WorldWideScience

Sample records for vessel loading operations

  1. Vessel Operating Units (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data for vessels that are greater than five net tons and have a current US Coast Guard documentation number. Beginning in1979, the NMFS...

  2. Vessel Operator System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Operator cards are required for any operator of a charter/party boat and or a commercial vessel (including carrier and processor vessels) issued a vessel permit from...

  3. EDF studies on PWR vessel internal loading

    International Nuclear Information System (INIS)

    Bellet, S.; Vallat, S.

    1998-01-01

    EDF has undertaken some mechanics and thermal-hydraulics studies with the objective of mastering plant phenomena today and in order to numerically predict the behaviour of vessel internals on units planned for the future. From some justifications already underway after in operation incidents (wear and drop time of RCCA rods, fuel deflection, adapter cracks, baffle bolt cracks) we intend to control reactor vessel flows and mechanical behaviour of internal structures. During normal operation, thermal-hydraulic is the main load of vessel internals. The current approach consists of acquiring the capacity to link different calculations, taking care that codes are qualified for physical phenomena and complex 3D geometries. For baffle assembly, a more simple model of this structure has been used to treat the physical phenomena linked to the LOCA transient. Results are encouraging mainly due to code capacity progression (resolution and models), which allows more and more complex physical phenomena to be treated, like turbulence flow and LOCA. (author)

  4. Method to moor an offshore operating vessel

    Energy Technology Data Exchange (ETDEWEB)

    Flory, J.F.

    1983-01-24

    A vessel such as a storage vessel is permanently moored, by means such as a yoke pivoted on the forecastle of the vessel, to a mooring leg, e.g. a riser or anchor chain, which is attached to a base located on the ocean floor. Mounted on the vessel is tension exsisting means, for example, counterweights, springs, winches, or the like, operably connected with the mooring leg for applying tension thereto such as by lifting the yoke. The top of the mooring leg is connected to the end of the yoke through a mooring swivel and a gimbaled mooring table or a universal joint. A fluid swivel may be located above the mooring table or about a load-carrying shaft connected to the mooring leg. 8 drawings.

  5. Biaxial Loading Tests for steel containment vessel

    Energy Technology Data Exchange (ETDEWEB)

    Miyagawa, T. [Nuclear Power Engineering Corp., Tokyo (Japan); Wright, D.J.; Arai, S.

    1999-07-01

    The Nuclear Power Engineering Corporation (NUPEC) has conducted a 1/10 scale of the steel containment vessel (SCV) test for the understanding of ultimate structural behavior beyond the design pressure condition. Biaxial Loading Tests were supporting tests for the 1/10 scale SCV model to evaluate the method of estimating failure conditions of thin steel plates under biaxial loading conditions. The tentative material models of SGV480 and SPV490 were obtained. And the behavior of SGV480 and SPV490 thin steel plates under biaxial loading conditions could be well simulated by FE-Analyses with the tentative material models and Mises constitutive law. This paper describes the results and the evaluations of these tests. (author)

  6. Biaxial Loading Tests for steel containment vessel

    International Nuclear Information System (INIS)

    Miyagawa, T.; Wright, D.J.; Arai, S.

    1999-01-01

    The Nuclear Power Engineering Corporation (NUPEC) has conducted a 1/10 scale of the steel containment vessel (SCV) test for the understanding of ultimate structural behavior beyond the design pressure condition. Biaxial Loading Tests were supporting tests for the 1/10 scale SCV model to evaluate the method of estimating failure conditions of thin steel plates under biaxial loading conditions. The tentative material models of SGV480 and SPV490 were obtained. And the behavior of SGV480 and SPV490 thin steel plates under biaxial loading conditions could be well simulated by FE-Analyses with the tentative material models and Mises constitutive law. This paper describes the results and the evaluations of these tests. (author)

  7. Stress analysis in a non axisymmetric loaded reactor pressure vessel

    International Nuclear Information System (INIS)

    Albuquerque, Levi Barcelos; Assis, Gracia Menezes V. de; Miranda, Carlos Alexandre J.; Cruz, Julio Ricardo B.; Mattar Neto, Miguel

    1995-01-01

    In this work we intend to present the stress analysis of a PWR vessel under postulated concentrated loads. The vessel was modeled with Axisymmetric solid 4 nodes harmonic finite elements with the use of the ANSYS program, version 5.0. The bolts connecting the vessel flanges were modeled with beam elements. Some considerations were made to model the contact between the flanges. The perforated part of the vessel tori spherical head was modeled (with reduced properties due to its holes) to introduce its stiffness and loads but was not within the scope of this work. The loading consists of some usual ones, as pressure, dead weight, bolts preload, seismic load and some postulated ones as concentrated loads, over the vessel, modeled by Fourier Series. The results in the axisymmetric model are taken in terms of linearized stresses, obtained in some circumferential positions and for each position, in some sections along the vessel. Using the ASME Code (Section III, Division 1, Sub-section NB) the stresses are within the allowable limits. In order to draw some conclusions about stress linearization, the membrane plus bending stresses (Pl + Pb) are obtained and compared in some sections, using three different methods. (author)

  8. Investigation of impulsively loaded pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N.; Cornwell, R.; Hanner, D.; Leichter, H.; Mohr, P.

    1963-10-15

    Explosion containment vessels for containing from 2,000 to 3,000 five ton nuclear explosions are considered. Analysis methods appear adequate and lowest weights using the most advanced materials available in the next five years are projected.None of these materials can be fabricated today and all require extensive development. Present material technology limits the choice of materials and defines the weight. The addition of safety factors and fixtures (nozzles, etc.) will add to this weight considerably, and may well radically alter the vessel response. Improvements in the strength weight ratios of metals and glasses over those considered in this report do not appear reasonable at this time. Winding schemes to utilize the high strength of steel wires and somehow maintain a reasonable thickness appear to offer the most promise. A `ductile` beryllium would of course offer vast improvement, but no indications that this is being developed have appeared and all presently known beryllium is much too brittle.

  9. Dynamic loads on reactor vessel components by low pressure waves

    International Nuclear Information System (INIS)

    Benkert, J.; Mika, C.; Stegemann, D.; Valero, M.

    1978-01-01

    Starting from the conservation theorems for mass and impulses the code DRUWE has been developed enabling the calculation of dynamic loads of the reactor shell on the basis of simplified assumptions for the first period shortly after rupture. According to the RSK-guidelines it can be assumed that the whole weld size is opened within 15 msec. This time-dependent opening of the fractured plane can be taken into account in the computer program. The calculation is composed in a way that for a reactor shell devided into cross and angle sections the local, chronological pressure and strength curves, the total dynamic load as well as the moments acting on the fastenings of the reactor shell can be calculated. As input data only geometrical details concerning the concept of the pressure vessel and its components as well as the effective subcooling of the fluid are needed. By means of several parameters the program can be operated in a way that the results are available in form of listings or diagrams, respectively, but also as card pile for further examinations, e.g. strength analysis. (orig./RW) [de

  10. Pressure vessels supported in the soil submitted to axissymetrical loads

    International Nuclear Information System (INIS)

    Gouvea, J.P. de; Bevilacqua, L.

    1982-01-01

    A pressure vessel, spherical segment or vertical cylinder, is supported in the soil and submitted to axissymetrical loads. The soil is considered as a semi-infinite elastic solid and the support as a lattice. The method of rigidity is used. (E.G.) [pt

  11. Shock loading of reactor vessel following hypothetical core disruptive accident

    International Nuclear Information System (INIS)

    Srinivas, G.; Doshi, J.B.

    1990-01-01

    Hypothetical Core Disruptive Accident (HCDA) has been historically considered as the maximum credible accident in Fast Breeder Reactor systems. Environmental consequences of such an accident depends to a great extent on the ability of the reactor vessel to maintain integrity during the shock loading following an HCDA. In the present paper, a computational model of the reactor core and the surrounding coolant with a free surface is numerical technique. The equations for conservation of mass, momentum and energy along with an equation of state are considered in two dimensional cylindrical geometry. The reactor core at the end of HCDA is taken as a bubble of hot, vaporized fuel at high temperature and pressure, formed at the center of the reactor vessel and expanding against the surrounding liquid sodium coolant. The free surface of sodium at the top of the vessel and the movement of the core bubble-liquid coolant interface are tracked by Marker and Cell (MAC) procedure. The results are obtained for the transient pressure at the vessel wall and also for the loading on the roof plug by the impact of the slug of liquid sodium. The computer code developed is validated against a benchmark experiment chosen to be ISPRA experiment reported in literature. The computer code is next applied to predict the loading on the Indian Prototype Fast Breeder Reactor (PFBR) being developed at Kalpakkam

  12. Integrating Multiple Autonomous Underwater Vessels, Surface Vessels and Aircraft into Oceanographic Research Vessel Operations

    Science.gov (United States)

    McGillivary, P. A.; Borges de Sousa, J.; Martins, R.; Rajan, K.

    2012-12-01

    Autonomous platforms are increasingly used as components of Integrated Ocean Observing Systems and oceanographic research cruises. Systems deployed can include gliders or propeller-driven autonomous underwater vessels (AUVs), autonomous surface vessels (ASVs), and unmanned aircraft systems (UAS). Prior field campaigns have demonstrated successful communication, sensor data fusion and visualization for studies using gliders and AUVs. However, additional requirements exist for incorporating ASVs and UASs into ship operations. For these systems to be optimally integrated into research vessel data management and operational planning systems involves addressing three key issues: real-time field data availability, platform coordination, and data archiving for later analysis. A fleet of AUVs, ASVs and UAS deployed from a research vessel is best operated as a system integrated with the ship, provided communications among them can be sustained. For this purpose, Disruptive Tolerant Networking (DTN) software protocols for operation in communication-challenged environments help ensure reliable high-bandwidth communications. Additionally, system components need to have considerable onboard autonomy, namely adaptive sampling capabilities using their own onboard sensor data stream analysis. We discuss Oceanographic Decision Support System (ODSS) software currently used for situational awareness and planning onshore, and in the near future event detection and response will be coordinated among multiple vehicles. Results from recent field studies from oceanographic research vessels using AUVs, ASVs and UAS, including the Rapid Environmental Picture (REP-12) cruise, are presented describing methods and results for use of multi-vehicle communication and deliberative control networks, adaptive sampling with single and multiple platforms, issues relating to data management and archiving, and finally challenges that remain in addressing these technological issues. Significantly, the

  13. The measured contribution of whipping and springing on the fatigue and extreme loading of container vessels

    Science.gov (United States)

    Storhaug, Gaute

    2014-12-01

    Whipping/springing research started in the 50'ies. In the 60'ies inland water vessels design rules became stricter due to whipping/springing. The research during the 70-90'ies may be regarded as academic. In 2000 a large ore carrier was strengthened due to severe cracking from North Atlantic operation, and whipping/springing contributed to half of the fatigue damage. Measurement campaigns on blunt and slender vessels were initiated. A few blunt ships were designed to account for whipping/springing. Based on the measurements, the focus shifted from fatigue to extreme loading. In 2005 model tests of a 4,400 TEU container vessel included extreme whipping scenarios. In 2007 the 4400 TEU vessel MSC Napoli broke in two under similar conditions. In 2009 model tests of an 8,600 TEU container vessel container vessel included extreme whipping scenarios. In 2013 the 8,100 TEU vessel MOL COMFORT broke in two under similar conditions. Several classification societies have published voluntary guidelines, which have been used to include whipping/springing in the design of several container vessels. This paper covers results from model tests and full scale measurements used as background for the DNV Legacy guideline. Uncertainties are discussed and recommendations are given in order to obtain useful data. Whipping/springing is no longer academic.

  14. 43 CFR 423.38 - Operating vessels on Reclamation waters.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Operating vessels on Reclamation waters... WATERBODIES Rules of Conduct § 423.38 Operating vessels on Reclamation waters. (a) You must comply with... Reclamation waters, and with any restrictions established by an authorized official. (b) You must not operate...

  15. Structural analysis of the ITER vacuum vessel from disruption loading with halo asymmetry

    International Nuclear Information System (INIS)

    Riemer, B.W.; Sayer, R.O.

    1996-01-01

    Static structural analyses of the ITER vacuum vessel were performed with toroidally asymmetric disruption loads. Asymmetric halo current conditions were assumed to modify symmetric disruption loads which resulted in net lateral loading on the vacuum vessel torus. Structural analyses with the asymmetric loading indicated significantly higher vessel stress and blanket support forces than with symmetric disruption loads. A recent change in the vessel support design which provided toroidal constraints at each mid port was found to be effective in reducing torus lateral movement and vessel stress

  16. Heat load imposed on reactor vessels during in-vessel retention of core melts

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Su-Hyeon; Chung, Bum-Jin, E-mail: bjchung@khu.ac.kr

    2016-11-15

    Highlights: • Angular heat load on reactor vessel by natural convection of oxide pool was measured. • High Ra was achieved by using mass transfer experiments based on analogy concept. • Measured Nusselt numbers agreed reasonably with the other existing studies. • Three different types of volumetric heat sources were compared. • They didn’t affect the heat flux of the top plate but affected those of the reactor vessel. - Abstract: We measured the heat load imposed on reactor vessels by natural convection of the oxide pool in severe accidents. Based on the analogy between heat and mass transfer, mass transfer experiments were performed using a copper sulfate electroplating system. A modified Rayleigh number of the order 10{sup 14} was achieved in a small facility with a height of 0.1 m. Three different types of volumetric heat sources were compared and the average Nusselt number of the curved surface was 39% lower, whereas in the case of the top plate was 6% higher than in previous studies with a two-dimensional geometry due to the high Sc value of this study. Reliable experimental data on the angular heat flux ratios were reported compared to those of the BALI and SIGMA CP facilities in terms of fluctuations and consistency.

  17. 36 CFR 3.8 - What vessel operations are prohibited?

    Science.gov (United States)

    2010-07-01

    .... (4) Operating a vessel in excess of flat wake speed within 100 feet of: (i) A downed water skier; (ii... the endangering of the life, limb, or property of a person(s) through the operator's lack of knowledge...

  18. Multi-scenario evaluation and specification of electromagnetic loads on ITER vacuum vessel

    International Nuclear Information System (INIS)

    Rozov, Vladimir; Martinez, J.-M.; Portafaix, C.; Sannazzaro, G.

    2014-01-01

    Highlights: • We present the results of multi-scenario analysis of EM loads on ITER vacuum vessel (VV). • The differentiation of models provides the economic way to perform big amount of calculations. • Functional approximation is proposed for distributed data/FE/numerical results specification. • Examples of specification of the load profiles by trigonometric polynomials (DHT) are given. • Principles of accounting for toroidal asymmetry at EM interactions in tokamak are considered. - Abstract: The electro-magnetic (EM) transients cause mechanical forces, which represent one of the most critical loads for the ITER vacuum vessel (VV). The paper is focused on the results of multi-scenario analysis and systematization of these EM loads, including specifically addressed pressures on shells and the net vertical force. The proposed mathematical model and computational technology, based on the use of integral parameters and operational analysis methods, enabled qualitative and quantitative analysis of the problem, time-efficient computations and systematic assessment of a large number of scenarios. The obtained estimates, found envelopes and peak values exemplify the principal loads on the VV and provide a database to support engineering load specifications. Special attention is given to the challenge of specification and documenting of the results in a form, suitable for using the data in engineering applications. The practical aspects of specification of distributed data, such as experimental and finite-element (FE) results, by analytical interpolants are discussed. The example of functional approximation of the load profiles by trigonometric polynomials based on discrete Hartley transform (DHT) is given

  19. Multi-scenario evaluation and specification of electromagnetic loads on ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Rozov, Vladimir, E-mail: vladimir.rozov@iter.org; Martinez, J.-M.; Portafaix, C.; Sannazzaro, G.

    2014-10-15

    Highlights: • We present the results of multi-scenario analysis of EM loads on ITER vacuum vessel (VV). • The differentiation of models provides the economic way to perform big amount of calculations. • Functional approximation is proposed for distributed data/FE/numerical results specification. • Examples of specification of the load profiles by trigonometric polynomials (DHT) are given. • Principles of accounting for toroidal asymmetry at EM interactions in tokamak are considered. - Abstract: The electro-magnetic (EM) transients cause mechanical forces, which represent one of the most critical loads for the ITER vacuum vessel (VV). The paper is focused on the results of multi-scenario analysis and systematization of these EM loads, including specifically addressed pressures on shells and the net vertical force. The proposed mathematical model and computational technology, based on the use of integral parameters and operational analysis methods, enabled qualitative and quantitative analysis of the problem, time-efficient computations and systematic assessment of a large number of scenarios. The obtained estimates, found envelopes and peak values exemplify the principal loads on the VV and provide a database to support engineering load specifications. Special attention is given to the challenge of specification and documenting of the results in a form, suitable for using the data in engineering applications. The practical aspects of specification of distributed data, such as experimental and finite-element (FE) results, by analytical interpolants are discussed. The example of functional approximation of the load profiles by trigonometric polynomials based on discrete Hartley transform (DHT) is given.

  20. 33 CFR 161.12 - Vessel operating requirements.

    Science.gov (United States)

    2010-07-01

    ....0′ N. extending eastward through the Golden Gate, and the navigable waters of San Francisco Bay and... safety beyond that provided by other means. The bridge-to-bridge navigational frequency, 156.650 MHz (Ch... Measures, and Operating Requirements § 161.12 Vessel operating requirements. (a) Subject to the exigencies...

  1. Lifting simulation of an offshore supply vessel considering various operating conditions

    Directory of Open Access Journals (Sweden)

    Dong-Hoon Jeong

    2016-06-01

    Full Text Available Recently, an offshore support vessel is being widely used to install an offshore structure such as a subsea equipment which is laid on its deck. The lifting operation which is one of the installation operations includes lifting off, lifting in the air, splash zone crossing, deep submerging, and finally landing of the structure with an offshore support vessel crane. There are some major considerations during this operation. Especially, when lifting off the structure, if operating conditions such as ocean environmental loads and hoisting (or lowering speed are bad, the excess of tension of wire ropes of the crane and the collision between the offshore support vessel and the structure can be occurred due to the relative motion between them. To solve this problem, this study performs the lifting simulation while the offshore support vessel installs the structure. The simulation includes the calculation of dynamic responses of the offshore support vessel and the equipment, including the wire tension and the collision detection. To check the applicability of the simulation, it is applied to some lifting steps by varying operating conditions. As a result, it is confirmed that the conditions affect the operability of those steps.

  2. Parametric model to estimate containment loads following an ex-vessel steam spike

    International Nuclear Information System (INIS)

    Lopez, R.; Hernandez, J.; Huerta, A.

    1998-01-01

    This paper describes the use of a relatively simple parametric model to estimate containment loads following an ex-vessel steam spike. The study was motivated because several PSAs have identified containment loads accompanying reactor vessel failures as a major contributor to early containment failure. The paper includes a detailed description of the simple but physically sound parametric model which was adopted to estimate containment loads following a steam spike into the reactor cavity. (author)

  3. Load Extrapolation During Operation for Wind Turbines

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    2008-01-01

    In the recent years load extrapolation for wind turbines has been widely considered in the wind turbine industry. Loads on wind turbines during operations are normally dependent on the mean wind speed, the turbulence intensity and the type and settings of the control system. All these parameters...... must be taken into account when characteristic load effects during operation are determined. In the wind turbine standard IEC 61400-1 a method for load extrapolation using the peak over threshold method is recommended. In this paper this method is considered and some of the assumptions are examined...

  4. Marine Vessel Models in Changing Operational Conditions - A Tutorial

    DEFF Research Database (Denmark)

    Perez, Tristan; Sørensen, Asgeir; Blanke, Mogens

    2006-01-01

    conditions (VOC). However, since marine systems operate in changing VOCs, there is a need to adapt the models. To date, there is no theory available to describe a general model valid across different VOCs due to the complexity of the hydrodynamic involved. It is believed that system identification could......This tutorial paper provides an introduction, from a systems perspective, to the topic of ship motion dynamics of surface ships. It presents a classification of parametric models currently used for monitoring and control of marine vessels. These models are valid for certain vessel operational...

  5. Structural analysis of the ITER Vacuum Vessel regarding 2012 ITER Project-Level Loads

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, J.-M., E-mail: jean-marc.martinez@live.fr [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Jun, C.H.; Portafaix, C.; Choi, C.-H.; Ioki, K.; Sannazzaro, G.; Sborchia, C. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Cambazar, M.; Corti, Ph.; Pinori, K.; Sfarni, S.; Tailhardat, O. [Assystem EOS, 117 rue Jacquard, L' Atrium, 84120 Pertuis (France); Borrelly, S. [Sogeti High Tech, RE2, 180 rue René Descartes, Le Millenium – Bat C, 13857 Aix en Provence (France); Albin, V.; Pelletier, N. [SOM Calcul – Groupe ORTEC, 121 ancien Chemin de Cassis – Immeuble Grand Pré, 13009 Marseille (France)

    2014-10-15

    Highlights: • ITER Vacuum Vessel is a part of the first barrier to confine the plasma. • ITER Vacuum Vessel as Nuclear Pressure Equipment (NPE) necessitates a third party organization authorized by the French nuclear regulator to assure design, fabrication, conformance testing and quality assurance, i.e. Agreed Notified Body (ANB). • A revision of the ITER Project-Level Load Specification was implemented in April 2012. • ITER Vacuum Vessel Loads (seismic, pressure, thermal and electromagnetic loads) were summarized. • ITER Vacuum Vessel Structural Margins with regards to RCC-MR code were summarized. - Abstract: A revision of the ITER Project-Level Load Specification (to be used for all systems of the ITER machine) was implemented in April 2012. This revision supports ITER's licensing by accommodating requests from the French regulator to maintain consistency with the plasma physics database and our present understanding of plasma transients and electro-magnetic (EM) loads, to investigate the possibility of removing unnecessary conservatism in the load requirements and to review the list and definition of incidental cases. The purpose of this paper is to present the impact of this 2012 revision of the ITER Project-Level Load Specification (LS) on the ITER Vacuum Vessel (VV) loads and the main structural margins required by the applicable French code, RCC-MR.

  6. Test of 6-in.-thick pressure vessels. Series 3: intermediate test vessel V-7A under sustained loading

    International Nuclear Information System (INIS)

    Bryan, R.H.; Cate, T.M.; Holz, P.P.; King, T.A.; Merkle, J.G.; Robinson, G.C.; Smith, G.C.; Smith, J.E.; Whitman, G.D.

    1978-01-01

    HSST intermediate test vessel V-7 was repaired after being tested hydrostatically to leakage and was retested pneumatically as vessel V-7A. Except for the method of applying the load, the conditions in both tests were nearly identical. In each case, a sharp outside surface flaw 547 mm long (18 in.) by about 135 mm deep (5.3 in.) was prepared in the 152-mm-thick (6-in.) test cylinder of A533, grade B, class 1 steel. The inside surface of vessel V-7A was sealed in the region of the flaw by a thin metal patch so that pressure could be sustained after rupture. Vessel V-7A failed by rupture of the flaw ligament without burst, as expected. Rupture occurred at 144.3 MPa (20.92 ksi), after which pressure was sustained for 30 min without any indication of instability. The rupture pressure of vessel V-7A was about 2 percent less than that of vessel V-7

  7. Load-following operation of PWR plants

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jong Hwa; Oh, Soo Yul; Koo, Yang Hyun; Lee, Jae Han [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1993-12-01

    The load-following operation of nuclear power plants will become inevitable due to the increased nuclear share in the total electricity generation. As a groundwork for the load-following capability of the Korean next generation PWRs, the state-of-the-art has been reviewed. The core control principles and methods are the main subject in this review as well as the impact of load-following operations on the fuel performance and on the mechanical integrity of components. To begin with, it was described what the load-following operation is and in what view point the technology should be reviewed. Afterwards the load-following method, performance and problems in domestic 900 MWe class PWRs were discussed, and domestic R and D works were summarized. Foreign technologies were also reviewed. They include Mode G and Mode X of Foratom, D and L bank method of KWU, the method using PSCEA of ABB-CE, and MSHIM of Westinghouse. The load-following related special features of Foratom`s N4 plant, KWU`s plants, ABB-CE`s Systems 80+, and Westinghouse`s AP600 were described in each technology review. The review concluded that the capability of N4 plant with Mode X is the best and the methods in System, 80+ and AP600 would require verifications for the continued and usual load-following operation. It was recommended that the load-following operation experiences in domestic PWRs under operation be required to settle down the capability for the future. In addition, a more enhanced technology is required for the Korean next generation PWR regardless what the reference plant concept is. 30 figs., 19 tabs., 75 refs. (Author).

  8. 46 CFR 180.202 - Survival craft-vessels operating on oceans routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft-vessels operating on oceans routes. 180... VESSELS (UNDER 100 GROSS TONS) LIFESAVING EQUIPMENT AND ARRANGEMENTS Number and Type of Survival Craft § 180.202 Survival craft—vessels operating on oceans routes. (a) Each vessel certificated to operate on...

  9. Nonlinear response of vessel walls due to short-time thermomechanical loading

    International Nuclear Information System (INIS)

    Pfeiffer, P.A.; Kulak, R.F.

    1994-01-01

    Maintaining structural integrity of the reactor pressure vessel (RPV) during a postulated core melt accident is an important safety consideration in the design of the vessel. This study addresses the failure predictions of the vessel due to thermal and pressure loadings fro the molten core debris depositing on the lower head of the vessel. Different loading combinations were considered based on the dead load, yield stress assumptions, material response and internal pressurization. The analyses considered only short term failure (quasi static) modes, long term failure modes were not considered. Short term failure modes include plastic instabilities of the structure and failure due to exceeding the failure strain. Long term failure odes would be caused by creep rupture that leads to plastic instability of the structure. Due to the sort time durations analyzed, creep was not considered in the analyses presented

  10. Load Management in District Heating Operation

    OpenAIRE

    Li, Hongwei; Wang, Stephen Jia

    2015-01-01

    Smooth operation of district heating system will avoid installation of expensive peak heat boilers, improve plant partial load performance, increase the system redundancy for further network expansion and improve its resilience to ensuresecurity of supply during severe heating seasons. The peak heating load can be reduced through building demand side management. The building thermal mass can be used to shift the heating supply under the circumstance withoutjeopardizing the consumer thermal co...

  11. Structural Loading of Cross Deck Connections for Trimaran Vessels

    National Research Council Canada - National Science Library

    Rhoads, Jason

    2004-01-01

    ...: longitudinal bending, transverse bending, torsional bending, spreading and squeezing of hulls, inner and outer hull slam pressures, wet deck slam pressures, loading from ship's motions, and whipping of slender hulls...

  12. Lower bounds of collapse loads in axisymmetrical vessels

    International Nuclear Information System (INIS)

    Fonseca Neto, J. de D.; Ebecken, N.F.F.

    1981-01-01

    The rigid-plastic limit analysis of shells of revolution subject to rotationally symmetric loadings, is presented. After assembling the finite elements, the limit analysis program is reduced to a simple application of the non-linear programming technique, where the sequential unconstrained minimization technique (SUMT) is utilized for the statically admissible approach. Lower bounds of the collapse loads are presented and compared with the results described in the literature. (Author) [pt

  13. Assessment of integrity for the pressure vessel internals of PWRs under blowdown loadings

    International Nuclear Information System (INIS)

    Geiss, M.; Benner, J.; Ludwig, A.

    1984-01-01

    In safety analysis of pressurized water reactors the loss-of-coolant accident plays a central role. Thereby a sudden break of a cold primary coolant pipe close to the reactor pressure vessel is postulated. The sudden pressure release of the primary system (blowdown) causes high dynamic loading on the pressure vessel internals. The resulting deformations must not impair shut down of the reactor and decay heat removal in an inadmissible way. For this assessment a blowdown analysis for a 1300 MW pressurized water reactor is carried out. These investigations are completed with a detailed stress analysis for the highly loaded core barrel clamping. The results show that the reactor pressure vessel internals are able to withstand blowdown loading. Even in case of a sudden and complete break of the primary coolant pipe the loading has to be twice as high to endanger the structural integrity. (orig.) [de

  14. Load bearing capacities and elastic-plastic behavior of reactor vessel internals

    International Nuclear Information System (INIS)

    Watanabe, Keita; Nagase, Ryuichi

    2017-01-01

    Radial Support Keys (RSKs) are installed at the bottom of Reactor Vessel Internal (RVI) of Pressurized Water Reactor (PWR) and fit into Core Support Lugs of Reactor Pressure Vessel (RPV). This structure provides reactor core horizontal support and transmits the loads between RVI and RPV. RSK is one of the critical parts of RVI from the view point of earthquake-proof safety. In order to assure the structural integrity of Nuclear Reactor in case of massive earthquake, load bearing capacities of RSK are confirmed by static loading tests with reduced-scale mockups. In addition, collapse loads of actual components calculated by Limit Analyses are conservative enough compared to the load bearing capacities confirmed by the test. Thus, the methodology to calculate collapse load by Limit Analysis is applicable to evaluation of structural integrity for RSK. (author)

  15. Thermal and mechanical cyclic loading of thick spherical vessels made of transversely isotropic materials

    International Nuclear Information System (INIS)

    Komijani, M.; Mahbadi, H.; Eslami, M.R.

    2013-01-01

    The aim of this paper is to obtain the dependency of the ratcheting, reversed plasticity, or shakedown behavior of spherical vessels made of some anisotropic materials to the stress category of imposed cyclic loading. The Hill anisotropic yield criterion with the kinematic hardening theories of plasticity based on the Prager and Armstrong–Frederick models are used to predict the yield of the vessel and obtain the plastic strains. An iterative numerical method is used to simulate the cyclic loading behavior of the structure. The effect of mean and amplitude of the mechanical and thermal loads on cyclic behavior and ratcheting rate of the vessel is investigated respectively. The ratcheting rate for the vessels made of transversely isotropic material is evaluated for the various ratios of anisotropy. -- Highlights: ► Cyclic loading analysis of anisotropic spheres is assessed. ► Using the Prager model results in ratcheting. ► Armstrong-Frederick model predicts ratcheting for load controlled cyclic loadings. ► The A-F model predicts ratcheting to a stabilized cycle for thermal loadings

  16. Evaluation of SMART load follow operation capability

    International Nuclear Information System (INIS)

    Song, Jae Seung; Zee, Sung Quun

    1998-07-01

    The daily load follow operation capability of SMART, which is 330 MWth integral reactor with boron free operation concept, was evaluated. In the boron free operation core the axial offset(AO) can not be limited or limited by wider range than the typical PWR that uses soluble boron. Current SMART conceptual core design does not have the limit for the axial offset and the operation is limited by three dimensional local power peak. In this report, the capability of load follow operation is evaluated for 14-2-6-2 daily load follow by 50% power reduction that is very typical in the large commercial power reactors. The cycle length of SMART is limited by three dimensional local power peak and the nominal axial power distribution is top skewed at the end of cycle. When the power returns to 100%, control rod should be withdrawn for the compensation of reactivity decrease due to the xenon buildup. The control rod withdrawal results in the increase of three dimensional local power peak. To solve this problem, an operation strategy for the control of local peak. To solve this problem, an operation strategy for the control of local peak was established and it was shown that the strategy is effective in controlling the local peak less than target value of the three dimensional local power peak. (author). 7 refs., 5 tabs., 13 figs

  17. Fourier series analysis of a cylindrical pressure vessel subjected to axial end load and external pressure

    International Nuclear Information System (INIS)

    Brar, Gurinder Singh; Hari, Yogeshwar; Williams, Dennis K.

    2013-01-01

    This paper presents the comparison of a reliability technique that employs a Fourier series representation of random axisymmetric and asymmetric imperfections in a cylindrical pressure vessel subjected to an axial end load and external pressure, with evaluations prescribed by the ASME Boiler and Pressure Vessel Code, Section VIII, Division 2 Rules. The ultimate goal of the reliability technique described herein is to predict the critical buckling load associated with the subject cylindrical pressure vessel. Initial geometric imperfections are shown to have a significant effect on the calculated load carrying capacity of the vessel. Fourier decomposition was employed to interpret imperfections as structural features that can be easily related to various other types of defined imperfections. The initial functional description of the imperfections consists of an axisymmetric portion and a deviant portion, which are availed in the form of a double Fourier series. Fifty simulated shells generated by the Monte Carlo technique are employed in the final prediction of the critical buckling load. The representation of initial geometrical imperfections in the cylindrical pressure vessel requires the determination of respective Fourier coefficients. Multi-mode analyses are expanded to evaluate a large number of potential buckling modes for both predefined geometries in combination with asymmetric imperfections as a function of position within the given cylindrical shell. The probability of the ultimate buckling stress exceeding a predefined threshold stress is also calculated. The method and results described herein are in stark contrast to the “knockdown factor” approach as applied to compressive stress evaluations currently utilized in industry. Further effort is needed to improve on the current design rules regarding column buckling of large diameter pressure vessels subjected to an axial end load and external pressure designed in accordance with ASME Boiler and

  18. Ultimate limit states of steel containment vessel under earthquake loadings

    International Nuclear Information System (INIS)

    Akiyama, Hiroshi; Yuhara, Tetsuo; Shimizu, Seiichi; Hayashi, Kazutoshi; Takahashi, Tadao.

    1986-01-01

    The limit state induced by buckling of cylindrical steel structures under earthquake loadings was investigated from the standpoint of energy concept. A number of the buckling test of cylindrical steel shell structures has been made, which showed that they have a stable load-displacement relation and adequate deformation capacities beyond the buckling. The authors are proposing that the energy input imparted by strong earthquakes to buckled structures and the deformation capacity in post-buckling are suitable indices for seismic resistance of the cylindrical steel shell structures because the buckling does not cause the structure immediately to collapse in the case of such repeated loading as earthquake motions. The purpose of this study is to investigate the energy input to buckled cylindrical steel structures with an increase in the intensity of earthquake motions. A series of nonlinear dynamic analyses were performed under various types of earthquake records by using a hysteresis loop, including buckling, which was derived from the buckling tests. The limit state could be defined as the state in which the deformation of and the energy input into buckled structures increase divergently when the intensity of the earthquake excitation exceeds a certain value. The results obtained in this paper are intended to be adopted to the limit state in the post-buckling region to evaluate the margin of safety against the buckling resistance of cylindrical steel structures under strong earthquake loadings. (author)

  19. 46 CFR 154.409 - Dynamic loads from vessel motion.

    Science.gov (United States)

    2010-10-01

    ... in length and is an analysis by the following formulae that corresponds to a 10−8 probability level... EC02FE91.086 (d) If a cargo tank is designed to avoid fatigue, the dynamic loads determined under paragraph...

  20. Changes in the vessels following aorto-coronary bypass operation

    International Nuclear Information System (INIS)

    Goebel, N.; Pfluger, N.; Speiser, K.; Turina, M.; Rothlin, M.; Zurich Univ.; Zurich Univ.

    1983-01-01

    In a prospective study (238 men, mean age 53 years) the changes of the native vessels were studied 3 months after a-c-bypass operation and 5 months after preop. angiography. Progression was defined as increase of stenoses of at least 20% or new total occlusion. Progression was significantly more frequent in vessels with than without bypass and was located proximally to the anastomoses in most cases, less frequently at the anastomoses and very rarely distally to the anastomoses. Proximal progression was significantly more frequent with patent than with occluded bypasses. Stenoses at the anastomoses were significantly more frequent with occluded than with patent bypasses. Stenoses of higher degrees hat a stonger tendency for progression than slighter stenoses. Regression was rare and nearly always caused by surgery. (orig.) [de

  1. In vivo experimental study on laser welded ICG-loaded chitosan patches for vessel repair

    Science.gov (United States)

    Rossi, Francesca; Matteini, Paolo; Esposito, Giuseppe; Albanese, Alessio; Puca, Alfredo; Maira, Giulio; Rossi, Giacomo; Pini, Roberto

    2011-03-01

    Laser welding of microvessels provides several advantages over conventional suturing techniques: surgical times reduction, vascular healing process improvement, tissue damage reduction. We present the first application of biopolymeric patches in an in vivo laser assisted procedure for vessel repair. The study was performed in 20 New Zealand rabbits. After anesthesia, a 3-cm segment of the right common carotid artery was exposed and clamped proximally and distally. A linear lesion 3 mm in length was carried out. We used a diode laser emitting at 810 nm and equipped with a 300 μm diameter optical fiber. To close the cut, ICG-loaded chitosan films were prepared: chitosan is characterized by biodegradability, biocompatibility, antimicrobial, haemostatic and wound healing-promoting activity. ICG is an organic chromophore commonly used in the laser welding procedures to mediate the photothermal conversion at the basis of the welding effect. The membranes were used to wrap the whole length of the cut, and then they were welded in the correct position by delivering single laser spots to induce local patch/tissue adhesion. The result is an immediate closure of the wound, with no bleeding at clamps release. The animals were observed during follow-up and sacrificed after 2, 7, 30 and 90 days. All the repaired vessels were patent, no bleeding signs were documented. The carotid samples underwent histological examinations. The advantages of the proposed technique are: simplification of the surgical procedure and shortening of the operative time; good strength of the vessel repair; decreased foreign-body reaction, reduced inflammatory response and improved vascular healing process.

  2. Modelling Vessel Traffic Service to understand resilience in everyday operations

    International Nuclear Information System (INIS)

    Praetorius, Gesa; Hollnagel, Erik; Dahlman, Joakim

    2015-01-01

    Vessel Traffic Service (VTS) is a service to promote traffic fluency and safety in the entrance to ports. This article's purpose has been to explore everyday operations of the VTS system to gain insights in how it contributes to safe and efficient traffic movements. Interviews, focus groups and an observation have been conducted to collect data about everyday operations, as well as to grasp how the VTS system adapts to changing operational conditions. The results show that work within the VTS domain is highly complex and that the two systems modelled realise their services vastly differently, which in turn affects the systems' ability to monitor, respond and anticipate. This is of great importance to consider whenever changes are planned and implemented within the VTS domain. Only if everyday operations are properly analysed and understood, it can be estimated how alterations to technology and organisation will affect the overall system performance

  3. Load Management in District Heating Operation

    DEFF Research Database (Denmark)

    Li, Hongwei; Wang, Stephen Jia

    2015-01-01

    Smooth operation of district heating system will avoid installation of expensive peak heat boilers, improve plant partial load performance, increase the system redundancy for further network expansion and improve its resilience to ensure security of supply during severe heating seasons. The peak...... heating load can be reduced through building demand side management. The building thermal mass can be used to shift the heating supply under the circumstance without jeopardizing the consumer thermal comfort. In this paper, the multi-agent framework is applied to a simplified building dynamic model...

  4. Ultimate load design and testing of a cylindrical prestressed concrete vessel

    International Nuclear Information System (INIS)

    Stefanou, G.D.

    1982-01-01

    The object of this research was to design, construct and test to failure a prestressed concrete pressure vessel model that could be used to investigate the behavior of a full scale structure underworking and ultimate load. The properties and the design of the model was based generally on full scale vessels already constructed to house the nuclear reactors used in atomic power stations. To design the model the ultimate load approach was adopted throughout. All load factors associated with the prestressing have been defined and kept to a minimum in order that the vessel's behavior may be predicted. The tests on the vessel were carried out first on the elastic range to observe its behavior at working load and then at the ultimate range to observe the modes of failure and compare the actual results in both cases with the predicted values. Although full agreement between observed results and predicted values was not obtained, the conclusions drawn from the study were useful for the design of full scale vessels. (author)

  5. Revisiting the reactor pressure vessel for long-time operation

    International Nuclear Information System (INIS)

    Lapena, J.; Serrano, M.; Diego, G. de; Hernandez Mayoral, M.

    2013-01-01

    The reactor pressure vessel (RPV) is one of the key components of nuclear power plants, especially for long time operation. It is a non-replaceable component, at least with current technology. the structural integrity of the vessel is evaluated within called monitoring programs where the degradation of the mechanical properties due to neutron irradiation is determined. From the first designs of the RPVs and monitoring programs in the years 60-70 currently still in force, there have been major advances in the understanding of radiation damage and methods of evaluation. Thus, it is recommended the use of forgings instead of plates in the construction of the RPVs in order to reduce the number of welds, more sensitive to neutron irradiation, and using starting materials with less content of impurities, particularly copper. To evaluate the embrittlement of RPVs the Master Curve methodology is currently used, through the testing of the charpy specimens from the surveillance capsules, to determine the fracture toughness. This article summarizes the last activities of CIEMAT into the European research projects LONGIIFE and PERFORM60, about the knowledge of radiation damage in materials with low copper content, traditionally considered less sensitive to irradiation, and the use of the Master Curve in advanced surveillance programs. The activities related to the problems associated with the use of large forging, such as the appearance of hydrogen flakes in the vessel of Doel 3, and its implications, are also presented. (Author)

  6. 46 CFR 180.205 - Survival craft-vessels operating on limited coastwise routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft-vessels operating on limited coastwise... Craft § 180.205 Survival craft—vessels operating on limited coastwise routes. (a) Except as allowed by... survival craft required by § 180.204(d). (e) Each vessel certificated to operate on a limited coastwise...

  7. 46 CFR 180.207 - Survival craft-vessels operating on lakes, bays, and sounds routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft-vessels operating on lakes, bays, and... Survival Craft § 180.207 Survival craft—vessels operating on lakes, bays, and sounds routes. (a) Except as... warm water is not required to carry survival craft. (d) A vessel certificated to operate on lakes, bays...

  8. Stresses and displacements in vessels due to loads imposed by single and multiple piping attachments

    International Nuclear Information System (INIS)

    Wong, F.M.G.; Craft, W.J.; East, G.H.

    1985-01-01

    The Fourier solution for thin shell equations models pressure vessels as continuous simply connected surfaces with local loads. The technique allows placement of tractions with combinations of radial, shear, and axial components. Unlike Bijlaard, the solution in this paper includes loads placed at any position along the cylinder. Stiffness and the enhanced load-carrying capacity that internal pressure gives to thin vessels can be simulated. Numerical convergence problems are reduced by an improved displacement-load algorithm, and by use of load sites that allow the circular functions to be compactly grouped. A variety of loading distributions may be analyzed including large and small nozzles near and away from centerlines. Both rectangular and circular attachments are simulated. Through superposition, multiple attachments with their own loads may be examined. The attachments to the vessel may be either rigid or soft. A comparison to analytical results from Bijlaard shows excellent agreement. Comparisons with experimental tests on an API-650 nozzle on a storage tank are in good agreement. Variations between experimental and calculated results are primarily caused by assuming a simply supported base in the calculation, whereas in the experimental test, the base is more nearly fixed

  9. Dynamic load effects on gate valve operability

    International Nuclear Information System (INIS)

    Steele, R. Jr.; MacDonald, P.E.; Arendts, J.G.

    1986-01-01

    The Idaho National Engineering Laboratory (INEL) participated in an internationally sponsored seismic research program conducted at the decommissioned Heissdampfreaktor (HDR) located in the Federal Republic of Germany. An existing piping system was modified by installation of an 8-in., naturally aged, motor-operated gate valve from a US nuclear power plant and a piping support system of US design. Six other piping support systems of varying flexibility from stiff to flexible were also installed at various times during the tests. Additional valve loadings included internal hydraulic loads and, during one block of tests, elevated temperature. The operability and integrity of the aged gate valve and the dynamic response of the various piping support system were measured during 25 representative seismic events

  10. PHM Enabled Autonomous Propellant Loading Operations

    Science.gov (United States)

    Walker, Mark; Figueroa, Fernando

    2017-01-01

    The utility of Prognostics and Health Management (PHM) software capability applied to Autonomous Operations (AO) remains an active research area within aerospace applications. The ability to gain insight into which assets and subsystems are functioning properly, along with the derivation of confident predictions concerning future ability, reliability, and availability, are important enablers for making sound mission planning decisions. When coupled with software that fully supports mission planning and execution, an integrated solution can be developed that leverages state assessment and estimation for the purposes of delivering autonomous operations. The authors have been applying this integrated, model-based approach to the autonomous loading of cryogenic spacecraft propellants at Kennedy Space Center.

  11. 46 CFR 180.206 - Survival craft-vessels operating on Great Lakes routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft-vessels operating on Great Lakes routes... Craft § 180.206 Survival craft—vessels operating on Great Lakes routes. (a) Except as allowed by... with the survival craft required by § 180.205 (a) through (e), as appropriate. (b) Each vessel...

  12. 46 CFR 117.207 - Survival craft-vessels operating on lakes, bays, and sounds routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Survival craft-vessels operating on lakes, bays, and... 49 PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Number and Type of Survival Craft § 117.207 Survival craft—vessels operating on lakes, bays, and sounds routes. (a) Each vessel with overnight...

  13. 46 CFR 180.208 - Survival craft-vessels operating on rivers routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft-vessels operating on rivers routes. 180... VESSELS (UNDER 100 GROSS TONS) LIFESAVING EQUIPMENT AND ARRANGEMENTS Number and Type of Survival Craft § 180.208 Survival craft—vessels operating on rivers routes. (a) Except as allowed by paragraphs (c), (d...

  14. 46 CFR 117.208 - Survival craft-vessels operating on rivers routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Survival craft-vessels operating on rivers routes. 117... LIFESAVING EQUIPMENT AND ARRANGEMENTS Number and Type of Survival Craft § 117.208 Survival craft—vessels... vessel certificated to operate on a rivers route in warm water is not required to carry survival craft...

  15. A system for rotatably mounting a vessel to a loading buoy. System for dreibar tilkopling av et flytende farty til en lastebye

    Energy Technology Data Exchange (ETDEWEB)

    Breivik, K.; Smedal, A.; Syvertsen, K.

    1994-07-04

    The invention relates to a system for rotatable mounting of a floating vessel to a submerged loading/unloading buoy which is anchored to the sea bed. The buoy is adapted to be introduced into and fastened in a releasable manner in a submerged downwardly open receiving space in the vessel, and is during operation connected to at least one transfer line and forming a transfer connection between this line and a tube system on the vessel. The buoy comprises an outer member which is arranged to be rigidly fastened in the receiving space, and a central inner member which is rotatably mounted in the outer member, so that the vessel is able to turn about the central member when the buoy is fastened in the receiving space. Further, the upper end of the central member is connected to the tube system of the vessel through a swivel means and through at least one flexible joint means respectively. 3 figs.

  16. Filament wound pressure vessels with load sharing liners for space shuttle orbiter applications

    International Nuclear Information System (INIS)

    Ecord, G.M.

    1976-01-01

    Early in the development of orbiter propulsion and environmental control subsystems it was recognized that use of overwrapped pressure vessels with load sharing liners may provide significant weight savings for high pressure gas containment. A program is described which was undertaken by Rockwell International to assess the utility for orbiter applications of titanium 6Al--4V and Inconel 718 liners overwrapped with Kevlar fibers. Also briefly described are programs administered by the NASA Lewis Research Center to evaluate cryoformed steel liners overwrapped with Kevlar fibers and to establish a method that can guarantee cyclic life of the vessels

  17. Cyclic loading of thick vessels based on the Prager and Armstrong-Frederick kinematic hardening models

    International Nuclear Information System (INIS)

    Mahbadi, H.; Eslami, M.R.

    2006-01-01

    The aim of this paper is to relate the type of stress category in cyclic loading to ratcheting or shakedown behaviour of the structure. The kinematic hardening theory of plasticity based on the Prager and Armstrong-Frederick models is used to evaluate the cyclic loading behaviour of thick spherical and cylindrical vessels under load and deformation controlled stresses. It is concluded that kinematic hardening based on the Prager model under load and deformation controlled conditions, excluding creep, results in shakedown or reversed plasticity for spherical and cylindrical vessels with the isotropy assumption of the tension/compression curve. Under an anisotropy assumption of the tension/compression curve, this model predicts ratcheting. On the other hand, the Armstrong-Frederick model predicts ratcheting under load controlled cyclic loading and reversed plasticity for deformation controlled stress. The interesting conclusion is that the Armstrong-Frederick model is well capable to predict the experimental data under the assumed type of stresses, wherever experimental data are available

  18. Electromagnetic loads and structural response of the CIT [Compact Ignition Tokamak] vacuum vessel to plasma disruptions

    International Nuclear Information System (INIS)

    Salem, S.L.; Listvinsky, G.; Lee, M.Y.; Bailey, C.

    1987-01-01

    Studies of the electromagnetic loads produced by a variety of plasma disruptions, and the resulting structural effects on the compact Ignition Tokamak (CIT) vacuum vessel (VV), have been performed to help optimize the VV design. A series of stationary and moving plasmas, with disruption rates from 0.7--10.0 MA/ms, have been analyzed using the EMPRES code to compute eddy currents and electromagnetic pressures, and the NASTRAN code to evaluate the structural response of the vacuum vessel. Key factors contributing to the magnitude of EM forces and resulting stresses on the vessel have been found to include disruption rate, and direction and synchronization of plasma motion with the onset of plasma current decay. As a result of these analyses, a number of design changes have been made, and design margins for the present 1.75 meter design have been improved over the original CIT configuration. 1 ref., 10 figs., 4 tabs

  19. Safety assessment of in-vessel vapor explosion loads in next generation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kwang Hyun; Cho, Jong Rae; Choi, Byung Uk; Kim, Ki Yong; Lee, Kyung Jung [Korea Maritime University, Busan (Korea); Park, Ik Kyu [Seoul National University, Seoul (Korea)

    1998-12-01

    A safety assessment of the reactor vessel lower head integrity under in-vessel vapor explosion loads has been performed. The premixing and explosion calculations were performed using TRACER-II code. Using the calculated explosion pressures imposed on the lower head inner wall, strain calculations were performed using ANSYS code. The explosion analyses show that the explosion impulses are not altered significantly by the uncertain parameters of triggering location and time, fuel and vapor volume fractions in uniform premixture bounding calculations within the conservative ranges. Strain analyses using the calculated pressure loads on the lower head inner wall show that the vapor explosion-induced lower head failure is physically unreasonable. The static analysis using the conservative explosion-end pressure of 7,246 psia shows that the maximum equivalent strain is 4.3% at the bottom of lower head, which is less than the allowable threshold value of 11%. (author). 24 refs., 40 figs., 3 tabs.

  20. Upper and Lower Bound Limit Loads for Thin-Walled Pressure Vessels Used for Aerosol Cans

    Directory of Open Access Journals (Sweden)

    Stephen John Hardy

    2009-01-01

    Full Text Available The elastic compensation method proposed by Mackenzie and Boyle is used to estimate the upper and lower bound limit (collapse loads for one-piece aluminium aerosol cans, which are thin-walled pressure vessels subjected to internal pressure loading. Elastic-plastic finite element predictions for yield and collapse pressures are found using axisymmetric models. However, it is shown that predictions for the elastic-plastic buckling of the vessel base require the use of a full three-dimensional model with a small unsymmetrical imperfection introduced. The finite element predictions for the internal pressure to cause complete failure via collapse fall within the upper and lower bounds. Hence the method, which involves only elastic analyses, can be used in place of complex elastic-plastic finite element analyses when upper and lower bound estimates are adequate for design purposes. Similarly, the lower bound value underpredicts the pressure at which first yield occurs.

  1. 36 CFR 3.15 - What is the maximum noise level for the operation of a vessel?

    Science.gov (United States)

    2010-07-01

    ... level for the operation of a vessel? 3.15 Section 3.15 Parks, Forests, and Public Property NATIONAL PARK... level for the operation of a vessel? (a) A person may not operate a vessel at a noise level exceeding... vessel is being operated in excess of the noise levels established in paragraph (a) of this section may...

  2. Effect of radiation damage on operating safety of steel pressure vessels of nuclear reactors

    International Nuclear Information System (INIS)

    Vacek, M.; Havel, S.; Stoces, B.; Brumovsky, M.

    1980-01-01

    The effects are assessed of the environment upon mechanical properties of steel used generally for pressure vessels of light water nuclear reactors. Changes caused by radiation affect the reliability of vessels. Deterioration of steel properties is mainly due to neutron radiation. The article deals with factors bearing upon damage and with methods allowing to evaluate the reliability of vessels and predict their service life. Operating reliability of vessels is very unfavourably affected by planned and accidental reactor transients. (author)

  3. Active cooling system for Tokamak in-vessel operation manipulator

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Jianjun, E-mail: yuanjj@sjtu.edu.cn; Chen, Tan; Li, Fashe; Zhang, Weijun; Du, Liang

    2015-10-15

    Highlights: • We summarized most of the challenges of fusion devices to robot systems. • Propose an active cooling system to protect all of the necessary components. • Trial design test and theoretical analysis were conducted. • Overall implementation of the active cooling system was demonstrated. - Abstract: In-vessel operation/inspection is an indispensable task for Tokamak experimental reactor, for a robot/manipulator is more capable in doing this than human being with more precise motion and less risk of damaging the ambient equipment. Considering the demanding conditions of Tokamak, the manipulator should be adaptable to rapid response in the extreme conditions such as high temperature, vacuum and so on. In this paper, we propose an active cooling system embedded into such manipulator. Cameras, motors, gearboxes, sensors, and other mechanical/electrical components could then be designed under ordinary conditions. The cooling system cannot only be a thermal shield since the components are also heat sources in dynamics. We carry out a trial test to verify our proposal, and analyze the active cooling system theoretically, which gives a direction on the optimization by varying design parameters, components and distribution. And based on thermal sensors monitoring and water flow adjusting a closed-loop feedback control of temperature is added to the system. With the preliminary results, we believe that the proposal gives a way to robust and inexpensive design in extreme environment. Further work will concentrate on overall implementation and evaluation of this cooling system with the whole inspection manipulator.

  4. Evaluation of temperature distribution in a containment vessel during operation

    International Nuclear Information System (INIS)

    Utanohara, Yoichi; Murase, Michio; Yanagi, Chihiro; Masui, Akihiro; Inomata, Ryo; Kamiya, Yuji

    2012-01-01

    For safety analysis of the containment vessel (CV) in a nuclear power plant, the average temperature of the gas phase in the CV during operation is used as an initial condition. An actual CV, however, has a temperature distribution, which makes the estimation of the average temperature difficult. Numerical simulation seems to be useful for the average temperature estimation, but it has several difficulties such as predictions of temperature distribution in a large and closed space that has several compartments, and modeling the heat generating components and the convection-diffusion of heat by ventilation air-conditioning systems. The main purpose of this study was to simulate the temperature distribution and evaluate the average temperature in the CV of a three-loop pressurized water reactor (PWR) during the reactor operation. The simulation considered the heat generation of equipment, flow due to the ventilation and air conditioning systems, heat loss to the CV exterior, and the solar heat. The predicted temperature distribution was significantly affected by the flow. Particularly, openings, which became flow paths, affected the temperature distribution. The temperature increased with a rise in height within the CV and the flow field seemed to transform from forced convection to natural convection. The volume-averaged temperature was different between gas and solid (concrete, CV wall) phases as well as between heights. The total volume-averaged temperature of the CV was nearly equal to the average gas phase temperature. It was found to be easy to evaluate the effect of openings on the temperature distribution and estimate the average temperature in CV by numerical simulation. (author)

  5. Thermal loads on the TJ-II Vacuum Vessel under Neutral Beam Injection

    International Nuclear Information System (INIS)

    Guasp, J.; Fuentes, C.; Liniers, M.

    1996-01-01

    In this study a numerical analysis of power loads on the complex 3D structure of the TJ-II Vacuum Vessel, moderated with reasonable accuracy, under NBI, is done. To do this it has been necessary to modify deeply the DENSB code for power loads in order to include the TJ-II VV wall parts as targets and as beam scrapers, allowing the possibility of self-shadowing. After a short description of the primitive version of the DENSB code (paragraph 2) and of the visualisation code MOVIE(paragraph 3), the DENSB upgrading are described (paragraphs 4,5) and finally the results are presented (paragraph 6). These code modifications and the improving on the visualization tools provide more realistic load evaluations, both with and without plasma, validating former results and showing clearly the VV zones that will need new protections. (Author)

  6. Evaluation of Thermal Load to the Lower Head Vessel Using the ASTEC Computer Code

    International Nuclear Information System (INIS)

    Park, Raejoon; Ahn, Kwangil

    2013-01-01

    The thermal load from the corium to the lower head vessel in the APR (Advanced Power reactor) 1400 during a small break loss of coolant accident (SBLOCA) without a safety injection (SI) has been evaluated using the ASTEC (Accident Source Term Evaluation Code) computer code, which has been developed as a part of the EU (European Union)-SARNET (Severe Accident Research NET work) program. The ASTEC results predict that the reactor vessel did not fail by using an ERVC, in spite of the large melting of the reactor vessel wall in a two-layer formation case of the SBLOCA in the APR1400. The outer surface conditions of the temperature and heat transfer coefficient are not effective on the vessel geometry change, which are preliminary results. A more detailed analysis of the main parameter effects on the corium behavior in the lower plenum is necessary to evaluate the IVR-ERVC in the APR1400, in particular, for a three-layer formation of the TLFW. Comparisons of the present results with others are necessary to verify and apply them to the actual IVR-ERVC evaluation in the APR1400

  7. Analytical investigation of multicavity prestressed concrete pressure vessels for elastic loading conditions

    International Nuclear Information System (INIS)

    Fanning, D.N.

    1978-09-01

    A three-dimensional finite-element analysis of a commercial high-temperature gas-cooled reactor (HTGR) was made using the finite-element code STATIC-SAP. Four loading conditions were analyzed elastically to evaluate the behavior of the concentric core prestressed concrete reactor vessel (PCRV) of the HTGR. The results of the analysis were evaluated in accordance with Section III, Division 2, of the ASME Code for Reactor Vessels and Containments. The calculated maximum stresses were found to be well within the Code-allowable values. The analysis was preceded by an evaluation of candidate computer codes using comparisons of experimental data with analytical results for the Ohbayashi-Gumi multicavity PCRV model. This vessel was chosen as a basis for comparison because of its geometrical similarity to the large multicavity PCRV and the anticipated availability of a complete set of the original experimental data. The three-dimensional finite-element codes NONSAP and STATIC-SAP were used for the analysis of the Ohbayashi-Gumi vessel

  8. 46 CFR 180.204 - Survival craft-vessels operating on coastwise routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft-vessels operating on coastwise routes. 180.204 Section 180.204 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL... Craft § 180.204 Survival craft—vessels operating on coastwise routes. (a) Except as allowed by paragraph...

  9. 46 CFR 117.206 - Survival craft-vessels operating on Great Lakes routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Survival craft-vessels operating on Great Lakes routes... PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Number and Type of Survival Craft § 117.206 Survival craft... vessel certificated to operate on a Great Lakes route must be provided with the survival craft required...

  10. The probabilistic structural integrity assessment of reactor pressure vessels under pressurized thermal shock loading

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mingya, E-mail: chenmingya@cgnpc.com.cn [Suzhou Nuclear Power Research Institute, 215004 Suzhou, Jiangsu Province (China); Lu, Feng; Wang, Rongshan; Yu, Weiwei [Suzhou Nuclear Power Research Institute, 215004 Suzhou, Jiangsu Province (China); Wang, Donghui [State Nuclear Power Plant Service Company, 200237 Shanghai (China); Zhang, Guodong; Xue, Fei [Suzhou Nuclear Power Research Institute, 215004 Suzhou, Jiangsu Province (China)

    2015-12-01

    Highlights: • The methodology and the case study of the FAVOR software were shown. • The over-conservative parameters in the DFM were shown. • The differences between the PFM and the DFM were discussed. • The limits in the current FAVOR were studied. - Abstract: The pressurized thermal shock (PTS) event poses a potentially significant challenge to the structural integrity of the reactor pressure vessel (RPV) during the long time operation (LTO). In the USA, the “screening criteria” for maximum allowable embrittlement of RPV material, which forms part of the USA regulations, is based on the probabilistic fracture mechanics (PFM). The FAVOR software developed by Oak Ridge National Laboratory (ORNL) is used to establish the regulation. As the technical basis of FAVOR is not the most widely-used and codified methodologies, such as the ASME and RCC-M codes, in most countries (with exception of the USA), proving RPV integrity under the PTS load is still based on the deterministic fracture mechanics (DFM). As the maximum nil-ductility-transition temperature (RT{sub NDT}) of the beltline material for the 54 French RPVs after 40 years operation is higher than the critical values in the IAEA-TECDOC-1627 and European NEA/CSNI/R(99)3 reports (while still obviously lower than the “screening criteria” of the USA), it may conclude that the RPV will not be able to run in the LTO based on the DFM. In the FAVOR, the newest developments of fracture mechanics are applied, such as the warm pre-stress (WPS) effect, more accurate estimation of the flaw information and less conservation of the toughness (such as the three-parameter Weibull distribution of the fracture toughness). In this paper, the FAVOR software is first applied to show both the methodology and the results of the PFM, and then the limits in the current FAVOR software (Version 6.1, which represents the baseline for re-assessing the regulation of 10 CFR 50.61), lack of the impact of the constraint effect

  11. Biaxial loading effects on fracture toughness of reactor pressure vessel steel

    International Nuclear Information System (INIS)

    McAfee, W.J.; Bass, B.R.; Bryson, J.W. Jr.; Pennell, W.E.

    1995-03-01

    The preliminary phases of a program to develop and evaluate fracture methodologies for assessing crack-tip constraint effects on fracture toughness of reactor pressure vessel (RPV) steels have been completed by the Heavy-Section Steel Technology (HSST) Program. Objectives were to investigate effect of biaxial loading on fracture toughness, quantify this effect through existing stress-based, dual-parameter, fracture-toughness correlations, or propose and verify alternate correlations. A cruciform beam specimen with 2-D, shallow, through-thickness flaw and a special loading fixture was designed and fabricated. Tests were performed using biaxial loading ratios of 0:1 (uniaxial), 0.6:1, and 1:1 (equi-biaxial). Critical fracture-toughness values were calculated for each test. Biaxial loading of 0.6:1 resulted in a reduction in the lower bound fracture toughness of ∼12% as compared to that from the uniaxial tests. The biaxial loading of 1:1 yielded two subsets of toughness values; one agreed well with the uniaxial data, while one was reduced by ∼43% when compared to the uniaxial data. Results were evaluated using J-Q theory and Dodds-Anderson (D-A) micromechanical scaling model. The D-A model predicted no biaxial effect, while the J-Q method gave inconclusive results. When applied to the 1:1 biaxial data, these constraint methodologies failed to predict the observed reduction in fracture toughness obtained in one experiment. A strain-based constraint methodology that considers the relationship between applied biaxial load, the plastic zone width in the crack plane, and fracture toughness was formulated and applied successfully to the data. Evaluation of this dual-parameter strain-based model led to the conclusion that it has the capability of representing fracture behavior of RPV steels in the transition region, including the effects of out-of-plane loading on fracture toughness. This report is designated as HSST Report No. 150

  12. Variable flaw shape analysis for a reactor vessel under pressurized thermal shock loading

    International Nuclear Information System (INIS)

    Yang, C.Y.; Bamford, W.H.

