WorldWideScience

Sample records for building outage frp

  1. Bruce B 2004 vacuum building outage: fiberglass spray header refurbishment program

    International Nuclear Information System (INIS)

    Bruce Power is required to inspect the internals of the containment system Vacuum Building at the Bruce B plant once every 12 years and the previous inspection was carried out in 1992. During the 2004 Bruce B Vacuum Building Outage (VBO) significant inspections and refurbishment were carried out on the dousing water system spray headers which are a key component of the post- LOCA Vacuum Building pressure suppression system. These sixteen headers are made of Fiberglass Reinforced Plastic (FRP) and were manufactured by Tywood Industries in 1980. The company went out of business shortly after supplying the headers and the resin and roving used to manufacture the headers is no longer available. There were several known manufacturing deficiencies with the spray headers and degradation with aging was expected to have occurred. Inconsistent results from laboratory assessments of aged samples created considerable uncertainty as to the current condition of the headers. To remove and replace entire spray headers would be a very complicated and time-consuming process due to the physical access difficulties. Each new header would have to be brought into the vacuum building in pieces and assembled in situ. Header replacement was not considered a viable alternative for the 2004 VBO so plans were put in place to refurbish the headers sufficiently to ensure that they would last at least until the next planned inspection in 2016. This FRP spray header inspection and rehabilitation program was the critical path job for the 2004 VBO. This paper will summarize the technical concerns and uncertainties with the integrity of the FRP spray headers that existed prior to the outage but will primarily focus on the preparations for, execution of, and lessons learned during the actual field execution of the work. (author)

  2. Power Outages

    Science.gov (United States)

    ... Thunderstorms & Lightning Tornadoes Tsunamis Volcanoes Wildfires Main Content Power Outages This page provides basic safety tips and ... during and after a power outage. Before a Power Outage Build or restock your emergency preparedness kit , ...

  3. Power Outages

    Science.gov (United States)

    ... Plants Workplace Plans School Emergency Plans Main Content Power Outages This page provides basic safety tips and ... during and after a power outage. Before a Power Outage Build or restock your emergency preparedness kit , ...

  4. FRP rupture strains in FRP wrapped columns

    OpenAIRE

    Li, Shiqing

    2012-01-01

    Applying lateral confinement to concrete columns using fibre-reinforced polymer (FRP) composites is a very promising technique. FRP rupture is the typical failure mode of FRP wrapped columns under axial compression. numerous experiments have shown that the FRP rupture strain in an FRP wrapped circular column is significantly lower than the FRP ultimate rupture strain determined from flat coupon test of FRP. Despite a large number of studies on the application of FRP confined columns, the mech...

  5. CONTRIBUTION TO THE POTENTIAL OF USING FRP MATERIALS IN THE REHABILITATION AND STABILIZATION OF TIMBERED BUILDINGS

    Directory of Open Access Journals (Sweden)

    Tomáš Čejka

    2015-12-01

    Full Text Available Wooden log, timbered perimeter and interior walls ranked among the most common building constructions used from the Early Middle Ages. In most cases, the local natural resources, i.e. wood, clay, straw and stone, were used for building houses with wooden framing. This article outlines typical defects and failures of timbered houses, “classic” techniques for the rehabilitation of these defects and failures indicating the potential of using composite materials based on high- strength fibres and epoxy resin in the rehabilitation and strengthening of timbered buildings.

  6. A Novel Structural Assessment Technique to Prevent Damaged FRP-Wrapped Concrete Bridge Piers from Collapse

    OpenAIRE

    Buyukozturk, Oral; Yu, Tzu-Yang

    2009-01-01

    Repairing deteriorated concrete bridge piers using externally wrapped fiber reinforced polymer (FRP) composites have been proven as an effective approach. This technique has also been applied to low-rise building structures. Failures in FRP-wrapped concrete structures may occur by flexural failures of critical sections or by debonding of FRP plate from the concrete substrate. Debonding in the FRP/adhesive/concrete interface region may cause a significant decrease in member capacity leading to...

  7. FRP : Strengthened RC Structures

    Science.gov (United States)

    Teng, J. G.; Chen, J. F.; Smith, S. T.; Lam, L.

    2002-01-01

    The strengthening of reinforced concrete (RC) structures using advanced fibre-reinforced polymer (FRP) composites, and in particular the behaviour of FRP-strengthened RC structures is a topic which has become very popular in recent years. This popularity has arisen due to the need to maintain and upgrade essential infrastructure in all parts of the world, combined with the well-known advantages of FRP composites, such as good corrosion resistance and ease for site handling due to their light weight. The continuous reduction in the material cost of FRP composites has also contributed to their popularity. While a great amount of research now exists in the published literature on this topic, it is scattered in various journals and conference proceedings. This book therefore provides the first ever comprehensive, state-of-the-art summary of the existing research on FRP strengthening of RC structures, with the emphasis being on structural behaviour and strength models. The main topics covered include: Bond behaviour Flexural and shear strengthening of beams Column strengthening Flexural strengthening of slabs. For each area, the methods of strengthening are discussed, followed by a description of behaviour and failure modes and then the presentation of rational design recommendations, for direct use in practical design of FRP strengthening measures. Researchers, practicing engineers, code writers and postgraduate students in structural engineering and construction materials, as well as consulting firms, government departments, professional bodies, contracting firms and FRP material suppliers will find this an invaluable resource.

  8. Facility Response Plan (FRP)

    Data.gov (United States)

    U.S. Environmental Protection Agency — A Facility Response Plan (FRP) demonstrates a facility's preparedness to respond to a worst case oil discharge. Under the Clean Water Act, as amended by the Oil...

  9. Architectural engineering of FRP bridges

    OpenAIRE

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on architectural application of FRP's derived from the authors architectural practice.

  10. Darlington NGS vacuum building outage: modification to supply post-seismic makeup water to the heat transport system

    International Nuclear Information System (INIS)

    The periodic stationwide outage at Darlington NGS includes removal of the Emergency Coolant Injection System from service to allow for maintenance. As a prerequisite, the station must set up a minimum 2.5 kg/s temporary makeup water supply, to help cool the fuel should a seismic event occur. This modification cannot be commissioned, as commissioning would dilute the heavy water in the Primary Heat Transport System with light water. Therefore, flow analysis is necessary to demonstrate that the required flow rate can be achieved. This paper provides details of the design, and key aspects of the supporting analysis. (author)

  11. Darlington NGS vacuum building outage: modification to supply post-seismic makeup water to the heat transport system

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.; Dean, B.; Emad, M. [Wardrop Engineering Inc., Energy Div., Pickering, Ontario (Canada)

    2009-07-01

    The periodic stationwide outage at Darlington NGS includes removal of the Emergency Coolant Injection System from service to allow for maintenance. As a prerequisite, the station must set up a minimum 2.5 kg/s temporary makeup water supply, to help cool the fuel should a seismic event occur. This modification cannot be commissioned, as commissioning would dilute the heavy water in the Primary Heat Transport System with light water. Therefore, flow analysis is necessary to demonstrate that the required flow rate can be achieved. This paper provides details of the design, and key aspects of the supporting analysis. (author)

  12. REPAIR AND STRENGTHENING OF REINFORCED CONCRETE BEAMS USING FIBRE REINFORCED POLIMER (FRP) MATERIALS

    OpenAIRE

    ÇETİNKAYA, Nihat; Kaplan, Hasan; Ş. Murat ŞENEL

    2004-01-01

    The use of Fibre Reinforced Polimer (FRP ) materials for the repair and strengthening of Reinforced Concrete structures has become widespread recently. FRP materials are being prefered because they have very high tensile strength, resistance to corrosion and they do not affect the use of the building during the repair and strengthening process. Four reinfoced concrete beams repaired and strengthened with FRP materials have been used in this study which were performed at Pamukkale University-F...

  13. Paper on outage philosophy

    International Nuclear Information System (INIS)

    After a brief history of outages in the Scottish nuclear power plants, the author comments the different pressures contributing to a change in the management and the organisation of these outages. He comments the outage organisation (in terms of management, use of station work force, company support, open communications, career development), the outage philosophy (in terms of supportive management, teamwork and total quality management, ownership and commitment to safety, good preparation and robust planning, achievable and agreed targets, process analysis and continual improvement), outage achievements (in terms of time between breakers, work efficiency, safety), the future improvements. He identifies the recipe for success

  14. FRP tendon anchorage in post-tensioned concrete structures

    DEFF Research Database (Denmark)

    Schmidt, Jacob Wittrup; Täljsten, Björn; Bennitz, Anders; Henning, Pedersen

    Strengthening of building structures by the use of various external post-tensioning steel tendon systems, is known to be a very efficient method. However, FRP as material in external post-tensioning projects has been investigated during the last decade. The advantages for this material are the high...

