chemistry can ward off cracking and sludge problems caused by corrosion

  19. Creep-rupture, steam oxidation and recovery behaviours upon dynamic transients up to 1300 C of cold-worked 304 stainless steel tubes dedicated to nuclear core fuel cladding

    International Nuclear Information System (INIS)

    Portier, L.; Brachet, J.C.; Vandenberghe, V.; Guilbert, T.; Lezaud-Chaillioux, V.; Bernard, C.; Rabeau, V.

    2011-01-01

    An ambitious mechanical tests program was conducted on the fuel rod cladding of the CABRI facility between 2004 and 2009 to re-evaluate the cladding tubes materials behaviour. As an offspring of this major scientific investment several conclusions of interest could be drawn on the 304 stainless steel material. In particular, the specific behaviour of the materials during hypothetical and extreme 'dry-out' conditions was investigated. In such a scenario, the cladding tube materials should experience a very brief incursion at high temperatures, in a steam environment, up to 1300 C, before cladding rewetting. Some of the measurements performed in the range of interest for the safety case were on purpose developed beyond the conservatively safe domain. Some of the results obtained for these non-conventional heating rates, pressures and temperature ranges will be presented. First in order to assess the high temperature creep-rupture material behaviour under internal pressure upon dynamic transient conditions, tests have been performed on cold-worked 304 stainless cladding tubes in a steam environment, for heating rates up to 100 C*s -1 and pressure ramp rates up to 10 bar*s -1 thanks to the use of the EDGAR facility. Other tests performed at a given pressure allowed us to check the steady-state secondary creep rate of the materials in the 1100-1200 C temperature range. It was also possible to determine the rupture strength value and the failure mode as a function of the thermal and pressure loading history applied. It is worth noticing that, for very specific conditions, a surprising pure intergranular brittle failure mode of the clad has been observed. Secondly, in order to check the materials oxidation resistance of the materials, two-side steam oxidation tests have been performed at 1300 C, using the DEZIROX facility. It was shown that, thanks to the use of Ring Compression tests, the 304 cladding tube keeps significant ductility for oxidation times up to at least

  20. Steam table routines for the simulation of nuclear power plants

    International Nuclear Information System (INIS)

    Hall, C.A.; Mutafelija, B.A.; Rapp, J.P.

    1976-01-01

    The dynamic simulation of nuclear power generating stations requires evaluation of a large number of steam and water properties at every integration time step. Some of the interpolation/approximation methods presently used are described with particular emphasis on the use of the bilinear transfinite interpolation method. The fundamental requirements for the steam table routines are outlined and different approaches are compared. The superiority of the bilinear transfinite interpolation method is discussed. The use of the steam table functions in real-time simulation is of particular interest

  1. Comparison of Raw Acceleration from the GENEA and ActiGraph™ GT3X+ Activity Monitors

    Directory of Open Access Journals (Sweden)

    Dinesh John

    2013-10-01

    Full Text Available Purpose: To compare raw acceleration output of the ActiGraph™ GT3X+ and GENEA activity monitors. Methods: A GT3X+ and GENEA were oscillated in an orbital shaker at frequencies ranging from 0.7 to 4.0 Hz (ten 2-min trials/frequency on a fixed radius of 5.08 cm. Additionally, 10 participants (age = 23.8 ± 5.4 years wore the GT3X+ and GENEA on the dominant wrist and performed treadmill walking (2.0 and 3.5 mph and running (5.5 and 7.5 mph and simulated free-living activities (computer work, cleaning a room, vacuuming and throwing a ball for 2-min each. A linear mixed model was used to compare the mean triaxial vector magnitude (VM from the GT3X+ and GENEA at each oscillation frequency. For the human testing protocol, random forest machine-learning technique was used to develop two models using frequency domain (FD and time domain (TD features for each monitor. We compared activity type recognition accuracy between the GT3X+ and GENEA when the prediction model was fit using one monitor and then applied to the other. Z-statistics were used to compare the proportion of accurate predictions from the GT3X+ and GENEA for each model. Results: GENEA produced significantly higher (p < 0.05, 3.5 to 6.2% mean VM than GT3X+ at all frequencies during shaker testing. Training the model using TD input features on the GENEA and applied to GT3X+ data yielded significantly lower (p < 0.05 prediction accuracy. Prediction accuracy was not compromised when interchangeably using FD models between monitors. Conclusions: It may be inappropriate to apply a model developed on the GENEA to predict activity type using GT3X+ data when input features are TD attributes of raw acceleration.

  2. Multi-color lightcurve observation of the asteroid (163249) 2002 GT

    Science.gov (United States)

    Oshima, M.; Abe, S.

    2014-07-01

    NASA's Deep Impact/EPOXI spacecraft plans to encounter the asteroid (163249) 2002 GT, classified as a PHA (Potentially Hazardous Asteroid), on January 4, 2020. However, the taxonomic type and spin state of 2002 GT remain to be determined. We have carried out ground-based multi-color (B-V-R-I) lightcurve observations taking advantage of the 2002 GT Characterization Campaign by NASA. Multi-color lightcurve measurements allow us to estimate the rotation period and obtain strong constraints on the shape and pole orientation. Here we found that the rotation period of 2002 GT is estimated to be 3.7248 ± 0.1664 h. In mid-2013, 2002 GT passed at 0.015 au from the Earth, resulting an exceptional opportunity for ground-based characterization. Using the 0.81-m telescope of the Tenagra Observatory (110°52'44.8''W, +31°27'44.4''N, 1312 m) in Arizona, USA, and the Johnson-Cousins BVRI filters, we have found lightcurves of 2002 GT (Figure). The Tenagra II 0.81-m telescope is used for research of the Hayabusa2 target Asteroid (162173) 1999 JU_3. The lightcurves (relative magnitude) show that the rotation period of 2002 GT, the target of NASA's Deep Impact/EPOXI spacecraft, is estimated to be 3.7248 ± 0.1664 hr. On June 9, 2013, we had 7 hours of ground-based observations on 2002 GT from 4:00 to 11:00 UTC. The number of comparison stars for differential photometry was 34. Because of tracking the fast-moving asteroid, it was necessary to have the same comparison star among the fields of vision. We have also obtained absolute photometry of 2002 GT on June 13, 2013.

  3. Dynamic simulation of a reboiler

    International Nuclear Information System (INIS)

    Moeck, E.O.; McMorran, P.D.

    1977-07-01

    A hybrid-computer simulation of reboiler dynamics was prepared, comprising models of steam condensation in tubes, heat conduction, steam generation, a surge tank, steam transmission line and flow-control valve. Time and frequency responses were obtained to illustrate the dynamics of this multivariable process. (author)

  4. Steam Turbine Control Valve Stiction Effect on Power System Stability

    International Nuclear Information System (INIS)

    Halimi, B.

    2010-01-01

    One of the most important problems in power system dynamic stability is low frequency oscillations. This kind of oscillation has significant effects on the stability and security of the power system. In some previous papers, a fact was introduced that a steam pressure continuous fluctuation in turbine steam inlet pipeline may lead to a kind of low frequency oscillation of power systems. Generally, in a power generation plant, steam turbine system composes of some main components, i.e. a boiler or steam generator, stop valves, control valves and turbines that are connected by piping. In the conventional system, the turbine system is composed with a lot of stop and control valves. The steam is provided by a boiler or steam generator. In an abnormal case, the stop valve shuts of the steal flow to the turbine. The steam flow to the turbine is regulated by controlling the control valves. The control valves are provided to regulate the flow of steam to the turbine for starting, increasing or decreasing the power, and also maintaining speed control with the turbine governor system. Unfortunately, the control valve has inherent static friction (stiction) nonlinearity characteristics. Industrial surveys indicated that about 20-30% of all control loops oscillate due to valve problem caused by this nonlinear characteristic. In this paper, steam turbine control valve stiction effect on power system oscillation is presented. To analyze the stiction characteristic effect, firstly a model of control valve and its stiction characteristic are derived by using Newton's laws. A complete tandem steam prime mover, including a speed governing system, a four-stage steam turbine, and a shaft with up to for masses is adopted to analyze the performance of the steam turbine. The governor system consists of some important parts, i.e. a proportional controller, speed relay, control valve with its stiction characteristic, and stem lift position of control valve controller. The steam turbine has

  5. Steam generators in PWR's

    International Nuclear Information System (INIS)

    Michel, R.

    1974-01-01

    The steam generator of the PWR operates according to the principle of natural circulation. It consists of a U-shaped tube bundle whose free ends are welded to a bottom plate. The tube bundle is surrounded by a cylinder jacket which has slots closely above the bottom or tube plate. The feed water mixed with boiling water enters the tube bundle through these slots. Because of its buoyancy, the steam-water mixture flows upwards. Below the tube plate there are chambers for distributing and collecting pressurized water separated by means of a partition wall. By omitting some tubes, a free alloy is created so that the tubes in the center get sufficient water, too. By asymmetrical arrangement of the partition wall it is further possible to limit the tube alloy only to the inlet side for pressurized water. The flow over the tube plate is thus improved on the inlet side. (DG) [de

  6. Vertical steam generator

    International Nuclear Information System (INIS)

    Cuda, F.; Kondr, M.; Kresta, M.; Kusak, V.; Manek, O.; Turon, S.

    1982-01-01

    A vertical steam generator for nuclear power plants and dual purpose power plants consists of a cylindrical vessel in which are placed heating tubes in the form upside-down U. The heating tubes lead to the jacket of the cylindrical collector placed in the lower part of the steam generator perpendicularly to its vertical axis. The cylindrical collector is divided by a longitudinal partition into the inlet and outlet primary water sections of the heating tubes. One ends of the heating tube leads to the jacket of the collector for primary water feeding and the second ends of the heating tubes into the jacket of the collector which feeds and offtakes primary water from the heating tubes. (B.S.)

  7. Development of teaching material to integrate GT-POWER into combustion courses for IC engine simulations.

    Science.gov (United States)

    2009-02-01

    The main objective of this project was to develop instructional engineering projects that utilize the newly-offered PACE software GT-POWER for engine simulations in combustion-related courses at the Missouri University of Science and Technology. Stud...

  8. Steam generator life management

    International Nuclear Information System (INIS)

    King, P.; McGillivray, R.; Reinhardt, W.; Millman, J.; King, B.; Schneider, W.

    2003-01-01

    'Full-Text:' Steam Generator Life Management responsibility embodies doing whatever is necessary to maintain the steam generation equipment of a nuclear plant in effective, reliable service. All comes together in that most critical deliverable, namely the submission of the documentation which wins approval for return to service after an outage program. Life management must address all aspects of SG reliability over the life of the plant. Nevertheless, the life management activities leading up to return to service approval is where all of it converges. Steam Generator Life Management activities entail four types of work, all equally important in supporting the objective of successful operation. These activities are i) engineering functions; including identification of inspection and maintenance requirements, outage planning and scope definition plus engineering assessment, design and analysis as necessary to support equipment operation, ii) fitness of service work; including the expert evaluation of degradation mechanisms, disposition of defects for return to service or not, and the fitness for service analysis as required to justify ongoing operation with acceptable defects, iii) inspection work; including large scale eddy current inspection of tubing, the definition of defect size and character, code inspections of pressure vessel integrity and visual inspections for integrity and iv) maintenance work; including repairs, retrofits, cleaning and modifications, all as necessary to implement the measures defined during activities i) through iii). The paper discusses the approach and execution of the program for the achievement of the above objectives and particularly of items i) and ii). (author)

  9. What is geothermal steam worth?

    International Nuclear Information System (INIS)

    Thorhallsson, S.; Ragnarsson, A.

    1992-01-01

    Geothermal steam is obtained from high-temperature boreholes, either directly from the reservoir or by flashing. The value of geothermal steam is similar to that of steam produced in boilers and lies in its ability to do work in heat engines such as turbines and to supply heat for a wide range of uses. In isolated cases the steam can be used as a source of chemicals, for example the production of carbon dioxide. Once the saturated steam has been separated from the water, it can be transported without further treatment to the end user. There are several constraints on its use set by the temperature of the reservoir and the chemical composition of the reservoir fluid. These constraints are described (temperature of steam, scaling in water phase, gas content of steam, well output) as are the methods that have been adopted to utilize this source of energy successfully. Steam can only be transported over relatively short distances (a few km) and thus has to be used close to the source. Examples are given of the pressure drop and sizing of steam mains for pipelines. The path of the steam from the reservoir to the end user is traced and typical cost figures given for each part of the system. The production cost of geothermal steam is estimated and its sensitivity to site-specific conditions discussed. Optimum energy recovery and efficiency is important as is optimizing costs. The paper will treat the steam supply system as a whole, from the reservoir to the end user, and give examples of how the site-specific conditions and system design have an influence on what geothermal steam is worth from the technical and economic points of view

  10. A Receding Horizon Controller for the Steam Generator Water Level

    International Nuclear Information System (INIS)

    Na, Man Gyun; Lee, Yoon Joon

    2003-01-01

    In this work, the receding horizon control method was used to control the water level of nuclear steam generators and applied to two linear models and also a nonlinear model of steam generators. A receding horizon control method is to solve an optimization problem for finite future steps at current time and to implement the first optimal control input as the current control input. The procedure is then repeated at each subsequent instant. The dynamics of steam generators is very different according to power levels. The receding horizon controller is designed by using a reduced linear steam generator model fixed over a certain power range and applied to a Westinghouse-type (U-tube recirculating type) nuclear steam generator. The proposed controller designed at a fixed power level shows good performance for any other power level within this power range. The steam generator shows actually nonlinear characteristics. Therefore, the proposed algorithm is implemented for a nonlinear model of the nuclear steam generator to verify its real performance and also shows good responses

  11. INTEGRAL/JEM-X detection of fading emission from GT Mus

    DEFF Research Database (Denmark)

    Fiocchi, M.; Chenevez, J.; Sguera, V.

    2015-01-01

    On November 15th 2015 the MAXI/GSC detected a big flare from the RS CVn star GT Mus with a flux of ~100 mCrab in the 2-20 keV energy band. (ATel #8285). During recent INTEGRAL observations of the Musca region performed between 17 Nov 16:08 and 18 Nov 00:05 (UTC) the source GT Mus was within the f...

  12. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal

    2014-03-01

    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  13. Steam generators, turbines, and condensers. Volume six

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Volume six covers steam generators (How steam is generated, steam generation in a PWR, vertical U-tube steam generators, once-through steam generators, how much steam do steam generators make?), turbines (basic turbine principles, impulse turbines, reaction turbines, turbine stages, turbine arrangements, turbine steam flow, steam admission to turbines, turbine seals and supports, turbine oil system, generators), and condensers (need for condensers, basic condenser principles, condenser arrangements, heat transfer in condensers, air removal from condensers, circulating water system, heat loss to the circulating water system, factors affecting condenser performance, condenser auxiliaries)

  14. Steam turbines for the future

    International Nuclear Information System (INIS)

    Trassl, W.

    1988-01-01

    Approximately 75% of the electrical energy produced in the world is generated in power plants with steam turbines (fossil and nuclear). Although gas turbines are increasingly applied in combined cycle power plants, not much will change in this matter in the future. As far as the steam parameters and the maximum unit output are concerned, a certain consolidation was noted during the past decades. The standard of development and mathematical penetration of the various steam turbine components is very high today and is applied in the entire field: For saturated steam turbines in nuclear power plants and for steam turbines without reheat, with reheat and with double reheat in fossil-fired power plants and for steam turbines with and without reheat in combined cycle power plants. (orig.) [de

  15. Static and dynamic modelling of gas turbines in advanced cycles

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Jan-Olof

    1998-12-01

    Gas turbines have been in operation for at least 50 years. The engine is used for propulsion of aircraft and high speed ships. It is used for power production in remote locations and for peak load and emergency situations. Gas turbines have been used in combined cycles for 20 to 30 years. Highly efficient power plants based on gas turbines are a competitive option for the power industry today. The thermal efficiency of the simple cycle gas turbine has increased due to higher turbine inlet temperatures and improved compressor and expander designs. Equally important are the improved cycles in which the gas turbine operates. One example is the combined cycle that uses steam for turbine cooling. Steam is extracted from the bottoming cycle, then used as airfoil coolant in a closed loop and returned to the bottoming cycle. The Evaporative Gas Turbine (EvGT), also known as the Humid Air Turbine (HAT), is another advanced cycle. A mixture of air and water vapour is used as working media. Air from the compressor outlet is humidified and then preheated in a recuperator prior to combustion. The static and dynamic performance is changed when the gas turbine is introduced in an evaporative cycle. The cycle is gaining in popularity, but so far it has not been demonstrated. A Swedish joint program to develop the cycle has been in operation since 1993. As part of the program, a small pilot plant is being erected at the Lund Institute of Technology (LTH). The plant is based on a 600 kW gas turbine, and demonstration of the EvGT cycle started autumn 1998 and will continue, in the present phase, for one year. This thesis presents static and dynamic models for traditional gas turbine components, such as, the compressor, combustor, expander and recuperator. A static model for the humidifier is presented, based on common knowledge for atmospheric humidification. All models were developed for the pilot plant at LTH with the objective to support evaluation of the process and individual

  16. Kids Inspire Kids for STEAM

    OpenAIRE

    Fenyvesi, Kristof; Houghton, Tony; Diego-Mantecón, José Manuel; Crilly, Elizabeth; Oldknow, Adrian; Lavicza, Zsolt; Blanco, Teresa F.

    2017-01-01

    Abstract The goal of the Kids Inspiring Kids in STEAM (KIKS) project was to raise students' awareness towards the multi- and transdisciplinary connections between the STEAM subjects (Science, Technology, Engineering, Arts & Mathematics), and make the learning about topics and phenomena from these fields more enjoyable. In order to achieve these goals, KIKS project has popularized the STEAM-concept by projects based on the students inspiring other students-approach and by utilizing new tec...

  17. Imitative modeling automatic system Control of steam pressure in the main steam collector with the influence on the main Servomotor steam turbine

    Science.gov (United States)

    Andriushin, A. V.; Zverkov, V. P.; Kuzishchin, V. F.; Ryzhkov, O. S.; Sabanin, V. R.

    2017-11-01

    The research and setting results of steam pressure in the main steam collector “Do itself” automatic control system (ACS) with high-speed feedback on steam pressure in the turbine regulating stage are presented. The ACS setup is performed on the simulation model of the controlled object developed for this purpose with load-dependent static and dynamic characteristics and a non-linear control algorithm with pulse control of the turbine main servomotor. A method for tuning nonlinear ACS with a numerical algorithm for multiparametric optimization and a procedure for separate dynamic adjustment of control devices in a two-loop ACS are proposed and implemented. It is shown that the nonlinear ACS adjusted with the proposed method with the regulators constant parameters ensures reliable and high-quality operation without the occurrence of oscillations in the transient processes the operating range of the turbine loads.

  18. Analysis of fast reactor steam generator performance

    International Nuclear Information System (INIS)

    Hulme, G.; Curzon, A.F.

    1992-01-01

    A computer model for the prediction of flow and temperature fields within a fast reactor steam generator unit is described. The model combines a commercially available computational fluid dynamics (CFD) solver (PHOENICS) with a steam-tube calculation and provides solutions for the fully coupled flow and temperature fields on both the shell side and the tube side. The model includes the inlet and outlet headers and the bottom end stagnant zone. It also accounts for the effects of support grids and edge-gaps. Two and three dimensional and transient calculations have been performed for both straight tube and J-tube units. Examples of the application of the model are presented. (7 figures) (Author)

  19. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1984-10-01

    A review of the performance of steam generator tubes in 116 water-cooled nuclear power reactors showed that tubes were plugged at 54 (46 percent) of the reactors. The number of tubes removed from service decreased from 4 692 (0.30 percent) in 1981 to 3 222 (0.20 percent) in 1982. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that have used only volatile treatment, with or without condensate demineralization

  20. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Tapping, R.L.; Stipan, L.

    1992-03-01

    A survey of steam generator operating experience for 1986 has been carried out for 184 pressurized water and pressurized heavy-water reactors, and 1 water-cooled, graphite-moderated reactor. Tubes were plugged at 75 of the reactors (40.5%). In 1986, 3737 tubes were plugged (0.14% of those in service) and 3148 tubes were repaired by sleeving. A small number of reactors accounted for the bulk of the plugged tubes, a phenomenon consistent with previous years. For 1986, the available tubesheet sludge data for 38 reactors has been compiled into tabular form, and sludge/deposit data will be incorporated into all future surveys

  1. Steam generator auxiliary systems

    International Nuclear Information System (INIS)

    Heinz, A.

    1982-01-01

    The author deals with damage and defect types obtaining in auxiliary systems of power plants. These concern water/steam auxiliary systems (feed-water tank, injection-control valves, slide valves) and air/fluegas auxiliary systems (blowers, air preheaters, etc.). Operating errors and associated damage are not dealt with; by contrast, weak spots are pointed out which result from planning and design. Damage types and events are collected in statistics in order to facilitate damage evaluation for arriving at improved design solutions. (HAG) [de

  2. DEMONSTRATION BULLETIN STEAM ENHANCED REMEDIATION STEAM TECH ENVIRONMENTAL SERVICES, INC.

    Science.gov (United States)

    Steam Enhanced Remediation is a process in which steam is injected into the subsurface to recover volatile and semivolatile organic contaminants. It has been applied successfully to recover contaminants from soil and aquifers and at a fractured granite site. This SITE demonstra...

  3. Steam generators: critical components in nuclear steam supply systems

    Energy Technology Data Exchange (ETDEWEB)

    Stevens-Guille, P D

    1974-02-28

    Steam generators are critical components in power reactors. Even small internal leaks result in costly shutdowns for repair. Surveys show that leaks have affected one half of all water-cooled reactors in the world with steam generators. CANDU reactors have demonstrated the highest reliability. However, AECL is actively evolving new technology in design, manufacture, inspection and operation to maintain reliability. (auth)

  4. Utilization of waste heat from GT-MHR for power generation in organic Rankine cycles

    International Nuclear Information System (INIS)

    Yari, Mortaza; Mahmoudi, S.M.S.

    2010-01-01

    The gas turbine-modular helium reactor (GT-MHR) is currently being developed by an international consortium. In this power plant, circulating helium that has to be compressed in a single or two successive stages cools the reactor core. For thermodynamic reasons, these compression stages require pre-cooling of the helium to about 26 deg. C through the use of intercooler and pre-cooler in which water is used to cool the helium. Considerable thermal energy (∼300 MWth) is thus dissipated in these components. This thermal energy is then rejected to a heat sink. For different designs, the temperature ranges of the helium in the intercooler and pre-cooler could be about 100 and 150 deg. C, respectively. These are ideal energy sources to be used in an organic Rankine cycles for power generation. This study examines the performance of a gas-cooled nuclear power plant with closed Brayton cycle (CBC) combined with two organic Rankine cycles (ORC). More attention was paid to the irreversibilities generated in the combined cycle. Individual models are developed for each component through applications of the first and second laws of thermodynamics. The effects of the turbine inlet temperature, compressor pressure ratio, evaporator temperature and temperature difference in the evaporator on the first- and second-law efficiencies and on the exergy destruction rate of the combined cycle were studied. Finally the combined cycle was optimized thermodynamically using the EES (Engineering Equation Solver) software. Based on identical operating conditions, a comparison between the GT-MHR/ORC and a simple GT-MHR cycle is also made. It was found that both the first- and second-law efficiencies of GT-MHR/ORC cycle are about 3%-points higher than that of the simple GT-MHR cycle. Also, the exergy destruction rate for GT-MHR/ORC cycle is about 5% lower than that of the GT-MHR cycle.

  5. Steam-Generator Integrity Program/Steam-Generator Group Project

    International Nuclear Information System (INIS)

    1982-10-01

    The Steam Generator Integrity Program (SGIP) is a comprehensive effort addressing issues of nondestructive test (NDT) reliability, inservice inspection (ISI) requirements, and tube plugging criteria for PWR steam generators. In addition, the program has interactive research tasks relating primary side decontamination, secondary side cleaning, and proposed repair techniques to nondestructive inspectability and primary system integrity. The program has acquired a service degraded PWR steam generator for research purposes. This past year a research facility, the Steam Generator Examination Facility (SGEF), specifically designed for nondestructive and destructive examination tasks of the SGIP was completed. The Surry generator previously transported to the Hanford Reservation was then inserted into the SGEF. Nondestructive characterization of the generator from both primary and secondary sides has been initiated. Decontamination of the channelhead cold leg side was conducted. Radioactive field maps were established in the steam generator, at the generator surface and in the SGEF

  6. Can mt2 much-gt mb2 arise from small corrections in four-family models

    International Nuclear Information System (INIS)

    Mendel, R.R.; Margolis, B.; Therrien, E.; Valin, P.

    1989-01-01

    This paper proposes a general dynamical scheme capable of explaining naturally the main properties of the observed spectrum, namely the strong inter-family mass hierarchies and the mixing pattern. The authors illustrate these properties in the three-family case with a simple toy model. There is an indication that large values of m t may be required in order to obtain |V by |much-lt|V bc ; the fact the m 2 much-gt m 2 could be due to small corrections in a four-family model where m' ∼ m'. The authors point out possible natural explanations for the small mass of the e, μ and τ neutrinos in the three and four family cases

  7. Electricity from geothermal steam

    Energy Technology Data Exchange (ETDEWEB)

    Wheatcroft, E L.E.

    1959-01-01

    The development of the power station at Wairakei geothermal field is described. Wairakei is located at the center of New Zealand's volcanic belt, which lies within a major graben which is still undergoing some degree of downfaulting. A considerable number of wells, some exceeding 610 m, have been drilled. Steam and hot water are produced from both deep and shallow wells, which produce at gauge pressures of 1.5 MPa and 0.6 MPa, respectively. The turbines are fed by low, intermediate, and high pressure mains. The intermediate pressure turbine bank was installed as a replacement for a heavy water production facility which had originally been planned for the development. Stage 1 includes a 69 MW plant, and stage 2 will bring the capacity to 150 MW. A third stage, which would bring the output up to 250 MW had been proposed. The second stage involves the installation of more high pressure steam turbines, while the third stage would be powered primarily by hot water flashing. Generation is at 11 kV fed to a two-section 500 MVA board. Each section of the board feeds through a 40 MVA transformer to a pair of 220 V transmission lines which splice into the North Island grid. Other transformers feed 400 V auxiliaries and provide local supply.

  8. Steam generator materials

    International Nuclear Information System (INIS)

    Kim, Joung Soo; Han, J. H.; Kim, H. P.; Lim, Y. S.; Lee, D. H.; Suh, J. H.; Hwang, S. S.; Hur, D. H.; Kim, D. J.; Kim, Y. H.

    2002-05-01

    In order to keep the nuclear power plant(NPP)s safe and increase their operating efficiency, axial stress corrosion cracking(SCC)(IGA/IGSCC, PWSCC, PbSCC) test techniques were developed and SCC property data of the archive steam generator tubing materials having been used in nuclear power plants operating in Korea were produced. The data obtained in this study were data-based, which will be used to clarify the damage mechanisms, to operate the plants safely, and to increase the lifetime of the tubing. In addition, the basic technologies for the improvement of the SCC property of the tubing materials, for new SCC inhibition, for damaged tube repair, and for manufacturing processes of the tubing were developed. In the 1 phase of this long term research, basic SCC test data obtained from the archive steam generator tubing materials used in NPPs operating in Korea were established. These basic technologies developed in the 1 phase will be used in developing process optimization during the 2 phase in order to develop application technologies to the field nuclear power plants

  9. Steam hydrocarbon cracking and reforming

    NARCIS (Netherlands)

    Golombok, M.

    2004-01-01

    Many industrial chemical processes are taught as distinct contrasting reactions when in fact the unifying comparisons are greater than the contrasts. We examine steam hydrocarbon reforming and steam hydrocarbon cracking as an example of two processes that operate under different chemical reactivity

  10. A thermodynamic study of waste heat recovery from GT-MHR using organic Rankine cycles

    International Nuclear Information System (INIS)

    Yari, Mortaza; Mahmoudi, S.M.S.

    2011-01-01

    This paper presents an investigation on the utilization of waste heat from a gas turbine-modular helium reactor (GT-MHR) using different arrangements of organic Rankine cycles (ORCs) for power production. The considered organic Rankine cycles were: simple organic Rankine cycle (SORC), ORC with internal heat exchanger (HORC) and regenerative organic Rankine cycle (RORC). The performances of the combined cycles were studied from the point of view of first and second-laws of thermodynamics. Individual models were developed for each component and the effects of some important parameters such as compressor pressure ratio, turbine inlet temperature, and evaporator and environment temperatures on the efficiencies and on the exergy destruction rate were studied. Finally the combined cycles were optimized thermodynamically using the EES (Engineering Equation Solver) software. Based on the identical operating conditions for the GT-MHR cycle, a comparison between the three combined cycles and a simple GT-MHR cycle is also were made. This comparison was also carried out from the point of view of economics. The GT-MHR/SORC combined cycle proved to be the best among all the cycles from the point of view of both thermodynamics and economics. The efficiency of this cycle was about 10% higher than that of GT-MHR alone. (orig.)

  11. Steam generator reliability improvement project

    International Nuclear Information System (INIS)

    Blomgren, J.C.; Green, S.J.

    1987-01-01

    Upon successful completion of its research and development technology transfer program, the Electric Power Research Institute's Steam Generator Owners Group (SGOG II) will disband in December 1986 and be replaced in January 1987 by a successor project, the Steam Generator Reliability Project (SGRP). The new project, funded in the EPRI base program, will continue the emphasis on reliability and life extension that was carried forward by SGOG II. The objectives of SGOG II have been met. Causes and remedies have been identified for tubing corrosion problems, such as stress corrosion cracking and pitting, and steam generator technology has been improved in areas such as tube wear prediction and nondestructive evaluation (NDE). These actions have led to improved reliability of steam generators. Now the owners want to continue with a centrally managed program that builds on what has been learned. The goal is to continue to improve steam generator reliability and solve small problems before they become large problems

  12. Steam generator reliability improvement project

    International Nuclear Information System (INIS)

    Blomgren, J.C.; Green, S.J.

    1987-01-01

    Upon successful completion of its research and development technology transfer program, the Electric Power Research Institute's (EPRI's) Steam Generator Owners Group (SGOG II) will disband in December 1986, and be replaced in January 1987, by a successor project, the Steam Generator Reliability Project (SGRP). The new project, funded in the EPRI base program, will continue to emphasize reliability and life extension, which were carried forward by SGOG II. The objectives of SGOG II have been met. Causes and remedies have been identified for tubing corrosion problems such as stress corrosion cracking and pitting, and steam generator technology has been improved in areas such as tube wear prediction and nondestructive evaluation. These actions have led to improved reliability of steam generators. Now the owners want to continue with a centrally managed program that builds on what has been learned. The goal is to continue to improve steam generator reliability and to solve small problems before they become large problems

  13. Steam generator tube integrity program

    International Nuclear Information System (INIS)

    Dierks, D.R.; Shack, W.J.; Muscara, J.

    1996-01-01

    A new research program on steam generator tubing degradation is being sponsored by the U.S. Nuclear Regulatory Commission (NRC) at Argonne National Laboratory. This program is intended to support a performance-based steam generator tube integrity rule. Critical areas addressed by the program include evaluation of the processes used for the in-service inspection of steam generator tubes and recommendations for improving the reliability and accuracy of inspections; validation and improvement of correlations for evaluating integrity and leakage of degraded steam generator tubes, and validation and improvement of correlations and models for predicting degradation in steam generator tubes as aging occurs. The studies will focus on mill-annealed Alloy 600 tubing, however, tests will also be performed on replacement materials such as thermally-treated Alloy 600 or 690. An overview of the technical work planned for the program is given

  14. Investigation of SAGD steam trap control in two and three dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Edmunds, N. R. [Clearwater Engineering, AB (Canada)

    1998-12-31

    Steam trap production control has been traditionally recommended for steam-assisted gravity drainage (SAGD) operations. This study examines the relationship between producing steam trap subcool settings and related parameters of interest such as fluid level, pressure, production rate, and profitability for a prototype Athabasca reservoir. Study results indicate that the steam trap dynamics are far more complex than hitherto imagined, that 3-D simulations predict significantly lower production rates than 2-D simulations, and that these variations have implications for all aspects of SAGD engineering, including process optimization, production operations and performance analysis. 10 refs., 2 tabs., 15 figs.

  15. Effects of the steam chest on steamhammer analysis for nuclear piping systems

    International Nuclear Information System (INIS)

    Luk, C.

    1975-01-01

    When applying the method of characteristics for the steamhammer analysis of a nuclear piping system, if the dynamic fluid behavior in the steam chest is not considered, the boundary condition thus formulated to describe the time-dependent fluid behavior of the steam chest would lead to numerical unstable solution. To overcome this difficulty, the dynamic fluid behavior in the steam chest can be described by a single degree mechanical system. The corresponding flow conditions there are then determined by the time-step amplification method. This dynamic boundary condition reduces the calculated steamhammer loads and helps avoid numerical instability problems in the computing procedure. 4 refs

  16. Application of Integrated Neural Network Method to Fault Diagnosis of Nuclear Steam Generator

    International Nuclear Information System (INIS)

    Zhou Gang; Yang Li

    2009-01-01

    A new fault diagnosis method based on integrated neural networks for nuclear steam generator (SG) was proposed in view of the shortcoming of the conventional fault monitoring and diagnosis method. In the method, two neural networks (ANNs) were employed for the fault diagnosis of steam generator. A neural network, which was used for predicting the values of steam generator operation parameters, was taken as the dynamics model of steam generator. The principle of fault monitoring method using the neural network model is to detect the deviations between process signals measured from an operating steam generator and corresponding output signals from the neural network model of steam generator. When the deviation exceeds the limit set in advance, the abnormal event is thought to occur. The other neural network as a fault classifier conducts the fault classification of steam generator. So, the fault types of steam generator are given by the fault classifier. The clear information on steam generator faults was obtained by fusing the monitoring and diagnosis results of two neural networks. The simulation results indicate that employing integrated neural networks can improve the capacity of fault monitoring and diagnosis for the steam generator. (authors)

  17. Flow Instabilities and Main Steam Line Vibrations in a Pressurized Water Reactor

    International Nuclear Information System (INIS)

    Henriksson, Mats; Westin, Johan; Granhall, Tord; Andersson, Lars; Bjerke, Lars-Erik

    2002-01-01

    Severe vibrational problems occurred in the main steam system of a PWR nuclear power plant, about 18 months after a steam generator replacement had been carried out. The magnitude of the vibrations reached levels at which the operators had to reduce power in order to stay within the operating limits imposed by the nuclear inspectorate. To solve the problem the following analyses methods were employed: - Testing the influence on vibration level from different modes of plant operation; - Analyses of plant measurement data; - Calculations of: hydraulic behaviour of the system, structural dynamic behaviour of the system, flow at the steam generator outlet. Scale model testing of the steam generator outlet region. Hydraulic flow disturbances in the main steam system were measured using pressure and strain gauges, which made it possible to track individual pressure pulses propagating through the main steam system. Analyses showed that the pressure pulses causing the vibration originated from the vicinity of the steam generator outlet. By using computer codes for network fluid flow analyses the pressure pulses found in the measurement traces could be generated in calculations. Careful studies of the flow at the steam generator outlet region, using model testing in a 1:3 scale model as well as transient 3D CFD calculations, gave clear indications that flow separation occurred at the steam generator outlet nozzle and at the first bend. Finally, by substituting the outlet nozzle for a different design with a multi-port nozzle, the steam line vibration problem has been solved. (authors)

  18. Selective tumor cell death induced by irradiated riboflavin through recognizing DNA G-T mismatch.

    Science.gov (United States)

    Yuan, Yi; Zhao, Yongyun; Chen, Lianqi; Wu, Jiasi; Chen, Gangyi; Li, Sheng; Zou, Jiawei; Chen, Rong; Wang, Jian; Jiang, Fan; Tang, Zhuo

    2017-09-06

    Riboflavin (vitamin B2) has been thought to be a promising antitumoral agent in photodynamic therapy, though the further application of the method was limited by the unclear molecular mechanism. Our work reveals that riboflavin was able to recognize G-T mismatch specifically and induce single-strand breaks in duplex DNA targets efficiently under irradiation. In the presence of riboflavin, the photo-irradiation could induce the death of tumor cells that are defective in mismatch repair system selectively, highlighting the G-T mismatch as potential drug target for tumor cells. Moreover, riboflavin is a promising leading compound for further drug design due to its inherent specific recognition of the G-T mismatch. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  19. Microsatellite D21D210 (GT-12) allele frequencies in sporadic Alzheimer's disease

    International Nuclear Information System (INIS)

    Lannfelt, L.; Lilius, L.; Viitanen, M.; Winblad, B.; Basun, H.; Houlden, H.; Rossor, M.; Hardy, J.

    1995-01-01

    Four disease-causing mutations have so far been described in the amyloid precursor protein gene on chromosome 21 in familial early-onset Alzheimer's disease. Linkage analysis with a fourteen-allele microsatellite at D21S210 named GT-12 has proven useful in the elucidation of amyloid presursor protein gene involvement in Alzheimer's disease families, as it is closely linked to the gene. Most cases of Alzheimer's disease are thought to be sporadic and not familial. However, evidence from earlier studies suggests an important genetic contribution also in sporadic cases, where gene-environment interaction may contribute to the disease. We have determined frequencies of the GT-12 alleles in 78 Swedish and 49 British sporadic Alzheimer's disease cases and 104 healthy elderly control subjects, to investigate if the disease associates with a particular genotype in GT-12. However, no differences in allele frequencies were observed between any of the groups. (au) (26 refs.)