    1984-01-01

    A study has been conducted to characterize the response of semi-elliptic surface flaws to thermal shock conditions which can result from safety injection actuation in nuclear reactor vessels. A methodology was developed to predict the behavior of a flaw during sample pressurized thermal shock events. The effects of a number of key variables on the flaw propagation were studied, including fracture toughness of the material and its gradient through the thickness, irradiation effects, effects of warm prestressing, and effects of the stainless steel cladding. The results of these studies show that under thermal shock loading conditions the flaw always tends to elongate along the vessel inside surface from the initial aspect ratio. However, the flaw shape always remains finite rather than becoming continuously long, as has often been assumed in earlier analyses. The final shape and size of the flaws were found to be rather strongly dependent on the effects of warm prestressing and the distribution of neutron flux. The improved methodology results in a more accurate and more realistic treatment of flaw shape changes during thermal shock events and provides the potential for quantifying additional margins for reactor vessel integrity analyses

  13. Transient analysis of house load operation for LNPP

    International Nuclear Information System (INIS)

    Shi Junying; Zheng Bin

    2000-01-01

    The author analysis the transient of house load operation for Ling'ao Nuclear Power Plant by using the methods of dynamic simulation and closed loops of primary and secondary system. The transient of house load operation from 100% FP is the most severe that can occur on the unit in normal operation because it causes immediately shedding of 95% of turbine load and requires the unit to operate steadily at reduced power. The results show that the transient can be successful both at beginning of core life and manual house load operation. However, more attentions must be paid to automatic house load operation caused by grid fault at toward end of core life because the success of the transient could be threatened by the actuation of the protection of high flux and high flux rate

  14. Mitigating the Long term Operating Extreme Load through Active Control

    DEFF Research Database (Denmark)

    Koukoura, Christina; Natarajan, Anand

    2014-01-01

    blade azimuth location are shown to affect the extreme blade load magnitude during operation in normal turbulence wind input. The simultaneously controlled operation of generator torque variation and pitch variation at low blade pitch angles is detected to be responsible for very high loads acting...... on the blades. Through gain scheduling of the controller (modifications of the proportional Kp and the integral Ki gains) the extreme loads are mitigated, ensuring minimum instantaneous variations in the power production for operation above rated wind speed. The response of the blade load is examined...

  15. Conceptual Design of Electrical Propulsion System for Nuclear Operated Vessel Adventurer

    International Nuclear Information System (INIS)

    Halimi, B.; Suh, K. Y.

    2009-01-01

    A design concept of the electric propulsion system for the Nuclear Operated Vessel Adventure (NOVA) is presented. NOVA employs Battery Omnibus Reactor Integral System (BORIS), a liquid metal cooled small fast integral reactor, and Modular Optimized Brayton Integral System (MOBIS), a supercritical CO 2 (SCO 2 ) Brayton cycle as power converter to Naval Application Vessel Integral System (NAVIS)

  16. 46 CFR 117.205 - Survival craft-vessels operating on limited coastwise routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Survival craft-vessels operating on limited coastwise... PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Number and Type of Survival Craft § 117.205 Survival craft... the survival craft required by §§ 117.204 (a) through (d) of this part, as applicable. (b) Each vessel...

  17. 46 CFR 117.202 - Survival craft-vessels operating on oceans routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Survival craft-vessels operating on oceans routes. 117... LIFESAVING EQUIPMENT AND ARRANGEMENTS Number and Type of Survival Craft § 117.202 Survival craft—vessels... number of overnight persons allowed, the survival craft requirements contained in paragraph (e) of this...

  18. Transient temperature response of in-vessel components due to pulsed operation in tokamak fusion experimental reactor (FER)

    International Nuclear Information System (INIS)

    Minato, Akio; Tone, Tatsuzo

    1985-12-01

    A transient temperature response of the in-vessel components (first wall, blanket, divertor/limiter and shielding) surrounding plasma in Tokamak Fusion Experimental Reactor (FER) has been analysed. Transient heat load during start up/shut down and pulsed operation cycles causes the transient temperature response in those components. The fatigue lifetime of those components significantly depends upon the resulting cyclic thermal stress. The burn time affects the temperature control in the solid breeder (Li 2 O) and also affects the thermo-mechanical design of the blanket and shielding which are constructed with thick structure. In this report, results of the transient temperature response obtained by the heat transfer and conduction analyses for various pulsed operation scenarios (start up, shut down, burn and dwell times) have been investigated in view of thermo-mechanical design of the in-vessel components. (author)

  19. Part-load pumping operation, control and behaviour

    International Nuclear Information System (INIS)

    1988-01-01

    Twenty one papers are printed. Their main concern is with pump performance under abnormal operating conditions or when operating at part-load. The effect of part-load operation on pump performance, pump internal flow and pump cavitation and noise were considered. The pumps considered are used in a variety of situations and some case studies were discussed. One paper about part-load operation of the boiler pumps for French pressurized water reactors and one paper on pressure pulsations of centrifugal pumps at very low flowrate, are indexed separately. (U.K.)

  20. 77 FR 11995 - Passenger Vessel Operator Financial Responsibility Requirements for Non-Performance of...

    Science.gov (United States)

    2012-02-28

    ... Vessel Operator Financial Responsibility Requirements for Non-Performance of Transportation AGENCY..., 2011, the Commission issued its Notice of Proposed Rulemaking (NPRM) to update its financial... cost of financial responsibility coverage because of the use of alternative coverage options. However...

  1. A generic approach for steel containment vessel success criteria for severe accident loads

    International Nuclear Information System (INIS)

    Sammataro, R.F.; Solonick, W.R.; Edwards, N.W.

    1993-01-01

    Safety has been defined as the foremost design criterion for the Heavy Water New Production Reactor (NPR-HWR) by the U.S. DOE, Office of New Production Reactors (NP). The DOE-NP issued the Deterministic Severe Accident Criteria (DSAC) concept to guide the design of the NPR-HWR containment for resistance to severe accidents. The DSAC concept provides for a generic approach for containment vessel success criteria to predict the threshold of containment failure under severe accident loads. This concept consists of two parts: (1) Problem Statements and (2) Success Criteria. The paper is limited to a discussion of a success criteria. These criteria define acceptable containment response measures and limits for each problem statement. The criteria are based on the 'best estimate' of failure with no conservatism. Rather, conservatism, if required, is to be provided in the problem statements prepared by the designer and/or the regulatory authorities. The success criteria are presented on a multi-tiered basis for static pressure and temperature loadings, dynamic loadings, and missiles that may impact the containment. Within the static pressure and temperature loadings and the dynamic loadings, the criteria are separated into elastic analysis success criteria and inelastic analysis success criteria. Each of these areas, in turn, defines limits on either the stress or strain measures as well as on measures for buckling and displacements. The rationale upon which these criteria are based is contained in referenced documents. Rigorous validation of the criteria by comparison with results from analytical or experimental programs and application of the criteria to a containment design remain as future tasks. (orig./HP)

  2. WRAP TRUPACT loading systems operational test report

    International Nuclear Information System (INIS)

    DOSRAMOS, E.V.

    1999-01-01

    This Operational Test Report documents the operational testing of the TRUPACT process equipment HNF-3918, Revision 0, TRUPACT Operational Test Procedure. The test accomplished the following: Procedure validation; Facility equipment interface; Facility personnel support; and Subcontractor personnel support interface. Field changes are documented as test exceptions with resolutions. All resolutions are completed or a formal method is identified to track the resolution through to completion

  3. The response of pressure vessel steel specimens on drop weight loading

    International Nuclear Information System (INIS)

    Winkler, S.; Kalthoff, J.F.; Gerscha, A.

    1979-01-01

    Load records obtained in instrumented impact tests in general are disturbed by inertia effects. The influence of mechanical damping provisions on these disturbing inertia effects is investigated. Precracked bend specimens are dynamically loaded in a drop weight testing system. The specimens of size 620 mm x 150 mm (25 mm or 50 mm thick) were machined from the pressure vessel steel 22 NiMoCr 37 which was heat treated to achieve a specially hardened condition. The tests were performed at two different low temperatures. The impact velocity was about 4 m/s. As it is usual in instrumented impact testing, the load at the tup of the impining striker is recorded as a function of time during the impact process. In addition the specimen is instrumented by a strain gage close to the crack tip in order to directly measure the stress intensification. Experiments were performed under pure and damped impact conditions. Damping was achieved by utilizing a soft aluminum plate between the striker and the specimen. (orig.)

  4. Loads on reactor pressure vessel internals induced by low-pressure waves

    International Nuclear Information System (INIS)

    Benkert, J.; Mika, C.; Stegemann, D.; Valero, M.

    1978-02-01

    Departing from the conservation theorems for mass and impulse the computer code DRUWE has been developed which allows to calculate loads on the core shell with simplifying assumptions for the first period just after the rupture has opened. It can be supposed that the whole rupture cross section is set free within 15 msec. The calculation progresses in a way that for a core shell the local, timely pressure- and load development, respectively, the total dynamic load as well as the moments acting on the fixing of the core shell, can be calculated. The required input data are merely geometric data on the concept of the pressure vessel and its components as well as the effective subcooling of the fluid. By means of some parameters the programm development can be controlled in a way that the results are available in form of listings or diagrams, respectively, as well as in form of card decks for following investigations, e.g. solidity calculations. (orig./RW) [de

  5. Dynamic simulation of a planar flexible boom for tokamak in-vessel operations

    International Nuclear Information System (INIS)

    Ambrosino, G.; Celentano, G.; Garofalo, F.; Maisonnier, D.

    1991-01-01

    In this paper we present a dynamic model for the analysis of the vibrations of a planar articulated flexible boom to be used for tokamak in-vessel maintenance operations. The peculiarity of the mechanical structure of the boom enables us to consider separately the oscillations in the horizontal and vertical planes so that two separate models can be constructed for describing these phenomena. The results of simulations based on booms like that proposed for NET in-vessel operations are presented. (orig.)

  6. German boiler and pressure vessel codes and standards: materials, manufacture, testing, equipment, erection and operation

    International Nuclear Information System (INIS)

    Steffen, H.P.

    1987-01-01

    The methods by which the safety objectives on the operation of steam boilers and pressure vessels in Germany can be reached are set out in Technical Rules which are compiled and established in technical committees. Typical applications are described in the Technical Rules. A chart shows how the laws, provisions and Technical Rules for the sections 'steam boiler plant' and 'pressure vessels' are interlinked. This chapter concentrates on legal aspects, materials, manufacture, testing, erection and operation of boilers and pressure vessels in Germany. (U.K.)

  7. Effect of fuel assembly mechanical design changes on dynamic response of reactor pressure vessel system under extreme loadings

    International Nuclear Information System (INIS)

    Bhandari, D.R.; Hankinson, M.F.

    1993-01-01

    This paper presents the results of a study to assess the effect of fuel assembly mechanical design changes on the dynamic response of a pressurized water reactor vessel and reactor internals under Loss-Of-Coolant Accident (LOCA) conditions. The results of this study show that the dynamic response of the reactor vessel internals and the core under extreme loadings, such as LOCA, is very sensitive to fuel assembly mechanical design changes. (author)

  8. Thermal Load Analysis of Multilayered Corium in the Lower Head of Reactor Pressure Vessel during Severe Accident

    Energy Technology Data Exchange (ETDEWEB)

    Whang, Seok Won; Park, Hyun Sun [POSTECH, Pohang (Korea, Republic of); Hwang, Tae Suk [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2014-05-15

    In-Vessel Retention (IVR) is one of the severe accident management strategies to terminate or mitigate the severe accident which is also called 'core-melt accident'. The reactor vessel would be cooled by flooding the cavity with water. The molten core mixture is divided into two or three layers due to the density difference. Light metal layer which contains Fe and Zr is on the oxide layer which is consist of UO{sub 2} and ZrO{sub 2}. Heavy metal layer which contains U, Fe and Zr is located under the oxide layer. In oxide layer, the crust which is solidified material is formed along the boundary. The assessment of IVR for nuclear power plant has been conducted with lumped parameter method by Theofanous, Rempe and Esmaili. In this paper, the numerical analysis was performed and verified with the Esmaili's work to analyze thermal load of multilayered corium in pressurized reactor vessel and also to examine the condition of in-vessel corium characteristic before the vessel failure that lead to ex-vessel severe accident progression for example, ex-vessel debris bed cooling. The in-vessel coolability analysis for several scenarios is conducted for the plant which has higher power than AP1000. Two sensitivity analyses are conducted, the first is emissivity of light metal layer and the second is the heat transfer coefficient correlations of oxide layer. The effect of three layered system also investigated. In this paper, the numerical analysis was performed and verified with Esmaili's model to analyze thermal load of multilayered corium in pressurized reactor vessel. For two layered system, thermal load was analyzed according to the severe accident scenarios, emissivity of the light metal layer and heat transfer correlations of the.

  9. Dynamic buckling and nonlinear response of FBR main vessels under earthquake loading

    International Nuclear Information System (INIS)

    Hagiwara, Yutaka; Kawamoto, Yoji; Nakagawa, Masaki; Akiyama, Hiroshi.

    1991-01-01

    Pseudo-dynamic tests of cylindrical shells under high temperature were performed in order to study elasto-plastic shear-bending buckling and the nonlinear response of FBR main vessels under earthquake loading. The test results showed a response reduction effect due to pre-buckling plasticity, and a large seismic margin due to post-buckling energy absorption of the cylinders. A simple expression of the response reduction effect was proposed, as a contribution to the safe and effective seismic design of FBRs. Two methods for seismic margin evaluation were also proposed, and it was shown that appropriate seismic margins can be ensured, when the response reduction effect is incorporated into the seismic design. (author)

  10. Models for ductile crack initiation and tearing resistance under mode 1 loading in pressure vessel steels

    International Nuclear Information System (INIS)

    Jones, M.R.

    1988-06-01

    Micromechanistic models are presented which aim to predict plane strain ductile initiation toughness, tearing resistance and notched bar fracture strains in pressure vessel steels under monotonically increasing tensile (mode 1) loading. The models for initiation toughness and tearing resistance recognize that ductile fracture proceeds by the growth and linkage of voids with the crack-tip. The models are shown to predict the trend of initiation toughness with inclusion spacing/size ratio and can bound the available experimental data. The model for crack growth can reproduce the tearing resistance of a pressure vessel steel up to and just beyond crack growth initiation. The fracture strains of notched bars pulled in tension are shown to correspond to the achievement of a critical volume fraction of voids. This criterion is combined with the true stress - true strain history of a material point ahead of a blunting crack-tip to predict the initiation toughness. An attempt was made to predict the fracture strains of notched tensile bars by adopting a model which predicts the onset of a shear localization phenomenon. Fracture strains of the correct order are computed only if a ''secondary'' void nucleation event at carbide precipitates is taken into account. (author)

  11. 77 FR 62247 - Dynamic Positioning Operations Guidance for Vessels Other Than Mobile Offshore Drilling Units...

    Science.gov (United States)

    2012-10-12

    ... Operations Guidance for Vessels Other Than Mobile Offshore Drilling Units Operating on the U.S. Outer... ``Mobile Offshore Drilling Unit Dynamic Positioning Guidance''. The notice recommended owners and operators of Mobile Offshore Drilling Units (MODUs) follow Marine Technology Society (MTS) Dynamic Positioning...

  12. Mitigating the Long term Operating Extreme Load through Active Control

    International Nuclear Information System (INIS)

    Koukoura, Christina; Natarajan, Anand

    2014-01-01

    The parameters influencing the long term extreme operating design loads are identified through the implementation of a Design of Experiment (DOE) method. A function between the identified critical factors and the ultimate out-of-plane loads on the blade is determined. Variations in the initial blade azimuth location are shown to affect the extreme blade load magnitude during operation in normal turbulence wind input. The simultaneously controlled operation of generator torque variation and pitch variation at low blade pitch angles is detected to be responsible for very high loads acting on the blades. Through gain scheduling of the controller (modifications of the proportional Kp and the integral K gains) the extreme loads are mitigated, ensuring minimum instantaneous variations in the power production for operation above rated wind speed. The response of the blade load is examined for different values of the integral gain as resulting in rotor speed error and the rate of change of rotor speed. Based on the results a new load case for the simulation of extreme loads during normal operation is also presented

  13. Assessment of alternative vessel and blanket design on ITER operation

    Energy Technology Data Exchange (ETDEWEB)

    Cavinato, M., E-mail: mario.cavinato@f4e.europa.e [FUSION FOR ENERGY Joint Undertaking, 08019 Barcelona (Spain); Portone, A.; Saibene, G.; Sartori, R. [FUSION FOR ENERGY Joint Undertaking, 08019 Barcelona (Spain); Albanese, R.; Ambrosino, G.; Ariola, M. [Associazione Euratom-ENEA-CREATE, DIMET, Universita degli Studi di Napoli (Italy); Artaserse, G. [Associazione Euratom-ENEA-CREATE, DIMET, Universita degli Studi di Reggio Calabria (Italy); Mattei, M. [Associazione Euratom-ENEA-CREATE, DIAM, Seconda Universita di Napoli, Via Roma 29, Aversa, CE 81031 Italy (Italy); Pironti, A. [Associazione Euratom-ENEA-CREATE, DIMET, Universita degli Studi di Napoli (Italy); Villone, F. [Associazione Euratom-ENEA-CREATE, DIMET, Universita degli Studi di Cassino (Italy)

    2010-12-15

    In the framework of the ITER project, an investigation has been conducted on an alternative vessel and blanket design, aimed at reducing cost and production risk. The modifications proposed have a strong impact on plasma control since they affect the main conducting structures surrounding the plasma column, providing passive stabilization but at the same time shielding the field generated by the active coils to control the plasma motion and shape. An extensive analysis was performed to assess the plasma vertical controllability and the modified requirements to the in-vessel vertical stability coils system as well as to the external Poloidal Field coils system. A similar analysis was aimed at assessing the performance of the shape control system in presence of the modified structures. The effect on plasma breakdown was also evaluated in terms of maximum initial loop voltage, quality of magnetic null and the flux loss related to the breakdown delay that was quantified under the same hypothesis employed by ITER for the baseline design. Furthermore, the modified design presents issues for the magnetic diagnostic system, related to the shielding of the probes by the eddy currents, which were analysed with a 3D model. The results of the analyses performed have some general interest in particular regarding the influence on plasma stability of 3D structures with close proximity to the plasma. The present paper aims at giving an overview of the analyses that have been carried out and a summary of the results in terms of impact of the modified design on plasma control and scenario, and in general an evaluation of the role of passive structure in plasma vertical stability and shape control.

  14. Human factors in operational maintenance on future naval vessels

    NARCIS (Netherlands)

    Post, W.M.; Schreurs, J.C.; Rakhorst-Oudendijk, M.L.W.; Badon Ghijben, N.A.; Diggelen, J. van

    2014-01-01

    The increasing complexity of operational maintenance on naval platforms and the need to sustain this also in battle conditions are in conflict with the requirement for crew reduction. This asks for a new approach. The Netherlands MoD knows how to develop technical solutions for operational

  15. Remotely operated top loading filter housing

    International Nuclear Information System (INIS)

    Ross, M.J.; Carter, J.A.

    1989-01-01

    A high-efficiency particulate air (HEPA) filter system was developed for the Fuel Processing Facility at the Idaho Chemical Processing Plant. The system utilizes commercially available HEPA filters and allows in-cell filters to be maintained using operator-controlled remote handling equipment. The remote handling tasks include transport of filters before and after replacement, removal and replacement of the filter from the housing, and filter containment

  16. Vessel Segmentation in Retinal Images Using Multi-scale Line Operator and K-Means Clustering.

    Science.gov (United States)

    Saffarzadeh, Vahid Mohammadi; Osareh, Alireza; Shadgar, Bita

    2014-04-01

    Detecting blood vessels is a vital task in retinal image analysis. The task is more challenging with the presence of bright and dark lesions in retinal images. Here, a method is proposed to detect vessels in both normal and abnormal retinal fundus images based on their linear features. First, the negative impact of bright lesions is reduced by using K-means segmentation in a perceptive space. Then, a multi-scale line operator is utilized to detect vessels while ignoring some of the dark lesions, which have intensity structures different from the line-shaped vessels in the retina. The proposed algorithm is tested on two publicly available STARE and DRIVE databases. The performance of the method is measured by calculating the area under the receiver operating characteristic curve and the segmentation accuracy. The proposed method achieves 0.9483 and 0.9387 localization accuracy against STARE and DRIVE respectively.

  17. Estimation of inelastic behavior for a tapered nozzle in vessel due to thermal transient load using stress redistribution locus method

    International Nuclear Information System (INIS)

    Kobayashi, Ken-ichi; Yamada, Jun-ichi

    2010-01-01

    Simplified inelastic design procedures for elevated temperature components have been required to reduce simulation cost and to shorten a period of time for developing new projects. Stress redistribution locus (SRL) method has been proposed to provide a reasonable estimate employing both the elastic FEM analysis and a unique hyperbolic curve: ε tilde={1/σ tilde + (κ - 1)σ tilde}/κ, where ε tilde and σ tilde show dimensionless strain and stress normalized by corresponding elastic ones, respectively. This method is based on a fact that stress distribution in well deformed or high temperature components would change with deformation or time, and that the relation between the dimensionless stress and strain traces a kind of the elastic follow-up locus in spite of the constitutive equation of material and loading modes. In this paper, FEM analyses incorporating plasticity and creep in were performed for a tapered nozzle in reactor vessel under some thermal transient loads through the nozzle thickness. The normalized stress and strain was compared with the proposed SRL curve. Calculation results revealed that a critical point in the tapered nozzle due to the thermal transient load depended on a descending rate of temperature from the higher temperature in the operation cycle. Since the inelastic behavior in the nozzle resulted in a restricted area, the relationship between the normalized stress and strain was depicted inside the proposed SRL curve: Coefficient κ of the SRL in analyses is greater than the proposed one, and the present criterion guarantees robust structures for complicated components involving inelastic deformation. (author)

  18. Stress concentration factors for integral and pad reinforced nozzles in spherical pressure vessels subjected to radial load and moment

    International Nuclear Information System (INIS)

    Soliman, S.F.; Gill, S.S.

    1979-01-01

    Charts are presented giving the elastic stress concentration factors in spherical pressure vessels with pad and integral reinforcement for radial branches subjected to radial load and moment. The effect of all the geometrical parameters is discussed, including the limitations of thin shell theory on the validity of the results. (author)

  19. [Key vessels assessment and operation highlights in laparoscopic extended right hemicolectomy].

    Science.gov (United States)

    Wang, Hao; Zhao, Quanquan

    2018-03-25

    Laparoscopic radical colectomies have been more widely used gradually, among which laparoscopic extended right hemicolectomy is considered as the most difficult procedure. The difficulty of extended right hemicolectomy lies in the need to dissect lymph nodes along the superior mesenteric vein (SMV) and disconnect numerous and possible aberrant vessels. To address this problem, we emphasize two points in key vessel assessment: getting familiar with the anatomy along the medial-to-lateral approach and having a good understanding about the preoperative imaging presentations. An accurately preoperative imaging assessment by abdominal enhanced CT can help the surgeon understand the relative position of the key vessels to be dealt with during operation and the situation of the possible aberrant vessels so as to guide the procedure more effectively and facilitate the prevention and management of the intraoperative complications. During operation, the operator should pay special attention to the management of the vessels in the ileocolic vessel region, Henle's trunk and middle colon vessels. The operation highlights of the key vessels are as follows: (1) The ileocolic vessels: identifying the Toldt's gap correctly and opening the vascular sheath of the SMV securely; making sure that the duodenum is well protected. (2) Henle's trunk: dissecting along the surface of the Henle's trunk; preserving the anterior superior pancreaticoduodenal vein (ASPDV) and main trunk of the Henle's trunk; disconnecting the roots of the right colic vein (RCV) and right gastroepiploic vein (RGEV), and then dissecting lymph nodes along the surface of the pancreas. (3) The middle colon vessels: identifying the root of the middle colon vessel along the lower edge of the pancreas; avoiding entering behind the pancreas; mobilizing the transverse mesocolon sufficiently along the surface of the pancreas. Finally, we discuss and analyze the disputes currently existing in laparoscopic extended right

  20. Effects of dynamic loading of motor-operated valve actuators

    International Nuclear Information System (INIS)

    Damerell, P.S.; Daubresse, S.; Wolfe, K.J.; Dogan, T.; Gleeson, J.

    1994-01-01

    Experience has shown that valves with rising, nonrotating stems that are operated using electro-motor driven actuators can be susceptible to changes in output thrust at a constant torque switch setting as a result of changes in stem load time history. This effect is a concern because tests on these types of valves to verify thrust achieved at torque switch trip are often performed in situ under load conditions different from the required performance conditions. As part of a motor-operated valve research program being carried out by the Electric Power Research Institute, tests of typical electric motor actuators used with nuclear services valves have been performed. The test results show that changes in output thrust with load time history occur o varying degrees on different stem and stem nut combinations. When the effect exists, there is generally an increase in thrust at torque switch trip when load is developed rapidly from low initial loads, compared to when load is developed slowly. The effect is mainly a result of changes in the coefficient of friction at the stem-stem nut interface. The coefficient of friction is temporarily reduced under rapid loading conditions from low initial load, leading to increased thrust. The root cause is hypothesized to be a open-quotes squeeze-filmclose quotes effect, whereby mixed-mode lubrication (hydrodynamic plus boundary) temporarily replaces boundary lubrication. This paper describes the results of tests performed to better understand the phenomenon

  1. Transient pressure measurements at part load operating condition of ...

    Indian Academy of Sciences (India)

    Rahul Goyal

    2 Water Power Laboratory, Department of Energy and Process Engineering, Norwegian ... The present paper focuses on the investigation of a high head model Francis turbine operating at 50% load. ..... cascade of bandpass filters in MATLAB to eliminate the .... simulation of unsteady operation of hydroelectric systems.

  2. 49 CFR 176.78 - Use of power-operated industrial trucks on board vessels.

    Science.gov (United States)

    2010-10-01

    ... operation may expose the operator to danger from a falling object, the truck must be equipped with a driver... used to handle small objects or unstable loads must be equipped with a load backrest extension having... must be permanently connected to an exhaust duct leading to the open deck and terminate in a gooseneck...

  3. An improved control system for a remotely operated vessel

    Science.gov (United States)

    Bachnak, Rafic; Mendez, Marc; Esparza, Jack; Fahed, Oliver

    2006-05-01

    Collecting environmental data in coastal bays presents several challenges to the scientist. One of the most pressing issues is how to efficiently and reliably gather data in shallow water areas-environments that often preclude the use of traditional boats. Obstacles that are encountered in such environments include difficulty in covering large territories and the presence of inaccessible areas due to a variety of reasons, such as soft bottoms or contamination. There is also a high probability of disturbing the test area while placing the sensors. This paper outlines the development of a remotely operated boat and its real-time control system.

  4. Scenario based optimization of a container vessel with respect to its projected operating conditions

    Directory of Open Access Journals (Sweden)

    Jonas Wagner

    2014-06-01

    Full Text Available In this paper the scenario based optimization of the bulbous bow of the KRISO Container Ship (KCS is presented. The optimization of the parametrically modeled vessel is based on a statistically developed operational profile generated from noon-to-noon reports of a comparable 3600 TEU container vessel and specific development functions representing the growth of global economy during the vessels service time. In order to consider uncertainties, statistical fluctuations are added. An analysis of these data lead to a number of most probable upcoming operating conditions (OC the vessel will stay in the future. According to their respective likeliness an objective function for the evaluation of the optimal design variant of the vessel is derived and implemented within the parametrical optimization workbench FRIENDSHIP Framework. In the following this evaluation is done with respect to vessel's calculated effective power based on the usage of potential flow code. The evaluation shows, that the usage of scenarios within the optimization process has a strong influence on the hull form.

  5. Scenario based optimization of a container vessel with respect to its projected operating conditions

    Science.gov (United States)

    Wagner, Jonas; Binkowski, Eva; Bronsart, Robert

    2014-06-01

    In this paper the scenario based optimization of the bulbous bow of the KRISO Container Ship (KCS) is presented. The optimization of the parametrically modeled vessel is based on a statistically developed operational profile generated from noon-to-noon reports of a comparable 3600 TEU container vessel and specific development functions representing the growth of global economy during the vessels service time. In order to consider uncertainties, statistical fluctuations are added. An analysis of these data lead to a number of most probable upcoming operating conditions (OC) the vessel will stay in the future. According to their respective likeliness an objective function for the evaluation of the optimal design variant of the vessel is derived and implemented within the parametrical optimization workbench FRIENDSHIP Framework. In the following this evaluation is done with respect to vessel's calculated effective power based on the usage of potential flow code. The evaluation shows, that the usage of scenarios within the optimization process has a strong influence on the hull form.

  6. Mass transfer experiments for the heat load during in-vessel retention of core melt

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae Kyun; Chung, Bum Jin [Dept. of Nuclear Engineering, Kyung Hee University, Seoul (Korea, Republic of)

    2016-08-15

    We investigated the heat load imposed on the lower head of a reactor vessel by the natural convection of the oxide pool in a severe accident. Mass transfer experiments using a CuSO{sub 4}–H{sub 2}SO{sub 4} electroplating system were performed based on the analogy between heat and mass transfer. The Ra′{sub H} of 10{sup 14} order was achieved with a facility height of only 0.1 m. Three different volumetric heat sources were compared; two had identical configurations to those previously reported, and the other was designed by the authors. The measured Nu's of the lower head were about 30% lower than those previously reported. The measured angular heat flux ratios were similar to those reported in existing studies except for the peaks appearing near the top. The volumetric heat sources did not affect the Nu of the lower head but affected the Nu of the top plate by obstructing the rising flow from the bottom.

  7. On the prediction of the reactor vessel integrity under severe accident loadings (RPVSA)

    Energy Technology Data Exchange (ETDEWEB)

    Krieg, R. E-mail: maeule@irs.fzk.de; Devos, J.; Caroli, C.; Solomos, G.; Ennis, P.J.; Kalkhof, D

    2001-11-01

    In order to allow more reliable predictions on the lower head response under core melt-down conditions, the temperature distribution has been analysed including the natural convection in the corium pool. Furthermore, the mechanical models and the failure criteria have been improved based on the RUPTHER and FASTHER experiments where typical temperature gradients are simulated. Lower head local melting as well as corium crust development has been addressed in the CORVIS experiments studying the contact between an alumina/iron thermite and a thick steel plate. The upper head loading by corium impact due to a postulated in-vessel steam explosion has been investigated by the BERDA experiments. Similarity rules were considered such that the results can be directly converted to reactor conditions. Based on these investigations admissible steam explosion energy releases are determined which the upper head can carry. If these limits are not exceeded the reactor containment cannot be endangered by broken head fragments. To provide the necessary basic data, mechanical material tests have been performed.

  8. A locking mechanism for securing a loading buoy to a vessel. Lsemekanisme for fastgjring av en lastebye til et farty

    Energy Technology Data Exchange (ETDEWEB)

    Breivik, K.; Smedal, A.

    1994-07-04

    The invention relates to a locking mechanism for securing a loading/unloading buoy on a vessel. The buoy is of the type to be introduced into a submerged downwardly open receiving space in the vessel, and to be fastened in a releasable manner in the receiving space. The mechanism comprises hydraulically actuated locking elements, mounted about horizontal axes at the sides of the receiving space, to pivot between the locking and releasing positions, the buoy having a peripheral collar having a downwards facing abutment edge for engagement with the locking elements in the locking position thereof. 6 figs.

  9. Behavior of an operating floor subjected to heavy load drops

    International Nuclear Information System (INIS)

    Levin, H.A.; Chugh, S.C.; Goodyear, W.D.; Hall, W.J.; Tracy, T.J.

    1984-01-01

    A structural evaluation of the behavior of a Boiling Water Reactor operating floor subjected to postulated heavy load impact is presented relative to the evaluation of nuclear industry requirements for addressing the safe handling of heavy loads. A methodology for evaluation of important modes of structural response is presented along with a specification of performance limits that are consistent with desired functional requirements of the operating floor system. Options for improving undesirable behavior are discussed based upon an understanding of the physical phenomena involved, ultimately factoring this into a modification program. Reference is made to recent test experience that is applicable to the improvement of structural performance in modes of high shear ductility. Other relevant information is referenced that is applicable to the overall structural evaluation of nuclear power plant heavy load handling operations

  10. Nuclear reactor pressure vessel integrity insurance by crack arrestability evaluation using load from CVN tests

    International Nuclear Information System (INIS)

    Fabry, A.

    1997-01-01

    The present work is undertaken in the framework of nuclear reactor pressure vessel (RPV) surveillance and aims at revisiting the crack arrest approach to structural integrity insurance. This approach, performed under normal plant operation conditions, can also offer an attractive alternative to the crack initiation philosophy promoted for accidental analysis. To this end, an accidental conservative, cost effective and robust methodology is forwarded and demonstrated: it makes use of the crack arrest information contained in the instrumented Charpy V-notch impact test and/or in the shear fracture appearance of broken samples. Particular attention is paid to the appraisal of uncertainties and the related safety margin. The resulting capability is placed in perspective with the state-of-the-art crack initiation methodology based on the slow bend testing of recracked specimens, presently under standardization world-wide. The investigation leads to highlight three conceptual weaknesses of current enfgineering and regulatory practices. Improved crack arrestability evaluation emerges as an optimal approach to insure safe PWR operation up to design end-of-life and beyond

  11. Nuclear reactor pressure vessel integrity insurance by crack arrestability evaluation using load from CVN tests

    Energy Technology Data Exchange (ETDEWEB)

    Fabry, A.

    1997-10-15

    The present work is undertaken in the framework of nuclear reactor pressure vessel (RPV) surveillance and aims at revisiting the crack arrest approach to structural integrity insurance. This approach, performed under normal plant operation conditions, can also offer an attractive alternative to the crack initiation philosophy promoted for accidental analysis. To this end, an accidental conservative, cost effective and robust methodology is forwarded and demonstrated: it makes use of the crack arrest information contained in the instrumented Charpy V-notch impact test and/or in the shear fracture appearance of broken samples. Particular attention is paid to the appraisal of uncertainties and the related safety margin. The resulting capability is placed in perspective with the state-of-the-art crack initiation methodology based on the slow bend testing of recracked specimens, presently under standardization world-wide. The investigation leads to highlight three conceptual weaknesses of current enfgineering and regulatory practices. Improved crack arrestability evaluation emerges as an optimal approach to insure safe PWR operation up to design end-of-life and beyond.

  12. Stresses from pressure, radial, and moment loads in cylinder-to-cylinder vessel by a finite plate method

    International Nuclear Information System (INIS)

    Brown, S.J.; Fox, M.E.

    1977-08-01

    A structural problem that has received continued interest and development over the last several decades is the determination of stresses in two normally intersecting cylindrical shells subjected to internal pressure and external loading. In nuclear pressure vessels the external loading of the vessel through the attachment is encountered in thermal interaction, seismic loading and various postulated rupture or failure mechanisms. A simple technique, the Finite Plate Method, (FPM) is presented to analyze stresses in cylinder-to-cylinder junctures. The approach uses shallow shell formulations and a three term series expansion plate formulation, which limits the range of applicability. It is felt that the value of the method is its accuracy, economy, and ease in modeling a structure which falls within the range of applicability. Another appealing feature of the method is that its simplistic approach of superposition of results permits an easy extension to include additional loads not treated. For those mechanical loadings not developed, it is felt that their effect can either be accounted for by the mechanisms discussed or by simple calculations. Generally, the stresses resulting from torsional or transverse shear are small compared to the loads discussed, however, these shear effects may be included. Finally, in the instance of thermal stress within the cylinder-to-cylinder structure, it has been shown in an unpublished study by Brown that the FPM yields very good results for the range of curvatures discussed

  13. Scenario based optimization of a container vessel with respect to its projected operating conditions

    Directory of Open Access Journals (Sweden)

    Wagner Jonas

    2014-06-01

    Full Text Available In this paper the scenario based optimization of the bulbous bow of the KRISO Container Ship (KCS is presented. The optimization of the parametrically modeled vessel is based on a statistically developed operational profile generated from noon-to-noon reports of a comparable 3600 TEU container vessel and specific development functions representing the growth of global economy during the vessels service time. In order to consider uncertainties, statistical fluctuations are added. An analysis of these data lead to a number of most probable upcoming operating conditions (OC the vessel will stay in the future. According to their respective likeliness an objective function for the evaluation of the optimal design variant of the vessel is derived and implemented within the parametrical optimization workbench FRIENDSHIP Framework. In the following this evaluation is done with respect to vessel’s calculated effective power based on the usage of potential flow code. The evaluation shows, that the usage of scenarios within the optimization process has a strong influence on the hull form.

  14. 46 CFR 520.11 - Non-vessel-operating common carriers.

    Science.gov (United States)

    2010-10-01

    ... CARRIER AUTOMATED TARIFFS § 520.11 Non-vessel-operating common carriers. (a) Financial responsibility. An... its tariff publication: (1) That it has furnished the Commission proof of its financial responsibility..., insurance policy, or guaranty; (5) The number of the bond, insurance policy or guaranty; and (6) Where...

  15. 46 CFR 117.204 - Survival craft-vessels operating on coastwise routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Survival craft-vessels operating on coastwise routes... PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Number and Type of Survival Craft § 117.204 Survival craft... allowed, the following survival craft requirements apply when not engaged in an overnight voyage: (1...

  16. Replacement of a vessel head, an operation which today gets easily into its stride

    International Nuclear Information System (INIS)

    Mardon, P.; Chaumont, J.C.; Lambiotte, P.

    1995-01-01

    In 1992, one year after the detection of a leak in a vessel head of the Electricite de France (EDF) Bugey 4 reactor, the head was replaced by the Framatome-Jeumont Industrie Group. Today, this group, which has developed new methods and new tools to optimize the cost, the time-delay and the dosimetry of this kind of intervention, has performed 11 additional replacements, two of which on 1300 MWe power units. This paper describes step by step the successive operations required for a complete vessel head replacement, including the testing of safety systems before starting up the reactor. (J.S.). 7 photos

  17. Aging impact on the safety and operability of nuclear reactor pressure vessels

    International Nuclear Information System (INIS)

    Pennell, W.E.

    1992-01-01

    Irradiation embrittlement causes a loss of reactor vessel material fracture toughness as nuclear plants age. Fracture mechanics based regulatory requirements limit the permissible level of irradiation embrittlement such that essential fracture prevention margins are maintained throughout the plant operating life. This paper reviews the regulatory requirements and the underlying fracture mechanics technology. Issues identified with that technology are identified and research programs implemented to resolve the issues are described. Where possible, an assessment is given of the anticipated impact on the research program output will have on the reactor vessel fracture-margin assessment process

  18. Verification and application of MASTER for load follow operation

    International Nuclear Information System (INIS)

    Park, Yong Soo; Cho, Byung Oh; Lee, Chang Ho; Jung, Yil Sup; Park, Chan Oh

    1996-01-01

    The xenon dynamics module in the nuclear design code MASTER was verified through a simulation calculation. The simulation result shows that the xenon dynamics module in MASTER can trace and predict xenon behavior with accuracy under any core transient state and therefore can simulate load follow operations

  19. Dynamic analysis of crack growth and arrest in a pressure vessel subjected to thermal and pressure loading

    International Nuclear Information System (INIS)

    Brickstad, B.

    1984-01-01

    Predictions of crack arrest behaviour are performed for a cracked reactor pressure vessel under both thermal and pressure loading. The object is to compare static and dynamic calculations. The dynamic calculations are made using an explicit finite element technique where crack growth is simulated by gradual nodal release. Three different load cases and the effect of different velocity dependence on the crack propagation toughness are studied. It is found that for the analysed cases the static analysis is slightly conservative, thus justifying its use for these problems. (orig.)

  20. Dynamic analysis of scraper conveyor operation with external loads

    Directory of Open Access Journals (Sweden)

    Świder Jerzy

    2017-01-01

    Full Text Available A load to an armoured face conveyor (AFC during coal mining is changeable and very difficult or even impossible to be predicted. Changes of the load to the upper scraper chain affect the load of the driving motor and generate changes in a scraper chain tension. Impact of increasing the external load to the upper scraper chain on the operation of electric motors and on the scraper chain tension is presented. The developed numerical model of the Rybnik 850 conveyor enabled identifying the places of the scraper chain high tension or places of its loosening. An impact of changing frequency of driving motor voltage on AFC’s operational conditions was tested and analysed using the AFC’s numerical model. During tests, tension of the scraper chain on the discharge end and the return end was recorded. High tension of the scraper chain and its loosening during the changeable load were also recorded on upward and downward transportation of run-of-mine material.

  1. Motor operated valve testing and the 'rate of loading' phenomenon

    International Nuclear Information System (INIS)

    Black, B.R.

    1991-01-01

    This paper discusses valve design features which affect the ability to predict motor operated valve (MOV) performance and reviews factors which should be considered when selecting switch settings to limit stem loads. Considerable attention is given to the rate of loading phenomenon which affects the relationship between valve stem thrust and actuator spring pack deflection. Equations are developed, and testing is discussed which permit the construction of an MOV dynamic model. Factors which must be considered when maintaining switch settings correct throughout the life of the plant are discussed. And switch setting acceptance criteria for use with baseline Static and Design Basis testing are suggested

  2. 50 CFR 216.46 - U.S. citizens on foreign flag vessels operating under the International Dolphin Conservation...

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false U.S. citizens on foreign flag vessels operating under the International Dolphin Conservation Program. 216.46 Section 216.46 Wildlife and Fisheries....46 U.S. citizens on foreign flag vessels operating under the International Dolphin Conservation...

  3. Study on fatigue analysis for operational load histories

    International Nuclear Information System (INIS)

    Wilhelm, Paul; Rudolph, Juergen; Steinmann, Paul

    2013-01-01

    Some laboratories performed fatigue tests in dissolved oxygen water at elevated temperature to better understand the influence of a long hold-time within cyclic loading. Also, the combined effect of complex waveform and surface finish was examined. The data show a less severe influence compared to the prediction model from Argonne National Laboratory; an increase in fatigue life was noticed and attributed to different effects. To evaluate an operational load history with this experimental data an algorithm is developed, which finds hold-times and the examined complex waveform in a stress-time series. All those cycles, which are either geometrically comparable to the complex loading signal or containing a hold period, are evaluated with the test results and not with the formula from Argonne National Laboratory. The reduction of the cumulative usage factor is calculated. Based on this discussion a realistic test condition is derived for further research activities.

  4. Rapid Operational Access and Maneuver Support (ROAMS) Platform for Improved Military Logistics Lines of Communication and Operational Vessel Routing

    Science.gov (United States)

    2017-06-01

    discussed in detail. Toolbox: AdH. AdH is a finite element engine capable of solving the 2D and three-dimensional (3D) shallow water equations, the...sites will be the shortest that exists on the mesh. However, the algorithm neither guarantees that the found path will satisfy all navigation...between resolution and computation time. Penalty Function: Draft. The draft constraint ensures that the vessel operates only in sufficiently deep

  5. Combining operational models and data into a dynamic vessel risk assessment tool for coastal regions

    Science.gov (United States)

    Fernandes, R.; Braunschweig, F.; Lourenço, F.; Neves, R.

    2016-02-01

    The technological evolution in terms of computational capacity, data acquisition systems, numerical modelling and operational oceanography is supplying opportunities for designing and building holistic approaches and complex tools for newer and more efficient management (planning, prevention and response) of coastal water pollution risk events. A combined methodology to dynamically estimate time and space variable individual vessel accident risk levels and shoreline contamination risk from ships has been developed, integrating numerical metocean forecasts and oil spill simulations with vessel tracking automatic identification systems (AIS). The risk rating combines the likelihood of an oil spill occurring from a vessel navigating in a study area - the Portuguese continental shelf - with the assessed consequences to the shoreline. The spill likelihood is based on dynamic marine weather conditions and statistical information from previous accidents. The shoreline consequences reflect the virtual spilled oil amount reaching shoreline and its environmental and socio-economic vulnerabilities. The oil reaching shoreline is quantified with an oil spill fate and behaviour model running multiple virtual spills from vessels along time, or as an alternative, a correction factor based on vessel distance from coast. Shoreline risks can be computed in real time or from previously obtained data. Results show the ability of the proposed methodology to estimate the risk properly sensitive to dynamic metocean conditions and to oil transport behaviour. The integration of meteo-oceanic + oil spill models with coastal vulnerability and AIS data in the quantification of risk enhances the maritime situational awareness and the decision support model, providing a more realistic approach in the assessment of shoreline impacts. The risk assessment from historical data can help finding typical risk patterns ("hot spots") or developing sensitivity analysis to specific conditions, whereas real

  6. Applying the TOC Project Management to Operation and Maintenance Scheduling of a Research Vessel

    Science.gov (United States)

    Manti, M. Firdausi; Fujimoto, Hideo; Chen, Lian-Yi

    Marine research vessels and their systems are major assets in the marine resources development. Since the running costs for the ship are very high, it is necessary to reduce the total cost by an efficient scheduling for operation and maintenance. To reduce project period and make it efficient, we applied TOC project management method that is a project management approach developed by Dr. Eli Goldratt. It challenges traditional approaches to project management. It will become the most important improvement in the project management since the development of PERT and critical path methodologies. As a case study, we presented the marine geology research project for the purpose of operations in addition to repair on the repairing dock projects for maintenance of vessels.

  7. Engineering to Control Noise, Loading, and Optimal Operating Points

    International Nuclear Information System (INIS)

    Mitchell R. Swartz

    2000-01-01

    Successful engineering of low-energy nuclear systems requires control of noise, loading, and optimum operating point (OOP) manifolds. The latter result from the biphasic system response of low-energy nuclear reaction (LENR)/cold fusion systems, and their ash production rate, to input electrical power. Knowledge of the optimal operating point manifold can improve the reproducibility and efficacy of these systems in several ways. Improved control of noise, loading, and peak production rates is available through the study, and use, of OOP manifolds. Engineering of systems toward the OOP-manifold drive-point peak may, with inclusion of geometric factors, permit more accurate uniform determinations of the calibrated activity of these materials/systems

  8. LOGISTIC SYSTEM OF LOAD DELIVERY AND QUALITY OF ITS OPERATION

    Directory of Open Access Journals (Sweden)

    O. G. Drozdovskaya

    2006-01-01

    Full Text Available The paper considers an opportunity for obtaining a competitive advantage by a transport and dispatch service company in the market of transport services while establishing a logistic system of load delivery. A model of delivery system, an universal scheme of system designing for every specific case are presented and also indices for evaluation of its operational quality are proposed in the paper.

  9. Intraoperative angiography in reconstructive vessel operations in the lower parts of the body

    International Nuclear Information System (INIS)

    Zehle, A.; Weinhold, C.H.; Hauger, W.

    1981-01-01

    The intraoperative angiography offers decisive advantages in reconstructive vessel operations, because this technique permits a direct and immediate examination of the obtained results and which thus can directly influence the technical and tactic management. Therefore this method allows in the most favourable case to improve prognosis. The technical realization and the procedure are facilitated by the combination of screening method and simple documentation, which is presented here. (orig./MG) [de

  10. Preliminary assessment of the effects of biaxial loading on reactor pressure vessel structural-integrity-assessment technology

    International Nuclear Information System (INIS)

    Pennell, W.E.; Bass, B.R.; Bryson, J.W.; Dickson, T.L.; McAfee, W.J.; Merkle, J.G.

    1996-01-01

    Effects of biaxial loading on shallow-flaw fracture toughness were studied to determine potential impact on structural integrity assessment of a reactor pressure vessel (RPV) under pressurized thermal shock (PTS) transient loading and pressure-temperature (PT) loading produced by reactor heatup and cooldown transients. Biaxial shallow-flaw fracture-toughness tests results were also used to determine the parameter controlling fracture in the transition temperature range, and to develop a related dual-parameter fracture-toughness correlation. Shallow-flaw and biaxial loading effects were found to reduce the conditional probability of crack initiation by a factor of nine when the shallow-flaw fracture-toughness K Jc data set, with biaxial-loading effects adjustments, was substituted in place of ASME Code K Ic data set in PTS analyses. Biaxial loading was found to reduce the shallow-flaw fracture toughness of RPV steel such that the lower-bound curve was located between ASME K Ic and K IR curves. This is relevant to future development of P-T curve analysis procedures. Fracture in shallow-flaw biaxial samples tested in the lower transition temperature range was shown to be strain controlled. A strain-based dual-parameter fracture-toughness correlation was developed and shown to be capable of predicting the effect of crack-tip constraint on fracture toughness for strain-controlled fracture

  11. After-operating properties of nuclear reactor vessel materials of Lenin atomic ice breaker and prospective of reactor vessels radiation life prolongation

    International Nuclear Information System (INIS)

    Platonov, P.A.; Shtrombakh, Ya.I.; Amaev, A.D.; Krasikov, E.A.; Korolev, Yu.N.; Zabusov, O.O.; Glushakov, G.M.

    2001-01-01

    A post-operational state of the icebreaker Lenin reactor vessel metal is investigated. It is shown that a base metal of the icebreaker Lenin reactor vessel is of high quality as by an initial value of critical temperature of embrittlement, so by its radiation resistance. The weld metal possesses a sufficient radiation resistance but has an insufficient initial ductile-brittle transition temperature (approximately 63 Deg C). It is necessary to note that the final stage of operation for nuclear steam-generating plant should be carried out at the coolant temperature as high as possible [ru

  12. Design, fabrication and operating experience of Monju ex-vessel fuel storage tank

    International Nuclear Information System (INIS)

    Yokota, Yoshio; Yamagishi, Yoshiaki; Kuroha, Mitsuo; Inoue, Tatsuya

    1995-01-01

    In FBRs there are two methods of storing and cooling the spent fuel - the in-vessel storage and the ex-vessel storage. Because of the sodium leaks through the tank at the beginning of pre-operation, the utilization of the ex-vessel fuel storage tank (EVST) of some FBR plant has been changed from the ex-vessel fuel storage to the interim fuel transfer tank. This led to reactor designers focusing on the material, structure and fabrication of the carbon steel sodium storage tanks worldwide. The Monju EVST was at the final stage of the design, when the leaks occurred. The lesson learned from that experience and the domestic fabrication technology are reflected to the design and fabrication of the Monju EVST. This paper describes the design, fabrication and R and D results for the tank, and operating experience in functional test. The items to be examined are as follows: (1) Overall structure of the tank and design philosophy on the function, (2) Structure of the cover shielding plug and its design philosophy, (3) Structures of the rotating rack and its bearings, and their design philosophy, (4) Cooling method and its design philosophy, (5) Structure and fabrication of the cooling coil support inside EVST with comparison of leaked case, (6) R and D effort for items above. The fabrication of the Monju EVST started in August 1986 and it was shipped to the site in March 1990. Installation was completed in November 1990, and sodium fill after pre-heating started in 1991. The operation has been continued since September 1992. In 1996 when the first spent fuel is stored, its total functions will be examined. (author)

  13. Features of systems for operational control of WWER vessel metal, used in the USSR

    International Nuclear Information System (INIS)

    Yurchenko, Yu.F.

    1987-01-01

    The report descrides key features of an improved system developed to serve for monitoring the soundness of the metal material of the operating high-pressure reactor vessels in nuclear power generation plants in the Soviet Union. The most important feature is that an external monitoring subsystem is incorporated in the system. The subsystem has the advantage of ensuring the following: high defect detectability due to the absense of austenite lining on the outer surface of the reactor vessel; implementation of monitoring work without removing in-pile structures in parallel with preventive maintenance work during annual partial fuel replacement; and application of other monitoring techniques, such as accoustic emission, in future. Another feature is that radiography by iridium-192 and cobalt-90 is employed to support the external monitoring of the metal material of the nozzle component. An optical periscope is incorporated to permit detailed visual inspection of the lining surface of the inner face of a reactor vessel. Data on the coordinates of defects are displayed on a TV screen and recorded and reproduced by a video recorder. The system also uses an 'echo method' for ultrasonic monitoring and a high sensitive 'tandem method' for detecting vertically oriented defects. The entire system can be operated by remote control. (Nogami, K.)

  14. Coupled thermo-mechanical analysis of corium-loaded lower head of pressure vessel

    International Nuclear Information System (INIS)

    Mishra, J.; Balasubramaniyan, V.

    2016-01-01

    A severe accident in the pressurised water reactor may lead to the relocation of core materials to the lower head of Reactor Pressure Vessel (RPV). The core debris at the bottom of RPV forms a melt pool of corium due to decay heat. The understanding of behaviour of pressure vessel, characterised by failure mode and time to failure, in this scenario is one of the important steps in predicting the accident progression. The most predominant failure mode is multi-axial creep deformation of the vessel with a non-uniform temperature field. Towards this, a numerical analysis methodology is developed for the prediction of pressure vessel deformation during the severe accidents. The methodology involves 2-D finite element modelling under multi-physics environment, which account the creep phenomena using Norton-Bailey creep law with a typical damage model of RPV material. The validation of the methodology is carried out using the results from OLHF experiment carried out in Sandia National Laboratory (SNL), USA, within the framework of an OECD. (author)

  15. Oxidation effect on steel corrosion and thermal loads during corium melt in-vessel retention

    Energy Technology Data Exchange (ETDEWEB)

    Granovsky, V.S.; Khabensky, V.B.; Krushinov, E.V.; Vitol, S.A.; Sulatsky, A.A.; Almjashev, V.I. [Alexandrov Scientific-Research Technology Institute (NITI), Sosnovy Bor (Russian Federation); Bechta, S.V. [KTH, Stockholm (Sweden); Gusarov, V.V. [SPb State Technology University (SPbGTU), St. Petersburg (Russian Federation); Barrachin, M. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), St Paul lez Durance (France); Bottomley, P.D., E-mail: paul.bottomley@ec.europa.eu [EC-Joint Research Centre, Institute for Transuranium Elements (ITU), Karlsruhe (Germany); Fischer, M. [AREVA GmbH, Erlangen (Germany); Piluso, P. [Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Cadarache, St Paul lez Durance (France)

    2014-10-15

    Highlights: • The METCOR facility simulates vessel steel corrosion in contact with corium. • Steel corrosion rates in UO{sub 2+x}–ZrO{sub 2}–FeO{sub y} coria accelerate above 1050 K. • However corrosion rates can also be limited by melt O{sub 2} supply. • The impact of this on in-vessel retention (IVR) strategy is discussed. - Abstract: During a severe accident with core meltdown, the in-vessel molten core retention is challenged by the vessel steel ablation due to thermal and physicochemical interaction of melt with steel. In accidents with oxidizing atmosphere above the melt surface, a low melting point UO{sub 2+x}–ZrO{sub 2}–FeO{sub y} corium pool can form. In this case ablation of the RPV steel interacting with the molten corium is a corrosion process. Experiments carried out within the International Scientific and Technology Center's (ISTC) METCOR Project have shown that the corrosion rate can vary and depends on both surface temperature of the RPV steel and oxygen potential of the melt. If the oxygen potential is low, the corrosion rate is controlled by the solid phase diffusion of Fe ions in the corrosion layer. At high oxygen potential and steel surface layer temperature of 1050 °C and higher, the corrosion rate intensifies because of corrosion layer liquefaction and liquid phase diffusion of Fe ions. The paper analyzes conditions under which corrosion intensification occurs and can impact on in-vessel melt retention (IVR)

  16. Operational Strategy of CBPs for load balancing of Operators in Advanced Main Control Room

    International Nuclear Information System (INIS)

    Kim, Seunghwan; Kim, Yochan; Jung, Wondea

    2014-01-01

    With the using of a computer-based control room in an APR1400 (Advanced Pressurized Reactor-1400), the operators' behaviors in the main control room had changed. However, though the working environment of operators has been changed a great deal, digitalized interfaces can also change the cognitive tasks or activities of operators. First, a shift supervisor (SS) can confirm/check the conduction of the procedures and the execution of actions of board operators (BOs) while confirming directly the operation variables without relying on the BOs. Second, all operators added to their work the use of a new CBP and Soft Controls, increasing their procedural workload. New operational control strategies of CBPs are necessary for load balancing of operator's task load in APR1400. In this paper, we compared the workloads of operators in an APR1400 who work with two different usages of the CBP. They are SS oriented usage and SS-BO collaborative usage. In this research, we evaluated the workloads of operators in an advanced main control room by the COCOA method. Two types of CBP usages were defined and the effects of these usages on the workloads were investigated. The obtained results showed that the workloads between operators in a control room can be balanced according to the CBP usages by assigning control authority to the operators

  17. Operational Strategy of CBPs for load balancing of Operators in Advanced Main Control Room

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seunghwan; Kim, Yochan; Jung, Wondea [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    With the using of a computer-based control room in an APR1400 (Advanced Pressurized Reactor-1400), the operators' behaviors in the main control room had changed. However, though the working environment of operators has been changed a great deal, digitalized interfaces can also change the cognitive tasks or activities of operators. First, a shift supervisor (SS) can confirm/check the conduction of the procedures and the execution of actions of board operators (BOs) while confirming directly the operation variables without relying on the BOs. Second, all operators added to their work the use of a new CBP and Soft Controls, increasing their procedural workload. New operational control strategies of CBPs are necessary for load balancing of operator's task load in APR1400. In this paper, we compared the workloads of operators in an APR1400 who work with two different usages of the CBP. They are SS oriented usage and SS-BO collaborative usage. In this research, we evaluated the workloads of operators in an advanced main control room by the COCOA method. Two types of CBP usages were defined and the effects of these usages on the workloads were investigated. The obtained results showed that the workloads between operators in a control room can be balanced according to the CBP usages by assigning control authority to the operators.

  18. Use of plant operating history to define transient loads

    International Nuclear Information System (INIS)

    Dwivedy, K.K.

    1996-01-01

    Fatigue and crack growth analyses of components subjected to transient loads have been under continuous development during the recent past to include effects of environment on the components. The accuracy of the evaluation method on the predicted reliability of the components in the operating environment has become a focus of attention. Methods have integrated available material/component test data to improve evaluation techniques. However, in the area of definition of thermal transient loads the analyst still has to remain conservative, because no realistic guidelines have been developed to define thermal transients and their sequences. Fatigue re-evaluations of components are becoming increasingly necessary in operating plants as they age due to two reasons: (1) Components show age related degradation and cannot be repaired/replaced due to economic/logistic reasons. (2) Components experience transient conditions which were not considered in the original design. In either case, the evaluation of remaining life of components involves definition of transients and their sequence from the time the component was put in service until the end of life. As a common practice, initial plant design transients are used in a conservative definition of sequences to obtain results unrealistic for the situation, which sometimes leads to inaccurate estimate of the remaining life of components. The objective of this paper is to use plant operating history and plant monitoring data to provide procedures and techniques to define realistic transients for evaluation

  19. Economic Aspects of Load Following in Flexible Operation. Annex IV

    International Nuclear Information System (INIS)

    2018-01-01

    To supplement this publication, the IAEA has prepared an economic study to quantify the cost–revenue aspects for nuclear power plant operations in mixed energy systems, including flexible operation. The purpose of this study was to explore economic opportunities for using nuclear energy in future power markets with increasing deployment of renewable energy, specifically investigating the following: — How much power ramping could future reactors support and at what penalty? — What type of flexibility is required on the grid — larger down power and faster ramp rate for load following or increased start/stop capability? What is the optimal level of flexible capacity in a system? — How can nuclear energy be used in different grid environments (e.g. different sizes or complexities) to cope with variable power demand and fluctuating supply from renewable energy sources? — What are the economic implications (including different revenue streams) for using large reactors? — How do market regulation and real market interaction affect the economic viability of using nuclear power under the various system modes? To answer these questions, an analytical case study approach, which directly assesses the difference between energy specific production costs for a baseload nuclear system and a load following nuclear system, was selected. Such a study, based on a large scale country level power plant dispatching model, could assess the difference between the total short term costs of producing a given amount of electricity by both types of operation in a particular system. This approach may answer the questions of whether adding flexible nuclear operation to the power system is capable of generating overall system benefits by minimizing total system costs at different levels. This annex briefly summarizes the IAEA study, together with insights from the available sources, and underlines the pressing needs in filling the missing knowledge gaps in the economic aspects of

  20. Neurocontrol of Pressurized Water Reactors in Load-Follow Operations

    International Nuclear Information System (INIS)

    Lin Chaung; Shen Chihming

    2000-01-01

    The neurocontrol technique was applied to control a pressurized water reactor (PWR) in load-follow operations. Generalized learning or direct inverse control architecture was adopted in which the neural network was trained off-line to learn the inverse model of the PWR. Two neural network controllers were designed: One provided control rod position, which controlled the axial power distribution, and the other provided the change in boron concentration, which adjusted core total power. An additional feedback controller was designed so that power tracking capability was improved. The time duration between control actions was 15 min; thus, the xenon effect is limited and can be neglected. Therefore, the xenon concentration was not considered as a controller input variable, which simplified controller design. Center target strategy and minimum boron strategy were used to operate the reactor, and the simulation results demonstrated the effectiveness and performance of the proposed controller

  1. Option of operating speed for vessels under low-carbon economy

    Directory of Open Access Journals (Sweden)

    Gang Li

    2013-03-01

    Full Text Available Purpose: To find out ships' optimum operating speed under low-carbon economy. Approach: First, it analyzes the relations between ship’s carbon emission and the operating speed, gets the optimum speed under which the entire fleet emit minimum carbon, then establishes the relations between the ship owner’s profit and the speed, extracts the speed under which the ship owner can gain the maximum profit and founds out it’s different from the speed under which the entire fleet emit minimum carbon. Findings: The government must take effective measures to make the ship owner slowdown and reduce emission. Originality: It first works out a balance point between the decrease of carbon emission brought by a lower operating speed and the increase of that caused by more vessels putting into service in a mathematical method.