  15. FRP tendon anchorage in post-tensioned concrete structures

    DEFF Research Database (Denmark)

    Schmidt, Jacob Wittrup; Täljsten, Björn; Bennitz, Anders; Henning, Pedersen

    Strengthening of building structures by the use of various external post-tensioning steel tendon systems, is known to be a very efficient method. However, FRP as material in external post-tensioning projects has been investigated during the last decade. The advantages for this material are the high...... effective Young´s modulus and the high stress capacity in the linear elastic range of the material. The use of external tendons increases the requirements on the anchorage systems. This is in particular important when using un-bonded tendon systems, where the anchorage and deviators are the only force...... transfer points. The demand for high capacity anchorage tendons is fulfilled for steel tendons, but no competitive mechanical anchor has yet been developed for FRP tendon. A new small, reliable and more user friendly anchor has to be developed, before FRP tendons can be utilized with all of its capacity...

  16. Nuclear power plant outages

    International Nuclear Information System (INIS)

    The Finnish Radiation and Nuclear Safety Authority (STUK) controls nuclear power plant safety in Finland. In addition to controlling the design, construction and operation of nuclear power plants, STUK also controls refuelling and repair outages at the plants. According to section 9 of the Nuclear Energy Act (990/87), it shall be the licence-holder's obligation to ensure the safety of the use of nuclear energy. Requirements applicable to the licence-holder as regards the assurance of outage safety are presented in this guide. STUK's regulatory control activities pertaining to outages are also described

  17. FRP-to-concrete joint assemblies anchored with multiple FRP anchors: experimental investigation

    OpenAIRE

    Zhang, H.; Smith, ST

    2010-01-01

    Higher strains can be developed in fibre-reinforced polymer (FRP) composites which are bonded to the surfaces of concrete members if the FRP is anchored. Anchors made from FRP (also known as FRP spike anchors but herein referred to as FRP anchors) are a promising type of anchorage as they can be applied to a variety of different shaped structural elements and they have been shown to be effective in en-hancing the strain capacity of externally bonded FRP. Limited research, however, has been co...

  18. Outage preparation milestones - A tool to improve planned outage performance

    International Nuclear Information System (INIS)

    Sustainable development of Nuclear Energy depends heavily on excellent performance of the existing fleet which in turn depend heavily on the performance of planned outages. Nuclear Power Plants who have successfully undertaken outage optimization projects have demonstrated than an effective Outage Preparation Milestone program is a key component of their improvement programs. This paper will provide background into the field of 'Outage Optimization' including the philosophy, general approach, and results obtained in the U. S. industry. The significant safety improvements afforded by properly implementing outage improvement programs will be explained. Some specific examples of outage improvements will be given including the adoption of a strong Outage Preparation Milestone Program. The paper will then describe the attributes of an effective Outage Preparation Milestone Program and list a set of specific key milestones. The key milestones are defined and the reasons for each are explained. Suggested due dates for each key milestone relative to the outage start date are provided. Successful implementation of an Outage Preparation Milestone program depends heavily upon the management tools and methods used to assure that the organization meets the milestones on time and in a quality fashion. These include methods to handle cases where milestones are not met - either partially or fully. KHNP is investigating implementing an improved Outage Preparation Milestone program for its fleet of reactors as part of its overall program to improve its performance of planned outages

  19. Design guidelines for FRP reinforced concrete structures

    OpenAIRE

    Pilakoutas, Kypros; Guadagnini, Maurizio; Neocleous, Kyriacos; Matthys, Stijn

    2011-01-01

    This paper presents an outline of the approach proposed by fib task group 9.3 for the next generation of design guidelines for fibre-reinforced polymer (FRP) reinforced concrete structures. The approach covers a range of FRP-related topics, including material properties, durability, design philosophy, the limit states of bending, shear, cracking and deflection, and bond.

  20. Refuelling outage optimization

    International Nuclear Information System (INIS)

    The Teollisuuden Voima Oy (TVO) operates two 710 MW nuclear power plant units in Olkiluoto on the west coast of Finland. TVO I was connected to the national grid in 1978 and TVO II in 1980. The price of the produced electricity is depending on the capacity factor of the plant. In order to avoid unplanned shutdowns and to operate at a high efficiency a good condition monitoring and an effective maintenance are needed. In this paper the development of the main maintenance period of the plant and the refuelling outage are described. (author). 11 figs

  1. Strategies for organizing outages

    International Nuclear Information System (INIS)

    Based on four sociological studies carried out in France and in the United States between 1991 and 1994, this paper aims at presenting different organizational strategies for scheduled outages in nuclear power plants. Some short examples suggest that organizational settings are not equivalent in terms of actors' practices: some organizational designs tend to minimize actors autonomy while others are favouring it. Distinctions can also be made between formal and informal autonomy or between clear delegations of decision making power and implicit ones. The author argues that these differences have major implications for actors' participation inside the organization

  2. Influence of FRP anchors on FRP-to-concrete bonder interfaces

    OpenAIRE

    Zhang, Huawen; 张华文

    2013-01-01

    Existing reinforced concrete (RC) structural members such as beams, columns and joints can be strengthened and repaired with externally bonded high-strength and light-weight fibre-reinforced polymer (FRP) composites. The effectiveness of such strengthening can, however, be limited by premature debonding of the FRP at strains well below the strain capacity of the FRP. Such failures are also generally sudden and give rise to brittle member behavour. It is therefore important to prevent or even...

  3. Outage management and health physics issue, 2009

    International Nuclear Information System (INIS)

    The focus of the May-June issue is on outage management and health physics. Major articles include the following: Planning and scheduling to minimize refueling outage, by Pat McKenna, AmerenUE; Prioritizing safety, quality and schedule, by Tom Sharkey, Dominion; Benchmarking to high standards, by Margie Jepson, Energy Nuclear; Benchmarking against U.S. standards, by Magnox North, United Kingdom; Enabling suppliers for new build activity, by Marcus Harrington, GE Hitachi Nuclear Energy; Identifying, cultivating and qualifying suppliers, by Thomas E. Silva, AREVA NP; Creating new U.S. jobs, by Francois Martineau, Areva NP. Industry innovation articles include: MSL Acoustic source load reduction, by Amir Shahkarami, Exelon Nuclear; Dual Methodology NDE of CRDM nozzles, by Michael Stark, Dominion Nuclear; and Electronic circuit board testing, by James Amundsen, FirstEnergy Nuclear Operating Company. The plant profile article is titled The future is now, by Julia Milstead, Progress Energy Service Company, LLC

  4. Region 9 Facility Response Plan (FRP) - 2014

    Data.gov (United States)

    U.S. Environmental Protection Agency — A Facility Response Plan (FRP) demonstrates a facility's preparedness to respond to a worst case oil discharge. Under the Clean Water Act, as amended by the Oil...

  5. Nuclear Plant Integrated Outage Management

    International Nuclear Information System (INIS)

    This paper is a discussion of an emerging concept for improving nuclear plant outage performance - integrated outage management. The paper begins with an explanation of what the concept encompasses, including a scope definition of the service and descriptions of the organization structure, various team functions, and vendor/customer relationships. The evolvement of traditional base scope services to the integrated outage concept is addressed and includes discussions on changing customer needs, shared risks, and a partnership approach to outages. Experiences with concept implementation from a single service in 1984 to the current volume of integrated outage management presented in this paper. We at Westinghouse believe that the operators of nuclear power plants will continue to be aggressively challenged in the next decade to improve the operating and financial performance of their units. More and more customers in the U. S. are looking towards integrated outage as the way to meet these challenges of the 1990s, an arrangement that is best implemented through a long-term partnering with a single-source supplier of high quality nuclear and turbine generator outage services. This availability, and other important parameters

  6. RECENT DEVELOPMENTS IN FRP STRENGTHENING TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    Zhishen WU(吴智深); Hedong Niu

    2004-01-01

    This paper mainly gives a State-of-the-Art report of recent development in FRP strengthening techniques for structural rehabilitation by starting with a brief review on some achievements in clarifying bonding/debonding mechanisms and developing evaluation/design methodology for predicting debonding failure caused by intermedioate flexural cracks of con crete.Due to some drawbacks of current FRP bonding technique,two effective FRP strengthening methods,i.e.FRP prestressing and hybrid strengthening techniques,are investigated in detail to make full advantage of FRP composite materials.Combining with the newly develiped PBO fiber sheets,a more effective prestressing method is established as compared with carbon fiber sheets,a more effective prestressing method is established as compared with carbon fiber sheets,where several anchorage treatments are also established to prevent anchorage bond failure due to high shear stress concentration after release of prestressed FRP ends.In addition,the fatigue performance of RC beams externally strenghened with prestressed PBO fiber sheets is experimentally studied.For the developments of hybrid composites and their strengthening methods,both experimental and analytical studies are performed to clarify the hybrid strengthening behavior in structures.

  7. Outage rates and outage durations of opportunistic relaying systems

    CERN Document Server

    Hadzi-Velkov, Zoran; 10.1109/LCOMM.2010.02.091683

    2010-01-01

    Opportunistic relaying is a simple yet efficient cooperation scheme that achieves full diversity and preserves the spectral efficiency among the spatially distributed stations. However, the stations' mobility causes temporal correlation of the system's capacity outage events, which gives rise to its important second-order outage statistical parameters, such as the average outage rate (AOR) and the average outage duration (AOD). This letter presents exact analytical expressions for the AOR and the AOD of an opportunistic relaying system, which employs a mobile source and a mobile destination (without a direct path), and an arbitrary number of (fixed-gain amplify-and-forward or decode-and-forward) mobile relays in Rayleigh fading environment.