  20. An Improved Steam Injection Model with the Consideration of Steam Override

    OpenAIRE

    He , Congge; Mu , Longxin; Fan , Zifei; Xu , Anzhu; Zeng , Baoquan; Ji , Zhongyuan; Han , Haishui

    2017-01-01

    International audience; The great difference in density between steam and liquid during wet steam injection always results in steam override, that is, steam gathers on the top of the pay zone. In this article, the equation for steam override coefficient was firstly established based on van Lookeren’s steam override theory and then radius of steam zone and hot fluid zone were derived according to a more realistic temperature distribution and an energy balance in the pay zone. On this basis, th...

  1. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1982-04-01

    The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1980. Tube defects occurred at 38% of the 97 reactors surveyed. This is a marginal improvement over 1979 when defects occurred at 41% of the reactors. The number of failed tubes was also lower, 0.14% of the tubes in service in 1980 compared with 0.20% of those in service in 1979. Analysis of the causes of these failures indicates that stress corrosion cracking was the leading failure mechanism. Reactors that used all-volatile treatment of secondary water, with or without full-flow condensate demineralization since start-up showed the lowest incidence of corrosion-related defects

  2. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1983-08-01

    A review of the performance of steam generator tubes in 110 water-cooled nuclear power reactors showed that tubes were plugged at 46 (42 percent) of the reactors. The number of tubes removed from service increased from 1900 (0.14 percent) in 1980 to 4692 (0.30 percent) in 1981. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that used all-volatile treatment since start-up. At one reactor a large number of degraded tubes were repaired by sleeving which is expected to become an important method of tube repair in the future

  3. Erosion corrosion in wet steam

    International Nuclear Information System (INIS)

    Tavast, J.

    1988-03-01

    The effect of different remedies against erosion corrosion in wet steam has been studied in Barsebaeck 1. Accessible steam systems were inspected in 1984, 1985 and 1986. The effect of hydrogen peroxide injection of the transport of corrosion products in the condensate and feed water systems has also been followed through chemical analyses. The most important results of the project are: - Low alloy chromium steels with a chromium content of 1-2% have shown excellent resistance to erosion corrosion in wet steam. - A thermally sprayed coating has shown good resistance to erosion corrosion in wet steam. In a few areas with restricted accessibility minor attacks have been found. A thermally sprayed aluminium oxide coating has given poor results. - Large areas in the moisture separator/reheater and in steam extraction no. 3 have been passivated by injection of 20 ppb hydrogen peroxide to the high pressure steam. In other inspected systems no significant effect was found. Measurements of the wall thickness in steam extraction no. 3 showed a reduced rate of attack. - The injection of 20 ppb hydrogen peroxide has not resulted in any significant reduction of the iron level result is contrary to that of earlier tests. An increase to 40 ppb resulted in a slight decrease of the iron level. - None of the feared disadvantages with hydrogen peroxide injection has been observed. The chromium and cobalt levels did not increase during the injection. Neither did the lifetime of the precoat condensate filters decrease. (author)

  4. LU60645GT and MA132843GT Catalogues of Lunar and Martian Impact Craters Developed Using a Crater Shape-based Interpolation Crater Detection Algorithm for Topography Data

    Science.gov (United States)

    Salamuniccar, Goran; Loncaric, Sven; Mazarico, Erwan Matias

    2012-01-01

    For Mars, 57,633 craters from the manually assembled catalogues and 72,668 additional craters identified using several crater detection algorithms (CDAs) have been merged into the MA130301GT catalogue. By contrast, for the Moon the most complete previous catalogue contains only 14,923 craters. Two recent missions provided higher-quality digital elevation maps (DEMs): SELENE (in 1/16° resolution) and Lunar Reconnaissance Orbiter (we used up to 1/512°). This was the main motivation for work on the new Crater Shape-based interpolation module, which improves previous CDA as follows: (1) it decreases the number of false-detections for the required number of true detections; (2) it improves detection capabilities for very small craters; and (3) it provides more accurate automated measurements of craters' properties. The results are: (1) LU60645GT, which is currently the most complete (up to D>=8 km) catalogue of Lunar craters; and (2) MA132843GT catalogue of Martian craters complete up to D>=2 km, which is the extension of the previous MA130301GT catalogue. As previously achieved for Mars, LU60645GT provides all properties that were provided by the previous Lunar catalogues, plus: (1) correlation between morphological descriptors from used catalogues; (2) correlation between manually assigned attributes and automated measurements; (3) average errors and their standard deviations for manually and automatically assigned attributes such as position coordinates, diameter, depth/diameter ratio, etc; and (4) a review of positional accuracy of used datasets. Additionally, surface dating could potentially be improved with the exhaustiveness of this new catalogue. The accompanying results are: (1) the possibility of comparing a large number of Lunar and Martian craters, of e.g. depth/diameter ratio and 2D profiles; (2) utilisation of a method for re-projection of datasets and catalogues, which is very useful for craters that are very close to poles; and (3) the extension of the

  5. CANDU steam generator life management

    International Nuclear Information System (INIS)

    Tapping, R.L.; Nickerson, J.; Spekkens, P.; Maruska, C.

    1998-01-01

    Steam generators are a critical component of a nuclear power reactor, and can contribute significantly to station unavailability, as has been amply demonstrated in Pressurized Water Reactors (PWRs). CANDU steam generators are not immune to steam generator degradation, and the variety of CANDU steam generator designs and tube materials has led to some unexpected challenges. However, aggressive remedial actions, and careful proactive maintenance activities, have led to a decrease in steam generator-related station unavailability of Canadian CANDUs. AECL and the CANDU utilities have defined programs that will enable existing or new steam generators to operate effectively for 40 years. Research and development work covers corrosion and mechanical degradation of tube bundles and internals, chemistry, thermalhydraulics, fouling, inspection and cleaning, as well as provision for specially tool development for specific problem solving. A major driving force is development of CANDU-specific fitness-for-service guidelines, including appropriate inspection and monitoring technology to measure steam generator condition. Longer-range work focuses on development of intelligent on-line monitoring for the feedwater system and steam generator. New designs have reduced risk of corrosion and fouling, are more easily inspected and cleaned, and are less susceptible to mechanical damage. The Canadian CANDU utilities have developed programs for remedial actions to combat degradation of performance (Gentilly-2, Point Lepreau, Bruce A/B, Pickering A/B), and have developed strategic plans to ensure that good future operation is ensured. The research and development program, as well as operating experience, has identified where improvements in operating practices and/or designs can be made in order to ensure steam generator design life at an acceptable capacity factory. (author)

  6. Performance and environment as objectives in multi-criterion optimization of steam injected gas turbine cycles

    International Nuclear Information System (INIS)

    Kayadelen, Hasan Kayhan; Ust, Yasin

    2014-01-01

    Rapidly growing demand for gas turbines promotes research on their performance improvement and reducing their exhaust pollutants. Even small increments in net power or thermal efficiency and small changes in pollutant emissions have become significant concerns for both new designs and cycle modifications. To fulfill these requirements an accurate performance evaluation method which enables to see the effects on the exhaust gas composition is an important necessity. To fill this gap, a thermo-ecologic performance evaluation approach for gas turbine cycles with chemical equilibrium approximation which enables performance and environmental aspects to be considered simultaneously, is presented in this work. Steam injection is an effective modification to boost power and limit NO x emissions for gas turbine systems. Steam injection also increases thermal efficiency so less fuel is burnt to maintain the same power output. Because of its performance related and environmental advantages, presented approach is applied on the steam injected gas turbine cycle and a precise multi-criterion optimization is carried out for varying steam injection, as well as equivalence and pressure ratios. Irreversibilities and pressure losses are also considered. Effects of each parameter on the net work and thermal efficiency as well as non-equilibrium NO x and CO emissions are demonstrated. Precision improvement of the presented thermo-ecological model is shown and two main concerns; constant turbine inlet condition for higher net work output and constant net work output condition for lower fuel consumption are compared. - Highlights: • A thermodynamically precise performance estimation tool for GT cycles is presented. • STIG application is provided to show its flexibility for any GT cycle and diluents. • Constant TIT and net work output conditions have been compared and discussed. • The model provides results to evaluate economic and environmental aspects together. • It provides a

  7. Advanced technologies on steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Sakata, Kaoru; Nakamura, Yuuki [Mitsubishi Heavy Industry Co., Takasago (Japan); Nakamori, Nobuo; Mizutani, Toshiyuki; Uwagawa, Seiichi; Saito, Itaru [Mitsubishi Heavy Industry Co., Kobe (Japan); Matsuoka, Tsuyoshi [Mitsubishi Heavy Industry Co., Yokohama (Japan)

    1997-12-31

    The thermal-hydraulic tests for a horizontal steam generator of a next-generation PWR (New PWR-21) were performed. The purpose of these tests is to understand the thermal-hydraulic behavior in the secondary side of horizontal steam generator during the plant normal operation. A test was carried out with cross section slice model simulated the straight tube region. In this paper, the results of the test is reported, and the effect of the horizontal steam generator internals on the thermalhydraulic behavior of the secondary side and the circulation characteristics of the secondary side are discussed. (orig.). 3 refs.

  8. Steam reformer with catalytic combustor

    Science.gov (United States)

    Voecks, Gerald E. (Inventor)

    1990-01-01

    A steam reformer is disclosed having an annular steam reforming catalyst bed formed by concentric cylinders and having a catalytic combustor located at the center of the innermost cylinder. Fuel is fed into the interior of the catalytic combustor and air is directed at the top of the combustor, creating a catalytic reaction which provides sufficient heat so as to maintain the catalytic reaction in the steam reforming catalyst bed. Alternatively, air is fed into the interior of the catalytic combustor and a fuel mixture is directed at the top. The catalytic combustor provides enhanced radiant and convective heat transfer to the reformer catalyst bed.

  9. Advanced technologies on steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Sakata, Kaoru; Nakamura, Yuuki [Mitsubishi Heavy Industry Co., Takasago (Japan); Nakamori, Nobuo; Mizutani, Toshiyuki; Uwagawa, Seiichi; Saito, Itaru [Mitsubishi Heavy Industry Co., Kobe (Japan); Matsuoka, Tsuyoshi [Mitsubishi Heavy Industry Co., Yokohama (Japan)

    1998-12-31

    The thermal-hydraulic tests for a horizontal steam generator of a next-generation PWR (New PWR-21) were performed. The purpose of these tests is to understand the thermal-hydraulic behavior in the secondary side of horizontal steam generator during the plant normal operation. A test was carried out with cross section slice model simulated the straight tube region. In this paper, the results of the test is reported, and the effect of the horizontal steam generator internals on the thermalhydraulic behavior of the secondary side and the circulation characteristics of the secondary side are discussed. (orig.). 3 refs.

  10. Wet-steam erosion of steam turbine disks and shafts

    International Nuclear Information System (INIS)

    Averkina, N. V.; Zheleznyak, I. V.; Kachuriner, Yu. Ya.; Nosovitskii, I. A.; Orlik, V. G.; Shishkin, V. I.

    2011-01-01

    A study of wet-steam erosion of the disks and the rotor bosses or housings of turbines in thermal and nuclear power plants shows that the rate of wear does not depend on the diagrammed degree of moisture, but is determined by moisture condensing on the surfaces of the diaphragms and steam inlet components. Renovating the diaphragm seals as an assembly with condensate removal provides a manifold reduction in the erosion.

  11. Transient analysis of a U-tube natural circulation steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Gaikwad, A J; Kumar, Rajesh; Bhadra, Anu; Chakraborty, G; Venkat Raj, V [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    A computer code has been developed, for transient thermal-hydraulic analysis of proposed 500 MWe PHWR steam generator. The transient behaviour of a nuclear power plant is very much dependent on the steam generator performance, as it provides a thermal linkage between the primary and secondary systems. Study of dynamics of steam generator is essential for over all power plant dynamics as well as design of control systems for steam generator. A mathematical model has been developed for the simulation of thermal-hydraulic phenomena in a U tube natural circulation steam generator. Fluid model is based on one dimensional, nonlinear, single fluid conservation equations of mass, momentum, energy and equation of state. This model includes coupled two phase flow heat transfer and natural circulation. The model accounts for both compressibility and thermal expansion effects. The process simulation and results obtained for transients such as step change in load and total loss of feed water are presented. (author). 5 refs., 7 figs.

  12. SNR-steam generator design with respect to large sodium water reactions

    International Nuclear Information System (INIS)

    Jong, J.J. de; Kellner, A.; Florie, C.J.L.

    1984-01-01

    This paper deals with the experiences gained during the licensing procedure for the steam generators for the SNR 300 LMFBR regarding large sodium-water reactions. A description is given of the different calculations executed to investigate the effects of large leaks on the 85 MW helical coiled and straight tube steam generators. The investigations on the helical coiled steam generators are divided in the formulations of fluid behaviour, dynamic force calculations, dynamic response calculation and finally stress analyses. Several results are shown. The investigations on the straight tube steam generators are performed using models describing fluid-structure interaction, coupled with stress analyses. Several results are presented. A description is given of the problems and necessary construction changes during the licensing process. Advises are given for future analyses and design concepts for second generation commercial size LMFBR steam generators with respect to large leaks; based on the experience, gained with SNR 300, and using some new calculations for SNR 2. (author)

  13. In situ analysis of chemical components induced by steaming between fresh ginseng, steamed ginseng, and red ginseng

    Directory of Open Access Journals (Sweden)

    Gyo In

    2017-07-01

    Conclusion: This study elucidates the dynamic changes in the chemical components of P. ginseng when the steaming process was induced. These results are thought to be helpful for quality control and standardization of herbal drugs using P. ginseng and they also provide a scientific basis for pharmacological research of processed ginseng (Red ginseng.

  14. Steam consumption minimization model in a multiple evaporation effect in a sugar plant

    International Nuclear Information System (INIS)

    Villada, Fernando; Valencia, Jaime A; Moreno, German; Murillo, J. Joaquin

    1992-01-01

    In this work, a mathematical model to minimize the steam consumption in a multiple effect evaporation system is shown. The model is based in the dynamic programming technique and the results are tested in a Colombian sugar mill

  15. Regulation of ageing steam generators

    International Nuclear Information System (INIS)

    Jarman, B.L.; Grant, I.M.; Garg, R.

    1998-01-01

    Recent years have seen leaks and shutdowns of Canadian CANDU plants due to steam generator tube degradation by mechanisms including stress corrosion cracking, fretting and pitting. Failure of a single steam generator tube, or even a few tubes, would not be a serious safety related event in a CANDU reactor. The leakage from a ruptured tube is within the makeup capacity of the primary heat transport system, so that as long as the operator takes the correct actions, the off-site consequences will be negligible. However, assurance that no tubes deteriorate to the point where their integrity could be seriously breached as result of potential accidents, and that any leakage caused by such an accident will be small enough to be inconsequential, can only be obtained through detailed monitoring and management of steam generator condition. This paper presents the AECB's current approach and future regulatory directions regarding ageing steam generators. (author)

  16. Model of reverse steam generator

    International Nuclear Information System (INIS)

    Malasek, V.; Manek, O.; Masek, V.; Riman, J.

    1987-01-01

    The claim of Czechoslovak discovery no. 239272 is a model designed for the verification of the properties of a reverse steam generator during the penetration of water, steam-water mixture or steam into liquid metal flowing inside the heat exchange tubes. The design may primarily be used for steam generators with a built-in inter-tube structure. The model is provided with several injection devices configured in different heat exchange tubes, spaced at different distances along the model axis. The design consists in that between the pressure and the circumferential casings there are transverse partitions and that in one chamber consisting of the circumferential casings, pressure casing and two adjoining partitions there is only one passage of the injection device through the inter-tube space. (Z.M.). 1 fig

  17. Steam generator thermal-hydraulics

    International Nuclear Information System (INIS)

    Inch, W.W.; Scott, D.A.; Carver, M.B.

    1980-01-01

    This paper discusses a code for detailed numerical modelling of steam generator thermal-hydraulics, and describes related experimental programs designed to promote in-depth understanding of three-dimensional two-phase flow. (auth)

  18. Detection of non-ΔGT NCF-1 mutations in chronic granulomatous disease

    DEFF Research Database (Denmark)

    Jakobsen, Marianne Antonius; Pedersen, Svend Stenvang; Barington, Torben

    2009-01-01

    to have mutations in NCF-1 encoding p47-phox, which is part of the cytosolic component of NADPH oxidase. More than 94% of these patients share the same mutation, a 2 bp GT deletion in the GTGT dinucleotide repeat in the start of exon 2. The presence of two pseudogenes more than 98% homologous...

  19. Step-parent adoption gone wrong: GT v CT [2015] 3 ALL SA 631 (GJ ...

    African Journals Online (AJOL)

    Because of the immense impact on a child, the rescission of an adoption order has to be handled with kid gloves. In GT v CT [2015] 3 ALL SA 631 (GJ) two children had been legally adopted by their stepfather while the Child Care Act was in operation. After the implementation of the Children's Act 38 of 2005, however, ...

  20. Colletotrichine A, a new sesquiterpenoid from Colletotrichum gloeosporioides GT-7, a fungal endophyte of Uncaria rhynchophylla.

    Science.gov (United States)

    Chen, Xiao-Wei; Yang, Zhong-Duo; Sun, Jian-Hui; Song, Tong-Tong; Zhu, Bao-Ying; Zhao, Jun-Wen

    2018-04-01

    One new compound, Colletotrichine A (1), was produced by the fungal Colletotrichum gloeosporioides GT-7. The structure was established by 1D and 2D NMR spectra. Monoamine oxidase (MAO) and acetylcholinesterase (AChE) inhibitory activity of 1 was also evaluated. Compound 1 showed AChE-inhibiting activity with IC 50 value of 28 μg/mL.

  1. Comparison of Yamax pedometer and GT3X accelerometer steps in a free-living sample

    Science.gov (United States)

    Our objective was to compare steps detected by the Yamax pedometer (PEDO) versus the GT3X accelerometer (ACCEL) in free-living adults. Daily PEDO and ACCEL steps were collected from a sample of 23 overweight and obese participants (18 females; mean +/- sd: age = 52.6 +/- 8.4 yr.; body mass index = 3...

  2. French steam generator design developments

    International Nuclear Information System (INIS)

    Ginier, R.; Campan, J.L.; Pontier, M.; Leridon, A.; Remond, A.; Castello, G.; Holcblat, A.; Paurobally, H.

    1986-01-01

    From the outset of the French nuclear power program, a significant R and D effort has been invested in improvement of the design and operation of Pressurized Water Reactors including a special committment to improving steam generators. The steam generator enhancement program has spawned a wide variety of specific R and D resources, e.g., low temperature hydraulic models for investigation of areas with single-phase flow, and freon-filled models for simulation of areas of steam generators experiencing two-phase flow (tube bundles and moisture separators). For the moisture separators, a large scale research program using freon-filled models and highly sophisticated instrumentation was used. Tests at reactor sites during startup of both 900 MWe and 1300 MWe have been used to validate the assumptions made on the basis of loop tests. These tests also demonstrated the validity of using freon to simulate two-phase flow conditions. The wealth of knowledge accumulated by the steam generator R and D program has been used to develop a new design of steam generators for the N4 plants. The current R and D effort is aimed at qualifying the N4 steam generator model and developing more comprehensive models. One prong of the R and D effort is the Megeve program. Megeve is a 25 MW steam generator which simulates operating conditions of the N4 model. The other prong is Clotaire, a freon-filled steam generator model which will be used to qualify thermal/hydraulic design codes used for multidimensional calculations for design of tube bundles

  3. Research program plan: steam generators

    International Nuclear Information System (INIS)

    Muscara, J.; Serpan, C.Z. Jr.

    1985-07-01

    This document presents a plan for research in Steam Generators to be performed by the Materials Engineering Branch, MEBR, Division of Engineering Technology, (EDET), Office of Nuclear Regulatory Research. It is one of four plans describing the ongoing research in the corresponding areas of MEBR activity. In order to answer the questions posed, the Steam Generator Program has been organized with the three elements of non-destructive examination; mechanical integrity testing; and corrosion, cleaning and decontamination

  4. Physical and statistical models for steam generator clogging diagnosis

    CERN Document Server

    Girard, Sylvain

    2014-01-01

    Clogging of steam generators in nuclear power plants is a highly sensitive issue in terms of performance and safety and this book proposes a completely novel methodology for diagnosing this phenomenon. It demonstrates real-life industrial applications of this approach to French steam generators and applies the approach to operational data gathered from French nuclear power plants. The book presents a detailed review of in situ diagnosis techniques and assesses existing methodologies for clogging diagnosis, whilst examining their limitations. It also addresses numerical modelling of the dynamic

  5. Steam blowdown experiments with the condensation pool test rig

    International Nuclear Information System (INIS)

    Purhonen, H.; Puustinen, M.; Laine, J.; Raesaenen, A.; Kyrki-Rajamaeki, R.; Vihavainen, J.

    2005-01-01

    During a possible loss-of-coolant accident (Local) a large amount of non-condensable (nitrogen) and condensable (steam) gas is blown from the upper drywell of the containment to the condensation pool through the blowdown pipes at the boiling water reactors (BWRs). The wet well pool serves as the major heat sink for condensation of steam. The blowdown causes both dynamic and structural loads to the condensation pool. There might also be a risk that the gas discharging to the pool could push its way to the emergency core cooling systems (ECCS) and undermine their performance. (author)

  6. Mathematical modelling of steam generator and design of temperature regulator

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanovic, S.S. [EE Institute Nikola Tesla, Belgrade (Yugoslavia)

    1999-07-01

    The paper considers mathematical modelling of once-through power station boiler and numerical algorithm for simulation of the model. Fast and numerically stable algorithm based on the linearisation of model equations and on the simultaneous solving of differential and algebraic equations is proposed. The paper also presents the design of steam temperature regulator by using the method of projective controls. Dynamic behaviour of the system closed with optimal linear quadratic regulator is taken as the reference system. The desired proprieties of the reference system are retained and solutions for superheated steam temperature regulator are determined. (author)

  7. Investigation of brush seals for application in steam turbines

    International Nuclear Information System (INIS)

    Zorn, Peter

    2012-01-01

    Brush seals have high potential for efficiency increase compared to conventional labyrinth seals in steam turbines. Due to less experience in operation today there is a lot of scepticism with customers of steam turbine manufacturers. Therefore this thesis is investigating characteristics of this type of seal. Experiments and numerical models will be presented, which lead to better knowledge about leakages and influence of flow through seal onto dynamics of rotor in comparison to labyrinth seals. This thesis is increasing area of experience and one more positive reference.

  8. Options for Steam Generator Decommissioning

    International Nuclear Information System (INIS)

    Krause, Gregor; Amcoff, Bjoern; Robinson, Joe

    2016-01-01

    Selecting the best option for decommissioning steam generators is a key consideration in preparing for decommissioning PWR nuclear power plants. Steam Generators represent a discrete waste stream of large, complex items that can lend themselves to a variety of options for handling, treatment, recycling and disposal. Studsvik has significant experience in processing full size Steam Generators at its metal recycling facility in Sweden, and this paper will introduce the Studsvik steam generator treatment concept and the results achieved to date across a number of projects. The paper will outline the important parameters needed at an early stage to assess options and to help consider the balance between off-site and on-site treatment solutions, and the role of prior decontamination techniques. The paper also outlines the use of feasibility studies and demonstration projects that have been used to help customers prepare for decommissioning. The paper discusses physical, radiological and operational history data, Pro and Contra factors for on- and off-site treatment, the role of chemical decontamination prior to treatment, planning for off-site shipments as well as Studsvik experience This paper has an original focus upon the coming challenges of steam generator decommissioning and potential external treatment capacity constraints in the medium term. It also focuses on the potential during operations or initial shut-down to develop robust plans for steam generator management. (authors)

  9. Analgesic effect of GT-0198, a structurally novel glycine transporter 2 inhibitor, in a mouse model of neuropathic pain

    Directory of Open Access Journals (Sweden)

    Yu Omori

    2015-03-01

    Full Text Available This study was conducted to identify the characteristic pharmacological features of GT-0198 that is phenoxymethylbenzamide derivatives. GT-0198 inhibited the function of glycine transporter 2 (GlyT2 in human GlyT2-expressing HEK293 cells and did not bind various major transporters or receptors of neurotransmitters in a competitive manner. Thus, GT-0198 is considered to be a comparatively selective GlyT2 inhibitor. Intravenous, oral, and intrathecal injections of GT-0198 decreased the pain-related response in a model of neuropathic pain with partial sciatic nerve ligation. This result suggests that GT-0198 has an analgesic effect. The analgesic effect of GT-0198 was abolished by the intrathecal injection of strychnine, a glycine receptor antagonist. Therefore, GT-0198 is considered to exhibit its analgesic effect via the activation of a glycine receptor by glycine following presynaptic GlyT2 inhibition in the spinal cord. In summary, GT-0198 is a structurally novel GlyT2 inhibitor bearing a phenoxymethylbenzamide moiety with in vivo efficacy in behavioral models of neuropathic pain.

  10. Structural Characterization of the Foliated-Layered Gabbro Transition in Wadi Tayin of the Samail Ophiolite, Oman; Oman Drilling Project Holes GT1A and GT2A

    Science.gov (United States)

    Deans, J. R.; Crispini, L.; Cheadle, M. J.; Harris, M.; Kelemen, P. B.; Teagle, D. A. H.; Matter, J. M.; Takazawa, E.; Coggon, J. A.

    2017-12-01

    Oman Drilling Project Holes GT1A and GT2A were drilled into the Wadi Tayin massif, Samail ophiolite and both recovered ca. 400 m of continuous core through a section of the layered gabbros and the foliated-layered gabbro transition. Hole GT1A is cut by a discrete fault system including localized thin ultracataclastic fault zones. Hole GT2A is cut by a wider zone of brittle deformation and incipient brecciation. Here we report the structural history of the gabbros reflecting formation at the ridge to later obduction. Magmatic and high temperature history- 1) Both cores exhibit a pervasive, commonly well-defined magmatic foliation delineated by plagioclase, olivine and in places clinopyroxene. Minor magmatic deformation is present. 2) The dip of the magmatic foliation varies cyclically, gradually changing dip by 30o from gentle to moderate over a 50 m wavelength. 3) Layering is present throughout both cores, is defined by changes in mode and grain size ranging in thickness from 2 cm to 3 m and is commonly sub-parallel to the foliation. 4) There are no high temperature crystal-plastic shear zones in the core. Key observations include: no simple, systematic shallowing of dip with depth across the foliated-layered gabbro transition and layering is continuous across this transition. Cyclic variation of magmatic foliation dip most likely reflects the process of plate separation at the ridge axis. Near-axis faulting- i) On or near-axis structures consist of epidote-amphibole bearing hydraulic breccias and some zones of intense cataclasis with intensely deformed epidote and seams of clay and chlorite accompanied by syntectonic alteration of the wall rock. Early veins are filled with amphibole, chlorite, epidote, and anhydrite. ii) The deformation ranges from brittle-ductile, causing local deflection of the magmatic foliation, to brittle offset of the foliation and core and mantle structures in anhydrite veins. iii) The prevalent sense of shear is normal and slickenfibers

  11. Forced circulation type steam generator simulation code: HT4

    International Nuclear Information System (INIS)

    Okamoto, Masaharu; Tadokoro, Yoshihiro

    1982-08-01

    The purpose of this code is a understanding of dynamic characteristics of the steam generator, which is a component of High-temperature Heat Transfer Components Test Unit. This unit is a number 4th test section of Helium Engineering Demonstration Loop (HENDEL). Features of this report are as follows, modeling of the steam generator, a basic relationship for the continuity equation, numerical analysis techniques of a non-linear simultaneous equation and computer graphics output techniques. Forced circulation type steam generator with strait tubes and horizontal cut baffles, applied in this code, have be designed at the Over All System Design of the VHTRex. The code is for use with JAERI's digital computer FACOM M200. About 1.5 sec required for each time step reiteration, then about 40 sec cpu time required for a standard problem. (author)

  12. Steam CFD simulation of injection in suppression pool

    International Nuclear Information System (INIS)

    Naveen Samad, A.M.; Ghosh, Sumana

    2015-01-01

    Boiling water reactor (BWR) is one of the common types of electricity generating nuclear reactor. Suppression pool system is a major component of the BWR which has to be designed efficiently for the safe operations. During some accidents like Loss of Coolant Accident (LOCA) large amount of steam are injected to the pressure suppression system resulting in increase in temperature of the pool and thereby increasing the pressure. The present work discuss about the Computational Fluid Dynamics (CFD) simulation of steam injected to the wet well of BWR through the blow down pipes and there by investigating the hydrodynamic and thermal characteristics of the system. The simulations were carried out for three different steam injection velocities. The numerical simulations were performed with ANSYS FLUENT using multiphase 3D Volume of Fluid (VOF) model and k-ε model was adopted for modelling turbulence flow. (author)

  13. Lower head integrity under steam explosion loads

    Energy Technology Data Exchange (ETDEWEB)

    Theofanous, T.G.; Yuen, W.W.; Angelini, S.; Freeman, K.; Chen, X.; Salmassi, T. [Center for Risk Studies and Safety, Univ. of California, Santa Barbara, CA (United States); Sienicki, J.J.

    1998-01-01

    Lower head integrity under steam explosion loads in an AP600-like reactor design is considered. The assessment is the second part of an evaluation of the in-vessel retention idea as a severe accident management concept, the first part (DOE/ID-10460) dealing with thermal loads. The assessment is conducted in terms of the Risk Oriented Accident Analysis Methodology (ROAAM), and includes the comprehensive evaluation of all relevant severe accident scenarios, melt conditions and timing of release from the core region, fully 3D mixing and explosion wave dynamics, and lower head fragility under local, dynamic loading. All of these factors and brought together in a ROAAM Probabilistic Framework to evaluate failure likelihood. The conclusion is that failure is `physically unreasonable`. (author)

  14. Solution of multiple circuits of steam cycle HTR system

    International Nuclear Information System (INIS)

    Li, Fu; Wang, Dengying; Hao, Chen; Zheng, Yanhua

    2014-01-01

    In order to analyze the dynamic operation performance and safety characteristics of the steam cycle high temperature gas cooled reactor (HTR) systems, it is necessary to find the solution of the whole HTR systems with all coupled circuits, including the primary circuit, the secondary circuit, and the residual heat removal system (RHRS). Considering that those circuits have their own individual fluidity and characteristics, some existing code packages for independent circuits themselves have been developed, for example THEMRIX and TINTE code for the primary circuit of the pebble bed reactor, BLAST for once through steam generator. To solve the coupled steam cycle HTR systems, a feasible way is to develop coupling method to integrate these independent code packages. This paper presents several coupling methods, e.g. the equivalent component method between the primary circuit and steam generator which reflect the close coupling relationship, the overlapping domain decomposition method between the primary circuit and the passive RHRS which reflects the loose coupling relationship. Through this way, the whole steam cycle HTR system with multiple circuits can be easily and efficiently solved by integration of several existing code packages. Based on this methodology, a code package TINTE–BLAST–RHRS was developed. Using this code package, some operation performance of HTR–PM was analyzed, such as the start-up process of the plant, and the depressurized loss of forced cooling accident when different number of residual heat removal trains is operated

  15. Overview of Hole GT2A: Drilling middle gabbro in Wadi Tayin massif, Oman ophiolite

    Science.gov (United States)

    Takazawa, E.; Kelemen, P. B.; Teagle, D. A. H.; Coggon, J. A.; Harris, M.; Matter, J. M.; Michibayashi, K.

    2017-12-01

    Hole GT2A (UTM: 40Q 655960.7E / 2529193.5N) was drilled by the Oman Drilling Project (OmDP) into Wadi Gideah of Wadi Tayin massif in the Samail ophiolite, Oman. OmDP is an international collaboration supported by the International Continental Scientific Drilling Program, the Deep Carbon Observatory, NSF, IODP, JAMSTEC, and the European, Japanese, German and Swiss Science Foundations, with in-kind support in Oman from the Ministry of Regional Municipalities and Water Resources, Public Authority of Mining, Sultan Qaboos University, and the German University of Technology. Hole GT2A was diamond cored in 25 Dec 2016 to 18 Jan 2017 to a total depth of 406.77 m. The outer surfaces of the cores were imaged and described on site before being curated, boxed and shipped to the IODP drill ship Chikyu, where they underwent comprehensive visual and instrumental analysis. 33 shipboard scientists were divided into six teams (Igneous, Alteration, Structural, Geochem, Physical Properties, Paleomag) to describe and analyze the cores. Hole GT2A drilled through the transition between foliated and layered gabbro. The transition zone occurs between 50 and 150 m curation corrected depth (CCD). The top 50 m of Hole GT2A is foliated gabbro whereas the bottom 250 m consists of layered gabbro. Brittle fracture is observed throughout the core. Intensity of alteration vein decreases from the top to the bottom of the hole. On the basis of changes in grain size and/or modal abundance and/or appearance/disappearance of igneous primary mineral(s) five lithological units are defined in Hole GT2A (Unit I to V). The uppermost part of Hole GT2A (Unit I) is dominated by fine-grained granular olivine gabbro intercalated with less dominant medium-grained granular olivine gabbro and rare coarse-grained varitextured gabbro. The lower part of the Hole (Units II, III and V) is dominated by medium-grained olivine gabbro, olivine melagabbro and olivine-bearing gabbro. Modally-graded rhythmic layering with

  16. Operating results of 220 MW SKODA saturated steam turbines

    International Nuclear Information System (INIS)

    Drahy, J.

    1992-01-01

    One of the steam turbines produced by the SKODA Works, the 220 MW steam turbine for saturated admission steam of a speed of 3000 r.p.m. is described; it is used in nuclear power plants with 400 MW PWR type reactors. 16 units of 8 turbines each have been in operation in the Jaslovske Bohunice and Dukovany power plants with the total period of operation of all machines exceeding 750,000 hours. The 220 MW steam turbine consists of a two-flow high-pressure section and of two identical two-flow low-pressure sections. The pressure of saturated steam at the inlet of the high-pressure section is 4.32 MPa (the corresponding temperature of the saturation limit being 255 degC) and during the expansion in the high-pressure section it drops to 0.6 MPa; steam moisture reaches 12%. In a separator and two-stage reheater using blend steam, the steam is freed of the moisture and is reheated to a temperature of 217 degC. Some operational problems are discussed, as are the loss of the material of the stator parts of the high-pressure section due to corrosion-erosion wear and corrosion-erosion wear of the guide wheels of the high-pressure section, and measures are presented carried out for the reduction of the corrosion-erosion effects of wet steam. One of the serious problems were the fatigue fractures of the blades of the 4th high-pressure stage, which appeared after 20 000 to 24 000 hours of operation in the dented tee-root. The guide wheels of the 4th stage were substituted by new guide wheels with uniform pitch of the channels and with increased number of guide blades. Also discussed are the dynamic behavior of the low-pressure section of the bridge structure, the operating reliability and the heat off-take for water heating of long-distance heating systems. (Z.S.) 9 figs

  17. An essential GT motif in the lamin A promoter mediates activation by CREB-binding protein

    International Nuclear Information System (INIS)

    Janaki Ramaiah, M.; Parnaik, Veena K.

    2006-01-01

    Lamin A is an important component of nuclear architecture in mammalian cells. Mutations in the human lamin A gene lead to highly degenerative disorders that affect specific tissues. In studies directed towards understanding the mode of regulation of the lamin A promoter, we have identified an essential GT motif at -55 position by reporter gene assays and mutational analysis. Binding of this sequence to Sp transcription factors has been observed in electrophoretic mobility shift assays and by chromatin immunoprecipitation studies. Further functional analysis by co-expression of recombinant proteins and ChIP assays has shown an important regulatory role for CREB-binding protein in promoter activation, which is mediated by the GT motif

  18. HTGR-GT primary coolant transient resulting from postulated turbine deblading

    International Nuclear Information System (INIS)

    Cadwallader, G.J.; Deremer, R.K.

    1980-11-01

    The turbomachine is located within the primary coolant system of a nuclear closed cycle gas turbine plant (HTGR-GT). The deblading of the turbine can cause a rapid pressure equilibration transient that generates significant loads on other components in the system. Prediction of and design for this transient are important aspects of assuring the safety of the HTGR-GT. This paper describes the adaptation and use of the RATSAM program to analyze the rapid fluid transient throughout the primary coolant system during a spectrum of turbine deblading events. Included are discussions of (1) specific modifications and improvements to the basic RATSAM program, which is also briefly described; (2) typical results showing the expansion wave moving upstream from the debladed turbine through the primary coolant system; and (3) the effect on the transient results of different plenum volumes, flow resistances, times to deblade, and geometries that can choke the flow

  19. Actual characteristics study on HTR-10GT coupling with direct gas turbine cycle

    International Nuclear Information System (INIS)

    Peng Xuechuang; Zhu Shutang; Wang Jie

    2005-01-01

    HTR-10GT is a testing project coupling the reactor HTR-10 with direct gas turbine cycle. Its thermal cycle can be taken as a closed, recuperated and inter-cooled Brayton cycle. The present study is focused on the thermal cycle performance of HTR-10GT under practical conditions of leakage, pressure losses, etc.. Through thermodynamic analysis, the expression of cycle efficiency for actual thermal cycle is derived. By establishing a physical model with friction loss and leakage, a set of governing equation are constructed based on some reasonable assumptions. The results of actual cycle efficiency have been calculated for different leakage amount at different locations while the effects of leakage under different power level have also been calculated and analyzed. (authors)

  20. DISTORSI KAPASITAS PERDAGANGAN INTER-REGIONAL IMT-GT Kasus Provinsi Terpilih di Sumatera Indonesia

    Directory of Open Access Journals (Sweden)

    Benito Rio Avianto

    2015-06-01

    Full Text Available The objective of the paper was to understand the impact of sub regional economic cooperation, known as the Indonesia-Malaysia-Thailand Growth Triangle (IMT-GT, on trade sector in Indonesia. The approach of research based on export macro information by provinces and commodities. The method used in the analytical framework was a fixed effect method. The regional study covered Nanggroe Aceh Darussalam, North Sumatera, West Sumatera, and Riau provinces, and the commodities involved CPO, coffee and rubber, with 1990-2008 data series. Based on pooled regression, there was a significant impact on export from the four provinces to Malaysia and Thailand for all based years. One might focus on commodity level that, in fact, CPO was the only one commodity that had a significant impact within the IMTGT region. In addition, Thai Bath and Malaysian Ringgit, with respect to GDP for both countries, had significant influenced on export, especially after the IMT-GT endorsed.