  2. Flexible operation of a system of SPSs for load following

    Energy Technology Data Exchange (ETDEWEB)

    Collins, P.Q.; Tomkins, R.

    1984-04-01

    Major conclusions of previous studies on the SPS (solar power satellite) project - the proposal to collect solar energy in orbit and to transmit it to earth as a coherent microwave beam for reconversion to electricity - are that the system appears likely to be technically feasible, but that it will be economically feasible only if major reductions are made in the cost of certain subsystems, most notably in the fields of photovoltaic cells and in space transportation and operations. The former field is currently experiencing rapid advances, along with the rest of the semiconductor industry, while the achievement of the necessary cost targets in the latter field will depend on the development of a family of fully reusable space transportation vehicles as a successor to the present U.S. space shuttle. In order to assess the system's full economic potential it is also necessary to examine the most profitable means of operation. Most studies to date have assumed that, because of the SPS's high capital cost and the corresponding need to maximise its usage, each satellite would be used to transmit base load power more or less continuously to a single rectenna. However, this assumption overlooks the fact that the value of electric power is not constant but varies during the day and over the year. It therefore narrows the scope for SPS operation, and ignores a major part of the system's potential value. It also sets the most demanding cost targets for the SPS, since it would be in competition with other base-load plant with the lowest operating costs.

  3. Flexible operation of a system of SPSs for load following

    Energy Technology Data Exchange (ETDEWEB)

    Collins, P Q; Tomkins, R

    1984-04-01

    Major conclusions of previous studies on the SPS (solar power satellite) project - the proposal to collect solar energy in orbit and to transmit it to earth as a coherent microwave beam for reconversion to electricity - are that the system appears likely to be technically feasible, but that it will be economically feasible only if major reductions are made in the cost of certain subsystems, most notably in the fields of photovoltaic cells and in space transportation and operations. The former field is currently experiencing rapid advances, along with the rest of the semiconductor industry, while the achievement of the necessary cost targets in the latter field will depend on the development of a family of fully reusable space transportation vehicles as a successor to the present U.S. space shuttle. In order to assess the system's full economic potential it is also necessary to examine the most profitable means of operation. Most studies to date have assumed that, because of the SPS's high capital cost and the corresponding need to maximise its usage, each satellite would be used to transmit base load power more or less continuously to a single rectenna. However, this assumption overlooks the fact that the value of electric power is not constant but varies during the day and over the year. It therefore narrows the scope for SPS operation, and ignores a major part of the system's potential value. It also sets the most demanding cost targets for the SPS, since it would be in competition with other base-load plant with the lowest operating costs.

  4. Ultimate load analysis of prestressed concrete reactor pressure vessels considering a general material law

    International Nuclear Information System (INIS)

    Schimmelpfennig, K.

    1975-01-01

    A method of analysis is presented, by which progressive fracture processes in axisymmetric prestressed concrete pressure vessels during increasing internal pressure can be evaulated by means of a continuum calculation considering a general material law. Formulations used in the analysis concerning material behaviour are derived on one hand from appropriate results of testing small concrete specimens, and are on the other hand gained by parametric studies in order to solve questions still existing by recalulating fracture tests on concrete bodies with more complex states of stress. Due attention is focussed on investigating the behaviour of construction members subjected to high shear forces (end slabs.). (Auth.)

  5. The role of pressure vessel embrittlement in the long term operation of nuclear power plants

    International Nuclear Information System (INIS)

    Ballesteros, A.; Ahlstrand, R.; Bruynooghe, C.; Estorff, U. von; Debarberis, L.

    2012-01-01

    Highlights: ► Relevant open scientific issues for the long term operation of RPVs are discussed (flux effect, late blooming phases, etc.). ► Several European and American research programmes dealing with these open issues are reviewed. ► A method for consolidation and preservation of knowledge in this field is presented. - Abstract: The lack of new build of plants over the last twenty years has resulted in a switch within the industry from design, construction and development of new systems to the strengthening of safety systems and to the life extension, or long term operation (LTO), of existing reactors. The most relevant component of any nuclear power plan (NPP) is the reactor pressure vessel (RPV). This is because currently the RPV is still considered irreplaceable or prohibitively expensive to replace. This means, that if it degrades sufficiently, it could be the operational life limiting feature of the NPP. A RPV operational life of 60 years is being considered frequently by many utilities in their plant life management programmes. Areas of improvement facing long term operation are the reduction of uncertainties in the embrittlement parameters of irradiated vessels, and the development of embrittlement trend curves at high fluence levels, where surveillance data are scarce. Different techniques can be used to upgrade the surveillance programmes, as the use of miniature or reconstituted specimens and the application of best estimate assessment tools (e.g. Master Curve). Several relevant international research projects are on-going or have been proposed to clarify the material condition of long operated vessels. Knowledge management is a complementary tool, but not for it less important. The general context for LTO of RPVs is presented in this paper. Starting with a review of relevant embrittlement issues still open, followed by presenting the different techniques and tools that can be used to support LTO, and summarising the scopes of relevant European

  6. An effective surveillance strategy for reactor pressure vessel assessment in the long term operation perspective

    International Nuclear Information System (INIS)

    Chaouadi, R.; Gerard, R.

    2015-01-01

    The reactor pressure vessel (RPV) irradiation embrittlement is monitored by means of surveillance capsules containing the RPV belt-line materials, inserted inside the reactor pressure vessel (RPV) before the start of operation. These capsules are placed at location where they receive a higher neutron flux than the vessel wall, by a factor of the order of 2 to 3. They are regularly retrieved and tested to evaluate the RPV irradiation embrittlement according to specific regulatory procedures and standards, in order to guarantee the safe operation of the RPV throughout its lifetime. These procedures are often relying on empirical but conservative concepts. In parallel, material research reactor (MTR) irradiations are often used to support the surveillance data and to develop a better understanding of irradiation effects, not only qualitatively but also quantitatively. Taking advantage of the increased understanding of irradiation effects, analytical tools were developed to improve the evaluation embrittlement and quality assurance of the RPV embrittlement assessment. In this framework, an alternative but complementary surveillance program assessment was developed in Belgium, the so-called enhanced surveillance, in order to benefit from the latest developments in the area of materials science and irradiation effects. The neutron flux and fracture properties of the surveillance materials can be reliably characterized and correlated to each other using physically-based rather than empirical concepts. The enhanced surveillance approach is complementary to the mandatory regulatory procedure and allows quantifying the conservatism of the regulatory approach. The enhanced surveillance approach that uses the reconstitution technology to fabricate additional small size specimens, appropriate modeling tools and microstructural examination when required, makes it possible to rationalize all available information in a physically-based way

  7. Consideration of loading conditions initiated by thermal transients in PWR pressure vessels

    International Nuclear Information System (INIS)

    Azodi; Glahn; Kersting; Schulz; Jansky.

    1983-01-01

    This report describes the present state of PWR-plants in the Federal Republic of Germany with respect to - the design of the primary pressure boundary - the analysis of thermal transients and resulting loads - the material conditions and neutron fluence - the requirements for protection against fast fracture. The experimental and analytical research and development programs are delineated together with some foreign R and D programs. It is shown that the parameters investigated (loading condition, crack shape and orientation etc.) cover a broad range. Extensive analytical investigations are emphasized. (orig./RW) [de

  8. Operational aspects of the Calder Hall and Chapelcross pressure vessel ultrasonic inspections

    International Nuclear Information System (INIS)

    Bithell, S.J.; Howard, S.R.

    1993-01-01

    As a consequence of the NII's assessment of the Calder Hall and Chapelcross Long Term Safety Review, BNFplc were required to demonstrate the integrity of the Reactor Pressure Vessels through a programme of volumetric seam weld inspection. Existing equipment proved to be inadequate and necessitated the design and manufacture of a remote power manipulator and ultrasonic scanning package. Calder Hall Operations Department and Sellafield Technical Department, working closely with contract staff, completed the first stage of this technically demanding task within 14 months of the project's initiation, resulting in the first deployment of ''REDIMAN'' in March 1991. The design of the new equipment, and the technical and operational difficulties which were overcome by the Inspection Team are outlined. (author)

  9. Autonomous Cryogenics Loading Operations Simulation Software: Knowledgebase Autonomous Test Engineer

    Science.gov (United States)

    Wehner, Walter S., Jr.

    2013-01-01

    Working on the ACLO (Autonomous Cryogenics Loading Operations) project I have had the opportunity to add functionality to the physics simulation software known as KATE (Knowledgebase Autonomous Test Engineer), create a new application allowing WYSIWYG (what-you-see-is-what-you-get) creation of KATE schematic files and begin a preliminary design and implementation of a new subsystem that will provide vision services on the IHM (Integrated Health Management) bus. The functionality I added to KATE over the past few months includes a dynamic visual representation of the fluid height in a pipe based on number of gallons of fluid in the pipe and implementing the IHM bus connection within KATE. I also fixed a broken feature in the system called the Browser Display, implemented many bug fixes and made changes to the GUI (Graphical User Interface).

  10. Structural criteria for extreme dynamic internal pressure loadings of vessels and closure heads

    International Nuclear Information System (INIS)

    Bitner, J.L.

    1985-01-01

    The criteria protect against tensile plastic instability and local ductile rupture failure modes. To minimize the number of critical areas that may need more rigorous analytical methods, a screening criterion for limiting the membrane, bending and local stresses is defined. The stresses for this criterion are calculated from either simple and economical elastic dynamic or equivalent static methods. For the critical areas that remain, a strain-based criterion for strains derived from dynamic, inelastic methods is given. To assure that the criteria are properly applied, guidelines are outlined for controlling methods for deriving stresses and strains, for selecting appropriate material properties and for addressing specific dominating parameters that affect the validity of the analysis. The application of the criteria to a complex liquid metal fast breeder reactor vessel and closure head and the subsequent experimental verification of the results by several scale model experiments are summarized. (orig./HP)

  11. Structural evaluation of the Shippingport Reactor Pressure Vessel and Neutron Shield Tank package for impact and puncture loads

    International Nuclear Information System (INIS)

    Fischer, L.E.; Chou, C.K.; Lo, T.; Schwartz, M.W.

    1988-06-01

    A structural evaluation of Shippingport Reactor Pressure Vessel and Neutron Shield Tank package for impact and puncture loads under the normal and hypothetical accident conditions of 10 CFR 71 was performed. Component performance criteria for the Shippingport package and the corresponding structural acceptance criteria for these components were developed based on a review of the package geometry, the planned transport environment, and the external radiation standards and dispersal limits of 10 CFR 71. The evaluation was performed using structural analysis methods. A demonstration combining simplified model tests and nonlinear finite element analyses was made to substantiate the structural analysis methods used to evaluate the Shippingport package. The package was analyzed and the results indicate that the package meets external radiation standards and release limits of 10 CFR 71. 13 refs., 50 figs., 19 tabs

  12. Numerical studies of large penetrations and closures for containment vessels subjected to loadings beyond the design basis

    International Nuclear Information System (INIS)

    Kulak, R.F.; Hsieh, B.J.; Kennedy, J.M.; Ash, J.E.; McLennan, G.A.

    1984-01-01

    Numerical simulations of the macro-deformations of the sealing surfaces (gasketed junctures) of a PWR steel containment vessel's equipment hatch and a BWR Mk II containment vessel head have been performed. Results for the equipment hatch juncture indicate that the rotations of the hatch cover and penetration sleeve must be accounted for when performing leakage analysis because they can effect the compression of the gasket even though the gasket is in a pressure-seated configuration. Results from a leakage analysis indicated that excessive leakage can occur if the surface roughness is high and/or the compression set is high. Results for the Mk II head show that both the temperature and pressure loadings must be taken into account to obtain realistic responses. The temperature difference between the flanges and bolts has the important net effect of keeping the gasketed juncture closed, that is in metal-to-metal contact. Due to the high accident temperature, the gasket itself was found to achieve 100% compression set and thus could not perform its sealing function within the juncture

  13. 46 CFR 173.025 - Additional intact stability standards: Counterballasted vessels.

    Science.gov (United States)

    2010-10-01

    ...) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO VESSEL USE Lifting § 173.025 Additional intact stability standards: Counterballasted vessels. (a) Each vessel equipped to counterballast while lifting must be shown... loading and operation and at each combination of hook load and crane radius. (b) When doing the...

  14. Guidelines for prediction of irradiation embrittlement of operating WWER-440 reactor pressure vessels

    International Nuclear Information System (INIS)

    2005-06-01

    This TECDOC has been developed under an International Atomic Energy Agency Coordinated Research Project (CRP) entitled Evaluation of Radiation Damage of WWER Reactor Pressure Vessels (RPV) using Database on RPV Materials to develop the guidelines for prediction of radiation damage to WWER-440 PRVs. The WWER-440 RPV was designed by OKB Gidropress, Russian Federation, the general designer. Prediction of irradiation embrittlement of RPV materials is usually done in accordance with relevant codes and standards that are based on the large amounts of information from surveillance and research programmes. The existing Russian code (standard for strength calculations of components and piping in NPPs - PNAE G 7-002-86) for the WWER RPV irradiation embrittlement assessment was approved more than twenty years ago and based mostly on the experimental data obtained in research reactors with accelerated irradiation. Nevertheless, it is still in use and generally consistent with new data. The present publication presents the analyses using all available data required for more precise prediction of radiation embrittlement of WWER-440 RPV materials. Based on the fact that it contains a large amount of data from surveillance programmes as well as research programmes, the IAEA International Database on RPV Materials (IDRPVM) is used for the detailed analysis of irradiation embrittlement of WWER RPV materials. Using IDRPVM, the guideline is developed for assessment of irradiation embrittlement of RPV ferritic materials as a result of degradation during operation. Two approaches, i.e. transition temperatures based on Charpy impact notch toughness, as well as based on static fracture toughness tests, are used in RPV integrity evaluation. The objectives of the TECDOC are the analysis of irradiation embrittlement data for WWER- 440 RPV materials using IDRPVM database, evaluation of predictive formulae depending on chemical composition of the material, neutron fluence, flux, and

  15. Gamma dose rate estimation and operation management suggestions for decommissioning the reactor pressure vessel of HTR-PM

    Energy Technology Data Exchange (ETDEWEB)

    Sheng Fang; Hong Li; Jianzhu Cao; Wenqian Li; Feng Xie; Jiejuan Tong [Institute of Nuclear and New Energy Technology, Tsinghua, University, Beijing (China)

    2013-07-01

    China is now designing and constructing a high temperature gas cooled reactor-pebble bed module (HTR-PM). In order to investigate the future decommissioning approach and evaluate possible radiation dose, gamma dose rate near the reactor pressure vessel was calculated for different cooling durations using QAD-CGA program. The source term of this calculation was provided by KORIGEN program. Based on the calculated results, the spatial distribution and temporal changes of gamma dose rate near reactor pressure vessel was systematically analyzed. A suggestion on planning decommissioning operation of reactor pressure vessel of HTRPM was given based on calculated dose rate and the Chinese Standard GB18871-2002. (authors)

  16. Device for the simultaneous operation of the closing valve of a vessel and the closing valve of a transport container

    International Nuclear Information System (INIS)

    Tellier, Claude; Surriray, Michel.

    1982-01-01

    This device includes mechanisms for unlatching the closing valve of the vessel and securing it to the closing valve of the transport container and other mechanisms for vertically raising the assembly of valves, pivoting it and bringing it into a vertical position in a bulge provided in the bottom of the transport container. For example the first containment is a nuclear reactor vessel and the transport container is used for carrying an item from the vessel to an external area (for instance, a defective pump to the repair area) and for the return transport operation [fr

  17. A dynamic simulation to study NET in-vessel handling operations

    International Nuclear Information System (INIS)

    Fung, P.T.F.

    1989-01-01

    The inspection, maintenance and repair of the Next European Torus (NET) fusion machine will require the extensive use of remote handling equipment to minimise the human exposure to the high radiation environment. The use of efficient manipulators will reduce the NET downtime by reducing the preparation time for entry into the controlled area and by performing the task with reasonable area and by performing the task with reasonable dexterity and speed, consistent with safety. A high fidelity simulation is a valuable tool to assist in the manipulator design, operations, trajectory planning, parameter optimisation and system verification. A manipulator simulation package called ASAD was originally developed by Spar for space manipulator applications. It is now being adapted to simulate the in-Vessel HandlingUnit for the NET program. This terestrial version of ASAD has been name ASAD - T. Spar, through the services of the Canadian Fusion Fuels Technology Project, is under contract to the NET program for the performance of this activity. This paper describes the capabillities and underlying assumptions of ASAD - T, aling with description of the simulation development of the NET in-vessel manipulator. (author). 4 refs.; 7 figs

  18. Independent operation of implicit working memory under cognitive load.

    Science.gov (United States)

    Ji, Eunhee; Lee, Kyung Min; Kim, Min-Shik

    2017-10-01

    Implicit working memory (WM) has been known to operate non-consciously and unintentionally. The current study investigated whether implicit WM is a discrete mechanism from explicit WM in terms of cognitive resource. To induce cognitive resource competition, we used a conjunction search task (Experiment 1) and imposed spatial WM load (Experiment 2a and 2b). Each trial was composed of a set of five consecutive search displays. The location of the first four displays appeared as per pre-determined patterns, but the fifth display could follow the same pattern or not. If implicit WM can extract the moving pattern of stimuli, response times for the fifth target would be faster when it followed the pattern compared to when it did not. Our results showed implicit WM can operate when participants are searching for the conjunction target and even while maintaining spatial WM information. These results suggest that implicit WM is independent from explicit spatial WM. Copyright © 2017. Published by Elsevier Inc.

  19. Material properties for reactor pressure vessels and containment shells under dynamic loading

    International Nuclear Information System (INIS)

    Albertini, C.

    1997-01-01

    The effects of high strain rate, dynamic biaxial loading and deformation mode (tension, shear) on the mechanical properties of AISI 316 austenitic stainless steel in as-received and pre-damaged (creep, LCF) conditions are reported. This research was conducted to assess the performances of the containment shell of fast breeder reactors. The results of this research have been utilized to prepare similar investigations for SA 537 Class 1 ferritic steel used for the containment shell of LWR. The first results of these investigations are reported. A programme to study the mechanical properties of plain concrete with real size aggregate at high strain rate is described. (orig.)

  20. Structural integrity assessment of the reactor pressure vessel under the pressurized thermal shock loading

    International Nuclear Information System (INIS)

    Chen, Mingya; Lu, Feng; Wang, Rongshan; Ren, Ai

    2014-01-01

    Highlights: • The regulation and the code are proved to be conservative in the integrity assessment. • This study is helpful to understand the complex influence of the parameters. • The most dangerous case is given for the reference transient. - Abstract: Fracture mechanics analysis of pressurized thermal shock (PTS) is the key element of the integrity evaluation of the nuclear reactor pressure vessel (RPV). While the regulation of 10 CFR 50.61 and the ASME Code provide the guidance for the structural integrity, the guidance has been prepared under conservative assumptions. In this paper, the effects of conservative assumptions involved in the PTS analysis were investigated. The influence of different parameters, such as crack size, cladding effect and neutron fluence, were reviewed based on 3-D finite element analyses. Also, the sensitivity study of elastic–plastic approach, crack type and cladding thickness were reviewed. It was shown that crack depth, crack type, plastic effect and cladding thickness change the safety margin (SM) significantly, and the SM at the deepest point of the crack is not always smaller than that of the surface point, indicating that both the deepest and surface points of the crack front should be considered. For the reference transient, deeper cracks always give more conservative prediction. So compared to the prescribed analyses of a set of postulated defects with varying depths in the ASME code, it only needs to assess the crack with maximum depth in the code for the reference transient according to the conclusions

  1. Assessment of LWR piping design loading based on plant operating experience

    International Nuclear Information System (INIS)

    Svensson, P.O.

    1980-08-01

    The objective of this study has been to: (1) identify current Light Water Reactor (LWR) piping design load parameters, (2) identify significant actual LWR piping loads from plant operating experience, (3) perform a comparison of these two sets of data and determine the significance of any differences, and (4) make an evaluation of the load representation in current LWR piping design practice, in view of plant operating experience with respect to piping behavior and response to loading

  2. Contribution of the different erosion processes to material release from the vessel walls of fusion devices during plasma operation

    International Nuclear Information System (INIS)

    Behrisch, R.

    2002-01-01

    In high temperature plasma experiments several processes contribute to erosion and loss of material from the vessel walls. This material may enter the plasma edge and the central plasma where it acts as impurities. It will finally be re-deposited at other wall areas. These erosion processes are: evaporation due to heating of wall areas. At very high power deposition evaporation may become very large, which has been named ''blooming''. Large evaporation and melting at some areas of the vessel wall surface may occur during heat pulses, as observed in plasma devices during plasma disruptions. At tips on the vessel walls and/or hot spots on the plasma exposed solid surfaces electrical arcs between the plasma and the vessel wall may ignite. They cause the release of ions, atoms and small metal droplets, or of carbon dust particles. Finally, atoms from the vessel walls are removed by physical and chemical sputtering caused by the bombardment of the vessel walls with ions as well as energetic neutral hydrogen atoms from the boundary plasma. All these processes have been, and are, observed in today's plasma experiments. Evaporation can in principle be controlled by very effective cooling of the wall tiles, arcing is reduced by very stable plasma operation, and sputtering by ions can be reduced by operating with a cold plasma in front of the vessel walls. However, sputtering by energetic neutrals, which impinge on all areas of the vessel walls, is likely to be the most critical process because ions lost from the plasma recycle as neutrals or have to be refuelled by neutrals leading to the charge exchange processes in the plasma. In order to quantify the wall erosion, ''materials factors'' (MF) have been introduced in the following for the different erosion processes. (orig.)

  3. Adaptive Control System for Autonomous Helicopter Slung Load Operations

    DEFF Research Database (Denmark)

    Bisgaard, Morten; la Cour-Harbo, Anders; Bendtsen, Jan Dimon

    2010-01-01

    system on the helicopter that measures the position of the slung load. The controller is a combined feedforward and feedback scheme for simultaneous avoidance of swing excitation and active swing damping. Simulations and laboratory flight tests show the effectiveness of the combined control system......This paper presents design and verification of an estimation and control system for a helicopter slung load system. The estimator provides position and velocity estimates of the slung load and is designed to augment existing navigation in autonomous helicopters. Sensor input is provided by a vision......, yielding significant load swing reduction compared to the baseline controller....

  4. The nature of operating flight loads and their effect on propulsion system structures

    Science.gov (United States)

    Dickenson, K. H.; Martin, R. L.

    1981-01-01

    Past diagnostics studies revealed the primary causes of performance deterioration of high by-pass turbofan engines to be flight loads, erosion, and thermal distortion. The various types of airplane loads that are imposed on the engine throughout the lifetime of an airplane are examined. These include flight loads from gusts and maneuvers and ground loads from takeoff, landing, and taxi conditions. Clarification is made in definitions of the airframer's limit and ultimate design loads and the engine manufacturer's operating design loads. Finally, the influence of these loads on the propulsion system structures is discussed.

  5. Autonomous Cryogenic Load Operations: Knowledge-Based Autonomous Test Engineer

    Science.gov (United States)

    Schrading, J. Nicolas

    2013-01-01

    The Knowledge-Based Autonomous Test Engineer (KATE) program has a long history at KSC. Now a part of the Autonomous Cryogenic Load Operations (ACLO) mission, this software system has been sporadically developed over the past 20 years. Originally designed to provide health and status monitoring for a simple water-based fluid system, it was proven to be a capable autonomous test engineer for determining sources of failure in the system. As part of a new goal to provide this same anomaly-detection capability for a complicated cryogenic fluid system, software engineers, physicists, interns and KATE experts are working to upgrade the software capabilities and graphical user interface. Much progress was made during this effort to improve KATE. A display of the entire cryogenic system's graph, with nodes for components and edges for their connections, was added to the KATE software. A searching functionality was added to the new graph display, so that users could easily center their screen on specific components. The GUI was also modified so that it displayed information relevant to the new project goals. In addition, work began on adding new pneumatic and electronic subsystems into the KATE knowledge base, so that it could provide health and status monitoring for those systems. Finally, many fixes for bugs, memory leaks, and memory errors were implemented and the system was moved into a state in which it could be presented to stakeholders. Overall, the KATE system was improved and necessary additional features were added so that a presentation of the program and its functionality in the next few months would be a success.

  6. Autonomous Cryogenic Load Operations: KSC Autonomous Test Engineer

    Science.gov (United States)

    Shrading, Nicholas J.

    2012-01-01

    The KSC Autonomous Test Engineer (KATE) program has a long history at KSC. Now a part of the Autonomous Cryogenic Load Operations (ACLO) mission, this software system has been sporadically developed over the past 20+ years. Originally designed to provide health and status monitoring for a simple water-based fluid system, it was proven to be a capable autonomous test engineer for determining sources of failure in. the system, As part.of a new goal to provide this same anomaly-detection capability for a complicated cryogenic fluid system, software engineers, physicists, interns and KATE experts are working to upgrade the software capabilities and graphical user interface. Much progress was made during this effort to improve KATE. A display ofthe entire cryogenic system's graph, with nodes for components and edges for their connections, was added to the KATE software. A searching functionality was added to the new graph display, so that users could easily center their screen on specific components. The GUI was also modified so that it displayed information relevant to the new project goals. In addition, work began on adding new pneumatic and electronic subsystems into the KATE knowledgebase, so that it could provide health and status monitoring for those systems. Finally, many fixes for bugs, memory leaks, and memory errors were implemented and the system was moved into a state in which it could be presented to stakeholders. Overall, the KATE system was improved and necessary additional features were added so that a presentation of the program and its functionality in the next few months would be a success.

  7. Features wear nodes mechanization wing aircraft operating under dynamic loads

    Directory of Open Access Journals (Sweden)

    А.М. Хімко

    2009-03-01

    Full Text Available  The conducted researches of titanic alloy ВТ-22 at dynamic loading with cycled sliding and dynamic loading in conditions of rolling with slipping. It is established that roller jamming in the carriage increases wear of rod of mechanization of a wing to twenty times. The optimum covering for strengthening wearied sites and restoration of working surfaces of wing’s mechanization rod is defined.

  8. Method and system for connecting a loading buoy to a floating vessel. Fremgangsmte og system for tilkopling av en lastebye til et flytende farty

    Energy Technology Data Exchange (ETDEWEB)

    Breivik, K.; Kleppest, H.; Smedal, A.

    1994-07-04

    The invention deals with a method and a system for connecting a submerged loading/unloading buoy to a submerged receiving space in a floating vessel, for transfer of a medium, especially oil, to or from the vessel, wherein the buoy is anchored to the sea bed and is connected to a transfer line for medium. According to one variant of the method, a sink line is lowered from the vessel through the receiving space, an auxiliary buoy being attached to the sink line end, possible via an additional line, and the auxiliary buoy being caused to come to the water surface. A suitably marked pick-up line, which is connected to the buoy, is taken up and connected to the sink line, whereafter the vessel by a positioning means is moved into position above the submerged buoy and said lines are pulled up through the receiving space, so that the buoy is hoisted up and moved to a locking position therein, whereafter the buoy is locked in place in the receiving space. The vessel is provided with a hoisting means to hoist up said lines and the buoy, and also with a service shaft connecting the receiving space to the deck of the vessel. 9 figs.

  9. Rod behaviour under base load, load follow and frequency control operation: CYRANO 2 code predictions versus experimental results

    International Nuclear Information System (INIS)

    Gautier, B.; Raybaud, A.

    1984-01-01

    The French PWR reactors are now currently operating under load follow and frequency control. In order to demonstrate that these operating conditions were not able to increase the fuel failure rate, fuel rod behaviour calculations have been performed by E.D.F. with CYRANO 2 code. In parallel with these theoretical calculations, code predictions have been compared to experimental results. The paper presents some of the comparisons performed on 17x17 fuel irradiated in FESSENHEIM 2 up to 30 GWd/tU under base load operation and in the CAP reactor under load follow and frequency control conditions. It is shown that experimental results can be predicted with a reasonable accuracy by CYRANO 2 code. The experimental work was carried out under joint R and D programs by EDF, FRAGEMA, CEA, and WESTINGHOUSE (CAP program by French partners only). (author)

  10. Development of a Remotely-operated Visual Inspection System for Reactor Vessel Bottommounted Instrument Penetrations of KSNP and Lessons Learned

    International Nuclear Information System (INIS)

    Jeong, Kyungmin; Choi, Youngsu; Lee, Sunguk; Seo, Yongchil; Kang, Jong Gyu; Kim, Seungho; Jung, Seungho

    2006-01-01

    In April 2003, South Texas Project Unit 1 made a surprising discovery of boron acid leakage from two nozzles from a bare-metal examination of the reactor vessel bottom-mounted instrument penetrations during a routine refueling outage. A small powdery substance about 150mg was found on the outside of two instrument guide penetration nozzles on the bottom of the reactor. The primary coolant water of pressurized water reactors has caused cracking in penetrations with Alloy 600 through a process called primary water stress corrosion cracking. In South Korea, it is required to conduct 100% visual inspection of the outside of instrument guide penetration nozzles on the bottom of PWRs to confirm the integrity of reactor vessel. This paper describes the remotely-operated visual inspection systems for reactor vessel bottom-mounted instrument penetrations dispatched two times to Youngkwang NPPs and discusses the lessons learned

  11. The characterization of secondary lithium-ion battery degradation when operating complex, ultra-high power pulsed loads

    Science.gov (United States)

    Wong, Derek N.

    The US Navy is actively developing all electric fleets, raising serious questions about what is required of onboard power supplies in order to properly power the ship's electrical systems. This is especially relevant when choosing a viable power source to drive high power propulsion and electric weapon systems in addition to the conventional loads deployed aboard these types of vessels. Especially when high pulsed power loads are supplied, the issue of maintaining power quality becomes important and increasingly complex. Conventionally, a vessel's electrical power is generated using gas turbine or diesel driven motor-generator sets that are very inefficient when they are used outside of their most efficient load condition. What this means is that if the generator is not being utilized continuously at its most efficient load capacity, the quality of the output power may also be effected and fall outside of the acceptable power quality limits imposed through military standards. As a solution to this potential problem, the Navy has proposed using electrochemical storage devices since they are able to buffer conventional generators when the load is operating below the generator's most efficient power level or able to efficiently augment a generator when the load is operating in excess of the generator's most efficient power rating. Specifically, the US Navy is interested in using commercial off-the-shelf (COTS) lithium-ion batteries within an intelligently controlled energy storage module that could act as either a prime power supply for on-board pulsed power systems or as a backup generator to other shipboard power systems. Due to the unique load profile of high-rate pulsed power systems, the implementation of lithium-ion batteries within these complex systems requires them to be operated at very high rates and the effects these things have on cell degradation has been an area of focus. There is very little published research into the effects that high power transient

  12. Design concept for vessels and heat exchangers

    International Nuclear Information System (INIS)

    Elfmann, W.; Ferrari, L.D.B.

    1981-01-01

    A design concept for vessels and heat exchangers against internal and external loads resulting from normal operation and accident is shown. A definition and explanation of the operating conditions and stress levels are given. A description of the type of analysis (stress, fatigue, deformation, stability, earthquake and vibration) is presented in detail, also including technical guidelines which are used for the vessels and heat exchangers and their individual structure parts. (Author) [pt

  13. Improvement of daily load-following operation for boiling water reactors

    International Nuclear Information System (INIS)

    Kiguchi, Takashi; Kurihara, Kunitoshi; Sakurai, Mikio; Joge, Toshio; Asami, Kazuo.

    1980-01-01

    Recently, with the increase of the proportion of nuclear power generation to the total amount of power generation of electric power systems, the needs of daily load-following operation of nuclear power stations have heightened, accordingly the study on the method of daily load-following operation has been carried out for BWRs. In this study, by the combined use of the flow rate control of core coolnat being operated easily and the operation of control rods, the BWR system with the daily load-following performance of 100% power output in daytime and 50% power output at night was the target of development. For the purpose, the change of core characteristics during load-following was grasped analytically, and the range of load change was investigated. At the same time, as the first stage of developing operation control and monitoring system, the reactor output-adjusting device which makes generator output automatically follow the target load change pattern by the flow rate control of core coolnat, and the equipment for monitoring core performance on line were developed. The analysis of the method of daily load-following operation in present-day BWRs, the study on the improvement of load-following operation performance, the reactor output-adjusting device are described. (Kako, I.)

  14. Assessment of Ultimate Load Capacity for Pre-Stressed Concrete Containment Vessel Model of PWR Design With BARC Code ULCA

    International Nuclear Information System (INIS)

    Basha, S.M.; Singh, R.K.; Patnaik, R.; Ramanujam, S.; Kushwaha, H.S.; Venkat Raj, V.

    2002-01-01

    Ultimate load capacity assessment of nuclear containments has been a thrust research area for Indian Pressurised Heavy Water Reactor (PHWR) power programme. For containment safety assessment of Indian PHWRs a finite element code ULCA was developed at BARC, Trombay. This code has been extensively benchmarked with experimental results. The present paper highlights the analysis results for Prestressed Concrete Containment Vessel (PCCV) tested at Sandia National Labs, USA in a Round Robin analysis activity co-sponsored by Nuclear Power Engineering Corporation (NUPEC), Japan and the U.S Nuclear Regulatory Commission (NRC). Three levels of failure pressure predictions namely the upper bound, the most probable and the lower bound (all with 90% confidence) were made as per the requirements of the round robin analysis activity. The most likely failure pressure is predicted to be in the range of 2.95 Pd to 3.15 Pd (Pd= design pressure of 0.39 MPa for the PCCV model) depending on the type of liners used in the construction of the PCCV model. The lower bound value of the ultimate pressure of 2.80 Pd and the upper bound of the ultimate pressure of 3.45 Pd are also predicted from the analysis. These limiting values depend on the assumptions of the analysis for simulating the concrete-tendon interaction and the strain hardening characteristics of the steel members. The experimental test has been recently concluded at Sandia Laboratory and the peak pressure reached during the test is 3.3 Pd that is enveloped by our upper bound prediction of 3.45 Pd and is close to the predicted most likely pressure of 3.15 Pd. (authors)

  15. Emergency Load Shedding Strategy Based on Sensitivity Analysis of Relay Operation Margin against Cascading Events

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Sun, Haishun Sun

    2012-01-01

    the runtime emergent states of related system component. Based on sensitivity analysis between the relay operation margin and power system state variables, an optimal load shedding strategy is applied to adjust the emergent states timely before the unwanted relay operation. Load dynamics is also taken...... into account to compensate load shedding amount calculation. And the multi-agent technology is applied for the whole strategy implementation. A test system is built in real time digital simulator (RTDS) and has demonstrated the effectiveness of the proposed strategy.......In order to prevent long term voltage instability and induced cascading events, a load shedding strategy based on the sensitivity of relay operation margin to load powers is discussed and proposed in this paper. The operation margin of critical impedance backup relay is defined to identify...

  16. Expert System Models for Forecasting Forklifts Engagement in a Warehouse Loading Operation: A Case Study

    Directory of Open Access Journals (Sweden)

    Dejan Mirčetić

    2016-08-01

    Full Text Available The paper focuses on the problem of forklifts engagement in warehouse loading operations. Two expert system (ES models are created using several machine learning (ML models. Models try to mimic expert decisions while determining the forklifts engagement in the loading operation. Different ML models are evaluated and adaptive neuro fuzzy inference system (ANFIS and classification and regression trees (CART are chosen as the ones which have shown best results for the research purpose. As a case study, a central warehouse of a beverage company was used. In a beverage distribution chain, the proper engagement of forklifts in a loading operation is crucial for maintaining the defined customer service level. The created ES models represent a new approach for the rationalization of the forklifts usage, particularly for solving the problem of the forklifts engagement incargo loading. They are simple, easy to understand, reliable, and practically applicable tool for deciding on the engagement of the forklifts in a loading operation.

  17. Variability of extreme flap loads during turbine operation

    Energy Technology Data Exchange (ETDEWEB)

    Ronold, K O [Det Norske Veritas, Hoevik (Norway); Larsen, G C [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

    1999-03-01

    The variability of extreme flap loads is of utmost importance for design of wind-turbine rotor blades. The flap loads of interest consist of the flap-wise bendin moment response at the blade root whose variability in the short-term, for a given wind climate, can be represented by a stationary process. A model for the short-term bending moment process is presented, and the distribution of its associated maxima is derived. A model for the wind climate is given in terms of the probability distributions for the 10-minute mean wind speed and the standard deviation of the arbitrary wind speed. This is used to establish the distribution of the largest flap-wise bending moment in a specific reference period, and it is outlined how a characteristic bending moment for use in design can be extracted from this distribution. The application of the presented distribution models is demonstrated by a numerical example for a site-specific wind turbine. (au)

  18. A Bankruptcy Problem Approach to Load-shedding in Multiagent-based Microgrid Operation

    OpenAIRE

    Kim, Hak-Man; Kinoshita, Tetsuo; Lim, Yujin; Kim, Tai-Hoon

    2010-01-01

    A microgrid is composed of distributed power generation systems (DGs), distributed energy storage devices (DSs), and loads. To maintain a specific frequency in the islanded mode as an important requirement,  the control of DGs’ output and charge action of DSs are used in supply surplus conditions and load-shedding and discharge action of DSs are used in supply shortage conditions. Recently, multiagent systems for autonomous microgrid operation have been studied. Especially, load-shedding, whi...

  19. Assessment of Workers' Exposure to Grain Dust and Bioaerosols During the Loading of Vessels' Hold: An Example at a Port in the Province of Québec.

    Science.gov (United States)

    Marchand, Geneviève; Gardette, Marie; Nguyen, Kiet; Amano, Valérie; Neesham-Grenon, Eve; Debia, Maximilien

    2017-08-01

    Longshoremen are exposed to large amounts of grain dust while loading of grain into the holds of vessels. Grain dust inhalation has been linked to respiratory diseases such as chronic bronchitis, hypersensitivity, pneumonitis, and toxic pneumonitis. Our objective was to characterize the exposure of longshoremen to inhalable and total dust, endotoxins, and cultivable bacteria and fungi during the loading of grain in a vessel's hold at the Port of Montreal in order to assess the potential health risks. Sampling campaigns were conducted during the loading of two different types of grain (wheat and corn). Environmental samples of microorganisms (bacteria, fungus, and actinomycetes) were taken near the top opening of the ship's holds while personal breathing zone measurements of dust and endotoxins were sampled during the worker's 5-hour shifts. Our study show that all measurements are above the recommendations with concentration going up to 390 mg m-3 of total dust, 89 mg m-3 of inhalable fraction, 550 000 EU m-3 of endotoxins, 20 000 CFU m-3 of bacteria, 61 000 CFU m-3 of fungus and 2500 CFU m-3 of actinomycetes. In conclusion, longshoremen are exposed to very high levels of dust and of microorganisms and their components during grain loading work. Protective equipment needs to be enforced for all workers during such tasks in order to reduce their exposure. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  20. Joint High Speed Vessel (JHSV) Follow on Operational Test and Evaluation (FOT and E) Report

    Science.gov (United States)

    2015-09-21

    problem by fabricating new lines that included surge pendants . These new lines allow some limited movement of the two, skin-to-skin moored vessels... bridge . Figure 9. SSDG Number 2, USNS Spearhead Figure 10. Flame Face Surface Pictures of SSDG Cylinder Head 15 Figure 11

  1. 46 CFR 105.45-1 - Loading or dispensing petroleum products.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Loading or dispensing petroleum products. 105.45-1... VESSELS COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Special Operating Requirements § 105.45-1 Loading or dispensing petroleum products. (a) A commercial fishing vessel must have aboard a letter of...

  2. Expected load spectra of prototype Francis turbines in low-load operation using numerical simulations and site measurements

    Science.gov (United States)

    Eichhorn, M.; Taruffi, A.; Bauer, C.

    2017-04-01

    The operators of hydropower plants are forced to extend the existing operating ranges of their hydraulic machines to remain competitive on the energy market due to the rising amount of wind and solar power. Faster response times and a higher flexibility towards part- and low-load conditions enable a better electric grid control and assure therefore an economic operation of the power plant. The occurring disadvantage is a higher dynamic excitation of affected machine components, especially Francis turbine runners, due to pressure pulsations induced by unsteady flow phenomena (e.g. draft tube vortex ropes). Therefore, fatigue analysis becomes more important even in the design phase of the hydraulic machines to evaluate the static and dynamic load in different operating conditions and to reduce maintenance costs. An approach including a one-way coupled fluid-structure interaction has been already developed using unsteady CFD simulations and transient FEM computations. This is now applied on two Francis turbines with different specific speeds and power ranges, to obtain the load spectra of both machines. The results are compared to strain gauge measurements on the according Francis turbines to validate the overall procedure.

  3. To selecting the characteristics of saturated steam direct cycle NPPs for operation under variable loads

    International Nuclear Information System (INIS)

    Khrustalev, V.A.; Demidov, O.I.

    1986-01-01

    Problems for operating process optimization of NPPs with RBMK type reactors under load swings in the power system is considered. Determination technique for optimal values of such parameters as initial steam pressure and fuel enrichment for NPP different load factors is developed. Optimization of these parameters gives a 150000 rouble saving of annual expenditures per each 3200 MW of reactor heat output

  4. 30 CFR 77.1607 - Loading and haulage equipment; operation.

    Science.gov (United States)

    2010-07-01

    ... operation. (l) Tires shall be deflated before repairs on them are started and adequate means shall be provided to prevent wheel locking rims from creating a hazard during tire inflation. (m) Electrically... to prevent conveyors from running in reverse if a hazard to personnel would be caused. (ee) Aerial...

  5. Load follow operation in nuclear power plants and its influence on PWR fuel behaviour

    International Nuclear Information System (INIS)

    Nagino, Y.; Miyazaki, Y.

    1980-01-01

    The contribution of nuclear power generation to our company's grid system is becoming greater each year, which makes it necessary to operate nuclear power plants with load follow mode in the near future. (author)

  6. Changes in the Strength of the Polymer Concrete Used in the Electroplating Vats Under Operational Load

    Directory of Open Access Journals (Sweden)

    Radna Lidia

    2017-12-01

    Full Text Available Due to the strong and aggressive electrolyte media and thermal load, design of the electroplating vats in the copper industry often relies on the resin concrete. The article presents the results of the strength tests of the polymer concrete based on the "Derakane" resin, used in the construction of electroplating vats. Samples were taken from the real vats - both new and 17-year old. Strength tests included compression and bending tensile strength test. To assess the effect of operational conditions the tests were performed on the same-age vats, some of which were never used while others were subjected to the operational load. During the operation, the vats sustained load of the anode and cathode weights, cyclic electrolyte loading with a temperatures up to 60°C. As a result, it was noted that the operational conditions led to the increased strength of the polymer concrete material.

  7. Changes in the Strength of the Polymer Concrete Used in the Electroplating Vats Under Operational Load

    Science.gov (United States)

    Radna, Lidia; Sakharov, Volodymyr

    2017-12-01

    Due to the strong and aggressive electrolyte media and thermal load, design of the electroplating vats in the copper industry often relies on the resin concrete. The article presents the results of the strength tests of the polymer concrete based on the "Derakane" resin, used in the construction of electroplating vats. Samples were taken from the real vats - both new and 17-year old. Strength tests included compression and bending tensile strength test. To assess the effect of operational conditions the tests were performed on the same-age vats, some of which were never used while others were subjected to the operational load. During the operation, the vats sustained load of the anode and cathode weights, cyclic electrolyte loading with a temperatures up to 60°C. As a result, it was noted that the operational conditions led to the increased strength of the polymer concrete material.

  8. Identification of critical equipment and determination of operational limits in helium refrigerators under pulsed heat load

    Science.gov (United States)

    Dutta, Rohan; Ghosh, Parthasarathi; Chowdhury, Kanchan

    2014-01-01

    Large-scale helium refrigerators are subjected to pulsed heat load from tokamaks. As these plants are designed for constant heat loads, operation under such varying load may lead to instability in plants thereby tripping the operation of different equipment. To understand the behavior of the plant subjected to pulsed heat load, an existing plant of 120 W at 4.2 K and another large-scale plant of 18 kW at 4.2 K have been analyzed using a commercial process simulator Aspen Hysys®. A similar heat load characteristic has been applied in both quasi steady state and dynamic analysis to determine critical stages and equipment of these plants from operational point of view. It has been found that the coldest part of both the cycles consisting JT-stage and its preceding reverse Brayton stage are the most affected stages of the cycles. Further analysis of the above stages and constituting equipment revealed limits of operation with respect to variation of return stream flow rate resulted from such heat load variations. The observations on the outcome of the analysis can be used for devising techniques for steady operation of the plants subjected to pulsed heat load.

  9. First Full Beam Loading Operation with the CTF3 Linac

    CERN Multimedia

    Corsini, R; Bienvenu, G; Braun, H; Carron, G; Ferrari, A; Forstner, O; Garvey, Terence; Geschonke, Günther; Groening, L; Jensen, E; Koontz, R; Lefèvre, T; Miller, R; Rinolfi, Louis; Roux, R; Ruth, Ronald D; Schulte, Daniel; Tecker, F A; Thorndahl, L; Yeremian, A D

    2004-01-01

    The aim of the CLIC (Compact Linear Collider) Study is to investigate the feasibility of a high luminosity, multi-TeV linear e+e- collider. CLIC is based on a two-beam method, in which a high current drive beam is decelerated to produce 30 GHz RF power needed for high-gradient acceleration of the main beam running parallel to it. To demonstrate the outstanding feasibility issues of the scheme a new CLIC Test Facility, CTF3, is being constructed at CERN by an international collaboration. In its final configuration CTF3 will consist of a 150 MeV drive beam linac followed by a 42 m long delay loop and an 84 m combiner ring. The installation will include a 30 GHz high power test stand, a representative CLIC module and a test decelerator. The first part of the linac was installed and commissioned with beam in 2003. The first issue addressed was the generation and acceleration of a high-current drive beam in the "full beam loading" condition where RF power is converted into beam power with an efficiency of more tha...

  10. Control of power distribution and the safety of a WWER-1000 reactor during operation in a load-following regime

    International Nuclear Information System (INIS)

    Filipchuk, E.V.; Dunaev, V.G.; Luk'yanets, I.A.; Potapenko, P.T.; Timokhin, E.S.; Voznesenskij, V.A.; Mitin, V.I.

    1984-01-01

    An important task in ensuring the operational safety of a nuclear power plant with a vessel-type water-cooled, water-moderated reactor is the development of algorithms for controlling power distribution in base-load and load-following regimes. The control strategy must ensure that the form of power distribution is maintained within the permissible limits in the case of situations presenting a nuclear hazard and of xenon fluctuations when there are variations in power output. The task of controlling power distribution can be broken down into an axial problem and a radial-azimuthal problem. For maintenance of the form of axial power distribution an algorithm of optimum fast-action control is proposed; for maintenance of the radial-azimuthal form, an algorithm of optimum (i.e. best) approximation to the given distribution of control. The two control problems are solved by using a single computerized procedure based on mathematical programming. The algorithms are designed for use in computerized control. The paper presents the results of algorithm simulation. The authors propose that in the first stage, activation of the control systems should involve the operator, who can view the sequence of actions on a display screen. (author)

  11. Operating experience with high beam currents and transient beam loading in the SLC damping rings

    International Nuclear Information System (INIS)

    Minty, M.G.; Akre, R.; Krejcik, P.; Siemann, R.H.

    1995-01-01

    During the 1994 SLC run the nominal operating intensity in the damping rings was raised from 3.5 x 10 10 to greater than 4 x 10 10 particles per bunch (ppb). Stricter regulation of rf system parameters was required to maintain stability of the rf system and particle beam. Improvements were made in the feedback loops which control the cavity amplitude and loading angles. Compensation for beam loading was also required to prevent klystron saturation during repetition rate changes. To minimize the effects of transient loading on the rf system, the gain of the direct rf feedback loop and the loading angles were optimized

  12. Stress analysis of LOFT containment vessel attachments for the mainsteam and feedwater piping support structures

    International Nuclear Information System (INIS)

    Finicle, D.P.

    1977-01-01

    The LOFT Containment Vessel attachments for the Mainsteam and Feedwater Piping Support Structures have been analyzed for operating and faulted loading conditions. This report contains the analysis of the connections to the containment vessel for the most current design and loading. Also contained in this report is the analysis of the piping supports

  13. Status and Perspectives of Nuclear Reactor Pressure Vessel Life Extension up to 60 Years Operation in Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Chaouadi, R.; Scibetta, M.; Van Walle, E.

    2009-09-15

    The scope of this report involves a safety evaluation of the reactor pressure vessel (RPV) against neutron embrittlement, in the most severely irradiation region (belt line) and in the event of a pressurized thermal shock. The irreplaceable RPV is considered to be the most critical component for lifetime considerations of the nuclear power plant. However, an application for operation extension will also depend upon a number of additional considerations, including the technical assessment of other plant components, as well as non-technical arguments (e.g. political, environmental, economical, strategical that are outside the scope this report. In the hypothesis of a request for operation extension, it is the responsibility of the utilities to provide the safety authorities with an exhaustive dossier demonstrating that safe extended operation is guaranteed. The role of the safety authorities is to critically evaluate the safety dossier for eventually granting the operation extension.

  14. Status and Perspectives of Nuclear Reactor Pressure Vessel Life Extension up to 60 Years Operation in Belgium

    International Nuclear Information System (INIS)

    Lucon, E.; Chaouadi, R.; Scibetta, M.; Van Walle, E.

    2009-01-01

    The scope of this report involves a safety evaluation of the reactor pressure vessel (RPV) against neutron embrittlement, in the most severely irradiation region (belt line) and in the event of a pressurized thermal shock. The irreplaceable RPV is considered to be the most critical component for lifetime considerations of the nuclear power plant. However, an application for operation extension will also depend upon a number of additional considerations, including the technical assessment of other plant components, as well as non-technical arguments (e.g. political, environmental, economical, strategical that are outside the scope this report. In the hypothesis of a request for operation extension, it is the responsibility of the utilities to provide the safety authorities with an exhaustive dossier demonstrating that safe extended operation is guaranteed. The role of the safety authorities is to critically evaluate the safety dossier for eventually granting the operation extension.

  15. Boron mixing transients in a 900 MW PWR vessel for a reactor start-up operation

    International Nuclear Information System (INIS)

    Alvarez, D.; Martin, A.; Schneider, J.P.

    1995-01-01

    In 1991 a R and D action, based on numerical simulations and experiments on PWRs'S primary coolant temperature or boron mixing capabilities, was initiated. This paper presents the test facility BORA-BORA (a 1/5th scaled mock-up of a 900 MW PWR vessel) and the Thermalhydraulic Finite Element Code N3S used for 3D calculations performed on the accurate geometry of the plant. As a validation test case of these experimental and numerical tools, we present the results obtained on the primary coolant mixing capabilities in the vessel with the three loops balanced in mass flow rate. The second part of this report deals with the mixing of a clear water plug in the vessel when a primary coolant pump start-up. The results are obtained in the mock-up in terms of boron concentration at the core inlet for several clear water plug volumes. The numerical results give the complete fluid flow and boron concentration patterns but comparisons were made at the core inlet. (author). 15 refs., 9 figs., 1 tab

  16. TPE upgrade for enhancing operational safety and improving in-vessel tritium inventory assessment in fusion nuclear environment

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, M., E-mail: Masashi.Shimada@inl.gov [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Taylor, C.N.; Moore-McAteer, L.; Pawelko, R.J. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Kolasinski, R.D.; Buchenauer, D.A. [Sandia National Laboratories, Hydrogen and Materials Science Department, Livermore, CA 94550 (United States); Cadwallader, L.C.; Merrill, B.J. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

    2016-11-01

    The Tritium Plasma Experiment (TPE) is a unique high-flux linear plasma device that can handle beryllium, tritium, and neutron-irradiated plasma facing materials, and is the only existing device dedicated to evaluate in-vessel tritium inventory in the nuclear environment for fusion safety. The electrical upgrade were recently carried out to enhance operational safety and to improve plasma performance. New DC power supplies and a new control center enable remote plasma operations from outside of the contamination area for tritium, minimizing the possible exposure risk with tritium and beryllium and eliminating heat stress issue. In November 2015, the TPE successfully achieved first deuterium plasma via remote operation after a significant three-year upgrade. Simple linear scaling estimate showed that the TPE is expected to achieve Γ{sub i}{sup max} of >1.0 × 10{sup 23} m{sup −2} s{sup −1} and q{sub heat} of >1 MW m{sup −2} with new power supplies. This upgrade not only improves operational safety of the worker, but also enhances plasma performance to better simulate extreme plasma-material conditions expected in ITER, FNSF, and DEMO for improving in-vessel tritium inventory assessment in fusion nuclear environment.

  17. Studies on representative disruption scenarios, associated electromagnetic and heat loads and operation window in ITER

    International Nuclear Information System (INIS)

    Fujieda, Hirobumi; Shimada, Michiya; Kawano, Yasunori; Ohmori, Junji; Neyatani, Yuzuru; Sugihara, Masayoshi; Gribov, Yuri; Ioki, Kimihiro; Khayrutdinov, Rustan; Lukash, Victor

    2007-07-01

    The impacts of plasma disruptions on ITER have been investigated in detail to confirm the robustness of the design of the machine to the potential consequential loads. The loads include both electromagnetic (EM) and heat loads on the in-vessel components and the vacuum vessel (VV). Several representative disruption scenarios are specified based on newly derived physics guidelines for the shortest current quench time as well as the maximum product of halo current fraction and toroidal peaking factor arising from disruptions in ITER. Disruption simulations with the DINA code and EM load analyses with a 3D finite element method (FEM) code are performed for these scenarios. Some margins are confirmed in the EM load on in-vessel components due to induced eddy and halo currents for these representative scenarios. However, the margins are not very large. The heat load on various parts of the first wall due to the vertical movement and the thermal quench (TQ) is calculated with a 2D heat conduction code based on the database of heat deposition during disruptions and simulation results with the DINA code. It is found that the beryllium (Be) wall will not melt during the vertical movement. Significant melting is anticipated for the upper Be wall and tungsten divertor baffle due to the TQ after the vertical movement. However, its impact could be substantially mitigated by implementing a reliable detection system of the vertical movement and a mitigation system, e.g., massive noble gas injection (MGI). Some melting of the upper Be wall is anticipated at major disruptions (MD). At least several tens of unmitigated disruptions must be considered even if an advanced prediction/mitigation system is implemented. With these unmitigated disruptions, the loss of Be layer is expected to be within approx. = 30-100 μm/event out of 10 mm thick Be first wall. Various post processing programs of the results simulated with the DINA code, which are developed for the design work, are

  18. Thermal–mechanical stress analysis of pressurized water reactor pressure vessel with/without a preexisting crack under grid load following conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish, E-mail: smohanty@anl.gov; Soppet, William K.; Majumdar, Saurin; Natesan, Krishnamurti

    2016-12-15

    Highlights: • Use of intermittent renewable-energy source in power grid is becoming a trend. • Gird load-following can leads to variable power demand from Nuclear power plant. • Reactor components can be stressed differently under gird load-following mode. • Estimation of stress–strain state under grid load-following condition is essential. - Abstract: In this paper, we present thermal–mechanical stress analysis of a pressurized water reactor pressure vessel and its hot-leg and cold-leg nozzles. Results are presented from thermal and thermal–mechanical stress analysis under reactor heat-up, cool-down, and grid load-following conditions. Analysis results are given with and without the presence of preexisting crack in the reactor nozzle (axial crack in hot leg nozzle). From the model results it is found that the stress–strain states are significantly higher in case of presence of crack than without crack. The stress–strain state under grid load following condition are more realistic compared to the stress–strain state estimated assuming simplified transients.

  19. Thermal–mechanical stress analysis of pressurized water reactor pressure vessel with/without a preexisting crack under grid load following conditions

    International Nuclear Information System (INIS)

    Mohanty, Subhasish; Soppet, William K.; Majumdar, Saurin; Natesan, Krishnamurti

    2016-01-01

    Highlights: • Use of intermittent renewable-energy source in power grid is becoming a trend. • Gird load-following can leads to variable power demand from Nuclear power plant. • Reactor components can be stressed differently under gird load-following mode. • Estimation of stress–strain state under grid load-following condition is essential. - Abstract: In this paper, we present thermal–mechanical stress analysis of a pressurized water reactor pressure vessel and its hot-leg and cold-leg nozzles. Results are presented from thermal and thermal–mechanical stress analysis under reactor heat-up, cool-down, and grid load-following conditions. Analysis results are given with and without the presence of preexisting crack in the reactor nozzle (axial crack in hot leg nozzle). From the model results it is found that the stress–strain states are significantly higher in case of presence of crack than without crack. The stress–strain state under grid load following condition are more realistic compared to the stress–strain state estimated assuming simplified transients.

  20. Contribution of materials investigations and operating experience of reactor vessel internals to PWRs' safety, performance and reliability

    International Nuclear Information System (INIS)

    Lemaire, E.; Monteil, N.; Jardin, N.; Doll, M.

    2015-01-01

    The Reactor Pressure Vessel Internals (RVI) include all the components inside the pressure vessel, except the nuclear fuel, the rod cluster assemblies and the instrumentation. The RVI consist of bolted and welded structures that are divided into two sub-assemblies: the upper internals which are removed at every refueling outage and the lower internals which are systematically removed for inspection at every 10-year outage. The main functions of the RVI are to position the core, to support it, and to provide a coolant flow by channeling the fluid. Moreover, the lower internals contribute to a neutron protection of the reactor pressure vessel by absorbing most of the neutron flux from the core. Depending on their location and material composition, the RVI components can face different ageing phenomena, that are actual or potential (such as wear, fatigue, stress corrosion cracking, irradiation assisted stress corrosion cracking, hardening and loss of ductility due to neutron irradiation, irradiation creep and irradiation swelling). EDF has developed a strategy for managing ageing and demonstrating the capacity of the RVI to perform their design functions over 40 years of operation. This overall approach is periodically revisited to take into account the most recent knowledge obtained from the following main topics: Safety Analyses, Research-Development programs, In-Service Inspection (ISI) results, Maintenance programs and Metallurgical Examinations. Based on continuous improvements in those fields, the goal of this paper is to present the way that materials investigations and operating experience obtained on RVI are managed by EDF to improve RVI safety, performance and reliability. It is shown that a perspective of 60 years of operation of RVI components is supported by large Research-Development efforts combined with field experience. (authors)

  1. Distributed situation awareness in complex collaborative systems: A field study of bridge operations on platform supply vessels.

    Science.gov (United States)

    Sandhåland, Hilde; Oltedal, Helle A; Hystad, Sigurd W; Eid, Jarle

    2015-06-01

    This study provides empirical data about shipboard practices in bridge operations on board a selection of platform supply vessels (PSVs). Using the theoretical concept of distributed situation awareness, the study examines how situation awareness (SA)-related information is distributed and coordinated at the bridge. This study thus favours a systems approach to studying SA, viewing it not as a phenomenon that solely happens in each individual's mind but rather as something that happens between individuals and the tools that they use in a collaborative system. Thus, this study adds to our understanding of SA as a distributed phenomenon. Data were collected in four field studies that lasted between 8 and 14 days on PSVs that operate on the Norwegian continental shelf and UK continental shelf. The study revealed pronounced variations in shipboard practices regarding how the bridge team attended to operational planning, communication procedures, and distracting/interrupting factors during operations. These findings shed new light on how SA might decrease in bridge teams during platform supply operations. The findings from this study emphasize the need to assess and establish shipboard practices that support the bridge teams' SA needs in day-to-day operations. Provides insights into how shipboard practices that are relevant to planning, communication and the occurrence of distracting/interrupting factors are realized in bridge operations.Notes possible areas for improvement to enhance distributed SA in bridge operations.

  2. Structural analysis of the ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Sannazzaro, G.; Ioki, K.; Johnson, G.; Onozuka, M.; Utin, Y. [ITER Joint Work Site, Garching (Germany); Nelson, B. [Oak Ridge National Lab., TN (United States); Swanson, J. [USHT, Raytheon, Princeton (United States)

    1998-07-01

    The ITER Vacuum Vessel (VV) must withstand a large number of loading conditions including electromagnetic, seismic, operational and upset pressure, thermal and test loads. All of the loading conditions and load combinations have been categorized and classified to permit the allowable stress to be defined in accordance with the recommendations of the ASME code. The most severe loading conditions for the VV are the toroidal field coil fast discharge (TFCFD) and the load combination of seismic and electromagnetic loads due to a plasma vertical instability. The areas of high stress are the regions around the VV and the blanket supports, and the attachment of the ports to the main shell. In all of the loading conditions and load combinations the calculated stresses are below the allowable values. (authors)

  3. Seismic-load-induced human errors and countermeasures using computer graphics in plant-operator communication

    International Nuclear Information System (INIS)

    Hara, Fumio

    1988-01-01

    This paper remarks the importance of seismic load-induced human errors in plant operation by delineating the characteristics of the task performance of human beings under seismic loads. It focuses on man-machine communication via multidimensional data like that conventionally displayed on large panels in a plant control room. It demonstrates a countermeasure to human errors using a computer graphics technique that conveys the global state of the plant operation to operators through cartoon-like, colored graphs in the form of faces that, with different facial expressions, show the plant safety status. (orig.)

  4. Applying Multi-Class Support Vector Machines for performance assessment of shipping operations: The case of tanker vessels

    DEFF Research Database (Denmark)

    Pagoropoulos, Aris; Møller, Anders H.; McAloone, Tim C.

    2017-01-01

    of feature selection algorithms. Afterwards, a model based on Multi- Class Support Vector Machines (SVM) was constructed and the efficacy of the approach is shown through the application of a test set. The results demonstrate the importance and benefits of machine learning algorithms in driving energy....... Identifying the potential of behavioural savings can be challenging, due to the inherent difficulty in analysing the data and operationalizing energy efficiency within the dynamic operating environment of the vessels. This article proposes a supervised learning model for identifying the presence of energy...