  8. FIRE PROTECTION OF TIMBER STRUCTURES STRENGTHENED WITH FRP MATERIALS

    Directory of Open Access Journals (Sweden)

    Radek Zigler

    2015-12-01

    Full Text Available Modern, progressive methods of structures’ strengthening based on the use of composite materials composed of high strength fibers (carbon, glass, aramid or basalt and matrices based on epoxy resins brings, among many indisputable advantages (low weight, high effectiveness, easy application etc. also some disadvantages. One of the major disadvantages is a low fire resistance of these materials due to the low glass transition temperature Tg of the resin used. Based on an extensive research of strengthening of historic structures with FRP materials [1], the article outlines possible approaches to this problem, especially while strengthening timber load- bearing structures of historic buildings.

  9. 35/30 outage improvement project

    International Nuclear Information System (INIS)

    Outage performance is a significant contributor to the business plan at Bruce Power. A process improvement initiative commenced in 2010-11 to improve outage efficiency and predictability. 12 teams (over 200 people) participated in improvement identification in four areas: Organizational Engagement; Outage Scope; Resources; and, Critical Outage Execution. Out of over 550 initiatives identified, 200 are being incorporated into the Outage Improvement Initiative. Key deliverables include: Development of a long-range 'fleet-level' business strategy to integrate outage duration, outage improvements and unit refurbishments; Development of a 35 day outage schedule template; Determining optimal outage organization to perform outages on an 8-unit site; Improved schedule adherence and productivity; Process to integrate scope needs to support life-cycle and long-range outage needs improvement while meeting near term and regulatory requirements; Consistent methodology in planning of outages to front-end load the high risk work into the outage schedule; Consistent baseline by senior leaders for the expectations of milestone ownership and completion; Consistent framework for milestone compliance and preparation; Communication strategy to educate personnel on the importance of the outage program and nuclear safety, business goals, and budget; and, Suite of metrics based upon industry benchmarks. The Outage Improvement Initiative has a goal of 35 day outages every 30 months. This potentially represents considerable savings to the Bruce Power business plan, both direct revenue savings attributed to reduced outage duration, as well as incremental outage cost savings. Other improvements from the initiative will include personnel radiation exposure and equipment reliability due to decreased outage duration and adherence to scoping, assessing and long lead part milestones. This presentation will describe the outage improvement initiatives to achieve a goal of consistent 35 day outages

  10. FRP resin process automating system; FRP jushi kako jidoka system

    Energy Technology Data Exchange (ETDEWEB)

    Ochiai, I.; Sakai, H. [Meidensha Corp., Tokyo (Japan)

    1994-10-18

    This paper introduces as FRP resin product processing system using robots. Automatic processing by means of robots requires considerations on positioning of delivered workpieces, correction of positional shift of workpieces, monitoring of tools and cutters, disposal of chips, and dust and noise preventive measures. In a bath tank drilling and deburring system, robots should measure and correct the positional shift of workpieces, exchange tools automatically, and shut down the system upon occurrence of anomaly in processing. The wall panel processing system performs transportation of products by using a lift and carry system in consideration of preventing nicks on the transportation side a product. Workpiece positioning is performed by lifting and pressing them onto the standard plate on the upper portion of panel, and the thickness and length are measured and corrected by a workpiece shift correcting sensor disposed on a robot. The purification tank partition drilling system has shuttle-type transportation devices installed on both flanks of a robot. This is a high-efficiency system requiring no robot downtime. A dust collecting duct is disposed below the positioning device to prevent chips from leaking outside the device. 4 figs., 7 tabs.

  11. Improvements in D2O leakage detection in restricted areas of Reactor Building during operation and tritium in air monitoring during outages

    International Nuclear Information System (INIS)

    This report describes the air sampling lines required for the improvement of simultaneous sampling for tritium in air monitoring in restricted areas of Reactor Building during operation. These sampling lines require penetrations equipped with containment sealing solenoid valves. It also describes the equipment used and the experience gained from some D2O leakages since Plant commissioning. By taking into account the current tendencies, improvements in gathering all data related to tritium concentrations in Reactor Building in Health Physicist's office, room S - 307 were made. Air samples were analyzed either by a liquid scintillation detector and/or by a proportional counter simultaneously, instead of the former single samples. These improvements also gave the possibility of a quicker detection of D2O leakage, thus contributing to keep low personnel dose, according to ALARA principles, as 'in situ' monitoring have proved to be not justifiable. (authors)

  12. Global Loads on FRP Ship Hulls

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    1997-01-01

    Fibre reinforced plastic (FRP) composites used for high-speed vessels have lower modulus of elasticity than the conventionally used steels.Therefore, for large fast ships the lowest natural frequencies of the global hull modes can be relatively low compared to the frequency of waveencounter. As...... part of the NoKoS project it was decided to investigate the effect of hull flexibility on the wave-induced as well as accidental structural loads on high-speed ships.Especially it was decided to determine whether there is an upper size of FRP and aluminium mono-hulls caused by continuous wave action...

  13. Outage management: A case study

    International Nuclear Information System (INIS)

    Outage management issues identified from a field study conducted at a two-unit commercial pressurized water reactor (PWR), when one unit was in a refueling outage and the other unit was at full power operation, are the focus of this paper. The study was conduced as part of the US Nuclear Regulatory Commission's (NRC) organizational factors research program, and therefore the issues to be addressed are from an organizational perspective. Topics discussed refer to areas identified by the NRC as critical for safety during shutdown operations, including outage planning and control, personnel stress, and improvements in training and procedures. Specifically, issues in communication, management attention, involvement and oversight, administrative processes, organizational culture, and human resources relevant to each of the areas are highlighted by example from field data collection. Insights regarding future guidance in these areas are presented based upon additional data collection subsequent to the original study

  14. Outage management: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Haber, S.B.; Barriere, M.T. (Brookhaven National Lab., Upton, NY (United States)); Roberts, K.H. (California Univ., Berkeley, CA (United States). Walter A. Haas School of Business)

    1992-01-01

    Outage management issues identified from a field study conducted at a two-unit commercial pressurized water reactor (PWR), when one unit was in a refueling outage and the other unit was at full power operation, are the focus of this paper. The study was conduced as part of the US Nuclear Regulatory Commission's (NRC) organizational factors research program, and therefore the issues to be addressed are from an organizational perspective. Topics discussed refer to areas identified by the NRC as critical for safety during shutdown operations, including outage planning and control, personnel stress, and improvements in training and procedures. Specifically, issues in communication, management attention, involvement and oversight, administrative processes, organizational culture, and human resources relevant to each of the areas are highlighted by example from field data collection. Insights regarding future guidance in these areas are presented based upon additional data collection subsequent to the original study.

  15. Outage management: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Haber, S.B.; Barriere, M.T. [Brookhaven National Lab., Upton, NY (United States); Roberts, K.H. [California Univ., Berkeley, CA (United States). Walter A. Haas School of Business

    1992-09-01

    Outage management issues identified from a field study conducted at a two-unit commercial pressurized water reactor (PWR), when one unit was in a refueling outage and the other unit was at full power operation, are the focus of this paper. The study was conduced as part of the US Nuclear Regulatory Commission`s (NRC) organizational factors research program, and therefore the issues to be addressed are from an organizational perspective. Topics discussed refer to areas identified by the NRC as critical for safety during shutdown operations, including outage planning and control, personnel stress, and improvements in training and procedures. Specifically, issues in communication, management attention, involvement and oversight, administrative processes, organizational culture, and human resources relevant to each of the areas are highlighted by example from field data collection. Insights regarding future guidance in these areas are presented based upon additional data collection subsequent to the original study.

  16. Power Outage - 16 October

    CERN Multimedia

    2014-01-01

    At 19:03 last night, a fire in an 18kV circuit breaker in building 212 led to a blackout on the Meyrin site. The CERN fire brigade rapidly brought the fire under control and power was restored by 22:25. Many CERN systems were affected and have been brought back in to service overnight, this work will continue through the day.

  17. Improving refueling outages through partnership

    International Nuclear Information System (INIS)

    This paper describes an approach to reduce nuclear plant outage duration and cost through partnership. Partnership is defined as a long-term commitment between the utility and the vendor with the objective of achieving shared business goals by maximizing the effectiveness of each party's resources. The elements of an effective partnership are described. Specific examples are given as to how partnership has worked in the effective performance of refueling outages. To gain the full benefits of a partnership, both parties must agree to share information, define the scope early, communicate goals and expectations, and identify boundaries for technical ownership. (author)

  18. Exceptional outage for Fessenheim-1

    International Nuclear Information System (INIS)

    The article describes the 10-yearly outage maintenance and improvements program during the 191-day shut-down of Fessenheim on the Grand Canal d'Alsace. The program concerns hydraulic and containment testing as well as specialized maintenance operations on heavy-duty components

  19. Minimizing forced outage risk in generator bidding

    Science.gov (United States)

    Das, Dibyendu

    Competition in power markets has exposed the participating companies to physical and financial uncertainties. Generator companies bid to supply power in a day-ahead market. Once their bids are accepted by the ISO they are bound to supply power. A random outage after acceptance of bids forces a generator to buy power from the expensive real-time hourly spot market and sell to the ISO at the set day-ahead market clearing price, incurring losses. A risk management technique is developed to assess this financial risk associated with forced outages of generators and then minimize it. This work presents a risk assessment module which measures the financial risk of generators bidding in an open market for different bidding scenarios. The day-ahead power market auction is modeled using a Unit Commitment algorithm and a combination of Normal and Cauchy distributions generate the real time hourly spot market. Risk profiles are derived and VaRs are calculated at 98 percent confidence level as a measure of financial risk. Risk Profiles and VaRs help the generators to analyze the forced outage risk and different factors affecting it. The VaRs and the estimated total earning for different bidding scenarios are used to develop a risk minimization module. This module will develop a bidding strategy of the generator company such that its estimated total earning is maximized keeping the VaR below a tolerable limit. This general framework of a risk management technique for the generating companies bidding in competitive day-ahead market can also help them in decisions related to building new generators.