  1. Maintaining steam/condensate lines

    International Nuclear Information System (INIS)

    Russum, S.A.

    1992-01-01

    Steam and condensate systems must be maintained with the same diligence as the boiler itself. Unfortunately, they often are not. The water treatment program, critical to keeping the boiler at peak efficiency and optimizing operating life, should not stop with the boiler. The program must encompass the steam and condensate system as well. A properly maintained condensate system maximizes condensate recovery, which is a cost-free energy source. The fuel needed to turn the boiler feedwater into steam has already been provided. Returning the condensate allows a significant portion of that fuel cost to be recouped. Condensate has a high heat content. Condensate is a readily available, economical feedwater source. Properly treated, it is very pure. Condensate improves feedwater quality and reduces makeup water demand and pretreatment costs. Higher quality feedwater means more reliable boiler operation

  2. Steam generator operation and maintenance

    International Nuclear Information System (INIS)

    Lee, C.K.

    2004-01-01

    Corrosion of steam generator tube has resulted in the need for extensive repair and replacement of steam generators. Over the past two decades, steam generator problems in the United States were viewed to be one of the most significant contributor to lost generation in operating PWR plants. When the SGOG-I (Steam Generator Owners Groups) was formed in early 1977, denting was responsible for almost 90% of the tube plugging. By the end of 1982, this figure was reduced to less than 2%. During the existence of SGOG-II (from 1982 to 1986), IGA/SCC (lntergranular Attack/Stress Corrosion Cracking) in the tube sheet, primary side SCC, pitting, and fretting surfaced as the primary causes of tube degradation. Although significant process has been made with wastage and denting, the utilities experience shows that the percentage of reactors plugging tubes and the percentage of tubes being plugged each year has remained relatively constant. The diversity of the damage mechanisms means that no one solution is likely to resolve all problems. The task of maintaining steam generator integrity continues to be formidable and challenging. As the older problems were brought under control, many new problems emerged. SGOG-II (Steam Generator Owners Group program from 1982 to 1986) has focused on these problem areas such as tube stress corrosion cracking (SCC) and intergranular attack (IGA) in the open tube sheet crevice, primary side tube cracking, pitting in the lower span, and tube fretting in preheated section and anti-vibration bar (AVB) locations. Primary Water Stress Corrosion Cracking (PWSCC) in the tube to tubesheet roll transition has been a wide spread problem in the Recirculation Steam Generators (RSG) during this period. Although significant progress has been made in resolving this problem, considerable work still remains. One typical problem in the Once Through Steam Generator (OTSG) was the tube support plate broached hole fouling which affects the OTSG steam generating

  3. Water box for steam generator

    International Nuclear Information System (INIS)

    Lecomte, Robert; Viaud, Michel.

    1975-01-01

    This invention relates to a water box for connecting an assembly composed of a vertical steam generator and a vertical pump to the vessel of the nuclear reactor, the assembly forming the primary cooling system of a pressurised water reactor. This invention makes it easy to dismantle the pump on the water box without significant loss of water in the primary cooling system of the reactor and particularly without it being necessary to drain the water contained in the steam generator beforehand. It makes it possible to shorten the time required for dismantling the primary pump in order to service or repair it and makes dismantling safer in that the dismantling does not involve draining the steam generator and therefore the critical storage of a large amount of cooling water that has been in contact with the fuel assemblies of the nuclear reactor core [fr

  4. The Vitamin E Analog Gamma-Tocotrienol (GT3 and Statins Synergistically Up-Regulate Endothelial Thrombomodulin (TM

    Directory of Open Access Journals (Sweden)

    Rupak Pathak

    2016-11-01

    Full Text Available Statins; a class of routinely prescribed cholesterol-lowering drugs; inhibit 3-hydroxy-3-methylglutaryl-coenzymeA reductase (HMGCR and strongly induce endothelial thrombomodulin (TM; which is known to have anti-inflammatory; anti-coagulation; anti-oxidant; and radioprotective properties. However; high-dose toxicity limits the clinical use of statins. The vitamin E family member gamma-tocotrienol (GT3 also suppresses HMGCR activity and induces TM expression without causing significant adverse side effects; even at high concentrations. To investigate the synergistic effect of statins and GT3 on TM; a low dose of atorvastatin and GT3 was used to treat human primary endothelial cells. Protein-level TM expression was measured by flow cytometry. TM functional activity was determined by activated protein C (APC generation assay. Expression of Kruppel-like factor 2 (KLF2, one of the key transcription factors of TM, was measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR. TM expression increased in a dose-dependent manner after both atorvastatin and GT3 treatment. A combined treatment of a low-dose of atorvastatin and GT3 synergistically up-regulated TM expression and functional activity. Finally; atorvastatin and GT3 synergistically increased KLF2 expression. These findings suggest that combined treatment of statins with GT3 may provide significant health benefits in treating a number of pathophysiological conditions; including inflammatory and cardiovascular diseases.

  5. Predicting steam generator crevice chemistry

    International Nuclear Information System (INIS)

    Burton, G.; Strati, G.

    2006-01-01

    'Full text:' Corrosion of steam cycle components produces insoluble material, mostly iron oxides, that are transported to the steam generator (SG) via the feedwater and deposited on internal surfaces such as the tubes, tube support plates and the tubesheet. The build up of these corrosion products over time can lead to regions of restricted flow with water chemistry that may be significantly different, and potentially more corrosive to SG tube material, than the bulk steam generator water chemistry. The aim of the present work is to predict SG crevice chemistry using experimentation and modelling as part of AECL's overall strategy for steam generator life management. Hideout-return experiments are performed under CANDU steam generator conditions to assess the accumulation of impurities in hideout, and return from, model crevices. The results are used to validate the ChemSolv model that predicts steam generator crevice impurity concentrations, and high temperature pH, based on process parameters (e.g., heat flux, primary side temperature) and blowdown water chemistry. The model has been incorporated into ChemAND, AECL's system health monitoring software for chemistry monitoring, analysis and diagnostics that has been installed at two domestic and one international CANDU station. ChemAND provides the station chemists with the only method to predict SG crevice chemistry. In one recent application, the software has been used to evaluate the crevice chemistry based on the elevated, but balanced, SG bulk water impurity concentrations present during reactor startup, in order to reduce hold times. The present paper will describe recent hideout-return experiments that are used for the validation of the ChemSolv model, station experience using the software, and improvements to predict the crevice electrochemical potential that will permit station staff to ensure that the SG tubes are in the 'safe operating zone' predicted by Lu (AECL). (author)

  6. Nuclear reactor steam depressurization valve

    International Nuclear Information System (INIS)

    Moore, G.L.

    1991-01-01

    This patent describes improvement in a nuclear reactor plant, an improved steam depressurization valve positioned intermediate along a steam discharge pipe for controlling the venting of steam pressure from the reactor through the pipe. The improvement comprises: a housing including a domed cover forming a chamber and having a partition plate dividing the chamber into a fluid pressure activation compartment and a steam flow control compartment, the valve housing being provided with an inlet connection and an outlet connection in the steam flow control compartment, and a fluid duct in communication with a source of fluid pressure for operating the valve; a valve set mounted within the fluid flow control compartment comprising a cylindrical section surrounding the inlet connection with one end adjoining the connection and having a radially projecting flange at the other end with a contoured extended valve sealing flange provided with an annular valve sealing member, and a valve cylinder traversing the partition plate and reciprocally movable within an opening in the partition plate with one terminal and extending into the fluid pressure activation compartment and the other terminal end extending into the steam flow control compartment coaxially aligned with the valve seat surrounding the inlet connection, the valve cylinder being surrounded by two bellow fluid seals and provided with guides to inhibit lateral movement, an end of the valve cylinder extending into the fluid flow control compartment having a radially projecting flange substantially conterminous with the valve seat flange and having a contoured surface facing and complimentary to the contoured valve seating surface whereby the two contoured valve surfaces can meet in matching relationship, thus providing a pressure actuated reciprocatable valve member for making closing contact with the valve seat and withdrawing therefrom for opening fluid flow through the valve

  7. Design, Operation and Control Modelling of SOFC/GT Hybrid Systems

    OpenAIRE

    Stiller, Christoph

    2006-01-01

    This thesis focuses on modelling-based design, operation and control of solid oxide fuel cell (SOFC) and gas turbine (GT) hybrid systems. Fuel cells are a promising approach to high-efficiency power generation, as they directly convert chemical energy to electric work. High-temperature fuel cells such as the SOFC can be integrated in gas turbine processes, which further increases the electrical efficiency to values up to 70%. However, there are a number of obstacles for safe operation of such...

  8. Determination of stresses caused by fluctuation of acoustic load in the steam dryers of a BWR

    International Nuclear Information System (INIS)

    Centeno P, J.; Quezada G, S.; Prieto G, A.; Vazquez R, A.; Espinosa P, G.; Nunez C, A.

    2014-10-01

    The extended power up-rate (EPU) in a nuclear power plant cause various problems in BWR components also in the steam system. This due to increased steam flow generated in the reactor and is conveyed to the turbine by the four main steam lines (MSL). One of the most serious problems is the generation of acoustic pressure loads in the metal structure of the steam dryer which eventually leads to fatigue failure and even the appearance of cracks, and in turn it causes loose parts that are entrained by the steam and transported in the MSL. This problem is due to the fluctuation of load acoustics caused by the union of the safety or relief valves (SRV) with the MSL, spreading through these to reach the reactor pressure vessel (RPV) where the effect of resonance of the acoustic wave is amplified and impacts directly in the supporting structure of the steam dryer, skirt and the panels where the mixture liquid-steam is dried, by centrifugation effect and runoff of liquid water. Efforts in the steam dryer operating conditions of EPU for two cases will be analyzed in this work, the first is before the installation of Acoustic Side Branch (ASB), and in the second case we consider the installation of said ASB in the standpipes of SRV. The analysis was performed with numerical experiments on a platform for computational fluid dynamics with virtual geometries previously designed based on the actual components of the reactor and steam system. The model to study is delimited by the top of the RPV, the steam dryer and a section of each of the four MSL with ten standpipes of SRV. With the obtained data and considering the mechanical-structural properties of the steam dryer material, we can evaluate the mechanical resistance to impacts by acoustic pressure load and its possible deformation or cracking. (Author)

  9. Nuclear steam generator tubesheet shield

    International Nuclear Information System (INIS)

    Nickerson, J.H.D.; Ruhe, A.

    1982-01-01

    The invention involves improvements to a nuclear steam generator of the type in which a plurality of U-shaped tubes are connected at opposite ends to a tubesheet and extend between inlet and outlet chambers, with the steam generator including an integral preheater zone adjacent to the downflow legs of the U-shaped tubes. The improvement is a thermal shield disposed adjacent to an upper face of the tubesheet within the preheater zone, the shield including ductile cladding material applied directly to the upper face of the tubesheet, with the downflow legs of the U-shaped tubes extending through the cladding into the tubesheet

  10. Steam turbines for PWR stations

    International Nuclear Information System (INIS)

    Muscroft, J.

    1989-01-01

    The thermodynamic cycle requirements and mechanical design features applying to modern GEC 3000 rev/min steam turbines for pressurised water reactor power stations are reviewed. The most recent developments include machines of 630 MW and 985 MW output which are currently under construction. The importance of service experience with nuclear wet steam turbines associated with a variety of types of water cooled reactor and its relevance to the design of modern 3000 rev/min turbines for pressurised water reactor applications is emphasised. (author)

  11. Double wall steam generator tubing

    International Nuclear Information System (INIS)

    Padden, T.R.; Uber, C.F.

    1983-01-01

    Double-walled steam generator tubing for the steam generators of a liquid metal cooled fast breeder reactor prevents sliding between the surfaces due to a mechanical interlock. Forces resulting from differential thermal expansion between the outer tube and the inner tube are insufficient in magnitude to cause shearing of base metal. The interlock is formed by jointly drawing the tubing, with the inside wall of the outer tube being already formed with grooves. The drawing causes the outer wall of the inner tube to form corrugations locking with the grooves. (author)

  12. Steam reforming of light oxygenates

    DEFF Research Database (Denmark)

    Trane-Restrup, Rasmus; Resasco, Daniel E; Jensen, Anker Degn

    2013-01-01

    Steam reforming (SR) of ethanol, acetic acid, acetone, acetol, 1-propanol, and propanal has been investigated over Ni/MgAl2O4 at temperatures between 400 and 700 degrees C and at a steam-to-carbon-ratio (S/C) of 6. The yield of H-2 and conversion increased with temperature, while the yield of by-...... of CH4. Significant deactivation of the catalyst was observed for all of the compounds and was mainly due to carbon formation. The carbon formation was highest for alcohols due to a high formation of olefins, which are potent coke precursors....

  13. Power unit with GT-MHR reactor plant for electricity production and district heating

    International Nuclear Information System (INIS)

    Kiryushin, A.L.; Kodochigov, N.G.; Kuzavkov, N.G.; Golovko, V.F.

    2000-01-01

    Modular helium reactor with the gas turbine (GT-MHR) is a perspective power reactor plant for the next century. The project reactor is based on experience of operation more than 50 gas-cooled reactors on carbon dioxide and helium, and also on subsequent achievements in the field of realization direct gas turbine Brayton cycle. To the beginning of 90 years, achievements in technology of gas turbines, highly effective recuperators and magnetic bearings made it possible to start development of the reactor plant project combining a safe modular gas cooled reactor and a power conversion system, realizing the highly effective Brayton cycle. The conceptual project of the commercial GT-MHR reactor plant fulfilled in 1997 by joint efforts of international firms, combines a safe modular reactor with an annular active core of prismatic fuel blocks and a power conversion system with direct gas turbine cycle. The efficiency of GT-MHR gas turbine cycle at level of about 48% makes it competitive in the electricity production market in comparison with any fossil or nuclear power stations

  14. Microsatellite D21D210 (GT-12) allele frequencies in sporadic Alzheimer`s disease

    Energy Technology Data Exchange (ETDEWEB)

    Lannfelt, L; Lilius, L; Viitanen, M; Winblad, B; Basun, H [Huddinge Hospital, Karolinska Institute, Dept. of Geriatric Medicine, (Sweden); Houlden, H; Rossor, M [St. Mary` s Hospital, Dept. of Neurology, Medical School, London (United Kingdom); Hardy, J [University of South Florida, Suncoast Alzheimer` s Disease Research Labs, Department of Psychiatry, Tampa (United States)

    1995-02-01

    Four disease-causing mutations have so far been described in the amyloid precursor protein gene on chromosome 21 in familial early-onset Alzheimer`s disease. Linkage analysis with a fourteen-allele microsatellite at D21S210 named GT-12 has proven useful in the elucidation of amyloid presursor protein gene involvement in Alzheimer`s disease families, as it is closely linked to the gene. Most cases of Alzheimer`s disease are thought to be sporadic and not familial. However, evidence from earlier studies suggests an important genetic contribution also in sporadic cases, where gene-environment interaction may contribute to the disease. We have determined frequencies of the GT-12 alleles in 78 Swedish and 49 British sporadic Alzheimer`s disease cases and 104 healthy elderly control subjects, to investigate if the disease associates with a particular genotype in GT-12. However, no differences in allele frequencies were observed between any of the groups. (au) (26 refs.).

  15. Heysham II/Torness AGR steam generator

    International Nuclear Information System (INIS)

    Charcharos, A.N.; Wood, M.B.; Glasgow, J.R.

    1988-01-01

    The AGR Steam Generators for Heysham II and Torness Power Stations have been installed at site and are being operated in the initial low temperature commissioning plant engineering tests. In this paper a description of the high pressure once-through steam generators together with layout arrangements, materials employed, operating parameters, plant operating conditions and constraints is given. An outline of the development of the design through thermo-hydraulic considerations, mechanical design, instrumentation to component testing is presented. Special features of the design directed to accommodate such requirements as seismic loadings, waterside static and dynamic stability, gas flow induced vibration, thermal expansions are described in detail. The fabrication facilities employed and techniques selected and developed for the manufacture and assembly of the heating surfaces are presented. These include welding processes, tube manipulation and heat treatment with details of the automation applied to the processes. Operating experience in the early commissioning plant engineering tests at Site is described with an emphasis on those tests which provide the final confirmation of the design prior to operation at full load. The paper concludes with a description of the outstanding commissioning activities up to raise power. (author)

  16. Heysham II/Torness AGR steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Charcharos, A N [National Nuclear Corporation Ltd., Knutsford (United Kingdom); Wood, M B; Glasgow, J R [NEI Power Projects Ltd., Gateshead (United Kingdom)

    1988-07-01

    The AGR Steam Generators for Heysham II and Torness Power Stations have been installed at site and are being operated in the initial low temperature commissioning plant engineering tests. In this paper a description of the high pressure once-through steam generators together with layout arrangements, materials employed, operating parameters, plant operating conditions and constraints is given. An outline of the development of the design through thermo-hydraulic considerations, mechanical design, instrumentation to component testing is presented. Special features of the design directed to accommodate such requirements as seismic loadings, waterside static and dynamic stability, gas flow induced vibration, thermal expansions are described in detail. The fabrication facilities employed and techniques selected and developed for the manufacture and assembly of the heating surfaces are presented. These include welding processes, tube manipulation and heat treatment with details of the automation applied to the processes. Operating experience in the early commissioning plant engineering tests at Site is described with an emphasis on those tests which provide the final confirmation of the design prior to operation at full load. The paper concludes with a description of the outstanding commissioning activities up to raise power. (author)

  17. Steam Digest 2001: Office of Industrial Technologies

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2002-01-01

    Steam Digest 2001 chronicles Best Practices Program's contributions to the industrial trade press for 2001, and presents articles that cover technical, financial and managerial aspects of steam optimization.

  18. Vapor generator steam drum spray heat

    International Nuclear Information System (INIS)

    Fasnacht, F.A. Jr.

    1978-01-01

    A typical embodiment of the invention provides a combination feedwater and cooldown water spray head that is centrally disposed in the lower portion of a nuclear power plant steam drum. This structure not only discharges the feedwater in the hottest part of the steam drum, but also increases the time required for the feedwater to reach the steam drum shell, thereby further increasing the feedwater temperature before it contacts the shell surface, thus reducing thermal shock to the steam drum structure

  19. Steam turbines for nuclear power plants

    International Nuclear Information System (INIS)

    Kosyak, Yu.F.

    1978-01-01

    Considered are the peculiarities of the design and operation of steam turbines, condensers and supplementary equipment of steam turbines for nuclear power plants; described are the processes of steam flow in humid-steam turbines, calculation and selection principles of main parameters of heat lines. Designs of the turbines installed at the Charkov turbine plant are described in detail as well as of those developed by leading foreign turbobuilding firms

  20. Flow oscillations on the steam control valve in the middle opening condition. Clarification of the phenomena by steam flow experiment and CFD calculation

    International Nuclear Information System (INIS)

    Morita, Ryo; Inada, Fumio

    2006-01-01

    A steam control valve might cause vibrations of piping when the valve opening is in a middle condition. For rationalization of maintenance and management of the plant, the valve should be improved, but it is difficult to understand flow characteristics in detail by experiment because flow around the valve is complex 3D structure and becomes supersonic (M>1). Therefore, it is necessary to clarify the cause of the vibrations and to develop improvements by Computational Fluid Dynamics (CFD) technology. In previous researches, we clarified a mechanism of the pressure fluctuations in the middle opening condition and suggested the way to prevent the pressure fluctuations by experiments and CFD calculations. But, as we used air as a working fluid in our previous research instead of steam that is used in the power plant, we couldn't consider effects of condensation and difference of change of the quantity of state between air and steam. In this report, we have conducted steam flow experiments by multi-purpose steam experiment apparatus 'WISSH' and CFD calculations by steam flow code 'MATIS-SC' to clarify those effects. As a result, in the middle opening condition, we have observed rotating pressure fluctuations in the experiment and valve-attached flow and local high-pressure region in the CFD result. These results show the pressure fluctuations in steam experiments and CFD is same kind of the fluctuations found in air experiment and CFD. (author)

  1. Passive system with steam-water injector for emergency supply of NPP steam generators

    International Nuclear Information System (INIS)

    Il'chenko, A.G.; Strakhov, A.N.; Magnitskij, D.N.

    2009-01-01

    The calculation results of reliability indicators of emergency power supply system and emergency feed-water supply system of serial WWER-1000 unit are presented. To ensure safe water supply to steam generators during station blackout it was suggested using additional passive emergency feed-water system with a steam-water injector working on steam generators dump steam. Calculated analysis of steam-water injector operating capacity was conducted at variable parameters of steam at the entrance to injector, corresponding to various moments of time from the beginning of steam-and-water damping [ru

  2. Parametric study for horizontal steam generator modelling

    Energy Technology Data Exchange (ETDEWEB)

    Ovtcharova, I. [Energoproekt, Sofia (Bulgaria)

    1995-12-31

    In the presentation some of the calculated results of horizontal steam generator PGV - 440 modelling with RELAP5/Mod3 are described. Two nodalization schemes have been used with different components in the steam dome. A study of parameters variation on the steam generator work and calculated results is made in cases with separator and branch.

  3. STEAM DALAM PEMBUATAN PAKAN UNTUK KOMODITAS AKUAKULTUR

    Directory of Open Access Journals (Sweden)

    Sukarman Sukarman

    2010-12-01

    Full Text Available Kualitas fisik pakan (pelet untuk hewan akuakultur sangat penting, karena akan dimasukkan ke dalam air dan diharapkan tidak banyak mencemari lingkungan. Salah satu faktor yang berpengaruh dalam menjaga kualitas fisik pakan adalah penambahan dan pengaturan steam pada saat proses pembuatan pelet. Steam adalah aliran gas yang dihasilkan oleh air pada saat mendidih. Steam dibagi menjadi 3 jenis yaitu steam basah, saturated steam, dan superheated steam. Steam yang digunakan dalam proses pembuatan pelet adalah saturated steam. Pengaruh penambahan steam pada kualitas pelet bisa mencapai 20%. Penambahan steam dengan jumlah dan kualitas yang tepat akan menghasilkan pelet berkualitas. Sedangkan jika pengaturan dan penambahannya tidak tepat, maka kualitas fisik pelet akan rendah dan kemungkinan bisa merusak kandungan nutrisi seperti vitamin dan protein. Penambahan steam yang benar bisa dilakukan di dalam kondisioner dengan mengatur retention time, sudut kemiringan paddle conditioner, kecepatan putaran bearing dan menjaga kualitas steam dari mesin boiler sampai dengan kondisioner.

  4. Parametric study for horizontal steam generator modelling

    Energy Technology Data Exchange (ETDEWEB)

    Ovtcharova, I [Energoproekt, Sofia (Bulgaria)

    1996-12-31

    In the presentation some of the calculated results of horizontal steam generator PGV - 440 modelling with RELAP5/Mod3 are described. Two nodalization schemes have been used with different components in the steam dome. A study of parameters variation on the steam generator work and calculated results is made in cases with separator and branch.

  5. Hybrid preheat/recirculating steam generator

    International Nuclear Information System (INIS)

    Lilly, G.P.

    1985-01-01

    The patent describes a hybrid preheat/recirculating steam generator for nuclear power plants. The steam generator utilizes recirculated liquid to preheat incoming liquid. In addition, the steam generator incorporates a divider so as to limit the amount of recirculating water mixed with the feedwater. (U.K.)

  6. BWR Steam Dryer Alternating Stress Assessment Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Morante, R. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hambric, S. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ziada, S. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-12-01

    This report presents an overview of Boiling Water Reactor (BWR) steam dryer design; the fatigue cracking failures that occurred at the Quad Cities (QC) plants and their root causes; a history of BWR Extended Power Uprates (EPUs) in the USA; and a discussion of steam dryer modifications/replacements, alternating stress mechanisms on steam dryers, and structural integrity evaluations (static and alternating stress).

  7. Fluid distribution network and steam generators and method for nuclear power plant training simulator

    International Nuclear Information System (INIS)

    Alliston, W.H.; Johnson, S.J.; Mutafelija, B.A.

    1975-01-01

    A description is given of a training simulator for the real-time dynamic operation of a nuclear power plant which utilizes apparatus that includes control consoles having manual and automatic devices corresponding to simulated plant components and indicating devices for monitoring physical values in the simulated plant. A digital computer configuration is connected to the control consoles to calculate the dynamic real-time simulated operation of the plant in accordance with the simulated plant components to provide output data including data for operating the control console indicating devices. In the method and system for simulating a fluid distribution network of the power plant, such as that which includes, for example, a main steam system which distributes steam from steam generators to high pressure turbine steam reheaters, steam dump valves, and feedwater heaters, the simultaneous solution of linearized non-linear algebraic equations is used to calculate all the flows throughout the simulated system. A plurality of parallel connected steam generators that supply steam to the system are simulated individually, and include the simulation of shrink-swell characteristics

  8. Materials Performance in USC Steam

    Energy Technology Data Exchange (ETDEWEB)

    G. R. Holcomb, P. Wang, P. D. Jablonski, and J. A. Hawk

    2010-05-01

    The proposed steam inlet temperature in the Advanced Ultra Supercritical (A-USC) steam turbine is high enough (760 °C) that traditional turbine casing and valve body materials such as ferritic/martensitic steels will not suffice due to temperature limitations of this class of materials. Cast versions of several traditionally wrought Ni-based superalloys were evaluated for use as casing or valve components for the next generation of industrial steam turbines. The full size castings are substantial: 2-5,000 kg each half and on the order of 100 cm thick. Experimental castings were quite a bit smaller, but section size was retained and cooling rate controlled to produce equivalent microstructures. A multi-step homogenization heat treatment was developed to better deploy the alloy constituents. The most successful of these cast alloys in terms of creep strength (Haynes 263, Haynes 282, and Nimonic 105) were subsequently evaluated by characterizing their microstructure as well as their steam oxidation resistance (at 760 and 800 °C).

  9. The STEAM behind the Scenes

    Science.gov (United States)

    Smith, Carmen Petrick; King, Barbara; González, Diana

    2015-01-01

    There is a growing need for STEAM-based (Science, Technology, Engineering, Arts, and Mathematics) knowledge and skills across a wide range of professions (Brazell 2013). Yet students often fail to see the usefulness of mathematics beyond the classroom (Kloosterman, Raymond, and Emenaker 1996), and they do not regularly make connections between…

  10. Technical diagnostics of steam turbines

    International Nuclear Information System (INIS)

    Vlckova, B.; Drahy, J.

    1987-01-01

    This paper deals with practical experience in application of technical diagnostics methods to steam turbines, in particular using pedestal and shaft vibration measurements as well as estimation of bearing metal temperature and ultrasound emission signals. An estimation of effectiveness of the diagnostics methods used is given on the basis of experimental investigations made on a 30-MW turbine. (author)

  11. Severity parameters for steam cracking

    NARCIS (Netherlands)

    Golombok, M.; Bijl, J.L.M.; Kornegoor, M.

    2001-01-01

    There are several ways to measure severity in steam cracking which are all a function of residence time, temperature, and pressure. Many measures of severity are not practicable for experimental purposes. Our experimental study shows that methane make is the best measure of severity because it is an

  12. Nuclear process steam for industry

    International Nuclear Information System (INIS)

    Seddon, W.A.

    1981-11-01

    A joint industrial survey funded by the Bruce County Council, the Ontario Energy Corporation and Atomic Energy of Canada Limited was carried out with the cooperation of Ontario Hydro and the Ontario Ministry of Industry and Tourism. Its objective was to identify and assess the future needs and interest of energy-intensive industries in an Industrial Energy Park adjacent to the Bruce Nuclear Power Development. The Energy Park would capitalize on the infrastructure of the existing CANDU reactors and Ontario Hydro's proven and unique capability to produce steam, as well as electricity, at a cost currently about half that from a comparable coal-fired station. Four industries with an integrated steam demand of some 1 x 10 6 lb/h were found to be prepared to consider seriously the use of nuclear steam. Their combined plants would involve a capital investment of over $200 million and provide jobs for 350-400 people. The high costs of transportation and the lack of docking facilities were considered to be the major drawbacks of the Bruce location. An indication of steam prices would be required for an over-all economic assessment

  13. Steam initiated hydrotalcite conversion coatings

    DEFF Research Database (Denmark)

    Zhou, Lingli; Friis, Henrik; Roefzaad, Melanie

    2018-01-01

    A facile process of exploiting high-temperature steam to deposit nvironmentally friendly hydrotalcite (HT) coatings on Al alloy 6060 was developed in a spray system. Scanning electron microscopy showed the formationf a continuous and conformal coating comprised of a compact mass of crystallites. ...

  14. Steam-water relative permeability

    Energy Technology Data Exchange (ETDEWEB)

    Ambusso, W.; Satik, C.; Home, R.N. [Stanford Univ., CA (United States)

    1997-12-31

    A set of relative permeability relations for simultaneous flow of steam and water in porous media have been measured in steady state experiments conducted under the conditions that eliminate most errors associated with saturation and pressure measurements. These relations show that the relative permeabilities for steam-water flow in porous media vary approximately linearly with saturation. This departure from the nitrogen/water behavior indicates that there are fundamental differences between steam/water and nitrogen/water flows. The saturations in these experiments were measured by using a high resolution X-ray computer tomography (CT) scanner. In addition the pressure gradients were obtained from the measurements of liquid phase pressure over the portions with flat saturation profiles. These two aspects constitute a major improvement in the experimental method compared to those used in the past. Comparison of the saturation profiles measured by the X-ray CT scanner during the experiments shows a good agreement with those predicted by numerical simulations. To obtain results that are applicable to general flow of steam and water in porous media similar experiments will be conducted at higher temperature and with porous rocks of different wetting characteristics and porosity distribution.

  15. Planning of the steam generators for nuclear applications using optimization techniques

    International Nuclear Information System (INIS)

    Sakai, M.; Silvares, O.M.

    1978-01-01

    Procedure for the maximization of the net power of a nuclear power plant through the application of the optimal control theory of dynamic systems is presented. The problem is formulated in the steam generator which links the primary and the secondary cycle. The solution of the steam generator, optimization problem is obtained simultaneously with the heat balance in both primary and secondary cycle, through an iterative process. By this way the optimal parameters are obtained for the steam generator, the vapor and the cooling gas cycle [pt

  16. Optimization of the steam generator project of a gas cooled nuclear reactor

    International Nuclear Information System (INIS)

    Sakai, Massao

    1978-01-01

    The present work is concerned with the modeling of the primary and secondary circuits of a gas cooled nuclear reactor in order to obtain the relation between the parameters of the two cycles and the steam generator performance. The procedure allows the optimization of the steam generator, through the maximization of the plant net power, and the application of the optimal control theory of dynamic systems. The heat balances for the primary and secondary circuits are carried out simultaneously with the optimized - design parameters of the steam generator, obtained using an iterative technique. (author)

  17. The Steam Generating Heavy Water Reactor

    International Nuclear Information System (INIS)

    Middleton, J.E.

    1975-01-01

    An account is given of the SGHWR, the prototype of which was built by the United Kingdom Atomic Energy Authority at Winfrith, under the following headings: Introduction; origin of the SGHWR concept; conceptual design (choice of reactor type, steam cycle, reactor coolant system, nuclear behaviour, fuel design, core design, and protective, auxiliary and containment systems); operation and control (integrity of core cooling, reactivity control, power trimming, long term reactivity control, xenon override, load following, power shaping, spatial stability control, void coefficient); protective systems (breached coolant circuit trip, intact coolant circuits trip, power set-back trip); dynamic characteristics; reactor control; station control (decoupled control system, coupled control system, rate of response); Winfrith prototype (design and safety philosophy, conceptual features and parameters, reactor coolant system, protective systems, emergency core cooling, core structure, fuel design, vented containment). (U.K.)

  18. The evaluation of MCI, MI, PMI and GT on both genders with different age and dental status.

    Science.gov (United States)

    Bozdag, G; Sener, S

    2015-01-01

    The aim of this study was to measure the mandibular cortical index (MCI), mental index (MI), panoramic mandibular index (PMI) and cortical bone thickness in the zone of the gonial angle (GT) in panoramic radiographies from a large sample of males and females and to determine how they relate to patients' age, gender and dental status. 910 panoramic radiographs were obtained and grouped into age, dental status and gender. The MCI, MI, PMI and GT were analysed. Remarkable differences were observed for MCI and GT regarding gender, age groups and dental status on both sides (p PMI in females, dental status had an effect on the MI and PMI in males (p PMI (p PMI and MI measurements. The effects of age and tooth loss in the GT and MCI measurements are similar, and these indices can be accepted as more reliable in studies including both genders.

  19. Steam jet ejectors are examined automatically

    International Nuclear Information System (INIS)

    Lardiere, C.

    2013-01-01

    Steam jet ejectors are used in the nuclear industry particularly for the transfer of radioactive fluids. Their working is based on the Venturi effect and the conservation of energy. A steam ejector can be considered as a thermodynamical pump without mobile parts. The Descote enterprise manufactures a broad range of steam jet ejectors and the characterization and testing of the steam ejectors was made manually and empirically so far. A new test bench has been designed, the tests are led automatically and allow a more accurate characterization and optimization of the steam jet ejectors. (A.C.)

  20. Facility to separate water and steam

    International Nuclear Information System (INIS)

    Loesel, G.

    1977-01-01

    The water/steam mixture from the pressure vessel e.g. of a BWR is separated by means of centrifugal separators untilizing the natural separation of steam. The steam is supplied to a steam drying vessel and the water to a water collecting tank. These vessels may be combined to a common vessel or connected through additional pipes. From the water collecting tank, arranged below the steam dryer, a feedwater pipe runs back to the pressure vessel. By construction out of individual components cleaning, decontamination, and operating control are essentially simplified. (RW) 891 RW [de

  1. Cycle improvement for nuclear steam power plant

    International Nuclear Information System (INIS)

    Silvestri, G.J. Jr.

    1976-01-01

    A pressure-increasig ejector element is disposed in an extraction line intermediate to a high pressure turbine element and a feedwater heater. The ejector utilizes high pressure fluid from a reheater drain as the motive fluid to increase the pressure at which the extraction steam is introduced into the feedwater heater. The increase in pressure of the extraction steam entering the feedwater heater due to the steam passage through the ejector increases the heat exchange capability of the extraction steam thus increasing the overall steam power plant efficiency

  2. Structural analysis of steam generator internals following feed water main steam line break: DLF approach

    International Nuclear Information System (INIS)

    Bhasin, Vivek; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

    1993-01-01

    In order to evaluate the possible release of radioactivity in extreme events, some postulated accidents are analysed and studied during the design stage of Steam Generator (SG). Among the various accidents postulated, the most important are Feed Water Line Break (FWLB) and Main Steam Line Break (MSLB). This report concerns with dynamic structural analysis of SG internals following FWLB/MSLB. The pressure/drag-force time histories considered were corresponding to the conditions leading to the accident of maximum potential. The SG internals were analysed using two approaches of structural dynamics. In first approach simplified DLF method was adopted. This method yields an upper bound values of stresses and deflection. In the second approach time history analysis by Mode Superposition Technique was adopted. This approach gives more realistic results. The structure was qualified as per ASME B and PV Code SecIII NB. It was concluded that in all the components except perforated flow distribution plate, the stress values based on elastic analysis are within the limits specified by ASME Code. In case of perforated flow distribution plate during the MSLB transient the stress values based on elastic analysis are higher than the ASME Code limits. Therefore, its limit load analysis had to be done. Finally, the collapse pressure evaluated using limit load analysis was shown to be within the limits of ASME B and PV Code SecIII Nb. (author). 31 refs., 94 figs., 16 tabs

  3. Replication study of STAT4 rs7574865 G/T polymorphism and risk of rheumatoid arthritis in a Chinese population.

    Science.gov (United States)

    Shen, Li; Liu, Ruiping; Zhang, Hui; Huang, Yong; Sun, Rongbin; Tang, Peifu

    2013-09-10

    Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are common systemic autoimmune diseases with genetic and environmental predisposing factors. Signal transducer and activator of transcription 4 (STAT4) transmits signals induced by interleukin-12, interleukin-23 and interferon-γ, which are key cytokines and play important roles in the development of autoimmune diseases. Previous studies confirmed the STAT4 rs7574865 G/T locus to be associated with RA. Thus we conducted a replication study to investigate STAT4 rs7574865 G/T polymorphism and RA/AS susceptibility in a Chinese population. We studied STAT4 rs7574865 G/T gene polymorphism in 520 patients with RA, 100 AS patients and 520 controls in a Chinese population. Genotyping was done using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). When the STAT4 rs7574865 GG homozygote genotype was used as the reference group, the GT or GT/TT genotypes were associated with the risk for RA. After stratification analyses, a significantly increased risk for RA associated with the STAT4 rs7574865 GT genotype was evident among the rheumatoid factor (RF)-positive patients, patients with higher erythrocyte sedimentation rate (ESR) level and patients with higher RA disease activity score (DAS28) compared with the STAT4 rs7574865 GG genotype. A significantly increased risk for RA associated with the STAT4 rs7574865 TT genotype was evident among older patients and RF-negative patients compared with the STAT4 rs7574865 GG genotype. STAT4 rs7574865 G/T was not associated with susceptibility to AS. This replication study confirmed that STAT4 rs7574865 G/T polymorphism was associated with the risk of RA. STAT4 polymorphisms are associated with rheumatoid arthritis risk. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Modeling of steam generator in nuclear power plant using neural network ensemble

    International Nuclear Information System (INIS)

    Lee, S. K.; Lee, E. C.; Jang, J. W.