  5. Development and operational experiences of an automated remote inspection system for interior of primary containment vessel of a BWR

    International Nuclear Information System (INIS)

    Ozaki, N.; Chikara, S.; Fumio, T.; Katsuhiro, M.; Katsutoshi, S.; Ken-Ichiro, S.; Masaaki, F.; Masayoshi, S.

    1983-01-01

    A prototype was developed for an automated remote inspection system featuring continuous monitoring of the working status of major components inside the primary containment vessel of a boiling water reactor. This inspection system consists of four units, or vehicles, which are towed by a trolley chain along a monorail; a complex coaxial cable for data transmission and for power supply; and an operator's console. A TV camera, microphone, thermometer, hygrometer, and ionization chamber are mounted on the various units. After several months' testing under high-ambient temperature, the system was installed in the Tokai-2 power station of Japan Atomic Power Company for in situ tests

  6. Intra-operative colloid administration increases the clearance of a post-operative fluid load

    DEFF Research Database (Denmark)

    Borup, Tine; Hahn, Robert; Holte, K

    2009-01-01

    using volume kinetics based on the plasma dilution alone. The pre-operative plasma clearance was compared with the post-operative plasma clearance and patients served as their own control. RESULTS: The urinary excretion averaged 350 ml for the pre-operative infusion and 612 ml post-operatively, which...

  7. An investigation into the RCCI engine operation under low load and its achievable operational range at different engine speeds

    International Nuclear Information System (INIS)

    Wang, Yifeng; Zhu, ZhongWen; Yao, Mingfa; Li, Tie; Zhang, Weijing; Zheng, Zunqing

    2016-01-01

    Highlights: • The response of allowable RCCI operating range to engine speed variation is studied. • The RCCI and diesel LTC engine operations at are compared at low engine load. • The potential of expanding RCCI operating range at low engine speed is explored. - Abstract: Reactivity controlled compression ignition (RCCI) is demonstrated as a promising combustion strategy to achieve high efficiency and clean combustion. However, less effort has been devoted to examine the achievable RCCI operational range over a wide range of engine speed. In addition, previous studies have found that superior EGR rate and high diesel/gasoline fuel ratio are required to ease the extension of the low-load operating range of RCCI regime. Even then, relatively high CO and HC (unburned hydrocarbon) emissions and the accompanying fuel con-sum ption penalty still remain a problem to be resolved. Therefore, in this work the potential of diesel-fueled LTC to achieve simultaneously low NOx and soot emissions while maintaining high thermal efficiency at low load (IMEP ≈0.23–0.26 MPa) is investigated and compared with the gasoline/diesel RCCI strategy. The results show that the diesel LTC operation can yield slightly higher soot and NOx emissions (soot: 0.002 g/kW h, NOx: 0.446 g/kW h), but CO and HC emissions as well as the fuel consumption are much lower than the RCCI strategy, implying the diesel LTC regime may be more suitable for low-load operations. In addition, the RCCI operational range at speeds ranging from 900 to 2500 r/min is determined, the results show that the maximum achievable load (IMEP) increases with an increase in speed, and a maximum IMEP of 1.2 MPa can be achieved at an engine speed of 2300 r/min. Ultra-low NOx and soot emissions (soot < 0.003 g/kW h, NOx < 0.4 g/kW h) can be achieved under the maximum loading conditions at each speed investigated. However, high levels of CO and HC emissions still remain a big problem to be solved. The lowest fuel consumption

  8. Experimental study and simulation of transformation induced plasticity, and multiphase behaviour of the 16MND5 vessel steel under aniso-thermal multiaxial loading

    International Nuclear Information System (INIS)

    Coret, M.

    2001-01-01

    This work deals with the aniso-thermal multiphase behaviour of the French vessel steel and more specially about the transformation plasticity in the cases of multiaxial non-proportional loadings paths. The first part of this report is devoted to the presentation of a high temperature tension-torsion experimental device enable of obtaining a large range of cooling rate. This experimental set-up is used to explore the transformation plasticity under proportional or non-proportional loading paths, during austenitic, bainitic and martensitic transformations. The results of the tests are compared to the Leblond's model. In the last part, we propose a two-scale behaviour model in which the type of each phase behaviour can be different. This meso-model is finally used to simulate two real tests on structures. (author) [fr

  9. Power Generation by Zinc Antimonide Thin Film under Various Load Resistances at its Critical Operating Temperature

    DEFF Research Database (Denmark)

    Mir Hosseini, Seyed Mojtaba; Rezaniakolaei, Alireza; Rosendahl, Lasse Aistrup

    slightly reduces during unload conditions, although it is expected that by eliminating load in each step, the initial amount of voltage exactly repeats. Similar behavior is observed for Seebeck coefficient distribution versus time of working particularly in lower load resistances. Based on variation...... thin films operating under different load resistances at around its critical operating temperature, 400 ᵒC. The thermoelement is subjected to constant hot side temperature and to room temperature at the cold junction in order to measure the thin film TEG’s sample performance. The nominal loads equal...... to 10, 15, 20, 25, 30, 35, 40, 45… 175, and also 200 Ohms were applied. The results show that the value of the Seebeck coefficient is 0.0002 [V/K] for the specimen, which is in agreement with quantities of other zinc antimonide bulks materials in literature. The results also show that the voltage...

  10. Homemade battery-operated multi-barreled muzzle-loading gun.

    Science.gov (United States)

    Ramiah, R; Thirunavukkarasu, G

    2003-11-01

    In a recent shootout by a terrorist group against a law enforcement agency, some unusual firearms were seized. On examination, these firearms were found to be homemade, battery-operated, multi-barreled muzzle-loading guns, analogous to a repeater. Reference to battery-operated firearms is rather scanty in the literature. Hence, the unique design features, electrical circuit, and the operation system of these unusual guns are described.

  11. The effects of load-sensitive behavior on the operability margins of motor-operated gate valves

    International Nuclear Information System (INIS)

    Steele, R. Jr.; Russell, M.J.; DeWall, K.G.; Watkins, J.C.

    1993-01-01

    Testing of motor-operated gate valves at various loads has produced a phenomenon we call load-sensitive behavior. This phenomenon has a significant effect on the accuracy of the methods used (and proposed) in the nuclear industry for determining that these valves can perform their design basis function. A valve subjected to tests with low flow and pressure loadings may achieve a stem thrust (at seating) analytically determined to be adequate for design basis flows and pressures, but this is no guarantee that the valve will achieve the same stem thrust when actually subjected to those design basis loads. This is because the friction at the interface between the stem and the stem nut is higher in tests with higher flow and pressure loadings, and this loss to friction is outside the control of the motor-operator's torque switch. This paper identifies a tentative method for determining, a stable, useful value for the stem/stem-nut coefficient of friction, one that can possibly be extrapolated and used in calculations to accurately estimate the design basis thrust requirements of these valves

  12. A Bankruptcy Problem Approach to Load-shedding in Multiagent-based Microgrid Operation

    Directory of Open Access Journals (Sweden)

    Yujin Lim

    2010-09-01

    Full Text Available A microgrid is composed of distributed power generation systems (DGs, distributed energy storage devices (DSs, and loads. To maintain a specific frequency in the islanded mode as an important requirement,  the control of DGs’ output and charge action of DSs are used in supply surplus conditions and load-shedding and discharge action of DSs are used in supply shortage conditions. Recently, multiagent systems for autonomous microgrid operation have been studied. Especially, load-shedding, which is intentional reduction of electricity use, is a critical problem in islanded microgrid operation based on the multiagent system. Therefore, effective schemes for load-shedding are required. Meanwhile, the bankruptcy problem deals with dividing short resources among multiple agents. In order to solve the bankruptcy problem, division rules, such as the constrained equal awards rule (CEA, the constrained equal losses rule (CEL, and the random arrival rule (RA, have been used. In this paper, we approach load-shedding as a bankruptcy problem. We compare load-shedding results by above-mentioned rules in islanded microgrid operation based on wireless sensor network (WSN as the communication link for an agent’s interactions.

  13. A bankruptcy problem approach to load-shedding in multiagent-based microgrid operation.

    Science.gov (United States)

    Kim, Hak-Man; Kinoshita, Tetsuo; Lim, Yujin; Kim, Tai-Hoon

    2010-01-01

    A microgrid is composed of distributed power generation systems (DGs), distributed energy storage devices (DSs), and loads. To maintain a specific frequency in the islanded mode as an important requirement, the control of DGs' output and charge action of DSs are used in supply surplus conditions and load-shedding and discharge action of DSs are used in supply shortage conditions. Recently, multiagent systems for autonomous microgrid operation have been studied. Especially, load-shedding, which is intentional reduction of electricity use, is a critical problem in islanded microgrid operation based on the multiagent system. Therefore, effective schemes for load-shedding are required. Meanwhile, the bankruptcy problem deals with dividing short resources among multiple agents. In order to solve the bankruptcy problem, division rules, such as the constrained equal awards rule (CEA), the constrained equal losses rule (CEL), and the random arrival rule (RA), have been used. In this paper, we approach load-shedding as a bankruptcy problem. We compare load-shedding results by above-mentioned rules in islanded microgrid operation based on wireless sensor network (WSN) as the communication link for an agent's interactions.

  14. Automatic Control of Reactor Temperature and Power Distribution for a Daily Load following Operation

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Keuk Jong; Kim, Han Gon [Korea Hydro and Nuclear Power Institute, Daejeon (Korea, Republic of)

    2010-10-15

    An automatic control method of reactor power and power distribution was developed for a daily load following operation of APR1400. This method used a model predictive control (MPC) methodology having second-order plant data. And it utilized a reactor power ratio and axial shape index as control variables. However, the reactor regulating system of APR1400 is operated by the difference between the average temperature of the reactor core and the reference temperature, which is proportional to the turbine load. Thus, this paper reports on the model predictive control methodology using fourth-order plant data and a reactor temperature instead of the reactor power shape. The purpose of this study is to develop a revised automatic controller and analyze the behavior of the nuclear reactor temperature (Tavg) and the axial shape index (ASI) using the MPC method during a daily load following operation

  15. Development of Fast-Running Simulation Methodology Using Neural Networks for Load Follow Operation

    International Nuclear Information System (INIS)

    Seong, Seung-Hwan; Park, Heui-Youn; Kim, Dong-Hoon; Suh, Yong-Suk; Hur, Seop; Koo, In-Soo; Lee, Un-Chul; Jang, Jin-Wook; Shin, Yong-Chul

    2002-01-01

    A new fast-running analytic model has been developed for analyzing the load follow operation. The new model was based on the neural network theory, which has the capability of modeling the input/output relationships of a nonlinear system. The new model is made up of two error back-propagation neural networks and procedures to calculate core parameters, such as the distributions and density of xenon in a quasi-steady-state core like load follow operation. One neural network is designed to retrieve the axial offset of power distribution, and the other is for reactivity corresponding to a given core condition. The training data sets for learning the neural networks in the new model are generated with a three-dimensional nodal code and, also, the measured data of the first-day test of load follow operation. Using the new model, the simulation results of the 5-day load follow test in a pressurized water reactor show a good agreement between the simulation data and the actual measured data. Required computing time for simulating a load follow operation is comparable to that of a fast-running lumped model. Moreover, the new model does not require additional engineering factors to compensate for the difference between the actual measurements and analysis results because the neural network has the inherent learning capability of neural networks to new situations

  16. Operation and Equivalent Loads of Wind Turbines in Large Wind Farms

    Science.gov (United States)

    Andersen, Soren Juhl; Sorensen, Jens Norkaer; Mikkelsen, Robert Flemming

    2017-11-01

    Wind farms continue to grow in size and as the technology matures, the design of wind farms move towards including dynamic effects besides merely annual power production estimates. The unsteady operation of wind turbines in large wind farms has been modelled with EllipSys3D(Michelsen, 1992, and Sørensen, 1995) for a number of different scenarios using a fully coupled large eddy simulations(LES) and aero-elastic framework. The turbines are represented in the flow fields using the actuator line method(Sørensen and Shen, 2002), where the aerodynamic forces and deflections are derived from an aero-elastic code, Flex5(Øye, 1996). The simulations constitute a database of full turbine operation in terms of both production and loads for various wind speeds, turbulence intensities, and turbine spacings. The operating conditions are examined in terms of averaged power production and thrust force, as well as 10min equivalent flapwise bending, yaw, and tilt moment loads. The analyses focus on how the performance and loads change throughout a given farm as well as comparing how various input parameters affect the operation and loads of the wind turbines during different scenarios. COMWIND(Grant 2104-09- 067216/DSF), Nordic Consortium on Optimization and Control of Wind Farms, Eurotech Greentech Wind project, Winds2Loads, and CCA LES. Ressources Granted on SNIC and JESS. The Vestas NM80 turbine has been used.

  17. Optimal control of load-following operations in a pressurized water reactor

    International Nuclear Information System (INIS)

    Zhao Fuyu; Zhou Dawei

    2000-01-01

    According to the optimal control theory, the problem of load-following operation in a pressurized water reactor is formulated as a nonlinear-quadratic optimal control problem. One-dimensional core model is adopted. A successful optimization algorithm DDPSR is proposed to solving the obtained problem. The research results show that the DDPSR can converge with a long time interval and needs very small iteration number and computing time, and the practical reactor can be fairly operated in an optimal load-following manner and axial offset satisfies the required value from beginning to end. Control characters of boron concentration are discussed specially

  18. Resin-based preparation of HTGR fuels: operation of an engineering-scale uranium loading system

    International Nuclear Information System (INIS)

    Haas, P.A.

    1977-10-01

    The fuel particles for recycle of 233 U to High-Temperature Gas-Cooled Reactors are prepared from uranium-loaded carboxylic acid ion exchange resins which are subsequently carbonized, converted, and refabricated. The development and operation of individual items of equipment and of an integrated system are described for the resin-loading part of the process. This engineering-scale system was full scale with respect to a hot demonstration facility, but was operated with natural uranium. The feed uranium, which consisted of uranyl nitrate solution containing excess nitric acid, was loaded by exchange with resin in the hydrogen form. In order to obtain high loadings, the uranyl nitrate must be acid deficient; therefore, nitric acid was extracted by a liquid organic amine which was regenerated to discharge a NaNO 3 or NH 4 NO 3 solution waste. Water was removed from the uranyl nitrate solution by an evaporator that yielded condensate containing less than 0.5 ppM of uranium. The uranium-loaded resin was washed with condensate and dried to a controlled water content via microwave heating. The loading process was controlled via in-line measurements of the pH and density of the uranyl nitrate. The demonstrated capacity was 1 kg of uranium per hour for either batch loading contractors or a continuous column as the resin loading contractor. Fifty-four batch loading runs were made without a single failure of the process outlined in the chemical flowsheet or any evidence of inability to control the conditions dictated by the flowsheet

  19. Offshore wind transport and installation vessel

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The initial objective of the project was to complete a feasibility study to determine the viability of an innovative transportation vessel to be deployed in the installation of offshore wind farms. This included the feasibility of providing a stable-working platform that can be used in harsh offshore environments. A study of current installation contractors and their installation equipment was used to provide a preliminary specification for the installation vessel. A typical barge was selected and a number of hydrodynamic analyses were carried out in order to establish it's on course and operational stability. The analysis proved the stability of the vessel during operation was critical and that in order to utilise the crane's full potential a stabilisation system must be employed. The main aim of the work to date was to establish whether it was feasible to use a stabilisation system on the installation vessel. The spud leg FEED study established that it was feasible to use spud legs to stabilise the vessel. In order to achieve the degree of stability required it is necessary to lift the vessel completely out of the water. This was not the original aim of the study but due to the external loads on the hull it was the only viable option. Lifting the vessel out of the water results in the legs and leg casings becoming very large. This has a number of consequences for the final design. Due to large loads on the legs spud cans must be used to avoid bottom penetration, the spud cans increase the draft of the vessel by 2m. The large loads require larger winches and more reeving to be used, this results in larger pumps and motors, all of which have to be housed. The stabilisation system has been proved to be feasible for a large installation vessel, the cost and physical size are however more excessive than first anticipated. (Author)

  20. Increasing the flexibility of base-load generating units in operation on fossil fuel

    Energy Technology Data Exchange (ETDEWEB)

    Girshfel' d, V Ya; Khanaev, V A; Volkova, E D; Gorelov, V A; Gershenkroi, M L

    1979-01-01

    Increasing the flexibility of base-load generating units operating on fossil fuel by modifying them is a necessary measure. The highest economic effect is attained with modification of gas- and oil-fired generating units in the Western United Power Systems of the European part of the SPSS. On the basis of available experience, 150- and 200-MW units can be extensively used to regulate the power in the European part of the SPSS through putting them into reserve for the hours of the load dip at night. The change under favorable conditions of 150- and 200-MW units operating on coal to a district-heating operating mode does not reduce the possibilities for flexible operation of these units because it is possible greatly to unload the turbines while the minimum load level of the pulverized fuel fired boiler is retained through transferring a part of the heat load to the desuperheater. It is necessary to accumulate and analyze experience with operation of generating units (especially of supercritical units) with regular shutdowns and starts of groups of units and to solve the problems of modification of generating units, with differentiation with respect to types of fuel and to the united power supply system.

  1. Research on Operation and Control Strategy of 600MW PWR in Load Follow

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Bing Yang; Cao, Xin Rong [Harbin Engineering University, Harbin (China); Li, Han Chen [China Nuclear Power Engineering Co., Beijing (China)

    2014-08-15

    600MW Pressurized Water Reactor (PWR) is designed to operate in Constant Axial Offset Control (CAOC) strategy with base load originally. By calculations over a typical load follow scenario '12-3-6-3 {sup (}100-50-100%FP) via the CASMO-4E and SIMULATE-3 package, values of core operating parameter have been examined. With the progress of the nuclear power industry, advanced reactors are considered to have a good performance in load follow, economy and flexibility. Under the premise of fuel loading and structural dimensions unchanged, two independent control rod groups M and AO are used in 600MW pressurized water reactor to provide fine control of both the core reactivity and axial power distribution, which is named ' Improved G strategy .' The influences of different control rod distributions, composition materials, and overlap steps had in power changes have been examined in a comparative study to choose the optimal one.Then we simulate a range of load follow scenarios of the redesigned 600MW core without adjusting soluble boron concentration in the begin, middle and end of first cycle. This paper additionally demonstrated the moderator temperature coefficient and shutdown margin values of the reactor in Improved G strategy to compare with the thermal safety design criteria. It's demonstrated that adequate adjustment of control rod groups enable the core to perform load follow through Improved G strategy in 80% of cycle and save a large volume of liquid effluent particularly toward the end of cycle.

  2. The LG-bank control concept: An improved method for PWR load-following operation

    International Nuclear Information System (INIS)

    Park, Won Seok; Christenson, J.M.

    1990-01-01

    In this paper the authors present the results of an investigation of a new pressurized water reactor load-following control concept that utilizes light gray (LG) banks in combination with a single high-worth bank. The investigation determined a control strategy and a set of nuclear design parameters for the control banks that permits unrestricted load-following operation over a wide power range at both beginning-of-cycle and end-of-cycle conditions. Advantages of the LG-bank control concept are that flexible load-following maneuvers can be performed without either making changes in the boron concentration or requiring the continuous insertion of a high-worth control bank. These features remove both of the disadvantages of current gray-bank load-following designs, which generally require the continuous insertion of a high-worth bank and in some cases also involve changes in the boron concentration

  3. Transient heat loads in current fusion experiments, extrapolation to ITER and consequences for its operation

    International Nuclear Information System (INIS)

    Loarte, A; Saibene, G; Sartori, R; Riccardo, V; Andrew, P; Paley, J; Fundamenski, W; Eich, T; Herrmann, A; Pautasso, G; Kirk, A; Counsell, G; Federici, G; Strohmayer, G; Whyte, D; Leonard, A; Pitts, R A; Landman, I; Bazylev, B; Pestchanyi, S

    2007-01-01

    New experimental results on transient loads during ELMs and disruptions in present divertor tokamaks are described and used to carry out a extrapolation to ITER reference conditions and to draw consequences for its operation. In particular, the achievement of low energy/convective type I edge localized modes (ELMs) in ITER-like plasma conditions seems the only way to obtain transient loads which may be compatible with an acceptable erosion lifetime of plasma facing components (PFCs) in ITER. Power loads during disruptions, on the contrary, seem to lead in most cases to an acceptable divertor lifetime because of the relatively small plasma thermal energy remaining at the thermal quench and the large broadening of the power flux footprint during this phase. These conclusions are reinforced by calculations of the expected erosion lifetime, under these load conditions, which take into account a realistic temporal dependence of the power fluxes on PFCs during ELMs and disruptions

  4. Response Load Extrapolation for Wind Turbines during Operation Based on Average Conditional Exceedance Rates

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Naess, Arvid; Saha, Nilanjan

    2011-01-01

    to cases where the Gumbel distribution is the appropriate asymptotic extreme value distribution. However, two extra parameters are introduced by which a more general and flexible class of extreme value distributions is obtained with the Gumbel distribution as a subclass. The general method is implemented...... within a hierarchical model where the variables that influence the loading are divided into ergodic variables and time-invariant non-ergodic variables. The presented method for statistical response load extrapolation was compared with the existing methods based on peak extrapolation for the blade out......The paper explores a recently developed method for statistical response load (load effect) extrapolation for application to extreme response of wind turbines during operation. The extrapolation method is based on average conditional exceedance rates and is in the present implementation restricted...

  5. ASSESSMENT OF THE POTENTIAL FOR HYDROGEN GENERATION DURING GROUTING OPERATIONS IN THE R AND P REACTOR VESSELS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2010-05-24

    The R- and P-reactor buildings were retired from service and are now being prepared for deactivation and decommissioning (D and D). D and D activities consist primarily of immobilizing contaminated components and structures in a grout-like formulation. Aluminum corrodes very rapidly when it comes in contact with the alkaline grout materials and as a result produces hydrogen gas. To address this potential deflagration/explosion hazard, the Materials Science and Technology Directorate (MS and T) of the Savannah River National Laboratory (SRNL) has been requested to review and evaluate existing experimental and analytical studies of this issue to determine if any process constraints on the chemistry of the fill material and the fill operation are necessary. Various options exist for the type of grout material that may be used for D and D of the reactor vessels. The grout formulation options include ceramicrete (pH 6-8), low pH portland cement + silica fume grout (pH 10.4), or Portland cement groupt (pH 12.5). The assessment concluded that either ceramicrete or the silica fume grout may be used to safely grout the P-reactor vessel. The risk of accumulation of a flammable mixture of hydrogen between the grout-air interface and the top of the reactor is very low. Portland cement grout, on the other hand, for the same range of process parameters does not provide a margin of safety against the accumulation of flammable gas in the reactor vessel during grouting operations in the P-reactor vessel. It is recommended that this grout not be utilized for this task. The R-reactor vessel cotnains significantly less aluminum based on current facility process knowledge, surface observations, and drawings. Therefore, a Portland cement grout may be considered for grouting operations as well as the other grout formulations. For example, if the grout fill rate is less than 1 inch/min and the grout temperature is maintained at 70 C or less, the risk of hydrogen accumulation during fill

  6. Ultrasonic Inspection of Cracks in Stud Bolts of Reactor Vessels in Nuclear Power Plants by Signal Processing of Differential Operation

    International Nuclear Information System (INIS)

    Choi, Sang Woo; Lee, Joon Hyun; Oh, Won Deok

    2005-01-01

    The stud bolt is one of crucial parts for safe operation of reactor vessels in nuclear power plants, Crack initiation and propagation were reported in stud bolts that arc used for closure of reactor vessel and head, Stud bolts are inspected by ultrasonic technique during overhaul periodically for the prevention of stud bolt failure which could induce radioactive leakage from nuclear reactor, In conventional ultrasonic testing for inspection of stud bolts, cracks are detected by using shadow effect It takes too much time to inspect stud bolts by using conventional ultrasonic technique. In addition, there were numerous spurious signals reflected from every oblique surfaces of thread, In this study, the signal processing technique for enhancing conventional ultrasonic technique was introduced for inspecting stud bolts. The signal processing technique provides removing spurious signal reflected from every oblique surfaces of thread and enhances detectability of defects. Detectability for small crack was enhanced by using this signal processing in ultrasonic inspection of stud bolts in Nuclear Power Plants

  7. Constrained model predictive control for load-following operation of APR reactors

    International Nuclear Information System (INIS)

    Kim, Jae Hwan; Lee, Sim Won; Kim, Ju Hyun; Na, Man Gyun; Yu, Keuk Jong; Kim, Han Gon

    2012-01-01

    The load-following operation of APR+ reactor is needed to control the power effectively using the control rods and to restrain the reactivity control from using the boric acid for flexibility of plant operation. Usually, the reason why the disproportion of axial flux distribution occurs during load-following operation is xenon-induced oscillation. The xenon has a very high absorption cross-section and makes the impact on the reactor delayed by the iodine precursor. The power maneuvering using automatically load-following operation has advantage in terms of safety and economic operation of the reactor, so the controller has to be designed efficiently. Therefore, an advanced control method that meets the conditions such as automatic control, flexibility, safety, and convenience is necessary to load-following operation of APR+ reactor. In this paper, the constrained model predictive control (MPC) method is applied to design APR reactor's automatic load-following controller for the integrated thermal power level and axial shape index (ASI) control. Some controllers use only the current tracking command, but MPC considers future commands in addition to the current tracking command. So, MPC can achieve better tracking performance than others. Furthermore, an MPC is to used in many industrial process control systems. The basic concept of the MPC is to solve an optimization problem for a finite future time interval at present time and to implement the first optimal control input as the current control input. The KISPAC-1D code, which models the APR+ nuclear power plants, is interfaced to the proposed controller to verify the tracking performance of the reactor power level and ASI. It is known that the proposed controller exhibits very fast tracking responses

  8. Determination of the wind power systems load to achieve operation in the maximum energy area

    Science.gov (United States)

    Chioncel, C. P.; Tirian, G. O.; Spunei, E.; Gillich, N.

    2018-01-01

    This paper analyses the operation of the wind turbine, WT, in the maximum power point, MPP, by linking the load of the Permanent Magnet Synchronous Generator, PMSG, with the wind speed value. The load control methods at wind power systems aiming an optimum performance in terms of energy are based on the fact that the energy captured by the wind turbine significantly depends on the mechanical angular speed of the wind turbine. The presented control method consists in determining the optimal mechanical angular speed, ωOPTIM, using an auxiliary low power wind turbine, WTAUX, operating without load, at maximum angular velocity, ωMAX. The method relies on the fact that the ratio ωOPTIM/ωMAX has a constant value for a given wind turbine and does not depend on the time variation of the wind speed values.

  9. Preliminary study of S-CO{sub 2} cycle control logic for part load operation

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Yoonhan; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2016-05-15

    The benefits of S-CO{sub 2} cycle are relatively high efficiency under the mild turbine inlet temperature region, simple layout configuration and small foot-print. In addition, the safety of the SFR system can be inherently enhanced as the violent sodium-water reaction can be substituted with the mild sodium-CO{sub 2} reaction. 75MWe S-CO{sub 2} recompression cycle with radial type turbomachineries and PCHE was designed. Under various part load conditions (30-100% thermal load), off-design performance of the designed system was assessed, and different control logics were first tested. It was identified that the inventory control strategy is the most efficient logic for the part load operation. In the system operation, the compressor surge condition is seriously considered and controlled to avoid the system damage.

  10. Fatigue status assessment for reactor pressure vessel based on actual operational transient

    International Nuclear Information System (INIS)

    Zhu Guangqiang; Liao Changbin; Dai Bing; Gui Chun

    2013-01-01

    Background: Fatigue is an important aging mechanism in RPV and it must be contained to aging management working range. Purpose: In order to ensure the safety operation of nuclear power plants, as extension of RPV service time, it is necessary to assess the fatigue damage caused by actual operation transient. Methods: Based on monitoring data of actual operation during the past eleven years, refer to design transient, the statistic analysis for types and occurrence times of actual transient is carried out, at the same time, every transients are combined as different operation cycles and the temperature field and stress field of typical components are analyzed by FEM. Results: Based on these information, fatigue analysis and assessment are finished, if later-actual transients are similar with the previous transients, the calculation result shows that the ratio between maximum of cumulative usage factors and design calculation value is 0.4967 the design transients is conservative. Conclusions: Fatigue status of RPV could be assessed and traced quickly through fatigue status assessment method in this paper based on actual operational transient and assessment result would be a good reference for RPV aging management. (authors)

  11. HANFORD DOUBLE SHELL TANK (DST) THERMAL & SEISMIC PROJECT SUMMARY OF COMBINED THERMAL & OPERATING LOADS

    Energy Technology Data Exchange (ETDEWEB)

    MACKEY, T.C.

    2006-03-17

    This report summarizes the results of the Double-Shell Tank Thermal and Operating Loads Analysis (TOLA) combined with the Seismic Analysis. This combined analysis provides a thorough, defensible, and documented analysis that will become a part of the overall analysis of record for the Hanford double-shell tanks (DSTs).

  12. The effect of dynamic operating conditions on nano-particle emissions from a light-duty diesel engine applicable to prime and auxiliary machines on marine vessels

    Directory of Open Access Journals (Sweden)

    Hyungmin Lee

    2012-12-01

    Full Text Available This study presents the nano-sized particle emission characteristics from a small turbocharged common rail diesel engine applicable to prime and auxiliary machines on marine vessels. The experiments were conducted under dynamic engine operating conditions, such as steady-state, cold start, and transient conditions. The particle number and size distributions were analyzed with a high resolution PM analyzer. The diesel oxidation catalyst (DOC had an insignificant effect on the reduction in particle number, but particle number emissions were drastically reduced by 3 to 4 orders of magnitude downstream of the diesel particulate filter (DPF at various steady conditions. Under high speed and load conditions, the particle filtering efficiency was decreased by the partial combustion of trapped particles inside the DPF because of the high exhaust temperature caused by the increased particle number concentration. Retarded fuel injection timing and higher EGR rates led to increased particle number emissions. As the temperature inside the DPF increased from 25 °C to 300 °C, the peak particle number level was reduced by 70% compared to cold start conditions. High levels of nucleation mode particle generation were found in the deceleration phases during the transient tests.

  13. Boundary element analysis of stress due to thermal shock loading or reactor pressure vessel nozzle; Napetostna analiza pri nestacionarni termicni obremenitvi cevnega prikljucka reaktorske tlacne posode z metodo robnih elementov

    Energy Technology Data Exchange (ETDEWEB)

    Kramberger, J; Potrc, I [Tehniska fakulteta, Maribor (Yugoslavia)

    1989-07-01

    Apart from being exposed to the primary loading of internal pressure and steady temperature field, the reactor pressure vessel is also subject to various thermal transients (thermal shocks). Theoretical and experimental stress analyses show that severe material stresses occur in the nozzle area of the pressure vessel which may lead to defects (cracks). It has been our aim to evaluate these stresses by the use of the Boundary Element method. (author)

  14. Radio-activity measurements inside the pressure-vessel of the reactor G 3 after 4 years operation

    International Nuclear Information System (INIS)

    Chassany, J.Ph.; Guillermin, P.; Delmar, J.

    1965-01-01

    At the end of the piping coming into the vessel, the dose rate reached 75 mR/hr and 100 mR/hr near the deflector. On the other side of this deflector it was still 100 mR/hr and then increased rapidly to over 1 R/hr at 1 metre distance from the starting-up chambers. On the sides, the flux tended to decrease (80 mR/hr) and was 2 R/hr at a height of 3 metres. This dose rate could certainly have been decreased by discharging the peripheral zone of the reactor. Consequently it should be possible to intervene if necessary, on condition that great care is taken to avoid contamination and that the total dose is followed as precisely as possible during the operations. (authors) [fr

  15. Models and Algorithms for Container Vessel Stowage Optimization

    DEFF Research Database (Denmark)

    Delgado-Ortegon, Alberto

    .g., selection of vessels to buy that satisfy specific demands), through to operational decisions (e.g., selection of containers that optimize revenue, and stowing those containers into a vessel). This thesis addresses the question of whether it is possible to formulate stowage optimization models...... container of those to be loaded in a port should be placed in a vessel, i.e., to generate stowage plans. This thesis explores two different approaches to solve this problem, both follow a 2-phase decomposition that assigns containers to vessel sections in the first phase, i.e., master planning...

  16. Operation and control of a hybrid microgrid containing unbalanced and nonlinear loads

    Energy Technology Data Exchange (ETDEWEB)

    Shahnia, Farhad; Majumder, Ritwik; Ghosh, Arindam; Ledwich, Gerard; Zare, Firuz [School of Engineering, Queensland University of Technology, 2 George Street, Brisbane, Queensland 4001 (Australia)

    2010-08-15

    This paper shows how the power quality can be improved in a microgrid that is supplying a nonlinear and unbalanced load. The microgrid contains a hybrid combination of inertial and converter interfaced distributed generation units where a decentralized power sharing algorithm is used to control its power management. One of the distributed generators in the microgrid is used as a power quality compensator for the unbalanced and harmonic load. The current reference generation for power quality improvement takes into account the active and reactive power to be supplied by the micro-source which is connected to the compensator. Depending on the power requirement of the nonlinear load, the proposed control scheme can change modes of operation without any external communication interfaces. The compensator can operate in two modes depending on the entire power demand of the unbalanced nonlinear load. The proposed control scheme can even compensate system unbalance caused by the single-phase micro-sources and load changes. The efficacy of the proposed power quality improvement control and method in such a microgrid is validated through extensive simulation studies using PSCAD/EMTDC software with detailed dynamic models of the micro-sources and power electronic converters. (author)

  17. Classifying Vessels Operating in the South China Sea by Origin with the Automatic Identification System

    Science.gov (United States)

    2018-03-01

    p. 5) means to track voyage and safety related information in real time. Over time, massive amounts of information related to maritime operations... safety related messages from land based stations, navigation aids, and search and rescue (SAR) crews. All AIS messages are intended to encourage open...United States is the South China Sea. Eight countries, China, Taiwan, the Philippines, Brunei, Indonesia, Malaysia , Singapore, and Vietnam

  18. An application of low leakage loading pattern to reduce fast neutrons. Fluence on WWER-440 reactor pressure vessel in Kozloduy NPP

    International Nuclear Information System (INIS)

    Haralampieva, Tz.; Antonov, A.; Monev, M.

    2001-01-01

    The neutron exposure of a reactor pressure vessel (RPV) is one of the key factors that have to be quantified and assess reliably to provide plant life assurance and for an extension to operational life. This paper summarizes the principal methods that are used in core design optimisation for WWER-440 reactors in NPP-Kozloduy in order to reduce flux of fast neutrons at the RPV. Results of fast neutron fluence changes during the all last cycles of units 1-4 with WWER-440 reactors are considered (Authors)

  19. Automatic Power Control for Daily Load-following Operation using Model Predictive Control Method

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Keuk Jong; Kim, Han Gon [KH, Daejeon (Korea, Republic of)

    2009-10-15

    Under the circumstances that nuclear power occupies more than 50%, nuclear power plants are required to be operated on load-following operation in order to make the effective management of electric grid system and enhanced responsiveness to rapid changes in power demand. Conventional reactors such as the OPR1000 and APR1400 have a regulating system that controls the average temperature of the reactor core relation to the reference temperature. This conventional method has the advantages of proven technology and ease of implementation. However, this method is unsuitable for controlling the axial power shape, particularly the load following operation. Accordingly, this paper reports on the development of a model predictive control method which is able to control the reactor power and the axial shape index. The purpose of this study is to analyze the behavior of nuclear reactor power and the axial power shape by using a model predictive control method when the power is increased and decreased for a daily load following operation. The study confirms that deviations in the axial shape index (ASI) are within the operating limit.

  20. Advances in the Assessment of Wind Turbine Operating Extreme Loads via More Efficient Calculation Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Graf, Peter; Damiani, Rick R.; Dykes, Katherine; Jonkman, Jason M.

    2017-01-09

    A new adaptive stratified importance sampling (ASIS) method is proposed as an alternative approach for the calculation of the 50 year extreme load under operational conditions, as in design load case 1.1 of the the International Electrotechnical Commission design standard. ASIS combines elements of the binning and extrapolation technique, currently described by the standard, and of the importance sampling (IS) method to estimate load probability of exceedances (POEs). Whereas a Monte Carlo (MC) approach would lead to the sought level of POE with a daunting number of simulations, IS-based techniques are promising as they target the sampling of the input parameters on the parts of the distributions that are most responsible for the extreme loads, thus reducing the number of runs required. We compared the various methods on select load channels as output from FAST, an aero-hydro-servo-elastic tool for the design and analysis of wind turbines developed by the National Renewable Energy Laboratory (NREL). Our newly devised method, although still in its infancy in terms of tuning of the subparameters, is comparable to the others in terms of load estimation and its variance versus computational cost, and offers great promise going forward due to the incorporation of adaptivity into the already powerful importance sampling concept.

  1. Assessment of Gearbox Operational Loads and Reliability under High Mean Wind Speeds

    DEFF Research Database (Denmark)

    Dabrowski, Dariusz; Natarajan, Anand

    2015-01-01

    wind turbine that operates in storm conditions with mean wind speeds less than 30 m/s is presented. In the study, normal shut-downs of a wind turbine in storm conditions were investigated. The analysis were conducted for two storm control strategies and different wind conditions from an extreme...... operating gust, normal turbulence model and extreme turbulence model. In the paper, loads in the planetary gear are quantified as well as the torsional moments in the main shaft. On the basis of simulation results the annual probability of failure of the gearbox in a wind turbine with soft storm controller...... is calculated, and compared with the one had the gearbox working in a wind turbine operating with hard storm controller. In the study, it was found that normal shut-downs do not have a significant influence on the ultimate loads in the gearbox, since they are related mostly to the gusts occurring during...

  2. The NINO [No Inspector, No Operator system] cask-loading safeguards system

    International Nuclear Information System (INIS)

    Fiarman, S.

    1987-01-01

    It is, in general difficult to determine by means of camera-surveillance techniques what is loaded into spent-fuel casks being prepared for shipment from light-water reactors to other reactors, reprocessing facilities, or long-term storage. Furthermore, the expected high frequency of cask loadings in the coming years would place too great a burden on the IAEA and Euratom inspectorates if each had to be observed by an inspector. For the case of shipment to other reactors and reprocessing facilities, the casks are soon opened and, in principle, their contents could be ascertained by direct inspection. In the case of long-term-storage facilities, the casks would stay sealed for years, thereby requiring the IAEA to know positively how many spent-fuel assemblies were loaded at the reactor and to have a continuity of knowledge of the cask's contents. It has been proposed instead that the facility operator place the cask seal on the cask within the field of view of a surveillance system linked to the cask seal. This solution, however, may not provide enough credibility for acceptance by the safeguards community. This paper presents an alternative to both inspector presence at cask loading and operator assistance in applying seals; this alternative is called the No Inspector, No Operator system (NINO)

  3. Subjective and objective symptoms of psychical load in nuclear power plant operators in connection with shift operation

    International Nuclear Information System (INIS)

    Kozeny, J.; Prochazkova, Z.

    1992-01-01

    A group of 56 operators (mean age=34.6 years, S.D. 3.4 year, range=30-40 years; university graduates of technical direction) in a nuclear power plant was followed during the morning, afternoon and night shift from the standpoint of subjective symptoms (an evaluation scale assessed at the beginning, in the middle and at the end of the shift) and objective symptoms (critical flicker frequency determined at the same time) of the psychical load. No significant differences were found by multivariation analysis between subjective perception of the work load and its objective reflection. The night shift, where the load lies particularly in the monotony of stimuli, appears to exert a higher psychical load aimed at maintaining mental activity when compared with the afternoon and morning shift. In contrast to subjective assessment of the psychical condition where the data fluctuated during the whole shift, the psychical activity reflected in the objective data, decreased until the middle of the shift when stabilization occurred. (author) 1 tab., 8 refs

  4. A Novel Control Strategy for Autonomous Operation of Isolated Microgrid with Prioritized Loads

    Science.gov (United States)

    Kumar, R. Hari; Ushakumari, S.

    2018-05-01

    Maintenance of power balance between generation and demand is one of the most critical requirements for the stable operation of a power system network. To mitigate the power imbalance during the occurrence of any disturbance in the system, fast acting algorithms are inevitable. This paper proposes a novel algorithm for load shedding and network reconfiguration in an isolated microgrid with prioritized loads and multiple islands, which will help to quickly restore the system in the event of a fault. The performance of the proposed algorithm is enhanced using genetic algorithm and its effectiveness is illustrated with simulation results on modified Consortium for Electric Reliability Technology Solutions (CERTS) microgrid.

  5. Assessment of Gearbox Operational Loads and Reliability under High Mean Wind Speeds

    OpenAIRE

    Dabrowski, Dariusz; Natarajan, Anand

    2015-01-01

    This paper investigates the dynamic loads occurring in the drivetrain of wind turbines with a focus on offshore applications. Herein a model of the gearbox of the 5 MW wind turbine is presented. The model is developed in a multi-body framework using commercial software MSC ADAMS. Validation of the model was based on the experimental data provided by NREL for 750 kW prototype gearbox. Failures of gearboxes caused by high dynamic loads have a significant influence on the cost of operation of wi...

  6. Fatigue Load Modeling and Control for Wind Turbines based on Hysteresis Operators

    DEFF Research Database (Denmark)

    Barradas Berglind, Jose de Jesus; Wisniewski, Rafal; Soltani, Mohsen

    2015-01-01

    method based on hysteresis operators, which can be used in control loops. Furthermore, we propose a model predictive control (MPC) strategy that incorporates the online fatigue estimation through the objective function, where the ultimate goal in mind is to reduce the fatigue load of the wind turbine......The focus of this work is on fatigue load modeling and controller design for the wind turbine level. The main purpose is to include a model of the damage effects caused by the fatigue of the wind turbine components in the controller design process. This paper addresses an online fatigue estimation...

  7. Apparatuses and methods of determining if a person operating equipment is experiencing an elevated cognitive load

    Science.gov (United States)

    Watkins, Michael L.; Keller, Paul Edwin; Amaya, Ivan A.

    2015-06-16

    A method of, and apparatus for, determining if a person operating equipment is experiencing an elevated cognitive load, wherein the person's use of a device at a first time is monitored so as to set a baseline signature. Then, at a later time, the person's use of the device is monitored to determine the person's performance at the second time, as represented by a performance signature. This performance signature can then be compared against the baseline signature to predict whether the person is experiencing an elevated cognitive load.

  8. LOFT reactor vessel 290/sup 0/ downcomer stalk instrument penetration flange stress analysis

    Energy Technology Data Exchange (ETDEWEB)

    Finicle, D.P.

    1978-06-06

    The LOFT Reactor Vessel 290/sup 0/ Downcomer Stalk Instrument Penetration Flange Stress Analysis has been completed using normal operational and blowdown loading. A linear elastic analysis was completed using simplified hand analysis techniques. The analysis was in accordance with the 1977 ASME Boiler and Pressure Vessel Code, Section III, for a Class 1 component. Loading included internal pressure, bolt preload, and thermal gradients due to normal operating and blowdown.

  9. Recent development for improving the PWR flexibility to load follow and frequency control operation

    International Nuclear Information System (INIS)

    Dubourg, M.

    1983-01-01

    The increasing production of nuclear electricity generated by PWR in the French network will modify the operating conditions of these plants for adjusting the electricity generation to the consumption. For assessing the adequacy of main components, FRAMATOME, in conjunction with Electricite de France and the Commissariat a l'Energie Atomique has undertaken a large R and D effort and initiated significant design changes for sustaining the new operating modes including. Daily load follow and frequency remote dispatch operation (+- 5% random fluctuation load around a present value). These new operating conditions generate additional mechanical and thermal sollicitations due to the frequent motion of control rod banks, consisting of: a) Mechanical fatigue cycling and wear at the level of control rod drive mechanisms (CRDM), control rods and guides tubes. b) Wear and thermal fatigue cycling at the level of fuel assemblies. This paper will present the various aspects of this program including: Identification of the most critical areas of components; Basic research in laboratories for resolving wear problems in PWR environment; Improvement of local hydraulics for reducing loads; Endurance testing of full scale components on testing facilities. (orig./GL)

  10. Operational transparency: an advanced safeguards strategy for future on-load refuelled reactors

    International Nuclear Information System (INIS)

    Whitlock, J.J.; Trask, D.

    2012-01-01

    The IAEA's system for tracking fuel movement in an on-load refuelled heavy-water reactor is robust, but an opportunity remains to exploit the wealth of data streaming from the reactor vault during operation and provide real-time, third-party monitoring of reactor status and history. This concept of Operational Transparency would require that large amounts of operational data be reduced in near-real time to a small subset of high-level information. Operational Transparency would enhance the IAEA's ability to monitor the state of the core to an unprecedented level. This paper provides an overview of the novel concept of Operational Transparency in heavy water reactors, using potential application to CANDU reactors as an example, and explores some of the technical challenges that will need to be solved for efficient implementation. (author)

  11. A Remote-operated System to Map Radiation Dose in the Fukushima Daiichi Primary Containment Vessel

    Science.gov (United States)

    Nancekievill, M.; Jones, A. R.; Joyce, M. J.; Lennox, B.; Watson, S.; Katakura, J.; Okumura, K.; Kamada, S.; Katoh, M.; Nishimura, K.

    2018-01-01

    This paper describes the development of a submersible system based on a remote-operated vehicle coupled with radiation detectors to map the interior of the reactors at the Fukushima Daiichi nuclear power station. It has the aim oflocating fuel debris. The AVEXIS submersible vehicle used in this study has been designed as a low-cost, potentially disposable, inspection platform that is the smallest of its class and is capable of being deployed through a 150 mm diameter access pipe. To map the gamma-ray environment, a cerium bromide scintillator detector with a small form factor has been incorporated into the AVEXIS to identify radioactive isotopes via gamma-ray spectroscopy. This provides the combined system with the potential to map gamma-ray spectra and particle locations throughout submerged, contaminated facilities, such as Units 1, 2 and 3 of the Fukushima Daiichi nuclear power plant. The hypothesis of this research is to determine the sensitivity of the combined system in a submerged environment that replicates the combination of gamma radiation and water submersion but at lower dose rates.

  12. Operation window and part-load performance study of a syngas fired gas turbine

    International Nuclear Information System (INIS)

    He, Fen; Li, Zheng; Liu, Pei; Ma, Linwei; Pistikopoulos, Efstratios N.

    2012-01-01

    Integrated coal gasification combined cycle (IGCC) provides a great opportunity for clean utilization of coal while maintaining the advantage of high energy efficiency brought by gas turbines. A challenging problem arising from the integration of an existing gas turbine to an IGCC system is the performance change of the gas turbine due to the shift of fuel from natural gas to synthesis gas, or syngas, mainly consisting of carbon monoxide and hydrogen. Besides the change of base-load performance, which has been extensively studied, the change of part-load performance is also of great significance for the operation of a gas turbine and an IGCC plant. In this paper, a detailed mathematical model of a syngas fired gas turbine is developed to study its part-load performance. A baseline is firstly established using the part-load performance of a natural gas fired gas turbine, then the part-load performance of the gas turbine running with different compositions of syngas is investigated and compared with the baseline. Particularly, the impacts of the variable inlet guide vane, the degree of fuel dilution, and the degree of air bleed are investigated. Results indicate that insufficient cooling of turbine blades and a reduced compressor surge margin are the major factors that constrain the part-load performance of a syngas fired gas turbine. Results also show that air bleed from the compressor can greatly improve the working condition of a syngas fired gas turbine, especially for those fired with low lower heating value syngas. The regulating strategy of a syngas fired gas turbine should also be adjusted in accordance to the changes of part-load performance, and a reduced scope of constant TAT (turbine exhaust temperature) control mode is required.

  13. Load following operation of nuclear power plants for meeting power system requirements

    International Nuclear Information System (INIS)

    Isoda, Hachiro

    1987-01-01

    This paper describes a calculating program on the availability factors of nuclear, thermal and pumed storage hydro power stations and some calculated results for typical three load factors, 55 %, 60 % and 71 %, are provided when the share of the nuclea power station in the generation facilities is increased. The load following requirement of the nuclear power station is also provided. Load following requirement: If there is a 10 % pumped storage hydro power station, the nuclear power station enables to be operated with its rated output up to 30 % - 35 % of its share. Its daily load following operation for 40 % and 50 % nuclear power station needs every weekend and every day respectively. Availability factor: The availability factor of the nuclear power station manages to get 80 % (maximum availability factor of the nuclear power station in this study) up to 30 % share of it with 10 % pumpued storage hydro power station. When the nuclear power station shares 40 % and 50 %, its availability factor decreases down 1 % and 5 % respectively. (author)

  14. The need to pressure test prestressed concrete reactor vessels

    International Nuclear Information System (INIS)

    Forgie, J.H.; Holland, J.A.

    1983-01-01

    In the period when PCRV were relatively unproven, proof pressure testing provided a useful demonstration of vessel integritiy and a confirmation of model testing and of analysis. No failures have occurred during concrete vessel tests in the UK or in the subsequent operational life of the vessels and much has been learned of their behaviour in service. The paper examines the advantages and disadvantages of proof testing PCRV in the light of the above increased knowledge of vessel performance. The paper draws attention to certain hypothetical loading cases that could be more onerous than the proof test and suggests that pressure testing could itself cause unnecessarily high loading to parts of the vessel. Always recognising the safety considerations and demonstrations of such are of prime importance, the authors suggest that a lower pressure level could be adopted without loss of original intent. In addition some ground rules are suggested as to cases where proof testing could be omitted. (orig./HP)

  15. Keep fatigue usage low for LTO. Benefits of load monitoring and related fatigue evaluations for long term operation

    International Nuclear Information System (INIS)

    Rothenhoefer, H.; Koenig, G.

    2012-01-01

    Design fatigue calculations normally cover a service life of 40 years. Based on design transients with a specified number of cycles the evaluations have to prove that the fatigue usage after 40 years will stay below 1. In 40+ years of operation real loads can differ much from design loads so that premature ageing can occur. For long term operation, monitoring of real loads and detailed fatigue analysis for selected locations can be used to optimize operational modes in order to reduce the loads causing fatigue. As a result fatigue usage can be kept below 1 even for 60+ years. (author)

  16. A Study on Load Following Operation Strategy to Minimize Boric-acid Adjustment

    International Nuclear Information System (INIS)

    Yoo, Jae Woon

    1997-02-01

    Applicability of the MSHIM control strategy, which has been developed by Westinghouse and characterized by elimination of the adjustment to the boron concentration during load maneuvering, to 1300MWe KNGR Cycle-1 is examined by simulation based on one-dimensional transient analyses code, ONED94, under the conditions of relatively large xenon worth and high amplitude of xenon oscillation. CASMO-3/MASTER code system is used to generate the ONED94 model. A processing code, which is referred to as MAS2ONED, is also developed to transform the MASTER calculation results to ONED94 cross section library. The three types of power maneuvering, daily maneuvering, extended weekend load follow, and spinning reserve capacity are simulated to evaluate the capability of the selected load follow technology, by using ONED94 code. By showing that the calculated total peaking factor is maintained below safety limit, it is proved that load follow operation without boron adjustment is feasible with simple control rod motion only. It is expected that the results of this study, such as control rod parameters could give a contribution to the development of load following technology in our country. The developed process code could be utilized in the another simulation of power maneuver in the future

  17. Mechanical Properties of a Unidirectional Basalt-Fiber-Reinforced Plastic Under a Loading Simulating Operation Conditions

    Science.gov (United States)

    Lobanov, D. S.; Slovikov, S. V.

    2017-01-01

    The results of experimental investigations of unidirectional composites based on basalt fibers and different marks of epoxy resins are presented. Uniaxial tensile tests were carried out using a specimen fixation technique simulating the operation conditions of structures. The mechanical properties of the basalt-fiber-reinforced plastics (BFRPs) were determined. The diagrams of loading and deformation of BFRP specimens were obtain. The formulations of the composites with the highest mechanical properties were revealed.

  18. Switch Panel wear loading - a parametric study regarding governing train operational factors

    Science.gov (United States)

    Hiensch, E. J. M.; Burgelman, N.

    2017-09-01

    The acting forces and resulting material degradation at the running surfaces of wheels and rail are determined by vehicle, track, interface and operational characteristics. To effectively manage the experienced wear, plastic deformation and crack development at wheels and rail, the interaction between vehicle and track demands a system approach both in maintenance and in design. This requires insight into the impact of train operational parameters on rail- and wheel degradation, in particular at switches and crossings due to the complex dynamic behaviour of a railway vehicle at a turnout. A parametric study was carried out by means of vehicle-track simulations within the VAMPIRE® multibody simulation software, performing a sensitivity analysis regarding operational factors and their impact on expected switch panel wear loading. Additionally, theoretical concepts were cross-checked with operational practices by means of a case study in response to a dramatic change in lateral rail wear development at specific switches in Dutch track. Data from train operation, track maintenance and track inspection were analysed, providing further insight into the operational dependencies. From the simulations performed in this study, it was found that switch rail lateral wear loading at the diverging route of a 1:9 type turnout is significantly influenced by the level of wheel-rail friction and to a lesser extent by the direction of travel (facing or trailing). The influence of other investigated parameters, being vehicle speed, traction, gauge widening and track layout is found to be small. Findings from the case study further confirm the simulation outcome. This research clearly demonstrates the contribution flange lubrication can have in preventing abnormal lateral wear at locations where the wheel-rail interface is heavily loaded.

  19. Application of load follow operation to equilibrium cycle of OPR1000

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyeongju; Choe, Jiwon; Lee, Deokjung [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2012-10-15

    All nuclear power plants in Korea are operated at a base load, that is 100% rated power, and do not rely largely on power tracking control except for startup, shutdown, and some minor problem occurrences. However, if the electricity from nuclear power plants exceeds 50% of total electricity generation according to national energy plan, load follow operation is necessary to efficiently use the electrical energy. But it is very difficult to control the axial power distribution and reactor core reactivity at the same time as needed because of variations in nuclear system parameters. In 1990s, an advanced reactor control algorithm, Mode-K, was developed which uses regulation banks, boron control, and a heavy-worth bank (H-bank). The regulation banks and boron control are used for core reactivity control and the H-bank is used for the control of axial power shape. In this study, reactor core simulations with HELIOS/MASTER code system using Mode-K strategy are applied to the daily load follow operation in equilibrium cycle of OPR1000.

  20. Numerical Simulation and Validation of a High Head Model Francis Turbine at Part Load Operating Condition

    Science.gov (United States)

    Goyal, Rahul; Trivedi, Chirag; Kumar Gandhi, Bhupendra; Cervantes, Michel J.

    2017-07-01

    Hydraulic turbines are operated over an extended operating range to meet the real time electricity demand. Turbines operated at part load have flow parameters not matching the designed ones. This results in unstable flow conditions in the runner and draft tube developing low frequency and high amplitude pressure pulsations. The unsteady pressure pulsations affect the dynamic stability of the turbine and cause additional fatigue. The work presented in this paper discusses the flow field investigation of a high head model Francis turbine at part load: 50% of the rated load. Numerical simulation of the complete turbine has been performed. Unsteady pressure pulsations in the vaneless space, runner, and draft tube are investigated and validated with available experimental data. Detailed analysis of the rotor stator interaction and draft tube flow field are performed and discussed. The analysis shows the presence of a rotating vortex rope in the draft tube at the frequency of 0.3 times of the runner rotational frequency. The frequency of the vortex rope precession, which causes severe fluctuations and vibrations in the draft tube, is predicted within 3.9% of the experimental measured value. The vortex rope results pressure pulsations propagating in the system whose frequency is also perceive in the runner and upstream the runner.

  1. Multiple shell pressure vessel

    International Nuclear Information System (INIS)

    Wedellsborg, B.W.

    1988-01-01

    A method is described of fabricating a pressure vessel comprising the steps of: attaching a first inner pressure vessel having means defining inlet and outlet openings to a top flange, placing a second inner pressure vessel, having means defining inlet and outlet opening, concentric with and spaced about the first inner pressure vessel and attaching the second inner pressure vessel to the top flange, placing an outer pressure vessel, having inlet and outlet openings, concentric with and spaced apart about the second inner pressure vessel and attaching the outer pressure vessel to the top flange, attaching a generally cylindrical inner inlet conduit and a generally cylindrical inner outlet conduit respectively to the inlet and outlet openings in the first inner pressure vessel, attaching a generally cylindrical outer inlet conduit and a generally cylindrical outer outlet conduit respectively to the inlet and outlet opening in the second inner pressure vessel, heating the assembled pressure vessel to a temperature above the melting point of a material selected from the group, lead, tin, antimony, bismuth, potassium, sodium, boron and mixtures thereof, filling the space between the first inner pressure vessel and the second inner pressure vessel with material selected from the group, filling the space between the second inner pressure vessel and the outer pressure vessel with material selected from the group, and pressurizing the material filling the spaces between the pressure vessels to a predetermined pressure, the step comprising: pressurizing the spaces to a pressure whereby the wall of the first inner pressure vessel is maintained in compression during steady state operation of the pressure vessel

  2. Operational method for demonstrating fuel loading integrity in a reactor having accessible 235U fuel

    International Nuclear Information System (INIS)

    Ward, D.R.

    1979-07-01

    The Health Physics Research Reactor is a small pulse reactor at the Oak Ridge National Laboratory. It is desirable for the operator to be able to demonstrate on a routine basis that all the fuel pieces are present in the reactor core. Accordingly, a technique has been devised wherein the control rod readings are recorded with the reactor at delayed critical and corrections are made to compensate for the effects of variations in reactor height above the floor, reactor power, core temperature, and the presence of any massive neutron reflectors. The operator then compares these readings with the values expected based on previous operating experience. If this routine operational check suggests that the core fuel loading might be deficient, a more rigorous follow-up may be made

  3. Structural failure analysis of reactor vessels due to molten core debris

    International Nuclear Information System (INIS)

    Pfeiffer, P.A.

    1993-01-01

    Maintaining structural integrity of the reactor vessel during a postulated core melt accident is an important safety consideration in the design of the vessel. This paper addresses the failure predictions of the vessel due to thermal and pressure loadings from the molten core debris depositing on the lower head of the vessel. Different loading combinations were considered based on a wet or dry cavity and pressurization of the vessel based on operating pressure or atmospheric (pipe break). The analyses considered both short term (minutes) and long term (days) failure modes. Short term failure modes include creep at elevated temperatures and plastic instabilities of the structure. Long term failure modes are caused by creep rupture that lead to plastic instability of the structure. The analyses predict the reactor vessel will remain intact after the core melt has deposited on the lower vessel head

  4. Extension of Operating Range in Pump-Turbines. Influence of Head and Load

    Directory of Open Access Journals (Sweden)

    Carme Valero

    2017-12-01

    Full Text Available Due to the increasing share of new renewable energies like wind and solar in the generation of electricity the need for power regulation and energy storage is becoming of paramount importance. One of the systems to store huge amounts of energy is pumped storage using reversible hydropower units. The machines used in these power plants are pump-turbines, which can operate as a pump and as a turbine. The surplus of electrical energy during low consumption hours can be converted into potential hydraulic energy by pumping water to a higher level. The stored energy can be converted into electricity again by operating the runner as a turbine. Due to new regulation requirements machines have to extend the operating range in order to match energy generation with consumption for the grid stability. In this paper the consequences of extending the operating range in existing pump-turbines have been studied. For that purpose, the data obtained after two years of condition monitoring were analyzed. Vibrations and pressure fluctuations of two pump-turbines of 85 MW each have been studied during pump and turbine operation. For turbine operation the effects of extending the operating range from the standard range of 45–85 MW to and increased range of 20–85 MW were analyzed. The change in vibration levels and signatures at very low load are presented with the identification of the phenomena that occur under these conditions. The influence of head in the vibration behavior is also presented. The appearance of fluid instabilities generated at part load that may produce power swing is also presented. Finally, the effect of head on the vibration levels for pump operation is shown and analyzed.

  5. Advanced toroidal facility vaccuum vessel stress analyses

    International Nuclear Information System (INIS)

    Hammonds, C.J.; Mayhall, J.A.

    1987-01-01

    The complex geometry of the Advance Toroidal Facility (ATF) vacuum vessel required special analysis techniques in investigating the structural behavior of the design. The response of a large-scale finite element model was found for transportation and operational loading. Several computer codes and systems, including the National Magnetic Fusion Energy Computer Center Cray machines, were implemented in accomplishing these analyses. The work combined complex methods that taxed the limits of both the codes and the computer systems involved. Using MSC/NASTRAN cyclic-symmetry solutions permitted using only 1/12 of the vessel geometry to mathematically analyze the entire vessel. This allowed the greater detail and accuracy demanded by the complex geometry of the vessel. Critical buckling-pressure analyses were performed with the same model. The development, results, and problems encountered in performing these analyses are described. 5 refs., 3 figs

  6. Exclusive use of arterial grafts in coronary artery bypass operations for three-vessel disease : Use of both thoracic arteries and the gastroepiploic artery in 256 consecutive patients

    NARCIS (Netherlands)

    Grandjean, JG; Voors, AA; Boonstra, PW; denHeyer, P; Ebels, T

    1996-01-01

    Methods: From September 1989 to September 1994 we operated on a consecutive group of 256 patients with three-vessel disease in whom we used the right gastroepiploic artery together with both internal thoracic arteries, Vein grafts were not used in these patients, This population consisted of 233 men

  7. 75 FR 75486 - Maritime Security Directive 104-6 (Rev. 4); Guidelines for U.S. Vessels Operating in High Risk...

    Science.gov (United States)

    2010-12-03

    ... Directive 104-6 (Rev. 4); Guidelines for U.S. Vessels Operating in High Risk Waters AGENCY: Coast Guard, DHS... Maritime Transportation Security Act (MTSA) on international voyages through or in designated high risk... MARSEC Directives are available at your local Captain of the Port (COTP) office. Phone numbers and...