  20. Outage capacity of multicarrier systems

    KAUST Repository

    Yilmaz, Ferkan

    2010-01-01

    The probability density function and the cumulative distribution function of the product of shifted Gamma variates are obtained in terms of the generalized Fox\\'s H function. Using these new results, the exact outage capacity of multi carrier transmission through a slow Nakagami-m fading channel is presented. Moreover, it is shown that analytical and simulation results are in perfect agreement. © 2009 IEEE.

  1. FRP-to-concrete bond behaviour under high strain rates

    OpenAIRE

    Li, Xiaoqin

    2012-01-01

    Fibre reinforced polymer (FRP) composites have been used for strengthening concrete structures since early 1990s. More recently, FRP has been used for retrofitting concrete structures for high energy events such as impact and blast. Debonding at the FRP-to-concrete interface is one of the predominant failure modes for both static and dynamic loading. Although extensive research has been conducted on the static bond behaviour, the bond-slip mechanics under high strain rates is n...

  2. Limit analysis on FRP-strengthened RC members

    OpenAIRE

    D. De Domenico; A.A.Pisano; P. Fuschi

    2014-01-01

    Reinforced concrete (RC) members strengthened with externally bonded fiber-reinforced-polymer (FRP) plates are numerically investigated by a plasticity-based limit analysis approach. The key-concept of the present approach is to adopt proper constitutive models for concrete, steel reinforcement bars (re-bars) and FRP strengthening plates according to a multi-yield-criteria formulation. This allows the prediction of concrete crushing, steel bars yielding and FRP rupture that may oc...

  3. Darlington Station outage - a maintenance perspective

    International Nuclear Information System (INIS)

    Ontario Hydro's Darlington Nuclear Generating Station (4x881MW(e)net) has carried out its first station outage since full commercial operation. The outage presented challenges to the organization in terms of outage planning, support, management, and safe execution within the constraints of schedule, budget and resources. This paper will focus on the success of the outage maintenance program, identifying the major work programs - a vacuum structure and containment outage, an emergency service water system outage, an emergency coolant injection system outage, intake channel inspections, low pressure service water inspections, and significant outage maintenance work on each of the four reactor units. Planning for the outage was initiated early in anticipation of this important milestone in the station's life. Detailed safety reviews - nuclear, radiation, and conventional - were conducted in support of the planned maintenance program. System lineup and work protection were provided by the Station Operator work group. Work protection permitry was initiated well in advance of the outage. Station maintenance staff resources were bolstered in support of the outage to ensure program execution could be maintained within the schedule. Training programs were in place to ensure that expectations were clear and that high standards would be maintained. Materials management issues in support of maintenance activities were given high priority to ensure no delays to the planned work. Station management review and monitoring in preparation for and during the outage ensured that staff priorities remained focused. Lessons learned from the outage execution are being formalized in maintenance procedures and outage management procedures, and shared with the nuclear community. (author)

  4. Shear Strengthening Performance of Hybrid FRP-FRCM

    Directory of Open Access Journals (Sweden)

    Kyusan Jung

    2015-01-01

    Full Text Available The effectiveness of a hybrid fiber reinforced polymer- (FRP- fabric reinforced cementitious matrix (FRCM for shear strengthening was investigated though an experimental study. FRP materials of FRCM are usually fabricated in the form of a fabric to enhance the bond strength between the FRP material and the cementitious matrix. The hybrid FRP fabric used in this study consisted of carbon FRP (CFRP and glass FRP (GFRP in warp and weft directions, respectively. A total of 11 beams were fabricated and 8 beams among them were strengthened in shear with externally bonded hybrid FRP-FRCM. The number of plies, the bond types, and the spacing of the hybrid FRP fabric were considered as experimental variables. Additionally, a shear capacity model for a FRCM shear strengthened beam was proposed. The values predicted by the proposed model were compared with those by the ACI 549 code and test results. It was confirmed from the comparison that the proposed model predicted the shear strengthening performance of the hybrid FRP-FRCM more reliably than the ACI 549 code did.

  5. Superelastic SMA–FRP composite reinforcement for concrete structures

    International Nuclear Information System (INIS)

    For many years there has been interest in using fiber-reinforced polymers (FRPs) as reinforcement in concrete structures. Unfortunately, due to their linear elastic behavior, FRP reinforcing bars are never considered for structural damping or dynamic applications. With the aim of improving the ductility and damping capability of concrete structures reinforced with FRP reinforcement, this paper studies the application of SMA–FRP, a relatively novel type of composite reinforced with superelastic shape memory alloy (SMA) wires. The cyclic tensile behavior of SMA–FRP composites are studied experimentally and analytically. Tests of SMA–FRP composite coupons are conducted to determine their constitutive behavior. The experimental results are used to develop and calibrate a uniaxial SMA–FRP analytical model. Parametric and case studies are performed to determine the efficacy of the SMA–FRP reinforcement in concrete structures and the key factors governing its behavior. The results show significant potential for SMA–FRP reinforcement to improve the ductility and damping of concrete structures while still maintaining its elastic characteristic, typical of FRP reinforcement

  6. Nuclear power plant outage optimisation strategy

    International Nuclear Information System (INIS)

    Competitive environment for electricity generation has significant implications for nuclear power plant operations, including among others the need of efficient use of resources, effective management of plant activities such as on-line maintenance and outages. Nuclear power plant outage management is a key factor for good, safe and economic nuclear power plant performance which involves many aspects: plant policy, co-ordination of available resources, nuclear safety, regulatory and technical requirements and, all activities and work hazards, before and during the outage. This technical publication aims to communicate these practices in a way they can be used by operators and utilities in the Member States of the IAEA. It intends to give guidance to outage managers, operating staff and to the local industry on planning aspects, as well as examples and strategies experienced from current plants in operation on the optimization of outage period. This report discusses the plant outage strategy and how this strategy is actually implemented. The main areas identified as most important for outage optimization by the utilities and government organizations participating in this report are: organization and management; outage planning and preparation, outage execution, safety outage review, and counter measures to avoid extension of outages and to easier the work in forced outages. This report was based on discussions and findings by the authors of the annexes and the participants of an Advisory Group Meeting on Determinant Causes for Reducing Outage Duration held in June 1999 in Vienna. The report presents the consensus of these experts regarding best common or individual good practices that can be used at nuclear power plants with the aim to optimize

  7. Reengineering to reduce outage costs: Spring hanger pinning during outages

    International Nuclear Information System (INIS)

    One of the key steps in the reengineering process requires us to ask the question, open-quotes Is this step in our work process necessary?close quotes This paper describes one such redesign of a maintenance procedure, resulting in significant gains in cost reduction and schedule compression for plant outages. Before draining a water-filled piping system, maintenance procedures at many power plants require pinning of all spring hangers supporting the system. This requirement ensures that piping system components are not overloaded by the spring force that is no longer counteracted by the weight of water in the pipeline. Unfortunately, pinning spring hangers can be a time-consuming and costly endeavor. Because spring hangers quite often are located in congested areas that are inaccessible from floor level, scaffolding must be erected to allow physical access by maintenance personnel. At Clinton power station, the subject power plant for this paper, this activity was costing approximately $250 000 per refueling outage and a personnel radiation exposure of -5 person-rems. In the past, the only alternative to this costly requirement was to perform case-by-case analysis to evaluate the effects of the spring uplift forces on the drained piping and associated components. However, these analyses are costly (approximately $8000 per piping subsystem) and time consuming. Given these rather significant costs, it is highly advantageous to limit or eliminate the spring hanger pinning requirement. This paper presents an overview of an evaluation performed for Clinton power station to address this issue

  8. Achieving outage excellence through partnership in performance

    International Nuclear Information System (INIS)

    This paper discusses the joint efforts of Public Service of New Jersey and Westinghouse aimed at attaining excellence in outage performance. Success in the 1986 outages at Salem Units 1 and 2 was accomplished by joint efforts in detailed initial communication and planning, tough goal setting, communication of objectives, identification of responsibility, incentive structuring, and finally, by hard work by both organizations aimed at working the plan and minimizing impacts where changes were required during the outage

  9. Management of planned unit outages

    International Nuclear Information System (INIS)