    2003-01-01

    Neural network is now being used in modeling the steam generator is known to be difficult due to the reverse dynamics. However, Neural network is prone to the problem of overfitting. This paper investigates the use of neural network combining methods to model steam generator water level and compares with single neural network. The results show that neural network ensemble is effective tool which can offer improved generalization, lower dependence of the training set and reduced training time

  5. On line instrument systems for monitoring steam turbogenerators

    Science.gov (United States)

    Clapis, A.; Giorgetti, G.; Lapini, G. L.; Benanti, A.; Frigeri, C.; Gadda, E.; Mantino, E.

    A computerized real time data acquisition and data processing for the diagnosis of malfunctioning of steam turbogenerator systems is described. Pressure, vibration and temperature measurements are continuously collected from standard or special sensors including startup or stop events. The architecture of the monitoring system is detailed. Examples of the graphics output are presented. It is shown that such a system allows accurate diagnosis and the possibility of creating a data bank to describe the dynamic characteristics of the machine park.

  6. Horizontal steam generator thermal-hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O. [SKODA Praha Company, Prague (Czechoslovakia); Doubek, M. [Czech Technical Univ., Prague (Czechoslovakia)

    1995-09-01

    Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. The 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.

  7. Model and control scheme for recirculation mode direct steam generation parabolic trough solar power plants

    International Nuclear Information System (INIS)

    Guo, Su; Liu, Deyou; Chen, Xingying; Chu, Yinghao; Xu, Chang; Liu, Qunming; Zhou, Ling

    2017-01-01

    Highlights: •A nonlinear dynamic model of recirculation DSG parabolic trough is developed. •Collector row, water separator and spray attemperator are modeled, respectively. •The dynamic behaviors of the collector field are simulated and analyzed. •Transfer functions of water level and outlet fluid temperature are derived. •Multi-model switching generalized predictive control strategy is developed. -- Abstract: This work describes and evaluates a new nonlinear dynamic model, and a new generalized predictive control scheme for a collector field of direct steam generation parabolic troughs in recirculation mode. Modeling the dynamic behaviors of collector fields is essential to design, testing and validation of automatic control systems for direct steam generation parabolic troughs. However, the behaviors of two-phase heat transfer fluids impose challenges to simulating and developing process control schemes. In this work, a new nonlinear dynamic model is proposed, based on the nonlinear distributed parameter and the nonlinear lumped parameter methods. The proposed model is used to simulate and analyze the dynamic behaviors of the entire collector field for recirculation mode direct steam generation parabolic troughs under different weather conditions, without excessive computational costs. Based on the proposed model, transfer functions for both the water level of the separator and outlet steam temperatures are derived, and a new multi-model switching generalized predictive control scheme is developed for simulated control of the plant behaviors for a wide region of operational conditions. The proposed control scheme achieves excellent control performance and robustness for systems with long delay, large inertia and time-varying parameters, and efficiently solves the model mismatching problem in direct steam generation parabolic troughs. The performances of the model and control scheme are validated with design data from the project of Integration of Direct

  8. Chemical Looping Combustion of Hematite Ore with Methane and Steam in a Fluidized Bed Reactor

    Directory of Open Access Journals (Sweden)

    Samuel Bayham

    2017-08-01

    Full Text Available Chemical looping combustion is considered an indirect method of oxidizing a carbonaceous fuel, utilizing a metal oxide oxygen carrier to provide oxygen to the fuel. The advantage is the significantly reduced energy penalty for separating out the CO2 for reuse or sequestration in a carbon-constrained world. One of the major issues with chemical looping combustion is the cost of the oxygen carrier. Hematite ore is a proposed oxygen carrier due to its high strength and resistance to mechanical attrition, but its reactivity is rather poor compared to tailored oxygen carriers. This problem is further exacerbated by methane cracking, the subsequent deposition of carbon and the inability to transfer oxygen at a sufficient rate from the core of the particle to the surface for fuel conversion to CO2. Oxygen needs to be readily available at the surface to prevent methane cracking. The purpose of this work was to demonstrate the use of steam to overcome this issue and improve the conversion of the natural gas to CO2, as well as to provide data for computational fluid dynamics (CFD validation. The steam will gasify the deposited carbon to promote the methane conversion. This work studies the performance of hematite ore with methane and steam mixtures in a 5 cm fluidized bed up to approximately 140 kPa. Results show an increased conversion of methane in the presence of steam (from 20–45% without steam to 60–95% up to a certain point, where performance decreases. Adding steam allows the methane conversion to carbon dioxide to be similar to the overall methane conversion; it also helped to prevent carbon accumulation from occurring on the particle. In general, the addition of steam to the feed gas increased the methane conversion. Furthermore, the addition of steam caused the steam methane reforming reaction to form more hydrogen and carbon monoxide at higher steam and methane concentrations, which was not completely converted at higher concentrations and

  9. Experimental fretting-wear studies of steam generator materials

    International Nuclear Information System (INIS)

    Fisher, N.J.; Chow, A.B.; Weckwerth, M.K.

    1994-01-01

    Flow-induced vibration of steam generator tubes results in fretting-wear damage due to impacting and rubbing of the tubes against their supports. This damage can be predicted by computing tube response to flow-induced excitation forces using analytical techniques, and then relating this response to resultant wear damage using experimentally-derived wear coefficients. Fretting-wear of steam generator materials has been studied experimentally at Chalk River Laboratories for two decades. Tests are conducted in machines that simulate steam generator environmental conditions and tube-to-support dynamic interactions. Different tube and support materials, tube-to-support clearances and tube support geometries have been studied. As well, the effect of environmental conditions, such as temperature, oxygen content, pH and chemistry control additive, have been investigated. Early studies showed that damage was related to contact force as long as other parameters, such as geometry and motion were held constant. Later studies have shown that damage is related to a parameter called work-rate, which combines both contact force and sliding distance. Results of short- and long-term fretting-wear tests for CANDU steam generator materials at realistic environmental conditions are presented. These results demonstrate that work-rate is appropriate correlating parameter for impact-sliding interaction

  10. Steam generators clogging diagnosis through physical and statistical modelling

    International Nuclear Information System (INIS)

    Girard, S.

    2012-01-01

    Steam generators are massive heat exchangers feeding the turbines of pressurised water nuclear power plants. Internal parts of steam generators foul up with iron oxides which gradually close some holes aimed for the passing of the fluid. This phenomenon called clogging causes safety issues and means to assess it are needed to optimise the maintenance strategy. The approach investigated in this thesis is the analysis of steam generators dynamic behaviour during power transients with a mono dimensional physical model. Two improvements to the model have been implemented. One was taking into account flows orthogonal to the modelling axis, the other was introducing a slip between phases accounting for velocity difference between liquid water and steam. These two elements increased the model's degrees of freedom and improved the adequacy of the simulation to plant data. A new calibration and validation methodology has been proposed to assess the robustness of the model. The initial inverse problem was ill posed: different clogging spatial configurations can produce identical responses. The relative importance of clogging, depending on its localisation, has been estimated by sensitivity analysis with the Sobol' method. The dimension of the model functional output had been previously reduced by principal components analysis. Finally, the input dimension has been reduced by a technique called sliced inverse regression. Based on this new framework, a new diagnosis methodology, more robust and better understood than the existing one, has been proposed. (author)

  11. Steam atmosphere drying concepts using steam exhaust recompression

    Energy Technology Data Exchange (ETDEWEB)

    DiBella, F.A. (TECOGEN, Inc., Waltham, MA (United States))

    1992-08-01

    In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg[sub evap] to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

  12. Steam atmosphere drying concepts using steam exhaust recompression

    Energy Technology Data Exchange (ETDEWEB)

    DiBella, F.A. [TECOGEN, Inc., Waltham, MA (United States)

    1992-08-01

    In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg{sub evap} to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

  13. Unsteady coupling effects of wet steam in steam turbines flows

    International Nuclear Information System (INIS)

    Blondel, Frederic

    2014-01-01

    In addition to conventional turbomachinery problems, both the behavior and performances of steam turbines are highly dependent on the vapour thermodynamic state and the presence of a liquid phase. EDF, the main French electricity producer, is interested in further developing its' modelling capabilities and expertise in this area to allow for operational studies and long-term planning. This PhD thesis explores the modelling of wetness formation and growth in a steam turbine and an analysis of the coupling between the liquid phase and the main flow unsteadiness. To this end, the work in this thesis took the following approach. Wetness was accounted for using a homogeneous model coupled with transport equations to take into account the effects of non-equilibrium phenomena, such as the growth of the liquid phase and nucleation. The real gas attributes of the problem demanded adapted numerical methods. Before their implementation in the 3D elsA solver, the accuracy of the chosen models was tested using a developed one-dimensional nozzle code. In this manner, various condensation models were considered, including both poly-dispersed and monodispersed behaviours of the steam. Finally, unsteady coupling effects were observed from several perspectives (1D, 1D - 3D, 3D), demonstrating the ability of the method of moments to sustain unsteady phenomena which were not apparent in a simple monodispersed model. (author)

  14. FSV experience in support of the GT-MHR reactor physics, fuel performance, and graphite

    International Nuclear Information System (INIS)

    Baxter, A.M.; McEachern, D.; Hanson, D.L.; Vollman, R.E.

    1994-11-01

    The Fort St. Vrain (FSV) power plant was the most recent operating graphite-moderated, helium-cooled nuclear power plant in the United States. Many similarities exist between the FSV design and the current design of the GT-MHR. Both designs use graphite as the basic building blocks of the core, as structural material, in the reflectors, and as a neutron moderator. Both designs use hexagonal fuel elements containing cylindrical fuel rods with coated fuel particles. Helium is the coolant and the power densities vary by less than 5%. Since material and geometric properties of the GT-MHR core am very similar to the FSV core, it is logical to draw upon the FSV experience in support of the GT-MHR design. In the Physics area, testing at FSV during the first three cycles of operation has confirmed that the calculational models used for the core design were very successful in predicting the core nuclear performance from initial cold criticality through power operation and refueling. There was excellent agreement between predicted and measured initial core criticality and control rod positions during startup. Measured axial flux distributions were within 5% of the predicted value at the peak. The isothermal temperature coefficient at zero power was in agreement within 3%, and even the calculated temperature defect over the whole operating range for cycle 3 was within 8% of the measured defect. In the Fuel Performance area, fuel particle coating performance, and fission gas release predictions and an overall plateout analysis were performed for decommissioning purposes. A comparison between predicted and measured fission gas release histories of Kr-85m and Xe-138 and a similar comparison with specific circulator plateout data indicated good agreement between prediction and measured data. Only I-131 plateout data was overpredicted, while Cs-137 data was underpredicted

  15. Ground reaction force estimates from ActiGraph GT3X+ hip accelerations.

    Directory of Open Access Journals (Sweden)

    Jennifer M Neugebauer

    Full Text Available Simple methods to quantify ground reaction forces (GRFs outside a laboratory setting are needed to understand daily loading sustained by the body. Here, we present methods to estimate peak vertical GRF (pGRFvert and peak braking GRF (pGRFbrake in adults using raw hip activity monitor (AM acceleration data. The purpose of this study was to develop a statistically based model to estimate pGRFvert and pGRFbrake during walking and running from ActiGraph GT3X+ AM acceleration data. 19 males and 20 females (age 21.2 ± 1.3 years, height 1.73 ± 0.12 m, mass 67.6 ± 11.5 kg wore an ActiGraph GT3X+ AM over their right hip. Six walking and six running trials (0.95-2.19 and 2.20-4.10 m/s, respectively were completed. Average of the peak vertical and anterior/posterior AM acceleration (ACCvert and ACCbrake, respectively and pGRFvert and pGRFbrake during the stance phase of gait were determined. Thirty randomly selected subjects served as the training dataset to develop generalized equations to predict pGRFvert and pGRFbrake. Using a holdout approach, the remaining 9 subjects were used to test the accuracy of the models. Generalized equations to predict pGRFvert and pGRFbrake included ACCvert and ACCbrake, respectively, mass, type of locomotion (walk or run, and type of locomotion acceleration interaction. The average absolute percent differences between actual and predicted pGRFvert and pGRFbrake were 8.3% and 17.8%, respectively, when the models were applied to the test dataset. Repeated measures generalized regression equations were developed to predict pGRFvert and pGRFbrake from ActiGraph GT3X+ AM acceleration for young adults walking and running. These equations provide a means to estimate GRFs without a force plate.

  16. Models development for the fuel design of a reactor GT-MHR

    International Nuclear Information System (INIS)

    Telesforo R, D.; Francois L, J. L.

    2009-10-01

    The very high temperature reactor (VHTR) it as arisen as an option for the following reactors generation, due to their characteristics as they are inherent security, modularity and relative low cost. One of the VHTR variants, for its fuel based on prismatic blocks, is the modular reactor cooled by gas GT-MHR that uses a fuel particle of multiple layers called TRISO. These particles are small containers with fuel in their interior and they function as small pressure vessels that retain the fission products. They are absorbed inconstant ing in a cylindrical graphite matrix to form the fuel named Compact; the quantity of fuel inventory is proportional to the packaging fraction on the total volume of the Compact. The reactor consists of a matrix of 12 X 12 graphite hexagonal assemblies contained in a cylinder of 3.5 radio meters and 10.0 meters high. The nucleus has ten axial regions with 36 X 3 fuel assemblies distributed in three rings. For the neutronic modeling of the fuel and the nucleus it was employee the Monte Carlo method, using the code MCNPX (Monte Carlo N-Particle version X) that is a transport code of general purposes that uses this method with a great versatility in the representation of arbitrary three-dimensional configurations and materials configuration. The heterogeneous model of the reactor GT-MHR core was obtained, adjusting the relative parameters at core prototype GT-MHR presented by General Atomics. To prove the model it was employee the fuel formed by TRISO particles, with a nucleus of 150 μm and packaging fraction of 37.55%, with a Uranium-235 mixture, as fissile nuclide, and Thorium-232. To create a simplified model of the nucleus, or homogeneous model, without modeling any particle, it was employee the reactivity-equivalent physical transformation method that captures the effects of the heterogeneity double of the fuel region in two homogeneous equivalent cells, being obtained very good results. (Author)

  17. Research on vibration properties of auxiliary bearing cage used in HTR-10 GT project

    International Nuclear Information System (INIS)

    Qin Qingquan; Yang Guojun; Shi Zhengang; Yu Suyuan

    2009-01-01

    Auxiliary Bearings (ABs) is one of the most important parts in Active Magnetic Bearing (AMB) system, which was used in HTR-10 GT project. This paper uses finite element method to analyze the centrifugal stress and free vibration properties of the cage according to its work condition. And different geometric parameters of the cage that has effects on its vibration performance are discussed. The results show that the highest centrifugal stress is in the middle of the cage side sill. The low odder vibration modes of the cage can be induced when the auxiliary bearings are working. Proper geometric parameters and ball pocket number can enhance the performance of the cage. (authors)

  18. Colletotrichine B, a new sesquiterpenoid from Colletotrichum gloeosporioides GT-7, a fungal endophyte of Uncaria rhynchophylla.

    Science.gov (United States)

    Chen, Xiao-Wei; Yang, Zhong-Duo; Li, Xiao-Fei; Sun, Jian-Hui; Yang, Li-Jun; Zhang, Xin-Guo

    2018-02-08

    One new compound, colletotrichine B (1), was produced by the fungal Colletotrichum gloeosporioides GT-7. The structure of 1 was elucidated on the basis of spectroscopic analysis and X-ray crystallographic analysis. Monoamine oxidase (MAO), acetylcholinesterase (AChE) and phosphoinositide 3-kinase (PI3Kα) inhibitory activity of 1 was also evaluated. Compound 1 showed only AChE inhibiting activity with IC 50 value of 38.0 ± 2.67 μg/mL.

  19. Changing the simualtor's steam generator

    International Nuclear Information System (INIS)

    Ruiz Martin, J.A.; Ortega Pascual, F.

    2006-01-01

    Two Spanish nuclear power plants (two PWR units each one) have planned to change their Westinghouse D-3 steam generators (SGo henceforth) for a new model, 61W/D3 from Siemens/KWU (SGn henceforth), during 1995/1997. This is the reason why TECNATOM has developed during 1994's last term, a new software for the full scope simulator that incorporates the modifications related to the steam generator substiution programme. This allows an anticipated training on the procedures, not only for normal, but for emergency procedures. As it is a component which has not yet been included in these plants, there are not real references or operative experience data. Therefore, the design of the validation strategy was one of the key points in this work. (author)

  20. Steam coal mines of tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    McCloskey, G

    1986-07-01

    A comprehensive review of new steam coal mines being planned or developed worldwide. It shows that at least 20 major mines with a combined annual output of 110 million tonnes per annum, could add their coal to world markets in the next 10 years. The review highlights: substantial activity in Australia with at least four major mines at advanced planning stages; a strengthening of the South American export industry with 4 major mines operating in 10 years compared with just one today; no major export mines being developed in the traditional US mining areas; and the emergence of Indonesia as a major steam coal producer/exporter. The review also shows a reduction in cost/output ratios, and also the proximity of the new mines to existing infrastructure (e.g. export terminals, rail links).

  1. Organic evaporator steam valve failure

    International Nuclear Information System (INIS)

    Jacobs, R.A.

    1992-01-01

    Defense Waste Processing Facility (DWPF) Technical has requested an analysis of the capacity of the Organic Evaporator (OE) condenser (OEC) be performed to determine its capability in the case where the OE steam flow control valve fails open. Calculations of the OE boilup and the OEC heat transfer coefficient indicate the OEC will have more than enough capacity to remove the heat at maximum OE boilup. In fact, the Salt Cell Vent Condenser (SCVC) should also have sufficient capacity to handle the maximum OE boilup. Therefore, it would require simultaneous loss of OEC and/or SCVC condensing capacity for the steam valve failure to cause high benzene in the Process Vessel Vent System (PVVS)

  2. Closed loop steam cooled airfoil

    Science.gov (United States)

    Widrig, Scott M.; Rudolph, Ronald J.; Wagner, Gregg P.

    2006-04-18

    An airfoil, a method of manufacturing an airfoil, and a system for cooling an airfoil is provided. The cooling system can be used with an airfoil located in the first stages of a combustion turbine within a combined cycle power generation plant and involves flowing closed loop steam through a pin array set within an airfoil. The airfoil can comprise a cavity having a cooling chamber bounded by an interior wall and an exterior wall so that steam can enter the cavity, pass through the pin array, and then return to the cavity to thereby cool the airfoil. The method of manufacturing an airfoil can include a type of lost wax investment casting process in which a pin array is cast into an airfoil to form a cooling chamber.

  3. Steam generator waterlancing at DNGS

    International Nuclear Information System (INIS)

    Seppala, D.; Malaugh, J.

    1995-01-01

    Darlington Nuclear Generating Station (DNGS) is a four 900 MW Unit nuclear station forming part of the Ontario Hydro East System. There are four identical steam generators(SGs) per reactor unit. The Darlington SGs are vertical heat exchangers with an inverted U-tube bundle in a cylindrical shell. The DNGS Nuclear Plant Life Assurance Group , a department of DNGS Engineering Services have taken a Proactive Approach to ensure long term SG integrity. Instead of waiting until the tubesheets are covered by a substantial and established hard deposit; DNGS plan to clean each steam generator's tubesheet, first half lattice tube support assembly and bottom of the thermal plate every four years. The ten year business plan provides for cleaning and inspection to be conducted on all four SGs in each unit during maintenance outages (currently scheduled for every four years)

  4. Corrosion of PWR steam generators

    International Nuclear Information System (INIS)

    Garnsey, R.

    1979-01-01

    Some designs of pressurized water reactor (PWR) steam generators have experienced a variety of corrosion problems which include stress corrosion cracking, tube thinning, pitting, fatigue, erosion-corrosion and support plate corrosion resulting in 'denting'. Large international research programmes have been mounted to investigate the phenomena. The operational experience is reviewed and mechanisms which have been proposed to explain the corrosion damage are presented. The implications for design development and for boiler and feedwater control are discussed. (author)

  5. Large nuclear steam turbine plants

    International Nuclear Information System (INIS)

    Urushidani, Haruo; Moriya, Shin-ichi; Tsuji, Kunio; Fujita, Isao; Ebata, Sakae; Nagai, Yoji.

    1986-01-01

    The technical development of the large capacity steam turbines for ABWR plants was partially completed, and that in progress is expected to be completed soon. In this report, the outline of those new technologies is described. As the technologies for increasing the capacity and heightening the efficiency, 52 in long blades and moisture separating heaters are explained. Besides, in the large bore butterfly valves developed for making the layout compact, the effect of thermal efficiency rise due to the reduction of pressure loss can be expected. As the new technology on the system side, the simplification of the turbine system and the effect of heightening the thermal efficiency by high pressure and low pressure drain pumping-up method based on the recent improvement of feed water quality are discussed. As for nuclear steam turbines, the actual records of performance of 1100 MW class, the largest output at present, have been obtained, and as a next large capacity machine, the development of a steam turbine of 1300 MWe class for an ABWR plant is in progress. It can be expected that by the introduction of those new technologies, the plants having high economical efficiency are realized. (Kako, I.)

  6. Optimal design of marine steam turbine

    International Nuclear Information System (INIS)

    Liu Chengyang; Yan Changqi; Wang Jianjun

    2012-01-01

    The marine steam turbine is one of the key equipment in marine power plant, and it tends to using high power steam turbine, which makes the steam turbine to be heavier and larger, it causes difficulties to the design and arrangement of the steam turbine, and the marine maneuverability is seriously influenced. Therefore, it is necessary to apply optimization techniques to the design of the steam turbine in order to achieve the minimum weight or volume by means of finding the optimum combination of design parameters. The math model of the marine steam turbine design calculation was established. The sensitivities of condenser pressure, power ratio of HP turbine with LP turbine, and the ratio of diameter with height at the end stage of LP turbine, which influence the weight of the marine steam turbine, were analyzed. The optimal design of the marine steam turbine, aiming at the weight minimization while satisfying the structure and performance constraints, was carried out with the hybrid particle swarm optimization algorithm. The results show that, steam turbine weight is reduced by 3.13% with the optimization scheme. Finally, the optimization results were analyzed, and the steam turbine optimization design direction was indicated. (authors)

  7. Steam generator design for solar towers using solar salt as heat transfer fluid

    Science.gov (United States)

    González-Gómez, Pedro Ángel; Petrakopoulou, Fontina; Briongos, Javier Villa; Santana, Domingo

    2017-06-01

    Since the operation of a concentrating solar power plant depends on the intermittent character of solar energy, the steam generator is subject to daily start-ups, stops and load variations. Faster start-up and load changes increase the plant flexibility and the daily energy production. However, it involves high thermal stresses on thick-walled components. Continuous operational conditions may eventually lead to a material failure. For these reasons, it is important to evaluate the transient behavior of the proposed designs in order to assure the reliability. The aim of this work is to analyze different steam generator designs for solar power tower plants using molten salt as heat transfer fluid. A conceptual steam generator design is proposed and associated heat transfer areas and steam drum size are calculated. Then, dynamic models for the main parts of the steam generator are developed to represent its transient performance. A temperature change rate that ensures safe hot start-up conditions is studied for the molten salt. The thermal stress evolution on the steam drum is calculated as key component of the steam generator.

  8. Development of new 6-speed manual transmission for SKYLINE GT-R; Skyline GT-R yo shingata 6 soku manual transmission no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Hayami, H.; Kawasaki, M.; Yamamoto, K.; Gaber, J. [Nissan Motor Co. Ltd., Tokyo (Japan)

    1999-06-01

    Described herein is a new 6-speed manual transmission (6MT), jointly developed for the new SKYLINE GT-R model. It adopts a close gear ratio, to realize light acceleration performance by improving drop of engine revolution number during the shift-up period by up to 12%. It has an increased synchro capacity by adopting a triple-cone synchro system for the first and second speeds, and double-cone synchro system for the third and fourth speeds, thereby decreasing shift operational force requirement by up to 35% from that for the conventional 5MT type. A non-symmetrical chamfer synchro structure is used for the second and third speeds, to reduce load generated when the speed is changed. The shift stroke is shortened by 24% by reviewing the dimensions. A high-rigidity shift lever and select stopper structure are adopted, to improve shift rigidity sensation. The transmission case is optimized, to reduce its weight while securing its rigidity. Transmission oil temperature is decreased by installing a cooling fan and increasing overdrive gear ratio. (NEDO)

  9. Brain pericyte-derived soluble factors enhance insulin sensitivity in GT1-7 hypothalamic neurons.

    Science.gov (United States)

    Takahashi, Hiroyuki; Takata, Fuyuko; Matsumoto, Junichi; Machida, Takashi; Yamauchi, Atsushi; Dohgu, Shinya; Kataoka, Yasufumi

    2015-02-20

    Insulin signaling in the hypothalamus plays an important role in food intake and glucose homeostasis. Hypothalamic neuronal functions are modulated by glial cells; these form an extensive network connecting the neurons and cerebral vasculature, known as the neurovascular unit (NVU). Brain pericytes are periendothelial accessory structures of the blood-brain barrier and integral members of the NVU. However, the interaction between pericytes and neurons is largely unexplored. Here, we investigate whether brain pericytes could affect hypothalamic neuronal insulin signaling. Our immunohistochemical observations demonstrated the existence of pericytes in the mouse hypothalamus, exhibiting immunoreactivity of platelet-derived growth factor receptor β (a pericyte marker), and laminin, a basal lamina marker. We then exposed a murine hypothalamic neuronal cell line, GT1-7, to conditioned medium obtained from primary cultures of rat brain pericytes. Pericyte-conditioned medium (PCM), but not astrocyte- or aortic smooth muscle cell-conditioned medium, increased the insulin-stimulated phosphorylation of Akt in GT1-7 cells in a concentration-dependent manner. PCM also enhanced insulin-stimulated tyrosine phosphorylation of insulin receptor β without changing its expression or localization in cytosolic or plasma membrane fractions. These results suggest that pericytes, rather than astrocytes, increase insulin sensitivity in hypothalamic neurons by releasing soluble factors under physiological conditions in the NVU. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. GT-SUPREEM: the Georgia Tech summer undergraduate packaging research and engineering experience for minorities

    Science.gov (United States)

    May, Gary S.

    1996-07-01

    The Georgia Tech SUmmer Undergraduate Packaging Research and Engineering Experience for Minorities (GT-SUPREEM) is an eight-week summer program designed to attract qualified minority students to pursue graduate degrees in packaging- related disciplines. The program is conducted under the auspices of the Georgia Tech Engineering Research Center in Low-Cost Electronic Packaging, which is sponsored by the National Science Foundation. In this program, nine junior and senior level undergraduate students are selected on a nationwide basis and paired with a faculty advisor to undertake research projects in the Packaging Research CEnter. The students are housed on campus and provided with a $DLR3,000 stipend and a travel allowance. At the conclusion of the program, the students present both oral and written project summaries. It is anticipated that this experience will motivate these students to become applicants for graduate study in ensuring years. This paper will provide an overview of the GT-SUPREEM program, including student research activities, success stories, lessons learned, and overall program outlook.

  11. Endometrial cancer and somatic G>T KRAS transversion in patients with constitutional MUTYH biallelic mutations.

    Science.gov (United States)

    Tricarico, Rossella; Bet, Paola; Ciambotti, Benedetta; Di Gregorio, Carmela; Gatteschi, Beatrice; Gismondi, Viviana; Toschi, Benedetta; Tonelli, Francesco; Varesco, Liliana; Genuardi, Maurizio

    2009-02-18

    MUTYH-associated polyposis (MAP) is an autosomal recessive condition predisposing to colorectal cancer, caused by constitutional biallelic mutations in the base excision repair (BER) gene MUTYH. Colorectal tumours from MAP patients display an excess of somatic G>T mutations in the APC and KRAS genes due to defective BER function. To date, few extracolonic manifestations have been observed in MAP patients, and the clinical spectrum of this condition is not yet fully established. Recently, one patient with a diagnosis of endometrial cancer and biallelic MUTYH mutations has been described. We here report on two additional unrelated MAP patients with biallelic MUTYH germline mutations who developed endometrioid endometrial carcinoma. The endometrial tumours were evaluated for PTEN, PIK3CA, KRAS, BRAF and CTNNB1 mutations. A G>T transversion at codon 12 of the KRAS gene was observed in one tumour. A single 1bp frameshift deletion of PTEN was observed in the same sample. Overall, these findings suggest that endometrial carcinoma is a phenotypic manifestations of MAP and that inefficient repair of oxidative damage can be involved in its pathogenesis.

  12. Nuclear closed-cycle gas turbine (HTGR-GT): dry cooled commercial power plant studies

    International Nuclear Information System (INIS)

    McDonald, C.F.; Boland, C.R.

    1979-11-01

    Combining the modern and proven power conversion system of the closed-cycle gas turbine (CCGT) with an advanced high-temperature gas-cooled reactor (HTGR) results in a power plant well suited to projected utility needs into the 21st century. The gas turbine HTGR (HTGR-GT) power plant benefits are consistent with national energy goals, and the high power conversion efficiency potential satisfies increasingly important resource conservation demands. Established technology bases for the HTGR-GT are outlined, together with the extensive design and development program necessary to commercialize the nuclear CCGT plant for utility service in the 1990s. This paper outlines the most recent design studies by General Atomic for a dry-cooled commercial plant of 800 to 1200 MW(e) power, based on both non-intercooled and intercooled cycles, and discusses various primary system aspects. Details are given of the reactor turbine system (RTS) and on integrating the major power conversion components in the prestressed concrete reactor vessel

  13. A study on the design concepts of the PBMR and the GT-MHR

    International Nuclear Information System (INIS)

    Park, Won Seok; Chang, Jong Hwa; Park, Chang Kue

    2004-05-01

    The major application of the nuclear power in the energy sector has been to produce the electricity. However, a growing concern on the environment and the expected shortage of the fossil energy resources is demanding the expansion of nuclear energy's role in the energy sectors. The High Temperature Gas cooled Reactor (HTGR) has been expected to expand the role of nuclear energy because of its high temperature capability. Especially, the interest on the HTGR has been sharply increased recently related with the production of the hydrogen. About 5 HTGRs had been operated by the end of 1980s. However, all of them had been terminated permanently at the end of 1980s because of their poor system economy and frequent technical troubles. A new concept called MHTGR (Modular High Temperature Gas cooled Reactor) emerged in early of 1990s. Two MHTGR concepts on commercial basis have been developed since then; one is the PBMR (Pebble Bed Modular Reactor) developed by Eskom in South Africa and another is GT-MHR (Gas Turbine Modular High-temperature Reactor) developed by both GA in USA and OKBM in Russia. In this report, the design concepts for the PBMR and GT-MHR were reviewed

  14. Thermoeconomic analysis of Biomass Integrated Gasification Gas Turbine Combined Cycle (BIG GT CC) cogeneration plant

    Energy Technology Data Exchange (ETDEWEB)

    Arrieta, Felipe Raul Ponce; Lora, Electo Silva [Escola Federal de Engenharia de Itajuba, MG (Brazil). Nucleo de Estudos de Sistemas Termicos]. E-mails: aponce@iem.efei.br; electo@iem.efei.br; Perez, Silvia Azucena Nebra de [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia]. E-mail: sanebra@fem. unicamp.br

    2000-07-01

    Using thermoeconomics as a tool to identify the location and magnitude of the real thermodynamic losses (energy waste, or exergy destruction and exergy losses) it is possible to assess the production costs of each product (electric power and heat) and the exergetic and exergoeconomic cost of each flow in a cogeneration plant to assist in decision-marketing procedures concerning to plant design, investment, operation and allocations of research funds. Thermo economic analysis of Biomass Integrated Gasification Gas Turbine Combined Cycle (BIG GT CC) cogeneration plant for its applications in sugar cane mills brings the following results: the global exergetic efficiency is low; the highest irreversibilities occur in the following equipment, by order: scrubber (38%), gas turbine (16%), dryer (12%), gasifier and HRSG (6%); due to the adopted cost distribution methodology, the unit exergetic cost of the heat (4,11) is lower than electricity (4,71); the lower market price of biomass is one of the most sensible parameter in the possible implementation of BIG-GT technology in sugar cane industry; the production costs are 31 US$/MWh and 32 US$/MWh for electricity and heat, respectively. The electricity cost is, after all, competitive with the actual market price. The electricity and heat costs are lower or almost equal than other values reported for actual Rankine cycle cogeneration plants. (author)

  15. The GT-MHR - clear, economic, and safe power for the Pacific Rim

    International Nuclear Information System (INIS)

    Blue, L.S.; Etzel, K.T.; Simon, W.A.; Wistrom, J.D.

    1994-01-01

    In recent decades the nations of the Pacific Rim have outpaced the rest of the world in economic growth. Beyond an abundant labor market and the region's natural resources, energy has played a pivotal role in fuelling this boom. The diverse sources of this energy largely reflect the naturally occurring fuel assets in the Rim countries. Only in the countries where these resources are less plentiful has nuclear energy become a significant sources of electric power generation. Persuasive as the argument for non-polluting power may be by itself it does not sell the nuclear energy option. In addition to being clean it must also be economically competitive and very safe. The authors claim that the Gas-Turbine Modular Helium Reactor (GT-MHR) is an advances nuclear power system that addresses the issues, and should be viewed as an attractive candidate to meet future energy needs. The GT-MHR derives from the coupling of a small, passively safe, modular reactor directly with a compact power conversion module. It uses the Brayton cycle to produce electricity directly with the primary helium coolant driving the turbine-generator. Thus, it shows promise for a quantum reduction in power generation costs by increasing plant efficiency to a remarkable 48% This paper highlights the advantages of the fact that the design is based on proven technology, and offers a clean, economic and safe energy for electricity and high temperature process heat. 2 refs., 4 figs

  16. A study on the design concepts of the PBMR and the GT-MHR

    Energy Technology Data Exchange (ETDEWEB)

    Park, Won Seok; Chang, Jong Hwa; Park, Chang Kue

    2004-05-01

    The major application of the nuclear power in the energy sector has been to produce the electricity. However, a growing concern on the environment and the expected shortage of the fossil energy resources is demanding the expansion of nuclear energy's role in the energy sectors. The High Temperature Gas cooled Reactor (HTGR) has been expected to expand the role of nuclear energy because of its high temperature capability. Especially, the interest on the HTGR has been sharply increased recently related with the production of the hydrogen. About 5 HTGRs had been operated by the end of 1980s. However, all of them had been terminated permanently at the end of 1980s because of their poor system economy and frequent technical troubles. A new concept called MHTGR (Modular High Temperature Gas cooled Reactor) emerged in early of 1990s. Two MHTGR concepts on commercial basis have been developed since then; one is the PBMR (Pebble Bed Modular Reactor) developed by Eskom in South Africa and another is GT-MHR (Gas Turbine Modular High-temperature Reactor) developed by both GA in USA and OKBM in Russia. In this report, the design concepts for the PBMR and GT-MHR were reviewed.

  17. Design features of Advanced Power Reactor (APR) 1400 steam generator

    International Nuclear Information System (INIS)

    Park, Tae-Jung; Park, Jun-Soo; Kim, Moo-Yong

    2004-01-01

    Advanced Power Reactor 1400 (APR 1400) which is to achieve the improvement of the safety and economical efficiency has been developed by Korea Hydro and Nuclear Power Co., Ltd. (KHNP) with the support from industries and research institutes. The steam generator for APR 1400 is an evolutionary type from System 80 + , which is the recirculating U-tube heat exchanger with integral economizer. Compared to the System 80 + steam generator, it is focused on the improved design features, operating and design conditions of APR 1400 steam generator. Especially, from the operation experience of Korean Standard Nuclear Power Plant (KSNP) steam generator, the lessons-learned measures are incorporated to prevent the tube wear caused by flow-induced vibration (FIV). The concepts for the preventive design features against FIV are categorized to two fields; flow distribution and dynamic response characteristics. From the standpoint of flow distribution characteristics, the egg-crate flow distribution plate (EFDP) is installed to prevent the local excessive flow loaded on the most susceptible tube to wear. The parametric study is performed to select the optimum design with the efficient mitigation of local excessive flow. ATHOS3 Mod-01 is used and partly modified to analyze the flow field of the APR 1400 steam generator. In addition, the upper tube bundle support is designed to eliminate the presence of tube with a low natural frequency. Based on the improved upper tube bundle support, the modal analysis is performed and compared with that of System 80 + . Using the results of flow distribution and modal analysis, the two mechanisms of flow-induced vibration are investigated; fluid-elastic instability (FEI) and random turbulence excitation (RTE). (authors)

  18. [Effects of steaming and baking on content of alkaloids in Aconite Lateralis Radix (Fuzi)].