  8. 76 FR 2402 - Maritime Security Directive 104-6 (Rev 5); Guidelines for U.S. Vessels Operating in High Risk Waters

    Science.gov (United States)

    2011-01-13

    ... Directive 104-6 (Rev 5); Guidelines for U.S. Vessels Operating in High Risk Waters AGENCY: Coast Guard, DHS... designated high risk waters, and provides additional counter-piracy guidance and mandatory measures for these... MARSEC Directives are available at your local Captain of the Port (COTP) office. Phone numbers and...

  9. 75 FR 29358 - Maritime Security Directive 104-6 (Rev 2 and 3); Guidelines for U.S. Vessels Operating in High...

    Science.gov (United States)

    2010-05-25

    ... designated high risk waters, and provides additional anti-piracy guidance and mandatory measures for these vessels operating in these areas where acts of piracy and armed robbery against ships are prevalent... piratical activities. The combination of piracy and weak rule of law in the region offers a potential...

  10. Residential CCHP microgrid with load aggregator: Operation mode, pricing strategy, and optimal dispatch

    International Nuclear Information System (INIS)

    Gu, Wei; Lu, Shuai; Wu, Zhi; Zhang, Xuesong; Zhou, Jinhui; Zhao, Bo; Wang, Jun

    2017-01-01

    Highlights: •A bilateral transaction mode for the residential CCHP microgrid is proposed. •An energy pricing strategy for the residential CCHP system is proposed. •A novel integrated demand response for the residential loads is proposed. •Two-stage operation optimization model for the CCHP microgrid is proposed. •Operations of typical days and annual scale of the CCHP microgrid are studied. -- Abstract: As the global energy crisis, environmental pollution, and global warming grow in intensity, increasing attention is being paid to combined cooling, heating, and power (CCHP) systems that realize high-efficiency cascade utilization of energy. This paper proposes a bilateral transaction mechanism between a residential CCHP system and a load aggregator (LA). The variable energy cost of the CCHP system is analyzed, based on which an energy pricing strategy for the CCHP system is proposed. Under this pricing strategy, the electricity price is constant, while the heat/cool price is ladder-shaped and dependent on the relationship between the electrical, heat, and cool loads. For the LA, an integrated demand response program is proposed that combines electricity-load shifting and a flexible heating/cooling supply, in which a thermodynamic model of buildings is used to determine the appropriate range of heating/cooling supply. Subsequently, a two-stage optimal dispatch model is proposed for the energy system that comprises the CCHP system and the LA. Case studies consisting of three scenarios (winter, summer, and excessive seasons) are delivered to demonstrate the effectiveness of the proposed approach, and the performance of the proposed pricing strategy is also evaluated by annual operation simulations.

  11. Improving the extraction-and-loading process in the open mining operations

    Directory of Open Access Journals (Sweden)

    Cheban A. Yu.

    2017-09-01

    Full Text Available Using the explosions is the main way to prepare solid rocks for the excavation, and that results in the formation of a rock mass of uneven granulometric composition, which makes it impossible to use a conveyor quarry transport without the preliminary large crushing of the rock mass obtained during the explosion. A way to achieve the greatest technical and economic effect is the full conveyorization of quarry transport, what, in this case, ensures the sequenced-flow of transport operations, automation of management and high labor productivity. The extraction-and-loading machines are the determining factor in the performance of mining and transport machines in the technological flow of the quarry. When extracting a blasted rock mass with single-bucket excavators or loaders working in combination with bottom-hole conveyors, one uses self-propelled crushing and reloading units of various designs to grind large individual parts to fractions of conditioning size. The presence of a crushing and reloading unit in the pit-face along with the excavator requires an additional space for its placement, complicates the maneuvering of the equipment in the pit-face, and increases the number of personnel and the cost of maintaining the extraction-and-reloading operations. The article proposes an improved method for carrying out the extraction-and-loading process, as well as the design of extraction-and-grinding unit based on a quarry hydraulic excavator. The design of the proposed unit makes it possible to convert the cyclic process of scooping the rock mass into the continuous process of its loading on the bottom-hole conveyor. Using the extraction-and-grinding unit allows one to combine the processes of excavation, preliminary crushing and loading of the rock mass, which ensures an increase in the efficiency of mining operations.

  12. The Impact of Climatological Conditions on Low Enriched Uranium Loading Station Operations for the HEU Blend Down Project

    International Nuclear Information System (INIS)

    Chang, R.C.

    2002-01-01

    A computer model was developed using COREsim to perform a time motion study for the Low Enriched Uranium (LEU) Loading Station operations. The project is to blend Highly Enriched Uranium (HEU) with Natural Uranium (NU) to produce LEU to be shipped to Tennessee Valley Authority (TVA) for further processing. To cope with a project cost reduction, the LEU Loading Station concept has changed from an enclosed building with air-conditioning to a partially enclosed building without air conditioning. The LEU Loading Station is within a radiological contaminated area; two pairs of coveralls and negative pressure respirator are required. As a result, inclement weather conditions, especially heat stress, will affect and impact the LEU loading operations. The purposes of the study are to determine the climatological impacts on LEU Loading operations, resources required for committed throughputs, and to find out the optimum process pathways for multi crews working simultaneously in the space-lim ited LEU Loading Station

  13. Neutron fluence determination for operation effectiveness assessment and prediction of WWER pressure vessel lifetime at the Kozloduy NPP

    Energy Technology Data Exchange (ETDEWEB)

    Apostolov, T; Ilieva, K; Belousov, S; Petrova, T; Antonov, S; Ivanov, K; Prodanova, R; Penev, I; Taskaev, E [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. za Yadrena Izsledvaniya i Yadrena Energetika; Ivanov, I; Tsokov, P; Nelov, N; Lilkov, B; Tsocheva, V; Monev, M; Velichkov, V; Kharalampieva, Ts [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

    1996-12-31

    Embrittlement processes in reactor pressure vessel (RPV) metal have been investigated by neutron dosimetry. A software package for fluence calculations has been developed and used for evaluation of the accumulated neutron fluence, the critical temperature of radiation embrittlement and the RPV lifetime. A digital reactivity meter DR-8 has been introduced for continuous neutron fluence monitoring. Estimates of the neutron fluence and the radiation state of all 6 units of the Kozloduy NPP are presented. The Unit 4 RPV is in the best state regarding metal embrittlement, while the Units 2 and 3 can be safely operated up to the end of their design lifetime only using dummy cassettes. The neutron fluence accumulation in the Unit 1 RPV is quite big and can not be reduced with annealing. Activity measurements of the Unit 1 internal wall shavings are made after the 14-th cycle which show a good agreement with calculated values (1.10{sup 5} Bq/g). The critical embrittlement temperature of the Units 1 - 4 is estimated as a function of the working cycles. 11 figs., 1 tab.

  14. Advanced operational strategy for the IRIS reactor: Load follow through mechanical shim (MSHIM)

    International Nuclear Information System (INIS)

    Franceschini, Fausto; Petrovic, Bojan

    2008-01-01

    design suited for MSHIM operation has been devised. Nine load follow scenarios covering a wide range of possible operating requirements, including Westinghouse design basis plus others proposed by EPRI for Advanced LWRs, have been successfully performed through the control rod banks movement only, without soluble boron adjustment, and maintaining power peaking factors within the acceptable range. Thus, IRIS provides improved operation by enabling load follow through MSHIM

  15. Optimal Operation Method of Smart House by Controllable Loads based on Smart Grid Topology

    Science.gov (United States)

    Yoza, Akihiro; Uchida, Kosuke; Yona, Atsushi; Senju, Tomonobu

    2013-08-01

    From the perspective of global warming suppression and depletion of energy resources, renewable energy such as wind generation (WG) and photovoltaic generation (PV) are getting attention in distribution systems. Additionally, all electrification apartment house or residence such as DC smart house have increased in recent years. However, due to fluctuating power from renewable energy sources and loads, supply-demand balancing fluctuations of power system become problematic. Therefore, "smart grid" has become very popular in the worldwide. This article presents a methodology for optimal operation of a smart grid to minimize the interconnection point power flow fluctuations. To achieve the proposed optimal operation, we use distributed controllable loads such as battery and heat pump. By minimizing the interconnection point power flow fluctuations, it is possible to reduce the maximum electric power consumption and the electric cost. This system consists of photovoltaics generator, heat pump, battery, solar collector, and load. In order to verify the effectiveness of the proposed system, MATLAB is used in simulations.

  16. Size of Left Cardiac Chambers Correlates with Cerebral Microembolic Load in Open Heart Operations

    Directory of Open Access Journals (Sweden)

    Elena Z. Golukhova

    2010-01-01

    Full Text Available Background. Microemboli are a widely recognized etiological factor of cerebral complications in cardiac surgery patients. The present study was aimed to determine if size of left cardiac chambers relates to cerebral microembolic load in open heart operations. Methods. Thirty patients participated in the study. Echocardiography was performed in 2-3 days before surgery. A transcranial Doppler system was used for registering intraoperative microemboli. Results. Preoperative left atrium and left ventricular end-systolic and end-diastolic sizes significantly correlated with intraoperative microembolic load (s=0.48, 0.57 and 0.53, s≺.01, resp.. The associations between left ventricular diameters and number of cerebral microemboli remained significant when cardiopulmonary bypass time was included as a covariate into the analysis. Conclusions. The present results demonstrate that increased size of left heart chambers is an influential risk factor for elevated cerebral microembolic load during open heart operations. Mini-invasive surgery and carbon dioxide insufflation into wound cavity may be considered as neuroprotective approaches in patients with high risk of cerebral microembolism.

  17. Evaluation of reactivity and Xe behavior during daily load following operation

    International Nuclear Information System (INIS)

    Sakamoto, Yasunori; Araki, Tsuneyasu; Yamamoto, Fumiaki

    1992-01-01

    A boiling water reactor (BWR) has an excellent load following capability provided by a core flow control, which is used for changing a reactor power level and for compensating the subsequent Xe concentration change. The core characteristics during load following operations are investigated in detail, using our reactor core simulator. Comparisons of changes of the Doppler reactivity, the void reactivity and the Xe reactivity during transients are performed. Also the features of Xe transient during load following operations are shown. It has been shown that the core flow change required to compensate the Xe reactivity change produces much greater change of the void reactivity than that required for power level changes, and that the resulting local power change in the lower part of the core is greater than that in the upper part, because the Xe concentration change in the lower part is hardly compensated by the core flow control. Also the effects of power level changes, cycle patterns, and initial concentration of Xe and I on the Xe transient behavior have been investigated. (author)

  18. Power control method for load-frequency control operation in BWRs

    International Nuclear Information System (INIS)

    Ie, Shin-ichiroo; Ohgo, Yu-kiharu; Itou, Tetsuo; Shida, Tooichi

    1991-01-01

    The preliminary design of an advanced power control method for fast load-following [load frequency control (LFC)] maneuvers in a boiling water reactor (BWR) is described in this paper. Application of a multivariable control method using an optimal linear quadratic (LQ) regulator theory effectively improves control system performance when system variables have significant interactions such as in BWRs. The control problem, however, demands strict constraints on system variable from the standpoint of plant operation. These constraints require the control system to have a nonlinear property for better improvement. Therefore, the effectiveness of LQ control is limited by these constraints, because it is based on a linear model. A new method is needed to compensate for the nonlinear property. In this study, the authors propose a new method using fuzzy reasoning with LQ control to achieve nonlinear compensation

  19. The use of inverse systems in computerized operator support systems for load-following control

    International Nuclear Information System (INIS)

    Klebau, J.; Hentschel, B.; Ziegenbein, D.

    1987-01-01

    The basic problem in load-following control of nuclear power reactors consists in calculation of control rod movement to realize desired local power density distribution in the reactor. Well-known solutions are based on optimal control theory. The paper describes the concept of systems inverses which makes it possible to solve the load-following control problem not in an optimal but in an 'ideal' way, vanishing the optimization criterion of the classical approaches. The advantages of inverse systems are simple calculation procedures, low on-line-storage capacity and low on-line computational amount. This makes it attractive to use inverse systems in computerized operator support systems. 19 refs. (author)

  20. Thermal loads on tokamak plasma-facing components during normal operation and disruptions

    International Nuclear Information System (INIS)

    McGrath, R.T.

    1990-01-01

    Power loadings experienced by tokamak plasma-facing components during normal operation and during off-normal events are discussed. A model for power and particle flow in the tokamak boundary layer is presented and model predictions are compared to infrared measurements of component heating. The inclusion of the full three-dimensional geometry of the components and of the magnetic flux surface is very important in the modeling. Experimental measurements show that misalignment of component armour tile surfaces by only a millimeter can lead to significant localized heating. An application to the design of plasma-facing components for future machines is presented. Finally, thermal loads expected during tokamak disruptions are discussed. The primary problems are surface melting and vaporization due to localized intense heating during the disruption thermal quench and volumetric heating of the component armour and structure due to localised impact of runaway electrons. (author)

  1. A Heuristic Procedure for the Outbound Container Relocation Problem during Export Loading Operations

    Directory of Open Access Journals (Sweden)

    Roberto Guerra-Olivares

    2015-01-01

    Full Text Available During export ship loading operations, it is often necessary to perform relocation movements with containers that interfere with access to the desired container in the ship loading sequence. This paper presents a real-time heuristic procedure for the container relocation problem employing reachstacker vehicles as container handling equipment. The proposed heuristic searches for good relocation coordinates within a set of nearby bays. The heuristic has a parameter that determines how far from the original bay a container may be relocated. The tradeoff between reducing relocation movements and limiting vehicle travel distances is examined and the performance of the heuristic is compared with a common practice in the smaller container terminals in Chile and Mexico. Finally, a mathematical model for the container relocation problem is presented.

  2. Behaviour of a pressure vessel nozzle with thermo-sleeve under thermal loading induced by stratified flow

    International Nuclear Information System (INIS)

    Kussmaul, K.; Mayinger, W.; Diem, H.; Katzenmeier, G.

    1993-01-01

    Startup at low reactor power may give rise to stratified flow conditions in pipes of boiling water and pressurized water reactors. Stratified flow regimes cause a steep temperature gradient between the cold and the hot fluid layer. This temperature gradient produces high axial stresses which, in the case of intermittent feeding of cold water and an appropriate number of repetitions, in principle may initiate cracking in the feedwater pipe and close to the feeding nozzle. Thermosleeves have been installed in a number of reactors to mitigate thermally induced stresses; they reduce the intensity of thermal transients by means of an insulating fluid annulus developing between the sleeve and the nozzle, in order to measure the temperature and stress gradients occurring in the region of the nozzle edge, the so-called TEMS experiments were carried out under realistic operating conditions, and with different cold water levels within the framework of German research activities in the field of reactor safety at the HDR test facility. The experiments served to simulate the physics phenomena by means of a FE-program and to verify the computational approach by comparisons of measurements and calculations

  3. In-vessel maintenance remote manipulator system

    International Nuclear Information System (INIS)

    Jimenez, E.

    1978-01-01

    The radiation environment within the Tokamak Fusion Test Reactor (TFTR) vacuum vessel necessitates the development of a Remote Manipulator System (RMS) to perform required periodic inspection and maintenance tasks. The RMS must be able to perform dexterous operations and handle loads that exceed human capabilities. The limited size of the access ports on the TFTR vacuum vessel and the performance profile, defined by the various handling requirements, present unique design constraints. The design approach and formulation of a RMS configuration which satisfies TFTR requirements is presented herein

  4. On thermoeconomics of energy systems at variable load conditions: Integrated optimization of plant design and operation

    International Nuclear Information System (INIS)

    Piacentino, A.; Cardona, F.

    2007-01-01

    Thermoeconomics has been assuming a growing role among the disciplines oriented to the analysis of energy systems, its different methodologies allowing solution of problems in the fields of cost accounting, plant design optimisation and diagnostic of malfunctions. However, the thermoeconomic methodologies as such are particularly appropriate to analyse large industrial systems at steady or quasi-steady operation, but they can be hardly applied to small to medium scale units operating in unsteady conditions to cover a variable energy demand. In this paper, the fundamentals of thermoeconomics for systems operated at variable load are discussed, examining the cost formation process and, separately, the cost fractions related to capital depreciation (which require additional distinctions with respect to plants in steady operation) and to exergy consumption. The relevant effects of the efficiency penalty due to off design operation on the exergetic cost of internal flows are also examined. An original algorithm is proposed for the integrated optimization of plant design and operation based on an analytical solution by the Lagrange multipliers method and on a multi-objective decision function, expressed either in terms of net cash flow or primary energy saving. The method is suitable for application in complex energy systems, such as 'facilities of components of a same product' connected to external networks for power or heat distribution. For demonstrative purposes, the proposed thermoeconomically aided optimization is performed for a grid connected trigeneration system to be installed in a large hotel

  5. Methodologies for estimating air emissions from three non-traditional source categories: Oil spills, petroleum vessel loading and unloading, and cooling towers. Final report, October 1991-March 1993

    International Nuclear Information System (INIS)

    Ramadan, W.; Sleva, S.; Dufner, K.; Snow, S.; Kersteter, S.L.

    1993-04-01

    The report discusses part of EPA's program to identify and characterize emissions sources not currently accounted for by either the existing Aerometric Information Retrieval System (AIRS) or State Implementation Plan (SIP) area source methodologies and to develop appropriate emissions estimation methodologies and emission factors for a group of these source categories. Based on the results of the identification and characterization portions of this research, three source categories were selected for methodology and emission factor development: oil spills, petroleum vessel loading and unloading, and cooling towers. The report describes the category selection process and presents emissions estimation methodologies and emission factor data for the selected source categories. The discussions for each category include general background information, emissions generation activities, pollutants emitted, sources of activity and pollutant data, emissions estimation methodologies and data issues. The information used in these discussions was derived from various sources including available literature, industrial and trade association publications and contracts, experts on the category and activity, and knowledgeable federal and state personnel

  6. Recent development for improving of PWR flexibility to load follow and frequency control operation

    International Nuclear Information System (INIS)

    Dubourg, M.

    1983-08-01

    In order to adjust the PWR electricity generation to the consumption network, new operating conditions were established. Those new conditions generate additional mechanical and thermal sollicitations due to the frequent motion of control rod banks, consisting of mechanical fatigue cycling and wear at the level of control rode drive mechanisms, control rods and guide tubes, wear and thermal fatigue cycling at the level of fuel assemblies. This paper presents the various aspects of this program including identification of the most critical areas of components, basic research in laboratories for resolving wear problems in PWR environment, improvement of local hydraulics for reducing loads, and endurance testing of full scale components on testing facilities

  7. Validation Tests of Fiber Optic Strain-Based Operational Shape and Load Measurements

    Science.gov (United States)

    Bakalyar, John A.; Jutte, Christine

    2012-01-01

    Aircraft design has been progressing toward reduced structural weight to improve fuel efficiency, increase performance, and reduce cost. Lightweight aircraft structures are more flexible than conventional designs and require new design considerations. Intelligent sensing allows for enhanced control and monitoring of aircraft, which enables increased structurally efficiency. The NASA Dryden Flight Research Center (DFRC) has developed an instrumentation system and analysis techniques that combine to make distributed structural measurements practical for lightweight vehicles. Dryden's Fiber Optic Strain Sensing (FOSS) technology enables a multitude of lightweight, distributed surface strain measurements. The analysis techniques, referred to as the Displacement Transfer Functions (DTF) and Load Transfer Functions (LTF), use surface strain values to calculate structural deflections and operational loads. The combined system is useful for real-time monitoring of aeroelastic structures, along with many other applications. This paper describes how the capabilities of the measurement system were demonstrated using subscale test articles that represent simple aircraft structures. Empirical FOSS strain data were used within the DTF to calculate the displacement of the article and within the LTF to calculate bending moments due to loads acting on the article. The results of the tests, accuracy of the measurements, and a sensitivity analysis are presented.

  8. Event-based scenario manager for multibody dynamics simulation of heavy load lifting operations in shipyards

    Directory of Open Access Journals (Sweden)

    Sol Ha

    2016-01-01

    Full Text Available This paper suggests an event-based scenario manager capable of creating and editing a scenario for shipbuilding process simulation based on multibody dynamics. To configure various situation in shipyards and easily connect with multibody dynamics, the proposed method has two main concepts: an Actor and an Action List. The Actor represents the anatomic unit of action in the multibody dynamics and can be connected to a specific component of the dynamics kernel such as the body and joint. The user can make a scenario up by combining the actors. The Action List contains information for arranging and executing the actors. Since the shipbuilding process is a kind of event-based sequence, all simulation models were configured using Discrete EVent System Specification (DEVS formalism. The proposed method was applied to simulations of various operations in shipyards such as lifting and erection of a block and heavy load lifting operation using multiple cranes.

  9. Analysis for Involvement of TPP Operating in Accordance with Heating Schedule to Passing Through Failures of Electric Load Schedules

    Directory of Open Access Journals (Sweden)

    V. I. Nazarov

    2013-01-01

    Full Text Available The paper describes technical and economic evaluation of various methods pertaining to passing through failures of electric load at TPP which is operating in accordance with heating schedule.

  10. Optimal distribution of reactivity excess in a system of reactors operating at a variable loading schedule

    International Nuclear Information System (INIS)

    Bolsunov, A.A.; Zagrebaev, A.M.; Naumov, V.I.

    1979-01-01

    Considered is the task of reactivity excess distribution optimization in the system of reactors for the purpose of minimazing the summary power production losses at the fixed loading schedule. Mathematical formulation of the task is presented. Given are the curves, characterizing the dependence of possible degree of the reactor power drop on reactivity excees for non-stationary Xe poisoning at different nominal density of neutron flux. Analyzing the results, it is concluded that in case, when the reactors differ only in neutron flux density the reactor with lower neutron flux density should be involved in the variable operation schedule first as the poisoning of this reactor will be less, and therefore, the losses of the system power production will be less. It is advisable to reserve the reactivity excess in the reactor with greater power or in the reactor with higher burnup rate. It is stressed that the obtained results of the optimization task solution point out the possibility of obtaining the certain ecomonic effect and permit to correct the requirements on mobility of separate power units at system approach to NPP operation in a variable loading schedule

  11. IMPROVEMENT OF PERFORMANCE OF DUAL FUEL ENGINE OPERATED AT PART LOAD

    Directory of Open Access Journals (Sweden)

    N. Kapilan

    2010-12-01

    Full Text Available Rising petroleum prices, an increasing threat to the environment from exhaust emissions, global warming and the threat of supply instabilities has led to the choice of inedible Mahua oil (MO as one of the main alternative fuels to diesel oil in India. In the present work, MO was converted into biodiesel by transesterification using methanol and sodium hydroxide. The cost of Mahua oil biodiesel (MOB is higher than diesel. Hence liquefied petroleum gas (LPG, which is one of the cheapest gaseous fuels available in India, was fumigated along with the air to reduce the operating cost and to reduce emissions. The dual fuel engine resulted in lower efficiency and higher emissions at part load. Hence in the present work, the injection time was varied and the performance of the dual fuel engine was studied. From the engine tests, it is observed that an advanced injection time results in higher efficiency and lower emissions. Hence, advancing the injection timing is one of the ways of increasing the efficiency of LPG+MOB dual fuel engine operated at part load.

  12. Seismic transient analysis of a containment vessel with penetrations

    International Nuclear Information System (INIS)

    Dahlke, H.J.; Weiner, E.O.

    1979-12-01

    A linear transient analysis of the FFTF containment vessel was conducted with STAGS to justify the load levels used for the seismic qualification testing of the heating and ventiliation valve operators. The modeling consists of a thin axisymmetric shell for the containment vessel with four penetrations characterized by linear and rotational inertias as well as attachment characteristics to the shell. Motions considered are horizontal, rocking and vertical input to the base, and the solution is carried out by direct integration. Results show that the test levels and the approximate analyses considered are conservative. Response spectra for some containment vessel penetrations applicable to the model are presented

  13. Operation and Management of Thermostatically Controlled Loads for Providing Regulation Services to Power Grids

    Science.gov (United States)

    Vanouni, Maziar

    The notion of demand-side participation in power systems operation and control is on the verge of realization because of the advancement in the required technologies an tools like communications, smart meters, sensor networks, large data management techniques, large scale optimization method, etc. Therefore, demand-response (DR) programs can be one of the prosperous solutions to accommodate part of the increasing demand for load balancing services which is brought about by the high penetration of intermittent renewable energies in power systems. This dissertation studies different aspects of the DR programs that utilized the thermostatically controlled loads (TCLs) to provide load balancing services. The importance of TCLs among the other loads lie on their flexibility in power consumption pattern while the customer/end-user comfort is not (or minimally) impacted. Chapter 2 discussed a previously presented direct load control (DLC) to control the power consumption of aggregated TCLs. The DLC method performs a power tracking control and based on central approach where a central controller broadcasts the control command to the dispersed TCLs to toggle them on/off. The central controller receives measurement feedback from the TCLs once per couple of minutes to run a successful forecast process. The performance evaluation criteria to evaluate the load balancing service provided by the TCLs are presented. The results are discussed under different scenarios and situation. The numerical results show the proper performance of the DLC method. This DLC method is used as the control method in all the studies in this dissertation. Chapter 3 presents performance improvements for the original method in Chapter 2 by communicating two more pieces of information called forecast parameters (FPs). Communicating improves the forecast process in the DLC and hence, both performance accuracy and the amount of tear-and-wear imposed on the TCLs. Chapter 4 formulates a stochastic

  14. Marine pollution originating from purse seine and longline fishing vessel operations in the Western and Central Pacific Ocean, 2003-2015.

    Science.gov (United States)

    Richardson, Kelsey; Haynes, David; Talouli, Anthony; Donoghue, Michael

    2017-03-01

    Fisheries observer data recorded between 2003 and 2015 on-board purse seine and longline vessels operating in the Western and Central Pacific Ocean reported more than 10 000 pollution incidents within the exclusive economic zones (EEZs) of 25 Pacific countries and territories, and in international waters. A majority of the reported purse seine pollution incidents related to dumping of plastics waste. Other common pollution incidents related to oil spillages and to abandoned, lost or dumped fishing gear. Data analysis highlighted the need for increased monitoring, reporting, and enforcement of pollution violations by all types of fishing vessels operating in the Pacific region; a regional outreach and compliance assistance programme on marine pollution prevention and improvements in Pacific port waste reception facilities.

  15. Study on operation conditions and an operation system of a nuclear powered submersible research vessel, 'report of working group on application of a very small nuclear reactor to an ocean research'

    International Nuclear Information System (INIS)

    Ura, Tamaki; Takamasa, Tomoji; Nishimura, Hajime

    2001-07-01

    JAERI has studied on design of a nuclear powered submersible research vessel, which will navigate under sea mainly in the Arctic Ocean, as a part of the design activity of advanced marine reactors. This report describes operation conditions and an operating system of the vessel, which were discussed by the specialists of hull design, sound positioning, ship motions and oceanography, etc. The design conditions on ship motions for submersible vessels were surveyed considering regulations in our country, and ship motions were evaluated in the cases of underwater and surface navigations taking account of observation activities in the Arctic Ocean. The effect of ship motions on the compact nuclear reactor SCR was assessed. A submarine transponder system and an on-ice communication buoy system were examined as a positioning and communication system, supposing the activity under ice. The interval between transponders or communication buoys was recommended as 130 km. Procedures to secure safety of nuclear powered submersible research vessel were discussed according to accidents on the hull or the nuclear reactor. These results were reflected to the concept of the nuclear powered submersible research vessel, and subjects to be settled in the next step were clarified. (author)

  16. Study on operation conditions and an operation system of a nuclear powered submersible research vessel, 'report of working group on application of a very small nuclear reactor to an ocean research'

    Energy Technology Data Exchange (ETDEWEB)

    Ura, Tamaki [Tokyo Univ., Tokyo (Japan); Takamasa, Tomoji [Tokyo Univ. of Mercantile Marine, Tokyo (Japan); Nishimura, Hajime [Japan Marine Science and Technology Center, Yokosuka, Kanagawa (JP)] [and others

    2001-07-01

    JAERI has studied on design of a nuclear powered submersible research vessel, which will navigate under sea mainly in the Arctic Ocean, as a part of the design activity of advanced marine reactors. This report describes operation conditions and an operating system of the vessel, which were discussed by the specialists of hull design, sound positioning, ship motions and oceanography, etc. The design conditions on ship motions for submersible vessels were surveyed considering regulations in our country, and ship motions were evaluated in the cases of underwater and surface navigations taking account of observation activities in the Arctic Ocean. The effect of ship motions on the compact nuclear reactor SCR was assessed. A submarine transponder system and an on-ice communication buoy system were examined as a positioning and communication system, supposing the activity under ice. The interval between transponders or communication buoys was recommended as 130 km. Procedures to secure safety of nuclear powered submersible research vessel were discussed according to accidents on the hull or the nuclear reactor. These results were reflected to the concept of the nuclear powered submersible research vessel, and subjects to be settled in the next step were clarified. (author)

  17. Fuel element cladding state change mathematical model for a WWER-1000 plant operated in the mode of varying loading

    Directory of Open Access Journals (Sweden)

    S. N. Pelykh

    2010-09-01

    Full Text Available Main features of a fuel element cladding state change mathematical model for a WWER-1000 reactor plant operated in the mode of varying loading are listed. The integrated model is based on the energy creep theory, uses the finite element method for imultaneous solution of the fuel element heat conduction and mechanical deformation equa-tions. Proposed mathematical model allows us to determine the influence of the WWER-1000 regime parameters and fuel assembly design characteristics on the change of cladding properties under different loading conditions of normal operation, as well as the cladding limiting state at variable loading depending on the length, depth and number of cycles.

  18. Is the bipolar vessel sealer device an effective tool in robotic surgery? A retrospective analysis of our experience and a meta-analysis of the literature about different robotic procedures by investigating operative data and post-operative course.

    Science.gov (United States)

    Ortenzi, Monica; Ghiselli, Roberto; Baldarelli, Maddalena; Cardinali, Luca; Guerrieri, Mario

    2018-04-01

    The latest robotic bipolar vessel sealing tools have been described to be effective allowing to perform procedures with reduced blood loss and shorter operative times. The aim of this study was to assess the efficacy and reliability of these devices applied in different robotic procedures. All robotic operations, between 2014 and 2016, were performed using the EndoWrist One VesselSealer (EWO, Intuitive Surgical, Sunnyvale, CA), a bipolar fully wristed device. Data, including age, gender, body mass index (BMI), were collected. Robot docking time, intraoperative blood loss, robot malfunctioning and overall operative time were analyzed. A meta-analysis of the literature was carried out to point the attention to three different parameters (mean blood loss, operating time and hospital stay) trying to identify how different coagulation devices may affect them. In 73 robotic procedures, the mean operative time was 118.2 minutes (75-125 minutes). Mean hospital stay was four days (2-10 days). There were two post-operative complications (2.74%). The bipolar vessel sealer offers the efficacy of bipolar diathermy and the advantages of a fully wristed instrument. It does not require any change of instruments for coagulation or involvement of the bedside assistant surgeon. These characteristics lead to a reduction in operative time.

  19. Robust nonlinear model predictive control for nuclear power plants in load following operations with bounded xenon oscillations

    International Nuclear Information System (INIS)

    Eliasi, H.; Menhaj, M.B.; Davilu, H.

    2011-01-01

    Research highlights: → In this work, a robust nonlinear model predictive control algorithm is developed. → This algorithm is applied to control the power level for load following. → The state constraints are imposed on the predicted trajectory during optimization. → The xenon oscillations are the main constraint for the load following problem. → In this algorithm, xenon oscillations are bounded within acceptable limits. - Abstract: One of the important operations in nuclear power plants is load-following in which imbalance of axial power distribution induces xenon oscillations. These oscillations must be maintained within acceptable limits otherwise the nuclear power plant could become unstable. Therefore, bounded xenon oscillation considered to be a constraint for the load-following operation. In this paper, a robust nonlinear model predictive control for the load-following operation problem is proposed that ensures xenon oscillations are kept bounded within acceptable limits. The proposed controller uses constant axial offset (AO) strategy to maintain xenon oscillations to be bounded. The constant AO is a robust state constraint for load-following problem. The controller imposes restricted state constraints on the predicted trajectory during optimization which guarantees robust satisfaction of state constraints without restoring to a min-max optimization problem. Simulation results show that the proposed controller for the load-following operation is so effective so that the xenon oscillations kept bounded in the given region.

  20. Blood pressure regulation V: in vivo mechanical properties of precapillary vessels as affected by long-term pressure loading and unloading.

    Science.gov (United States)

    Eiken, Ola; Mekjavic, Igor B; Kölegård, Roger

    2014-03-01

    Recent studies are reviewed, concerning the in vivo wall stiffness of arteries and arterioles in healthy humans, and how these properties adapt to iterative increments or sustained reductions in local intravascular pressure. A novel technique was used, by which arterial and arteriolar stiffness was determined as changes in arterial diameter and flow, respectively, during graded increments in distending pressure in the blood vessels of an arm or a leg. Pressure-induced increases in diameter and flow were smaller in the lower leg than in the arm, indicating greater stiffness in the arteries/arterioles of the leg. A 5-week period of intermittent intravascular pressure elevations in one arm reduced pressure distension and pressure-induced flow in the brachial artery by about 50%. Conversely, prolonged reduction of arterial/arteriolar pressure in the lower body by 5 weeks of sustained horizontal bedrest, induced threefold increases of the pressure-distension and pressure-flow responses in a tibial artery. Thus, the wall stiffness of arteries and arterioles are plastic properties that readily adapt to changes in the prevailing local intravascular pressure. The discussion concerns mechanisms underlying changes in local arterial/arteriolar stiffness as well as whether stiffness is altered by changes in myogenic tone and/or wall structure. As regards implications, regulation of local arterial/arteriolar stiffness may facilitate control of arterial pressure in erect posture and conditions of exaggerated intravascular pressure gradients. That increased intravascular pressure leads to increased arteriolar wall stiffness also supports the notion that local pressure loading may constitute a prime mover in the development of vascular changes in hypertension.

  1. Computational hydrodynamic comparison of a mini vessel and a USP 2 dissolution testing system to predict the dynamic operating conditions for similarity of dissolution performance.

    Science.gov (United States)

    Wang, Bing; Bredael, Gerard; Armenante, Piero M

    2018-03-25

    The hydrodynamic characteristics of a mini vessel and a USP 2 dissolution testing system were obtained and compared to predict the tablet-liquid mass transfer coefficient from velocity distributions near the tablet and establish the dynamic operating conditions under which dissolution in mini vessels could be conducted to generate concentration profiles similar to those in the USP 2. Velocity profiles were obtained experimentally using Particle Image Velocimetry (PIV). Computational Fluid Dynamics (CFD) was used to predict the velocity distribution and strain rate around a model tablet. A CFD-based mass transfer model was also developed. When plotted against strain rate, the predicted tablet-liquid mass transfer coefficient was found to be independent of the system where it was obtained, implying that a tablet would dissolve at the same rate in both systems provided that the concentration gradient between the tablet surface and the bulk is the same, the tablet surface area per unit liquid volume is identical, and the two systems are operated at the appropriate agitation speeds specified in this work. The results of this work will help dissolution scientists operate mini vessels so as to predict the dissolution profiles in the USP 2, especially during the early stages of drug development. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Modeling Relevant to Safe Operations of U.S. Navy Vessels in Arctic Conditions: Physical Modeling of Ice Loads

    Science.gov (United States)

    2016-06-01

    Proceedings of the ASME 31st International Conference on Ocean, Offshore and Arctic Engineering, 1–6 July, Rio de Janeiro , Brazil, 6:495–505. New York...Arctic Engineering, 1–6 July, Rio de Janeiro , Brazil, 6:495–505. New York, NY: American Society of Mechanical Engineers. doi:10.1115/OMAE2012-83927...of ice impacts with Navy ships. These large-scale tests will provide important benchmark data to support the de - velopment of numerical testbeds

  3. Hybrid power system intelligent operation and protection involving distributed architectures and pulsed loads

    Science.gov (United States)

    Mohamed, Ahmed

    Efficient and reliable techniques for power delivery and utilization are needed to account for the increased penetration of renewable energy sources in electric power systems. Such methods are also required for current and future demands of plug-in electric vehicles and high-power electronic loads. Distributed control and optimal power network architectures will lead to viable solutions to the energy management issue with high level of reliability and security. This dissertation is aimed at developing and verifying new techniques for distributed control by deploying DC microgrids, involving distributed renewable generation and energy storage, through the operating AC power system. To achieve the findings of this dissertation, an energy system architecture was developed involving AC and DC networks, both with distributed generations and demands. The various components of the DC microgrid were designed and built including DC-DC converters, voltage source inverters (VSI) and AC-DC rectifiers featuring novel designs developed by the candidate. New control techniques were developed and implemented to maximize the operating range of the power conditioning units used for integrating renewable energy into the DC bus. The control and operation of the DC microgrids in the hybrid AC/DC system involve intelligent energy management. Real-time energy management algorithms were developed and experimentally verified. These algorithms are based on intelligent decision-making elements along with an optimization process. This was aimed at enhancing the overall performance of the power system and mitigating the effect of heavy non-linear loads with variable intensity and duration. The developed algorithms were also used for managing the charging/discharging process of plug-in electric vehicle emulators. The protection of the proposed hybrid AC/DC power system was studied. Fault analysis and protection scheme and coordination, in addition to ideas on how to retrofit currently available

  4. Reactor vessel head permanent shield

    International Nuclear Information System (INIS)

    Hankinson, M.F.; Leduc, R.J.; Richard, J.W.; Malandra, L.J.

    1989-01-01

    A nuclear reactor is described comprising: a nuclear reactor pressure vessel closure head; control rod drive mechanisms (CRDMs) disposed within the closure head so as to project vertically above the closure head; cooling air baffle means surrounding the control rod drive mechanisms for defining cooling air paths relative to the control rod drive mechanisms; means defined within the periphery of the closure head for accommodating fastening means for securing the closure head to its associated pressure vessel; lifting lugs fixedly secured to the closure head for facilitating lifting and lowering movements of the closure head relative to the pressure vessel; lift rods respectively operatively associated with the plurality of lifting lugs for transmitting load forces, developed during the lifting and lowering movements of the closure head, to the lifting lugs; upstanding radiation shield means interposed between the cooling air baffle means and the periphery of the enclosure head of shielding maintenance personnel operatively working upon the closure head fastening means from the effects of radiation which may emanate from the control rod drive mechanisms and the cooling air baffle means; and connecting systems respectively associated with each one of the lifting lugs and each one of the lifting rods for connecting each one of the lifting rods to a respective one of each one of the lifting lugs, and for simultaneously connecting a lower end portion of the upstanding radiation shield means to each one of the respective lifting lugs

  5. Availability analysis of a turbocharged diesel engine operating under transient load conditions

    International Nuclear Information System (INIS)

    Rakopoulos, C.D.; Giakoumis, E.G.

    2004-01-01

    A computer analysis is developed for studying the energy and availability performance of a turbocharged diesel engine, operating under transient load conditions. The model incorporates many novel features for the simulation of transient operation, such as detailed analysis of mechanical friction, separate consideration for the processes of each cylinder during a cycle ('multi-cylinder' model) and mathematical modeling of the fuel pump. This model has been validated against experimental data taken from a turbocharged diesel engine, located at the authors' laboratory and operated under transient conditions. The availability terms for the diesel engine and its subsystems are analyzed, i.e. cylinder for both the open and closed parts of the cycle, inlet and exhaust manifolds, turbocharger and aftercooler. The present analysis reveals, via multiple diagrams, how the availability properties of the diesel engine and its subsystems develop during the evolution of the engine cycles, assessing the importance of each property. In particular the irreversibilities term, which is absent from any analysis based solely on the first-law of thermodynamics, is given in detail as regards transient response as well as the rate and cumulative terms during a cycle, revealing the magnitude of contribution of all the subsystems to the total availability destruction

  6. Modeling and measurement of the motion of the DIII-D vacuum vessel during vertical instabilities

    International Nuclear Information System (INIS)

    Reis, E.; Blevins, R.D.; Jensen, T.H.; Luxon, J.L.; Petersen, P.I.; Strait, E.J.

    1991-11-01

    The motions of the D3-D vacuum vessel during vertical instabilities of elongated plasmas have been measured and studied over the past five years. The currents flowing in the vessel wall and the plasma scrapeoff layer were also measured and correlated to a physics model. These results provide a time history load distribution on the vessel which were input to a dynamic analysis for correlation to the measured motions. The structural model of the vessel using the loads developed from the measured vessel currents showed that the calculated displacement history correlated well with the measured values. The dynamic analysis provides a good estimate of the stresses and the maximum allowable deflection of the vessel. In addition, the vessel motions produce acoustic emissions at 21 Hertz that are sufficiently loud to be felt as well as heard by the D3-D operators. Time history measurements of the sounds were correlated to the vessel displacements. An analytical model of an oscillating sphere provided a reasonable correlation to the amplitude of the measured sounds. The correlation of the theoretical and measured vessel currents, the dynamic measurements and analysis, and the acoustic measurements and analysis show that: (1) The physics model can predict vessel forces for selected values of plasma resistivity. The model also predicts poloidal and toroidal wall currents which agree with measured values; (2) The force-time history from the above model, used in conjunction with an axisymmetric structural model of the vessel, predicts vessel motions which agree well with measured values; (3) The above results, input to a simple acoustic model predicts the magnitude of sounds emitted from the vessel during disruptions which agree with acoustic measurements; (4) Correlation of measured vessel motions with structural analysis shows that a maximum vertical motion of the vessel up to 0.24 in will not overstress the vessel or its supports. 11 refs., 10 figs., 1 tab

  7. Pressure vessel design manual

    CERN Document Server

    Moss, Dennis R

    2013-01-01

    Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. * Covers almost all problems that a working pressure vessel designer can expect to face, with ...

  8. Staff Technical Position on geological repository operations area underground facility design: Thermal loads

    International Nuclear Information System (INIS)

    Nataraja, M.S.

    1992-12-01

    The purpose of this Staff Technical Position (STP) is to provide the US Department of Energy (DOE) with a methodology acceptable to the Nuclear Regulatory Commission staff for demonstrating compliance with 10 CFR 60.133(i). The NRC staff's position is that DOE should develop and use a defensible methodology to demonstrate the acceptability of a geologic repository operations area (GROA) underground facility design. The staff anticipates that this methodology will include evaluation and development of appropriately coupled models, to account for the thermal, mechanical, hydrological, and chemical processes that are induced by repository-generated thermal loads. With respect to 10 CFR 60.133(i), the GROA underground facility design: (1) should satisfy design goals/criteria initially selected, by considering the performance objectives; and (2) must satisfy the performance objectives 10 CFR 60.111, 60.112, and 60.113. The methodology in this STP suggests an iterative approach suitable for the underground facility design

  9. NVENTIONS IN THE NANOTECHNOLOGICAL AREA PROVIDE INCREASED RESISTANCE OF CONSTRUCTION MATERIALS AND PRODUCTS TO OPERATIONAL LOAD

    Directory of Open Access Journals (Sweden)

    VLASOV Vladimir Alexeevich

    2013-12-01

    Full Text Available The invention «Dispersion of Carbon Nanotubes (RU 2494961» can be used in production of modifying additives for construction materials. Dispersion of carbon nanotubes contains, mass %: carbon nanotubes 1–20; surface active agent – sodium chloride of sulfonated derived naphthalene 1–20; fumed silica 5–15; water – the rest. Dispersion can additionally contain ethylene glycol as antifreeze. Dispersion is steady in storage, it is soluble in water, provides increased strength of construction materials. Invention «Building Structures Reinforcement Composition (RU 2493337» can beused in construction to reinforce concrete, brick and masonry structures. Composition contains glass or basalt roving taken in quantity 90÷100 parts by weight, soaked in polymer binder based on epoxy taken in quantity 0,001÷1,5 parts by weight. This invention provides high resistance to operational load.

  10. Research vessels

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.

    The role of the research vessels as a tool for marine research and exploration is very important. Technical requirements of a suitable vessel and the laboratories needed on board are discussed. The history and the research work carried out...

  11. Containment vessel drain system

    Science.gov (United States)

    Harris, Scott G.

    2018-01-30

    A system for draining a containment vessel may include a drain inlet located in a lower portion of the containment vessel. The containment vessel may be at least partially filled with a liquid, and the drain inlet may be located below a surface of the liquid. The system may further comprise an inlet located in an upper portion of the containment vessel. The inlet may be configured to insert pressurized gas into the containment vessel to form a pressurized region above the surface of the liquid, and the pressurized region may operate to apply a surface pressure that forces the liquid into the drain inlet. Additionally, a fluid separation device may be operatively connected to the drain inlet. The fluid separation device may be configured to separate the liquid from the pressurized gas that enters the drain inlet after the surface of the liquid falls below the drain inlet.

  12. Reactor vessel supported by flexure member

    International Nuclear Information System (INIS)

    Crawford, J.D.; Pankow, B.

    1977-01-01

    According to the present invention there is provided an improved arrangement for supporting a reactor vessel within a containment structure against static and dynamic vertical loadings capable of being imposed as a result of a serious accident as well as during periods of normal plant operation. The support arrangement of the invention is, at the same time, capable of accommodating radial displacements that normally occur between the reactor vessel and the containment structure due to operational transients. The arrangement comprises a plurality of vertical columns connected between the reactor vessel and a support base within the containment structure. The columns are designed to accommodate relative displacements between the vessel and the containment structure by flexing. This eliminates the need for relative sliding movements and thus enables the columns to be securely fixed to the vessel. This elimination of a provision for relative sliding movements avoids the spaces or gaps between the retention members and the retained elements as occurred in prior art arrangements and, concomitantly, the danger of establishing impact forces on the retention members in the event of an accident is reduced. (author)

  13. Two-Stage Load Shedding for Secondary Control in Hierarchical Operation of Islanded Microgrids

    DEFF Research Database (Denmark)

    Zhou, Quan; Li, Zhiyi; Wu, Qiuwei

    2018-01-01

    A two-stage load shedding scheme is presented to cope with the severe power deficit caused by microgrid islanding. Coordinated with the fast response of inverter-based distributed energy resources (DERs), load shedding at each stage and the resulting power flow redistribution are estimated....... The first stage of load shedding will cease rapid frequency decline in which the measured frequency deviation is employed to guide the load shedding level and process. Once a new steady-state is reached, the second stage is activated, which performs load shedding according to the priorities of loads...

  14. A coupled nuclear reactor thermal energy storage system for enhanced load following operation

    International Nuclear Information System (INIS)

    Alameri, Saeed A.; King, Jeffrey C.

    2013-01-01

    Nuclear power plants operate most economically at a constant power level, providing base load electric power. In an energy grid containing a high fraction of renewable power sources, nuclear reactors may be subject to significantly variable power demands. These variable power demands can negatively impact the effective capacity factor of the reactor and result in severe economic penalties. Coupling a nuclear reactor to a large thermal energy storage block will allow the reactor to better respond to variable power demands. In the system described in this paper, a Prismatic core Advanced High Temperature Reactor supplies constant power to a lithium chloride molten salt thermal energy storage block that provides thermal power as needed to a closed Brayton cycle energy conversion system. During normal operation, the thermal energy storage block stores thermal energy during the night for use in the times of peak demand during the day. In this case, the nuclear reactor stays at a constant thermal power level. After a loss of forced circulation, the reactor reaches a shut down state in less than half an hour and the average fuel, graphite and coolant temperatures remain well within the design limits over the duration of the transient, demonstrating the inherent safety of the coupled system. (author)

  15. A dynamic switching strategy for air-conditioning systems operated in light-thermal-load conditions

    International Nuclear Information System (INIS)

    Lin, Jin-Long; Yeh, T.-J.; Hwang, Wei-Yang

    2009-01-01

    Recently, modern air-conditioners have begun to incorporate variable-speed compressors and variable-opening expansion valves, together with feedback control to improve the performance and energy efficiency. However, for the compressor there usually exists a low-speed limit below which its speed can not be continuously modulated unless it is completely turned off. When the air-conditioning system is operated in light-thermal-load conditions, the low-speed limit causes the compressor to run in an on-off manner which can significantly degrade the performance and efficiency. In this paper, a dynamic switching strategy is proposed for such scenarios. The strategy is basically an integration of a cascading control structure, an intuitive switching strategy, and a dynamic compensator. While the control structure provides the nominal performance, the intuitive switching strategy and the dynamic compensator together can account for the compressor's low-speed limitation. Theoretical analysis reveals that when the output matrix of the dynamic compensator is chosen properly, the proposed strategy can effectively reduce the output error caused by the on-off operation of the compressor. Experiments also demonstrate that the proposed strategy can simultaneously provide better regulation for the indoor temperature and improve the energy efficiency at steady state.

  16. Impact of Plasmapheresis on the Time Course of Changes in Cytokines After Operations on the Heart and Great Vessels

    Directory of Open Access Journals (Sweden)

    A. A. Yeremenko

    2005-01-01

    Full Text Available Objective. To assess the impact of plasmapheresis on the time course of changes in pro- and anti-inflammatory interleukins and the results of treatment in patients after complicated operations on the heart and great vessels.Material and methods. 44 patients were examined. In 33 patients, the intra- and postoperative period was complicated by a prolonged extracorporeal circulation (EC, massive blood loss, acute hemolysis, the development of disseminated intravascular coagulation. The above complications gave grounds to perform plasmapheresis (PA in different postoperative periods. The patients were equally divided into 4 groups (each containing 11 patients: 1 patients with multiple organ dysfunction (MOD, in whom PA was conducted within 2—6 hours after surgery; 2 those without MOD, in whom PA was also performed within 2—6 hours after surgery; 3 those with MOD in whom PA was made 16-20 hours after surgery; 4 a control group (receiving no PA, the early postoperative period was normal. Interleukins (IL 6, 8, and 10 and the oxygenation index (OI after surgery and in the first 24 postoperative hours, the duration of EC, the volume of blood loss, and a postoperative clinical period were studied.Results. The duration of EC was highest in Group 1 patients and 37 and 130% greater in Groups 2 and 3, respectively. The elevated levels of IL-6 were noted in all the patients. In the early post-PA periods, the content of IL-6 was decreased by 30% in Groups 1 and 2 patients. In Group 3, the level of IL-6 remained unchanged within the first 24 hours. The postoperative concentration of IL-8 was increased in all the patients. There were no changes in the content of IL-8 after surgery and within the first 12 hours. In Group 3 patients, the level of IL-8 within the first 24 hours was 5 times higher than that observed just after surgery. In patients with developed MOD, a correlation was found between IL-8 and OI postoperatively and within the first 24 hours after

  17. An integrated CAD/CAM system for CNG pressure vessel manufactured by deep drawing and ironing operation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joon Hong; Kim, Chul; Choi, Jae Chan [Pusan National Univ., Pusan (Korea, Republic of)

    2004-06-01

    The fiber reinforced composite material is widely used in the multi-industrial field because of their high specific modulus and specific strength. It has two main merits which are to cut down energy by reducing weight and to prevent explosive damage proceeding to the sudden bursting which is generated by the pressure leakage condition. Therefore, pressure vessels using this composite material can be applied in the field such as defence industry and aerospace industry. In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding of composite vessel subjected to internal pressure, the standard interpretation model is developed by using the ANSYS with AutoLISP and ANSYS APDL languages, general commercial software, which is verified as useful characteristic of the solution. Among the modules of the system, both the process planning module for carrying out the process planning of filament wound composite pressure vessel and the autofrettage process module for obtaining higher residual stress will minimize trial and error and reduce the period for developing new products. The system can serve as a valuable system for experts and as a dependable training aid for beginners.

  18. An integrated CAD/CAM system for CNG pressure vessel manufactured by deep drawing and ironing operation

    International Nuclear Information System (INIS)

    Park, Joon Hong; Kim, Chul; Choi, Jae Chan

    2004-01-01

    The fiber reinforced composite material is widely used in the multi-industrial field because of their high specific modulus and specific strength. It has two main merits which are to cut down energy by reducing weight and to prevent explosive damage proceeding to the sudden bursting which is generated by the pressure leakage condition. Therefore, pressure vessels using this composite material can be applied in the field such as defence industry and aerospace industry. In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding of composite vessel subjected to internal pressure, the standard interpretation model is developed by using the ANSYS with AutoLISP and ANSYS APDL languages, general commercial software, which is verified as useful characteristic of the solution. Among the modules of the system, both the process planning module for carrying out the process planning of filament wound composite pressure vessel and the autofrettage process module for obtaining higher residual stress will minimize trial and error and reduce the period for developing new products. The system can serve as a valuable system for experts and as a dependable training aid for beginners

  19. Robust feedback-linearization control for axial power distribution in pressurized water reactors during load-following operation

    OpenAIRE

    M. Zaidabadi nejad; G.R. Ansarifar

    2018-01-01

    Improved load-following capability is one of the most important technical tasks of a pressurized water reactor. Controlling the nuclear reactor core during load-following operation leads to some difficulties. These difficulties mainly arise from nuclear reactor core limitations in local power peaking: the core is subjected to sharp and large variation of local power density during transients. Axial offset (AO) is the parameter usually used to represent the core power peaking. One of the impor...

  20. Measurement of peak impact loads differ between accelerometers - Effects of system operating range and sampling rate.

    Science.gov (United States)

    Ziebart, Christina; Giangregorio, Lora M; Gibbs, Jenna C; Levine, Iris C; Tung, James; Laing, Andrew C

    2017-06-14

    A wide variety of accelerometer systems, with differing sensor characteristics, are used to detect impact loading during physical activities. The study examined the effects of system characteristics on measured peak impact loading during a variety of activities by comparing outputs from three separate accelerometer systems, and by assessing the influence of simulated reductions in operating range and sampling rate. Twelve healthy young adults performed seven tasks (vertical jump, box drop, heel drop, and bilateral single leg and lateral jumps) while simultaneously wearing three tri-axial accelerometers including a criterion standard laboratory-grade unit (Endevco 7267A) and two systems primarily used for activity-monitoring (ActiGraph GT3X+, GCDC X6-2mini). Peak acceleration (gmax) was compared across accelerometers, and errors resulting from down-sampling (from 640 to 100Hz) and range-limiting (to ±6g) the criterion standard output were characterized. The Actigraph activity-monitoring accelerometer underestimated gmax by an average of 30.2%; underestimation by the X6-2mini was not significant. Underestimation error was greater for tasks with greater impact magnitudes. gmax was underestimated when the criterion standard signal was down-sampled (by an average of 11%), range limited (by 11%), and by combined down-sampling and range-limiting (by 18%). These effects explained 89% of the variance in gmax error for the Actigraph system. This study illustrates that both the type and intensity of activity should be considered when selecting an accelerometer for characterizing impact events. In addition, caution may be warranted when comparing impact magnitudes from studies that use different accelerometers, and when comparing accelerometer outputs to osteogenic impact thresholds proposed in literature. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  1. Automation-aided Task Loads Index based on the Automation Rate Reflecting the Effects on Human Operators in NPPs

    International Nuclear Information System (INIS)

    Lee, Seungmin; Seong, Poonghyun; Kim, Jonghyun

    2013-01-01

    Many researchers have found that a high automation rate does not guarantee high performance. Therefore, to reflect the effects of automation on human performance, a new estimation method of the automation rate that considers the effects of automation on human operators in nuclear power plants (NPPs) was suggested. These suggested measures express how much automation support human operators but it cannot express the change of human operators' workload, whether the human operators' workload is increased or decreased. Before considering automation rates, whether the adopted automation is good or bad might be estimated in advance. In this study, to estimate the appropriateness of automation according to the change of the human operators' task loads, automation-aided task loads index is suggested based on the concept of the suggested automation rate. To insure plant safety and efficiency on behalf of human operators, various automation systems have been installed in NPPs, and many works which were previously conducted by human operators can now be supported by computer-based operator aids. According to the characteristics of the automation types, the estimation method of the system automation and the cognitive automation rate were suggested. The proposed estimation method concentrates on the effects of introducing automation, so it directly express how much the automated system support human operators. Based on the suggested automation rates, the way to estimate how much the automated system can affect the human operators' cognitive task load is suggested in this study. When there is no automation, the calculated index is 1, and it means there is no change of human operators' task load

  2. Automation-aided Task Loads Index based on the Automation Rate Reflecting the Effects on Human Operators in NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seungmin; Seong, Poonghyun [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Kim, Jonghyun [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2013-05-15

    Many researchers have found that a high automation rate does not guarantee high performance. Therefore, to reflect the effects of automation on human performance, a new estimation method of the automation rate that considers the effects of automation on human operators in nuclear power plants (NPPs) was suggested. These suggested measures express how much automation support human operators but it cannot express the change of human operators' workload, whether the human operators' workload is increased or decreased. Before considering automation rates, whether the adopted automation is good or bad might be estimated in advance. In this study, to estimate the appropriateness of automation according to the change of the human operators' task loads, automation-aided task loads index is suggested based on the concept of the suggested automation rate. To insure plant safety and efficiency on behalf of human operators, various automation systems have been installed in NPPs, and many works which were previously conducted by human operators can now be supported by computer-based operator aids. According to the characteristics of the automation types, the estimation method of the system automation and the cognitive automation rate were suggested. The proposed estimation method concentrates on the effects of introducing automation, so it directly express how much the automated system support human operators. Based on the suggested automation rates, the way to estimate how much the automated system can affect the human operators' cognitive task load is suggested in this study. When there is no automation, the calculated index is 1, and it means there is no change of human operators' task load.

  3. ANALYSIS OF ENERGY EFFICIENCY OF OPERATING MODES OF ELECTRICAL SYSTEMS WITH THE TRACTION LOADS

    Directory of Open Access Journals (Sweden)

    V. E. Bondarenko

    2017-03-01

    account operation mode of power systems and the use of software systems with imitation of instantaneous interrelated schemes of transport loads.

  4. 46 CFR 4.03-40 - Public vessels.

    Science.gov (United States)

    2010-10-01

    ... INVESTIGATIONS Definitions § 4.03-40 Public vessels. Public vessel means a vessel that— (a) Is owned, or demise... Department (except a vessel operated by the Coast Guard or Saint Lawrence Seaway Development Corporation...

  5. Umbilical Cable Recovery Load Analysis

    Institute of Scientific and Technical Information of China (English)

    YAN Shu-wang; JIA Zhao-lin; FENG Xiao-wei; LI Shi-tao

    2013-01-01

    Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field.The severe ocean environment makes great challenges to umbilical maintenance and repair work.Damaged umbilical is usually recovered for the regular operation of the offshore production system.Analysis on cables in essence is a two-point boundary problem.The tension load at the mudline must be known first,and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation.The recovery analysis also involves umbilicalsoil interaction and becomes more complicated.Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed.The analysis results provide a theoretical reference for offshore on-deck operation.

  6. Crack behaviour of ferritic pressure vessels steels in oxygenated high temperature water under transient loadings. Crack corrosion phase 2. Crack development and fatigue. Final report

    International Nuclear Information System (INIS)

    Weissenberg, Thomas

    2014-03-01

    Using the example of the ferritic steels 22NiMoCr3-7 and 15MnNi6-3 representative for Nuclear Power Plants experimental data for the evaluation of the influence of the light water reactor (LWR) coolant environment and postulated chloride contaminations on crack development and fatigue have been determined in order to verify and extend the basis for a reliable estimation of the residual service life of reactor components. The aim of the research project was the investigation of the environmental effects at low strain rate conditions and the determination of the fatigue life under cyclic loading at uniaxial and multiaxial stress state. The quasi-static tensile tests (Constant Extension Rate Test, CERT) were performed using 3 low strain rates, each differing by about one order of magnitude (2.5.10 -3 , 3.1.10 -4 and 2.3.10 -5 %/s). The low cycle fatigue (LCF) experiments were conducted applying alternating tensile-compression loading with strain amplitudes of 0.3, 0.5 and 0.9 % at strain rates of 0.1 and 0.01 %/s (tests in air primarily 0.1 %/s). The cyclic notched tensile tests were carried out with a nominal axial strain in the notch root of 0.5 % at a strain rate of 0.1 %/s. The experiments in each case were performed in air, high purity water and chloride containing water at a testing temperature of 240 C, the oxygen content of the liquid medium was set to 0.4 ppm (simulated boiling water reactor coolant). In the CERT experiments chloride contents of 30, 50 and 100 ppb were applied, in the LCF tests the chloride content was 50 ppb which can be regarded as an upper realistic limit for a postulated chloride contamination of the reactor coolant. All experiments in liquid environment were preceded by a pre-autoclaving phase of at least 100 h in order to allow the formation of a stable oxide layer (magnetite). The testing material 22NiMoCr3-7 was available in form of an original reactor pressure vessel shell primarily designated for the German nuclear power plant

  7. Tribological Evaluation of Candidate Gear Materials Operating Under Light Loads in Highly Humid Conditions

    Science.gov (United States)

    Dellacorte, Christopher; Thomas, Fransua; Leak, Olivia Ann

    2015-01-01

    A series of pin-on-disk sliding wear tests were undertaken to identify candidate materials for a pair of lightly loaded timing gears operating under highly humid conditions. The target application involves water purification and thus precludes the use of oil, grease and potentially toxic solid lubricants. The baseline sliding pair is austenitic stainless steel operating against a carbon filled polyimide. The test load and sliding speed (4.9 N, 2.7 m/s) were chosen to represent average contact conditions of the meshing gear teeth. In addition to the baseline materials, the hard superelastic NiTiNOL 60 (60NiTi) was slid against itself, against the baseline polyimide, and against 60NiTi onto which a commercially deposited dry film lubricant (DFL) was applied. The alternate materials were evaluated as potential replacements to achieve a longer wear life and improved dimensional stability for the timing gear application. An attempt was also made to provide solid lubrication to self-mated 60NiTi by rubbing the polyimide against the disk wear track outside the primary 60NiTi-60NiTi contact, a method named stick or transfer-film lubrication. The selected test conditions gave repeatable friction and wear data and smooth sliding surfaces for the baseline materials similar to those in the target application. Friction and wear for self-mated stainless steel were high and erratic. Self-mated 60NiTi gave acceptably low friction (approx. 0.2) and modest wear but the sliding surfaces were rough and potentially unsuitable for the gear application. Tests in which 60NiTi pins were slid against DFL coated 60NiTi and DFL coated stainless steel gave low friction and long wear life. The use of stick lubrication via the secondary polyimide pin provided effective transfer film lubrication to self-mated 60NiTi tribological specimens. Using this approach, friction levels were equal or lower than the baseline polyimide-stainless combination and wear was higher but within data scatter observed

  8. Revisiting the reactor pressure vessel for long-time operation; Revisitando la vasija a presion del reactor para largos tiempos de operacion

    Energy Technology Data Exchange (ETDEWEB)

    Lapena, J.; Serrano, M.; Diego, G. de; Hernandez Mayoral, M.