    Management of planned unit outages at the Bruno Leuschner Nuclear Power Plant is based on the experience gained with Soviet PWR units of the WWER type over a period of more than 50 reactor-years. For PWR units, planned outages concentrate almost exclusively on annual refuellings and major maintenance of the power plant facilities involved. Planning of such major maintenance work is based on a standardized basic network plan and a catalogue of standardized maintenance and inspection measures. From these, an overall maintenance schedule of the unit and partial process plans of the individual main components are derived (manually or by computer) and, in the temporal integration of major maintenance at every unit, fixed starting times and durations are determined. More than 75% of the maintenance work at the Bruno Leuschner Nuclear Power Plant is carried out by the plant's own maintenance personnel. Large-scale maintenance of every unit is controlled by a special project head. He is assisted by commissioners, each of whom is responsible for his own respective item. A daily control report is made. The organizational centre is a central office which works in shifts around the clock. All maintenance orders and reports of completion pass through this office; thus, the overall maintenance schedule can be corrected daily. To enforce the proposed operational strategy, suitable accompanying technical measures are required with respect to effective facility monitoring and technical diagnosis, purposeful improvement of particularly sensitive components and an increase in the effectiveness of maintenance work by special technologies and devices. (author)

  10. Survey on the FRP waste recycling system; FRP haikibutsu recycle system ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Using the area around the Ariake Sea in Kyushu as a model case, the FRP (fiber reinforced plastics) waste recycling system which can be established in Japan has been investigated in cooperation with local government bodies and fishery organizations. As a result, some proposals are provided. The recovery of waste boats utilizing existing sales outlets for fishing boats will facilitate efficient transport, efficient removal of vessel fixtures, and information management and user guidance via existing sales routes. This should make it possible to systematically secure and dispose a certain volume of scrapped FRP boats, and thus generate savings in the disposal costs. In the Phase 1, the main focus will be on establishing the recovery system for scrapped FRP boats to promote reuse and prevent improper disposal. In the Phase 2, the economics will be improved by expanding the recovery system to include other FRP waste products. In the Phase 3, the number of recyclable items will be increased, and thus the recycling system will be completed. 3 refs., 11 figs., 7 tabs.

  11. Management strategies for nuclear power plant outages

    International Nuclear Information System (INIS)

    More competitive energy markets have significant implications for nuclear power plant operations, including, among others, the need for more efficient use of resources and effective management of plant activities such as on-line maintenance and outages. Outage management is a key factor for safe, reliable and economic plant performance and involves many aspects: plant policy, coordination of available resources, nuclear safety, regulatory and technical requirements, and all activities and work hazards, before and during the outage. The IAEA has produced this report on nuclear power plant outage management strategies to provide both a summary and an update of a follow-up to a series of technical documents related to practices regarding outage management and cost effective maintenance. The aim of this publication is to identify good practices in outage management: outage planning and preparation, outage execution and post-outage review. As in in the related technical documents, this report aims to communicate these practices in such a way that they can be used by operating organizations and regulatory bodies in Member States. The report was prepared as part of an IAEA project on continuous process improvement. The objective of this project is to increase Member State capabilities in improving plant performance and competitiveness through the utilization of proven engineering and management practices developed and transferred by the IAEA

  12. Nuclear operations branch outage management strategy

    International Nuclear Information System (INIS)

    In 1991, partly in response to declining nuclear performance in Ontario Hydro, six priority areas were chosen where improvement efforts should be focused. Of these, outage management has the greatest potential for increasing near-term electrical generation. Many initiatives are being undertaken to improve performance in this key area. The outage management strategy is intended to focus these improvement efforts, and put outage management at Ontario Hydro's nuclear generating stations on a more predictable and business-like basis. This paper outlines the strategic planning process, and provides an overview of the outage management strategy. 2 refs, 1 tab., 4 figs

  13. EB-FRP 及 HB-FRP 加固预裂 RC梁对比试验研究%Experimental Analysis of Pre-cracked RC Beams Strengthened with EB-FRP and HB-FRP

    Institute of Scientific and Technical Information of China (English)

    管延华; 朱登元; 庄培芝; 李红超; 周志东

    2013-01-01

    On the basis of the crack characteristics of aging RC beam bridges ,the cross-section of RC simple beams with different pre-cracking levels were strengthened by the externally bonded FRP (EB-FRP)and the FRP-bolt hybrid bonding(HB-FRP)respectively to check the strengthening characteristics of HB-FRP .The flexural test with symmetrical loading on two points was conducted to study the mechanical behavior and failure mode of pre-crack beams strengthened with EB-FRP and HB-FRP .The influence of pre-cracking level on the FRP initial debonding load and FRP utilization ratio was assessed respectively .The test results show that the flexural capacity of pre-cracking beam strengthened with HB-FRP can be improved by 30% ~44% compared with the one with EB-FRP . The failure mode has been changed from FRP brittleness debonding of beam strengthened with EB-FRP to obvious ductility failure of beam strengthened with HB-FRP .Furthermore ,the crack distribution of RC beam has obvious influence on the FRP initial debonding load ,the FRP utilization ratio and the failure mode of strengthened pre-crack beams .%为验证FRP 螺栓加固新技术的合理性,结合现役钢筋混凝土桥梁带裂缝工作的特点,采用表面粘贴FRP(EB-FRP)加固技术和FRP 螺栓混合加固技术(HB-FRP),分别对不同预裂度的钢筋混凝土简支梁进行抗弯加固,通过两点对称加载抗弯试验研究加固预裂梁的受力特性和破坏模式,分析裂缝分布对加固预裂梁的剥离荷载及FRP材料利用率的影响。试验结果表明,与表面粘贴FRP加固技术相比较,采用 FRP 螺栓混合加固的预裂梁,抗弯极限承载能力提高30%~44%,加固后结构的破坏表现为明显的延性,改善了FRP脆性剥离破坏模式;另外,钢筋混凝土梁裂缝对FRP的剥离荷载、FRP材料的利用率及梁的破坏模式影响显著。

  14. Areva: experiences in outage services

    International Nuclear Information System (INIS)

    As the world leader in the nuclear industry, Areva is firmly committed to the safe and reliable operation of the Spanish nuclear power plants. Following this commitment, Areva has established the subsidiary Areva NP Services Spain as a local platform to provide nuclear services for the Spanish nuclear power plants. being integrated and supported by the global Areva Group, Areva NP Services Spain is able to offer services solutions to all customers demands while maintaining close and sustainable relationships with them. This integration also allows the Spanish personnel of Areva to employ their skills by working in multinational teams in international projects. This article will present the capacities, and the most important recent national and international project performed by Areva NP Services Spain in the field of outage services. (Author)

  15. Outage risk reduction at Diablo Canyon

    International Nuclear Information System (INIS)

    A formal risk reduction program was conducted at the Diablo Canyon Nuclear Generating plant as part of EPRI's Outage Risk Assessment and Management Program. The program began with a probabilistic and deterministic assessment of the frequency of core coolant boiling and core uncovery during shutdown operations. This step identified important contributors to risk, periods of high vulnerability, and potential mechanisms for reducing risk. Next, recovery strategies were evaluated and procedures, training, and outage schedules modified. Twelve risk reduction enhancements were developed and implemented. These enhancements and their impact are described in this paper. These enhancements reduced the calculated risk of core uncovery by about a factor of four for a refueling outage without lengthening the outage schedule; increased the outage efficiency, contributing to completing 11 days ahead of schedule; and helped to earn the highest achievable SALP rating from the NRC. (author)

  16. GUIDELINES FOR IMPLEMENTATION OF AN ADVANCED OUTAGE CONTROL CENTER TO IMPROVE OUTAGE COORDINATION, PROBLEM RESOLUTION, AND OUTAGE RISK MANAGEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Germain, Shawn St; Farris, Ronald; Whaley, April M; Medema, Heather; Gertman, David

    2014-09-01

    This research effort is a part of the Light-Water Reactor Sustainability (LWRS) Program, which is a research and development (R&D) program sponsored by Department of Energy (DOE) and performed in close collaboration with industry R&D programs that provide the technical foundations for licensing and managing the long-term, safe, and economical operation of current nuclear power plants. The LWRS program serves to help the U.S. nuclear industry adopt new technologies and engineering solutions that facilitate the continued safe operation of the plants and extension of the current operating licenses. Managing NPP outages is a complex and difficult task due to the large number of maintenance and repair activities that are accomplished in a short period of time. During an outage, the outage control center (OCC) is the temporary command center for outage managers and provides several critical functions for the successful execution of the outage schedule. Essentially, the OCC functions to facilitate information inflow, assist outage management in processing information, and to facilitate the dissemination of information to stakeholders. Currently, outage management activities primarily rely on telephone communication, face to face reports of status, and periodic briefings in the OCC. It is a difficult task to maintain current the information related to outage progress and discovered conditions. Several advanced communication and collaboration technologies have shown promise for facilitating the information flow into, across, and out of the OCC. The use of these technologies will allow information to be shared electronically, providing greater amounts of real-time information to the decision makers and allowing OCC coordinators to meet with supporting staff remotely. Passively monitoring status electronically through advances in the areas of mobile worker technologies, computer-based procedures, and automated work packages will reduce the current reliance on manually

  17. An Expert System in FRP Composite Material Design

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An expert system prototype for fibre-reinforced plastic matrix (FRP) composite material design,ESFRP, has been developed. The system consists of seven main functional parts: a general inference engine, a set of knowledge bases, a material properties algorithm base, an explanation engine, various data bases, several function models and the user interface. The ESFRP can simulate human experts to make design scheme for fibre-reinforced plastics design, FRP layered plates design and FRP typical engineering components design. It can also predict the material properties and make strength analysis according to the micro and macro mechanics of composite materials. A satisfied result can be gained through the reiterative design.