    Science.gov (United States)

    Yang, Chang-lin; Huang, Zhi-fang; Zhang, Yi-han; Liu, Yu-hong; Liu, Yun-huan; Chen, Yan; Yi, Jin-hai

    2014-12-01

    To study the effect of steaming and baking process on contents of alkaloids in Aconite Lateralis Radix (Fuzi), 13 alkaloids were analyzed by UPLC-MS/MS equipped with ESI ion source in MRM mode. In steaming process, the contents of diester-diterpenoid alkaloids decreased rapidly, the contents of monoester-diterpenoid alkaloids firstly increased, reached the peak at 40 min, and then deceased gradually. The contents of aconine alkaloids (mesaconine, aconine and hypaconine) increased all the time during processing, while the contents of fuziline, songorine, karacoline, salsolionl were stable or slightly decreased. In baking process, dynamic variations of alkaloids were different from that in the steaming process. Diester-diterpenoid alkaloids were degraded slightly slower than in steaming process. Monoester-diterpenoid alkaloids, aconine alkaloids and the total alkaloids had been destroyed at different degrees, their contents were significantly lower than the ones in steaming Fuzi at the same processing time. This experiment revealed the dynamic variations of alkaloids in the course of steaming and baking. Two processing methods which can both effectively remove the toxic ingredients and retain the active ingredients are simple and controllable, and are valuable for popularization and application.

  19. Functionality of ovalbumin during Chinese steamed bread-making processing.

    Science.gov (United States)

    Sang, Shangyuan; Zhang, Huang; Xu, Lei; Chen, Yisheng; Xu, Xueming; Jin, Zhengyu; Yang, Na; Wu, Fengfeng; Li, Dandan

    2018-07-01

    Hen egg is commonly used in some cereal-based food, including cakes and bread. Ovalbumin, one of the major components of egg white protein, can affect the performance of the food product. The interaction between ovalbumin and gluten protein and its effect on property of dough and quality of Chinese steamed bread was investigated in this study. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns indicated that ovalbumin was surprisingly not incorporated in glutenins by covalent bond, whereas size-exclusion high-performance liquid chromatography showed that glutenin macropolymer content in glutenins increased slightly. Furthermore, dynamic rheology experiments indicated ovalbumin led to a decrease inG' andG″ of dough. Based on molecular dynamic simulation and SDS-PAGE results, it was inferred that ovalbumin was not hydrolyzed by endopeptidases during dough fermentation and crosslinked to gluten proteins during steaming. Finally, ovalbumin improved maximum dough height (Hm) during dough development and specific volume of Chinese steamed bread. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Station power supply by residual steam of Fugen

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Y.; Kato, H.; Hattori, S. (Power Reactor and Nuclear Fuel Development Corp., Tokyo (Japan))

    1981-09-01

    In the advanced thermal reactor ''Fugen'', when the sudden decrease of load more than 40% occurs due to the failure of power system, the turbine regulating valve is rapidly shut, and the reactor is brought to scrum. However, the operation of turbo-generators is continued with the residual steam in the reactor, and the power for inside the station is supplied for 30 sec by the limiting timer, then the power-generating plant is automatically stopped. The reasons why such design was adopted are to reduce manual operation at the time of emergency, to continue water supply for cooling the reactor and to maintain the water level in the steam drum, and to reduce steam release from the safety valve and the turbine bypass valve. The output-load unbalance relay prevents the everspeed of the turbo-generator when load decreased suddenly, but when the failure of power system is such that recovers automatically in course of time, it does not work. The calculation for estimating the dynamic characteristics at the time of the sole operation within the station is carried out by the analysis code FATRAC. The input conditions for the calculation and the results are reported. Also the dynamic characteristics were actually tested to confirm the set value of the limiting timer and the safe working of turbine and generator trips. The estimated and tested results were almost in agreement.

  1. Development and validation of a CFD-based steam reformer model

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen; Dahlqvist, Mathis; Saksager, Anders

    2006-01-01

    Steam reforming of liquid biofuels (ethanol, bio-diesel etc.) represents a sustainable source of hydrogen for micro Combined Heat and Power (CHP) production as well as Auxiliary Power Units (APUs). In relation to the design of the steam reforming reactor several parameter are important including...... for expensive prototypes. This paper presents an advanced Computational Fluid Dynamics based model of a steam reformer. The model was implemented in the commercial CFD code Fluent through the User Defined Functions interface. The model accounts for the flue gas flow as well as the reformate flow including...... a detailed mechanism for the reforming reactions. Heat exchange between the flue gas and reformate streams through the reformer reactor walls was also included as a conjugate heat transfer process.  From a review of published models for the catalytic steam reforming of ethanol and preliminary predictions...

  2. Large-leak sodium-water reaction analysis for steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Sakano, K; Shindo, Y; Hori, M

    1975-07-01

    The guillotine rupture of 4 tubes is assumed as a design basis regarding the large-leak sodium-water reaction in the system of the MONJU steam generator. Three kinds of analyses were performed with the view to showing the integrity of the steam generator system on the reaction. The first one is the analysis of the initial pressure spike, assuming the initial guillotine rupture of 1 tube. The analysis was performed by utilizing one-dimensional sphere-cylinder model code SWAC-7 and two-dimensional axisymmetric code PISCES 2DL. The second one is the analysis of the secondary peak pressure and its propagation in the system, assuming the instantaneous guillotine rupture of 4 tubes. The third one is the analysis of the dynamic deformation of the steam generator shell. The integrity of the steam generator system was shown by the analyses. (author)

  3. Large-leak sodium-water reaction analysis for steam generators

    International Nuclear Information System (INIS)

    Sakano, K.; Shindo, Y.; Hori, M.

    1975-01-01

    The guillotine rupture of 4 tubes is assumed as a design basis regarding the large-leak sodium-water reaction in the system of the MONJU steam generator. Three kinds of analyses were performed with the view to showing the integrity of the steam generator system on the reaction. The first one is the analysis of the initial pressure spike, assuming the initial guillotine rupture of 1 tube. The analysis was performed by utilizing one-dimensional sphere-cylinder model code SWAC-7 and two-dimensional axisymmetric code PISCES 2DL. The second one is the analysis of the secondary peak pressure and its propagation in the system, assuming the instantaneous guillotine rupture of 4 tubes. The third one is the analysis of the dynamic deformation of the steam generator shell. The integrity of the steam generator system was shown by the analyses. (author)

  4. Two-fluid model with droplet size distribution for condensing steam flows

    International Nuclear Information System (INIS)

    Wróblewski, Włodzimierz; Dykas, Sławomir

    2016-01-01

    The process of energy conversion in the low pressure part of steam turbines may be improved using new and more accurate numerical models. The paper presents a description of a model intended for the condensing steam flow modelling. The model uses a standard condensation model. A physical and a numerical model of the mono- and polydispersed wet-steam flow are presented. The proposed two-fluid model solves separate flow governing equations for the compressible, inviscid vapour and liquid phase. The method of moments with a prescribed function is used for the reconstruction of the water droplet size distribution. The described model is presented for the liquid phase evolution in the flow through the de Laval nozzle. - Highlights: • Computational Fluid Dynamics. • Steam condensation in transonic flows through the Laval nozzles. • In-house CFD code – two-phase flow, two-fluid monodispersed and polydispersed model.

  5. Thermal-hydraulics in recirculating steam generators

    International Nuclear Information System (INIS)

    Carver, M.B.; Carlucci, L.N.; Inch, W.W.R.

    1981-04-01

    This manual describes the THIRST code and its use in computing three-dimensional two-phase flow and heat transfer in a steam generator under steady state operation. The manual is intended primarily to facilitate the application of the code to the analysis of steam generators typical of CANDU nuclear stations. Application to other steam generator designs is also discussed. Details of the assumptions used to formulate the model and to implement the numerical solution are also included

  6. Exergy Steam Drying and Energy Integration

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Prem; Muenter, Claes (Exergy Engineering and Consulting, SE-417 55 Goeteborg (Sweden)). e-mail: verma@exergyse.com

    2008-10-15

    Exergy Steam Drying technology has existed for past 28 years and many new applications have been developed during this period. But during past few years the real benefits have been exploited in connection with bio-fuel production and energy integration. The steam dryer consists of a closed loop system, where the product is conveyed by superheated and pressurised carrier steam. The carrier steam is generated by the water vapours from the product being dried, and is indirectly superheated by another higher temperature energy source such as steam, flue gas, thermal oil etc. Besides the superior heat transfer advantages of using pressurised steam as a drying medium, the energy recovery is efficient and simple as the recovered energy (80-90%) is available in the form of steam. In some applications the product quality is significantly improved. Examples presented in this paper: Bio-Combine for pellets production: Through integration of the Exergy Steam Dryer for wood with a combined heat and power (CHP) plant, together with HP steam turbine, the excess carrier steam can be utilised for district heating and/or electrical power production in a condensing turbine. Bio-ethanol production: Both for first and second generation of ethanol can the Exergy process be integrated for treatment of raw material and by-products. Exergy Steam Dryer can dry the distillers dark grains and solubles (DDGS), wood, bagasse and lignin. Bio-diesel production: Oil containing seeds and fruits can be treated in order to improve both the quality of oil and animal feed protein, thus minimizing further oil processing costs and increasing the sales revenues. Sewage sludge as bio-mass: Municipal sewage sludge can be considered as a renewable bio-fuel. By drying and incineration, the combustion heat value of the sludge is sufficient for the drying process, generation of electrical energy and production of district heat. Keywords; Exergy, bio-fuel, bio-mass, pellets, bio-ethanol, biodiesel, bio

  7. Steam plant for pressurized water reactors

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    This book discusses the research and development organisations and users to highlight those aspects of the steam turbine and associated plant which are particularly related to the PWR system. The contents include: Characteristics of the steam system (including feed train, dump system and safety aspects); overall design aspects of high and half speed turbines; design aspects of the steam generator and seismic considerations; moisture separators and reheaters; feed pumps and their drives; water treatment; safety related valves; operational experience; availability and performance

  8. Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mendler, O J; Takeuchi, K; Young, M Y

    1986-10-01

    The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results.

  9. Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

    International Nuclear Information System (INIS)

    Mendler, O.J.; Takeuchi, K.; Young, M.Y.

    1986-10-01

    The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results

  10. CAREM-25 Steam Generator Stability Analysis

    International Nuclear Information System (INIS)

    Rabiti, A.; Delmastro, D.

    2003-01-01

    In this work the stability of a once-through CAREM-25 steam generator is analyzed.A fix nodes numerical model, that allows the modelling of the liquid, two-phase and superheated steam zones, is implemented.This model was checked against a mobile finite elements model under saturated steam conditions at the channel exit and a good agreement was obtained.Finally the stability of a CAREM steam generator is studied and the range of in let restrictions that a assure the system stability is analyzed

  11. Amazing & extraordinary facts the steam age

    CERN Document Server

    Holland, Julian

    2012-01-01

    Respected transport author Julian Holland delves into the intriguing world of steam in his latest book, which is full of absorbing facts and figures on subjects ranging from Cornish beam engines, steam railway locomotives, road vehicles and ships through to traction engines, steam rollers and electricity generating stations and the people who designed and built them. Helped along the way by the inventive minds of James Watt, Richard Trevithick and George Stephenson, steam became the powerhouse that drove the Industrial Revolution in Britain in the late 18th and 19th centuries.

  12. Method to detect steam generator tube leakage

    International Nuclear Information System (INIS)

    Watabe, Kiyomi

    1994-01-01

    It is important for plant operation to detect minor leakages from the steam generator tube at an early stage, thus, leakage detection has been performed using a condenser air ejector gas monitor and a steam generator blow down monitor, etc. In this study highly-sensitive main steam line monitors have been developed in order to identify leakages in the steam generator more quickly and accurately. The performance of the monitors was verified and the demonstration test at the actual plant was conducted for their intended application to the plants. (author)

  13. Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) System for Long-Haul Rail Application

    Science.gov (United States)

    Chow, Justin Jeff

    Freight movement of goods is the artery for America's economic health. Long-haul rail is the premier mode of transport on a ton-mile basis. Concerns regarding greenhouse gas and criteria pollutant emissions, however, have motivated the creation of annually increasing locomotive emissions standards. Health issues from diesel particulate matter, especially near rail yards, have also been on the rise. These factors and the potential to raise conventional diesel-electric locomotive performance warrants the investigation of using future fuels in a more efficient system for locomotive application. This research evaluates the dynamic performance of a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) Hybrid system operating on hydrogen fuel to power a locomotive over a rail path starting from the Port of Los Angeles and ending in the City of Barstow. Physical constraints, representative locomotive operation logic, and basic design are used from a previous feasibility study and simulations are performed in the MATLAB Simulink environment. In-house controls are adapted to and expanded upon. Results indicate high fuel-to-electricity efficiencies of at least 54% compared to a conventional diesel-electric locomotive efficiency of 35%. Incorporation of properly calibrated feedback and feed-forward controls enables substantial load following of difficult transients that result from train kinematics while maintaining turbomachinery operating requirements and suppressing thermal stresses in the fuel cell stack. The power split between the SOFC and gas turbine is deduced to be a deterministic factor in the balance between capital and operational costs. Using hydrogen results in no emissions if renewable and offers a potential of 24.2% fuel energy savings for the rail industry.

  14. Prediction of an optimum biodiesel-diesel blended fuel for compression ignition engine using GT-power

    International Nuclear Information System (INIS)

    Shah, A.N.; Shah, F.H.; Shahid, E.M.; Gardezi, S.A.R.

    2014-01-01

    This paper describes the development of a turbocharged direct-injection compression ignition (CI) engine model using fluid-dynamic engine simulation codes through a simulating tool known as GT Power. The model was first fueled with diesel, and then with various blends of biodiesel and diesel by allotting suitable parameters to predict an optimum blended fuel. During the optimization, main focus was on the engine performance, combustion, and one of the major regulated gaseous pollutants known as oxides of nitrogen (NOx). The combustion parameters such as Premix Duration (DP), Main Duration (DM), Premix Fraction (FP), Main Exponent (EM) and ignition delay (ID) affect the start of injection (SOI) angle, and thus played significant role in the prediction of optimum blended fuel. The SOI angle ranging from 5.2 to 5.7 degree crank angle (DCA) measured before top dead center (TDC) revealed an optimum biodiesel-diesel blend known as B20 (20% biodiesel and 80% diesel by volume). B20 exhibited the minimum possible NOx emissions, better combustion and acceptable engine performance. Moreover, experiments were performed to validate the simulated results by fueling the engine with B20 fuel and operating it on AC electrical dynamometer. Both the experimental and simulated results were in good agreement revealing maximum deviations of only 3%, 3.4%, 4.2%, and 5.1% for NOx, maximum combustion pressure (MCP), engine brake power (BP), and brake specific fuel consumption (BSFC), respectively. Meanwhile, a positive correlation was found between MCP and NOx showing that both the parameters are higher at lower speeds, relative to higher engine speeds. (author)

  15. Development of Technologies on Innovative-Simplified Nuclear Power Plant Using High-Efficiency Steam Injectors (11) Visualization Study on the Start-Up of the Steam Injector

    International Nuclear Information System (INIS)

    Koji Okamoto; Tadashi Narabayashi; Chikako Iwaki; Shuichi Ohmori; Michitsugu Mori

    2006-01-01

    The Steam Injector is the superior system to pump the fluid without rotating machine. Because the water column is surrounded by the saturated steam, very high heat transfer is also expected with direct condensation. The inside of the Steam Injector is very complicated. To improve the efficiency of the Steam Injector, the water column behavior inside the Injector is visualized using the Dynamic PIV system. Dynamic PIV system consists of the high-speed camera and lasers. In this study, 384 x 180 pixel resolution with 30,000 fps camera is used to visualize the flow. For the illumination CW green laser with 300 mW is applied. To view inside the Injector, relay lens system is set at the Injector wall. Very high speed water column during the starting up of Steam Injector had been clearly visualized with 30,000 fps. The wave velocity on the water column had been analyzed using PIV technique. The instability of the water column is also detected. (authors)

  16. Overview of Hole GT3A: The sheeted dike/gabbro transition

    Science.gov (United States)

    Abe, N.; Harris, M.; Michibayashi, K.; de Obeso, J. C.; Kelemen, P. B.; Takazawa, E.; Teagle, D. A. H.; Coggon, J. A.; Matter, J. M.; Phase I Science Party, T. O. D. P.

    2017-12-01

    Hole GT3A (23.11409 N, 58.21172 E) was drilled by the Oman Drilling Project (OmDP) into Wadi Abdah of the Samail ophiolite, Oman. OmDP is an international collaboration supported by the International Continental Scientifi1c Drilling Program, the Deep Carbon Observatory, NSF, IODP, JAMSTEC, and the European, Japanese, German and Swiss Science Foundations, with in-kind support in Oman from the Ministry of Regional Municipalities and Water Resources, Public Authority of Mining, Sultan Qaboos University, and the German University of Technology. Hole GT3A was diamond cored in February to March 2017 to a total depth of 400 m. The outer surfaces of the cores were imaged and described on site before being curated, boxed and shipped to the IODP drill ship Chikyu, where they underwent comprehensive visual and instrumental analysis. Hole GT3A recovered predominantly sheeted dikes and gabbros and has been sub-divided into 4 igneous groups based on the abundance of gabbro downhole. Group 1 (Upper Sheeted Dike Sequence) occurs from 0 to 111.02 m, group II (Upper Gabbro Sequence) is from 111.02 to 127.89 m, group III (Lower Sheeted Dike Sequence) is between 127.89 to 233.84 m and group IV (Lower Gabbro Sequence) is from 233.84 to 400 m. Group II and IV are both associated with almost equal proportions of dikes to gabbroic lithologies, whereas group I & III have >95% dikes. The sheeted dikes were logged as either basalt (46.9 %) or diabase (26.2 %) depending on the predominant grain size of the dike. Gabbroic lithologies include (most to least abundant) gabbro, oxide gabbro and olivine gabbro. Other lithologies present include diorite (7.5%) and tonalite and trondhjemite (1%). Tonalite and trondhjemite are present as cm-sized dikelets and are found within group II and IV. Gabbroic lithologies generally display a varitextured appearance and are characterised by the co-existence of poikilitic and granular domains. Detailed observations of chilled margins and igneous contacts reveal

  17. Lifetime of superheated steam components

    International Nuclear Information System (INIS)

    Stoklossa, K.H.; Oude-Hengel, H.H.; Kraechter, H.J.

    1974-01-01

    The current evaluation schemes in use for judging the lifetime expectations of superheated steam components are compared with each other. The influence of pressure and temperature fluctuations, the differences in the strength of the wall, and the spread band of constant-strainrates are critically investigated. The distribution of these contributory effects are demonstrated in the hight of numerous measuring results. As an important supplement to these evaluation schemes a newly developed technique is introduced which is designed to calculate failure probabilities. (orig./RW) [de

  18. Strategic management of steam generators

    International Nuclear Information System (INIS)

    Hernalsteen, P.; Berthe, J.

    1991-01-01

    This paper addresses the general approach followed in Belgium for managing any kind of generic defect affecting a Steam Generator tubebundle. This involves the successive steps of: problem detection, dedicated sample monitoring, implementation of preventive methods, development of specific plugging criteria, dedicated 100% inspection, implementation of repair methods, adjusted sample monitoring and repair versus replacement strategy. These steps are illustrated by the particular case of Primary Water Stress Corrosion Cracking in tube roll transitions, which is presently the main problem for two Belgian units Doele-3 and Tihange-2. (author)

  19. Steam generator for nuclear reactors

    International Nuclear Information System (INIS)

    Byerley, W.M.; Bennett, R.R.

    1978-01-01

    In the steam generator, the primary medium is led through a U-shaped tube bundle heating up a secondary medium (feedwater) which flows around the tube bundle via a preheating chamber. In order to optimize heat transfer inside the preheating chamber, the feedwater is separated into a counterflow and a parallel flow with regard to the primary medium by means of partitioning walls and deflectors. The ratio is 70/30%. This way, boiling in the preheater is avoided, i.e. the high LMTD (logaritmic mean temperature difference) is fully utilized. (DG) [de

  20. Impact of steam generator start-up limitations on the performance of a parabolic trough solar power plant

    DEFF Research Database (Denmark)

    Ferruzza, Davide; Topel, Monika; Laumert, Björn

    2018-01-01

    typically start-up and shut down every day, so in order to maximize their profitability, it is necessary to increase their flexibility in transient operation and to initiate power generation as rapidly as possible. Two of the key components are the steam generator and steam turbine and the rates at which...... they can reach operational speed are limited by thermo-mechanical constraints. This paper presents an analysis of the effects of the thermal stress limitations of the steam generator and steam turbine on the power plant start-up, and quantifies their impact on the economy of the system. A dynamic model......-driven and peak-load. The results indicate that for steam generator hot start-ups, a 1.5% increase in peak-load electricity production would be achieved by doubling the maximum allowable heating rate of the evaporator. No useful increase would be achieved by increasing the rates beyond a limit of 7–8 K...

  1. Dynamic modelling and characterisation of a solid oxide fuel cell integrated in a gas turbine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Thorud, Bjoern

    2005-07-01

    This thesis focuses on three main areas within the field of SOFC/GT-technology: 1) Development of a dynamic SOFC/GT model. 2) Model calibration and sensitivity study. 3) Assessment of the dynamic properties of a SOFC/GT power plant. The SOFC/GT model developed in this thesis describes a pressurised tubular Siemens Westinghouse-type SOFC, which is integrated in a gas turbine cycle. The process further includes a plate-fin recuperator for stack air preheating, a prereformer, an anode exhaust gas recycling loop for steam/carbon-ratio control, an afterburner and a shell-tube heat exchanger for air preheating. The fuel cell tube, the recuperator and the shell-tube heat exchanger are spatially distributed models. The SOFC model is further thermally integrated with the prereformer. The compressor and turbine models are based on performance maps as a general representation of the characteristics. In addition, a shaft model which incorporates moment of inertia is included to account for gas turbine transients. The SOFC model is calibrated against experimentally obtained data from a single-cell experiment performed on a Siemens Westinghouse tubular SOFC. The agreement between the model and the experimental results is good. The sensitivity study revealed that the degree of prereforming is of great importance with respect to the axial temperature distribution of the fuel cell. Types of malfunctions are discussed prior to the dynamic behaviour study. The dynamic study of the SOFC/GT process is performed by simulating small and large load changes according to three different strategies; 1) Load change at constant mean fuel cell temperature. 2) Load change at constant turbine inlet temperature. 3) Load change at constant shaft speed. Of these three strategies, the constant mean fuel cell temperature strategy appears to be the most rapid load change method. Furthermore, this strategy implies the lowest degree of thermal cycling, the smoothest fuel cell temperature distribution and

  2. Thermal performances of molten salt steam generator

    International Nuclear Information System (INIS)

    Yuan, Yibo; He, Canming; Lu, Jianfeng; Ding, Jing

    2016-01-01

    Highlights: • Thermal performances of molten salt steam generator were experimentally studied. • Overall heat transfer coefficient reached maximum with optimal molten salt flow rate. • Energy efficiency first rose and then decreased with salt flow rate and temperature. • Optimal molten salt flow rate and temperature existed for good thermal performance. • High inlet water temperature benefited steam generating rate and energy efficiency. - Abstract: Molten salt steam generator is the key technology for thermal energy conversion from high temperature molten salt to steam, and it is used in solar thermal power station and molten salt reactor. A shell and tube type molten salt steam generator was set up, and its thermal performance and heat transfer mechanism were studied. As a coupling heat transfer process, molten salt steam generation is mainly affected by molten salt convective heat transfer and boiling heat transfer, while its energy efficiency is also affected by the heat loss. As molten salt temperature increased, the energy efficiency first rose with the increase of heat flow absorbed by water/steam, and then slightly decreased for large heat loss as the absorbed heat flow still rising. At very high molten salt temperature, the absorbed heat flow decreased as boiling heat transfer coefficient dropping, and then the energy efficiency quickly dropped. As the inlet water temperature increased, the boiling region in the steam generator remarkably expanded, and then the steam generation rate and energy efficiency both rose with the overall heat transfer coefficient increasing. As the molten salt flow rate increased, the wall temperature rose and the boiling heat transfer coefficient first increased and then decreased according to the boiling curve, so the overall heat transfer coefficient first increased and then decreased, and then the steam generation rate and energy efficiency of steam generator both had maxima.

  3. Bio sorption of strontium from aqueous solution by the new strain of bacillus sp. strain GT-83

    International Nuclear Information System (INIS)

    Tajer Mohammad Ghazvini, P.; Ghorbanzadeh Mashkani, S.; Mazaheri, M.

    2009-01-01

    An attempt was made to isolate bacterial strains capable of removing strontium biologically. In this study ten different water samples collected from Neydasht spring in the north of Iran and then the bacterial species were isolated from the water samples. The initial screening of a total of 50 bacterial isolates resulted in selection of one strain.The isolated strain showed a maximum adsorption capacity with 55 milligrams strontium/g dry wt. It was tentatively identified as Bacillus sp. According to the morphological and biochemical properties, and called strain GT-83. Our studies indicated that Bacillus sp. GT-83 is able to grow aerobically in the presence of 50 mM SrCl 2 , but its growth was inhibited at high levels of strontium concentrations. The bio sorption capacity of Bacillus sp. GT-83 depends strongly on the p H solution. Hence the maximum strontium sorption capacity of Bacillus sp. GT-83 was obtained at pah 10, independent of absence or presence of MgCl 2 of different concentrations. Strontium-salt bio sorption studies were also performed at this p H values. The equilibrium bio sorption of strontium was elevated by increasing the strontium concentration, up to 250 milligrams/l for Bacillus sp. GT-83. The maximum bio sorption of strontium was obtained at temperatures in the range of 30-35 d eg C . The Bacillus sp. GT-83 bio sorbed 97 milligrams strontium/g dry wt at 100 milligrams/l initial strontium concentration without MgCl 2 . When MgCl 2 concentration increased to 15%(w/v), these values dropped to 23.6 milligrams strontium/g dry wt at the same conditions. Uptake of strontium within 5 min of incubation was relatively rapid and the absorption continued slowly thereafter

  4. WBP/SIGAME the Brazilian BIG-GT demonstration project actual status and perspectives

    International Nuclear Information System (INIS)

    Carpentier, E.; Silva, A.

    1998-01-01

    Located in the tropics, with the sun shining all year round, and with its vast territory, Brazil may be regarded as having all the basic conditions to develop a modern Biomass for Electricity industry. Those characteristics together with: (a) the necessity of developing new energy resources for electricity production, in the northeast of the country; (b) the results of studies made by various entities, including CHESF; (c) the progress achieved by the BIG-GT technology; (d) the organisation of the Global Environment Facility (GEF); (e) and the support of the Brazilian government, through the Ministry of Science and Technology (MCT), provided the unique opportunity for the implementation of a commercial demonstration of that technology in Brazil. This paper describes the idea, scope, challenges, lessons, and actual status of development of the WBP/SIGAME project. It also highlights some institutional issues, budget figures, and energy prices. (author)

  5. Neutronic evaluation of a fuel block of a GT-MHR using WIMSD5

    International Nuclear Information System (INIS)

    Silva, Clarysson Alberto Mello da; Pereira, Claubia; Costa, Antonella Lombardi; Veloso, Maria Auxiliadora Fortini

    2009-01-01

    The goal is to simulate a representative fuel block of a GT-MHR core to analyze the neutronic parameters behavior due the insertion of Pu isotopes and Minor Actinides (MAs) using shuffling scheme. Initially the fuel block was filled with Driver Fuel (DF), and after burned, these fuels are reprocessed and build the Transmutation Fuel (TF). After some cycles, the fuel block was filled with DF and TF fuels. The DF is a mixture of Pu and Np and the TF is a mix of Pu and MAs. The shuffled scheme was evaluated after each cycle. It was verified that neutronic parameters and isotopic composition reach equilibrium and remain within safety limits when this scheme is used. In addition, there were burnup of MAs. The WIMS code was used in the simulations and the following neutronic parameters were evaluated: infinitive multiplication factor, spectrum hardening and reactivity temperature coefficients. (author)

  6. Management system and potential markets for a HTR-GT plant

    International Nuclear Information System (INIS)

    Crommelin, G.A.K.

    1997-01-01

    This article will discuss some aspects which could be helpful to execute a HTR-GT study successfully: 1. The preferred type of organisation for such a study; in order to achieve a maximum of support in society and industry, a minimum of through life costing and a maximum of through life support. 2. The lead time needed for such studies i.e. the design, component testing, prototype testing, the required efficiency, the type of energy in quantity and quality, financial targets, controllability, maintainability and reliability. 3. The potential markets for the nuclear gasturbine driven energy plants in the low power range. Analyses of the markets will be explained from the user's point of view on why, when and how, for what purpose, in which power range, as well as how many units per application would be required. (author)

  7. Slurry Ice as a Cooling System on 30 GT Fishing Vessel

    Directory of Open Access Journals (Sweden)

    Alam Baheramsyah

    2017-06-01

    Full Text Available Indonesia is the largest archipelago country in the world that has a sea area that is very spacious. Indonesian sea area is 5.8 million square kilometers and a coastline of 95 181 km has huge potential in the fisheries sector. In line with the need to further improve on the quality of the fish catch. One way to preserve fish is to use a slurry of ice. Slurry ice proved more effective preserving fishery products instead of using ice cubes. Ice slurry cooling system was designed and applied to the fishing vessel 30 GT. The cooling system uses a simple vapor compression system consists of five major components consisting of evaporator, condenser, compressor, and two pumps.In designing this system determined the type of refrigerant used in advance which type of refrigerant R-507a. Then do the design or selection of its main components. The design is only done on the evaporator. As for the other major components such as condensers, compressors, and pumps election in accordance with the specification of the power needed. After that dialakukan depiction of each system component. Then subsequently designing the laying of ice slurry cooling system components on a fishing vessel 30 GT.            Through calculations using simple thermodynamic equations obtained cooling load on this system amounted to 32.06 kW. Condenser with a power of 40 kW. Compressor with power 12 kW. Pump with capacity 10 m3 / h. With memepertimbangkan space left on the ship in the ice slurry system design on the main deck of the ship to the efficient use of space on board. The power requirements of the generator vessel increases due to the addition of ice slurry system components therefore do replacement generator into the generator with a power of 100 kW and penambahn fuel tank to 6,000 L.

  8. The testing of a steam-water separating device used for vertical steam generators

    International Nuclear Information System (INIS)

    Ding Xunshen; Cui Baoyuan; Xue Yunkui; Liu Shixun

    1989-01-01

    The air-water screening tests of a steam-water separating device used for vertical steam generators at low pressure are introduced. The article puts emphasis on the qualification test of the steam-water separating device at hot conditions in a high temperature and pressure water test rig. The performance of the comprehensive test of the steam-water separating device indicates that the humidity of the steam at the drier exit is much less than the specified amount of 0.25%

  9. Procedure for generating steam and steam generator for operating said procedure

    International Nuclear Information System (INIS)

    Chlique, Bernard.

    1975-01-01

    This invention concerns the generation of steam by bringing the water to be vaporised into indirect thermal exchange relation with the heating steam which condenses when passing in series, along alternate routes, through bundles of tubes immersed in a vaporising chamber. A number of steam generators working on this principle already exist. The purpose of the invention is to modify the operating method of these steam generators by means of a special disposition making it possible to build a compact unit including an additional bundle of tubes heated by the condensates collected at the outlet of each bundle through which the heating steam passes [fr

  10. Clinical utilisation of the "G.T. MSRS", the rating scale for mixed states: 35 cases report.

    Science.gov (United States)

    Tavormina, Giuseppe

    2015-09-01

    The knowledge of the clinical features of the mixed states and of the symptoms of the "mixity" of mood disorders is crucial: to mis-diagnose or mis-treat patients with these symptoms may increase the suicide risk and make worse the evolution of mood disorders. The rating scale "G.T. MSRS" has been designed to improve the clinical effectiveness of both psychiatrists and GPs by enabling them to make an early "general" diagnosis of mixed states. This study presents some cases in which the "G.T. MSRS" scale has been used, in order to demonstrate its usefullness.

  11. Clinical Utilisation and Usefullness of the Rating Scale of Mixed States, ("Gt-Msrs"): a Multicenter Study.

    Science.gov (United States)

    Tavormina, Giuseppe; Franza, Francesco; Stranieri, Giuseppe; Juli, Luigi; Juli, Maria Rosaria

    2017-09-01

    The rating scale "G.T. MSRS" has been designed to improve the clinical effectiveness of the clinician psychiatrists, by enabling them to make an early "general" diagnosis of mixed states. The knowledge of the clinical features of the mixed states and of the symptoms of the "mixity" of mood disorders is crucial: to mis-diagnose or mis-treat patients with these symptoms may increase the suicide risk and make worse the evolution of mood disorders going to the dysphoric state. This study is the second validation study of the "G.T. MSRS" rating scale, in order to demonstrate its usefullness.

  12. Structural characterization of O- and C-glycosylating variants of the landomycin glycosyltransferase LanGT2.

    Science.gov (United States)

    Tam, Heng Keat; Härle, Johannes; Gerhardt, Stefan; Rohr, Jürgen; Wang, Guojun; Thorson, Jon S; Bigot, Aurélien; Lutterbeck, Monika; Seiche, Wolfgang; Breit, Bernhard; Bechthold, Andreas; Einsle, Oliver

    2015-02-23

    The structures of the O-glycosyltransferase LanGT2 and the engineered, C-C bond-forming variant LanGT2S8Ac show how the replacement of a single loop can change the functionality of the enzyme. Crystal structures of the enzymes in complex with a nonhydrolyzable nucleotide-sugar analogue revealed that there is a conformational transition to create the binding sites for the aglycon substrate. This induced-fit transition was explored by molecular docking experiments with various aglycon substrates. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Linear parameter-varying modeling and control of the steam temperature in a Canadian SCWR

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Peiwei, E-mail: sunpeiwei@mail.xjtu.edu.cn; Zhang, Jianmin; Su, Guanghui

    2017-03-15

    Highlights: • Nonlinearity of Canadian SCWR is analyzed based on step responses and Nyquist plots. • LPV model is derived through Jacobian linearization and curve fitting. • An output feedback H{sub ∞} controller is synthesized for the steam temperature. • The control performance is evaluated by step disturbances and wide range operation. • The controller can stabilize the system and reject the reactor power disturbance. - Abstract: The Canadian direct-cycle Supercritical Water-cooled Reactor (SCWR) is a pressure-tube type SCWR under development in Canada. The dynamics of the steam temperature have a high degree of nonlinearity and are highly sensitive to reactor power disturbances. Traditional gain scheduling control cannot theoretically guarantee stability for all operating regions. The control performance can also be deteriorated when the controllers are switched. In this paper, a linear parameter-varying (LPV) strategy is proposed to solve such problems. Jacobian linearization and curve fitting are applied to derive the LPV model, which is verified using a nonlinear dynamic model and determined to be sufficiently accurate for control studies. An output feedback H{sub ∞} controller is synthesized to stabilize the steam temperature system and reject reactor power disturbances. The LPV steam temperature controller is implemented using a nonlinear dynamic model, and step changes in the setpoints and typical load patterns are carried out in the testing process. It is demonstrated through numerical simulation that the LPV controller not only stabilizes the steam temperature under different disturbances but also efficiently rejects reactor power disturbances and suppresses the steam temperature variation at different power levels. The LPV approach is effective in solving control problems of the steam temperature in the Canadian SCWR.

  14. Steam generator tubing NDE performance

    International Nuclear Information System (INIS)

    Henry, G.; Welty, C.S. Jr.

    1997-01-01

    Steam generator (SG) non-destructive examination (NDE) is a fundamental element in the broader SG in-service inspection (ISI) process, a cornerstone in the management of PWR steam generators. Based on objective performance measures (tube leak forced outages and SG-related capacity factor loss), ISI performance has shown a continually improving trend over the years. Performance of the NDE element is a function of the fundamental capability of the technique, and the ability of the analysis portion of the process in field implementation of the technique. The technology continues to improve in several areas, e.g. system sensitivity, data collection rates, probe/coil design, and data analysis software. With these improvements comes the attendant requirement for qualification of the technique on the damage form(s) to which it will be applied, and for training and qualification of the data analysis element of the ISI process on the field implementation of the technique. The introduction of data transfer via fiber optic line allows for remote data acquisition and analysis, thus improving the efficiency of analysis for a limited pool of data analysts. This paper provides an overview of the current status of SG NDE, and identifies several important issues to be addressed

  15. Control device for steam turbine

    International Nuclear Information System (INIS)

    Hoshi, Hiroyuki.

    1993-01-01

    A power load imbalance detection circuit detects a power load imbalance when a load variation coefficient is large and output-load deviation is great. Then, it self-holds and causes a timer to start counting up and releases the self-holding after the elapse of a certain period of time. Upon load separation caused by system accidents, the power load imbalance detection circuit operates along with the increase of turbine rpm, to operate the control valve abrupt closing circuit and a bypassing value abrupt opening circuit. Then, self-holding of the power load imbalance detection circuit is released and, subsequently, a steam control value and a bypass valve are controlled by a control valve flow rate demand signal and a bypass flow rate demand signal determined by an entire main steam flow rate signal and a speed/load control signal. Accordingly, the turbine rpm is settled to about a rated rpm. This enables to avoid reactor shutdown upon occurrence of load interruption. (I.N.)