    2013-07-01

    The reactor pressure vessel (RPV) is one of the key components of nuclear power plants, especially for long time operation. It is a non-replaceable component, at least with current technology. the structural integrity of the vessel is evaluated within called monitoring programs where the degradation of the mechanical properties due to neutron irradiation is determined. From the first designs of the RPVs and monitoring programs in the years 60-70 currently still in force, there have been major advances in the understanding of radiation damage and methods of evaluation. Thus, it is recommended the use of forgings instead of plates in the construction of the RPVs in order to reduce the number of welds, more sensitive to neutron irradiation, and using starting materials with less content of impurities, particularly copper. To evaluate the embrittlement of RPVs the Master Curve methodology is currently used, through the testing of the charpy specimens from the surveillance capsules, to determine the fracture toughness. This article summarizes the last activities of CIEMAT into the European research projects LONGIFFE and PERFORM60, about the knowledge of radiation damage in materials with low copper content, traditionally considered less sensitive to irradiation, and the use of the Master Curve in advanced surveillance programs. The activities related to the problems associated with the use of large forging, such as the appearance of hydrogen flakes in the vessel of Doel 3, and its implications, are also presented. (Author)

  9. Optimization for steady-state and hybrid operations of ITER by using scaling models of divertor heat load

    International Nuclear Information System (INIS)

    Murakami, Yoshiki; Itami, Kiyoshi; Sugihara, Masayoshi; Fujieda, Hirobumi.

    1992-09-01

    Steady-state and hybrid mode operations of ITER are investigated by 0-D power balance calculations assuming no radiation and charge-exchange cooling in divertor region. Operation points are optimized with respect to divertor heat load which must be reduced to the level of ignition mode (∼5 MW/m 2 ). Dependence of the divertor heat load on the variety of the models, i.e., constant-χ model, Bohm-type-χ model and JT-60U empirical scaling model, is also discussed. The divertor heat load increases linearly with the fusion power (P FUS ) in all models. The possible highest fusion power much differs for each model with an allowable divertor heat load. The heat load evaluated by constant-χ model is, for example, about 1.8 times larger than that by Bohm-type-χ model at P FUS = 750 MW. Effect of reduction of the helium accumulation, improvements of the confinement capability and the current-drive efficiency are also investigated aiming at lowering the divertor heat load. It is found that NBI power should be larger than about 60 MW to obtain a burn time longer than 2000 s. The optimized operation point, where the minimum divertor heat load is achieved, does not depend on the model and is the point with the minimum-P FUS and the maximum-P NBI . When P FUS = 690 MW and P NBI = 110 MW, the divertor heat load can be reduced to the level of ignition mode without impurity seeding if H = 2.2 is achieved. Controllability of the current-profile is also discussed. (J.P.N.)

  10. Thermal structural analysis of SST-1 vacuum vessel and cryostat assembly using ANSYS

    International Nuclear Information System (INIS)

    Santra, Prosenjit; Bedakihale, Vijay; Ranganath, Tata

    2009-01-01

    Steady state super-conducting tokamak-1 (SST-1) is a medium sized tokamak, which has been designed to produce a 'D' shaped double null divertor plasma and operate in quasi steady state (1000 s). SST-1 vacuum system comprises of plasma chamber (vacuum vessel, interconnecting rings, baking and cooling channels), and cryostat all made of SS 304L material designed to meet ultra high vacuum requirements for plasma generation and confinement. Prior to plasma shot and operation the vessel assembly is baked to 250/150 deg. C from room temperature and discharge cleaned to remove impurities/trapped gases from wall surfaces. Due to baking the non-uniform temperature pattern on the vessel assembly coupled with atmospheric pressure loading and self-weight give rise to high thermal-structural stresses, which needs to be analyzed in detail. In addition the vessel assembly being a thin shell vessel structure needs to be checked for critical buckling load caused by atmospheric and baking thermal loads. Considering symmetry of SST-1, 1/16th of the geometry is modeled for finite element (FE) analysis using ANSYS for different loading scenarios, e.g. self-weight, pressure loading considering normal operating conditions, and off-normal loads coupled with baking of vacuum vessel from room temperature 250 deg. C to 150 deg. C, buckling and modal analysis for future dynamic analysis. The paper will discuss details about SST-1 vacuum system/cryostat, solid and FE model of SST-1, different loading scenarios, material details and the stress codes used. We will also present the thermal structural results of FE analysis using ANSYS for various load cases being investigated and our observations under different loading conditions.

  11. Impact of load follow operation on the chemistry of the primary and secondary circuit of a pressurized water reactor

    International Nuclear Information System (INIS)

    Boettcher, F.; Riehm, S.; Bolz, M.; Speck, A.

    2012-09-01

    Germany decided to abandon nuclear energy and to switch to renewable energy forms. According the renewable energy act renewable energy forms have priority to be fed to the grid. The support of wind and solar energy demands more and more load follow operation of the remaining nuclear power plants to stabilize the grid. This report summarizes first experience with load follow operation in two pressurized water reactors (Philippsburg KKP2 and Neckarwestheim GKNI) with regard to chemistry and radiology. The most important mechanisms of dose rate built up on the primary side are described with Co-60 and Co-58 being the main contributors to dose rate. Goal of the primary side chemistry is to avoid or at least to delay the dose rate built-up as far as achievable. Both reactors are operated according to the modified coordinated B-Li-Chemistry with a pH300 of 7.4 as target value for optimised dose build up delay. By using B-10-enriched boric acid with a boron-10 abundance of 30 at-% (compared to ca. 19.9 at-% in natural boron) the pH 300 target value can be reached earlier in the cycle due to the lower concentration of boric acid required for neutron balancing. In GKNI Zn-injection was started 2005 as a mean of dose reduction. Since 2007 GKNI was operated with load follow operation. In KKP2 load reductions due to wind energy excess are more and more common since 2008. The results of dose rate measurements on the primary side are correlated to primary coolant chemistry and load follow operation. The use of enriched boric acid had a positive (i.e. reducing dose rate) impact on the activity build-up of Co-60 on the loop lines, thus proving the effectiveness of the VGB specifications. After 5 years (one half life time of Co-60) of Zn-injection a positive effect on surface occupancy with nuclides can be determined. The impact of short term deviations from optimal chemical conditions during load follow operation on the activity build up is assessed on the basis of the corrosion

  12. Modification of the axial offsets trajectory method to control xenon oscillation during load following operations

    International Nuclear Information System (INIS)

    Shimazu, Yoichiro

    1996-01-01

    A new method which can give continuous guidance for controlling axial xenon oscillations in large PWRs has been presented. The method is based on two additional newly defined axial offsets, A Oi and A Ox together with the conventional axial offset of power distribution A Op. A Oi and A Ox are the axial offsets of power distributions which would give the current iodine and xenon distributions under equilibrium conditions, respectively. The information from A Oi, A Ox and A Op are used to display the trajectory of (A Op - A Ox, A Oi - A Ox) in the X-Y plane. The trajectory shows a very characteristic behavior. With the characteristics in mind the xenon oscillation can be controlled quite easily to lead the plot to the origin where three A Os are identical. The method has been proved with the power level constant. However, it is necessary to modify the definition of A Ox so as to apply this method to load following operations. A reasonable way of the modification is described and the results are presented. (author)

  13. Dynamics of the Energy Transfer to the Load During the Operation of a Plasma Opening Switch

    International Nuclear Information System (INIS)

    Dolinsky, Yu.; Krasik, Ya.E.; Felsteiner, J.

    1999-01-01

    The main efforts of the theoretical and experimental studies related to the Plasma Opening Switch (POS) have been devoted to the understanding of an anomalous fast magnetic field penetration through the plasma. At present this phenomenon can be explained based on the electron magnetohydrodynamic theory.l The second important phenomenon is related with POS opening. Existing models explain POS opening as a result of cut-off of the electron current component in the double layer2 by self-magnetic field of the POS current or by the increase of the Hall potential in the current layer due to ion erosion.3 Nevertheless both models consider POS opening in the region which was preliminary occupied by the plasma. In a recent experiment4 it was shown that the POS opening is related with a fast charged particle flow in the downstream region, namely at the load. In this work we present results of theoretical studies of the phase of the POS operation when the self-magnetic field of the POS current appears at the downstream side of the plasma. Our study has been done within the framework of two-fluid magnetohydrodynamic theory. Taking into account the Hall electric field which is responsible for a strong ion acceleration in the axial direction, we found the velocity of the ions. In addition we show, that due to the inductive electric field caused by the motion of the axial current carrying plasma, the velocity of the magnetic field penetration is equal to the Alfven velocity

  14. Dynamic Analysis of Load Operations of Two-Stage SOFC Stacks Power Generation System

    Directory of Open Access Journals (Sweden)

    Paulina Pianko-Oprych

    2017-12-01

    Full Text Available The main purpose of this paper was to develop a complete dynamic model of a power generation system based on two serially connected solid oxide fuel cell stacks. The uniqueness of this study lies in a different number of fuel cells in the stacks. The model consists of the electrochemical model, mass and energy balance equations implemented in MATLAB Simulink environment. Particular attention has been paid to the analysis of the transient response of the reformers, fuel cells and the burner. The dynamic behavior of the system during transient conditions was investigated by load step changing. The model evaluates electrical and thermal responses of the system at variable drawn current. It was found that a decrease of 40% in the 1st stage and 2nd solid oxide fuel cell (SOFC stacks drawn current caused both stacks temperature to drop by 2%. An increase of the cell voltage for the 1st and 2nd SOFC stacks led to very fast steam reformer response combined with a slight decrease in reformer temperature, while a considerable burner temperature increase of 70 K can be observed. Predictions of the model provide the basic insight into the operation of the power generation-based SOFC system during various transients and support its further design modifications.

  15. Optimization of steam generators of NPP with WWER in operation with variable load

    Science.gov (United States)

    Parchevskii, V. M.; Shchederkina, T. E.; Gur'yanova, V. V.

    2017-11-01

    The report addresses the issue of the optimal water level in the horizontal steam generators of NPP with WWER. On the one hand, the level needs to be kept at the lower limit of the allowable range, as gravity separation, steam will have the least humidity and the turbine will operate with higher efficiency. On the other hand, the higher the level, the greater the supply of water in the steam generator, and therefore the higher the security level of the unit, because when accidents involving loss of cooling of the reactor core, the water in the steam generators, can be used for cooling. To quantitatively compare the damage from higher level to the benefit of improving the safety was assessed of the cost of one cubic meter of water in the steam generators, the formulated objective function of optimal levels control. This was used two-dimensional separation characteristics of steam generators. It is demonstrated that the security significantly shifts the optimal values of the levels toward the higher values, and this bias is greater the lower the load unit.

  16. Power system operation risk analysis considering charging load self-management of plug-in hybrid electric vehicles

    International Nuclear Information System (INIS)

    Liu, Zhe; Wang, Dan; Jia, Hongjie; Djilali, Ned

    2014-01-01

    Highlights: • The interactive mechanism between system and PHEVs is presented. • The charging load self-management without sacrificing user requirements is proposed. • The charging load self-management is coupled to system operation risk analysis. • The charging load self-management can reduce the extra risk brought by PHEVs. • The charging load self-management can shift charging power to the time with low risk. - Abstract: Many jurisdictions around the world are supporting the adoption of electric vehicles through incentives and the deployment of a charging infrastructure to reduce greenhouse gas emissions. Plug-in hybrid electric vehicles (PHEVs), with offer mature technology and stable performance, are expected to gain an increasingly larger share of the consumer market. The aggregated effect on power grid due to large-scale penetration of PHEVs needs to be analyzed. Nighttime-charging which typically characterizes PHEVs is helpful in filling the nocturnal load valley, but random charging of large PHEV fleets at night may result in new load peaks and valleys. Active response strategy is a potentially effective solution to mitigate the additional risks brought by the integration of PHEVs. This paper proposes a power system operation risk analysis framework in which charging load self-management is used to control system operation risk. We describe an interactive mechanism between the system and PHEVs in conjunction with a smart charging model is to simulate the time series power consumption of PHEVs. The charging load is managed with adjusting the state transition boundaries and without violating the users’ desired charging constraints. The load curtailment caused by voltage or power flow violation after outages is determined by controlling charging power. At the same time, the system risk is maintained under an acceptable level through charging load self-management. The proposed method is implemented using the Roy Billinton Test System (RBTS) and

  17. LOAD FORECASTING FOR POWER SYSTEM PLANNING AND OPERATION USING ARTIFICIAL NEURAL NETWORK AT AL BATINAH REGION OMAN

    Directory of Open Access Journals (Sweden)

    HUSSEIN A. ABDULQADER

    2012-08-01

    Full Text Available Load forecasting is essential part for the power system planning and operation. In this paper the modeling and design of artificial neural network for load forecasting is carried out in a particular region of Oman. Neural network approach helps to reduce the problem associated with conventional method and has the advantage of learning directly from the historical data. The neural network here uses data such as past load; weather information like humidity and temperatures. Once the neural network is trained for the past set of data it can give a prediction of future load. This reduces the capital investment reducing the equipments to be installed. The actual data are taken from the Mazoon Electrical Company, Oman. The data of load for the year 2007, 2008 and 2009 are collected for a particular region called Al Batinah in Oman and trained using neural networks to forecast the future. The main objective is to forecast the amount of electricity needed for better load distribution in the areas of this region in Oman. The load forecasting is done for the year 2010 and is validated for the accuracy.

  18. Nuclear piping and pipe support design and operability relating to loadings and small bore piping

    International Nuclear Information System (INIS)

    Stout, D.H.; Tubbs, J.M.; Callaway, W.O.; Tang, H.T.; Van Duyne, D.A.

    1994-01-01

    The present nuclear piping system design practices for loadings, multiple support design and small bore piping evaluation are overly conservative. The paper discusses the results developed for realistic definitions of loadings and loading combinations with methodology for combining loads under various conditions for supports and multiple support design. The paper also discusses a simplified method developed for performing deadweight and thermal evaluations of small bore piping systems. Although the simplified method is oriented towards the qualification of piping in older plants, this approach is applicable to plants designed to any edition of the ASME Section III or B31.1 piping codes

  19. Tempest in a vessel

    International Nuclear Information System (INIS)

    Barre, Bertrand

    2015-01-01

    As the ASN made some statements about anomalies of carbon content in the EPR vessel bottom and top, the author recalls and comments some technical issues to better understand the information published on this topic. He notably addresses the role of the vessel, briefly indicates its operating conditions, shape and structure, and mechanical components for the top, its material and mechanical properties, and test samples used to assess mechanical properties. He also comments the phenomenon of radio-induced embrittlement, the vessel manufacturing process, and evokes the applicable regulations. He quotes and comments statements made by the ASN and Areva which evoke further assessments of the concerned components

  20. Loading/unloading buoy. Laste/lossebye

    Energy Technology Data Exchange (ETDEWEB)

    Breivik, K.; Smedal, A.; Syvertsen, K.

    1994-07-04

    The invention relates to a buoy for use in loading or unloading of a flowable medium, especially oil. The buoy is at its lower end arranged for connection to at least one transfer line and further being arranged to be introduced into a submerged downwardly open receiving space in a floating vessel. The buoy forms in operation a transfer connection between the transfer line and a tube system on the vessel. The buoy comprises an outer buoyancy member arranged for releasable locking to the receiving space of the vessel by means of a locking mechanism arranged therein, and centrally in the outer member a rotatably mounted member which forms a passage for medium and at its ends is arranged for connection to the transfer line and the tube system on the vessel, respectively. The buoy at its upper end is connected to a means for hoisting and introducing the buoy into the receiving space of the vessel. 8 figs.

  1. Operative correction of judoists’ training loads on the base of on-line monitoring of heart beats rate

    Directory of Open Access Journals (Sweden)

    Yong Qiang Liu

    2015-04-01

    Full Text Available Purpose: ensure increase of effectiveness of training process’s control by means of operative correction of training loads of different qualification judo wrestlers’ heart beats rate indicators. Material: the research was conducted on the base of Brest SCJSOR № 1. Judo wrestlers of different sport qualification (age 17-19 years old, n=15 participated in the research. Monitoring of judo wrestlers’ heart beats rate was carried out with the help of system “Polar”. Results: we have found factorial structure of functional fitness in every profile of sportsmen. Model characteristics of judo wrestlers were supplemented with the most important sides of functional fitness. Analysis of indicators of restoration effectiveness indicators (REI in both groups of judo wrestlers showed high level of organism’s responsiveness to training load of special and power orientation in comparison with speed power load. We have worked out algorithm of operative correction of training loads by indicators of heart beats rate in training process, depending on orientation and intensity of loads’ physiological influence on judo wrestler. Conclusions: Telemetric on-line monitoring of sportsman’s heart beats rate and calculation of REI permit to objectively assess effectiveness of training’s construction and of micro-cycle in total and detect in due time the trend to development of over-loading and failure of adaptation.

  2. Operative correction of judoists’ training loads on the base of on-line monitoring of heart beats rate

    Directory of Open Access Journals (Sweden)

    Liu Yong Qiang

    2015-02-01

    Full Text Available Purpose: ensure increase of effectiveness of training process’s control by means of operative correction of training loads of different qualification judo wrestlers’ heart beats rate indicators. Material: the research was conducted on the base of Brest SCJSOR № 1. Judo wrestlers of different sport qualification (age 17-19 years old, n=15 participated in the research. Monitoring of judo wrestlers’ heart beats rate was carried out with the help of system “Polar”. Results: we have found factorial structure of functional fitness in every profile of sportsmen. Model characteristics of judo wrestlers were supplemented with the most important sides of functional fitness. Analysis of indicators of restoration effectiveness indicators (REI in both groups of judo wrestlers showed high level of organism’s responsiveness to training load of special and power orientation in comparison with speed power load. We have worked out algorithm of operative correction of training loads by indicators of heart beats rate in training process, depending on orientation and intensity of loads’ physiological influence on judo wrestler. Conclusions: Telemetric on-line monitoring of sportsman’s heart beats rate and calculation of REI permit to objectively assess effectiveness of training’s construction and of micro-cycle in total and detect in due time the trend to development of over-loading and failure of adaptation.

  3. Research program plan: reactor vessels. Volume 1

    International Nuclear Information System (INIS)

    Vagins, M.; Taboada, A.

    1985-07-01

    The ability of the licensing staff of the NRC to make decisions concerning the present and continuing safety of nuclear reactor pressure vessels under both normal and abnormal operating conditions is dependent upon the existence of verified analysis methods and a solid background of applicable experimental data. It is the role of this program to provide both the analytical methods and the experimental data needed. Specifically, this program develops fracture mechanics analysis methods and design criteria for predicting the stress levels and flaw sizes required for crack initiation, propagation, and arrest in LWR pressure vessels under all known and postulated operations conditions. To do this, not only must the methods be developed but they must be experimentally validated. Further, the materials data necessary for input to these analytical methods must be developed. Thus, in addition to methods development and large scale experimental verification this program also develops data to show that slow-load fracture toughness, rapid-load fracture toughness, and crack arrest toughness obtained from small laboratory specimens are truly representative of the toughness characteristics of the material behavior in pressure vessels in both the unirradiated and the irradiated conditions

  4. Load kick-back effects due to activation of demand response in view of distribution grid operation

    DEFF Research Database (Denmark)

    Han, Xue; Sossan, Fabrizio; Bindner, Henrik W.

    2014-01-01

    . The paper has shown how aggregated consumption dynamics introduce new peaks in the system due to the synchronous behaviors of a portfolio of homogeneous DSRs, which is instructed by the flexibility management system. This dynamic effect is recognized as load kick-back effect. The impact of load kick......-back effects onto the distribution grid is analysed in this paper by establishing scenarios based on the estimation of DSR penetration levels from the system operator. The results indicate some risks that the activation of demand response may create critical peaks in the local grid due to kick-back effects....

  5. A knowledge-based system for control of xenon-induced spatial power oscillations during load-follow operations

    International Nuclear Information System (INIS)

    Chung, Sun-Kyo; Danofsky, R.A.; Spinrad, B.I.

    1988-01-01

    As is well known, large pressurized water reactors (PWRs) are subject to xenon-induced axial power oscillations at some time during a given cycle. Attention to this behavior is required during load-follow operations. A knowledge-based system for controlling xenon-induced spatial power oscillations is described. Experience with a limited set of load-follow patterns has demonstrated that the system is capable of providing advice on appropriate control actions. A simulation model, coupled with a rule-learning process, has been found to be a useful way for determining appropriate weights for the rules that relate power patterns and control actions

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

    DEFF Research Database (Denmark)

    Ma, Ke; Blaabjerg, Frede; Liserre, Marco

    2012-01-01

    In order to fulfill the continuous growing grid-side demands, the full-scale power converters are becoming more and more popular in the wind power application. Nevertheless, the more severe loading of the power semiconductor devices in the full-scale power converters, especially during Low Voltage...... Ride Through (LVRT) operation under grid faults, may compromise the reliability of the system and consequently further increase its cost. In this paper, the impact of various grid faults on a three-level Neutral-Point-Clamped (3L-NPC) grid-converter in terms of thermal loading of power semiconductor...

  7. Sliding Mode Control for Pressurized-Water Nuclear Reactors in load following operations with bounded xenon oscillations

    International Nuclear Information System (INIS)

    Ansarifar, G.R.; Saadatzi, S.

    2015-01-01

    Highlights: • We present SMC which is a robust nonlinear controller to control the PWR power. • Xenon oscillations are kept bounded within acceptable limits. • The stability analysis has been based on Lyapunov approach. • Simulation results indicate the high performance of this new control. - Abstract: One of the important operations in nuclear power plants is load-following in which imbalance of axial power distribution induces xenon oscillations. These oscillations must be maintained within acceptable limits otherwise the nuclear power plant could become unstable. Therefore, bounded xenon oscillation considered to be a constraint for the load-following operation. In this paper, sliding mode control (SMC) which is a robust nonlinear controller is designed to control the Pressurized-Water Nuclear Reactor (PWR) power for the load-following operation problem that ensures xenon oscillations are kept bounded within acceptable limits. The proposed controller uses constant axial offset (AO) strategy to maintain xenon oscillations to be bounded. The constant AO is a robust state constraint for load-following problem. The reactor core is simulated based on the two-point nuclear reactor model and one delayed neutron group. The stability analysis is given by means Lyapunov approach, thus the control system is guaranteed to be stable within a large range. The employed method is easy to implement in practical applications and moreover, the sliding mode control exhibits the desired dynamic properties during the entire output-tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness and stability. Results show that the proposed controller for the load-following operation is sufficiently effective so that the xenon oscillations are kept bounded in the considered region

  8. Preventive maintenance and load testing of fixed position cranes in support of major operations

    International Nuclear Information System (INIS)

    Detrick, C.K.

    1980-01-01

    This paper will address load testing and preventive maintenance of fixed in-place cranes in general, and maintenance and load testing of the 200 ton Polar Gantry Crane at the FFTF in particular. This paper also covers the installation of a 100-ton bridge crane in the FFTF's Reactor Service Building, as well as use of these cranes in making important lifts of FFTF equipment

  9. On results of tests of thermal insulation structural fragments for in-vessel equipment and pipelines of the VG-400 plant on vibrational and acoustic loads

    International Nuclear Information System (INIS)

    Ledenko, S.A.; Andreev, V.A.; Mirenkov, A.F.; Zakharov, V.A.; Suvorov, V.E.; Prokimnov, V.V.

    1990-01-01

    Results of vibrostrength and acoustic fatigue tests of the fragments of thermal insulation for in-vessel equipment and pipelines of the VG-400 reactor are presented. The insulation structure is based on the insulation layer made of steel foil and carbon materials. Weak points in the insulation structure, namely - the welded joints of stiffening ribs - are detected in the course of testing. A conclusion is made on the possibility of vibrational test substitution for the acoustic ones

  10. Application of ELD and load forecast in optimal operation of industrial boiler plants equipped with thermal stores

    International Nuclear Information System (INIS)

    Cao Jiacong

    2007-01-01

    Optimal operation of industrial boiler plants with objects of high energy efficiency and low fuel cost is still well worth investigating when energy problem becomes a world's concern, for there are a great number of boiler plants serving industries. The optimization of operation is a measure that is less expensive and easier to carry out than many other measures. Economic load dispatch (ELD) is an effective approach to optimal operation of industrial boiler plants. In the paper a newly developed method referred to as the method of minimum-departure model (MDM) is used in the ELD for boiler plants. It is more convenient for carrying out ELD when boiler plants are equipped with thermal energy stores that usually adopt the working mode of optimal segmentation of a daily load curve. In the case of industrial boiler plants, ELD needs a prerequisite, viz., the accurate load forecast, which is performed using artificial neural networks in this paper. A computer program for the optimal operation was completed and applied to an example, which results the minimum daily fuel cost of the whole boiler plant

  11. Field measurement of the piping system vibration of Ko-Ri unit 4 during the load-following operation

    International Nuclear Information System (INIS)

    Chung, Tae-Young; Hong, Sung-Yull; Kim, Bum-Nyun.

    1989-01-01

    During the load-following operation of nuclear power plants, flow rate, temperature, and pressure in the piping system can be varied by changing the electric power output level, and these variations can cause different vibration phenomena in the piping system. The piping system vibration is important because it is directly related to the dynamic stress of the piping system and can affect the life of the piping system through structural fatigue. An assessment of vibration levels for the classes II and III piping systems of the Ko-Ri Unit 4950-MW nuclear power plant was performed according to the given pattern of the load-following operation to study its feasibility from the viewpoint of piping system vibration. The classes II and III piping system vibration of the Ko-Ri Unit 4 may not cause any potential problem under the given pattern of the load-following operation; however, it is recommended that long-term operation in the 85 to 95% power range be avoided as much as possible

  12. Long term operation of continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

    Science.gov (United States)

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-09-01

    In this study, a continuous-flow system with enhanced biological phosphorus removal (EBPR) granules was operated at different COD concentrations (200, 300 and 400mgL(-)(1)) to investigate the effect of COD loading on this system. The results showed that when the COD concentration in influent was increased to 400mgL(-)(1), the anaerobic COD removal efficiency and total phosphorus removal efficiency reduced obviously and the settling ability of granules deteriorated due to the proliferation of filamentous bacteria. Moreover, high COD loading inhibited the EPS secretion and destroyed the stability of granules. Results of high-through pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading. The performance of system, settling ability of granules and proportion of PAOs gradually recovered to the initial level after the COD concentration was reduced to 200mgL(-)(1) on day 81. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Real - time Optimization of Distributed Energy Storage System Operation Strategy Based on Peak Load Shifting

    Science.gov (United States)

    Wang, Qian; Lu, Guangqi; Li, Xiaoyu; Zhang, Yichi; Yun, Zejian; Bian, Di

    2018-01-01

    To take advantage of the energy storage system (ESS) sufficiently, the factors that the service life of the distributed energy storage system (DESS) and the load should be considered when establishing optimization model. To reduce the complexity of the load shifting of DESS in the solution procedure, the loss coefficient and the equal capacity ratio distribution principle were adopted in this paper. Firstly, the model was established considering the constraint conditions of the cycles, depth, power of the charge-discharge of the ESS, the typical daily load curves, as well. Then, dynamic programming method was used to real-time solve the model in which the difference of power Δs, the real-time revised energy storage capacity Sk and the permission error of depth of charge-discharge were introduced to optimize the solution process. The simulation results show that the optimized results was achieved when the load shifting in the load variance was not considered which means the charge-discharge of the energy storage system was not executed. In the meantime, the service life of the ESS would increase.

  14. Wind Energy Management System EMS Integration Project: Incorporating Wind Generation and Load Forecast Uncertainties into Power Grid Operations

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, Yuri V.; Huang, Zhenyu; Etingov, Pavel V.; Ma, Jian; Guttromson, Ross T.; Subbarao, Krishnappa; Chakrabarti, Bhujanga B.

    2010-01-01

    unique features make this work a significant step forward toward the objective of incorporating of wind, solar, load, and other uncertainties into power system operations. Currently, uncertainties associated with wind and load forecasts, as well as uncertainties associated with random generator outages and unexpected disconnection of supply lines, are not taken into account in power grid operation. Thus, operators have little means to weigh the likelihood and magnitude of upcoming events of power imbalance. In this project, funded by the U.S. Department of Energy (DOE), a framework has been developed for incorporating uncertainties associated with wind and load forecast errors, unpredicted ramps, and forced generation disconnections into the energy management system (EMS) as well as generation dispatch and commitment applications. A new approach to evaluate the uncertainty ranges for the required generation performance envelope including balancing capacity, ramping capability, and ramp duration has been proposed. The approach includes three stages: forecast and actual data acquisition, statistical analysis of retrospective information, and prediction of future grid balancing requirements for specified time horizons and confidence levels. Assessment of the capacity and ramping requirements is performed using a specially developed probabilistic algorithm based on a histogram analysis, incorporating all sources of uncertainties of both continuous (wind and load forecast errors) and discrete (forced generator outages and start-up failures) nature. A new method called the “flying brick” technique has been developed to evaluate the look-ahead required generation performance envelope for the worst case scenario within a user-specified confidence level. A self-validation algorithm has been developed to validate the accuracy of the confidence intervals.

  15. Automatic optimization of core loading patterns to maximize cycle energy production within operational constraints

    International Nuclear Information System (INIS)

    Hobson, G.H.; Turinsky, P.J.

    1986-01-01

    Computational capability has been developed to automatically determine the core loading pattern which minimizes fuel cycle costs for a pressurized water reactor. Equating fuel cycle cost minimization with core reactivity maximization, the objective is to determine the loading pattern which maximizes core reactivity at end-of-cycle while satisfying the power peaking constraint throughout the cycle and region average discharge burnup limit. The method utilizes a two-dimensional, coarse mesh, finite difference scheme to evaluate core reactivity and fluxes for an initial reference loading pattern as a function of cycle burnup. First order perturbation theory is applied to determine the effects of assembly shuffling on reactivity, power distribution, and end-of-cycle burnup

  16. Influence of sludge properties and hydraulic loading on the performance of secondary settling tanks--full-scale operational results.

    Science.gov (United States)

    Vestner, R J; Günthert, F Wolfgang

    2004-01-01

    Full-scale investigations at a WWTP with a two-stage secondary settling tank process revealed relationships between significant operating parameters and performance in terms of effluent suspended solids concentration. Besides common parameters (e.g. surface overflow rate and sludge volume loading rate) feed SS concentration and flocculation time must be considered. Concentration of the return activated sludge may help to estimate the performance of existing secondary settling tanks.

  17. Documentation of probabilistic fracture mechanics codes used for reactor pressure vessels subjected to pressurized thermal shock loading: Parts 1 and 2. Final report

    International Nuclear Information System (INIS)

    Balkey, K.; Witt, F.J.; Bishop, B.A.

    1995-06-01

    Significant attention has been focused on the issue of reactor vessel pressurized thermal shock (PTS) for many years. Pressurized thermal shock transient events are characterized by a rapid cooldown at potentially high pressure levels that could lead to a reactor vessel integrity concern for some pressurized water reactors. As a result of regulatory and industry efforts in the early 1980's, a probabilistic risk assessment methodology has been established to address this concern. Probabilistic fracture mechanics analyses are performed as part of this methodology to determine conditional probability of significant flaw extension for given pressurized thermal shock events. While recent industry efforts are underway to benchmark probabilistic fracture mechanics computer codes that are currently used by the nuclear industry, Part I of this report describes the comparison of two independent computer codes used at the time of the development of the original U.S. Nuclear Regulatory Commission (NRC) pressurized thermal shock rule. The work that was originally performed in 1982 and 1983 to compare the U.S. NRC - VISA and Westinghouse (W) - PFM computer codes has been documented and is provided in Part I of this report. Part II of this report describes the results of more recent industry efforts to benchmark PFM computer codes used by the nuclear industry. This study was conducted as part of the USNRC-EPRI Coordinated Research Program for reviewing the technical basis for pressurized thermal shock (PTS) analyses of the reactor pressure vessel. The work focused on the probabilistic fracture mechanics (PFM) analysis codes and methods used to perform the PTS calculations. An in-depth review of the methodologies was performed to verify the accuracy and adequacy of the various different codes. The review was structured around a series of benchmark sample problems to provide a specific context for discussion and examination of the fracture mechanics methodology

  18. Friction coefficient and limiter load test analysis by flexibility coefficient model of Hold-Down Spring of nuclear reactor vessel internals

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Linjun [Zhejiang Univ. of Technology, Hangzhou (China). College of Mechanical Engineering; Xue, Guohong; Zhang, Ming [Shanghai Nuclear Engineering Research and Design Institute, Shanghai (China)

    2017-11-15

    The friction force between the contact surfaces of a reactor internal hold-down spring (HDS) and core barrel flanges can directly influence the axial stiffness of an HDS. However, friction coefficient cannot be obtained through theoretical analysis. This study performs a mathematical deduction of the physical model of an HDS. Moreover, a mathematical model of axial load P, displacement δ, and flexibility coefficient is established, and a set of test apparatuses is designed to simulate the preloading process of the HDS. According to the experimental research and theoretical analysis, P-δ curves and the flexibility coefficient λ are obtained in the loading processes of the HDS. The friction coefficient f of the M1000 HDS is further calculated as 0.224. The displacement limit load value (4,638 kN) can be obtained through a displacement limit experiment. With the friction coefficient considered, the theoretical load is 4,271 kN, which is relatively close to the experimental result. Thus, the friction coefficient exerts an influence on the displacement limit load P. The friction coefficient should be considered in the design analysis for HDS.

  19. Friction coefficient and limiter load test analysis by flexibility coefficient model of Hold-Down Spring of nuclear reactor vessel internals

    International Nuclear Information System (INIS)

    Xie, Linjun

    2017-01-01

    The friction force between the contact surfaces of a reactor internal hold-down spring (HDS) and core barrel flanges can directly influence the axial stiffness of an HDS. However, friction coefficient cannot be obtained through theoretical analysis. This study performs a mathematical deduction of the physical model of an HDS. Moreover, a mathematical model of axial load P, displacement δ, and flexibility coefficient is established, and a set of test apparatuses is designed to simulate the preloading process of the HDS. According to the experimental research and theoretical analysis, P-δ curves and the flexibility coefficient λ are obtained in the loading processes of the HDS. The friction coefficient f of the M1000 HDS is further calculated as 0.224. The displacement limit load value (4,638 kN) can be obtained through a displacement limit experiment. With the friction coefficient considered, the theoretical load is 4,271 kN, which is relatively close to the experimental result. Thus, the friction coefficient exerts an influence on the displacement limit load P. The friction coefficient should be considered in the design analysis for HDS.

  20. Stress analysis on the valve of the rotating shield, coupled with fuel element loading-unloading machine in a PWR pressure vessel

    International Nuclear Information System (INIS)

    Albuquerque, L.B. de; Jesus Miranda, C.A. de.

    1992-01-01

    A finite element static analysis was performed with the valve of the Rotating Shield (RS) which is coupled with the Fuel. Element Loading-Unloading Machine under OBE earthquake. The applied leads were obtained from a previous seismic analysis with the response spectrum method of the MTC under OBE load. A 3-D model with shell elements was developed for the valve body and for a part of the RS. The ANSYS program, version 4.4 A, was used. The two main scopes of this work were to verify the valve stresses and the functionality of its moving parts during the earthquake. (author)

  1. 76 FR 13313 - Hazardous Materials: Cargo Tank Motor Vehicle Loading and Unloading Operations

    Science.gov (United States)

    2011-03-11

    ...-the-job complacency. As a result, PHMSA expects a reduction in the number of loading and unloading... monitoring of internal tank pressure and cargo temperature. C. CSB Accident Investigations CSB has... unloading practices is impractical. ATA states that, ``[i]t is critically important that PHMSA not choose a...

  2. Contribution of apparently non-operating loadings to the buckling of thin shells and plates

    International Nuclear Information System (INIS)

    Delaigue, Didier.

    1980-02-01

    This work includes four parts: in the first part, the Kirchhoff-Love theory of thin shells is described, a theory taken up and developed by Koiter and whose modelling seems to meet the problems of engineers. The second part deals with the buckling of a thin plate subjected to a load along a part of its edge, of which a part or all is seemingly inoperative. In the third part the study is extended to shells of any shape subjected to a conservative loading of the ''dead-loading'' type along part of their edges. On the basis of the results of the previous study, a study is then made on the taking into account of any load applied to the edge of a thin shell. In the fourth part the previous results are applied to the study of the buckling of a thin shell with a circular base subjected along a part of its edge to a normal prestress and to twisting moments linear density [fr

  3. Possible standards for relieving the load of operational thermal power plants to the minimum of the power system's electric loads

    Energy Technology Data Exchange (ETDEWEB)

    Gitman, M.I.; Smirnov, I.A.

    1988-03-01

    Describes how operational measures involving feeding the steam extraction load into existing off-peak hot-water boilers produce a reduction in electric power at night and on public holidays by an average of 35% without the need for reconstruction, special equipment or changing the heat circuit. This method enables coal-fired central heating systems to be relieved by 20-30% and gaz-mazout systems (the majority) by 50-70%. To compensate for the loss of manoeuverability in central heating units on holidays in the colder period of the year, it may be necessary to stop supplementary power units (KEhS units) several times a year. 5 refs.

  4. Elmo Bumpy Torus proof of principle, Phase II: Title 1 report. Volume II. Toroidal vessel

    International Nuclear Information System (INIS)

    1982-01-01

    The Toroidal Vessel provides the vacuum enclosure for containing the high temperature steady state plasma. In addition, the Toroidal Vessel must provide several viewing ports for plasma diagnostics, vacuum pumping ports for both high vacuum and roughing vacuum, feed-through ports for ECRH waveguides, limiter feed throughs for cooling and supporting the limiters, and ports for ion gages. The vessel must operate in an intense environment comprised of x-rays, microwaves, magnetic fields and plasma heat loads as well as the atmosphere pressure and gravity loads and the internal thermal stress loads due to heating and cooling of the torus. A key issue addressed was the choice of vacuum vessel seal and wall materials. In addition, during the course of the study, ORNL requested that horsecollar diagnostic ports be incorporated in the design. A comprehensive trade study was performed considering the vessel material issues in concert with the impact of the horsecollar port design. A change in baseline from an aluminum vessel with elastomer seals and circular diagnostic ports to austenitic stainless steel vessel with metal seals and horsecollar ports was agreed upon by both MDAC and ORNL towards the end of Title I

  5. LANL Robotic Vessel Scanning

    Energy Technology Data Exchange (ETDEWEB)

    Webber, Nels W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-25

    Los Alamos National Laboratory in J-1 DARHT Operations Group uses 6ft spherical vessels to contain hazardous materials produced in a hydrodynamic experiment. These contaminated vessels must be analyzed by means of a worker entering the vessel to locate, measure, and document every penetration mark on the vessel. If the worker can be replaced by a highly automated robotic system with a high precision scanner, it will eliminate the risks to the worker and provide management with an accurate 3D model of the vessel presenting the existing damage with the flexibility to manipulate the model for better and more in-depth assessment.The project was successful in meeting the primary goal of installing an automated system which scanned a 6ft vessel with an elapsed time of 45 minutes. This robotic system reduces the total time for the original scope of work by 75 minutes and results in excellent data accumulation and transmission to the 3D model imaging program.

  6. 19 CFR 4.97 - Salvage vessels.

    Science.gov (United States)

    2010-04-01

    ... United States and Great Britain ‘concerning reciprocal rights for United States and Canada in the... meaning of this statute. (e) A Mexican vessel may engage in a salvage operation on a Mexican vessel in any territorial waters of the United States in which Mexican vessels are permitted to conduct such operations by...

  7. Pressure vessels for reactors made from structural steel with limited tensile strength

    International Nuclear Information System (INIS)

    Machatti, H.

    1973-01-01

    The reactor pressure vessel is prestressed in several directions with prestressing elements fabricated of steel with a high yielding point. This design allows a substantial reduction of wall thickness or an increase of the inner diameter at equal wall thickness. The prestress of the prestressing elements is designed to achieve a maximum stress release of the vessel walls at normal operating conditions and to fully utilize the maximum load of the vessel walls. For safety reasons the cross section of the prestressing elements is constructed in a way that strain is always 20 % lower the yield point. (P.K.)

  8. Wind Energy Management System Integration Project Incorporating Wind Generation and Load Forecast Uncertainties into Power Grid Operations

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, Yuri V.; Huang, Zhenyu; Etingov, Pavel V.; Ma, Jian; Guttromson, Ross T.; Subbarao, Krishnappa; Chakrabarti, Bhujanga B.

    2010-09-01

    features make this work a significant step forward toward the objective of incorporating of wind, solar, load, and other uncertainties into power system operations. In this report, a new methodology to predict the uncertainty ranges for the required balancing capacity, ramping capability and ramp duration is presented. Uncertainties created by system load forecast errors, wind and solar forecast errors, generation forced outages are taken into account. The uncertainty ranges are evaluated for different confidence levels of having the actual generation requirements within the corresponding limits. The methodology helps to identify system balancing reserve requirement based on a desired system performance levels, identify system “breaking points”, where the generation system becomes unable to follow the generation requirement curve with the user-specified probability level, and determine the time remaining to these potential events. The approach includes three stages: statistical and actual data acquisition, statistical analysis of retrospective information, and prediction of future grid balancing requirements for specified time horizons and confidence intervals. Assessment of the capacity and ramping requirements is performed using a specially developed probabilistic algorithm based on a histogram analysis incorporating all sources of uncertainty and parameters of a continuous (wind forecast and load forecast errors) and discrete (forced generator outages and failures to start up) nature. Preliminary simulations using California Independent System Operator (California ISO) real life data have shown the effectiveness of the proposed approach. A tool developed based on the new methodology described in this report will be integrated with the California ISO systems. Contractual work is currently in place to integrate the tool with the AREVA EMS system.

  9. Selenium concentrations and loads from coal mining operations in the Elk River Watershed, Southeastern BC : 2004-2009

    International Nuclear Information System (INIS)

    Paine, M.; Orr, P.; Franklin, W.; Fraser, C.

    2010-01-01

    This presentation reported on a study in which selenium concentrations were measured at 27 receiving and 40 discharge water stations in British Columbia's Elk River watershed, where Teck Coal Ltd. operates 5 coal mines. Monthly measurements were taken in the Elk River and its major tributaries from 2004 to 2009 to evaluate trends for selenium concentrations in receiving waters, and for concentrations and loads at selected discharges. Selenium concentrations were found to be much higher than background levels of 1 g/L in areas downstream of mine discharges in the Fording River, Line Creek, Michel Creek and in the lower Elk River below its confluence with the Fording River. Concentrations increased considerably over time in the Fording and lower Elk Rivers, and in Line Creek. Most of the selenium loads discharged to the Elk River and its tributaries were found to originate from less than 10 major sources. Concentrations increased with time at most major sources. At some sources, selenium loads increased with time, but decreased at others. The increase in concentrations in the lower Elk River and at several major sources from 2007 to 2009 may be attributed in part to a decrease in flow. Options for reducing selenium loads discharged to downstream receiving waters are being investigated by the mines.

  10. Fission gas release behavior of MOX fuels under simulated daily-load-follow operation condition. IFA-554/555 test evaluation with FASTGRASS code

    International Nuclear Information System (INIS)

    Ikusawa, Yoshihisa; Ozawa, Takayuki

    2008-03-01

    IFA-554/555 load-follow tests were performed in HALDEN reactor (HBWR) to study the MOX fuel behavior under the daily-load-follow operation condition in the framework of ATR-MOX fuel development in JAEA. IFA-554/555 rig had the instruments of rod inner pressure, fuel center temperature, fuel stack elongation, and cladding elongation. Although the daily-load-follow operation in nuclear power plant is one of the available options for economical improvement, the power change in a short period in this operation causes the change of thermal and mechanical irradiation conditions. In this report, FP gas release behavior of MOX fuel rod was evaluated under the daily-load-follow operation condition with the examination data from IFA-554/555 by using the computation code 'FASTGRASS'. From the computation results of FASTGRASS code which could compute the FP gas release behavior under the transient condition, it could be concluded that FP gas was released due to the relaxation of fuel pellet inner stress and pellet temperature increase, which were caused by the cyclic power change during the daily-load-follow operation. In addition, since the amount of released FP gas decreased during the steady operation after the daily-load-follow, it could be mentioned that the total of FP gas release at the end of life with the daily-load-follow is not so much different from that without the daily-load-follow. (author)

  11. Bifurcation Analysis of a DC-DC Bidirectional Power Converter Operating with Constant Power Loads

    Science.gov (United States)

    Cristiano, Rony; Pagano, Daniel J.; Benadero, Luis; Ponce, Enrique

    Direct current (DC) microgrids (MGs) are an emergent option to satisfy new demands for power quality and integration of renewable resources in electrical distribution systems. This work addresses the large-signal stability analysis of a DC-DC bidirectional converter (DBC) connected to a storage device in an islanding MG. This converter is responsible for controlling the balance of power (load demand and generation) under constant power loads (CPLs). In order to control the DC bus voltage through a DBC, we propose a robust sliding mode control (SMC) based on a washout filter. Dynamical systems techniques are exploited to assess the quality of this switching control strategy. In this sense, a bifurcation analysis is performed to study the nonlinear stability of a reduced model of this system. The appearance of different bifurcations when load parameters and control gains are changed is studied in detail. In the specific case of Teixeira Singularity (TS) bifurcation, some experimental results are provided, confirming the mathematical predictions. Both a deeper insight in the dynamic behavior of the controlled system and valuable design criteria are obtained.

  12. Get In and Get Out: Assessing Stream Sediment Loading from Short Duration Forest Harvest Operations and Rapid Haul Road Decommissioning.

    Science.gov (United States)

    Corrigan, A.; Silins, U.; Stone, M.

    2016-12-01

    Best management practices (BMPs) and associated erosion control measures for mitigating sediment impacts from forestry roads and road-stream crossings are well documented. While rapid road decommissioning after forestry operations may serve to limit broader impacts on sediment production in high value headwater streams, few studies have evaluated the combined effects of accelerated harvest operations and rapid retirement of logging roads and road-stream crossings on stream sediment. The objectives of this study were to evaluate the initial impacts of these strategies on fine sediment loading and fate during a short duration harvesting operation in 3 headwater sub-catchments in the southwestern Rocky Mountains of Alberta, Canada. A multi-pronged sampling approach (ISCOs, event focused grab sampling, continuous wash load sampling, and stream bed sediment intrusion measurements) was used to measure sediment loading and deposition in streambeds upstream and downstream of road-stream bridge crossings during harvest operations (2015) and after road and bridge crossing retirement (2016). Sediment production from forestry roads was generally much lower than has been reported from other studies in similar settings. Average total suspended solids (TSS) downstream of the bridge crossings were actually lower (-3.28 g/L; -0.704 g/L) than upstream of two bridge crossings while in-stream sediment sources contributed to elevated sediment downstream of a third road-stream crossing. Minimal in stream sediment impacts from forest harvest and road-stream crossings was likely a reflection of combined factors including a) employment of erosion control BMPs to roads and bridge crossings, b) rapid decommissioning of roads and crossings to limit exposure of linear land disturbance features, and c) drier El Niño climatic conditions during the study.

  13. Structural analysis of the JT-60SA cryostat vessel body

    Energy Technology Data Exchange (ETDEWEB)

    Botija, José, E-mail: jose.botija@ciemat.es [Association EURATOM – CIEMAT, Avda. Complutense 40, 28040 Madrid (Spain); Alonso, Javier; Fernández, Pilar; Medrano, Mercedes; Ramos, Francisco; Rincon, Esther; Soleto, Alfonso [Association EURATOM – CIEMAT, Avda. Complutense 40, 28040 Madrid (Spain); Davis, Sam; Di Pietro, Enrico; Tomarchio, Valerio [Fusion for Energy, JT-60SA European Home Team, 85748 Garching bei Munchen (Germany); Masaki, Kei; Sakasai, Akira; Shibama, Yusuke [JAEA – Japan Atomic Energy Agency, Naka Fusion Institute, Ibaraki 311-0193 (Japan)

    2013-10-15

    Highlights: ► Structural analysis to validate the JT-60SA cryostat vessel body design. ► Design code ASME 2007 “Boiler and Pressure Vessel Code. Section VIII”. ► First buckling mode: load multiplier of 10.644, higher than the minimum factor 4.7. ► Elastic and elastic–plastic stress analysis meets ASME against plastic collapse. ► Bolted fasteners have been analyzed showing small gaps closed by strong welding. -- Abstract: The JT-60SA cryostat is a stainless steel vacuum vessel (14 m diameter, 16 m height) which encloses the Tokamak providing the vacuum environment (10{sup −3} Pa) necessary to limit the transmission of thermal loads to the components at cryogenic temperature. It must withstand both external atmospheric pressure during normal operation and internal overpressure in case of an accident. The paper summarizes the structural analyses performed in order to validate the JT-60SA cryostat vessel body design. It comprises several analyses: a buckling analysis to demonstrate stability under the external pressure; an elastic and an elastic–plastic stress analysis according to ASME VIII rules, to evaluate resistance to plastic collapse including localized stress concentrations; and, finally, a detailed analysis with bolted fasteners in order to evaluate the behavior of the flanges, assuring the integrity of the vacuum sealing welds of the cryostat vessel body.

  14. Stochastic Modeling of Unloading and Loading Operations at a Container Terminal using Automated Lifting Vehicles

    NARCIS (Netherlands)

    D. Roy (Debjit); M.B.M. de Koster (René)

    2015-01-01

    textabstractWith growing worldwide trade, container terminals have grown in number and size. Many new terminals are now automated to increase operational efficiency. The key focus is on improving seaside processes, where a distinction can be made between single quay crane operations (all quay

  15. Hierarchical Load Tracking Control of a Grid-connected Solid Oxide Fuel Cell for Maximum Electrical Efficiency Operation

    DEFF Research Database (Denmark)

    Li, Yonghui; Wu, Qiuwei; Zhu, Haiyu

    2015-01-01

    efficiency operation obtained at different active power output levels, a hierarchical load tracking control scheme for the grid-connected SOFC was proposed to realize the maximum electrical efficiency operation with the stack temperature bounded. The hierarchical control scheme consists of a fast active...... power control and a slower stack temperature control. The active power control was developed by using a decentralized control method. The efficiency of the proposed hierarchical control scheme was demonstrated by case studies using the benchmark SOFC dynamic model......Based on the benchmark solid oxide fuel cell (SOFC) dynamic model for power system studies and the analysis of the SOFC operating conditions, the nonlinear programming (NLP) optimization method was used to determine the maximum electrical efficiency of the grid-connected SOFC subject...

  16. 46 CFR 170.095 - Data submittal for a vessel equipped to lift.

    Science.gov (United States)

    2010-10-01

    ... vessel is engaged in lifting and is required to comply with subpart B of part 173 of this chapter: (a) A graph of maximum hook load versus maximum crane radius. (b) A table of crane radius versus the maximum... transverse moments at which the crane is to operate. ...

  17. Coordinated control of smart microgrid during and after islanding operation to prevent under frequency load shedding using energy storage system

    International Nuclear Information System (INIS)

    Koohi-Kamali, Sam; Rahim, Nasrudin Abd

    2016-01-01

    Highlights: • A new power management system is proposed. • The novel idea of using energy storage systems to prevent under frequency load shedding is presented. • A method to estimate rate of change of frequency in islanding mode and to dispatch battery plant is introduced. • Two effective outer control loops are proposed for governor to synchronize the microgrid with main grid. • Solar photovoltaic and battery plants bring the voltage regulation ancillary service for microgrid. - Abstract: This work presents a smart microgrid consisting of diesel, photovoltaic (PV), and battery storage plants. One of the key features of smart grid is to provide a redundant high quality power for the consumers. In islanded microgrid, the under frequency and/or voltage collapse, caused by power deficiency, can lead to power outage. The current practice is to shed the load demand until the frequency and voltage are restored. However, the redundancy in supplying power has no meaning as long as the loads are shed. The main objective of this paper is to propose a power management system (PMS) that protects the microgrid against the load shedding. PMS is able to control the microgrid in both centralized and decentralized fashions. To prevent under frequency load shedding (UFLS), this work proposes using battery energy storage system (BESS) to compensate for the power mismatch in the islanded microgrid. A method is presented to estimate the rate of change of frequency and to calculate the power deficiency. The approximated value is exploited as the set-point to dispatch BESS. PV and battery plants are supposed to share the reactive power demand proportionally and thus regulate the voltage at the load bus. This work also suggests two outer control loops, namely, frequency restoration loop (FRL) and difference angle compensator (DAC). These loops ensure microgrid smooth transition from islanded mode to grid-connected mode. The microgrid is configured to investigate the effective

  18. Safeguarding subcriticality during loading and shuffling operations in the higher density of the RSG-GAS's silicide core

    International Nuclear Information System (INIS)

    Sembiring, T.M.; Kuntoro, I.

    2003-01-01

    The core conversion program of the RSG-GAS reactor is to convert the all-oxide to all-silicide core. The silicide equilibrium core with fuel meat density of 3.55 gU cm -3 is an optimal core for RSG-GAS reactor and it can significantly increase the operation cycle length from 25 to 32 full power days. Nevertheless, the subcriticality of the shutdown core and the shutdown margin are lower than of the oxide core. Therefore, the deviation of subcriticality condition in the higher silicide core caused by the fuel loading and shuffling error should be reanalysed. The objective of this work is to analyse the sufficiency of the subcriticality condition of the shutdown core to face the worst condition caused by an error during loading and shuffling operations. The calculations were carried out using the 2-dimensional multigroup neutron diffusion code of Batan-FUEL. In the fuel handling error, the calculated results showed that the subcriticality condition of the shutdown higher density silicide equilibrium core of RSG-GAS can be maintained. Therefore, all fuel management steps are fixed in the present reactor operation manual can be applied in the higher silicide equilibrium core of RSG-GAS reactor. (author)

  19. Prestressed reactor vessel for nuclear power plants

    International Nuclear Information System (INIS)

    Schoening, J.; Schwiers, H.G.

    1982-01-01

    With usual pressure vessels for nuclear reactor plants, especially for gas-cooled nuclear reactors, the load occurring due to the inner overpressure, especially the tensile load affecting the vessel top and/or bottom, their axis of inertia being horizontal, shall be compensated without a supplementary modification in design of the top and/or the bottom. This is attained by choosing an appropriate prestressing system of the vessel wall in the field the top and/or the bottom, so that the top and/or the bottom form a tension vault directed towards the interior of the vessel. (orig.) [de

  20. Containment vessel design and practice

    International Nuclear Information System (INIS)

    Bangash, Y.

    1983-01-01

    The state of the art of analysis and design of the concrete containment vessels required for BWR and PWR is reviewed. A step-by-step critical appraisal of the existing work is given. Elastic, inelastic and cracking conditions under extreme loads are fully discussed. Problems associated with these structures are highlighted. A three-dimensional finite element analysis is included to cater for service, overload and dynamic cracking of such structures. Missile impact and seismic effects are included in this work. The second analysis is known as the limit state analysis, which is given to design such vessels for any kind of load. (U.K.)

  1. Atucha II NPP (nuclear power plant). Analysis of the stress generated by special loads in the upper lateral support of the reactor pressure vessel

    International Nuclear Information System (INIS)

    Mancini, G.R.; Jaichenco, M.; Alvarez, L.M.

    1988-01-01

    This report is aimed at introducing the results of a study performed for assessing the mechanical behavior occurred after the introduction of the tangential component of stresses generated by accident-related loads in the RPV's support shield. Significant modifications have been made to the original structural design of the support on the basis of the results from such study, while taking into account the confinement effects produced by the joint action of an adequate steel reinforcing arrangement and of an external armoring plate. (Author) [es

  2. Nefopam hydrochloride loaded microspheres for post-operative pain management: synthesis, physicochemical characterization and in-vivo evaluation.

    Science.gov (United States)

    Sharma, Neelam; Arora, Sandeep; Madan, Jitender

    2018-02-01

    Once-daily oral dosage of nefopam hydrochloride loaded sustained release microspheres (NPH-MS) was investigated as novel therapeutic strategy for post-operative pain management. Microspheres were synthesized using poly-3-hydroxybutyrate and poly-(ɛ-caprolactone) by double emulsion solvent evaporation technique. NPH-MS were characterized through FTIR, PXRD and SEM. In-vitro drug release study revealed sustained behavior till 24 h. Haemolysis was pain model, reversal of mechanical allodynia and thermal hyperalgesia by NPH-MS was statistically significant (p < .001) as compared with NPH till 24 h post-dose.

  3. Sealing analysis for nuclear vessels of PWR

    International Nuclear Information System (INIS)

    Qu Jiadi; Dou Yikang

    1988-01-01

    The fundamental equations of sealing analysis for vessels are given and a computer program named SMEC, which considers the change of stud loading, the elastic contact between flange mating surfaces and the transient thermal effects, is developed accordingly. The SMEC is verified by several test. On the basis of analysis, a new concept of classifying vessels into three types according to increasing or decreasing of bolt loading with increasing pressure is suggested. Type-A vessel is that in which the bolt loading increases monotonically with increasing pressure, while in type-B, the bolt loading decreases monotonically, and in type-C, the bolt loading changes nonmonotonically. It is important for vessel design to distinguish the types through analysis. The sealing mechanism is also discussed

  4. Analytical and experimental justification of safe operation of fuel loads of VVER reactors at Rovno NPP

    International Nuclear Information System (INIS)

    Andrianov, A.; Zagrebelny, L.

    2011-01-01

    The main task during the nuclear fuel operation us ensuring of the larger fuel burnup and as a result - reduction of the fuel constituent in the electricity production cost. The neutron-physic calculations are performed using the qualified codes BIPR-7A and PERMAK developed by Kurchatov Institute. The limits for calculated parameters are set by the Ukrainian regulations. Calculation results are documented in reports subject for independent expert review requested by the regulatory authority. In this report the following item have presented: 1) metrological check and calibration of measuring channels; 2) fuel cycles at Rivne NPP; 3) determination of experimental values of thermal-physic and neutron-physic parameters; 4) ICIS equipment check, execution of the program confirming correct connection of the temperature and neutron flux monitoring sensors; 5) monitoring of the core TPh and NPh parameters in all operating modes; 6) monitoring of the fuel condition in the core and 7) FE leak tightness monitoring at the operating reactor

  5. The effect of joystick handle size and gain at two levels of required precision on performance and physical load on crane operators

    NARCIS (Netherlands)

    Huysmans, M.A.; Looze, M.P. de; Hoozemans, M.J.M.; Beek, A.J. van der; Dieën, J.H. van

    2006-01-01

    The study was designed to determine the effect of joystick handle size and (display-control) gain at two levels of required task precision on performance and physical load on crane operators. Eight experienced crane operators performed a simulated crane operation task on a computer by use of a

  6. ITER cryostat main chamber and vacuum vessel pressure suppression system design

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Akira; Nakahira, Masataka; Takahashi, Hiroyuki; Tada, Eisuke [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakashima, Yoshitane; Ueno, Osamu

    1999-03-01

    Design of Cryostat Main Chamber and Vacuum Vessel Pressure Suppression System (VVPS) of International Thermonuclear Experimental Reactor (ITER) has been conducted. The cryostat is a cylindrical vessel that includes in-vessel component such as vacuum vessel, superconducting toroidal coils and poloidal coils. This cryostat provides the adiabatic vacuum about 10{sup -4} Pa for the superconducting coils operating at 4 K and forms the second confinement barrier to tritium. The adiabatic vacuum is to reduce thermal loads applied to the superconducting coils and their supports so as to keep their temperature 4 K. The VVPS consists of a suppression tank located under the lower bio-shield and 4 relief pipes to connect the vacuum vessel and the suppression tank. The VVPS is to keep the maximum pressure rise of the vacuum vessel below the design value of 0.5 MPa in case of the in-vessel LOCA (water spillage from in-vessel component). The spilled water and steam are lead to the suppression tank through the relief pipes when the internal pressure of vacuum vessel is over 0.2 MPa, and then the internal pressure is kept below 0.5 MPa. This report summarizes the structural design of the cryostat main chamber and pressure suppression system, together with their fabrication and installation. (author)

  7. ITER cryostat main chamber and vacuum vessel pressure suppression system design

    International Nuclear Information System (INIS)

    Ito, Akira; Nakahira, Masataka; Takahashi, Hiroyuki; Tada, Eisuke; Nakashima, Yoshitane; Ueno, Osamu

    1999-03-01

    Design of Cryostat Main Chamber and Vacuum Vessel Pressure Suppression System (VVPS) of International Thermonuclear Experimental Reactor (ITER) has been conducted. The cryostat is a cylindrical vessel that includes in-vessel component such as vacuum vessel, superconducting toroidal coils and poloidal coils. This cryostat provides the adiabatic vacuum about 10 -4 Pa for the superconducting coils operating at 4 K and forms the second confinement barrier to tritium. The adiabatic vacuum is to reduce thermal loads applied to the superconducting coils and their supports so as to keep their temperature 4 K. The VVPS consists of a suppression tank located under the lower bio-shield and 4 relief pipes to connect the vacuum vessel and the suppression tank. The VVPS is to keep the maximum pressure rise of the vacuum vessel below the design value of 0.5 MPa in case of the in-vessel LOCA (water spillage from in-vessel component). The spilled water and steam are lead to the suppression tank through the relief pipes when the internal pressure of vacuum vessel is over 0.2 MPa, and then the internal pressure is kept below 0.5 MPa. This report summarizes the structural design of the cryostat main chamber and pressure suppression system, together with their fabrication and installation. (author)

  8. Hierarchical Load Tracking Control of a Grid-Connected Solid Oxide Fuel Cell for Maximum Electrical Efficiency Operation

    Directory of Open Access Journals (Sweden)

    Yonghui Li

    2015-03-01

    Full Text Available Based on the benchmark solid oxide fuel cell (SOFC dynamic model for power system studies and the analysis of the SOFC operating conditions, the nonlinear programming (NLP optimization method was used to determine the maximum electrical efficiency of the grid-connected SOFC subject to the constraints of fuel utilization factor, stack temperature and output active power. The optimal operating conditions of the grid-connected SOFC were obtained by solving the NLP problem considering the power consumed by the air compressor. With the optimal operating conditions of the SOFC for the maximum efficiency operation obtained at different active power output levels, a hierarchical load tracking control scheme for the grid-connected SOFC was proposed to realize the maximum electrical efficiency operation with the stack temperature bounded. The hierarchical control scheme consists of a fast active power control and a slower stack temperature control. The active power control was developed by using a decentralized control method. The efficiency of the proposed hierarchical control scheme was demonstrated by case studies using the benchmark SOFC dynamic model.