  18. Limit analysis on FRP-strengthened RC members

    Directory of Open Access Journals (Sweden)

    D. De Domenico

    2014-07-01

    Full Text Available Reinforced concrete (RC members strengthened with externally bonded fiber-reinforced-polymer (FRP plates are numerically investigated by a plasticity-based limit analysis approach. The key-concept of the present approach is to adopt proper constitutive models for concrete, steel reinforcement bars (re-bars and FRP strengthening plates according to a multi-yield-criteria formulation. This allows the prediction of concrete crushing, steel bars yielding and FRP rupture that may occur at the ultimate limit state. To simulate such limitstate of the analysed elements, two iterative methods performing linear elastic analyses with adaptive elastic parameters and finite elements (FEs description are employed. The peak loads and collapse mechanisms predicted for FRP-plated RC beams are validated by comparison with the corresponding experimental findings.

  19. Development of a nondestructive evaluation method for FRP bridge decks

    Science.gov (United States)

    Brown, Jeff; Fox, Terra

    2010-05-01

    Open steel grids are typically used on bridges to minimize the weight of the bridge deck and wearing surface. These grids, however, require frequent maintenance and exhibit other durability concerns related to fatigue cracking and corrosion. Bridge decks constructed from composite materials, such as a Fiber-reinforced Polymer (FRP), are strong and lightweight; they also offer improved rideability, reduced noise levels, less maintenance, and are relatively easy to install compared to steel grids. This research is aimed at developing an inspection protocol for FRP bridge decks using Infrared thermography. The finite element method was used to simulate the heat transfer process and determine optimal heating and data acquisition parameters that will be used to inspect FRP bridge decks in the field. It was demonstrated that thermal imaging could successfully identify features of the FRP bridge deck to depths of 1.7 cm using a phase analysis process.

  20. Durability of concrete structures strengthened with FRP laminates

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the fast freeze-thaw cycling test, the alkaline immersion test, the water immersion test and the wet-thermal exposure test, the influence of aggressive environments on mechanical behavior of FRP was studied. CFRP specimens subjected to aggressive environments showed good durability with no significant degradation in tensile strength and modulus; however, GFRP specimens exhibited a little decrease in mechanical property after aggressive environments exposure. Based on the fast freeze-thaw cycling test and the wet-thermal exposure test, the influence of aggressive environments on the bond behavior between FRP and concrete, mechanical behavior of concrete beams and columns strengthened with FRP laminates was studied. The results showed that the bond strength had a significant decrease compared with those specimens kept at room temperature, and the specimens strengthened with FRP exhibited good durability.

  1. Tensile tests of basalt FRP rebars using chemical anchorages

    OpenAIRE

    Neagoe, Catalin Andrei; Gil Espert, Lluís

    2013-01-01

    In the current report are analyzed the experimental results of initial tensile tests of Basalt FRP (BFRP) rebars provided by VSL. The investigation was conducted in the laboratory of CER LITEM. Objectives of the study: to determine the tensile strengths of 6 mm and 8 mm basalt FRP rebars, and to determine what type of test setup and anchorage system is best suited for future tensile tests of BFRP bars.

  2. Tensile tests of basalt FRP rebars using mechanical anchorages

    OpenAIRE

    Neagoe, Catalin Andrei; Gil Espert, Lluís

    2013-01-01

    In the current report are analyzed the experimental results of initial tensile tests of Basalt FRP (BFRP) rebars provided by VSL. The investigation was conducted on the 19th of February 2013, in the laboratory of CER LITEM. Objectives of the study: to determine the tensile strengths of 6 mm and 8 mm basalt FRP rebars, and to determine what type of test setup and anchorage system is best suited for future tensile tests of BFRP bars.

  3. Experimental bond behavior of FRP sheets glued on brick masonry

    OpenAIRE

    Oliveira, Daniel V.; Basílio, Ismael; Lourenço, Paulo B.

    2011-01-01

    This paper deals with the experimental characterization of the mechanical tensile and shear bond behavior of fiber reinforced polymer (FRP) sheets externally glued on masonry prisms, in terms of load capacity and stress distribution along the bonded length. The brick masonry adopted tries to replicate ancient brick masonry, by using handmade low strength solids bricks and low strength lime based mortar. Key parameters relative to the FRP-masonry interface response, particularly bo...

  4. Nonlinear Finite Element Analysis of FRP Strengthened Reinforced Concrete Beams

    Science.gov (United States)

    Sasmal, S.; Kalidoss, S.; Srinivas, V.

    2012-12-01

    This paper focuses on nonlinear analysis of parent and fiber reinforced polymer (FRP) strengthened reinforced concrete (RC) beam using general purpose finite element software, ANSYS. Further, it is aimed to investigate the suitability of different elements available in ANSYS library to represent FRP, epoxy and interface. 3-D structural RC solid element has been used to model concrete and truss element is employed for modeling the reinforcements. FRP has been modelled using 3-D membrane element and layered element with number of layers, epoxy is modelled using eight node brick element, and eight node layered solid shell is used to mathematically represent the concrete-FRP interface behavior. Initially, the validation of the numerical model for the efficacy of different elements (SOLID65 for concrete and LINK8 for reinforcement) and material models is carried out on the experimental beam reported in literature. The validated model, elements and material properties is used to evaluate the load-displacement and load-strain response behavior and crack patterns of the FRP strengthened RC beams. The numerical results indicated that significant improvement in the displacement in the strengthened RC beams with the advancement of cracks. The study shows that FRP with shell elements is recommended when single layer of FRP is used. When multi layered FRP is used, solid layered element can be a reasonably good choice whereas the epoxy matrix with linear solid element does not need further complicated model. Interfacial element makes the analysis minimally improved at the cost of complicated modeling issues and considerable computation time. Hence, for nonlinear analysis of usual strengthened structures, unless it is specifically required for, interface element may not be required and a full contact can be assumed at interface.

  5. San Onofre - the evolution of outage management

    International Nuclear Information System (INIS)

    With the addition of units 2 and 3 to San Onofre nuclear station in 1983 and 1984, it became evident that a separate group was needed to manage outages. Despite early establishment of a division to handle outages, it was a difficult journey to make the changes to achieve short outages. Early organizational emphasis was on developing an error-free operating environment and work culture. This is difficult for a relatively large organization at a three-unit site. The work processes and decision styles were designed to be very deliberate with many checks and balances. The organization leadership and accountability were focused in the traditional operations, maintenance, and engineering divisions. Later, our organization emphasis shifted to achieving engineering excellence. With a sound foundation of operating and engineering excellence, our organizational focus has turned to achieving quality outages. This means accomplishing the right work in a shorter duration and having the units run until the next refueling

  6. Finite element analysis of FRP-strengthened RC beams

    Directory of Open Access Journals (Sweden)

    Teeraphot Supaviriyakit

    2004-05-01

    Full Text Available This paper presents a non-linear finite element analysis of reinforced concrete beam strengthened with externally bonded FRP plates. The finite element modeling of FRP-strengthened beams is demonstrated. Concrete and reinforcing bars are modeled together as 8-node isoparametric 2D RC element. The FRP plate is modeled as 8-node isoparametric 2D elastic element. The glue is modeled as perfect compatibility by directly connecting the nodes of FRP with those of concrete since there is no failure at the glue layer. The key to the analysis is the correct material models of concrete, steel and FRP. Cracks and steel bars are modeled as smeared over the entire element. Stress-strain properties of cracked concrete consist of tensile stress model normal to crack, compressive stress model parallel to crack and shear stress model tangential to crack. Stressstrain property of reinforcement is assumed to be elastic-hardening to account for the bond between concrete and steel bars. FRP is modeled as elastic-brittle material. From the analysis, it is found that FEM can predict the load-displacement relation, ultimate load and failure mode of the beam correctly. It can also capture the cracking process for both shear-flexural peeling and end peeling modes similar to the experiment.