  16. Third international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues.

  17. Third international seminar on horizontal steam generators

    International Nuclear Information System (INIS)

    1995-01-01

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues

  18. Containments for consolidated nuclear steam systems

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1978-01-01

    A containment system for a consolidated nuclear steam system incorporating a nuclear core, steam generator and reactor coolant pumps within a single pressure vessel is described which is designed to provide radiation shielding and pressure suppression. Design details, including those for the dry well and wet well of the containment, are given. (UK)

  19. Steam injection : analysis of a typical application.

    NARCIS (Netherlands)

    Penning, F.M.; Lange, de H.C.

    1996-01-01

    A cardboard factory requires steam and electricity, which are produced in its own powerplant. Conventional cogeneration systems cannot cope with the large fluctuations in steam demand, inherent to the cardboard production process, while power demand remains almost constant. For this reason, two

  20. Sintering of nickel steam reforming catalysts

    DEFF Research Database (Denmark)

    Sehested, Jens; Larsen, Niels Wessel; Falsig, Hanne

    2014-01-01

    . In this paper, particle migration and coalescence in nickel steam reforming catalysts is studied. Density functional theory calculations indicate that Ni-OH dominate nickel transport at nickel surfaces in the presence of steam and hydrogen as Ni-OH has the lowest combined energies of formation and diffusion...

  1. Third international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues.

  2. Steam generator leak detection using acoustic method

    International Nuclear Information System (INIS)

    Goluchko, V.V.; Sokolov, B.M.; Bulanov, A.N.

    1982-05-01

    The main requirements to meet by a device for leak detection in sodium - water steam generators are determined. The potentialities of instrumentation designed based on the developed requirements have been tested using a model of a 550 kw steam generator [fr

  3. Steam Reformer With Fibrous Catalytic Combustor

    Science.gov (United States)

    Voecks, Gerald E.

    1987-01-01

    Proposed steam-reforming reactor derives heat from internal combustion on fibrous catalyst. Supplies of fuel and air to combustor controlled to meet demand for heat for steam-reforming reaction. Enables use of less expensive reactor-tube material by limiting temperature to value safe for material yet not so low as to reduce reactor efficiency.

  4. Steam-frothing of milk for coffee

    DEFF Research Database (Denmark)

    Münchow, Morten; Jørgensen, Leif; Amigo Rubio, Jose Manuel

    2015-01-01

    A method for evaluation of the foaming properties of steam-frothed milk, based on image analysis (feature extraction) carried out on a video taken immediately after foam formation, was developed. The method was shown to be able to analyse steam-frothed milk made using a conventional espresso mach...

  5. LMR steam generator blowdown with RETRAN

    International Nuclear Information System (INIS)

    Wei, T.Y.C.

    1985-01-01

    One of the transients being considered in the FSAR Chapter 15 analyses of anticipated LMR transients is the fast blowdown of a steam generator upon inadvertent actuation of the liquid metal/water reaction mitigation system. For the blowdown analysis, a stand-alone steam generator model for the IFR plant was constructed using RETRAN

  6. Water regime of steam power plants

    International Nuclear Information System (INIS)

    Oesz, Janos

    2011-01-01

    The water regime of water-steam thermal power plants (secondary side of pressurized water reactors (PWR); fossil-fired thermal power plants - referred to as steam power plants) has changed in the past 30 years, due to a shift from water chemistry to water regime approach. The article summarizes measures (that have been realised by chemists of NPP Paks) on which the secondary side of NPP Paks has become a high purity water-steam power plant and by which the water chemistry stress corrosion risk of heat transfer tubes in the VVER-440 steam generators was minimized. The measures can also be applied to the water regime of fossil-fired thermal power plants with super- and subcritical steam pressure. Based on the reliability analogue of PWR steam generators, water regime can be defined as the harmony of construction, material(s) and water chemistry, which needs to be provided in not only the steam generators (boiler) but in each heat exchanger of steam power plant: - Construction determines the processes of flow, heat and mass transfer and their local inequalities; - Material(s) determines the minimal rate of general corrosion and the sensitivity for local corrosion damage; - Water chemistry influences the general corrosion of material(s) and the corrosion products transport, as well as the formation of local corrosion environment. (orig.)

  7. Operating experiences with 1 MW steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Sano, A; Kanamori, A; Tsuchiya, T

    1975-07-01

    1 MW steam generator, which was planned as the first stage of steam generator development in Power Reactor and Nuclear Fuel Corp. (PNC) in Japan, is a single-unit, once-through, integrated shell and tube type with multi-helical coil tubes. It was completed in Oarai Engineering Center of PNC in March of 1971, and the various performance tests were carried out up to April, 1972. After the dismantle of the steam generator for structural inspection and material test, it was restored with some improvements. In this second 1 MW steam generator, small leak occurred twice during normal operation. After repairing the failure, the same kind of performance tests as the first steam generator were conducted in order to verify the thermal insulation effect of argon gas in downcomer zone from March to June, 1974. In this paper the above operating experiences were presented including the outline of some performance test results. (author)

  8. Strategic maintenance plan for Cernavoda steam generators

    International Nuclear Information System (INIS)

    Cicerone, T.; Dhar, D.; VandenBerg, J.P.

    2002-01-01

    Steam generators are among the most important pieces of equipment in a nuclear power plant. They are required full time during the plant operation and obviously no redundancy exists. Past experience has shown that those utilities which implemented comprehensive steam generator inspection and maintenance programs and strict water chemistry controls, have had good steam generator performance that supports good overall plant performance. The purpose of this paper is to discuss a strategic Life Management and Operational-monitoring program for the Cernavoda steam generators. The program is first of all to develop a base of expertise for the management of the steam generator condition; and that is to be supported by a program of actions to be accomplished over time to assess their condition, to take measures to avoid degradation and to provide for inspections, cleaning and modifications as necessary. (author)

  9. Circumferential cracking of steam generator tubes

    International Nuclear Information System (INIS)

    Karwoski, K.J.

    1997-04-01

    On April 28, 1995, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 95-03, open-quote Circumferential Cracking of Steam Generator Tubes.close-quote GL 95-03 was issued to obtain information needed to verify licensee compliance with existing regulatory requirements regarding the integrity of steam generator tubes in domestic pressurized-water reactors (PWRs). This report briefly describes the design and function of domestic steam generators and summarizes the staff's assessment of the responses to GL 95-03. The report concludes with several observations related to steam generator operating experience. This report is intended to be representative of significant operating experience pertaining to circumferential cracking of steam generator tubes from April 1995 through December 1996. Operating experience prior to April 1995 is discussed throughout the report, as necessary, for completeness

  10. Maintenance and repair of LMFBR steam generators

    International Nuclear Information System (INIS)

    Verriere, P.; Alanche, J.; Minguet, J.L.

    1984-06-01

    After some general remarks on the French fast neutron system, this paper presents the state of the program for the construction of fast reactor in France. Then, the general design of Super Phenix 1 steam generator components is outlined and, the in-service monitoring systems and protective devices with which they are equiped are briefly described. The methods used, in the event of leakage, for leak location, steam generator inspection, steam generator repair and putting the affected loop back into service, are discussed. There are two main lines of research, relating respectively to the means of water leak detection in sodium and the inspection arrangements that will be used either periodically, or following a sodium-water reaction. Finally, after a brief description of the steam generator, this paper describes the four incidents (leaks) that occurred on the Phenix steam generator in the course of 1982 and 1983, and the subsequent repair operations

  11. A drier unit for steam separators

    International Nuclear Information System (INIS)

    Peyrelongue, J.-P.

    1973-01-01

    Description is given of a drier unit adapted to equip a water separator mounted in a unit for treating a wet steam fed from a high pressure enclosure, so as to dry and contingently superheat said steam prior to injecting same into a turbine low pressure stage. This drier unit is constituted by at least a stack of separating sheets maintained in parallel relationship and at a slight angle with respect to the horizontal so as to allow the water provided by wet steam to flow toward a channel communicating with a manifold, and by means for guiding the steam between the sheets and evenly distributing it. This can be applied to steam turbines in nuclear power stations [fr

  12. Steam generator tube rupture (SGTR) scenarios

    International Nuclear Information System (INIS)

    Auvinen, A.; Jokiniemi, J.K.; Laehde, A.; Routamo, T.; Lundstroem, P.; Tuomisto, H.; Dienstbier, J.; Guentay, S.; Suckow, D.; Dehbi, A.; Slootman, M.; Herranz, L.; Peyres, V.; Polo, J.

    2005-01-01

    The steam generator tube rupture (SGTR) scenarios project was carried out in the EU 5th framework programme in the field of nuclear safety during years 2000-2002. The first objective of the project was to generate a comprehensive database on fission product retention in a steam generator. The second objective was to verify and develop predictive models to support accident management interventions in steam generator tube rupture sequences, which either directly lead to severe accident conditions or are induced by other sequences leading to severe accidents. The models developed for fission product retention were to be included in severe accident codes. In addition, it was shown that existing models for turbulent deposition, which is the dominating deposition mechanism in dry conditions and at high flow rates, contain large uncertainties. The results of the project are applicable to various pressurised water reactors, including vertical steam generators (western PWR) and horizontal steam generators (VVER)

  13. Testing installation for a steam generator

    International Nuclear Information System (INIS)

    Dubourg, M.

    1985-01-01

    The invention proposes a testing installation for a steam generator associated to a boiler, comprising a testing exchanger connected to a feeding circuit in secondary fluid and to a circuit to release the steam produced, and comprising a heating-tube bundle connected to a closed circuit of circulation of a primary coolant at the same temperature and at the pressure than the primary fluid. The heating-tube bundle of the testing exchanger has the same height than the primary bundle of the steam generator and the testing exchanger is at the same level and near the steam generator and is fed by the same secondary fluid such as it is subject to the same operation phases during a long period. The in - vention applies, more particularly, to the steam generators of pressurized water nuclear power plants [fr

  14. Cleanliness criteria to improve steam generator performance

    International Nuclear Information System (INIS)

    Schwarz, T.; Bouecke, R.; Odar, S.

    2005-01-01

    High steam generator performance is a prerequisite for high plant availability and possible life time extension. The major opponent to that is corrosion and fouling of the heating tubes. Such steam generator degradation problems arise from the continuous ingress of non-volatile contaminants, i.e. corrosion products and salt impurities may accumulate in the steam generators. These impurities have their origin in the secondary side systems. The corrosion products generally accumulate in the steam generators and form deposits not only in the flow restricted areas, such as on top of tube sheet and tube support structure, but also build scales on the steam generator heating tubes. In addition, the tube scales in general affect the steam generator thermal performance, which ultimately causes a reduction of power output. The most effective ways of counteracting all these degradation problems, and thus of improving the steam generator performance is to keep them in clean conditions or, if judged necessary, to plan cleaning measures such as mechanical tube sheet lancing or chemical cleaning. This paper presents a methodology how to assess the cleanliness condition of a steam generator by bringing together all available operational and inspection data such as thermal performance and water chemistry data. By means of this all-inclusive approach the cleanliness condition is quantified in terms of a fouling index. The fouling index allows to monitor the condition of a specific steam generator, compare it to other plants and, finally, to serve as criterion for cleaning measures such as chemical cleaning. The application of the cleanliness criteria and the achieved field results with respect to improvements of steam generator performance will be presented. (author)

  15. Simulation benchmark based on THAI-experiment on dissolution of a steam stratification by natural convection

    Energy Technology Data Exchange (ETDEWEB)

    Freitag, M., E-mail: freitag@becker-technologies.com; Schmidt, E.; Gupta, S.; Poss, G.

    2016-04-01

    Highlights: . • We studied the generation and dissolution of steam stratification in natural convection. • We performed a computer code benchmark including blind and open phases. • The dissolution of stratification predicted only qualitatively by LP and CFD models during the blind simulation phase. - Abstract: Locally enriched hydrogen as in stratification may contribute to early containment failure in the course of severe nuclear reactor accidents. During accident sequences steam might accumulate as well to stratifications which can directly influence the distribution and ignitability of hydrogen mixtures in containments. An international code benchmark including Computational Fluid Dynamics (CFD) and Lumped Parameter (LP) codes was conducted in the frame of the German THAI program. Basis for the benchmark was experiment TH24.3 which investigates the dissolution of a steam layer subject to natural convection in the steam-air atmosphere of the THAI vessel. The test provides validation data for the development of CFD and LP models to simulate the atmosphere in the containment of a nuclear reactor installation. In test TH24.3 saturated steam is injected into the upper third of the vessel forming a stratification layer which is then mixed by a superposed thermal convection. In this paper the simulation benchmark will be evaluated in addition to the general discussion about the experimental transient of test TH24.3. Concerning the steam stratification build-up and dilution of the stratification, the numerical programs showed very different results during the blind evaluation phase, but improved noticeable during open simulation phase.

  16. CFD simulations of influence of steam in gasification agent on parameters of UCG process

    Directory of Open Access Journals (Sweden)

    Alina Żogała

    2015-01-01

    Full Text Available Underground coal gasification (UCG is considered to be a perspective and constantly developing technology. Nevertheless it is a very complex and technically difficult process, which results depend on many variables. Mathematical models enable detailed analysis of UCG process – for example – give possibility of prediction of syngas composition depending on applied gasification medium. In practice, mixtures of oxygen, air and steam are the most frequently used as converting agents. Steam is injected to the reactor in order to obtain combustible components. Nevertheless higher concentrations of steam create a problem of reduction of temperature in reactor. This issue of amount of steam in reacting system was analyzed in given paper. Computer simulations were used as test method applied in presented work. Calculations were carried by using Computational Fluid Dynamics (CDF method and Ansys Fluent software. Changes in outlet concentrations of syngas components (CO, CO2, CH4, H2O, H2, in relation with time of process, were presented. Composition of product gas, its heating value and temperature of process were also examined (on outlet of rector in function of content of steam in gasification agent (which was mixture of O2 and H2O. Obtained results indicated a possibility of conduct of stable gasification process (with predictable characteristic of gas. The simulation also demonstrated a possibility of deterioration of conditions in real reactors as a results of applying of too high amounts of steam.

  17. Thermal-hydraulic experiments for the PCHE type steam generator

    International Nuclear Information System (INIS)

    Shin, C. W.; No, H. C.

    2015-01-01

    Printed circuit heat exchanger (PCHE) manufactured by HEATRIC is a compact type of the mini-channel heat exchanger. The PCHE is manufactured by diffusion bonding of the chemically-etched plates, and has high heat transfer rate due to a large surface. Therefore, the size of heat exchanger can be reduced by 1/5 - 1/6 and PCHE can be operated under high pressure, high temperature and multi-phase flow. Under such merits, it is used as heat exchanger with various purposes of gas cycle and water cycle. Recently, it is newly suggested as an application of a steam generator. IRIS of MIT and FASES of KAIST conceptually adopted PCHE as a steam generator. When using boiling condition of micro-channel, flow instability is one of the critical issues. Instability may cause unstable mass flow rate, sudden temperature change and system control failure. However instability tests of micro channels using water are very limited because the previous studies were focused on a single tube or other fluid instead of water. In KAIST, we construct the test facility to study the thermal hydraulics and fluid dynamics of the heat exchanger, especially occurrence of instability. By inducing the pressure drop of inlet water, amplitude of oscillation declined by 90%. Finally, the throttling effect was experimentally confirmed that PCHE could be utilized as a steam generator

  18. Mathematical modeling of a steam generator for sensor fault detection

    International Nuclear Information System (INIS)

    Prock, J.

    1988-01-01

    A dynamic model for a nuclear power plant steam generator (vertical, preheated, U-tube recirculation-type) is formulated as a sixth-order nonlinear system. The model integrates nodal mass and energy balances for the primary water, the U-tube metal and the secondary water and steam. The downcomer flow is determined by a static balance of momentum. The mathematical system is solved using transient input data from the Philippsburg 2 (FRG) nuclear power plant. The results of the calculation are compared with actual measured values. The proposed model provides a low-cost tool for the automatic control and simulation of the steam generating process. The ''parity-space'' algorithm is used to demonstrate the applicability of the mathematical model for sensor fault detection and identification purposes. This technique provides a powerful means of generating temporal analytical redundancy between sensor signals. It demonstrates good detection rates of sensor errors using relatively few steps of scanning time and allows the reconfiguration of faulty signals. (author)

  19. The preliminary results of steam explosion experiments in TROI

    International Nuclear Information System (INIS)

    Song, J.H.; Park, I.K.; Chang, Y.J.; Min, B.T.; Hong, S.W.; Kim, H.D.

    2001-01-01

    Korea Atomic Energy Research Institute (KAERI) launched an intermediate scale steam explosion experiment named 'Test for Real corium Interaction with water (TROI)' using reactor material to investigate the effect of material composition, multi-dimensional melt-water interaction, and hydrogen generation. The melt-water interaction is confined in a pressure vessel with the multi-dimensional fuel and water pool geometry. The cold crucible technology, where the mixture of oxide powder in a water-cooled cage is heated by high frequency induction, is employed. It minimizes unwanted inclusion of impurities during the melting process. The data acquisition system and instrumentations which measure the static and dynamic pressure, temperatures of melt and water are set up. In the first series of tests using several kg of ZrO 2 , melt water interaction is made in a heated water pool at 95 Celsius degrees without triggering. A steam spike pressure at about 10 bar is observed. The morphology of debris shows that there was a mild local steam explosion. The melt water interaction was monitored by video cameras. The UO 2 tests are scheduled around March of 2001, in parallel with the improvements of the design of test facility. (authors)

  20. Flow oscillations on the steam control valve in the middle opening condition. Clarification of the effects of valve body and valve seat by steam experiments

    International Nuclear Information System (INIS)

    Morita, Ryo; Inada, Fumio

    2007-01-01

    A steam control valve might cause vibrations of piping when the valve opening is in a middle condition. For rationalization of maintenance and management of the plant, the valve should be improved, but it is difficult to understand flow characteristics in detail by experiment because flow around the valve is complex 3D structure and becomes supersonic (M>1). Therefore, it is necessary to clarify the cause of the vibrations and to develop the countermeasures by CFD (Computational Fluid Dynamics) technology. In previous researches, we clarified a mechanism of the pressure fluctuations in the middle opening condition and suggested the new valve shape (named 'Extended Valve') that can suppress the pressure fluctuations by air experiments and CFD calculations. Then, we also conducted steam experiments and CFD calculations to understand the differences between air and the steam, and found that the pressure fluctuations in the middle opening condition also occurred in the steam tests and the differences between the air and steam were not remarkable. In this report, to clarify the effects of valve and valve seat shape in steam flow condition, we conduct the steam experiments with various valve and seat shape. As a result, we find the change of the valve seat can decrease the amplitude of pressure fluctuations, but can not quite suppress the pressure fluctuations in the middle opening condition. Then, we apply the 'Extended Valve' to clarify the valve shape effect, and find that the extended valve suppresses the pressure fluctuations in the middle opening condition completely and decreases the pressure amplitude drastically. (author)

  1. Numerical methods on flow instabilities in steam generator

    International Nuclear Information System (INIS)

    Yoshikawa, Ryuji; Hamada, Hirotsugu; Ohshima, Hiroyuki; Yanagisawa, Hideki

    2008-06-01

    The phenomenon of two-phase flow instability is important for the design and operation of many industrial systems and equipment, such as steam generators. The designer's job is to predict the threshold of flow instability in order to design around it or compensate for it. So it is essential to understand the physical phenomena governing such instability and to develop computational tools to model the dynamics of boiling systems. In Japan Atomic Energy Agency, investigations on heat transfer characteristics of steam generator are being performed for the development of Sodium-cooled Fast Breeder Reactor. As one part of the research work, the evaluations of two-phase flow instability in the steam generator are being carried out experimentally and numerically. In this report, the numerical methods were studied for two-phase flow instability analysis in steam generator. For numerical simulation purpose, the special algorithm to calculate inlet flow rate iteratively with inlet pressure and outlet pressure as boundary conditions for the density-wave instability analysis was established. There was no need to solve property derivatives and large matrices, so the spurious numerical instabilities caused by discontinuous property derivatives at boiling boundaries were avoided. Large time-step was possible. The flow instability in single heat transfer tube was successfully simulated with homogeneous equilibrium model by using the present algorithm. Then the drift-flux model including the effects of subcooled boiling and two phase slip was adopted to improve the accuracy. The computer code was developed after selecting the correlations of drift velocity and distribution parameter. The capability of drift flux model together with the present algorithm for simulating density-wave instability in single tube was confirmed. (author)

  2. The Arabidopsis Family GT43 Glycosyltransferases Form Two Functionally Nonredundant Groups Essential for the Elongation of Glucuronoxylan Backbone

    Science.gov (United States)

    There exist four members of family GT43 glycosyltransferases in the Arabidopsis (Arabidopsis thaliana) genome, and mutations of two of them, IRX9 and IRX14, have previously been shown to cause a defect in glucuronoxylan (GX) biosynthesis. However, it is currently unknown whether ...

  3. Første fælles nordiske monitorering af kost, fysisk aktivitet og overvægt

    DEFF Research Database (Denmark)

    Fagt, Sisse; Rasmussen, Lone Banke; Trolle, Ellen

    2012-01-01

    Som en vigtig del af den nordiske handlingsplan for bedre sundhed og livskvalitet gennem kost og fysisk aktivitet har Nordisk Ministerråd besluttet at udvikle og gennemføre en fælles nordisk undersøgelse af kost, fysisk aktivitet og overvægt. Den første monitorering gennemførtes i Norge, Sverige,...

  4. MTP -493G/T gene polymorphism is associated with steatosis in hepatitis C-infected patients

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, E.R.F. [Departamento de Gastroenterologia, LIM-07, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Departamento de Bioquímica, Faculdade de Medicina, Universidade de Pernambuco, Recife, PE (Brazil); Departamento de Gastroenterologia, Faculdade de Medicina, Universidade de Pernambuco, Recife, PE (Brazil); Oliveira, C.P.M.S. [Departamento de Gastroenterologia, LIM-07, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Correa-Giannella, M.L. [Laboratório de Endocrinologia Celular e Molecular, LIM-25, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Stefano, J.T. [Departamento de Gastroenterologia, LIM-07, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Cavaleiro, A.M.; Fortes, M.A.H.Z. [Laboratório de Endocrinologia Celular e Molecular, LIM-25, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Muniz, M.T.C.; Silva, F.S. [Departamento de Bioquímica, Faculdade de Medicina, Universidade de Pernambuco, Recife, PE (Brazil); Pereira, L.M.M.B. [Departamento de Gastroenterologia, Faculdade de Medicina, Universidade de Pernambuco, Recife, PE (Brazil); Instituto do Fígado de Pernambuco, Recife, PE (Brazil); Carrilho, F.J. [Departamento de Gastroenterologia, LIM-07, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil)

    2011-12-09

    The reduction of hepatic microsomal transfer protein (MTP) activity results in fatty liver, worsening hepatic steatosis and fibrosis in chronic hepatitis C (CHC). The G allele of the MTP gene promoter, -493G/T, has been associated with lower transcriptional activity than the T allele. We investigated this association with metabolic and histological variables in patients with CHC. A total of 174 untreated patients with CHC were genotyped for MTP -493G/T by direct sequencing using PCR. All patients were negative for markers of Wilson's disease, hemochromatosis and autoimmune diseases and had current and past daily alcohol intake lower than 100 g/week. The sample distribution was in Hardy-Weinberg equilibrium. Among subjects with genotype 1, 56.8% of the patients with fibrosis grade 3+4 presented at least one G allele versus 34.3% of the patients with fibrosis grade 1+2 (OR = 1.8; 95%CI = 1.3-2.3). Logistic regression analysis with steatosis as the dependent variable identified genotypes GG+GT as independent protective factors against steatosis (OR = 0.4, 95%CI = 0.2-0.8; P = 0.01). The results suggest that the presence of the G allele of MTP -493G/T associated with lower hepatic MTP expression protects against steatosis in our CHC patients.

  5. DNMT3B -579 G>T Promoter Polymorphism and the Risk of Gastric Cancer in the West of Iran.

    Science.gov (United States)

    Ahmadi, Kulsom; Soleimani, Azam; Irani, Shiva; Kiani, Aliasghar; Ghanadi, Kourosh; Noormohamadi, Zahra; Sakinejad, Foroozan

    2018-06-01

    Many studies have suggested that modulation of DNMT3B function caused by single nucleotide polymorphisms of the DNMT3B promoter region may underlie the susceptibility to various cancers such as tumors of the digestive system. The aim of this study was to investigate the effect of -579 G>T polymorphism in the promoter of the DNMT3B gene on risk of gastric cancer in a population from West Iran. We conducted a case-control study in 100 gastric cancer patients and 112 cancer-free controls to assess the correlation between DNMT3B -579 G>T (rs1569686) polymorphism and the risk of gastric cancer. Detection of genotypes of DNMT3B G39179T polymorphism was analyzed by PCR-RFLP. There was no significant difference in the distribution of DNMT3B -579 G>T genotypes between the cases and controls. However, in the stratified analysis by clinicopathological characteristic types, we found that statistically, the risk susceptibility to gastric cancer was significantly associated with tumor grade II and GT/TT genotype of patients, compared to patients having GG genotype, (OR = 5.4737, 95% CI = 1.4746. 20.3184, P = 0.01). Our study suggested that the -579 T allele may increase the relative risk for the progression of clinicopathological characteristic of tumor grade of gastric cancer patients.

  6. Validation of the Actigraph GT3X and ActivPAL Accelerometers for the Assessment of Sedentary Behavior

    Science.gov (United States)

    Kim, Youngdeok; Barry, Vaughn W.; Kang, Minsoo

    2015-01-01

    This study examined (a) the validity of two accelerometers (ActiGraph GT3X [ActiGraph LLC, Pensacola, FL, USA] and activPAL [PAL Technologies Ltd., Glasgow, Scotland]) for the assessment of sedentary behavior; and (b) the variations in assessment accuracy by setting minimum sedentary bout durations against a proxy for direct observation using an…

  7. MTP -493G/T gene polymorphism is associated with steatosis in hepatitis C-infected patients

    International Nuclear Information System (INIS)

    Siqueira, E.R.F.; Oliveira, C.P.M.S.; Correa-Giannella, M.L.; Stefano, J.T.; Cavaleiro, A.M.; Fortes, M.A.H.Z.; Muniz, M.T.C.; Silva, F.S.; Pereira, L.M.M.B.; Carrilho, F.J.

    2011-01-01

    The reduction of hepatic microsomal transfer protein (MTP) activity results in fatty liver, worsening hepatic steatosis and fibrosis in chronic hepatitis C (CHC). The G allele of the MTP gene promoter, -493G/T, has been associated with lower transcriptional activity than the T allele. We investigated this association with metabolic and histological variables in patients with CHC. A total of 174 untreated patients with CHC were genotyped for MTP -493G/T by direct sequencing using PCR. All patients were negative for markers of Wilson's disease, hemochromatosis and autoimmune diseases and had current and past daily alcohol intake lower than 100 g/week. The sample distribution was in Hardy-Weinberg equilibrium. Among subjects with genotype 1, 56.8% of the patients with fibrosis grade 3+4 presented at least one G allele versus 34.3% of the patients with fibrosis grade 1+2 (OR = 1.8; 95%CI = 1.3-2.3). Logistic regression analysis with steatosis as the dependent variable identified genotypes GG+GT as independent protective factors against steatosis (OR = 0.4, 95%CI = 0.2-0.8; P = 0.01). The results suggest that the presence of the G allele of MTP -493G/T associated with lower hepatic MTP expression protects against steatosis in our CHC patients

  8. Steam generator thermal sleeve reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Caton, E.; Askari, A.; Volder, P. [Babcock and Wilcox Canada Ltd., Cambridge, Ontario (Canada)]. E-mail: eecaton@babcock.com

    2003-07-01

    'Full text:' Successful implementation of a physically difficult repair program requires collaboration of the design and construction functions of an organization to ensure that goals are shared and rework or on-the-fly design changes are not required. Furthermore, in a nuclear facility this collaboration results in the optimal safety condition as dose uptake is minimized with a well planned job. The replacement of the degraded thermal sleeves in the Pickering A Steam Generator feedwater nozzles posed this type of problem. The project may be summarized as follows: i) problem analysis, ii) identification of design parameters and limitations, iii) integration of field engineering and design engineering solutions, iv) installation. Integration of the design engineering and field engineering design parameters ensured that the most effective solution was implemented. (author)

  9. Phenomenological modelling of steam explosions

    International Nuclear Information System (INIS)

    Corradini, M.L.; Drumheller, D.S.

    1980-01-01

    During a hypothetical core meltdown accident, an important safety issue to be addressed is the potential for steam explosions. This paper presents analysis and modelling of experimental results. There are four observations that can be drawn from the analysis: (1) vapor explosions are suppressed by noncondensible gases generated by fuel oxidation, by high ambient pressure, and by high water temperatures; (2) these effects appear to be trigger-related in that an explosion can again be induced in some cases by increasing the trigger magnitude; (3) direct fuel liquid-coolant liquid contact can explain small scale fuel fragmentation; (4) heat transfer during the expansion phase of the explosion can reduce the work potential

  10. Steam up over reactor policy

    International Nuclear Information System (INIS)

    Kovan, D.

    1976-01-01

    Britain is once more assessing its nuclear power programme in the light of recent forecasts that there is unlikely to be any growth in the demand for electricity for many years to come. This means that the extra costs of launching a commercially unproven reactor, the Steam Generating Heavy Water Reactor (SGHWR), will be an even greater burden than previously expected, because they would be spread over fewer reactors. Sir John Hill's reported assessment concludes that the present strategy would be the most expensive way of developing Britain's nuclear power programme; and under the circumstances, may not be the best option. The SGHWR programme will certainly be more expensive than either relaunching a programme of advanced gas-cooled reactors (AGRs), or building American designed pressurised water reactors (PWRs). Recent developments of the AGR and PWR's and their advantages in the present position are outlined. (U.K.)

  11. Endoscopic inspection of steam turbines

    International Nuclear Information System (INIS)

    Maliniemi, H.; Muukka, E.

    1990-01-01

    For over ten years, Imatran Voima Oy (IVO) has developed, complementary inspection methods for steam turbine condition monitoring, which can be applied both during operation and shutdown. One important method used periodically during outages is endoscopic inspection. The inspection is based on the method where the internal parts of the turbine is inspected through access borings with endoscope and where the magnified figures of the internal parts is seen on video screen. To improve inspection assurance, an image-processing based pattern recognition method for cracks has been developed for the endoscopic inspection of turbine blades. It is based on the deduction conditions derived from the crack shape. The computer gives an alarm of a crack detection and prints a simulated image of the crack, which is then checked manually

  12. Design of PFBR steam generator

    International Nuclear Information System (INIS)

    Chetal, S.C.; Bhoje, S.B.; Mitra, T.K.; Paranjpe, S.R.; Vaidyanathan, G.

    1990-01-01

    Vertical straight tube with an expansion bend in sodium path is the design selected for the steam generators of 500 MWe Prototype Fast Breeder Reactor (PFBR). There are 4 secondary loops with each loop consisting of 3 modules. With sodium reheat incorporated each module comprises of one evaporator, superheater and reheater. Material of construction is 2.25Cr-1Mo for evaporator and 9Cr-1Mo for superheater and reheater. The tube to tubesheet weld is internal bore butt weld with tubesheet having raised spigot. Aim is to have reliable design with higher plant availability. Design considerations leading to the choice of design features selected are discussed in the paper and a ''reference'' design has been described. (author). 2 figs, 1 tab

  13. Acoustic Leak Detection under Micro and Small Water Steam Leaks into Sodium for a Protection of the SFR Steam Generator

    International Nuclear Information System (INIS)

    Kim, Tae-Joon; Jeong, Ji-Young; Kim, Jong-Man; Kim, Byung-Ho; Hahn, Do-Hee; Yugay, Valeriy S.

    2008-01-01

    The results of an experimental study of water in a sodium leak noise spectrum formation related with a leak noise attenuation and absorption, and at various rates of water into a sodium leak, smaller than 1.0 g/s, are presented. We focused on studying the micro leak dynamics with an increasing rate of water into sodium owing to a self-development from 0.005 till 0.27 g/s. Conditions and ranges for the existence of bubbling and jetting modes in a water steam outflow into circulating sodium through an injector device, for simulating a defect in a wall of a heat-transmitting tube of a sodium water steam generator were determined. On the basis of the experimental leak noise data the simple dependency of an acoustic signal level from the rate of a micro and small leak at different frequency bands is presented to understand the principal analysis for the development of an acoustic leak detection methodology used in a K- 600 steam generator, with the operational experiences for the noise analysis and measurements in BN-600

  14. The effect of steam separataor efficiency on transient following a steam line break

    International Nuclear Information System (INIS)

    Choi, J.H.; Ohn, M.Y.; Lee, N.H.; Hwang, S.T.; Lee, S.K.

    1996-01-01

    Detailed thermalhydraulic simulations for CANDU 6 steam line break inside containment are performed to predict the response of the primary and secondary circuits. The analysis is performed using the thermalhydraulic computer code, CATHENA, with a coupled primary and secondary circuit model. A two-loop representation of the primary and secondary circuits is modelled. The secondary circuit model includes the feedwater line from the deaerator storage tank, multi-node steam generators and the steam line up to the turbine. Two cases were carried out using different assumptions for the efficiency of the steam separators. Case 1 assumes the efficiency of the steam separators becomes zero when the water level in the steam drum increases to the elevation of primary cyclones, or the outlet flow from the steam generator becomes higher than 150 % of normal flow. Case 2 assumes the efficiency becomes zero only when the water level in the steam drum reaches the elevation of primary cyclones. The simulation results show that system responses are sensitive to the assumption for the efficiency of the steam separators and case 1 gives higher discharge energy. Fuel cooling is assured, since primary circuit is cooled down sufficiently by the steam generators for both cases. (author)

  15. Ex-Vessel Steam Explosion Analysis of Central Melt Pour Scenario

    International Nuclear Information System (INIS)

    Ursic, M.; Leskovar, M.

    2008-01-01

    An ex-vessel steam explosion may develop during a severe reactor accident when the reactor vessel fails and the molten core interacts with the coolant in the reactor cavity. At this process part of the corium energy is intensively transferred to water in a very short time scale. The water vaporizes at high pressure and expands, doing work on its surrounding. Although the steam explosion has probably a low probability of occurrence, it is an important nuclear safety issue in case of a severe reactor accident. Namely, the formed very high pressure region induces dynamic loadings on the surrounding structures that may potentially lead to an early release of the radioactive material into the environment. Although the steam explosion events have being studied for several years, the level of the process and consequences understanding is still not adequate. To increase the level of confidence the OECD programme SERENA (Steam Explosion REsolution for Nuclear Applications) was established in 2002. The objectives of the program were to evaluate capabilities of the current generation of the FCI (Fuel-Coolant Interaction) computer codes in predicting the steam explosion induced loads, identifying key FCI phenomena and associated uncertainties impacting the predictability of the steam explosion energetics in the reactor situations and proposing confirmatory research to reduce the uncertainties to acceptable levels for the steam explosion risk assessment. To get a better insight into the most challenging ex-vessel steam explosions, analyses for different locations of the melt release, the cavity water sub-cooling, the primary system pressure overpressure and the triggering time were preformed for a typical pressurized water reactor cavity. The results of some scenarios revealed that significantly higher pressure loads are predicted than obtained in the OECD programme SERENA Phase 1. Among the performed analyses for the central melt pour scenarios, the maximum pressure loads were

  16. Future development of large steam turbines

    International Nuclear Information System (INIS)

    Chevance, A.

    1975-01-01

    An attempt is made to forecast the future of the large steam turbines till 1985. Three parameters affect the development of large turbines: 1) unit output; and a 2000 to 2500MW output may be scheduled; 2) steam quality: and two steam qualities may be considered: medium pressure saturated or slightly overheated steam (light water, heavy water); light enthalpie drop, high pressure steam, high temperature; high enthalpic drop; and 3) the quality of cooling supply. The largest range to be considered might be: open system cooling for sea-sites; humid tower cooling and dry tower cooling. Bi-fluid cooling cycles should be also mentioned. From the study of these influencing factors, it appears that the constructor, for an output of about 2500MW should have at his disposal the followings: two construction technologies for inlet parts and for high and intermediate pressure parts corresponding to both steam qualities; exhaust sections suitable for the different qualities of cooling supply. The two construction technologies with the two steam qualities already exist and involve no major developments. But, the exhaust section sets the question of rotational speed [fr

  17. Steam generating system in LMFBR type reactors

    International Nuclear Information System (INIS)

    Kurosawa, Katsutoshi.

    1984-01-01

    Purpose: To suppress the thermal shock loads to the structures of reactor system and secondary coolant system, for instance, upon plant trip accompanying turbine trip in the steam generation system of LMFBR type reactors. Constitution: Additional feedwater heater is disposed to the pipeway at the inlet of a steam generator in a steam generation system equipped with a closed loop extended from a steam generator by way of a gas-liquid separator, a turbine and a condensator to the steam generator. The separated water at high temperature and high pressure from a gas-liquid separator is heat exchanged with coolants flowing through the closed loop of the steam generation system in non-contact manner and, thereafter, introduced to a water reservoir tank. This can avoid the water to be fed at low temperature as it is to the steam generator, whereby the thermal shock loads to the structures of the reactor system and the secondary coolant system can be suppressed. (Moriyama, K.)