  9. Containment vessel

    International Nuclear Information System (INIS)

    Zbirohowski-Koscia, K.F.; Roberts, A.C.

    1980-01-01

    A concrete containment vessel for nuclear reactors is disclosed that is spherical and that has prestressing tendons disposed in first, second and third sets, the tendons of each set being all substantially concentric and centred around a respective one of the three orthogonal axes of the sphere; the tendons of the first set being anchored at each end at a first anchor rib running around a circumference of the vessel, the tendons of the second set being anchored at each end at a second anchor rib running around a circumference of the sphere and disposed at 90 0 to the first rib, and the tendons of the third set being anchored some to the first rib and the remainder to the second rib. (author)

  10. Integrating UF6 Cylinder RF Tracking With Continuous Load Cell Monitoring for Verifying Declared UF6 Feed and Withdrawal Operations Verifying Declared UF6 Feed and Withdrawal Operations

    International Nuclear Information System (INIS)

    Krichinsky, Alan M.; Miller, Paul; Pickett, Chris A.; Richardson, Dave; Rowe, Nathan C.; Whitaker, J. Michael; Younkin, James R.

    2009-01-01

    Oak Ridge National Laboratory is demonstrating the integration of UF6 cylinder tracking, using RF technology, with continuous load cell monitoring (CLCM) at mock UF6 feed and withdrawal (F and W) stations. CLCM and cylinder tracking are two of several continuous-monitoring technologies that show promise in providing integrated safeguards of F and W operations at enrichment plants. Integrating different monitoring technologies allows advanced, automated event processing to screen innocuous events thereby minimizing false alerts to independent inspectors. Traditionally, international inspectors rely on batch verification of material inputs and outputs derived from operator declarations and periodic on-site inspections at uranium enrichment plants or other nuclear processing facilities. Continuously monitoring F and W activities between inspections while providing filtered alerts of significant operational events will substantially increase the amount of valuable information available to inspectors thereby promising to enhance the effectiveness of safeguards and to improve efficiency in conducting on-site inspections especially at large plants for ensuring that all operations are declared.

  11. Stress state of thin – walled member of the structure with operation damages under nonuniform loading

    Directory of Open Access Journals (Sweden)

    В.В. Астанін

    2004-01-01

    Full Text Available  The publication is dedicated to determining of stress state in particular the stress concentration factors for thin – walled members of the structures subject to nonuniform tension. A structure member has obtained the operation damage generation by corrosion and other causes.

  12. Numerical modelling of electromagnetic loads on fusion device structures

    International Nuclear Information System (INIS)

    Bettini, Paolo; Palumbo, Maurizio Furno; Specogna, Ruben

    2014-01-01

    In magnetic confinement fusion devices, during abnormal operations (disruptions) the plasma begins to move rapidly towards the vessel wall in a vertical displacement event (VDE), producing plasma current asymmetries, vessel eddy currents and open field line halo currents, each of which can exert potentially damaging forces upon the vessel and in-vessel components. This paper presents a methodology to estimate electromagnetic loads, on three-dimensional conductive structures surrounding the plasma, which arise from the interaction of halo-currents associated to VDEs with a magnetic field of the order of some Tesla needed for plasma confinement. Lorentz forces, calculated by complementary formulations, are used as constraining loads in a linear static structural analysis carried out on a detailed model of the mechanical structures of a representative machine

  13. Numerical modelling of electromagnetic loads on fusion device structures

    Science.gov (United States)

    Bettini, Paolo; Furno Palumbo, Maurizio; Specogna, Ruben

    2014-03-01

    In magnetic confinement fusion devices, during abnormal operations (disruptions) the plasma begins to move rapidly towards the vessel wall in a vertical displacement event (VDE), producing plasma current asymmetries, vessel eddy currents and open field line halo currents, each of which can exert potentially damaging forces upon the vessel and in-vessel components. This paper presents a methodology to estimate electromagnetic loads, on three-dimensional conductive structures surrounding the plasma, which arise from the interaction of halo-currents associated to VDEs with a magnetic field of the order of some Tesla needed for plasma confinement. Lorentz forces, calculated by complementary formulations, are used as constraining loads in a linear static structural analysis carried out on a detailed model of the mechanical structures of a representative machine.

  14. Evaluation of occupational physical load during 6-month international crisis management operation.

    Science.gov (United States)

    Pihlainen, Kai; Santtila, Matti; Vasankari, Tommi; Häkkinen, Keijo; Kyröläinen, Heikki

    2018-01-07

    Generally, operational military duties are associated with a variety of stressors, such as prolonged physical activity (PA). However, limited information is available on the occupational workload or changes in PA during international military operations. Thus, the aim of the study was to investigate the changes in body composition, stress biomarkers, PA, and heart rate (HR) responses of 79 male soldiers during a 6-month international crisis management operation. Measurements were conducted 3 times in South-Lebanon during the operation. Body composition was assessed by the bioelectrical impedance method. Blood samples were analyzed for serum testosterone, sex-hormone binding globulin (SHBG), cortisol and insulin-like growth factor. Saliva sampling was used for analyzing stress biomarkers, cortisol and α-amylase. Heart rate and physical activity were monitored by a recordable belt and tri-axial accelerometer, respectively. Increases in muscle mass (39.2±4.1 vs. 39.5±4.2 kg, p PRE-MID) of the study. The increase in muscle mass remained significant during the latter half (PRE-POST, 39.2±4.1 vs. 39.6±4.4 kg, p PRE-POST, 36.5±33.7 vs. 55.1±39.7 U/ml), the acute stress biomarkers and HR responses remained unchanged. Furthermore, the low quantity of PA, low HR values and subjective ratings of exertion refer to rather light physical workload. Due to the operatively calm nature of the working environment, the present soldiers did not express any significant signs of physical overload during the study period. Int J Occup Med Environ Health 2018;31(2):185-197. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  15. Full vessel CFD analysis on thermal-hydraulic characteristics of CPR1000 PWR

    International Nuclear Information System (INIS)

    Chao Yanmeng; Yang Lixin; Zhang Mingqian

    2014-01-01

    To obtain flow distributions and thermal-hydraulic properties in a full vessel PWR under limited computation ability and time, a full vessel simulation model of CPR1000 was built based on two simplification methods. One simplified the inner geometry of the control rod guide tubes using equivalent flow area. Another substituted the core by a porous domain to maintain the pressure drop and temperature rise. After the computation, global and localized flow distributions, hydraulic loads of some main assemblies were obtained, as well as other thermal-hydraulic properties. The results indicate the flow distribution in the full vessel is asymmetrical. Therefore it is essential to use the full vessel model to simulate. The calculated thermal-hydraulic characteristics agree well with the operation statistics, providing the reference data for the reactor safety operation. (authors)

  16. An intelligent nuclear reactor core controller for load following operations, using recurrent neural networks and fuzzy systems

    International Nuclear Information System (INIS)

    Boroushaki, M.; Ghofrani, M.B.; Lucas, C.; Yazdanpanah, M.J.

    2003-01-01

    In the last decade, the intelligent control community has paid great attention to the topic of intelligent control systems for nuclear plants (core, steam generator...). Papers mostly used approximate and simple mathematical SISO (single-input-single-output) model of nuclear plants for testing and/or tuning of the control systems. They also tried to generalize theses models to a real MIMO (multi-input-multi-output) plant, while nuclear plants are typically of complex nonlinear and multivariable nature with high interactions between their state variables and therefore, many of these proposed intelligent control systems are not appropriate for real cases. In this paper, we designed an on-line intelligent core controller for load following operations, based on a heuristic control algorithm, using a valid and updatable recurrent neural network (RNN). We have used an accurate 3-dimensional core calculation code to represent the real plant and to train the RNN. The results of simulation show that this intelligent controller can control the reactor core during load following operations, using optimum control rod groups manoeuvre and variable overlapping strategy. This methodology represents a simple and reliable procedure for controlling other complex nonlinear MIMO plants, and may improve the responses, comparing to other control systems

  17. Determination of residual load-bearing capacity of concrete beams at the operation stage by the strength reinforcement and concrete criterion

    OpenAIRE

    V.S. Utkin

    2015-01-01

    An experimental theoretical method was considered for estimating the residual load-bearing capacity of an individual reinforced concrete beam at the operational stage according to the criteria of the working strength and durability of concrete reinforcement compressed zone of the beam. Integrated methods of beam testing and probabilistic methods of random variables definition were used. Ultimate load in the form of interval during the operational phase was accepted as the measure of carr...

  18. Disruptions, loads, and dynamic response of ITER

    International Nuclear Information System (INIS)

    Nelson, B.; Riemer, B.; Sayer, R.; Strickler, D.; Barabaschi, P.; Ioki, K.; Johnson, G.; Shimizu, K.; Williamson, D.

    1995-01-01

    Plasma disruptions and the resulting electromagnetic loads are critical to the design of the vacuum vessel and in-vessel components of the International Thermonuclear Experimental Reactor (ITER). This paper describes the status of plasma disruption simulations and related analysis, including the dynamic response of the vacuum vessel and in-vessel components, stresses and deflections in the vacuum vessel, and reaction loads in the support structures

  19. PWR vessel flaw distribution development

    International Nuclear Information System (INIS)

    Rosinski, S.T.; Kennedy, E.L.; Foulds, J.R.; Kinsman, K.M.

    1990-01-01

    This paper reports on PWR pressure vessels which operate under NRC rules and regulatory guides intended to prevent failure of the vessels. Plants failing to meet the operating criteria specified under these rules and regulations are required to analytically demonstrate fitness for service in order to continue operation. The initial flaw size or distribution of initial vessel flaws is a key input to the required vessel integrity analyses. However, the flaw distribution assumed in the development of the NRC Regulations and recommended for the plant specific analyses is potentially over-conservative. This is because the distribution is based on the limited amount of vessel inspection data available at the time the criteria were being developed and does not take full advantage of the more recent and reliable domestic vessel inspection results. The U.S. Department of Energy is funding an effort through Sandia National Laboratories to investigate the possibility of developing a new flaw distribution based on the increased amount and improved reliability of domestic vessel inspection data. Results of Phase I of the program indicate that state-of-the-art NDE systems' capabilities are sufficient for development of a new flaw distribution that could ultimately provide life extension benefits over the presently required operating practice

  20. Quantitative assessment of information load on control room operator in emergency situations

    International Nuclear Information System (INIS)

    Filshtein, E.L.

    1986-01-01

    The information processing by the operator in reading-from-display mode is addressed with the following conclusions: 1) The information measure which is needed should be translatable into the time requirements and as such, should reflect the peculiarities associated with mental information processing abilities. 2) The Information Processing Unit (IPU) is introduced as a measure that reflects the peculiarities and, therefore, is better than the Information Entropy unit (H) for the problem under consideration. 3) All the messages that the operator might encounter are classified as belonging to one of three types, and the amount of processing information is quantified in the Information Processing Units (IPU). 4) A pilot study has been conducted to verify underlined assumptions and to evaluate the rate of information processing in reading-from-display mode

  1. Emotional learning based intelligent controller for a PWR nuclear reactor core during load following operation

    International Nuclear Information System (INIS)

    Khorramabadi, Sima Seidi; Boroushaki, Mehrdad; Lucas, Caro

    2008-01-01

    The design and evaluation of a novel approach to reactor core power control based on emotional learning is described. The controller includes a neuro-fuzzy system with power error and its derivative as inputs. A fuzzy critic evaluates the present situation, and provides the emotional signal (stress). The controller modifies its characteristics so that the critic's stress is reduced. Simulation results show that the controller has good convergence and performance robustness characteristics over a wide range of operational parameters

  2. Effect of unbalanced voltage on windings temperature, operational life and load carrying capacity of induction machine

    Energy Technology Data Exchange (ETDEWEB)

    Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska Street 83, 81-225 Gdynia (Poland)

    2008-04-15

    This paper investigates the influence of the CVUF angle on the windings temperature rise and the derating factor of an induction machine supplied with unbalanced voltage. The effect of simultaneous voltage unbalance and harmonics on its operational life is analyzed as well. The results of calculations and experimental investigations are presented for two induction cage machines of rated power 3 and 5.5 kW. (author)

  3. Engineering analysis of ITER In-Vessel Viewing System guide tube

    Energy Technology Data Exchange (ETDEWEB)

    Casal, Natalia, E-mail: natalia.casal@iter.org [ITER Organization, Route de Vinon sur Verdon, St Paul-lez-Durance (France); Bates, Philip [Fusion for Energy, Barcelona (Spain); Bede, Ottó [Oxford Technologies Ltd., Abingdon (United Kingdom); Damiani, Carlo; Dubus, Gregory [Fusion for Energy, Barcelona (Spain); Omran, Hassan [Oxford Technologies Ltd., Abingdon (United Kingdom); Palmer, Jim [ITER Organization, Route de Vinon sur Verdon, St Paul-lez-Durance (France); Puiu, Adrian [Fusion for Energy, Barcelona (Spain); Reichle, Roger; Suárez, Alejandro; Walker, Christopher; Walsh, Michael [ITER Organization, Route de Vinon sur Verdon, St Paul-lez-Durance (France)

    2015-10-15

    Highlights: • Conceptual design of IVVS Loads action on IVVS Dominant loads. • Seismic and baking conditions. • No active cooling needed for IVVS. • IVVS requires additional support points to avoid excessive deformation. - Abstract: The In Vessel Viewing System (IVVS) will be one of the essential machine diagnostic systems at ITER to provide information about the status of in-vessel and plasma facing components and to evaluate the dust inside the Vacuum Vessel. The current design consists of six scanning probes and their deployment systems, which are placed in dedicated ports at the divertor level. These units are located in resident guiding tubes 10 m long, which allow the IVVS probes to go from their storage location to the scanning position by means of a simple straight translation. Moreover, each resident tube is supported inside the corresponding Vacuum Vessel and Cryostat port extensions, which are part of the primary confinement barrier. As the Vacuum Vessel and the Cryostat will move with respect to each other during operation (especially during baking) and during incidents and accidents (disruptions, vertical displacement events, seismic events), the structural integrity of the resident tube and the surrounding vacuum boundaries would be compromised if the required flexibility and supports are not appropriately assured. This paper focuses on the integration of the present design of the IVVS into the Vacuum Vessel and Cryostat environment. It presents the adopted strategy to withstand all the main interfacing loads without damaging the confinement barriers and the corresponding analysis supporting it.

  4. Amplitude-to-code converter for photomultipliers operating at high loadings

    International Nuclear Information System (INIS)

    Arkhangel'skij, B.V.; Evgrafov, G.N.; Pishchal'nikov, Yu.M.; Shuvalov, R.S.

    1982-01-01

    An 11-bit amplitude-to-code converter intended for the analysis of photomultiplier pulses under high loadings is described. To decrease the volume of digit electronics in the converter an analog memory on capacities is envisaged. A well-known bridge circuit with diodes on the main carriers is selected as a gating circuit. The gate control is realized by a switching circuit on fast-response transistors with boundary frequency of 1.2-1.5 GHz. The converter main characteristics are given, namely, maximum output signal amplitude equal to -1.5 V, minimum pulse selection duration of 10 ns, maximum number of counts at Usub(input)=-1.0 V and tsub(selection)=50 ns amounting to 1400, integral nonlinearity of +-0.1%, conversion temperature instability of 0.2%/deg C in the temperature range of (+10-+40) deg C, maximum time of data storage equal to 300 ms, conversion coefficient instability of 0.42 counts, number of channels in a unit CAMAC block equal to 12

  5. Effect of Loading Transients on the EAC Crack Growth Behaviour of Low-Alloy RPV Steels under Simulated BWR Operating Conditions (CASTOC WP 3, PSI Tests 3 and 4)

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, S.; Seifert, H.-P

    2003-04-01

    Within the CASTOC-project (5{sup t}h EU FW programme), the environmentally-assisted crack (EAC) growth behaviour of low-alloy reactor pressure vessel (RPV) steels is experimentally investigated under simulated transient and steady-state boiling water reactor (BWR) power operation conditions by six European laboratories. The present report is a summary of the third and fourth test of working package (WP) 3 with loading transients, performed at Paul Scherrer Institut (PSI). Two different low-alloy steels (20 MnMoNi 5 5, 0.015 wt.% S and 22 NiMoCr 3 7, 0.007 wt. %S) were investigated in oxygenated high-temperature, high-purity water (T = 240 {sup o}C, DO = 400 ppb) in a daisy chain at two different load ratios (R = 0.8 and 0.2). In the first part of the experiments, asymmetrical saw tooth loading with different rise times {delta}t{sub R} of the load and different loading frequencies were applied. Then the loading conditions were changed to an asymmetrical trapezoid waveform loading (periodical partial unloading, PPU) and the hold time {delta}t{sub H} at maximum load was varied. In the final phase of WP 3 PSI tests 3 and 4 the SCC behaviour was investigated under constant load. With decreasing loading frequency the corrosion fatigue (CF) crack advance per cycle {delta}a/{delta}N{sub EAC} of material A increased. Sustained EAC crack growth could be maintained down to low frequencies of 10{sup -5} Hz. The time-based crack growth rate (CGR) da/dt{sub EAC} decreased with decreasing frequency. In material B no effect of the loading frequency could be resolved. Up to a hold time of 1 h at maximum constant load the CGR da/dt{sub EAC} seemed to be independent of the hold time. Above hold times of 1 h the CGR decreased and dropped down to CGR values in the range or below the BWR VIP 60 SCC disposition lines. This behaviour was observed in both investigated materials. The cycle-based CGR {delta}a/{delta}N{sub EAC} remained approximately constant with increasing hold time. The

  6. Distributed Optimization of Sustainable Power Dispatch and Flexible Consumer Loads for Resilient Power Grid Operations

    Science.gov (United States)

    Srikantha, Pirathayini

    Today's electric grid is rapidly evolving to provision for heterogeneous system components (e.g. intermittent generation, electric vehicles, storage devices, etc.) while catering to diverse consumer power demand patterns. In order to accommodate this changing landscape, the widespread integration of cyber communication with physical components can be witnessed in all tenets of the modern power grid. This ubiquitous connectivity provides an elevated level of awareness and decision-making ability to system operators. Moreover, devices that were typically passive in the traditional grid are now `smarter' as these can respond to remote signals, learn about local conditions and even make their own actuation decisions if necessary. These advantages can be leveraged to reap unprecedented long-term benefits that include sustainable, efficient and economical power grid operations. Furthermore, challenges introduced by emerging trends in the grid such as high penetration of distributed energy sources, rising power demands, deregulations and cyber-security concerns due to vulnerabilities in standard communication protocols can be overcome by tapping onto the active nature of modern power grid components. In this thesis, distributed constructs in optimization and game theory are utilized to design the seamless real-time integration of a large number of heterogeneous power components such as distributed energy sources with highly fluctuating generation capacities and flexible power consumers with varying demand patterns to achieve optimal operations across multiple levels of hierarchy in the power grid. Specifically, advanced data acquisition, cloud analytics (such as prediction), control and storage systems are leveraged to promote sustainable and economical grid operations while ensuring that physical network, generation and consumer comfort requirements are met. Moreover, privacy and security considerations are incorporated into the core of the proposed designs and these

  7. Numerical analysis of a downsized spark-ignition engine fueled by butanol/gasoline blends at part-load operation

    International Nuclear Information System (INIS)

    Scala, F.; Galloni, E.; Fontana, G.

    2016-01-01

    Highlights: • Bio-fuels will reduce the overall CO_2 emission. • The properties of butanol/gasoline–air mixtures have been determined. • A 1-D model of a SI engine has been calibrated and validated. • The butanol content reduces the combustion duration. • The optimal ignition timing slightly changes. - Abstract: In this paper, the performance of a turbocharged SI engine, firing with butanol/gasoline blends, has been investigated by means of numerical simulations of the engine behavior. When engine fueling is switched from gasoline to alcohol/gasoline mixture, engine control parameters must be adapted. The main necessary modifications in the Electronic Control Unit have been highlighted in the paper. Numerical analyses have been carried out at partial load operation and at two different engine speeds (3000 and 4000 rpm). Several n-butanol/gasoline mixtures, differing for the alcohol contents, have been analyzed. Such engine performances as torque and indicated efficiency have been evaluated. Both these characteristics decrease with the alcohol contents within the mixtures. On the contrary, when the engine is fueled by neat n-butanol, torque and efficiency reach values about 2% higher than those obtained with neat gasoline. Furthermore, the optimal spark timing, for alcohol/gasoline mixture operation, must be retarded (up to 13%) in comparison with the correspondent values of the gasoline operation. In general, engine performance and operation undergo little variations when fuel supplying is switched from gasoline to alcohol/gasoline blends.

  8. Development of PWR pressure vessel steels

    International Nuclear Information System (INIS)

    Druce, S.; Edwards, B.

    1982-01-01

    Requirements to be met by vessel steels for pressurized water reactors are analyzed. Chemicat composition of low-alloyed steels, mechanical properties of sheets and forgings made of these steels and changes in the composition and properties over the wall thickness of the reactor vessel are presented. Problems of the vessel manufacturing including welding and heat treatment processes of sheets and forgings are considered. Special attention is paid to steel embrittlement during vessel fabrication and operation (radiation embrittlement, thermal embrittlement). The role of non-metal inclusions and their effect on anisotropy of fracture toughness is discussed. Possible developments of vessel steels and procedures for producing reactor vessels are reviewed

  9. Development of PWR pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Druce, S.; Edwards, B.

    1982-01-01

    Requirements to be met by vessel steels for pressurized water reactors are analyzed. Chemicat composition of low-alloyed steels, mechanical properties of sheets and forgings made of these steels and changes in the composition and properties over the wall thickness of the reactor vessel are presented. Problems of the vessel manufacturing including welding and heat treatment processes of sheets and forgings are considered. Special attention is paid to steel embrittlement during vessel fabrication and operation (radiation embrittlement, thermal embrittlement). The role of non-metal inclusions and their effect on anisotropy of fracture toughness is discussed. Possible developments of vessel steels and procedures for producing reactor vessels are reviewed.

  10. Reactor vessel supported by flexure member

    International Nuclear Information System (INIS)

    Crawford, J.D.; Pankow, B.

    1975-01-01

    A description is given of a reactor pressure vessel which is provided with vertical support means in the form of circumferentially spaced columns upon which the vessel is mounted. The columns are adapted to undergo flexure in order to accommodate the thermally induced displacements experienced by the vessel during operational transients

  11. NET in-vessel vehicle system

    International Nuclear Information System (INIS)

    Jones, H.

    1991-02-01

    The CFFTP/Spar In-vessel Vehicle System concept for in-vessel remote maintenance of the NET/ITER machine is described. It comprises a curved deployable boom, a vehicle which can travel on the boom and an end effector or work unit mounted on the vehicle. The stowed boom, vehicle, and work unit are inserted via the equatorial access port of the torus. Following insertion the boom is deployed and locked in place. The vehicle may then travel along the boom to transport the work unit to any desired location. A novel feature of the concept is the deployable boom. When fully deployed, it closely resembles a conventional curved truss structure in configuration and characteristics. However, the joints of the truss structure are hinged so that it can fold into a compact package, of less than 20% of deployed volume for storage, transportation and insertion into the torus. A full-scale 2-metre long section of this boom was produced for demonstration purposes. As part of the concept definition the work unit for divertor handling was studied to demonstrate that large payloads could be manipulated within the confines of the torus using the in-vessel vehicle system. Principal advantages of the IVVS are its high load capacity and rigidity, low weight and stowed volume, simplicity of control and operation, and its relatively high speed of transportation

  12. Early construction and operation of the highly contaminated water treatment system in Fukushima Daiichi Nuclear Power Station (4). Assessment of hydrogen behavior in stored Cs adsorption vessel

    International Nuclear Information System (INIS)

    Kondo, Masahiro; Arai, Takahiro; Nishi, Yoshihisa

    2014-01-01

    Hydrogen diffusion behavior in a cesium adsorption vessel is assessed. The vessel is used to remove radioactive substance from contaminated water, which is proceeded from Fukushima accident. Experiment and numerical calculation are conducted to clarify the characteristics of natural circulation in the vessel. The natural circulation arising from the temperature difference between inside and outside the vessel is confirmed. We develop an evaluation model to predict the natural circulation and its prediction agrees well with the results obtained by the experiment and the calculation. Using the model, we predict steady and transient behavior of hydrogen concentration. Results indicate that hydrogen concentration is kept lower than the flammability limit when the short vent pipe is open. (author)

  13. Performance analyses of a spark-ignition engine firing with gasoline–butanol blends at partial load operation

    International Nuclear Information System (INIS)

    Galloni, E.; Fontana, G.; Staccone, S.; Scala, F.

    2016-01-01

    Highlights: • The potential of butanol has been investigated at partial load operation. • Torque and thermal efficiency slightly decrease when the alcohol content increases. • At part load, spark advance does not require changes when alcohol content increases. - Abstract: Biofuels seem to represent one of the most promising means for the limitation of the greenhouse gas emissions coming from traditional energy systems. In this paper, the performance of a “downsized” spark-ignition engine, fueled by gasoline and bio-butanol blends (20% and 40% butanol mass percentage), has been analyzed. In the first phase of this activity, the experimental tests have been carried out at operating points ranging from low to medium engine speed and load. The first investigations were aimed to assess the main differences among the different fuels in terms of output torque, thermal efficiency, combustion duration and optimal spark timing. In order to study the engine behavior in a wide range of fuel mixtures, these parameters have been evaluated for equivalence ratio values ranging from 1.25 to 0.83. The results obtained in this step show that both the engine torque and thermal efficiency slightly decrease (meanly about 4%) when the blend alcohol content increases. However, butanol increases the burning rate of lean mixtures and an interesting result is that the spark advance does not require adjustments when fueling changes from neat gasoline to bio-butanol/gasoline blends. Later, the pollutant emissions and the CO_2 emissions, for both rich and lean mixtures of pure gasoline and gasoline bio-butanol blends, have been measured. In general, firing with alcohol blends, NO_x and CO emissions remain quite the same, HC emissions slightly decrease while the CO_2 emissions slightly increase. At the end, in order to reproduce the real world urban driving cycle, stoichiometric mixtures have been analyzed. In these conditions, the engine thermal efficiency, at given speed and torque

  14. Recalculation of loads on LOFT penetrations 1A, 2A, 3E, 3F, 5A, 5B, 5C, 5D, 5E, 5F, 7A, 9A, 11C, 17A, 17B, 20A, 20B, 20C, 21A

    International Nuclear Information System (INIS)

    McFadden, D.F.

    1978-01-01

    The loads on the piping nozzles penetrating the LOFT containment vessel are presented. Since the design and construction of the containment vessel, piping systems that penetrate the nozzles have been changed. Consequently, the moments and forces on the containment vessel are different than those stated in LOFT specification S-1. Two combined load cases were tabulated, deadweight plus thermal expansion plus operating basis earthquake and deadweight plus safe shutdown earthquake

  15. Fatigue evaluation in reactor vessel components

    International Nuclear Information System (INIS)

    Mattar Neto, Miguel; Miranda, Carlos A. de J.

    1994-01-01

    This paper presents a sequence of increasing complexity forms of evaluating fatigue damage of nuclear pressure vessel components caused by cycling loadings. Examples are included in order to illustrate such procedures. (author)

  16. Hydraulic nuts (HydraNuts) for reactor vessel tensioning

    International Nuclear Information System (INIS)

    Greenwell, Steve

    2008-01-01

    The paper will present how the introduction of hydraulic nuts - HydraNuts, has reduced critical path times, dose exposure for workers and improved working safety conditions around the reactor vessel during tensioning or de-tensioning operations. It will focus upon detailing the advantages realized by utilities that have introduced the technology and providing examples of the improvements made to the process as well as discussing the engineering design change packages required to make the conversion to the new system. HydraNuts replace the traditional mechanical nut/stud tensioning equipment, combining the two functions into a single system, designed for easy installation and operation by one individual. The primary components of the HydraNut can be assembled without the need for external crane or hoist support and are designed so that each sub assembly can be fitted separately. Once all HydraNuts are fitted to the Rx vessel studs and are sitting on the main Rx vessel head flange, then a system of flexible hydraulic hoses is connected to them, forming a closed loop hydraulic harness, which will allow for simultaneous pressurization of all HydraNuts. Hydraulic pressure is obtained by the use of a hydraulic pumping unit and the resultant load generated in each HydraNut is transferred to the stud and main flange closure is obtained. While maintaining hydraulic pressure, a locking ring is rotated into place on the HydraNut assembly that will support the tensioned load mechanically when the hydraulic pressure is released from the hose harness assembly. The hose harness is removed and the HydraNut is now functioning as a mechanical nut retaining the tensioned load. The HydraNut system for Rx vessel applications was first introduced into a plant in the U.S. in October 2006 and based upon the benefits realized subsequent projects are under way within the Asian and U.S. operating fleet. (author)

  17. Expanded Fermilab pressure vessel directory program

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, A.

    1983-01-01

    Several procedures have been written to manage the information pertaining to the vacuum tanks and pressure vessels for which the laboratory is responsible. These procedures have been named TANK1 for the vessels belonging to the Accelerator Division, TANK2 and TANK3 for the vessels belonging to the Research Division and to Technical Support respectively, and TANK4 for the vessels belonging to the Business Division. The operating procedures are otherwise identical in every respect.

  18. Expanded Fermilab pressure vessel directory program

    International Nuclear Information System (INIS)

    Tanner, A.

    1983-01-01

    Several procedures have been written to manage the information pertaining to the vacuum tanks and pressure vessels for which the laboratory is responsible. These procedures have been named TANK1 for the vessels belonging to the Accelerator Division, TANK2 and TANK3 for the vessels belonging to the Research Division and to Technical Support respectively, and TANK4 for the vessels belonging to the Business Division. The operating procedures are otherwise identical in every respect

  19. 2XIIB vacuum vessel: a unique design

    International Nuclear Information System (INIS)

    Hibbs, S.M.; Calderon, M.O.

    1975-01-01

    The 2XIIB mirror confinement experiment makes unique demands on its vacuum system. The confinement coil set encloses a cavity whose surface is comprised of both simple and compound curves. Within this cavity and at the core of the machine is the operating vacuum which is on the order of 10 -9 Torr. The vacuum container fits inside the cavity, presenting an inside surface suitable for titanium getter pumping and a means of removing the heat load imposed by incandescent sublimator wires. In addition, the cavity is constructed of nonmagnetic and nonconducting materials (nonmetals) to avoid distortion of the pulsed confinement field. It is also isolated from mechanical shocks induced in the machine's main structure when the coils are pulsed. This paper describes the design, construction, and operation of the 2XIIB high-vacuum vessel that has been performing successfully since early 1974

  20. Direct participation of electrical loads in the California independent system operator markets during the Summer of 2000

    International Nuclear Information System (INIS)

    Marnay, Chris; Hamachi, Kristina S.; Khavkin, Mark; Siddiqui, Afzal S.

    2001-01-01

    California's restructured electricity markets opened on 1 April 1998. The former investor-owned utilities were functionally divided into generation, transmission, and distribution activities, all of their gas-fired generating capacity was divested, and the retail market was opened to competition. To ensure that small customers shared in the expected benefit of lower prices, the enabling legislation mandated a 10% rate cut for all customers, which was implemented in a simplistic way that fossilized 1996 tariff structures. Rising fuel and environmental compliance costs, together with a reduced ability to import electricity, numerous plant outages, and exercise of market power by generators drove up wholesale electricity prices steeply in 2000, while retail tariffs remained unchanged. One of the distribution/supply companies entered bankruptcy in April 2001, and another was insolvent. During this period, two sets of interruptible load programs were in place, longstanding ones organized as special tariffs by the distribution/supply companies and hastily established ones run directly by the California Independent System Operator (CAISO). The distribution/supply company programs were effective at reducing load during the summer of 2000, but because of the high frequency of outages required by a system on the brink of failure, customer response declined and many left the tariff. The CAISO programs failed to attract enough participation to make a significant difference to the California supply demand imbalance. The poor performance of direct load participation in California's markets reinforces the argument for accurate pricing of electricity as a stimulus to energy efficiency investment and as a constraint on market volatility

  1. Pressure vessel for nuclear reactors

    International Nuclear Information System (INIS)

    1975-01-01

    The invention applies to a pressure vessel for nuclear reactors whose shell, made of cast metal segments, has a steel liner. This liner must be constructed to withstand all operational stresses and to be easily repairable. The invention solves this problem by installing the liner at a certain distance from the inner wall of the pressure vessel shell and by filling this clearance with supporting concrete. Both the concrete and the steel liner must have a lower prestress than the pressure vessel shell. In order to avoid damage to the liner when prestressing the pressure vessel shell, special connecting elements are provided which consist of welded-on fastening elements projecting into recesses in the cast metal segments of the pressure vessel. Their design is described in detail. (TK) [de

  2. Modeling of a Cogeneration System with a Micro Gas Turbine Operating at Partial Load Conditions

    Directory of Open Access Journals (Sweden)

    José Carlos Dutra

    2017-06-01

    Full Text Available The integration of absorption chillers in micro-cogeneration systems based on micro-gas turbines can be useful as an appropriate strategy to increase the total system energy efficiency. Since it is an area intensive in technology, it is necessary to develop and use models of simulation, which can predict the behavior of the whole system and of each component individually, at different operating conditions. This work is part of a research project in high efficiency cogeneration systems, whose purpose at this stage is to model a micro-cogeneration system, which is composed of a micro gas turbine, Capstone C30, a compact cross flow finned tube heat exchanger and an absorption chiller. The entire model is composed of specifically interconnected models, developed and validated for each component. The simulation of the microturbine used a thermodynamic analytic model, which contains a procedure used to obtain the micro turbine characteristic performance curves, which is closed with the thermodynamic Brayton cycle model. In the cogeneration system discussed in this paper, the compact heat exchanger was used to heat thermal oil, which drives an absorption chiller. It was designed, characterized and installed in a cogeneration system installed at the Centre d'Innovació Tecnològica en Revalorització Energètica i Refrigeració, Universtat Rovira i Virgili. Its design led to the heat exchanger model, which was coupled with the micro turbine model. Presented in this work is a comparison between the data from the model and the experiments, demonstrating good agreement between both results.

  3. Analysis on the Load Carrying Mechanism Integrated as Heterogeneous Co-operative Manipulator in a Walking Wheelchair

    Science.gov (United States)

    Rajay Vedaraj, I. S.; Jain, Ritika; Rao, B. V. A.

    2014-07-01

    After industrial robots came into existence during 1960, the technology of robotics with the design and analysis of robots in various forms in industries as well as in domestic applications were developed. Nowadays, along with the automotive sector the robots are producing a great impact in the form of quality and production rate to register their existence reliable in various other sectors also. Robotic technology has undergone various phase translations from being tortured as humanoids to the present day manipulators. Depending upon the various forms of its existence, robot manipulators are designed as serial manipulators and parallel manipulators. Individually both types can be proved effective though both have various drawbacks in design and the kinematic analysis. The versatility of robots can be increased by making them work in an environment where the same work volume is shared by more than one manipulator. This work volume can be identified as co-operative work volume of those manipulators. Here the interference of manipulators in the work volume of other manipulators is possible and is made obstacle free. The main advantage of co-operative manipulators is that when a number of independent manipulators are put together in a cooperative work envelope the efficiency and ability to perform tasks is greatly enhanced. The main disadvantage of the co-operative manipulators lies in the complication of its design even for a simple application, in almost all fields. In this paper, a cooperative design of robot manipulators to work in co-operative work environment is done and analysed for its efficacy. In the industrial applications when robotic manipulators are put together in more numbers, the trajectory planning becomes the tough task in the work cell. Proper design can remove the design defects of the cooperative manipulators and can be utilized in a more efficient way. In the proposed research paper an analysis is made on such a type of cooperative manipulator

  4. Analysis on the Load Carrying Mechanism Integrated as Heterogeneous Co-operative Manipulator in a Walking Wheelchair

    International Nuclear Information System (INIS)

    Vedaraj, I S Rajay; Jain, Ritika; Rao, B V A

    2014-01-01

    After industrial robots came into existence during 1960, the technology of robotics with the design and analysis of robots in various forms in industries as well as in domestic applications were developed. Nowadays, along with the automotive sector the robots are producing a great impact in the form of quality and production rate to register their existence reliable in various other sectors also. Robotic technology has undergone various phase translations from being tortured as humanoids to the present day manipulators. Depending upon the various forms of its existence, robot manipulators are designed as serial manipulators and parallel manipulators. Individually both types can be proved effective though both have various drawbacks in design and the kinematic analysis. The versatility of robots can be increased by making them work in an environment where the same work volume is shared by more than one manipulator. This work volume can be identified as co-operative work volume of those manipulators. Here the interference of manipulators in the work volume of other manipulators is possible and is made obstacle free. The main advantage of co-operative manipulators is that when a number of independent manipulators are put together in a cooperative work envelope the efficiency and ability to perform tasks is greatly enhanced. The main disadvantage of the co-operative manipulators lies in the complication of its design even for a simple application, in almost all fields. In this paper, a cooperative design of robot manipulators to work in co-operative work environment is done and analysed for its efficacy. In the industrial applications when robotic manipulators are put together in more numbers, the trajectory planning becomes the tough task in the work cell. Proper design can remove the design defects of the cooperative manipulators and can be utilized in a more efficient way. In the proposed research paper an analysis is made on such a type of cooperative manipulator

  5. Benchmarking of multigroup neutron cross sections libraries on neutron transmission through WWER-440 vessel

    International Nuclear Information System (INIS)

    Ilieva, K.; Belousov, S.; Apostolov, T.

    1998-01-01

    The verification of calculated neutron fluence onto the WWER-440/230 pressure vessel is very topical task in particular referring that some of this type of reactors have been operated the major part of its design lifetime. Since the induced activity from the neutron irradiation onto the elements is a simple response of neutron flux the neutron fluence verification usually is done using the measured activity of radionuclides produced during reactor operation. Calculational and experimental results of 54 Mn induced activity of scraps from inner wall of Unit 1 reactor pressure vessel after 18th cycle and detectors irradiated behind the vessel during the 18th cycle of Unit 1 at Kozloduy NPP as well as neutron flux attenuation through the WWER-440/230 pressure vessel are presented. Neutron cross sections libraries generated on the base of ENDF/B-IV and ENDF/B-VI have been used in the calculations. The comparative analysis of evaluated activities and attenuation coefficient demonstrates the better reliability of the neutron fluence calculations by the libraries based on ENDF/B-VI than by ones on ENDF/B-IV. The extreme rarity of data for the activity of scraps from the WWER-440 reactor vessel and its combination with the data for the detectors irradiated behind the vessel makes them especially attractive for verification of calculational methods of neutron fluence onto the WWER-440 vessel with dummy cassettes loading. (author)

  6. Nuclear reactor vessel decontamination systems

    International Nuclear Information System (INIS)

    McGuire, P. J.

    1985-01-01

    There is disclosed in the present application, a decontamination system for reactor vessels. The system is operatable without entry by personnel into the contaminated vessel before the decontamination operation is carried out and comprises an assembly which is introduced into the vertical cylindrical vessel of the typical boiling water reactor through the open top. The assembly includes a circular track which is centered by guideways permanently installed in the reactor vessel and the track guides opposed pairs of nozzles through which water under very high pressure is directed at the wall for progressively cutting and sweeping a tenacious radioactive coating as the nozzles are driven around the track in close proximity to the vessel wall. The whole assembly is hoisted to a level above the top of the vessel by a crane, outboard slides on the assembly brought into engagement with the permanent guideways and the assembly progressively lowered in the vessel as the decontamination operation progresses. The assembly also includes a low pressure nozzle which forms a spray umbrella above the high pressure nozzles to contain radioactive particles dislodged during the decontamination

  7. Study of high load operation limit for premixed compression ignition engine; Yokongo asshuku chakka kikan no kofuka unten genkai ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Shimazaki, N. [Isuzu Advanced Engineering Center Ltd., Kanagawa (Japan); Akagawa, H. [Nissan Diesel Motor Co. Ltd., Saitama (Japan); Tsujimura, K. [Chiba Institute of Technology, Chiba (Japan); Miyamoto, T.

    2000-11-25

    NO{sub x} emission was remarkably reduced by PREDIC (PREmixed lean DIesel Combustion) system in which fuel was injected at very early stage of compression stroke and the major part of the fuel is considered to be burned with self-ignition of premixed charge around TDC. However PREDIC system had some problems, a restriction of a high load operation was one of these problems. In order to investigate the combustion characteristics of PREDIC at the richer operation limit, a test engine was operated with gaseous fuel-air mixture where less heterogeneous mixture can be formed than that of conventional diesel engines. A steep pressure rise or the abrupt increase in NO{sub x} emission determined the richer operation limit. This was at 2 to 2.4 of excess air ratio. Supercharging operation enabled the high load operation more than 2.4 of excess air ratio. (author)

  8. PWR vessel inspection performance improvements

    International Nuclear Information System (INIS)

    Blair Fairbrother, D.; Bodson, Francis

    1998-01-01

    A compact robot for ultrasonic inspection of reactor vessels has been developed that reduces setup logistics and schedule time for mandatory code inspections. Rather than installing a large structure to access the entire weld inspection area from its flange attachment, the compact robot examines welds in overlapping patches from a suction cup anchor to the shell wall. The compact robot size allows two robots to be operated in the vessel simultaneously. This significantly reduces the time required to complete the inspection. Experience to date indicates that time for vessel examinations can be reduced to fewer than four days. (author)

  9. Structural Analysis of the NCSX Vacuum Vessel

    International Nuclear Information System (INIS)

    Fred Dahlgren; Art Brooks; Paul Goranson; Mike Cole; Peter Titus

    2004-01-01

    The NCSX (National Compact Stellarator Experiment) vacuum vessel has a rather unique shape being very closely coupled topologically to the three-fold stellarator symmetry of the plasma it contains. This shape does not permit the use of the common forms of pressure vessel analysis and necessitates the reliance on finite element analysis. The current paper describes the NCSX vacuum vessel stress analysis including external pressure, thermal, and electro-magnetic loading from internal plasma disruptions and bakeout temperatures of up to 400 degrees centigrade. Buckling and dynamic loading conditions are also considered

  10. Power reactor pressure vessel benchmarks

    International Nuclear Information System (INIS)

    Rahn, F.J.

    1978-01-01

    A review is given of the current status of experimental and calculational benchmarks for use in understanding the radiation embrittlement effects in the pressure vessels of operating light water power reactors. The requirements of such benchmarks for application to pressure vessel dosimetry are stated. Recent developments in active and passive neutron detectors sensitive in the ranges of importance to embrittlement studies are summarized and recommendations for improvements in the benchmark are made. (author)

  11. Mooring system for a permanently moored storage vessel at an offshore site

    Energy Technology Data Exchange (ETDEWEB)

    Flory, J.F.

    1983-01-24

    A vessel, e.g. a storage vessel, is permanently moored by means such as a yoke pivoted on the forecastle of the vessel to a mooring leg, e.g. a riser or anchor chain, which is attached to a base located on the ocean floor. Mounted on the vessel are tension, exerting means e.g. counterweights, springs, winches, etc., operably connected with the mooring leg for applying tension e.g. by lifting the yoke. The top of the mooring leg is connected to the end of the yoke through a mooring swivel and gimbaled mooring table or a universal joint. A fluid swivel may be located above the mooring table or about a load-carrying shaft connected to the mooring leg.

  12. Increase of cyclic durability of pressure vessels

    International Nuclear Information System (INIS)

    Vorona, V.A.; Zvezdin, Yu.I.

    1980-01-01

    The durability of multilayer pressure vessels under cyclic loading is compared with single-layer vessels. The relative conditional durability is calculated taking into account the assumption on the consequent destruction of layers and viewing a vessel wall as an indefinite plate. It is established that the durability is mainly determined by the number of layers and to a lesser degree depends on the relative size of the defect for the given layer thickness. The advantage of the multilayer vessels is the possibility of selecting layer materials so that to exclude the effect of agressive corrosion media on the strength [ru

  13. Application of a newly built semi-submersible vessel for transportation of a tension leg platform

    Science.gov (United States)

    Zhang, Dagang; Sun, Weiying; Fan, Zhixia

    2012-09-01

    Transportation of tension leg platform (TLP) structures for a long distance has always been associated with the use of a heavy semi-transport vessel. The requirements of this type of vessel are always special, and their availability is limited. To prepare for the future development of South China Sea deepwater projects, the China Offshore Oil Engineering Corporation has recently built a heavy lift transport vessel-Hai Yang Shi You 278. This semi-submersible vessel has a displacement capacity of 50k DWT, and a breath of 42 meters. Understanding the vessel's applicability and preparing it for use in future deepwater projects are becoming imminent needs. This paper reviews the current critical issues associated with TLP transportation and performs detailed analysis of the designed TLP during load-out and transportation. The newly built COOEC transportation vessel HYSY 278 was applied to dry transport of the TLP structure from the COOEC fabrication yard in Qingdao to an oil field in South China Sea. The entire process included the load-out of the TLP structure from the landsite of the fabrication yard, the offloading and float-on of the platform from the vessel, the dry transport of the TLP over a long distance, and the final offloading of the platform. Both hydrodynamic and structure analysis were performed to evaluate the behavior of the transport vessel and TLP structure. Special attention was paid to critical areas associated with the use of this new vessel, along with any potential limitations. The results demonstrate that HYSY 278 can effectively be used for transporting the structure with proper arrangement and well-prepared operation. The procedure and details were presented on the basis of the study results. Special attention was also given to discussion on future use based on the results from the analysis.

  14. ROSA-V/LSTF vessel top head LOCA tests SB-PV-07 and SB-PV-08 with break sizes of 1.0 and 0.1% and operator recovery actions for core cooling

    International Nuclear Information System (INIS)

    Suzuki, Mitsuhiro; Takeda, Takeshi; Nakamura, Hideo

    2010-02-01

    A series of break size parameter tests (SB-PV-07 and SB-PV-08) were conducted at the Large Scale Test Facility (LSTF) of ROSA-V Program by simulating a vessel top small break loss-of-coolant accident (SBLOCA) at a pressurized water reactor (PWR). Typical phenomena to the vessel top break LOCA and effectiveness of operator recovery actions on core cooling were studied under an assumption of total failure of high pressure injection (HPI) system. The LSTF simulates a 4-loop 3423 MWt PWR by a full-height, full-pressure and 1/48 volume scaling two-loop system. Typical phenomena of vessel top break LOCA are clarified for the cases with break sizes of 1.0 and 0.1% cold leg break equivalent. The results from a 0.5% top break LOCA test (SB-PV-02) in the early ROSA-IV Program was referred during discussion. Operator actions of HPI recovery in the 1.0% top break test and steam generator (SG) depressurization in the 0.1% top break test were initiated when temperature at core exit thermocouple (CET) reached 623 K during core boil-off. Both operator actions resulted in immediate recovery of core cooling. Based on the obtained data, several thermal-hydraulic phenomena were discussed further such as relations between vessel top head water level and steam discharge at the break, and between coolant mass inventory transient and core heat-up and quench behavior, and CET performances to detect core heat-up under influences of three-dimensional (3D) steam flows in the core and core exit. (author)

  15. Impact loads on the pressure vessel top

    International Nuclear Information System (INIS)

    Krieg, R.; Malmberg, T.; Messemer, G.

    1995-01-01

    A steam explosion can cause core melt to be bounced against the internal side of the RPV top. The bouncing velocity up to which the top can withstand the impact is to be determined. Plausible assumptions about a core melt mass of 80000 kg result in a tolerable maximum bouncing velocity of about 200 m/s. Reliable estimates are expected from the BERDA experiments simulating a pessimistic course of events on a 1:10 scale. (orig.)

  16. Containment vessel stability analysis

    International Nuclear Information System (INIS)

    Harstead, G.A.; Morris, N.F.; Unsal, A.I.

    1983-01-01

    The stability analysis for a steel containment shell is presented herein. The containment is a freestanding shell consisting of a vertical cylinder with a hemispherical dome. It is stiffened by large ring stiffeners and relatively small longitudinal stiffeners. The containment vessel is subjected to both static and dynamic loads which can cause buckling. These loads must be combined prior to their use in a stability analysis. The buckling loads were computed with the aid of the ASME Code case N-284 used in conjunction with general purpose computer codes and in-house programs. The equations contained in the Code case were used to compute the knockdown factors due to shell imperfections. After these knockdown factors were applied to the critical stress states determined by freezing the maximum dynamic stresses and combining them with other static stresses, a linear bifurcation analysis was carried out with the aid of the BOSOR4 program. Since the containment shell contained large penetrations, the Code case had to be supplemented by a local buckling analysis of the shell area surrounding the largest penetration. This analysis was carried out with the aid of the NASTRAN program. Although the factor of safety against buckling obtained in this analysis was satisfactory, it is claimed that the use of the Code case knockdown factors are unduly conservative when applied to the analysis of buckling around penetrations. (orig.)

  17. HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT SUMMARY OF COMBINED THERMAL AND OPERATING LOADS WITH SEISMIC ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    MACKEY TC; DEIBLER JE; RINKER MW; JOHNSON KI; ABATT FG; KARRI NK; PILLI SP; STOOPS KL

    2009-01-15

    This report summarizes the results of the Double-Shell Tank Thermal and Operating Loads Analysis (TaLA) combined with the Seismic Analysis. This combined analysis provides a thorough, defensible, and documented analysis that will become a part of the overall analysis of record for the Hanford double-shell tanks (DSTs). The bases of the analytical work presented herein are two ANSYS{reg_sign} finite element models that were developed to represent a bounding-case tank. The TaLA model includes the effects of temperature on material properties, creep, concrete cracking, and various waste and annulus pressure-loading conditions. The seismic model considers the interaction of the tanks with the surrounding soil including a range of soil properties, and the effects of the waste contents during a seismic event. The structural evaluations completed with the representative tank models do not reveal any structural deficiencies with the integrity of the DSTs. The analyses represent 60 years of use, which extends well beyond the current date. In addition, the temperature loads imposed on the model are significantly more severe than any service to date or proposed for the future. Bounding material properties were also selected to provide the most severe combinations. While the focus of the analyses was a bounding-case tank, it was necessary during various evaluations to conduct tank-specific analyses. The primary tank buckling evaluation was carried out on a tank-specific basis because of the sensitivity to waste height, specific gravity, tank wall thickness, and primary tank vapor space vacuum limit. For this analysis, the occurrence of maximum tank vacuum was classified as a service level C, emergency load condition. The only area of potential concern in the analysis was with the buckling evaluation of the AP tank, which showed the current limit on demand of l2-inch water gauge vacuum to exceed the allowable of 10.4 inches. This determination was based on analysis at the

  18. AUTHENTICATION ALGORITHM FOR PARTICIPANTS OF INFORMATION INTEROPERABILITY IN PROCESS OF OPERATING SYSTEM REMOTE LOADING ON THIN CLIENT

    Directory of Open Access Journals (Sweden)

    Y. A. Gatchin

    2016-05-01

    Full Text Available Subject of Research.This paper presents solution of authentication problem for all components of information interoperabilityin process of operation system network loading on thin client from terminal server. System Definition. In the proposed solution operation system integrity check is made by hardware-software module, including USB-token with protected memory for secure storage of cryptographic keys and loader. The key requirement for the solution is mutual authentication of four participants: terminal server, thin client, token and user. We have created two algorithms for the problem solution. The first of the designed algorithms compares the encrypted one-time password (random number with the reference value stored in the memory of the token and updates this number in case of successful authentication. The second algorithm uses the public and private keys of the token and the server. As a result of cryptographic transformation, participants are authenticated and the secure channel is formed between the token, thin client and terminal server. Main Results. Additional research was carried out to find out if the designed algorithms meet the necessary requirements. Criteria used included applicability in a multi-access terminal system architecture, potential threats evaluation and overall system security. According to analysis results, it is recommended to use the algorithm based on PKI due to its high scalability and usability. High level of data security is proved as a result of asymmetric cryptography application with the guarantee that participants' private keys are never sent in the authentication process. Practical Relevance. The designed PKI-based algorithm allows solving the problem with the use of cryptographic algorithms according to state standard even in its absence on asymmetric cryptography. Thus, it can be applied in the State Information Systems with increased requirements to information security.

  19. 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

  20. Design and operational procedures for ORC-based systems coupled with internal combustion engines driving electrical generators at full and partial load

    International Nuclear Information System (INIS)

    Badescu, Viorel; Aboaltabooq, Mahdi Hatf Kadhum; Pop, Horatiu; Apostol, Valentin; Prisecaru, Malina; Prisecaru, Tudor

    2017-01-01

    Highlights: • Waste heat recovery from Internal Combustion Engines (ICEs). • Organic Ranking Cycle (ORC) systems driving Electric Generators (EGs). • ICE-EG partial load operation. • Optimum design geometry of ORC system. • Optimum operation of ORC system at partial EG load. - Abstract: This paper refers to recovering waste heat from the hot gases exhausted by internal combustion engines (ICEs) driving electric generators (EGs) at full and partial load. The topic is of particular interest for developing countries where electric grids are underdeveloped or missing and electricity is generated locally by using classical fuels. The heat recovery system is based on an Organic Rankine Cycle (ORC). A novel method is proposed for the optimum design of ORC-based systems operating in combination with ICE at partial EG loads. First, ORC-based systems coupled with ICEs operating at full EG load is treated. Specific results for the operation at full EG load are as follows: (i) the optimum superheating increment ranges between 30 and 40 °C, depending on the type of the working fluids; (ii) a pinch point temperature difference exits between the flue gas temperature and the working fluid at the evaporator inlet; (iii) the total area of the evaporator is very close to the total area of the condenser, a fact which facilitates manufacturing; (iv) the surface area of the preheater zone is about 75% of the total surface area, while those of the boiler zone and superheater zone is about 13.5% and 11.5%, respectively. Second, the case of the ORC-based systems coupled with ICEs operating at partial EG load is considered. Specific results for this case are as follows: (v) the net power may be maximized by optimizing the working fluid mass flow rate; (vi) when the ICE is coupled with an ORC-based system, the overall thermal efficiency of the combined system, η ICE-ORC , is higher than the thermal efficiency of the ICE operating alone. As an example, for the case treated here,

  1. Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery.

    Science.gov (United States)

    Lewis, Ryan C; Gaffney, Shannon H; Le, Matthew H; Unice, Ken M; Paustenbach, Dennis J

    2012-09-01

    Workers handle catalysts extensively at petroleum refineries throughout the world each year; however, little information is available regarding the airborne concentrations and plausible exposures during this type of work. In this paper, we evaluated the airborne concentrations of 15 metals and total dust generated during solid catalyst loading and unloading operations at one of the largest petroleum refineries in the world using historical industrial hygiene samples collected between 1989 and 2006. The total dust and metals, which included aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, platinum, silicon, silver, vanadium, and zinc, were evaluated in relation to the handling of four different types of solid catalysts associated with three major types of catalytic processes. Consideration was given to the known components of the solid catalysts and any metals that were likely deposited onto them during use. A total of 180 analytical results were included in this analysis, representing 13 personal and 54 area samples. Of the long-term personal samples, airborne concentrations of metals ranged from refinery and perhaps other modern refineries during the timeframe examined. Copyright © 2011 Elsevier GmbH. All rights reserved.

  2. A new approach to control of xenon spatial oscillation during load follow operation via robust servo systems

    International Nuclear Information System (INIS)

    Ukai, Hiroyuki; Iwazumi, Tetsuo

    1994-01-01

    The control problem of xenon-induced spatial oscillations of PWR in the axial direction during a load following operation is investigated. The system models are described by a one-group diffusion equation with xenon and temperature feed-backs, iodine and xenon dynamic equations, and heat conductions processes. Control is implemented by the full-length and the part-length control rods and the boron concentration. In order to achieve the control purpose, control models are formulated as the design problem of robust servo systems for distributed parameter reactor systems. The total thermal power and the axial offset are chosen as outputs to be controlled. The control systems consist of servo compensators and stabilizing compensators. They are designed based on the finite-dimensional systems which are constructed by linearizing around steady states, approximately by the Galerkin method, and reducing dimensions via the singular perturbation method. A new and simple computational algorithm to obtain an approximate solution of a steady-state neutron balance is developed via the perturbation method. Some results of numerical simulations are shown in order to discuss the effectiveness of the theory developed in this paper. In particular, it is shown that the designed servo systems are robust against model errors with linearization and modal truncation

  3. Application of Hybrid Meta-Heuristic Techniques for Optimal Load Shedding Planning and Operation in an Islanded Distribution Network Integrated with Distributed Generation

    Directory of Open Access Journals (Sweden)

    Jafar Jallad

    2018-05-01

    Full Text Available In a radial distribution network integrated with distributed generation (DG, frequency and voltage instability could occur due to grid disconnection, which would result in an islanded network. This paper proposes an optimal load shedding scheme to balance the electricity demand and the generated power of DGs. The integration of the Firefly Algorithm and Particle Swarm Optimization (FAPSO is proposed for the application of the planned load shedding and under frequency load shedding (UFLS scheme. In planning mode, the hybrid optimization maximizes the amount of load remaining and improves the voltage profile of load buses within allowable limits. Moreover, the hybrid optimization can be used in UFLS scheme to identify the optimal combination of loads that need to be shed from a network in operation mode. In order to assess the capabilities of the hybrid optimization, the IEEE 33-bus radial distribution system and part of the Malaysian distribution network with different types of DGs were used. The response of the proposed optimization method in planning and operation were compared with other optimization techniques. The simulation results confirmed the effectiveness of the proposed hybrid optimization in planning mode and demonstrated that the proposed UFLS scheme is quick enough to restore the system frequency without overshooting in less execution time.

  4. Phenomenological vessel burst investigations

    International Nuclear Information System (INIS)

    Hippelein, K.W.; Julisch, P.; Muz, J.; Schiedermaier, J.

    1985-07-01

    Fourteen burst experiments have been carried out using vessels with circumferential and longitudinal flaws, for investigation of the fracture behaviour, i.e. the time-related fracture opening. The vessels had dimensions (outer diameter x wall thickness = 800 x 47 mm) which correspond to the dimensions of the main coolant piping of a 1300 MW e PWR. The test specimens had been made of the base-safe material 20 MnMoNi 55 and of a special, 22 NiMoCr 37 base alloy. The experimental conditions with regard to pressure and temperature have been chosen so as to correspond to normal operating conditions of a PWR (p∝17.5 MPa, T∝300 0 C), i.e. the flaws have been so dimensioned that failure was to be expected at a pressure of p∝17.5 MPa. As a rule, water has been used as the pressure medium, or in some cases air, in order to influence the time-dependent pressure decrease. Fluid and structural dynamics calculations have also been made. In order to determine the impact of a fast propagating crack on the leak-to-fracture curve, which normally is defined by quasistationary experiments, suitable tests have been made with large-volume, cylindrical vessels (outer diameter x wall thickness x length = 3000 x 21 x 14000 mm) made of the material WSt E 43. The leak-before-fracture criterion has been confirmed. (orig./HP) [de

  5. Contrast-enhanced magnetic resonance angiography for the detection of crossing renal vessels in children with symptomatic ureteropelvic junction obstruction: comparison with operative findings.

    Science.gov (United States)

    Calder, Alistair D; Hiorns, Melanie P; Abhyankar, Aruna; Mushtaq, Imran; Olsen, Oystein E

    2007-04-01

    Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management. To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings. We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings. CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively (chi2=14.0; Pchildren older than 6 years with symptomatic UPJ obstruction.

  6. Reactor containment vessel

    International Nuclear Information System (INIS)

    Ochiai, Kanehiro; Hayagumo, Sunao; Morikawa, Matsuo.

    1981-01-01

    Purpose: To safety and simplify the structure in a reactor containment vessel. Constitution: Steam flow channels with steam jetting ports communicating to coolants are provided between a communication channel and coolants in a pressure suppression chamber. Upon loss of coolant accidents, pressure in a dry well will increase, then force downwards water in an annulus portion and further flow out the water through steam jetting ports into a suppression pool. Thus, the steam flow channel is filled with steams or airs present in the dry well, which are released through the steam jetting ports into the pressure suppression chamber. Even though water is violently vibrated owing to the upward movement of air bubbles and condensation of steam bubbles, the annular portion and the steam jetting ports are filled with steams or the like, direct dynamic loads onto the structures such as communication channels can be avoided. (J.P.N.)

  7. Simulation of In-Vessel Corium Retention through External Reactor Vessel Cooling for SMART using SIMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin-Sung; Son, Donggun; Park, Rae-Joon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Thermal load analysis from the corium pool to the outer reactor vessel in the lower plenum of the reactor vessel is necessary to evaluate the effect of the IVR-ERVC during a severe accident for SMART. A computational code called SIMPLE (Sever Invessel Melt Progression in Lower plenum Environment) has been developed for analyze transient behavior of molten corium in the lower plenum, interaction between corium and coolant, and heat-up and ablation of reactor vessel wall. In this study, heat load analysis of the reactor vessel for SMART has been conducted using the SIMPLE. Transient behavior of the molten corium in the lower plenum and IVR-ERVC for SMART has been simulated using SIMPLE. Heat flux from the corium pool to the outer reactor vessel is concentrated in metallic layer by the focusing effect. As a result, metallic layer shows higher temperature than the oxidic layer. Also, vessel wall of metallic layer has been ablated by the high in-vessel temperature. Ex-vessel temperature of the metallic layer was maintained 390 K and vessel thickness was maintained 14 cm. It means that the reactor vessel integrity is maintained by the IVR-ERVC.