  7. Power Outage, Business Continuity and Businesses' Choices of Power Outage Mitigation Measures

    Directory of Open Access Journals (Sweden)

    Ali Asgary

    2011-01-01

    Full Text Available Problem statement: Power outage has been mentioned as one of the most experienced and perceived risks by various types of businesses and organizations. Thus, reducing the impacts of power outage has become a key agenda in business continuity planning. Back-up or stand-by generators are among the most well known measures taken by power consumers to tackle the power outage problem. Approach: A survey was conducted to understand various aspects of power outage and the impacts of power outrage on businesses. In addition a choice experiment method was used to derive businesses’ preferences for different power outage mitigation measures that would have a range of prices, space requirements, air and noise pollution as well as mobility attributes using a sample of Canadian businesses located in the . Sample was drawn from businesses operating in the Greater Toronto Area (GTA and surrounding communities in Ontario, Canada. Results: It was found that majority of businesses have experienced and unconvinced by power outage and consider it to be a major risk to their operations. Production loss, data loss, damage to equipment and loss of lighting are the most significant sources for inconveniences caused by the power outages. It was found that a considerable number of businesses have not taken appropriate measures to mitigate this risk. Estimations from the responses revealed that sample businesses had a positive willingness to pay for power outage reduction and that businesses prefer power outage mitigation measures that are least costly, have low levels of air and noise pollution and occupy smaller spaces respectively. Conclusion: An uninterrupted power supply is an important element of business continuity in today’s business world. Although many businesses are not fully prepared against power outages, they are willing to pay for low cost and low pollution power outage mitigation measures.

  8. Secreted Frizzled-Related Protein 2 (sFRP2) Functions as a Melanogenic Stimulator; the Role of sFRP2 in UV-Induced Hyperpigmentary Disorders.

    Science.gov (United States)

    Kim, Misun; Han, Jae Ho; Kim, Jang-Hee; Park, Tae Jun; Kang, Hee Young

    2016-01-01

    In this study, we found that secreted frizzled-related protein 2 (sFRP2) is overexpressed in the hyperpigmentary skin of melasma and solar lentigo and in acutely UV-irradiated skin. To investigate the effect of sFRP2 on melanogenesis, normal human melanocytes were infected with sFRP2-lentivirus or sh-sFRP2. It was found that sFRP2 stimulates melanogenesis through microphthalmia-associated transcription factor and/or tyrosinase upregulation via β-catenin signaling. The stimulatory action of sFRP2 in pigmentation was further confirmed in melanocytes cocultured with fibroblasts and in ex vivo cultured skin. The findings suggest that sFRP2 functions as a melanogenic stimulator and that it plays a role in the development of UV-induced hyperpigmentary disorders. PMID:26763443

  9. Estimating the spatial distribution of power outages during hurricanes in the Gulf coast region

    International Nuclear Information System (INIS)

    Hurricanes have caused severe damage to the electric power system throughout the Gulf coast region of the US, and electric power is critical to post-hurricane disaster response as well as to long-term recovery for impacted areas. Managing power outage risk and preparing for post-storm recovery efforts requires accurate methods for estimating the number and location of power outages. This paper builds on past work on statistical power outage estimation models to develop, test, and demonstrate a statistical power outage risk estimation model for the Gulf Coast region of the US. Previous work used binary hurricane-indicator variables representing particular hurricanes in order to achieve a good fit to the past data. To use these models for predicting power outages during future hurricanes, one must implicitly assume that an approaching hurricane is similar to the average of the past hurricanes. The model developed in this paper replaces these indicator variables with physically measurable variables, enabling future predictions to be based on only well-understood characteristics of hurricanes. The models were developed using data about power outages during nine hurricanes in three states served by a large, investor-owned utility company in the Gulf Coast region

  10. Outages 1999 and 2000, investments in safety and long-term operation of NE Krsko

    International Nuclear Information System (INIS)

    Plant outage is an important part of nuclear power plant operation. During that time the conditions are established for the performance of specific activities, such as refueling, tests, inspections, preventive and corrective maintenance and modifications, that are intended to confirm proper condition and availability of safety and other important components and improve overall plant safety and reliability. It is well know that in Nuclear Power Plant Krsko (Nuklearna elektrarna Krsko NEK) during Outage 2000 new Steam Generators (SGs) will be placed in service, while Outage '99 was used for preparatory works. But the importance of those two outages is even greater, because they are implementing a broad number of improvements and establishing a basis for long-term plant operation. Outage '99 required very detailed planning to assure a good control over the outage activities and operational plant systems necessary for safe shutdown. Numerous activities took place in a relatively narrow space in the Reactor Building. Some of these activities will have a big significance for the future. The article treats the status update and summarizes the specifics and importance of the mentioned activities to long-term plant safe and reliable operation.(author)

  11. Major outages at nuclear power stations: outage strategy and its implementation

    International Nuclear Information System (INIS)

    In the new era of competition in the recently privatised electricity generating market, the costs of electric power production can be brought down by reducing plant outages to the lowest levels compatible with safety constraints. Some of the management principles used to achieve such low duration outages are described. High plant reliability following the station's return to power must also be ensured. (UK)

  12. Maintenance and Outage Management Assessment (MOMA)

    International Nuclear Information System (INIS)

    The competitive environment has significant implications for nuclear power plant (NPP) operations, which include, inter alia, the need for efficient use of resources and effective management of plant activities of maintenance and outages. The purpose of NPP maintenance and outages is to allow NPPs to use all those functions necessary for safe and reliable power production by keeping them available and adequate maintenance programme is essential. The maintenance programme covers all preventive and remedial measures, both administrative and technical, necessary to identify and mitigate degradation of a functioning system, structure or component, or restore the design functions of a failed system, structure or component to an acceptable level. In response to the needs of MSs, NPES (Nuclear Power Section, Division of Nuclear Power, IAEA) plans to strengthen its services. NPES services will not only continue to provide its 'traditional' products of publications of nuclear industrial best practices and technical implementation of TC projects on plant maintenance and outage management, but also be expanded to deliver, in a timely manner, technical support missions as requested by MSs for NPPs. One of many services is Maintenance and Outage Management Assessment (MOMA). The NPP can obtain support and assistance in assessment and optimisation of its maintenance program and/or outage management. It aims to help the NPP improve its performance of maintenance and outage in a competitive nuclear power business environment. The specific benefits of the assessment are as follows: a) disseminate nuclear industrial best practices on maintenance program and outage management in the world, b) benchmark, evaluate and optimise the approach of maintenance program and outage management and c) identify solutions to known problems at nuclear power plants, if any. MOMA is conducted at the request of NPPs of any IAEA Member States. MOMA consists in a technical mission/visit for 1-3 weeks by

  13. Facility Response Plan (FRP) Sites in Region 6, 5/2011

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes locations of sites noted as having a Facility Response Plan (FRP). Having an FRP demonstrates a facility's preparedness to respond to a worst...

  14. Contingency Analysis of Cascading Line Outage Events

    Energy Technology Data Exchange (ETDEWEB)

    Thomas L Baldwin; Magdy S Tawfik; Miles McQueen

    2011-03-01

    As the US power systems continue to increase in size and complexity, including the growth of smart grids, larger blackouts due to cascading outages become more likely. Grid congestion is often associated with a cascading collapse leading to a major blackout. Such a collapse is characterized by a self-sustaining sequence of line outages followed by a topology breakup of the network. This paper addresses the implementation and testing of a process for N-k contingency analysis and sequential cascading outage simulation in order to identify potential cascading modes. A modeling approach described in this paper offers a unique capability to identify initiating events that may lead to cascading outages. It predicts the development of cascading events by identifying and visualizing potential cascading tiers. The proposed approach was implemented using a 328-bus simplified SERC power system network. The results of the study indicate that initiating events and possible cascading chains may be identified, ranked and visualized. This approach may be used to improve the reliability of a transmission grid and reduce its vulnerability to cascading outages.

  15. Concrete-Filled-Large Deformable FRP Tubular Columns under Axial Compressive Loading

    OpenAIRE

    Omar I. Abdelkarim; Mohamed A. ElGawady

    2015-01-01

    The behavior of concrete-filled fiber tubes (CFFT) polymers under axial compressive loading was investigated. Unlike the traditional fiber reinforced polymers (FRP) such as carbon, glass, aramid, etc., the FRP tubes in this study were designed using large rupture strains FRP which are made of recycled materials such as plastic bottles; hence, large rupture strain (LRS) FRP composites are environmentally friendly and can be used in the context of green construction. This study performed finite...

  16. FRP Composites Strengthening of Concrete Columns under Various Loading Conditions

    Directory of Open Access Journals (Sweden)

    Azadeh Parvin

    2014-04-01

    Full Text Available This paper provides a review of some of the progress in the area of fiber reinforced polymers (FRP-strengthening of columns for several loading scenarios including impact load. The addition of FRP materials to upgrade deficiencies or to strengthen structural components can save lives by preventing collapse, reduce the damage to infrastructure, and the need for their costly replacement. The retrofit with FRP materials with desirable properties provides an excellent replacement for traditional materials, such as steel jacket, to strengthen the reinforced concrete structural members. Existing studies have shown that the use of FRP materials restore or improve the column original design strength for possible axial, shear, or flexure and in some cases allow the structure to carry more load than it was designed for. The paper further concludes that there is a need for additional research for the columns under impact loading senarios. The compiled information prepares the ground work for further evaluation of FRP-strengthening of columns that are deficient in design or are in serious need for repair due to additional load or deterioration.