  18. International examples of steam generator replacement

    International Nuclear Information System (INIS)

    Wiechmann, K.

    1993-01-01

    Since 1979-1980 a total of twelve nuclear power plants world-wide have had their steam generators replaced. The replacement of the Combustion steam generators in the Millstone-2 plant in the United States was completed very recently. Steam generator replacement activities are going on at present in four plants. In North Anna, the steam generators have been under replacement since January 1990. In Japan, preparations have been started for Genkai-1. Since January 1992, the two projects in Beznau-1, Switzerland, and Doel-3, Belgium, have bee planned and executed in parallel. Why steam generator replacement? There are a number of defect mechanisms which give rise to the need for early steam generator replacement. One of the main reasons is the use of Inconel-600 as material for the heating tubes. Steam generator heating tubes made of Inconel-600 have been known to exhibit their first defects due to stress corrosion cracking after less than one year of operation. (orig.) [de

  19. An expert system for steam generator maintenance

    International Nuclear Information System (INIS)

    Remond, A.

    1988-01-01

    The tube bundles in PWR steam generators are, by far, the major source of problems whether they are due to primary and secondary side corrosion mechanisms or to tube vibration-induced wear at tube support locations. Because of differences in SG operating, materials, and fabrication processes, the damage may differ from steam generator to steam generator. MPGV, an expert system for steam generator maintenance uses all steam generator data containing data on materials, fabrication processes, inservice inspection, and water chemistry. It has access to operational data for individual steam generators and contains models of possible degradation mechanisms. The objectives of the system are: · Diagnosing the most probable degradation mechanism or mechanisms by reviewing the entire steam generator history. · Identifying the tubes most exposed to future damage and evaluating the urgency of repair by simulating the probable development of the problem in time. · Establishing the appropriate preventive actions such as repair, inspection or other measures and establishing an action schedule. The system is intended for utilities either for individual plants before each inspection outage or any time an incident occurs or for a set of plants through a central MPGV center. (author)

  20. Modeling and simulation of a steam jaketed kettle using FIS

    International Nuclear Information System (INIS)

    Palijo, T. S.; Bhatti, I.

    2006-01-01

    Steam Jacketed Kettles are widely used in the CPI (Chemical Process Industries) for the reaction or processing purposes. The control of the temperature is related to control the rate of reaction. It is more complex to control the all parameters manually, so the controllers are required to design and operate the processes. In order to investigate theoretically the control of a process, it is necessary first to know the dynamic characteristics of the process, which is being controlled. In this paper we first analyze this complex system and its mathematical model. And then we have simulated the dynamics of this system using fuzzy logic approach. In this application Fuzzy logic based process controller has been designed for the steam-Jacketed kettle. Principal design elements used for the process controller are knowledge base, rule base, decision making logic and inference mechanism. The controller uses Fuzzy reasoning that in-fact is an inference system that derives conclusion from a set of Fuzzy IF...THEN rules, as well as known facts about the system. Simulation results obtained using FIS (Fuzzy Inference System) show that fuzzy logic based controller provided improved control of this dynamic process control system. (author)

  1. Experimental modeling of flow-induced vibration of multi-span U-tubes in a CANDU steam generator

    International Nuclear Information System (INIS)

    Mohany, A.; Feenstra, P.; Janzen, V.P.; Richard, R.

    2009-01-01

    Flow-induced vibration of the tubes in a nuclear steam generator is a concern for designers who are trying to increase the life span of these units. The dominant excitation mechanisms are fluidelastic instability and random turbulence excitation. The outermost U-bend region of the tubes is of greatest concern because the flow is almost perpendicular to the tube axis and the unsupported span is relatively long. The support system in this region must be well designed in order to minimize fretting wear of the tubes at the support locations. Much of the previous testing was conducted on straight single-span or cantilevered tubes in cross-flow. However, the dynamic response of steam generator multi-span U-tubes with clearance supports is expected to be different. Accurate modeling of the tube dynamics is important to properly simulate the dynamic interaction of the tube and supports. This paper describes a test program that was developed to measure the dynamic response of a bundle of steam generator U-tubes with Anti-Vibration Bar (AVB) supports, subjected to Freon two-phase cross-flow. The tube bundle has similar geometrical conditions to those expected for future CANDU steam generators. Future steam generators will be larger than previous CANDU steam generators, nearly twice the heat transfer area, with significant changes in process conditions in the U-bend region, such as increased steam quality and a broader range of flow velocities. This test program was initiated at AECL to demonstrate that the tube support design for future CANDU steam generators will meet the stringent requirements associated with a 60 year design life. The main objective of the tests is to address the issue of in-plane and out-of-plane fluidelastic instability and random turbulent excitation of a U-tube bundle with Anti-Vibration Bar (AVB) supports. Details of the test rig, measurement techniques and preliminary instrumentation results are described in the paper. (author)

  2. Present activity of the feasibility study of HTGR-GT system

    International Nuclear Information System (INIS)

    Muto, Y.; Miyamoto, Y.; Shiozawa, S.

    2001-01-01

    In JAERI a feasibility study of the High Temperature Gas-cooled Reactor-Gas Turbine (HTGR-GT) system has been carried out since January, 1997 as an assigned work by the Science and Technology Agency. The study aims at obtaining a promising concept of HTGR-GT system that yields a high thermal efficiency and at the same time is economically competitive. Designs of a few candidate systems will be undertaken and their power generation costs will be evaluated in parallel with design works, some experimental works such as the fabrication of a plate-fin type heat exchanger core and material tests will be carried out. The study will be continued till 2000 fiscal year. In 1997 fiscal year, a preliminary design of a direct cycle plant of 600 MWt was developed. A reactor inlet gas temperature of 460 deg. C, a reactor outlet gas temperature of 850 deg. C and a helium gas pressure of 6MPa were selected. Some advanced technologies were adopted such as a monolithic fuel compact and a control rod sheath made of carbon/carbon composite material. They were very effective to enhance the heat transfer of fuel and to reduce the core bypass flow. As a result, a power density of 6MW/m 3 and the maximum burnup of 10 5 MWD/ton were achieved. A single-shaft horizontal turbomachine of 3600 rpm was selected to ease the mechanical design of the rotor supported by magnetic bearings. The turbine, two compressors, a generator and six units of intercooler were placed in a turbine vessel, Plate-fin type recuperator and precooler are installed in a vertical heat exchanger vessel. By this design, a net thermal efficiency of 45.7% is expected to be achieved. To develop a high performance plate-fin recuperator, a core model of W200 mm x L200 mm x H200 mm with small fin size of 1.15 mm height was fabricated and as a result of tests, leak tightness, component strength and bonding appearance were found to be satisfactory. In 1998 fiscal year, a design of a direct cycle plant of 300 MWt is undertaken. The

  3. Failure analysis of retired steam generator tubings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Pyo; Kim, J. S.; Hwang, S. S. and others

    2005-04-15

    Degradation of steam generator leads to forced outage and extension of outage, which causes increase in repair cost, cost of purchasing replacement power and radiation exposure of workers. Steam generator tube rupture incident occurred in Uljin 4 in 2002, which made public sensitive to nuclear power plant. To keep nuclear energy as a main energy source, integrity of steam generator should be demonstrated. Quantitative relationship between ECT(eddy current test) signal and crack size is needed in assesment of integrity of steam generator in pressurized water reactor. However, it is not fully established for application in industry. Retired steam generator of Kori 1 has many kinds of crack such as circumferential and axial primary water stress corrosion crack and outer diameter stress corrosion crack(ODSCC). So, it can be used in qualifying and improving ECT technology and in condition monitoring assesment for crack detected in ISI(in service inspection). In addition, examination of pulled tube of Kori 1 retired steam generator will give information about effectiveness of non welded sleeving technology which was employed to repair defect tubes and remedial action which was applied to mitigate ODSCC. In this project, hardware such as semi hot lab. for pulled tube examination and modification transportation cask for pulled tube and software such as procedure of transportation of radioactive steam generator tube and non-destructive and destructive examination of pulled tube were established. Non-destructive and destructive examination of pulled tubes from Kori 1 retired steam generator were performed in semi hot lab. Remedial actions applied to Kori 1 retired steam generator, PWSCC trend and bulk water chemistry and crevice chemistry in Kori 1 were evaluated. Electrochemical decontamination technology for pulled tube was developed to reduce radiation exposure and enhance effectiveness of pulled tube examination. Multiparameter algorithm developed at ANL, USA was

  4. Non linear identification applied to PWR steam generators

    International Nuclear Information System (INIS)

    Poncet, B.

    1982-11-01

    For the precise industrial purpose of PWR nuclear power plant steam generator water level control, a natural method is developed where classical techniques seem not to be efficient enough. From this essentially non-linear practical problem, an input-output identification of dynamic systems is proposed. Through Homodynamic Systems, characterized by a regularity property which can be found in most industrial processes with balance set, state form realizations are built, which resolve the exact joining of local dynamic behaviors, in both discrete and continuous time cases, avoiding any load parameter. Specifically non-linear modelling analytical means, which have no influence on local joined behaviors, are also pointed out. Non-linear autoregressive realizations allow us to perform indirect adaptive control under constraint of an admissible given dynamic family [fr

  5. An exergoeconomic investigation of waste heat recovery from the Gas Turbine-Modular Helium Reactor (GT-MHR) employing an ammonia–water power/cooling cycle

    International Nuclear Information System (INIS)

    Zare, V.; Mahmoudi, S.M.S.; Yari, M.

    2013-01-01

    A detailed exergoeconomic analysis is performed for a combined cycle in which the waste heat from the Gas Turbine-Modular Helium Reactor (GT-MHR) is recovered by an ammonia–water power/cooling cogeneration system. Parametric investigations are conducted to evaluate the effects of decision variables on the performances of the GT-MHR and combined cycles. The performances of these cycles are then optimized from the viewpoints of first law, second law and exergoeconomics. It is found that, combining the GT-MHR with ammonia–water cycle not only enhances the first and second law efficiencies of the GT-MHR, but also it improves the cycle performance from the exergoeconomic perspective. The results show that, when the optimization is based on the exergoeconomics, the unit cost of products is reduced by 5.4% in combining the two mentioned cycles. This is achieved with a just about 1% increase in total investment cost rate since the helium mass flow in the combined cycle is lower than that in the GT-MHR alone. - Highlights: • Application of exergetic cost theory to the combined GT-MHR/ammonia–water cycle. • Enhanced exergoeconomic performance for the combined cycle compared to the GT-MHR. • Comparable investment costs for the combined cycle and the GT-MHR alone

  6. Selective hydrogenation processes in steam cracking

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M.; Schroeter, M.K.; Hinrichs, M.; Makarczyk, P. [BASF SE, Ludwigshafen (Germany)

    2010-12-30

    Hydrogen is the key elixir used to trim the quality of olefinic and aromatic product slates from steam crackers. Being co-produced in excess amounts in the thermal cracking process a small part of the hydrogen is consumed in the ''cold part'' of a steam cracker to selectively hydrogenate unwanted, unsaturated hydrocarbons. The compositions of the various steam cracker product streams are adjusted by these processes to the outlet specifications. This presentation gives an overview over state-of-art selective hydrogenation technologies available from BASF for these processes. (Published in summary form only) (orig.)

  7. High speed drying of saturated steam

    International Nuclear Information System (INIS)

    Marty, C.; Peyrelongue, J.P.

    1993-01-01

    This paper describes the development of the drying process for the saturated steam used in the PWR nuclear plant turbines in order to prevent negative effects of water on turbine efficiency, maintenance costs and equipment lifetime. The high speed drying concept is based on rotating the incoming saturated steam in order to separate water which is more denser than the steam; the water film is then extracted through an annular slot. A multicellular modular equipment has been tested. Applications on high and low pressure extraction of various PWR plants are described (Bugey, Loviisa)

  8. Steam Generator Inspection Planning Expert System

    International Nuclear Information System (INIS)

    Rzasa, P.

    1987-01-01

    Applying Artificial Intelligence technology to steam generator non-destructive examination (NDE) can help identify high risk locations in steam generators and can aid in preparing technical specification compliant eddy current test (ECT) programs. A steam Generator Inspection Planning Expert System has been developed which can assist NDE or utility personnel in planning ECT programs. This system represents and processes its information using an object oriented declarative knowledge base, heuristic rules, and symbolic information processing, three artificial intelligence based techniques incorporated in the design. The output of the system is an automated generation of ECT programs. Used in an outage inspection, this system significantly reduced planning time

  9. CFD Analysis of Random Turbulent Flow Load in Steam Generator of APR1400 Under Normal Operation Condition

    International Nuclear Information System (INIS)

    Lim, Sang Gyu; You, Sung Chang; Kim, Han Gon

    2011-01-01

    Regulatory guide 1.20 revision 3 of the Nuclear Regulatory Committee (NRC) modifies guidance for vibration assessments of reactor internals and steam generator internals. The new guidance requires applicants to provide a preliminary analysis and evaluation of the design and performance of a facility, including the safety margins of during normal operation and transient conditions anticipated during the life of the facility. Especially, revision 3 require rigorous assessments of adverse flow effects in the steam dryer cased by flow-excited acoustic and structural resonances such as the abnormality from power-uprated BWR cases. For two nearly identical nuclear power plants, the steam system of one BWR plant experienced failure of steam dryers and the main steam system components when steam flow was increased by 16 percent for extended power uprate (EPU). The mechanisms of those failures have revealed that a small adverse flow changing from the prototype condition induced severe flow-excited acoustic and structural resonances, leading to structural failures. In accordance with the historical background, therefore, potential adverse flow effects should be evaluated rigorously for steam generator internals in both BWR and Pressurized Water Reactor (PWR). The Advanced Power Reactor 1400 (APR1400), an evolutionary light water reactor, increased the power by 7.7 percent from the design of the 'Valid Prototype', System80+. Thus, reliable evaluations of potential adverse flow effects on the steam generator of APR1400 are necessary according to the regulatory guide. This paper is part of the computational fluid dynamics (CFD) analysis results for evaluation of the adverse flow effect for the steam generator internals of APR1400, including a series of sensitivity analyses to enhance the reliability of CFD analysis and an estimation the effect of flow loads on the internals of the steam generator under normal operation conditions

  10. The casebook of technical presentation on a steam generator

    International Nuclear Information System (INIS)

    1986-05-01

    This casebook consists of seven presentations, which are measures and experience of maintenance of water quality in PWR generator, corrosion in steam generator, safely evaluation by management and closing in steam generator, testing of eddy current in steam generator, unsettled problems of safety in steam generator and maintenance of water quality in PWR generator.

  11. 46 CFR 61.15-5 - Steam piping.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main boiler...

  12. 7 CFR 160.8 - Steam distilled wood turpentine.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8... STANDARDS FOR NAVAL STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind of spirits of turpentine obtained by steam distillation from...

  13. 49 CFR 229.105 - Steam generator number.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam generator number. 229.105 Section 229.105..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.105 Steam generator number. An identification number shall be marked on the steam generator's...

  14. Non-polluting steam generators with fluidized-bed furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Brandes, H [Deutsche Babcock A.G., Oberhausen (Germany, F.R.)

    1979-07-01

    The author reports on a 35 MW steam generator with hard coal fluidized-bed furnace a planned 35 MW steam generator with flotation-dirt fluidized-bed furnace, and on planned steam generators for fluidized-bed firing of hard coal up to a steam power of about 200 MW.

  15. Fundamentals of gas dynamics

    CERN Document Server

    Babu, V

    2014-01-01

    Fundamentals of Gas Dynamics, Second Edition isa comprehensively updated new edition and now includes a chapter on the gas dynamics of steam. It covers the fundamental concepts and governing equations of different flows, and includes end of chapter exercises based on the practical applications. A number of useful tables on the thermodynamic properties of steam are also included.Fundamentals of Gas Dynamics, Second Edition begins with an introduction to compressible and incompressible flows before covering the fundamentals of one dimensional flows and normal shock wav

  16. Efficiency enhancement of GT-MHRs applied on ship propulsion plants

    Energy Technology Data Exchange (ETDEWEB)

    Ferreiro Garcia, Ramon, E-mail: ferreiro@udc.es [Dept. Industrial Engineering, University of A Coruna, ETSNM, C/Paseo de Ronda, 51, 15011 A Coruna (Spain); Carril, Jose Carbia; Catoira, Alberto DeMiguel; Romero Gomez, Javier [Dept. Energy and Propulsion, University of A Coruna ETSNM, C/Paseo de Ronda, 51, 15011 A Coruna (Spain)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Efficient ship propulsion system powered by HTRs. Black-Right-Pointing-Pointer A conventional Rankine cycle renders high efficiency. Black-Right-Pointing-Pointer The intermediate heat exchanger isolates the nuclear reactor from the process heat application. Black-Right-Pointing-Pointer An intermediate heat exchanger allows the system to be built to non-nuclear standards. - Abstract: High temperature reactors including gas cooled fast reactors and gas turbine modular helium reactors (GT-MHR) may operate as electric power suppliers to be applied on ship propulsion plants. In such propulsion systems performance enhancement can be achieved at effective cost under safety conditions using alternative cycles to the conventional Brayton cycle. Mentioned improvements concern the implementation of an ultra supercritical Rankine cycle, in which water is used as working fluid. The proposed study is carried out in order to achieve performance enhancement on the basis of turbine temperature increasing. The helium cooled high temperature reactor supplies thermal energy to the Rankine cycle via an intermediate heat exchanger (IHE) under safety conditions. The results of the study show that the efficiency of the propulsion plant using a multi-reheat Rankine cycle is significantly improved (from actual 48% to more than 55%) while keeping safety standards.

  17. Benchmark calculation for GT-MHR using HELIOS/MASTER code package and MCNP

    International Nuclear Information System (INIS)

    Lee, Kyung Hoon; Kim, Kang Seog; Noh, Jae Man; Song, Jae Seung; Zee, Sung Quun

    2005-01-01

    The latest research associated with the very high temperature gas-cooled reactor (VHTR) is focused on the verification of a system performance and safety under operating conditions for the VHTRs. As a part of those, an international gas-cooled reactor program initiated by IAEA is going on. The key objectives of this program are the validation of analytical computer codes and the evaluation of benchmark models for the projected and actual VHTRs. New reactor physics analysis procedure for the prismatic VHTR is under development by adopting the conventional two-step procedure. In this procedure, a few group constants are generated through the transport lattice calculations using the HELIOS code, and the core physics analysis is performed by the 3-dimensional nodal diffusion code MASTER. We evaluated the performance of the HELIOS/MASTER code package through the benchmark calculations related to the GT-MHR (Gas Turbine-Modular Helium Reactor) to dispose weapon plutonium. In parallel, MCNP is employed as a reference code to verify the results of the HELIOS/MASTER procedure

  18. Evolution of the Power Conversion Unit Design of the GT-MHR

    International Nuclear Information System (INIS)

    Baxi, C.B.; Perez, E.; Shenoy, A.; Kostin, V.I.; Kodochigov, N.G.; Vasyaev, A.V.; Belov, S.E.; Golovko, V.F.

    2006-01-01

    General Atomics in the USA and Experimental Design Bureau of Machine Building (OKBM) in the Russian Federation are jointly developing a gas turbine modular helium reactor (GT-MHR). The 600 MW(t) reactor is cooled by helium at a pressure of 7 MPa. The power conversion unit (PCU) uses the reactor outlet temperature of 850 deg C in a direct Brayton cycle to achieve an efficiency of about 48%. The PCU consists of a gas turbine, a recuperator, a pre-cooler, a low-pressure compressor, an inter-cooler, and a high-pressure compressor. The turbo machine (TM), including the generator, is mounted on a single vertical shaft. The TM rotates at a speed of 4400 rpm. The asynchronous generator is connected to the turbine by a flexible coupling. The required grid frequency is achieved by a converter. All PCU components are enclosed in a single vessel. TM uses radial and axial electromagnetic bearings (EMB) for support. Catcher bearings (CB) are provided as redundant support for the TM rotor in case of EMBs failure. These design features were determined after a comprehensive study carried out over the last 10 years. This paper describes the evolution of the current PCU design and justification for the choices. (authors)

  19. Full load synthesis/design optimization of a hybrid SOFC-GT power plant

    International Nuclear Information System (INIS)

    Calise, F.; Dentice d' Accadia, M.; Vanoli, L.; Spakovsky, Michael R. von

    2007-01-01

    In this paper, the optimization of a hybrid solid oxide fuel cell-gas turbine (SOFC-GT) power plant is presented. The plant layout is based on an internal reforming SOFC stack; it also consists of a radial gas turbine, centrifugal compressors and plate-fin heat exchangers. In the first part of the paper, the bulk-flow model used to simulate the plant is presented. In the second part, a thermoeconomic model is developed by introducing capital cost functions. The whole plant is first simulated for a fixed configuration of the most important synthesis/design (S/D) parameters in order to establish a reference design configuration. Next a S/D optimization of the plant is carried out using a traditional single-level approach, based on a genetic algorithm. The optimization determined a set of S/D decision variable values with a capital cost significantly lower than that of the reference design, even though the net electrical efficiency for the optimal configuration was very close to that of the initial one. Furthermore, the optimization procedure dramatically reduced the SOFC active area and the compact heat exchanger areas

  20. Gabbroic lithologies of the dike-gabbro transition, Hole GT3A, Oman Drilling Project

    Science.gov (United States)

    Jesus, A. P. M.; Koepke, J.; Morishita, T.; Beinlich, A.; Johnson, K. T. M.; Greenberger, R. N.; Harris, M.; Michibayashi, K.; de Obeso, J. C.

    2017-12-01

    Hole GT3A intersects 400 m of oceanic crust providing unique insight into the dike-gabbro transition and the variability of the high level gabbros in the Samail ophiolite. Olivine gabbro and olivine bearing gabbro occur exclusively within the Upper Gabbro Sequence (16 % thickness; 111.02 m - 127.89 m) whereas oxide gabbro and disseminated oxide gabbro represent ca 5 % of the Lower Gabbro Sequence (233.84 m - 398.21 m). Gabbro with less than 1 vol. % olivine and oxide is the most common lithology in both Gabbro Sequences (10-13 %). Most gabbroic rocks were classified as "varitextured" due to textural and grain size macroscopic variations forming irregular domains/patches. Varitextured gabbros are medium-grained (1-5 mm), with seriate grain size distribution and subophitic/poikilitic to granular textural domains. Poikilitic domains comprise clinopyroxene with plagioclase chadacrysts, whereas in granular domains plagioclase interstices are filled by green-brown magmatic hornblende; plagioclase is zoned in both domains. Olivine (bearing) gabbros have 4-8 mm skeletal olivine pseudomorphs with roundish inclusions of chromite and plagioclase. Oxide (disseminated) gabbros comprise variable amounts of plagioclase, clinopyroxene, Oman paleo ridge.

  1. Afetividade, ensino e aprendizagem: um estudo no GT20 da ANPEd

    Directory of Open Access Journals (Sweden)

    Elvira Cristina Martins Tassoni

    Full Text Available Este artigo traz um levantamento bibliográfico dos trabalhos apresentados no GT20 - Psicologia da Educação da ANPEd (Associação Nacional de Pós-Graduação e Pesquisa em Educação no período de 2000 a 2010. O objetivo foi rastrear as produções científicas mais recentes que discutem a afetividade e sua relação com os processos de ensino e aprendizagem. Apresenta as perspectivas teóricas em que os estudos sobre a afetividade foram abordados e em que medida tais estudos discutem as influências entre os aspectos afetivos e os processos de ensino e aprendizagem. Os trabalhos foram selecionados segundo os procedimentos metodológicos da análise de conteúdo fundamentada em Bardin (1977. Os resultados permitiram a construção de um panorama a respeito dos estudos sobre afetividade, apontando tendências, períodos em que as discussões sobre o tema foram mais intensas e, sobretudo, demonstrando que tal temática vem marcando presença constante nas discussões das Reuniões Anuais da ANPEd.

  2. Free Moisture in GT-73 Resin Waste Generated from the Effluent Treatment Facility

    International Nuclear Information System (INIS)

    Kaplan, D.I.

    2002-01-01

    Solid Waste Division is presently evaluating whether to transfer spent resin generated from the Effluent Treatment Facility (ETF) to the Nevada Test Site (NTS). One of the criteria for the waste to be accepted at the NTS is that the waste must not contain more than 1 vol-percent free liquid. This criterion reduces the amount of liquid, a primary vector for subsurface contaminant migration (along with colloids), introduced into the repository. This criterion also serves to reduce the chance of an accidental spill during transport of the waste to the NTS. On December 15, 1997, a shipment from Fernald to the NTS leaked some liquid waste onto a highway in Kingman, Arizona, resulting in a Type B Accident Investigation. The direct cause of the leak was attributed to broken welds related to the use of substandard containers. The overall objective of this study was to provide guidance as to whether the spent GT-73 resin would meet the free moisture WAC set by the NTS

  3. Expression of transgenes targeted to the Gt(ROSA26Sor locus is orientation dependent.

    Directory of Open Access Journals (Sweden)

    Douglas Strathdee

    2006-12-01

    Full Text Available Targeting transgenes to a chosen location in the genome has a number of advantages. A single copy of the DNA construct can be inserted by targeting into regions of chromatin that allow the desired developmental and tissue-specific expression of the transgene.In order to develop a reliable system for reproducibly expressing transgenes it was decided to insert constructs at the Gt(ROSA26Sor locus. A cytomegalovirus (CMV promoter was used to drive expression of the Tetracycline (tet transcriptional activator, rtTA2(s-M2, and test the effectiveness of using the ROSA26 locus to allow transgene expression. The tet operator construct was inserted into one allele of ROSA26 and a tet responder construct controlling expression of EGFP was inserted into the other allele.Expression of the targeted transgenes was shown to be affected by both the presence of selectable marker cassettes and by the orientation of the transgenes with respect to the endogenous ROSA26 promoter. These results suggest that transcriptional interference from the endogenous gene promoter or from promoters in the selectable marker cassettes may be affecting transgene expression at the locus. Additionally we have been able to determine the optimal orientation for transgene expression at the ROSA26 locus.

  4. Drying system for steam generators, particularly for steam generators of nuclear power stations

    International Nuclear Information System (INIS)

    Lavalerie, Claude; Borrel, Christian.

    1982-01-01

    A drying system is described which allows for modular construction and which provides a significant available exchange area in a reduced volume. All the drying elements are identical and are distributed according to a ternay circular symmetry and are placed radially and associated to steam guiding facilities which alternately provide around the axis of revolution an output volume of dry steam from one element and an input volume of wet steam in the following element [fr

  5. An Improved Steam Injection Model with the Consideration of Steam Override

    Directory of Open Access Journals (Sweden)

    He Congge

    2017-01-01

    Full Text Available The great difference in density between steam and liquid during wet steam injection always results in steam override, that is, steam gathers on the top of the pay zone. In this article, the equation for steam override coefficient was firstly established based on van Lookeren’s steam override theory and then radius of steam zone and hot fluid zone were derived according to a more realistic temperature distribution and an energy balance in the pay zone. On this basis, the equation for the reservoir heat efficiency with the consideration of steam override was developed. Next, predicted results of the new model were compared with these of another analytical model and CMG STARS (a mature commercial reservoir numerical simulator to verify the accuracy of the new mathematical model. Finally, based on the validated model, we analyzed the effects of injection rate, steam quality and reservoir thickness on the reservoir heat efficiency. The results show that the new model can be simplified to the classic model (Marx-Langenheim model under the condition of the steam override being not taken into account, which means the Marx-Langenheim model is corresponding to a special case of this new model. The new model is much closer to the actual situation compared to the Marx-Langenheim model because of considering steam override. Moreover, with the help of the new model, it is found that the reservoir heat efficiency is not much affected by injection rate and steam quality but significantly influenced by reservoir thickness, and to ensure that the reservoir can be heated effectively, the reservoir thickness should not be too small.

  6. Pressure drop, steam content and turbulent cross exchange in water/steam flows

    International Nuclear Information System (INIS)

    Teichel, H.

    1978-01-01

    For describing the behaviour of two-phase flows of water and steam with the help of calculating patterns, a number of empirical correlations are required. - In this article, correlations for the friction pressure drop in water/steam flows are compared, as well as for the steam mass and the volumetric steam content with each other and with the test results on simple geometries. As the mutual effect between cooling chanels plays an important part at the longitudinal flow through bar bundles, the appertaining equations are evaluated, in addition. (orig.) 891 HP [de

  7. Wavelet network controller for nuclear steam generators

    International Nuclear Information System (INIS)

    Habibiyan, H; Sayadian, A; Ghafoori-Fard, H

    2005-01-01

    Poor control of steam generator water level is the main cause of unexpected shutdowns in nuclear power plants. Particularly at low powers, it is a difficult task due to shrink and swell phenomena and flow measurement errors. In addition, the steam generator is a highly complex, nonlinear and time-varying system and its parameters vary with operating conditions. Therefore, it seems that design of a suitable controller is a necessary step to enhance plant availability factor. The purpose of this paper is to design, analyze and evaluate a water level controller for U-tube steam generators using wavelet neural networks. Computer simulations show that the proposed controller improves transient response of steam generator water level and demonstrate its superiority to existing controllers

  8. In service inspection for steam generator tubes

    International Nuclear Information System (INIS)

    Comby, R.; Eyrolles, Ph.

    1988-01-01

    In this paper the authors show the means putting in place for examination of steam generators tubes. These means (eddy current probes, ultrasonic testing) associated with a knowledge on degradation phenomena allow mapping controlled tubes and limiting undesirable obturations [fr

  9. Steam generators for nuclear power plants

    International Nuclear Information System (INIS)

    Tillequin, Jean

    1975-01-01

    The role and the general characteristics of steam generators in nuclear power plants are indicated, and particular types are described according to the coolant nature (carbon dioxide, helium, light water, heavy water, sodium) [fr

  10. US PWR steam generator management: An overview

    International Nuclear Information System (INIS)

    Welty, C.S. Jr.

    1997-01-01

    This paper provides an overview on the status of steam generator management activities in US PWRs, and includes: (1) an overview of the impact of steam generator problems; (2) a brief discussion of historical damage trends and the current damage mechanism of most concern; (3) a discussion of the elements of open-quotes steam generator managementclose quotes; and (4) a description of the approach being followed to implement a degradation-specific protocol for tubing inspection and repair. This paper was prepared in conjunction with another paper presented during the Plenary Session of this Conference, open-quotes Steam Generator Degradation: Current Mitigation Strategies for Controlling Corrosionclose quotes, and is provided as a supplement to that material

  11. Steam Injection For Soil And Aquifer Remediation

    Science.gov (United States)

    The purpose of this Issue Paper is to provide to those involved in assessing remediation technologies for specific sites basic technical information on the use of steam injection for the remediation of soils and aquifers that are contaminated by...

  12. LABORATORY SCALE STEAM INJECTION TREATABILITY STUDIES

    Science.gov (United States)

    Laboratory scale steam injection treatability studies were first developed at The University of California-Berkeley. A comparable testing facility has been developed at USEPA's Robert S. Kerr Environmental Research Center. Experience has already shown that many volatile organic...

  13. ENERGY STAR Certified Commercial Steam Cookers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 1.2 ENERGY STAR Program Requirements for Commercial Steam Cookers that are effective as...

  14. Infrared technique for measuring steam density

    International Nuclear Information System (INIS)

    Snyder, S.C.; Baker, A.G.

    1982-01-01

    A prototype infrared steam densitometer using a two-wavelength, dual-beam technique was developed. Tests were performed on dry steam flows with this technique, which uses two narrow bandwidths of infrared light in the region of 0.9 to 3.0 μm. One wavelength is absorbed by steam, while the other is not. The latter wavelength is used to account for nonabsorptive light losses. In addition to the beam that traverses the steam flow, a reference beam that does not traverse the flow allows the light source to be monitored. The theory of the device is presented, along with a description of the components and of the system's operation. Test results are also presented

  15. Forming a cohesive steam generator maintenance strategy

    International Nuclear Information System (INIS)

    Poudroux, G.

    1991-01-01

    In older nuclear plants, steam generator tube bundles are the most fragile part of the reactor coolant system. Steam generator tubes are subject to numerous types of loading, which can lead to severe degradation (corrosion and wear phenomena). Preventive actions, such as reactor coolant temperature reduction or increasing the plugging limit and their associated analyses, can increase steam generator service life. Beyond these preventive actions, the number of affected tubes and the different locations of the degradations that occur often make repair campaigns necessary. Framatome has developed and qualified a wide range of treatment and repair processes. They enable careful management of the repair campaigns, to avoid reaching the maximum steam generator tube plugging limit, while optimizing the costs. Most of the available repair techniques allow a large number of affected tubes to be treated. Here we look only at those techniques that should be taken into account when defining a maintenance strategy. (author)

  16. CRBRP steam-generator design evolution

    International Nuclear Information System (INIS)

    Geiger, W.R.; Gillett, J.E.; Lagally, H.O.

    1983-01-01

    The overall design of the CRBRP Steam Generator is briefly discussed. Two areas of particular concern are highlighted and considerations leading to the final design are detailed. Differential thermal expansion between the shell and the steam tubes is accommodated by the tubes flexing in the curved section of the shell. Support of the tubes by the internals structure is essential to permit free movement and minimize tube wear. Special spacer plate attachment and tube hole geometry promote unimpeded axial movement of the tubes by allowing individual tubes to rotate laterally and by providing lateral movement of the spacer plates relative to the adjacent support structure. The water/steam heads of the CRBRP Steam Generator are spherical heads welded to the lower and upper tubesheets. They were chosen principally because they provide a positively sealed system and result in more favorable stresses in the tubesheets when compared to mechanically attached steamheads

  17. Reconstruction of steam generators super emergency feadwater supply system (SHNC) and steam dump stations to the atmosphere system PSA

    International Nuclear Information System (INIS)

    Kuzma, J.

    2001-01-01

    Steam Generators Super Emergency Feadwater Supply System (SHNC) and Steam Dump Stations to the Atmosphere System (PSA) are two systems which cooperate to remove residual heat from reactor core after seismic event. SHNC assure feeding of the secondary site of steam generator (Feed) where after heat removal.from primary loops, is relieved to the atmosphere by PSA (Bleed) in form of steam. (author)

  18. Steam generation at Rihand STPP Stage 1

    Energy Technology Data Exchange (ETDEWEB)

    1987-12-01

    The steam generation plant at Rihand in India has two 500 MW boilers. The boilers are of the balanced draught, single cell, radiant furnace type, and are controlled automatically. Cochran Thermax shell type auxillary steam boilers are used for preheating air to the main boilers and for heating fuel oil during storage and pumping. Electrostatic precipitators and ash handling plants are provided to keep dust and ash within limits. 2 figs.

  19. Steam explosions in light water reactors

    International Nuclear Information System (INIS)

    1981-01-01

    The report deals with a postulated accident caused by molten fuel falling into the lower plenum of the containment of a reactor. The analysis which is presented in the report shows that the thermal energy released in the resulting steam explosion is not enough to destroy the pressure vessel or the containment. The report was prepared for the Swedish Governmental Committee on steam explosion in light water reactors. It includes statements issued by internationally well-known specialists. (G.B.)

  20. Cogeneration steam turbines from Siemens: New solutions

    Science.gov (United States)

    Kasilov, V. F.; Kholodkov, S. V.

    2017-03-01

    The Enhanced Platform system intended for the design and manufacture of Siemens AG turbines is presented. It combines organizational and production measures allowing the production of various types of steam-turbine units with a power of up to 250 MWel from standard components. The Enhanced Platform designs feature higher efficiency, improved reliability, better flexibility, longer overhaul intervals, and lower production costs. The design features of SST-700 and SST-900 steam turbines are outlined. The SST-700 turbine is used in backpressure steam-turbine units (STU) or as a high-pressure cylinder in a two-cylinder condensing turbine with steam reheat. The design of an SST-700 single-cylinder turbine with a casing without horizontal split featuring better flexibility of the turbine unit is presented. An SST-900 turbine can be used as a combined IP and LP cylinder (IPLPC) in steam-turbine or combined-cycle power units with steam reheat. The arrangements of a turbine unit based on a combination of SST-700 and SST-900 turbines or SST-500 and SST-800 turbines are presented. Examples of this combination include, respectively, PGU-410 combinedcycle units (CCU) with a condensing turbine and PGU-420 CCUs with a cogeneration turbine. The main equipment items of a PGU-410 CCU comprise an SGT5-4000F gas-turbine unit (GTU) and STU consisting of SST-700 and SST-900RH steam turbines. The steam-turbine section of a PGU-420 cogeneration power unit has a single-shaft turbine unit with two SST-800 turbines and one SST-500 turbine giving a power output of N el. STU = 150 MW under condensing conditions.

  1. Steam generator in the SNR-project

    International Nuclear Information System (INIS)

    van Westenbrugge, J.K.

    1979-01-01

    The design philosophy of steam generators for 1300 MWe LMFBR's is presented. The basis for this philosophy is the present experience with the licensing of the SNR-300. This experience is reported. The approach for the steam generators for the 1300 MWe LMFBR is elaborated on, both for accident prevention and damage limitation, for the component itself as well as for the system design. Both Design Base Accident and Hypothetical Accidents are discussed. 8 refs

  2. NIST/ASME Steam Properties Database

    Science.gov (United States)

    SRD 10 NIST/ASME Steam Properties Database (PC database for purchase)   Based upon the International Association for the Properties of Water and Steam (IAPWS) 1995 formulation for the thermodynamic properties of water and the most recent IAPWS formulations for transport and other properties, this updated version provides water properties over a wide range of conditions according to the accepted international standards.