  8. Defining the target volume for post-operative radiotherapy after D2 dissection in gastric cancer by CT-based vessel-guided delineation

    International Nuclear Information System (INIS)

    Yoon, Hong In; Chang, Jee Suk; Lim, Joon Seok; Noh, Sung Hoon; Hyung, Woo Jin; An, Ji Yeong; Lee, Yong Chan; Rha, Sun Young; Kim, Kyung Hwan; Koom, Woong Sub

    2013-01-01

    Purpose: To determine the recurrent nodal gross tumor volume (rnGTV) based on CT-guided vascular structure to refine the clinical target volume (CTV) delineation in postoperative radiotherapy for advanced gastric cancer following radical gastrectomy with D2 dissection. Materials and methods: We retrospectively reviewed follow-up images from 91 patients with their first regional recurrence after D2 dissection in stage III gastric cancer with N3 disease. We defined rnGTV as recurrent nodes shown in follow-up CT images, in which one diagnostic radiologist with specialty of gastrointestinal tract investigated. We drew rnGTVs at the equivalent location based on the same vessels of reference comparing CT images to recurrence CT images. Results: We propose vessel-based locations of rnGTVs on CT images with axial and coronal views. We show different patterns of regional recurrence according to the location of primary gastric cancer using CT and digitally reconstructed radiograph (DRR) images. Frequently recurred sites, overlapped by more than five rnGTVs, are depicted in a DRR image. Conclusions: This study suggests vessel-based delineations of rnGTVs on CT images depending on nodal recurrence sites from follow-up images after D2 lymphadenectomy. Our results could help reduce the inter-observer variation of CTV delineation after D2 dissection in gastric cancer

  9. Composite Overwrap Pressure Vessels: Mechanics and Stress Rupture Lifting Philosophy

    Science.gov (United States)

    Thesken, John C.; Murthy, Pappu L. N.; Phoenix, S. L.

    2009-01-01

    The NASA Engineering and Safety Center (NESC) has been conducting an independent technical assessment to address safety concerns related to the known stress rupture failure mode of filament wound pressure vessels in use on Shuttle and the International Space Station. The Shuttle s Kevlar-49 (DuPont) fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar-49 filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of load sharing liners and the complex manufacturing procedures, the state of actual fiber stress in flight hardware and test articles is not clearly known. Indeed nonconservative life predictions have been made where stress rupture data and lifing procedures have ignored the contribution of the liner in favor of applied pressure as the controlling load parameter. With the aid of analytical and finite element results, this paper examines the fundamental mechanical response of composite overwrapped pressure vessels including the influence of elastic plastic liners and degraded/creeping overwrap properties. Graphical methods are presented describing the non-linear relationship of applied pressure to Kevlar-49 fiber stress/strain during manufacturing, operations and burst loadings. These are applied to experimental measurements made on a variety of vessel systems to demonstrate the correct calibration of fiber stress as a function of pressure. Applying this analysis to the actual qualification burst data for Shuttle flight hardware revealed that the nominal fiber stress at burst was in some cases 23 percent lower than what had previously been used to predict stress rupture life. These results motivate a detailed discussion of the appropriate stress rupture lifing philosophy for COPVs including the correct transference of stress rupture life data between dissimilar vessels and test articles.

  10. Composite Overwrap Pressure Vessels: Mechanics and Stress Rupture Lifing Philosophy

    Science.gov (United States)

    Thesken, John C.; Murthy, Pappu L. N.; Phoenix, Leigh

    2007-01-01

    The NASA Engineering and Safety Center (NESC) has been conducting an independent technical assessment to address safety concerns related to the known stress rupture failure mode of filament wound pressure vessels in use on Shuttle and the International Space Station. The Shuttle's Kevlar-49 fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar-49 filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of load sharing liners and the complex manufacturing procedures, the state of actual fiber stress in flight hardware and test articles is not clearly known. Indeed non-conservative life predictions have been made where stress rupture data and lifing procedures have ignored the contribution of the liner in favor of applied pressure as the controlling load parameter. With the aid of analytical and finite element results, this paper examines the fundamental mechanical response of composite overwrapped pressure vessels including the influence of elastic-plastic liners and degraded/creeping overwrap properties. Graphical methods are presented describing the non-linear relationship of applied pressure to Kevlar-49 fiber stress/strain during manufacturing, operations and burst loadings. These are applied to experimental measurements made on a variety of vessel systems to demonstrate the correct calibration of fiber stress as a function of pressure. Applying this analysis to the actual qualification burst data for Shuttle flight hardware revealed that the nominal fiber stress at burst was in some cases 23% lower than what had previously been used to predict stress rupture life. These results motivate a detailed discussion of the appropriate stress rupture lifing philosophy for COPVs including the correct transference of stress rupture life data between dissimilar vessels and test articles.

  11. Pressurized wet digestion in open vessels (T11)

    International Nuclear Information System (INIS)

    Kettisch, P.; Maichin, P.; Zischka, M.; Knapp, G.

    2002-01-01

    Full text: Pressurized wet digestion in closed vessels, microwave assisted or with conventional conductive heating, is the most important sample preparation technique for digestion or leaching procedures in element analysis. In comparison to open vessel digestion closed vessel digestion methods have many advantages, but there is one disadvantage - complex and expensive vessel designs. A new technique - pressurized wet digestion in open vessels - combine the advantages of closed vessel sample digestion with the application of simple and cheap open vessels made of quartz or PFA. The vessels are placed in a high pressure Asher HPA, which is adapted with a Teflon liner and filled partly with water. The analytical results with 30 ml quartz vessels, 22 ml PFA vessels and 1.5 ml PIA auto sampler cups will be shown. In principle every dimensions of vessels can be used. The vessels are loaded with sample material (max. 1.5 g with quartz vessels, max. 0.5 g with PFA vessels and 50 mg with auto sampler cups) and digestion reagent. Afterwards the vessels are simply covered with PTFE stoppers and not sealed. The vessels are transferred into a special adapted HPA and digested at temperatures up to 270 o C. The digestion time is 90 min. and cooling down to room temperature 30 min. The analytical results of CRM's are within the certified values and no cross contamination and losses of volatile elements could be observed. (author)

  12. Modeling of flows in heat exchangers with distributed load loss. Simulation of wet-type cooling tower operation with the two-dimensional calculation code ETHER

    International Nuclear Information System (INIS)

    Coic, P.

    1984-01-01

    The principle of a cooling tower is first presented. The equations of the problem are given; the modeling of load losses and heat transfer is described. Then, the numerical method based on a finite difference discrete method is described. Finally, the different results of the calculations carried out in the case of an industrial operation are presented [fr

  13. Repairing method for shroud in reactor pressure vessel

    International Nuclear Information System (INIS)

    Watanabe, Yusuke.

    1996-01-01

    The present invention provides a method of repairing a shroud disposed in a pressure vessel of a BWR type reactor. Namely, a baffle plate is disposed on the outer surface of the lower portion of the shroud supported by a shroud support of the pressure vessel. The baffle plate is connected with a lug for securing a shroud head bolt disposed on the outer surface of an upper portion of the shroud by reinforcing members. With such a constitution, when crackings are caused in the shroud, the development of the crackings can be prevented without losing the function of securing the shroud head bolt. Further, if a material having thermal expansion coefficient lower than that of austenite stainless steel is used for the material of the reinforcing member, clamping load to be applied upon attaching the auxiliary member can be reduced. As a result, operation for the attachment is facilitated. (I.S.)

  14. The evolution and structural design of prestressed concrete pressure vessels

    International Nuclear Information System (INIS)

    Hannah, I.W.

    1978-01-01

    The introduction of the prestressed concrete pressure vessel to contain the main gas coolant circuit of nuclear reactors has marked a major step forward. This chapter traces the evolution and development of the PCPV, and lists the principal parameters adopted. Current design and loading standards are discussed in relation to the two main limit states of serviceability and safety. Prestressed concrete pressure vessel analysis has called for very extensive adaptation and expansion of conventional finite element and finite difference methods in order to deal with the elevated temperature of operation, together with extensive concrete testing at temperature and under multi-directional stressing. These new methods and extra data are being adopted in prestressed applications in other fields and may well prove to be of much wider significance than is presently appreciated. (author)

  15. Manufacture of EAST VS In-Vessel Coil

    International Nuclear Information System (INIS)

    Long, Feng; Wu, Yu; Du, Shijun; Jin, Huan; Yu, Min; Han, Qiyang; Wan, Jiansheng; Liu, Bin; Qiao, Jingchun; Liu, Xiaochuan; Li, Chang; Cai, Denggang; Tong, Yunhua

    2013-01-01

    Highlights: • ITER like Stainless Steel Mineral Insulation Conductor (SSMIC) used for EAST Tokamak VS In-Vessel Coil manufacture first time. • Research on SSMIC fabrication was introduced in detail. • Two sets totally four single-turn VS coils were manufactured and installed in place symmetrically above and below the mid-plane in the vacuum vessel of EAST. • The manufacture and inspection of the EAST VS coil especially the joint for the SSMIC connection was described in detail. • The insulation resistances of all the VS coils have no significant reduction after endurance test. -- Abstract: In the ongoing latest update round of EAST (Experimental Advanced Superconducting Tokamak), two sets of two single-turn Vertical Stabilization (VS) coils were manufactured and installed symmetrically above and below the mid-plane in the vacuum vessel of EAST. The Stainless Steel Mineral Insulated Conductor (SSMIC) developed for ITER In-Vessel Coils (IVCs) in Institute of Plasma Physics, Chinese Academy of Science (ASIPP) was used for the EAST VS coils manufacture. Each turn poloidal field VS coil includes three internal joints in the vacuum vessel. The middle joint connects two pieces of conductor which together form an R2.3 m arc segment inside the vacuum vessel. The other two joints connect the arc segment with the two feeders near the port along the toroidal direction to bear lower electromagnetic loads during operation. Main processes and tests include material performances checking, conductor fabrication, joint connection and testing, coil forming, insulation performances measurement were described herein

  16. Design and construction of Alborz tokamak vacuum vessel system

    International Nuclear Information System (INIS)

    Mardani, M.; Amrollahi, R.; Koohestani, S.

    2012-01-01

    Highlights: ► The Alborz tokamak is a D-shape cross section tokamak that is under construction in Amirkabir University of Technology. ► As one of the key components for the device, the vacuum vessel can provide ultra-high vacuum and clean environment for the plasma operation. ► A limiter is a solid surface which defines the edge of the plasma and designed to protect the wall from the plasma, localizes the plasma–surface interaction and localizes the particle recycling. ► Structural analyses were confirmed by FEM model for dead weight, vacuum pressure and plasma disruptions loads. - Abstract: The Alborz tokamak is a D-shape cross section tokamak that is under construction in Amirkabir University of Technology. At the heart of the tokamak is the vacuum vessel and limiter which collectively are referred to as the vacuum vessel system. As one of the key components for the device, the vacuum vessel can provide ultra-high vacuum and clean environment for the plasma operation. The VV systems need upper and lower vertical ports, horizontal ports and oblique ports for diagnostics, vacuum pumping, gas puffing, and maintenance accesses. A limiter is a solid surface which defines the edge of the plasma and designed to protect the wall from the plasma, localizes the plasma–surface interaction and localizes the particle recycling. Basic structure analyses were confirmed by FEM model for dead weight, vacuum pressure and plasma disruptions loads. Stresses at general part of the VV body are lower than the structure material allowable stress (117 MPa) and this analysis show that the maximum stresses occur near the gravity support, and is about 98 MPa.

  17. Design features of the KSTAR in-vessel control coils

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.K. [National Fusion Research Institute (NFRI), 52 Yeoeun-dong, Yusung-ku, Daejeon, 305-333 (Korea, Republic of)], E-mail: hkkim@nfri.re.kr; Yang, H.L.; Kim, G.H.; Kim, Jin-Yong; Jhang, Hogun; Bak, J.S.; Lee, G.S. [National Fusion Research Institute (NFRI), 52 Yeoeun-dong, Yusung-ku, Daejeon, 305-333 (Korea, Republic of)

    2009-06-15

    In-vessel control coils (IVCCs) are to be used for the fast plasma position control, field error correction (FEC), and resistive wall mode (RWM) stabilization for the Korea Superconducting Tokamak Advanced Research (KSTAR) device. The IVCC system comprises 16 segments to be unified into a single set to achieve following remarkable engineering advantages; (1) enhancement of the coil system reliability with no welding or brazing works inside the vacuum vessel, (2) simplification in fabrication and installation owing to coils being fabricated outside the vacuum vessel and installed after device assembly, and (3) easy repair and maintenance of the coil system. Each segment is designed in 8 turns coil of 32 mm x 15 mm rectangular oxygen free high conductive copper with a 7 mm diameter internal coolant hole. The conductors are enclosed in 2 mm thick Inconel 625 rectangular welded vacuum jacket with epoxy/glass insulation. Structural analyses were implemented to evaluate structural safety against electromagnetic loads acting on the IVCC for the various operation scenarios using finite element analysis. This paper describes the design features and structural analysis results of the KSTAR in-vessel control coils.

  18. Nonlinear analysis of prestressed concrete reactor pressure vessels

    International Nuclear Information System (INIS)

    Connor, J.J.

    1975-01-01

    The numerical procedures for predicting the nonlinear behavior of a prestressed concrete reactor vessel over its design life are discussed. The numerical models are constructed by combining three-dimensional isoparametric finite elements which simulate the concrete, thin shell elements which simulate steel linear plates, and layers of reinforcement steel, and axial elements for discrete prestressing cables. Nonlinearity under compressive stress, multi-dimensional cracking, shrinkage and stress/temperature induced creep of concrete are considered in addition to the elasti-plastic behavior of the liner and reinforcing steel. Various failure theories for concrete have been proposed recently. Also, there are alternative strategies for solving the discrete system equations over the design life, accounting for test loads, pressure and temperature operational loads, creep unloading and abnormal loads. The proposed methods are reviewed, and a new formulation developed by the authors is described. A number of comparisons with experimental tests results and other numerical schemes are presented. These examples demonstrate the validity of the formulation and also provide valuable information concerning the cost and accuracy of the various solution strategies i.e., total vs. incremental loading and initial vs. tangent stiffness. Finally, the analysis of an actual PCRV is described. Stress contours and cracking patterns in the region of cutouts corresponding to operational pressure and temperature loads are illustrated. The effects of creep, unloading, and creep recovery are then shown. Lastly, a strategy for assessing the performance over its design life is discussed

  19. EDS V25 containment vessel explosive qualification test report.

    Energy Technology Data Exchange (ETDEWEB)

    Rudolphi, John Joseph

    2012-04-01

    The V25 containment vessel was procured by the Project Manager, Non-Stockpile Chemical Materiel (PMNSCM) as a replacement vessel for use on the P2 Explosive Destruction Systems. It is the first EDS vessel to be fabricated under Code Case 2564 of the ASME Boiler and Pressure Vessel Code, which provides rules for the design of impulsively loaded vessels. The explosive rating for the vessel based on the Code Case is nine (9) pounds TNT-equivalent for up to 637 detonations. This limit is an increase from the 4.8 pounds TNT-equivalency rating for previous vessels. This report describes the explosive qualification tests that were performed in the vessel as part of the process for qualifying the vessel for explosive use. The tests consisted of a 11.25 pound TNT equivalent bare charge detonation followed by a 9 pound TNT equivalent detonation.

  20. Simulations of the vortex in the Dellenback abrupt expansion, resembling a hydro turbine draft tube operating at part-load

    International Nuclear Information System (INIS)

    Nilsson, H

    2012-01-01

    This work presents an OpenFOAM case-study, based on the experimental studies of the swirling flow in the abrupt expansion by Dellenback et al.[1]. The case yields similar flow conditions as those of a helical vortex rope in a hydro turbine draft tube working at part-load. The case-study is set up similar to the ERCOFTAC Conical Diffuser and Centrifugal Pump OpenFOAM case-studies [2,3], making all the files available and the results fully reproducable using OpenSource software. The mesh generation is done using m4 scripting and the OpenFOAM built-in blockMesh mesh generator. The swirling inlet boundary condition is specified as an axi-symmetric profile. The outlet boundary condition uses the zeroGradient condition for all variables except for the pressure, which uses the fixed mean value boundary condition. The wall static pressure is probed at a number of locations during the simulations, and post-processing of the time-averaged solution is done using the OpenFOAM sample utility. Gnuplot scripts are provided for plotting the results. The computational results are compared to one of the operating conditions studied by Dellenback, and measurements for all the experimentally studied operating conditions are available in the case-study. Results from five cases are here presented, based on the kEpsilon model, the kOmegaSST model, and a filtered version of the same kOmegaSST model, named kOmegaSSTF [4,5]. Two different inlet boundary conditions are evaluated. It is shown that kEpsilon and kOmegaSST give steady solutions, while kOmegaSSTF gives a highly unsteady solution. The time-averaged solution of the kOmegaSSTF model is much more accurate than the other models. The kEpsilon and kOmegaSST models are thus unable to accurately model the effect of the large-scale unsteadiness, while kOmegaSSTF resolves those scales and models only the smaller scales. The use of two different boundary conditions shows that the boundary conditions are more important than the choice between

  1. Optimizing the Operation of Windfarms, Energy Storage and Flexible Loads in Modern Power Systems and Deregulated Electricity Markets

    Science.gov (United States)

    Dar, Zamiyad

    most turbines is quite close to 1/3 and yaw angle acts as the dominant optimization variable. In the next part of this dissertation, a system comprising of a windfarm and energy storage operating in real-time electricity markets is studied. An Energy-balancing Threshold Price (ETP) policy is proposed to maximize the revenue of a windfarm with on-site storage. We propose and analyze a scheme for a windfarm to store or sell energy based on a threshold price. The threshold price is calculated based on long-term distributions of the electricity price and wind power generation processes, and is chosen so as to balance the energy flows in and out of the storage-equipped windfarm. It is also shown mathematically that the proposed policy is optimal in terms of the long-term revenue generated. Comparing it with the optimal policy that has knowledge of the future, we observe that the revenue obtained by the proposed ETP policy is approximately 90% of the maximum attainable revenue at a storage capacity of 10-15 times the power rating of the windfarm. The intermittent nature of wind power is a hindrance to the efficient participation of windfarms in the day-ahead and forward electricity markets. In this regard, a flexible forward contract is proposed in this dissertation which allows the windfarms to enter into a forward contract with flexible load with an option to deviate from the contracted amount of power. Using such a flexible contract would allow the windfarms to supply more or less than the contracted amount of power in case of unexpected wind conditions or real-time prices. We also propose models for forecasting wind power and real-time electricity prices. The comparison between the proposed contracting framework and a simple fixed contract (currently existing in the market) for different levels of flexibility and load shows that there is a net gain in windfarm revenues, if the transaction price of the two contracts are set equal. Lastly, we present and analyze

  2. A fast-running core prediction model based on neural networks for load-following operations in a soluble boron-free reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin-wook [Korea Atomic Energy Research Institute, P.O. Box 105, Yusong, Daejon 305-600 (Korea, Republic of)], E-mail: Jinwook@kaeri.re.kr; Seong, Seung-Hwan [Korea Atomic Energy Research Institute, P.O. Box 105, Yusong, Daejon 305-600 (Korea, Republic of)], E-mail: shseong@kaeri.re.kr; Lee, Un-Chul [Department of Nuclear Engineering, Seoul National University, Shinlim-Dong, Gwanak-Gu, Seoul 151-742 (Korea, Republic of)

    2007-09-15

    A fast prediction model for load-following operations in a soluble boron-free reactor has been proposed, which can predict the core status when three or more control rod groups are moved at a time. This prediction model consists of two multilayer feedforward neural network models to retrieve the axial offset and the reactivity, and compensation models to compensate for the reactivity and axial offset arising from the xenon transient. The neural network training data were generated by taking various overlaps among the control rod groups into consideration for training the neural network models, and the accuracy of the constructed neural network models was verified. Validation results of predicting load following operations for a soluble boron-free reactor show that this model has a good capability to predict the positions of the control rods for sustaining the criticality of a core during load-following operations to ensure that the tolerable axial offset band is not exceeded and it can provide enough corresponding time for the operators to take the necessary actions to prevent a deviation from the tolerable operating band.

  3. A fast-running core prediction model based on neural networks for load-following operations in a soluble boron-free reactor

    International Nuclear Information System (INIS)

    Jang, Jin-wook; Seong, Seung-Hwan; Lee, Un-Chul

    2007-01-01

    A fast prediction model for load-following operations in a soluble boron-free reactor has been proposed, which can predict the core status when three or more control rod groups are moved at a time. This prediction model consists of two multilayer feedforward neural network models to retrieve the axial offset and the reactivity, and compensation models to compensate for the reactivity and axial offset arising from the xenon transient. The neural network training data were generated by taking various overlaps among the control rod groups into consideration for training the neural network models, and the accuracy of the constructed neural network models was verified. Validation results of predicting load following operations for a soluble boron-free reactor show that this model has a good capability to predict the positions of the control rods for sustaining the criticality of a core during load-following operations to ensure that the tolerable axial offset band is not exceeded and it can provide enough corresponding time for the operators to take the necessary actions to prevent a deviation from the tolerable operating band

  4. Impact of Battery Energy Storage System Operation Strategy on Power System: An Urban Railway Load Case under a Time-of-Use Tariff

    Directory of Open Access Journals (Sweden)

    Hyeongig Kim

    2017-01-01

    Full Text Available Customer-owned battery energy storage systems (BESS have been used to reduce electricity costs of energy storage owners (ESOs under a time-of-use (TOU tariff in Korea. However, the current TOU tariff can unintentionally induce customer’s electricity usage to have a negative impact on power systems. This paper verifies the impact of different BESS operation strategies on power systems under a TOU tariff by analyzing the TOU tariff structure and the customer’s load pattern. First, several BESS operation strategies of ESO are proposed to reduce the electricity cost. In addition, a degradation cost calculation method for lithium ion batteries is considered for the ESO to determine the optimal BESS operation strategy that maximizes both electricity cost and annual investment cost. The optimal BESS operation strategy that maximizes ESO’s net benefit is illustrated by simulation using an urban railway load data from Namgwangju Station, Korea. The results show that BESS connected to urban railway loads can negative impact power system operation. This is due to the high BESS degradation costs and lack of incentive of differential rates in TOU tariff that can effectively induce proper demand response.

  5. Research on the Operation Mode of Intelligent-town Energy Internet Based on Source-Load Interaction

    Science.gov (United States)

    Li, Hao; Li, Wen; Miao, Bo; Li, Bin; Liu, Chang; Lv, Zhipeng

    2018-01-01

    On the background of the rise of intelligence and the increasing deepening of “Internet +”application, the energy internet has become the focus of the energy research field. This paper, based on the fundamental understanding on the energy internet of the intelligent town, discusses the mode of energy supply in the source-load interactive region, and gives an in-depth study on the output characteristics of the energy supply side and the load characteristics of the demand side, so as to derive the law of energy-load interaction of the intelligent-town energy internet.

  6. Contrast-enhanced magnetic resonance angiography for the detection of crossing renal vessels in children with symptomatic ureteropelvic junction obstruction: comparison with operative findings

    Energy Technology Data Exchange (ETDEWEB)

    Calder, Alistair D.; Hiorns, Melanie P.; Olsen, Oystein E. [Hospital for Children NHS Trust, Department of Radiology, London (United Kingdom); Abhyankar, Aruna; Mushtaq, Imran [Hospital for Children NHS Trust, Department of Urology, London (United Kingdom)

    2007-04-15

    Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management. To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings. We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings. CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively ({chi}{sup 2} = 14.0; P < 0.001). In eight of the nine patients with CRV there was no evidence of intrinsic obstruction at surgery. In the remaining patient there was fibrosis of the upper ureter. CE-MRA is an accurate means of identifying CRV in children older than 6 years with symptomatic UPJ obstruction. (orig.)

  7. Contrast-enhanced magnetic resonance angiography for the detection of crossing renal vessels in children with symptomatic ureteropelvic junction obstruction: comparison with operative findings

    International Nuclear Information System (INIS)

    Calder, Alistair D.; Hiorns, Melanie P.; Olsen, Oystein E.; Abhyankar, Aruna; Mushtaq, Imran

    2007-01-01

    Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management. To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings. We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings. CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively (χ 2 = 14.0; P < 0.001). In eight of the nine patients with CRV there was no evidence of intrinsic obstruction at surgery. In the remaining patient there was fibrosis of the upper ureter. CE-MRA is an accurate means of identifying CRV in children older than 6 years with symptomatic UPJ obstruction. (orig.)

  8. Analisa Beban Kerja Operator Inspeksi Dengan Metode Nasa-tlx (Task Load Index) Di PT. Xyz the Workload Analysis of Operator Inspection Using Nasa-tlx (Task Load Index) in PT. Xyz

    OpenAIRE

    Afma, Vera Methalina

    2016-01-01

    Operator packing di PT. XYZ selalu melakukan kegiatan mengangkat dan menurunkan barang seberat 3 kg dan dilakukan 16 kali selama satu hari. Hal ini akan menimbulkan rasa lelah pada operator packing. Di PT. XYZ ada 3 orang operator packing yang melakukan aktivitas yang sama. Penulis tertarik untuk mengetahui dan menganalisa beban kerja operator packing di PT. XYZ dengan pendekatan NASA-TLX. Dari hasil penelitian disimpulkan, beban kerja masing-masing operator packing di PT. XYZ menggunakan me...

  9. The baking analysis for vacuum vessel and plasma facing components of the KSTAR tokamak

    International Nuclear Information System (INIS)

    Lee, K. H.; Woo, H. K.; Im, K. H.; Cho, S. Y.; Kim, J. B.

    2000-01-01

    The base pressure of vacuum vessel of the KSTAR (Korea Superconducting Tokamak Advanced Research) Tokamak is to be a ultra high vacuum, 10 -6 ∼10 -7 Pa, to produce clean plasma with low impurity containments. For this purpose, the KSTAR vacuum vessel and plasma facing components need to be baked up to at least 250 .deg. C, 350 .deg. C respectively, within 24 hours by hot nitrogen gas from a separate baking/cooling line system to remove impurities from the plasma-material interaction surfaces before plasma operation. Here by applying the implicit numerical method to the heat balance equations of the system, overall temperature distributions of the KSTAR vacuum vessel and plasma facing components are obtained during the whole baking process. The model for 2-dimensional baking analysis are segmented into 9 imaginary sectors corresponding to each plasma facing component and has up-down symmetry. Under the resulting combined loads including dead weight, baking gas pressure, vacuum pressure and thermal loads, thermal stresses in the vacuum vessel during bakeout are calculated by using the ANSYS code. It is found that the vacuum vessel and its supports are structurally rigid based on the thermal stress analyses

  10. The baking analysis for vacuum vessel and plasma facing components of the KSTAR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.H. [Chungnam National University Graduate School, Taejeon (Korea); Im, K.H.; Cho, S.Y. [Korea Basic Science Institute, Taejeon (Korea); Kim, J.B. [Hyundai Heavy Industries Co., Ltd. (Korea); Woo, H.K. [Chungnam National University, Taejeon (Korea)

    2000-11-01

    The base pressure of vacuum vessel of the KSTAR (Korea Superconducting Tokamak Advanced Research) Tokamak is to be a ultra high vacuum, 10{sup -6} {approx} 10{sup -7} Pa, to produce clean plasma with low impurity containments. for this purpose, the KSTAR vacuum vessel and plasma facing components need to be baked up to at least 250 deg.C, 350 deg.C respectively, within 24 hours by hot nitrogen gas from a separate baking/cooling line system to remove impurities from the plasma-material interaction surfaces before plasma operation. Here by applying the implicit numerical method to the heat balance equations of the system, overall temperature distributions of the KSTAR vacuum vessel and plasma facing components are obtained during the whole baking process. The model for 2-dimensional baking analysis are segmented into 9 imaginary sectors corresponding to each plasma facing component and has up-down symmetry. Under the resulting combined loads including dead weight, baking gas pressure, vacuum pressure and thermal loads, thermal stresses in the vacuum vessel during bakeout are calculated by using the ANSYS code. It is found that the vacuum vessel and its supports are structurally rigid based on the thermal stress analyses. (author). 9 refs., 11 figs., 1 tab.

  11. The baking analysis for vacuum vessel and plasma facing components of the KSTAR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. H.; Woo, H. K. [Chungnam National Univ., Taejon (Korea, Republic of); Im, K. H.; Cho, S. Y. [korea Basic Science Institute, Taejon (Korea, Republic of); Kim, J. B. [Hyundai Heavy Industries Co., Ltd., Ulsan (Korea, Republic of)

    2000-07-01

    The base pressure of vacuum vessel of the KSTAR (Korea Superconducting Tokamak Advanced Research) Tokamak is to be a ultra high vacuum, 10{sup -6}{approx}10{sup -7}Pa, to produce clean plasma with low impurity containments. For this purpose, the KSTAR vacuum vessel and plasma facing components need to be baked up to at least 250 .deg. C, 350 .deg. C respectively, within 24 hours by hot nitrogen gas from a separate baking/cooling line system to remove impurities from the plasma-material interaction surfaces before plasma operation. Here by applying the implicit numerical method to the heat balance equations of the system, overall temperature distributions of the KSTAR vacuum vessel and plasma facing components are obtained during the whole baking process. The model for 2-dimensional baking analysis are segmented into 9 imaginary sectors corresponding to each plasma facing component and has up-down symmetry. Under the resulting combined loads including dead weight, baking gas pressure, vacuum pressure and thermal loads, thermal stresses in the vacuum vessel during bakeout are calculated by using the ANSYS code. It is found that the vacuum vessel and its supports are structurally rigid based on the thermal stress analyses.

  12. Assuring reliability of unconventional weld joint configurations in austenitic stainless steel pressure vessels through non-destructive examination

    International Nuclear Information System (INIS)

    Jayakumar, I.; Manimohan, M.; Chandrasekaran, G.V.; Abdul Majeeth, S.; Subrahmanyam, P.S.

    1996-01-01

    Design of weld configurations in engineering structures is based on NDE inspectability apart from other considerations. They are mostly standardised. This paper deals with the development of an effective NDE methodology for an unconventional weld joint configuration occurring in a critical pressure vessel with edge preparation orientations different from that normally encountered in fabrication of such vessels. It is K-type butt joint between a heavy load bearing member and a curved vessel wall resulting in an oblique fillet weld. The heavy load bearing functional requirement needs a high integrity fail safe joint during its operating life and the stringent quality level specified by customer was ensured at every stage of its workmanship through effective NDE relying on conventional methods as explained. (author)

  13. ITER vacuum vessel design and electromagnetic analysis on in-vessel components

    International Nuclear Information System (INIS)

    Ioki, K.; Johnson, G.; Shimizu, K.; Williamson, D.; Iizuka, T.

    1995-01-01

    Major functional requirements for the vacuum vessel are to provide the first safety barrier and to support electromagnetic loads due to plasma disruptions and vertical displacement events, and to withstand plausible accidents without losing confinement. A double wall structure concept has been developed for the vacuum vessel due to its beneficial characteristics from the viewpoints of structural integrity and electrical continuity. An electromagnetic analysis of the blanket modules and the vacuum vessel has been performed to investigate force distributions on in-vessel components. According to the vertical displacement events (VDE) scenario, which assumes a critical q-value of 1.5, the total downward vertical force, induced by coupling between the eddy current and external fields, is about 110 MN. We have performed a stress analysis for the vacuum vessel using the VDE disruption forces acting on the blankets, and a maximum stress intensity of 112 MPa was obtained in the vicinity of the lower support of the vessel. (orig.)

  14. Flexible Composite-Material Pressure Vessel

    Science.gov (United States)

    Brown, Glen; Haggard, Roy; Harris, Paul A.

    2003-01-01

    A proposed lightweight pressure vessel would be made of a composite of high-tenacity continuous fibers and a flexible matrix material. The flexibility of this pressure vessel would render it (1) compactly stowable for transport and (2) more able to withstand impacts, relative to lightweight pressure vessels made of rigid composite materials. The vessel would be designed as a structural shell wherein the fibers would be predominantly bias-oriented, the orientations being optimized to make the fibers bear the tensile loads in the structure. Such efficient use of tension-bearing fibers would minimize or eliminate the need for stitching and fill (weft) fibers for strength. The vessel could be fabricated by techniques adapted from filament winding of prior composite-material vessels, perhaps in conjunction with the use of dry film adhesives. In addition to the high-bias main-body substructure described above, the vessel would include a low-bias end substructure to complete coverage and react peak loads. Axial elements would be overlaid to contain damage and to control fiber orientation around side openings. Fiber ring structures would be used as interfaces for connection to ancillary hardware.

  15. Performance of a 2-megawatt high voltage test load

    International Nuclear Information System (INIS)

    Horan, D.; Kustom, R.; Ferguson, M.

    1995-01-01

    A high-power, water-cooled resistive load which simulates the electrical load characteristics of a high-power klystron, capable of 2 megawatts dissipation at 95 kV DC, was built and installed at the Advanced Photon Source for use in load-testing high voltage power supplies. During this testing, the test load has logged approximately 35 hours of operation at power levels in excess of one mezawatt. Slight variations in the resistance of the load during operation indicate that leakage currents in the cooling water may be a significant factor affecting the performance of the load. Sufficient performance data have been collected to indicate that leakage current through the deionized (DI) water coolant shunts roughly 15 percent of the full-load current around the load resistor elements. The leakage current could cause deterioration of internal components of the load. The load pressure vessel was disassembled and inspected internally for any signs of significant wear and distress. Results of this inspection and possible modifications for improved performance will be discussed

  16. Reactor vessel decommissioning project. Final report

    International Nuclear Information System (INIS)

    Schoonen, D.H.

    1984-09-01

    This report describes a reactor vessel decommissioning project; it documents and explains the project objectives, scope, performance results, and sodium removal process. The project was successfully completed in FY-1983, within budget and without significant problems or adverse impact on the environment. Waste generated by the operation included the reactor vessel, drained sodium, and liquid, solid, and gaseous wastes which were significantly less than project estimates. Personnel radiation exposures were minimized, such that the project total was one-half the predicted exposure level. Except for the sodium removed, the material remaining in the reactor vessel is essentially the same as when the vessel arrived for processing

  17. Approaches for accounting and prediction of fast neutron fluence on WWER pressure vessels and results of validation of calculational procedure

    International Nuclear Information System (INIS)

    Borodkin, P.G.; Khrennikov, N.N.; Ryabinin, Yu.A.; Adeev, V.A.

    2015-01-01

    A description is given of the universal procedure for calculation of fast neutron fluence (FNF) on WWER vessels. Approbation of the calculation procedure was carried out by comparing the calculation results for this procedure and measurements on the outer surface of the WWER-440 and WWER-1000 vessels. In addition, an estimation of the uncertainty of the settlement procedure was made in accordance with the requirements of regulatory documents. The developed procedure is applied at Kola NPP for independent fast neutron fluence estimates on the WWER-440 reactor vessels when planning core loads taking into account the introduction of new fuels. The results of the pilot operation of the procedure for calculating FNF at the Kola NPP were taken into account when improving the procedure and its application to the calculations of FNF on the WWER-1000 vessels [ru

  18. Evaluation of trickle-bed air biofilter performance under periodic stressed operating conditions as a function of styrene loading.

    Science.gov (United States)

    Kim, Daekeun; Cai, Zhangli; Sorial, George A

    2005-02-01

    Trickle-bed air biofilters (TBABs) are suitable for treating volatile organic compounds (VOCs) at a significantly high practical loading because of their controlled environmental conditions. The application of TBAB for treating styrene-contaminated air under periodic backwashing and cyclical nonuse periods at a styrene loading of 0.64-3.17 kg chemical oxygen demand (COD)/m3 x day was the main focus of this study. Consistent long-term efficient performance of TBAB strongly depended on biomass control. A periodic in situ upflow with nutrient solution under media fluidization, that is, backwashing, was approached in this study. Two different nonuse periods were employed to simulate a shutdown for equipment repair or during weekends and holidays. The first is a starvation period without styrene loading, and the second is a stagnant period, which reflects no flow passing through the biofilter. For styrene loadings up to 1.9 kg COD/m3 x day, removal efficiencies consistently above 99% were achieved by conducting a coordinated biomass control strategy, that is, backwashing for 1 hr once per week. Under cyclical nonuse periods for styrene loadings up to 1.27 kg COD/m3 x day, stable long-term performance of the biofilter was maintained at more than 99% removal without employing backwashing. No substantial impact of nonuse periods on the biofilter performance was revealed. However, a coordinated biomass control by backwashing subsequently was unavoidable for attaining consistently high removal efficiency at a styrene loading of 3.17 kg COD/m3 x day. As styrene loading was increased, reacclimation of the biofilter to reach the 99% removal efficiency following backwashing or the nonuse periods was delayed. After the non-use periods, the response of the biofilter was a strong function of the biomass in the bed. No significant difference between the effects of the two different nonuse periods on TBAB performance was observed during the study period.

  19. The TPX vacuum vessel and in-vessel components

    International Nuclear Information System (INIS)

    Heitzenroeder, P.; Bialek, J.; Ellis, R.; Kessel, C.; Liew, S.

    1994-01-01

    The Tokamak Physics Experiment (TPX) is a superconducting tokamak with double-null diverters. TPX is designed for 1,000-second discharges with the capability of being upgraded to steady state operation. High neutron yields resulting from the long duration discharges require that special consideration be given to materials and maintainability. A unique feature of the TPX is the use of a low activation, titanium alloy vacuum vessel. Double-wall vessel construction is used since it offers an efficient solution for shielding, bakeout and cooling. Contained within the vacuum vessel are the passive coil system, Plasma Facing Components (PFCs), magnetic diagnostics, and the internal control coils. All PFCs utilize carbon-carbon composites for exposed surfaces

  20. Electrical discharge machining for vessel sample removal

    International Nuclear Information System (INIS)

    Litka, T.J.

    1993-01-01

    Due to aging-related problems or essential metallurgy information (plant-life extension or decommissioning) of nuclear plants, sample removal from vessels may be required as part of an examination. Vessel or cladding samples with cracks may be removed to determine the cause of cracking. Vessel weld samples may be removed to determine the weld metallurgy. In all cases, an engineering analysis must be done prior to sample removal to determine the vessel's integrity upon sample removal. Electrical discharge machining (EDM) is being used for in-vessel nuclear power plant vessel sampling. Machining operations in reactor coolant system (RCS) components must be accomplished while collecting machining chips that could cause damage if they become part of the flow stream. The debris from EDM is a fine talclike particulate (no chips), which can be collected by flushing and filtration

  1. Simple models of district heating systems for load and demand side management and operational optimisation; Simple modeller for fjernvarmesystemer med henblik pae belastningsudjaevning og driftsoptimering

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, B. [Technical Univ. of Denmark, Dept. of Mechanical Engineering, Kgs. Lyngby (Denmark); Larsen, H.V. [Risoe National Lab., System Analysis Dept., Roskilde (DK)

    2004-12-01

    The purpose of this research project has been to further develop and test simple (aggregated) models of district heating (DH) systems for simulation and operational optimization, and to investigate the influence of Load Management and Demand Side Management (DMS) on the total operational costs. The work is based on physical-mathematical modelling and simulation of DH systems, and is a continuation of previous EFP-96 work. In the present EFP-2001 project the goals have been to improve the Danish method of aggregation by addressing the problem of aggregation of pressure losses, and to test the methods on a much larger data set than in the EFP-1996 project. In order to verify the models it is crucial to have good data at disposal. Full information on the heat loads and temperatures not only at the DH plant but also at every consumer (building) is needed, and therefore only a few DH systems in Denmark can supply such data. (BA)

  2. Tar loads on Omani beaches

    International Nuclear Information System (INIS)

    Badawy, M.I.; Al-Harthy, F.T.

    1991-01-01

    Owing to Oman's geographic position and long coastal line, the coastal areas of Oman are particularly vulnerable to oil pollution from normal tanker operations, illegal discharges, and accidental spills as well as local sources of oil input. UNEP carried out a survey on the coasts of Oman to determine the major sources of oil pollution and concluded that the major shoreline pollution problems in Oman arose from operational discharges of oil from passing vessels traffic. The oil, because of the high sea and air temperatures in the area, was subjected to relatively high rates of evaporation and photo-oxidation and tended to arrive at the coast as heavy petroleum particulate residues (tar balls). The aim of the present study was to measure the loads of tar balls in Omani coastal areas and to identify the source of oil pollutants on beaches

  3. Temperature field and thermal stress analysis of the HT-7U vacuum vessel

    International Nuclear Information System (INIS)

    Song Yuntao; Yao Damao; Wu Songtao; Weng Peide

    2000-01-01

    The HT-7U vacuum vessel is an all-metal-welded double-wall interconnected with toroidal and poloidal stiffening ribs. The channels formed between the ribs and walls are filled with boride water as a nuclear shielding. On the vessel surface facing the plasma are installed cable-based Ohmic heaters. Prior to plasma operation the vessel is to be baked out and discharge cleaned at about 250 degree C. During baking out the non-uniformity of temperature distribution on the vacuum vessel will bring about serious thermal stress that can damage the vessel. In order to determine and optimize the design of the HT-7U vacuum vessel, a three-dimensional finite element model was performed to analyse its temperature field and thermal stress. the maximal thermal stress appeared on the round of lower vertical port and maximal deformation located just on the region between the upper vertical port and the horizontal port. The results show that the reinforced structure has a good capability of withstanding the thermal loads

  4. Containment vessel bottom head transport and lifting technique

    International Nuclear Information System (INIS)

    Zheng Donghong; Tian Shiyong; Hu Dequan; Xiao Hongtao

    2013-01-01

    The challengeable transport and lifting techniques and high safety assurance measures are needed for the onsite construction of the AP1000 containment vessel bottom head (CVBH), which is a large component with heavy weight, big size, high center of gravity, and easy to deformation. During transport, the infra structural road foundation is heavily loaded with big turning radius, and the requirement for synchronization of transport vehicles is strict. During lifting, the crane lifting capacities are high, requirement for the lifting and rigging tools is strict, nuclear island being put into place is difficult, and the crane operating foundation is heavily loaded. The transport and lifting techniques and safety assurance measures for CVBH are elaborated in detail, so as to provide a reference for the follow-up transport and lifting of large components of nuclear island. (authors)

  5. Code systems for effective and precise calculation of the basic neutron characteristics, core loading optimization, analysis and estimation of the operation regimes of WWER type reactors

    International Nuclear Information System (INIS)

    Apostolov, T.; Ivanov, K.; Prodanova, R.; Manolova, M.; Petrova, T.; Alekova, G.

    1993-01-01

    Two directions for investigations are suggested: 1) Analysis and evaluation of the real loading patterns and operational regimes for Kozloduy NPP WWER-440 and WWER-1000 in the frame of the recent safety criteria and nuclear power plant operating limits. 2) Development of modern code system for WWER type reactor core analysis with advanced features: new design and materials for fuel and control rods, increasing the fuel enrichment, using the integral and discrete burnable absorbers etc. The fuel technology design evolution maximizes the fuel utilization efficiency, improves operation performance and enhances safety margins. By the joint efforts of specialists from INRNE, Sofia (BG) and KAB, Berlin (GE), the codes NESSEL-IV-EC, PYTHIA and DERAB have been developed and verified. In the frame of the PHARE programme the joint project ASPERCA has been proposed intended for reactor physics calculations with PHYBER-WWER code for safety enhancement and operation reliability improvement. In-core fuel management benchmarks for 4 cycles of unit 2 (WWER-440) and 2 cycles of unit 5 (WWER-1000) have been performed. The coordination of burnable absorber design implementation, low leakage loadings usage, reloading enrichment increase and steel content reduction in the core have made the reactor core analysis more demanding and the definition of loading patterns - more difficult. This complexity requires routine use of three-dimensional fast accurate core model with extended and updated cross section libraries. To meet the needs of WWER advanced loading patterns and in-core fuel management improvements the HEXANES code systems is being developed and qualified. Some test calculations have been carried out by the HEXANES code system investigating the influence of Gd in the fuel on the main reactor physics parameters. For reevaluation of the core safety-related design limits forming the basis of licensing procedure, the code DYN3D/M2 is used. 16 refs., 3 figs. (author)

  6. The impact of microwave stray radiation to in-vessel diagnostic components

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, M.; Laqua, H. P.; Hathiramani, D.; Baldzuhn, J.; Biedermann, C.; Cardella, A.; Erckmann, V.; König, R.; Köppen, M.; Zhang, D. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, D-17489 Greifswald (Germany); Oosterbeek, J.; Brand, H. von der; Parquay, S. [Technische Universiteit Eindhoven, department Technische Natuurkunde, working group for Plasma Physics and Radiation Technology, Den Doelch 2, 5612 AZ Eindhoven (Netherlands); Jimenez, R. [Centro de Investigationes Energeticas, Medioambientales y Technológicas, Association EURATOM/CIEMAT, Avenida Complutense 22, Madrid 28040 (Spain); Collaboration: W7-X Teasm

    2014-08-21

    Microwave stray radiation resulting from unabsorbed multiple reflected ECRH / ECCD beams may cause severe heating of microwave absorbing in-vessel components such as gaskets, bellows, windows, ceramics and cable insulations. In view of long-pulse operation of WENDELSTEIN-7X the MIcrowave STray RAdiation Launch facility, MISTRAL, allows to test in-vessel components in the environment of isotropic 140 GHz microwave radiation at power load of up to 50 kW/m{sup 2} over 30 min. The results show that both, sufficient microwave shielding measures and cooling of all components are mandatory. If shielding/cooling measures of in-vessel diagnostic components are not efficient enough, the level of stray radiation may be (locally) reduced by dedicated absorbing ceramic coatings on cooled structures.

  7. Microbial Population Dynamics and Ecosystem Functions of Anoxic/Aerobic Granular Sludge in Sequencing Batch Reactors Operated at Different Organic Loading Rates

    Directory of Open Access Journals (Sweden)

    Enikö Szabó

    2017-05-01

    Full Text Available The granular sludge process is an effective, low-footprint alternative to conventional activated sludge wastewater treatment. The architecture of the microbial granules allows the co-existence of different functional groups, e.g., nitrifying and denitrifying communities, which permits compact reactor design. However, little is known about the factors influencing community assembly in granular sludge, such as the effects of reactor operation strategies and influent wastewater composition. Here, we analyze the development of the microbiomes in parallel laboratory-scale anoxic/aerobic granular sludge reactors operated at low (0.9 kg m-3d-1, moderate (1.9 kg m-3d-1 and high (3.7 kg m-3d-1 organic loading rates (OLRs and the same ammonium loading rate (0.2 kg NH4-N m-3d-1 for 84 days. Complete removal of organic carbon and ammonium was achieved in all three reactors after start-up, while the nitrogen removal (denitrification efficiency increased with the OLR: 0% at low, 38% at moderate, and 66% at high loading rate. The bacterial communities at different loading rates diverged rapidly after start-up and showed less than 50% similarity after 6 days, and below 40% similarity after 84 days. The three reactor microbiomes were dominated by different genera (mainly Meganema, Thauera, Paracoccus, and Zoogloea, but these genera have similar ecosystem functions of EPS production, denitrification and polyhydroxyalkanoate (PHA storage. Many less abundant but persistent taxa were also detected within these functional groups. The bacterial communities were functionally redundant irrespective of the loading rate applied. At steady-state reactor operation, the identity of the core community members was rather stable, but their relative abundances changed considerably over time. Furthermore, nitrifying bacteria were low in relative abundance and diversity in all reactors, despite their large contribution to nitrogen turnover. The results suggest that the OLR has

  8. The impact of hybrid energy storage on power quality, when high power pulsed DC loads are operated on a microgrid testbed

    Science.gov (United States)

    Kelley, Jay Paul

    As the Navy's demands for high power transient loads evolves, so too does the need for alternative energy sources to back-up the more traditional power generation. Such applications in need of support include electrical grid backup and directed energy weapon systems such as electromagnetic launchers, laser systems, and high power microwave generators, among others. Among the alternative generation sources receiving considerable attention are energy storage devices such as rechargeable electrochemical batteries and capacitors. In such applications as those mentioned above, these energy storage devices offer the ability to serve a dual role as both a power source to the various loads as well high power loads themselves to the continual generation when the high power transient loads are in periods of downtime. With the recent developments in electrochemical energy storage, lithium-ion batteries (LIBs) seem like the obvious choice, but previous research has shown that the elevated rates of charging can be detrimental to both the cycle life and the operational life span of the device. In order to preserve the batteries, their charge rate must be limited. One proposed method to accomplish the dual role task mentioned above, while preserving the life of the batteries, is by combining high energy density LIBs with high power density electric double layer capacitors (EDLCs) or lithium-ion capacitors (LICs) using controllable power electronics to adjust the flow of power to and from each device. Such a configuration is typically referred to as hybrid energy storage module (HESM). While shipboard generators start up, the combined high energy density and high power density of the HESM provides the capability to source critical loads for an extended period of time at the high rates they demand. Once the generator is operationally efficient, the HESM can act as a high energy reservoir to harvest the energy from the generator while the loads are in short periods of inactivity

  9. Conjugate heat transfer analysis for in-vessel retention with external reactor vessel cooling

    International Nuclear Information System (INIS)

    Park, Jong-Woon; Bae, Jae-ho; Song, Hyuk-Jin

    2016-01-01

    Highlights: • A conjugate heat transfer analysis method is applied for in-vessel corium retention. • 3D heat diffusion has a formidable effect in alleviating focusing heat load from metallic layer. • The focusing heat load is decreased by about 2.5 times on the external surface. - Abstract: A conjugate heat transfer analysis method for the thermal integrity of a reactor vessel under external reactor vessel cooling conditions is developed to resolve light metal layer focusing effect issue for in-vessel retention. The method calculates steady-state three-dimensional temperature distribution of a reactor vessel using coupled conjugate heat transfer between in-vessel three-layered stratified corium (metallic pool, oxide pool and heavy metal and polar-angle dependent boiling heat transfer at the outer surface of a reactor vessel). The three-layer corium heat transfer model is utilizing lumped-parameter thermal-resistance circuit method. For the ex-vessel boiling boundary conditions, nucleate, transition and film boiling are considered. The thermal integrity of a reactor vessel is addressed in terms of heat flux at the outer-most nodes of the vessel and remaining thickness profile. The vessel three-dimensional heat conduction is validated against a commercial code. It is found that even though the internal heat flux from the metal layer goes far beyond critical heat flux (CHF) the heat flux from the outermost nodes of the vessel may be maintained below CHF due to massive vessel heat diffusion. The heat diffusion throughout the vessel is more pronounced for relatively low heat generation rate in an oxide pool. Parametric calculations are performed considering thermal conditions such as peak heat flux from a light metal layer, heat generation in an oxide pool and external boiling conditions. The major finding is that the most crucial factor for success of in-vessel retention is not the mass of the molten light metal above the oxide pool but the heat generation rate

  10. Probabilistic retinal vessel segmentation

    Science.gov (United States)

    Wu, Chang-Hua; Agam, Gady

    2007-03-01

    Optic fundus assessment is widely used for diagnosing vascular and non-vascular pathology. Inspection of the retinal vasculature may reveal hypertension, diabetes, arteriosclerosis, cardiovascular disease and stroke. Due to various imaging conditions retinal images may be degraded. Consequently, the enhancement of such images and vessels in them is an important task with direct clinical applications. We propose a novel technique for vessel enhancement in retinal images that is capable of enhancing vessel junctions in addition to linear vessel segments. This is an extension of vessel filters we have previously developed for vessel enhancement in thoracic CT scans. The proposed approach is based on probabilistic models which can discern vessels and junctions. Evaluation shows the proposed filter is better than several known techniques and is comparable to the state of the art when evaluated on a standard dataset. A ridge-based vessel tracking process is applied on the enhanced image to demonstrate the effectiveness of the enhancement filter.

  11. Gigacycle fatigue behaviour of austenitic stainless steels used for mercury target vessels

    International Nuclear Information System (INIS)

    Naoe, Takashi; Xiong, Zhihong; Futakawa, Masatoshi

    2016-01-01

    A mercury enclosure vessel for the pulsed spallation neutron source manufactured from a type 316L austenitic stainless steel, a so-called target vessel, suffers the cyclic loading caused by the proton beam induced pressure waves. A design criteria of the JSNS target vessel which is defined based on the irradiation damage is 2500 h at 1 MW with a repetition rate of 25 Hz, that is, the target vessel suffers approximately 10 9 cyclic loading while in operation. Furthermore, strain rate of the beam window of the target vessel reaches 50 s −1 at the maximum, which is much higher than that of the conventional fatigue. Gigacycle fatigue strength up to 10 9 cycles for solution annealed 316L (SA) and cold-worked 316L (CW) were investigated through the ultrasonic fatigue tests. Fatigue tests were performed under room temperature and 250 °C which is the maximum temperature evaluated at the beam window in order to investigate the effect of temperature on fatigue strength of SA and CW 316L. The results showed that the fatigue strength at 250 °C is clearly reduced in comparison with room temperature, regardless of cold work level. In addition, residual strength and microhardness of the fatigue tested specimen were measured to investigate the change in mechanical properties by cyclic loading. Cyclic hardening was observed in both the SA and CW 316L, and cyclic softening was observed in the initial stage of cyclic loading in CW 316L. Furthermore, abrupt temperature rising just before fatigue failure was observed regardless of testing conditions.

  12. Improvement to reactor vessel

    International Nuclear Information System (INIS)

    1974-01-01

    The vessel described includes a prestressed concrete vessel containing a chamber and a removable cover closing this chamber. The cover is in concrete and is kept in its closed position by main and auxiliary retainers, comprising fittings integral with the concrete of the vessel. The auxiliary retainers pass through the concrete of the cover. This improvement may be applied to BWR, PWR and LMFBR type reactor vessel [fr

  13. ALICE HMPID Radiator Vessel

    CERN Document Server

    2003-01-01

    View of the radiator vessels of the ALICE/HMPID mounted on the support frame. Each HMPID module is equipped with 3 indipendent radiator vessels made out of neoceram and fused silica (quartz) windows glued together. The spacers inside the vessel are needed to stand the hydrostatic pressure. http://alice-hmpid.web.cern.ch/alice-hmpid

  14. Indoor air bacterial load and antibiotic susceptibility pattern of isolates in operating rooms and surgical wards at jimma university specialized hospital, southwest ethiopia.

    Science.gov (United States)

    Genet, Chalachew; Kibru, Gebre; Tsegaye, Wondewosen

    2011-03-01

    Surgical site infection is the second most common health care associated infection. One of the risk factors for such infection is bacterial contamination of operating rooms' and surgical wards' indoor air. In view of that, the microbiological quality of air can be considered as a mirror of the hygienic condition of these rooms. Thus, the objective of this study was to determine the bacterial load and antibiotic susceptibility pattern of isolates in operating rooms' and surgical wards' indoor air of Jimma University Specialized Hospital. A cross sectional study was conducted to measure indoor air microbial quality of operating rooms and surgical wards from October to January 2009/2010 on 108 indoor air samples collected in twelve rounds using purposive sampling technique by Settle Plate Method (Passive Air Sampling following 1/1/1 Schedule). Sample processing and antimicrobial susceptibility testing were done following standard bacteriological techniques. The data was analyzed using SPSS version 16 and interpreted according to scientifically determined baseline values initially suggested by Fisher. The mean aerobic colony counts obtained in OR-1(46cfu/hr) and OR-2(28cfu/hr) was far beyond the set 5-8cfu/hr acceptable standards for passive room. Similarly the highest mean aerobic colony counts of 465cfu/hr and 461cfu/hr were observed in Female room-1 and room-2 respectively when compared to the acceptable range of 250-450cfu/hr. In this study only 3 isolates of S. pyogenes and 48 isolates of S. aureus were identified. Over 66% of S. aureus was identified in Critical Zone of Operating rooms. All isolates of S. aureus showed 100% and 82.8% resistance to methicillin and ampicillin respectively. Higher degree of aerobic bacterial load was measured from operating rooms' and surgical wards' indoor air. Reducing foot trafficking, improving the ventilation system and routine cleaning has to be made to maintain the aerobic bacteria load with in optimal level.

  15. Strength and durability tests of pipeline supports for the areas of above-ground routing under the influence of operational loads

    Directory of Open Access Journals (Sweden)

    Surikov Vitaliy Ivanovich

    2014-03-01

    Full Text Available The present article deals with integrated research works and tests of pipeline supports for the areas of above-ground routing of the pipeline system “Zapolyarye - Pur-pe” which is laid in the eternally frozen grounds. In order to ensure the above-ground routing method for the oil pipeline “Zapolyarye - Pur-pe” and in view of the lack of construction experience in case of above-ground routing of oil pipelines, the leading research institute of JSC “Transneft” - LLC “NII TNN” over the period of August, 2011 - September, 2012 performed a research and development work on the subject “Development and production of pipeline supports and pile foundation test specimens for the areas of above-ground routing of the pipeline system “Zapolyarye - Pur-pe”. In the course of the works, the test specimens of fixed support, linear-sliding and free-sliding pipeline supports DN1000 and DN800 were produced and examined. For ensuring the stable structural reliability of the supports constructions and operational integrity of the pipelines the complex research works and tests were performed: 1. Cyclic tests of structural elements of the fixed support on the test bed of JSC “Diascan” by means of internal pressure and bending moment with the application of specially prepared equipment for defining the pipeline supports strength and durability. 2. Tests of the fixed support under the influence of limit operating loads and by means of internal pressure for confirming the support’s integrity. On the test bed there were simulated all the maximum loads on the support (vertical, longitudinal, side loadings, bending moment including subsidence of the neighboring sliding support and, simultaneously, internal pressure of the carried medium. 3. Cyclic tests of endurance and stability of the displacements of sliding supports under the influence of limit operating loads for confirming their operation capacity. Relocation of the pipeline on the sliding

  16. BY FRUSTUM CONFINING VESSEL

    Directory of Open Access Journals (Sweden)

    Javad Khazaei

    2016-09-01

    Full Text Available Helical piles are environmentally friendly and economical deep foundations that, due to environmental considerations, are excellent additions to a variety of deep foundation alternatives available to the practitioner. Helical piles performance depends on soil properties, the pile geometry and soil-pile interaction. Helical piles can be a proper alternative in sensitive environmental sites if their bearing capacity is sufficient to support applied loads. The failure capacity of helical piles in this study was measured via an experimental research program that was carried out by Frustum Confining Vessel (FCV. FCV is a frustum chamber by approximately linear increase in vertical and lateral stresses along depth from top to bottom. Due to special geometry and applied bottom pressure, this apparatus is a proper choice to test small model piles which can simulate field stress conditions. Small scale helical piles are made with either single helix or more helixes and installed in fine grained sand with three various densities. Axial loading tests including compression and tension tests were performed to achieve pile ultimate capacity. The results indicate the helical piles behavior depends essentially on pile geometric characteristics, i.e. helix configuration and soil properties. According to the achievements, axial uplift capacity of helical model piles is about equal to usual steel model piles that have the helixes diameter. Helical pile compression bearing capacity is too sufficient to act as a medium pile, thus it can be substituted other piles in special geoenvironmental conditions. The bearing capacity also depends on spacing ratio, S/D, and helixes diameter.

  17. Autonomic adjusting of activity of cardio-vessel system of girls of the prepubescence period, engaged in dancing aerobic

    Directory of Open Access Journals (Sweden)

    Romanchuk А.P.

    2010-03-01

    Full Text Available The vegetative adjusting of activity of the cardio-vessel system of girls is investigational. In an experiment took part girls of 9-12 years old. A type of sport is a dancing aerobics. The indexes of general power of spectrum of variability of cardiac rhythm are presented, systole and diastole arteriotony. Motion of the adaptation re-erecting is appraised under influence of the physical loadings in the conditions of current and operative control. Certain change activity and tone of vegetative influences on the cardio-vessel system. They determine the features of the further adaptation re-erecting in an organism.

  18. 46 CFR 169.689 - Demand loads.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Demand loads. 169.689 Section 169.689 Shipping COAST... Electrical Electrical Installations on Vessels of 100 Gross Tons and Over § 169.689 Demand loads. Demand loads must meet § 111.60-7 of this chapter except that smaller demand loads for motor feeders are...

  19. Sealing method and sealing device for radioactive waste containing vessel

    International Nuclear Information System (INIS)

    Ishiwatari, Koji; Otsuki, Akira

    1998-01-01

    A radioactive waste-containing body is hoisted down into a strong-material vessel opened upwardly, and a strong-material lid is hoisted down to the opening of the strong-material-vessel and welded. The strong material vessel is hoisted up and loaded on a corrosion resistant-material bottom plate placed horizontally. A corrosion resistant-material vessel having one opening end and having a corrosion resistant-material flange on the other end and previously agreed with the strong material-vessel main body is hoisted up by a hoisting device having an inserting device so that the opening of the corrosion resistant vessel is directed downwardly. The corrosion resistant vessel is press-fitted to the outside of the strong material-vessel by the inserting device while being heated by a preheater to shrink. Subsequently, the lower end of the corrosion resistant-material vessel and the corrosion resistant-material bottom plate are welded to constitute a corrosion resistant-material vessel. Then, the radioactive waste containing body can be sealed in a sealing vessel comprising the strong-material vessel and the corrosion resistant-material vessel. (N.H.)

  20. Load curves analysis under operational and economics focus; Analise de curvas de carga sob enfoques operativos e economicos

    Energy Technology Data Exchange (ETDEWEB)

    Matos, R S; Cardoso, A F; Fleury, M E.V. [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)

    1988-12-31

    This work aims to present the analysis of load curves performed by the short term planning sectors of several subsidiaries, independently of the methodologies used. In order to do so some peculiar occurrences were selected which show the influence of factors that are external to the electric power system. In such way, the analysis of past situations proves to be an important tool in the forecasting work so that a better planning may be achieved. 13 figs., 2 tabs.