  3. New steam generators slated for nuclear units

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This article is a brief discussion of Duke Power's plans to replace steam generators at its McGuire and Catawba nuclear units. A letter of intent to purchase (from Babcock and Wilcox) the 12 Westinghouse steam generators has been signed, but no constructor has been selected at this time. This action is brought about by the failures of more than 3000 tubes in these units

  4. Report of studies on geothermal steam

    Energy Technology Data Exchange (ETDEWEB)

    1954-09-01

    At the time of this report the exploitation of geothermal steam wells was only in the experimental stage. A great deal of information was derived for future use however. The steam is described in terms of its origin and characteristics and the life expectancy of the wells is estimated. Experimental work in Otake, Hakuryu, Beppu and Naruko is described. The power generation station at Larderello, Italy, is discussed. Extensive data from the experimental wells are summarized in tables.

  5. Control system for fluid heated steam generator

    Science.gov (United States)

    Boland, J.F.; Koenig, J.F.

    1984-05-29

    A control system for controlling the location of the nucleate-boiling region in a fluid heated steam generator comprises means for measuring the temperature gradient (change in temperature per unit length) of the heating fluid along the steam generator; means for determining a control variable in accordance with a predetermined function of temperature gradients and for generating a control signal in response thereto; and means for adjusting the feedwater flow rate in accordance with the control signal.

  6. Development of a steam generator lancing system

    International Nuclear Information System (INIS)

    Jeong, Woo-Tae; Kim, Seok-Tae; Hong, Sung-Yull

    2006-01-01

    It is recommended to clean steam generators of nuclear power plants during plant outages. Under normal operations, sludge is created and constantly accumulates in the steam generators. The constituents of this sludge are different depending on each power plant characteristics. The sludge of the Kori Unit 1 steam generator, for example, was found to be composed of 93% ferrous oxide, 3% carbon and 1% of silica oxide and nickel oxide each. The research to develop a lancing system that would remove sludge deposits from the tubesheet of a steam generator was started in 1998 by the Korea Electric Power Research Institute (KEPRI) of the Korea Electric Power Corporation (KEPCO). The first commercial domestic lancing system in Korea, and KALANS-I Lancing System, was completed in 2000 for Kori Unit 1 for cleaning the tubesheet of its Westinghouse Delta-60 steam generator. Thereafter, the success of the development and site implementation of the KALANS-I lancing system for YGN Units 1 and 2 and Ulchin Units 3 and 4 was also realized in 2004 for sludge removal at those sites. The upper bundle cleaning system for Westinghouse model F steam generators is now under development

  7. Reciprocating wear in a steam environment

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.J.; Gee, M.G. [National Physical Laboratory, Teddington, Middlesex (United Kingdom)

    2010-07-01

    Tests to simulate the wear between sliding components in steam power plant have been performed using a low frequency wear apparatus at elevated temperatures under static load, at ambient pressure, in a steam environment. The apparatus was modified to accept a novel method of steam delivery. The materials tested were pre-exposed in a flowing steam furnace at temperature for either 500 or 3000 hours to provide some simulation of long term ageing. The duration of each wear test was 50 hours and tests were also performed on as-received material for comparison purposes. Data has been compared with results of tests performed on non-oxidised material for longer durations and also on tests without steam to examine the effect of different environments. Data collected from each test consists of mass change, stub height measurement and friction coefficient as well as visual inspection of the wear track. Within this paper, it is reported that both pre-ageing and the addition of steam during testing clearly influence the friction between material surfaces. (orig.)

  8. Design of Hybrid Steam-In Situ Combustion Bitumen Recovery Processes

    International Nuclear Information System (INIS)

    Yang Xiaomeng; Gates, Ian D.

    2009-01-01

    Given enormous capital costs, operating expenses, flue gas emissions, water treatment and handling costs of thermal in situ bitumen recovery processes, improving the overall efficiency by lowering energy requirements, environmental impact, and costs of these production techniques is a priority. Steam-assisted gravity drainage (SAGD) is the most widely used in situ recovery technique in Athabasca reservoirs. Steam generation is done on surface and consequently, because of heat losses, the energy efficiency of SAGD can never be ideal with respect to the energy delivered to the sandface. An alternative to surface steam generation is in situ combustion (ISC) where heat is generated within the formation through injection of oxygen at a sufficiently high pressure to initiate combustion of bitumen. In this manner, the heat from the combustion reactions can be used directly to mobilize the bitumen. As an alternative, the heat can be used to generate steam within the formation which then is the agent to move heat in the reservoir. In this research, alternative hybrid techniques with simultaneous and sequential steam-oxygen injection processes are examined to maximize the thermal efficiency of the recovery process. These hybrid processes have the advantage that during ISC, steam is generated within the reservoir from injected and formation water and as a product of oxidation. This implies that ex situ steam generation requirements are reduced and if there is in situ storage of combustion gases, that overall gas emissions are reduced. In this research, detailed reservoir simulations are done to examine the dynamics of hybrid processes to enable design of these processes. The results reveal that hybrid processes can lower emitted carbon dioxide-to-oil ratio by about 46%, decrease the consumed natural gas-to-oil ratio by about 73%, reduce the cumulative energy-to-oil ratio by between 40% and 70% compared to conventional SAGD, and drop water consumption per unit oil produced

  9. Description of steam condensation phenomena during the loss-of-coolant accident

    International Nuclear Information System (INIS)

    McCauley, E.W.; Holman, G.S.; Aust, E.; Furst, H.; Schwan, H.; Vollbrandt, J.

    1981-01-01

    Study of results from the full scale multivent pressure suppression experiment conducted by the GKSS Laboratory has developed an improved understanding of the dynamic, oscillatory steam condensation events and related loading functions which occur during the hypothetical loss-of-coolant accident in a boiling water nuclear reactor. Due to the unique measurements systems which combines both cinematic and digital data, qualified correlation between the dynamic physical variables and the associated two-phase thermo-hydraulic phenomena has been obtained

  10. The Methodological Dynamism of Grounded Theory

    Directory of Open Access Journals (Sweden)

    Nicholas Ralph

    2015-11-01

    Full Text Available Variations in grounded theory (GT interpretation are the subject of ongoing debate. Divergences of opinion, genres, approaches, methodologies, and methods exist, resulting in disagreement on what GT methodology is and how it comes to be. From the postpositivism of Glaser and Strauss, to the symbolic interactionist roots of Strauss and Corbin, through to the constructivism of Charmaz, the field of GT methodology is distinctive in the sense that those using it offer new ontological, epistemological, and methodological perspectives at specific moments in time. We explore the unusual dynamism attached to GT’s underpinnings. Our view is that through a process of symbolic interactionism, in which generations of researchers interact with their context, moments are formed and philosophical perspectives are interpreted in a manner congruent with GT’s essential methods. We call this methodological dynamism, a process characterized by contextual awareness and moment formation, contemporaneous translation, generational methodology, and methodological consumerism.

  11. Why extraction lines and heaters in the turbine-condenser steam space should be lagged

    Energy Technology Data Exchange (ETDEWEB)

    Burns, J.M.; Haynes, C.J.

    1998-07-01

    Deregulated utilities face conditions today that necessitate their nuclear and fossil steam plants have the best possible heat rates. The low pressure turbine exhaust and condenser areas are known to be particularly sensitive to betterment. One relatively modest but cost effective heat rate improvement and one whose function and design is often misunderstood is the insulation of the extraction lines and heaters that are located within the turbine-condenser steam space. This paper discusses the dynamic environment of that turbine exhaust region and quantifies the application and benefit of stainless steel lagging to the extraction lines and heater shells within. The paper first focuses on the high energy, non-uniform steam flows of the turbine exhaust and how that impacts the heat losses, mechanical design and support of any components located inside that space. It then examines and quantifies the varieties of heat transfer from the heaters and extraction lines to the passing lower temperature, moist, high velocity turbine exhaust steam as it travels to the condenser. A new relationship is developed that defines the predominantly evaporative heat transfer mechanism on the exterior surfaces in contact with the exhaust steam. For a typical 630 MW fossil plant with three heater of different temperature levels in the steam space as exemplified by the US Generation fossil fired Brayton Point 3, the paper determined the additional condenser heat load and extra extraction steam. The paper lastly concluded that in this case, lagging the larger diameter lines of the lowest pressure heater and the heater itself is likely not cost-effective.

  12. GT-MHR COMMERCIALIZATION STUDY TECHNICAL PROGRESS AND COST MANAGEMENT REPORT FOR THE PERIOD AUGUST 1 THROUGH AUGUST 31, 2003

    International Nuclear Information System (INIS)

    Shenoy, A.S.

    2003-01-01

    OAK A271 GT-MHR COMERCIALiZATION STUDY TECHNICAL PROGRESS AND COST MANAGEMENT REPORT FOR THE PERIOD AUGUST 1 THROUGH AUGUST 31, 2003. In the process of fabricating the MHR-1 irradiation test capsule, Petten has advised that three thermocouples (out of 24) and the Self Powered Neutron detector were damaged during high temperature brazing with the upper capsule lid. Procurement of new TCs and SPN is in process but there will be a delay in the irradiation test of about nine weeks. Startup of the irradiation is now projected to be July or August 2004. In preparation for performing the nuclear design analysis activities required by the advanced fuel studies task, a complete 3-D nuclear design analysis is first being performed of the GT-MHR reference design. This will serve as the baseline for studies of the advanced fuel nuclear design performance

  13. GT-MHR as economical highly efficient inherently safe modular gas cooled reactor for electric power generation

    International Nuclear Information System (INIS)

    Baydakov, A.G.; Kodochigov, N.G.; Kuzavkov, N.G.; Vorontsov, V.E.

    2001-01-01

    The Gas Turbine Modular Helium Reactor (GT-MHR) project is a joint effort of organisations in the Russian Federation co-ordinated by the Ministry on Atomic Energy (MINATOM), General Atomics in the United States, Framatome in France, and Fuji Electric in Japan. This paper describes the structure, objectives and history of the GT-MHR project, as well as the plant design, including plant layout, components and fuel. It summarises the results of evaluations of the design safety characteristics and economics, for both a plutonium fueled single module and a uranium fueled four module plant. The plans and anticipated structure for an international project to construct the plant are also summarised. (author)

  14. [Effects of nitriles and amides on the growth and the nitrile hydratase activity of the Rhodococcus sp. strain gt1].

    Science.gov (United States)

    Maksimov, A Iu; Kuznetsova, M V; Ovechkina, G V; Kozlov, S V; Maksimova, Iu G; Demakov, V A

    2003-01-01

    Effects of some nitriles and amides, as well as glucose and ammonium, on the growth and the nitrile hydratase (EC 4.2.1.84) activity of the Rhodococcus sp. strain gt1 isolated from soil were studied. The activity of nitrile hydratase mainly depended on carbon and nitrogen supply to cells. The activity of nitrile hydratase was high in the presence of glucose and ammonium at medium concentrations and decreased at concentrations of glucose more than 0.3%. Saturated unsubstituted aliphatic nitriles and amides were found to be a good source of nitrogen and carbon. However, the presence of nitriles and amides in the medium was not absolutely necessary for the expression of the activity of nitrile hydratase isolated from the Rhodococcus sp. strain gt1.

  15. Physical Activity Assessment with the ActiGraph GT3X and Doubly Labeled Water.

    Science.gov (United States)

    Chomistek, Andrea K; Yuan, Changzheng; Matthews, Charles E; Troiano, Richard P; Bowles, Heather R; Rood, Jennifer; Barnett, Junaidah B; Willett, Walter C; Rimm, Eric B; Bassett, David R

    2017-09-01

    To compare the degree to which four accelerometer metrics-total activity counts per day (TAC per day), steps per day (steps per day), physical activity energy expenditure (PAEE) (kcal·kg·d), and moderate- to vigorous-intensity physical activity (MVPA) (min·d)-were correlated with PAEE measured by doubly labeled water (DLW). Additionally, accelerometer metrics based on vertical axis counts and triaxial counts were compared. This analysis included 684 women and 611 men age 43 to 83 yr. Participants wore the Actigraph GT3X on the hip for 7 d twice during the study and the average of the two measurements was used. Each participant also completed one DLW measurement, with a subset having a repeat. PAEE was estimated by subtracting resting metabolic rate and the thermic effect of food from total daily energy expenditure estimated by DLW. Partial Spearman correlations were used to estimate associations between PAEE and each accelerometer metric. Correlations between the accelerometer metrics and DLW-determined PAEE were higher for triaxial counts than vertical axis counts. After adjusting for weight, age, accelerometer wear time, and fat free mass, the correlation between TAC per day based on triaxial counts and DLW-determined PAEE was 0.44 in women and 0.41 in men. Correlations for steps per day and accelerometer-estimated PAEE with DLW-determined PAEE were similar. After adjustment for within-person variation in DLW-determined PAEE, the correlations for TAC per day increased to 0.61 and 0.49, respectively. Correlations between MVPA and DLW-determined PAEE were lower, particularly for modified bouts of ≥10 min. Accelerometer measures that represent total activity volume, including TAC per day, steps per day, and PAEE, were more highly correlated with DLW-determined PAEE than MVPA using traditional thresholds and should be considered by researchers seeking to reduce accelerometer data to a single metric.

  16. Real-time simulation of MHD/steam power plants by digital parallel processors

    International Nuclear Information System (INIS)

    Johnson, R.M.; Rudberg, D.A.

    1981-01-01

    Attention is given to a large FORTRAN coded program which simulates the dynamic response of the MHD/steam plant on either a SEL 32/55 or VAX 11/780 computer. The code realizes a detailed first-principle model of the plant. Quite recently, in addition to the VAX 11/780, an AD-10 has been installed for usage as a real-time simulation facility. The parallel processor AD-10 is capable of simulating the MHD/steam plant at several times real-time rates. This is desirable in order to develop rapidly a large data base of varied plant operating conditions. The combined-cycle MHD/steam plant model is discussed, taking into account a number of disadvantages. The disadvantages can be overcome with the aid of an array processor used as an adjunct to the unit processor. The conversion of some computations for real-time simulation is considered

  17. Effects of Huang Bai (Phellodendri Cortex and Three Other Herbs on GnRH and GH Levels in GT1–7 and GH3 Cells

    Directory of Open Access Journals (Sweden)

    Sun Haeng Lee

    2016-01-01

    Full Text Available The present study was to evaluate the effects of Huang Bai, Zhi Mu, Mai Ya, and Xia Ku Cao on hormone using the GT1–7 and GH3 cells. The GT1–7 and GH3 cell lines were incubated with DW; DMSO; and 30, 100, or 300 μg/mL of one of the four extract solutions in serum-free media for 24 hours. The MTT assay was performed to determine the cytotoxicity of the four herbs. The GT1–7 and GH3 cells were incubated in DW, estradiol (GT1–7 only, or noncytotoxic herb solutions in serum-free medium for 24 hours. A quantitative RT-PCR and western blot were performed to measure the GnRH expression in GT1–7 cells and GH expression in GH3 cells. Huang Bai, Zhi Mu, Xia Ku Cao, and Mai Ya inhibited the GnRH mRNA expression in GT1–7 cells, whereas Huang Bai enhanced GH mRNA expression in GH3 cells. Additionally, Xia Ku Cao inhibited GnRH protein expression in GT1–7 cells and Huang Bai promoted GH protein expression in GH3 cells. The findings suggest that Huang Bai can delay puberty by inhibiting GnRH synthesis in the hypothalamus while also accelerating growth by promoting GH synthesis and secretion in the pituitary.

  18. STEAM Enacted: A Case Study of a Middle School Teacher Implementing STEAM Instructional Practices

    Science.gov (United States)

    Herro, Danielle; Quigley, Cassie

    2016-01-01

    This paper examines the implementation practices of a 6th grade middle school teacher enacting STEAM (science, technology, engineering, art and math) teaching in his classroom after participating in a 45-hour STEAM professional development. Case study is used to detail the process, successes, and challenges. Project-based learning, technology…

  19. Synthesis and optimization of steam system networks. 2. Multiple steam levels

    CSIR Research Space (South Africa)

    Price, T

    2010-08-01

    Full Text Available The use of steam in heat exchanger networks (HENs) can be reduced by the application of heat integration with the intention of debottlenecking the steam boiler and indirectly reducing the water requirement [Coetzee and Majozi. Ind. Eng. Chem. Res...

  20. Changes of wood cell walls in response to hygro-mechanical steam treatment.

    Science.gov (United States)

    Guo, Juan; Song, Kunlin; Salmén, Lennart; Yin, Yafang

    2015-01-22

    The effects of compression combined with steam treatment (CS-treatment), i.e. a hygro-mechanical steam treatment on Spruce wood were studied on a cell-structure level to understand the chemical and physical changes of the secondary cell wall occurring under such conditions. Specially, imaging FT-IR microscopy, nanoindentation and dynamic vapour absorption were used to track changes in the chemical structure, in micromechanical and hygroscopic properties. It was shown that CS-treatment resulted in different changes in morphological, chemical and physical properties of the cell wall, in comparison with those under pure steam treatment. After CS-treatment, the cellular structure displayed significant deformations, and the biopolymer components, e.g. hemicellulose and lignin, were degraded, resulting in decreased hygroscopicity and increased mechanical properties of the wood compared to both untreated and steam treated wood. Moreover, CS-treatment resulted in a higher degree of degradation especially in earlywood compared to a more uniform behaviour of wood treated only by steam. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Analysis of the Instability Phenomena Caused by Steam in High-Pressure Turbines

    Directory of Open Access Journals (Sweden)

    Paolo Pennacchi

    2011-01-01

    Full Text Available Instability phenomena in steam turbines may happen as a consequence of certain characteristics of the steam flow as well as of the mechanical and geometrical properties of the seals. This phenomenon can be modeled and the raise of the steam flow and pressure causes the increase of the cross coupled coefficients used to model the seal stiffness. As a consequence, the eigenvalues and eigenmodes of the mathematical model of the machine change. The real part of the eigenvalue associated with the first flexural normal mode of the turbine shaft may become positive causing the conditions for unstable vibrations. The original contribution of the paper is the application of a model-based analysis of the dynamic behavior of a large power unit, affected by steam-whirl instability phenomena. The model proposed by the authors allows studying successfully the experimental case. The threshold level of the steam flow that causes instability conditions is analyzed and used to define the stability margin of the power unit.

  2. Development of compressible density-based steam explosion simulation code ESE-2

    International Nuclear Information System (INIS)

    Leskovar, M.

    2004-01-01

    A steam explosion is a fuel coolant interaction process by which the energy of the corium is transferred to water in a time-scale smaller than the time-scale for system pressure relief and induces dynamic loading of surrounding structures. A strong enough steam explosion in a nuclear power plant could jeopardize the containment integrity and so lead to a direct release of radioactive material to the environment. To help finding answers on open questions regarding steam explosion understanding and modelling, the steam explosion simulation code ESE-2 is being developed. In contrast to the developed simulation code ESE-1, where the multiphase flow equations are solved with pressure-based numerical methods (best suited for incompressible flow), in ESE-2 densitybased numerical methods (best suited for compressible flow) are used. Therefore ESE-2 will enable an accurate treatment of the whole steam explosion process, which consists of the premixing, triggering, propagation and expansion phase. In the paper the basic characteristics of the mathematical model and the numerical solution procedure in ESE-2 are described. The essence of the numerical treatment is that the convective terms in the multiphase flow equations are calculated with the AUSM+ scheme, which is very time efficient since no field-by-field wave decomposition is needed, using second order accurate discretization. (author)

  3. Putative DNA-dependent RNA polymerase in Mitochondrial Plasmid of Paramecium caudatum Stock GT704

    Directory of Open Access Journals (Sweden)

    Trina Ekawati Tallei

    2015-10-01

    Full Text Available Mitochondria of Paramecium caudatum stock GT704 has a set of four kinds of linear plasmids with sizes of 8.2, 4.1, 2.8 and 1.4 kb. The plasmids of 8.2 and 2.8 kb exist as dimers consisting of 4.1- and 1.4-kb monomers, respectively. The plasmid 2.8 kb, designated as pGT704-2.8, contains an open reading frame encodes for putative DNA-dependent RNA polymerase (RNAP. This study reveals that this RNAP belongs to superfamily of DNA/RNA polymerase and family of T7/T3 single chain RNA polymerase and those of mitochondrial plasmid of fungi belonging to Basidiomycota and Ascomycota. It is suggested that RNAP of pGT704-2.8 can perform transcription without transcription factor as promoter recognition. Given that only two motifs were found, it could not be ascertained whether this RNAP has a full function independently or integrated with mtDNA in carrying out its function.

  4. Intermonitor reliability of the GT3X+ accelerometer at hip, wrist and ankle sites during activities of daily living

    International Nuclear Information System (INIS)

    Ozemek, Cemal; Wilkerson, Brittany S; Kaminsky, Leonard A; Kirschner, Monica M; Byun, Wonwoo

    2014-01-01

    The triaxial GT3X+ accelerometer can measure activity counts in the vertical, horizontal right to left, horizontal front to back planes, and can generate a summative score of the three axes represented by vector magnitude (VM). Information on the reliability of the GT3X+ at the hip, wrist and ankle sites, over all axes and VM during activities of daily living (ADL) is lacking in the literature. Forty healthy adults (14 men and 26 women) were randomly assigned to perform 10 of 20 ADL (consisting of sedentary, housework, yard work, locomotive and recreational activities) while wearing two monitors on the hip, wrist and ankle. Subjects performed each ADL over 7 min and the mean activity counts during the last 4 min were used for analyses. Average intraclass correlations between monitors were high for the three sites for each axis and VM (hip: 0.943, 0.857, 0.864 and 0.966, respectively; wrist: 0.994, 0.963, 0.961 and 0.989, respectively; ankle: 0.977, 0.979, 0.927 and 0.986, respectively). These data suggest that GT3X+ accelerometers measurements made from the hip, wrist and ankle sites are reliable during ADL across all axes and VM. (paper)

  5. Cleaning device for steam units in a nuclear power plant

    International Nuclear Information System (INIS)

    Sasamuro, Takemi.

    1978-01-01

    Purpose: To prevent radioactive contamination upon dismantling and inspection of steam units such as a turbine to a building containing such units and the peripheral area. Constitution: A steam generator indirectly heated by steam supplied from steam generating source in a separate system containing no radioactivity is provided to produce cleaning steam. A cleaning steam pipe is connected by way of a stop valve between separation valve of a nuclear power plant steam pipe and a high pressure turbine. Upon cleaning, the separation valve is closed, and steam supplied from the cleaning steam pipe is flown into a condenser. The water thus condensated is returned by way of a feed water heater and a condenser to a water storage tank. (Nakamura, S.)

  6. Cavity structural integrity evaluation of steam explosion using LS-DYNA

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae-Young; Park, Chang-Hwan [FNC Technology Co. Ltd., Yongin (Korea, Republic of); Kim, Kap-sun [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    For investigating the mechanical response of the newly-designed NPP against an steam explosion, the cavity structural integrity evaluation was performed, in which the mechanical load resulted from a steam explosion in the reactor cavity was calculated. In the evaluation, two kinds of approach were considered, one of which is a deterministic manner and the other is a probabilistic one. In this report, the procedure and the results of the deterministic analysis are presented When entering the severe accident, the core is relocated to the lower head. In this case, an Ex-Vessel Steam Explosion(EVSE) can occur. It can threaten the structural integrity of the cavity due to the load applied to the walls or slabs of the cavity. The large amount of the energy transmitted from interaction between the molten corium and the water causes a dynamic loading onto the concrete walls resulting not only to affect the survivability of the various equipment but also to threaten the integrity of the containment. In this report, the response of the cavity wall structure is analyzed using the nonlinear finite element analysis (FEA) code. The resulting stress and strain of the structure were evaluated by the criteria in NEI07-13. Until now, deterministic analysis was performed via finite element analysis for the dynamic load generated by the steam explosion to investigate the effect on the cavity structure. A deterministic method was used in this study using the specific values of material properties and clearly defined steam explosion pressure curve. The results showed that the rebar and the liner are kept intact even at the high pressure pulse given by the steam explosion. The liner integrity is more critical to judge the preservation of the lean-tightness. In the meantime, there were found cracks in concrete media.

  7. TPH2 -703G/T SNP may have important effect on susceptibility to suicidal behavior in major depression.

    Science.gov (United States)

    Yoon, Ho-Kyoung; Kim, Yong-Ku

    2009-04-30

    Serotonergic system-related genes can be good candidate genes for both major depressive disorder (MDD) and suicidal behavior. In this study, we aimed to investigate the association of serotonin 2A receptor gene -1438A/G SNP (HTR2A -1438A/G), tryptophan hydroxylase 2 gene -703G/T SNP (TPH2 -703G/T) and serotonin 1A receptor C-1019G (HTR1A C-1019G) with suicidal behavior. One hundred and eighty one suicidal depressed patients and 143 non-suicidal depressed patients who met DSM-IV criteria for major depressive disorder were recruited from patients who were admitted to Korea University Ansan Hospital. One hundred seventy six normal controls were healthy volunteers who were recruited by local advertisement. Patients and normal controls were genotyped for HTR2A -1438A/G, TPH2 -703G/T and 5-HT1A C-1019G. The suicidal depressed patients were evaluated by the lethality of individual suicide attempts using Weisman and Worden's risk-rescue rating (RRR) and the Lethality Suicide Attempt Rating Scale-updated (LSARS-II). In order to assess the severity of depressive symptoms of patients, Hamilton's Depression Rating Scale (HDRS) was administered. Genotype and allele frequencies were compared between groups by chi(2) statistics. Association of genotype of the candidate genes with the lethality of suicidal behavior was examined with ANOVA by comparing the mean scores of LSARS and RRR according to the genotype. There were statistically significant differences in the genotype distributions and allele frequencies of TPH2 -703G/T between the suicidal depressive group and the normal control group. The homozygous allele G (G/G genotype) frequency was significantly higher in suicidal depressed patients than in controls. However, no differences in either genotype distribution or in allele frequencies of HTR2A -1438A/G and HTR1A C-1019G were observed between the suicidal depressed patients, the non-suicidal depressed patients, and the normal controls. There were no differences in the

  8. IAEA activities on steam generator life management

    International Nuclear Information System (INIS)

    Gueorguiev, B.; Lyssakov, V.; Trampus, P.

    2002-01-01

    The International Atomic Energy Agency (IAEA) carries out a set of activities in the field of Nuclear Power Plant (NPP) life management. Main activities within this area are implemented through the Technical Working Group on Life Management of NPPs, and mostly concentrated on studies of understanding mechanisms of degradation and their monitoring, optimisation of maintenance management, economic aspects, proven practices of and approaches to plant life management including decommissioning. The paper covers two ongoing activities related to steam generator life management: the International Database on NPP Steam Generators and the Co-ordinated Research Project on Verification of WWER Steam Generator Tube Integrity (WWER is the Russian designed PWR). The lifetime assessment of main components relies on an ability to assess their condition and predict future degradation trends, which to a large extent is dependent on the availability of relevant data. Effective management of ageing and degradation processes requires a large amount of data. Several years ago the IAEA started to work on the International Database on NPP Life Management. This is a multi-module database consisting of modules such as reactor pressure vessels materials, piping, steam generators, and concrete structures. At present the work on pressure vessel materials, on piping as well as on steam generator is completed. The paper will present the concept and structure of the steam generator module of the database. In countries operating WWER NPPs, there are big differences in the eddy current inspection strategy and practice as well as in the approach to steam generator heat exchanger tube structural integrity assessment. Responding to the need for a co-ordinated research to compare eddy current testing results with destructive testing using pulled out tubes from WWER steam generators, the IAEA launched this project. The main objectives of the project are to summarise the operating experiences of WWER

  9. Steam generator replacement at Surry Power Station

    International Nuclear Information System (INIS)

    McKay, H.S.

    1982-01-01

    The purposes of the steam generator repair program at Surry Power Station were to repair the tube degradation caused by corrosion-related phenomena and to restore the integrity of the steam generators to a level equivalent to new equipment. The repair program consisted of (1) replacing the existing lower-shell assemblies with new ones and (2) adding new moisture separation equipment to the upper-shell assemblies. These tasks required that several pieces of reactor coolant piping, feedwater piping, main steam piping, and the steam generator be cut and refurbished for reinstallation after the new lower shell was in place. The safety implications and other potential effects of the repair program both during the repair work and after the unit was returned to power were part of the design basis of the repair program. The repair program has been completed on Unit 2 without any adverse effects on the health and safety of the general public or to the personnel engaged in the repair work. Before the Unit 1 repair program began, a review of work procedures and field changes for the Unit 2 repair was conducted. Several major changes were made to avoid recurrence of problems and to streamline procedures. Steam generator replacements was completed on June 1, 1981, and the unit is presently in the startup phase of the outrage

  10. Darlington steam generator life assurance program

    International Nuclear Information System (INIS)

    Jelinski, E.; Dymarski, M.; Maruska, C.; Cartar, E.

    1995-01-01

    The Darlington Nuclear Generating Station belonging to Ontario Hydro is one of the most modern and advanced nuclear generating stations in the world. Four reactor units each generate 881 net MW, enough to provide power to a major city, and representing approximately 20% of the Ontario grid. The nuclear generating capacity in Ontario represents approximately 60% of the grid. In order to look after this major asset, many proactive preventative and predictive maintenance programs are being put in place. The steam generators are a major component in any power plant. World wide experience shows that nuclear steam generators require specialized attention to ensure reliable operation over the station life. This paper describes the Darlington steam generator life assurance program in terms of degradation identification, monitoring and management. The requirements for chemistry control, surveillance of process parameters, surveillance of inspection parameters, and the integration of preventative and predictive maintenance programs such as water lancing, chemical cleaning, RIHT monitoring, and other diagnostics to enhance our understanding of life management issues are identified and discussed. We conclude that we have advanced proactive activities to avoid and to minimize many of the problems affecting other steam generators. An effective steam generator maintenance program must expand the knowledge horizon to understand life limiting processes and to analyze and synthesize observations with theory. (author)

  11. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  12. Thermohydraulic verification during THTR steam generator commissioning

    International Nuclear Information System (INIS)

    Henry, C.; Elter, C.

    1988-01-01

    In one of the six THTR 300 steam generators thermocouples are installed inside the heat transfer tube bundles for measuring the gas and steam temperatures. Fluid temperature distribution measurements along and across the helix bundle have been recorded in its first months of operation over a load range of 40% up to 100% for steady state and transient conditions. Using these measurements as well as the rest of the operating instrumentation. the computer programs for the design of heat exchanger heat transfer areas are verified. The temperature measurements for steady state conditions are compared with predictions obtained in the design stage. In these codes. the heat transferred from the outside helium gas to the water/steam inside the tubes is determined in discrete steps along the heating surface by one- and two-phase heat transfer correlations. The degree of conformity between prediction and measurement is discussed and compared with more recent correlations. (author)

  13. Structural integrity analysis of a steam turbine

    International Nuclear Information System (INIS)

    Villagarcia, Maria P.

    1997-01-01

    One of the most critical components of a power utility is the rotor of the steam turbine. Catastrophic failures of the last decades have promoted the development of life assessment procedures for rotors. The present study requires the knowledge of operating conditions, component geometry, the properties of materials, history of the component, size, location and nature of the existing flaws. The aim of the present work is the obtention of a structural integrity analysis procedure for a steam turbine rotor, taking into account the above-mentioned parameters. In this procedure, a stress thermal analysis by finite elements is performed initially, in order to obtain the temperature and stress distribution for a subsequent analysis by fracture mechanics. The risk of a fast fracture due to flaws in the central zone of the rotor is analyzed. The procedure is applied to an operating turbine: the main steam turbine of the Atucha I nuclear power utility. (author)

  14. Steam explosions in sodium cooled breeder reactors

    International Nuclear Information System (INIS)

    Lundell, B.

    1982-01-01

    Steam explosion is considered a physical process which transport heat from molten fuel to liquid coolant so fast that the coolant starts boiling in an explosion-like manner. The arising pressure waves transform part of the thermal energy to mechanical energy. This can stress the reactor tank and threaten its hightness. The course of the explosion has not been theoretical explained. Experimental results indicate that the probability of steam explosions in a breeder reactor is small. The efficiency of the transformation of the heat of fusion into mechanical energy in substantially lower than the theoretical maximum value. The mechanical stress from the steam explosion on the reactor tank does not seem to jeopardize its tightness. (G.B.)

  15. Chemical cleaning of nuclear (PWR) steam generators

    International Nuclear Information System (INIS)

    Welty, C.S. Jr.; Mundis, J.A.

    1982-01-01

    This paper reports on a significant research program sponsored by a group of utilities (the Steam Generator Owners Group), which was undertaken to develop a process to chemically remove corrosion product deposits from the secondary side of pressurized water reactor (PWR) power plant steam generators. Results of this work have defined a process (solvent system and application methods) that is capable of removing sludge and tube-to-tube support plate crevice corrosion products generated during operation with all-volatile treatment (AVT) water chemistry. Considers a plant-specific test program that includes all materials in the steam generator to be cleaned and accounts for the physical locations (proximity and contact) of those materials. Points out that prior to applying the process in an operational unit, the utility, with the participation of the NSSR vendor, must define allowable total corrosion to the materials of construction of the unit

  16. Development of ATSR (Auto Thermal Steam Reformer)

    International Nuclear Information System (INIS)

    Ono, J.; Yoshino, Y.; Kuwabara, T.; Fujisima, S.; Kobayashi, S.; Maruko, S.

    2004-01-01

    'Full text:' Auto-thermal reformers are used popularly for fuel cell vehicle because they are compact and can start up quickly. On the other hand, steam reformers are used for stationary fuel cell power plant because they are good thermal efficiency. While, there are many cases using the auto- thermal reformer for stationary use with expectation of cost reduction in USA, as well. However, they are still insufficient for its durability, compactness and cost. We have been developing the new type of fuel processing system that is auto-thermal steam reformer (ATSR), which is hybrid of a conventional steam reformer (STR) and a conventional auto-thermal reformer (ATR). In this study, some proto-type of ATSR for field test were designed, tried manufacturing and tested performance and durability. And we have tried to operate with fuel cell stack to evaluate the system interface performance, that is, operability and controllability. (author)

  17. New ferritic steels for advanced steam plants

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, K.H; Koenig, H. [GEC ALSTHOM Energie GmbH, Nuremberg (Germany)

    1998-12-31

    During the last 15-20 years ferritic-martensitic 9-12 % chromium steels have been developed under international research programmes which permit inlet steam temperatures up to approx. 625 deg C and pressures up to about 300 bars, thus leading to improvements in thermal efficiency of around 8 % and a CO{sub 2} reduction of about 20 % versus conventional steam parameters. These new steels are already being applied in 13 European and 34 Japanese power stations with inlet steam temperature up to 610 deg C. This presentation will give an account of the content, scope and results of the research programmes and of the experience gained during the production of components which have been manufactured from the new steels. (orig.) 13 refs.

  18. A steam separator-superheater apparatus

    International Nuclear Information System (INIS)

    Androw, Jean; Bessouat, Roger; Peyrelongue, J.-P.

    1973-01-01

    Description is given of a separator-superheater apparatus comprising an outer enclosure containing a separating-unit and a steam superheating unit according to the main patent. The present addition relates to an improvement in that apparatus, characterized in that the separating unit and the superheating unit, mounted in two distinct portions of the outer enclosure, are divided into the same number of sub-units of each unit being identical and operating in parallel, and in that to each separator sub-unit is associated a superheater sub-unit, said sub-units being mounted in series and located in one in the other of the enclosure two portions, respectively. This can be applied to the treatment of the exhaust steam of a turbine high pressure body, prior to re-injecting said steam into the low pressure body [fr

  19. New ferritic steels for advanced steam plants

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, K H; Koenig, H [GEC ALSTHOM Energie GmbH, Nuremberg (Germany)

    1999-12-31

    During the last 15-20 years ferritic-martensitic 9-12 % chromium steels have been developed under international research programmes which permit inlet steam temperatures up to approx. 625 deg C and pressures up to about 300 bars, thus leading to improvements in thermal efficiency of around 8 % and a CO{sub 2} reduction of about 20 % versus conventional steam parameters. These new steels are already being applied in 13 European and 34 Japanese power stations with inlet steam temperature up to 610 deg C. This presentation will give an account of the content, scope and results of the research programmes and of the experience gained during the production of components which have been manufactured from the new steels. (orig.) 13 refs.

  20. Steam chugging in pressure suppression containment

    International Nuclear Information System (INIS)

    Lee, C.K.B.; Chan, C.K.

    1978-01-01

    The condensation of steam flow in subcooled water was studied by injecting a quasi-steady stream of saturated steam into a pool water at different temperature. From the movies, it was observed that chugging occurred at a frequency on the order of 1 to 2 times a second. In between each chug over a period of approximately half a second, a few bubbles formed and collapsed at the exit of the downcomer. At a mass flow rate of approximately 5.02 Kg/m 2 sec., the chugging process is found to be strongly affected by the bubble formation. At pool temperatures below 50 0 C, the chugging process is dominated by internal chugging which is characterized by high water slug exit velocity, detached steam bubble and lhigh chugging level. Above 50 0 C, the external chugging mode is dominant. The external chugging mode is characterized by pancake bubble shape, low water slug exit velocity, and low chugging level. (author)