  17. Outage management and health physics issue, 2007

    International Nuclear Information System (INIS)

    The focus of the May-June issue is on outage management and health physics. Major articles/reports in this issue include: India: a potential commercial opportunity, a U.S. Department of Commerce Report, by Joe Neuhoff and Justin Rathke; The changing climate for nuclear energy, by Skip Bowman, Nuclear Energy Insitute; Selecting protective clothing, by J. Mark Price, Southern California Edison; and Succssful refurbishment outage, by Sudesh K. Gambhir, Omaha Public Power District. Industry innovation articles in this issue are: Containment radiation monitoring spiking, by Michael W. Lantz and Robert Routolo, Arizona Public Service Company; Improved outage performance, by Michael Powell and Troy Wilfong, Arizona Public Service Company, Palo Verde Nuclear Generating Station; Stop repacking valves and achieve leak-free performance, by Kenneth Hart, PPL Susquehanna LLC; and Head assembly upgrade package, by Timothy Petit, Dominion Nuclear

  18. Concrete-Filled-Large Deformable FRP Tubular Columns under Axial Compressive Loading

    Directory of Open Access Journals (Sweden)

    Omar I. Abdelkarim

    2015-10-01

    Full Text Available The behavior of concrete-filled fiber tubes (CFFT polymers under axial compressive loading was investigated. Unlike the traditional fiber reinforced polymers (FRP such as carbon, glass, aramid, etc., the FRP tubes in this study were designed using large rupture strains FRP which are made of recycled materials such as plastic bottles; hence, large rupture strain (LRS FRP composites are environmentally friendly and can be used in the context of green construction. This study performed finite element (FE analysis using LS-DYNA software to conduct an extensive parametric study on CFFT. The effects of the FRP confinement ratio, the unconfined concrete compressive strength ( , column size, and column aspect ratio on the behavior of the CFFT under axial compressive loading were investigated during this study. A comparison between the behavior of the CFFTs with LRS-FRP and those with traditional FRP (carbon and glass with a high range of confinement ratios was conducted as well. A new hybrid FRP system combined with traditional and LRS-FRP is proposed. Generally, the CFFTs with LRS-FRP showed remarkable behavior under axial loading in strength and ultimate strain. Equations to estimate the concrete dilation parameter and dilation angle of the CFFTs with LRS-FRP tubes and hybrid FRP tubes are suggested.

  19. Benchmark Report on Key Outage Attributes: An Analysis of Outage Improvement Opportunities and Priorities

    Energy Technology Data Exchange (ETDEWEB)

    Germain, Shawn St. [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Farris, Ronald [Idaho National Laboratory (INL), Idaho Falls, ID (United States)

    2014-09-01

    Advanced Outage Control Center (AOCC), is a multi-year pilot project targeted at Nuclear Power Plant (NPP) outage improvement. The purpose of this pilot project is to improve management of NPP outages through the development of an AOCC that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. This report documents the results of a benchmarking effort to evaluate the transferability of technologies demonstrated at Idaho National Laboratory and the primary pilot project partner, Palo Verde Nuclear Generating Station. The initial assumption for this pilot project was that NPPs generally do not take advantage of advanced technology to support outage management activities. Several researchers involved in this pilot project have commercial NPP experience and believed that very little technology has been applied towards outage communication and collaboration. To verify that the technology options researched and demonstrated through this pilot project would in fact have broad application for the US commercial nuclear fleet, and to look for additional outage management best practices, LWRS program researchers visited several additional nuclear facilities.

  20. A mechanical model for FRP-strengthened beams in bending

    Directory of Open Access Journals (Sweden)

    P. S. Valvo

    2012-10-01

    Full Text Available We analyse the problem of a simply supported beam, strengthened with a fibre-reinforced polymer (FRP strip bonded to its intrados and subjected to bending couples applied to its end sections. A mechanical model is proposed, whereby the beam and FRP strip are modelled according to classical beam theory, while the adhesive and its neighbouring layers are modelled as an interface having a piecewise linear constitutive law defined over three intervals (elastic response – softening response – debonding. The model is described by a set of differential equations with appropriate boundary conditions. An analytical solution to the problem is determined, including explicit expressions for the internal forces, displacements and interfacial stresses. The model predicts an overall non-linear mechanical response for the strengthened beam, ranging over several stages: from linearly elastic behaviour to damage, until the complete detachment of the FRP reinforcement.

  1. Residential outage cost estimation: Hong Kong

    International Nuclear Information System (INIS)

    Hong Kong has almost perfect electricity reliability, the result of substantial investments ultimately financed by electricity consumers who may be willing to accept lower reliability in exchange for lower bills. But consumers with high outage costs are likely to reject the reliability reduction. Our ordered-logit regression analysis of the responses by 1876 households to a telephone survey conducted in June 2013 indicates that Hong Kong residents exhibit a statistically-significant preference for their existing service reliability and rate. Moreover, the average residential cost estimate for a 1-h outage is US$45 (HK$350), topping the estimates reported in 10 of the 11 studies published in the last 10 years. The policy implication is that absent additional compelling evidence, Hong Kong should not reduce its service reliability. - Highlights: • Use a contingent valuation survey to obtain residential preferences for reliability. • Use an ordered logit analysis to estimate Hong Kong's residential outage costs. • Find high outage cost estimates that imply high reliability requirements. • Conclude that sans new evidence, Hong Kong should not reduce its reliability

  2. Pricing power outages in the Netherlands

    Energy Technology Data Exchange (ETDEWEB)

    Baarsma, Barbara E.; Hop, J. Peter [SEO Economic Research/University of Amsterdam, Amsterdam (Netherlands)

    2009-09-15

    In most Western countries, the power grid provides electricity more than 99% of the time. To maintain reliability at such high levels, energy companies have to continually invest in electric transmission- and distribution systems. Since customers of electricity cannot switch from one distribution network to another, no economic incentive exists that matches the supplied reliability to customer preferences. Either under- or over-investment in reliability may thus result. In order to introduce market-like incentives, the Dutch Energy Regulator introduced a regulatory system based on the (perceived) costs of power outages. An essential ingredient of the regulation is the cost of a power outage of a particular duration (i.e., 1 minute). This paper measures these outage cost by using conjoint analysis. We find that the social cost of the present Dutch level of reliability - that is, one outage of two hours every four years - is EUR2.80 on average for every household, and EUR33.10 on average for every SME firm. The total costs to Dutch society are almost EUR50 million. (author)

  3. Analysis and behaviour of FRP-confined short concrete columns subjected to eccentric loading

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Fibre-reinforced polymer (FRP) composites were widely utilized in civil engineering structures as the retrofit of reinforced concrete (RC) columns. To design FRP jackets safely and economically, the behaviour of such columns should be predicted first. This paper is concerned with the analysis and behaviour of FRP-confined RC circular and rectangular short columns subjected to eccentric loading. A simple design-oriented stress-strain model for FRP-confined concrete in a section analysis was first proposed. The accuracy was then proved by two test data. Following that, a parametric study including amount of FRP confinement, FRP strain capacity, unconfined concrete strength and shape of column section is provided. Some conclusions were obtained at the end of the paper. The work here will provide a comprehensive understanding of the behaviour of FRP-confined concrete columns. The simplicity of the model also enables a simple equivalent stress block to be developed for direct use in practical design.

  4. Qinshan CANDU NPP outage performance improvement through benchmarking

    International Nuclear Information System (INIS)

    With the increasingly fierce competition in the deregulated Energy Market, the optimization of outage duration has become one of the focal points for the Nuclear Power Plant owners around the world. People are seeking various ways to shorten the outage duration of NPP. Great efforts have been made in the Light Water Reactor (LWR) family with the concept of benchmarking and evaluation, which great reduced the outage duration and improved outage performance. The average capacity factor of LWRs has been greatly improved over the last three decades, which now is close to 90%. CANDU (Pressurized Heavy Water Reactor) stations, with its unique feature of on power refueling, of nuclear fuel remaining in the reactor all through the planned outage, have given raise to more stringent safety requirements during planned outage. In addition, the above feature gives more variations to the critical path of planned outage in different station. In order to benchmarking again the best practices in the CANDU stations, Third Qinshan Nuclear Power Company (TQNPC) have initiated the benchmarking program among the CANDU stations aiming to standardize the outage maintenance windows and optimize the outage duration. The initial benchmarking has resulted the optimization of outage duration in Qinshan CANDU NPP and the formulation of its first long-term outage plan. This paper describes the benchmarking works that have been proven to be useful for optimizing outage duration in Qinshan CANDU NPP, and the vision of further optimize the duration with joint effort from the CANDU community. (authors)

  5. Mechanical anchorage of FRP tendons – A literature review

    DEFF Research Database (Denmark)

    Schmidt, Jacob W.; Bennitz, Anders; Täljsten, Björn;

    2012-01-01

    High tensile strength, good resistance to degradation and creep, low weight and, to some extent, the ability to change the modulus of elasticity are some of the advantages of using prestressed, unidirectional FRP (Fibre Reinforced Polymer) tendon systems. Bonded and non-bonded versions of these s...

  6. Evaluation of FRP Bars Performance under High Temperature

    Science.gov (United States)

    Kashwani, Ghanim A.; Al-Tamimi, Adil K.

    Fiber reinforced polymer bars are increasingly used in the construction industry. Strength, durability and stability are the main criteria for selection and design of FRP. However in case of exposure to high temperature, the change in the material properties affects the overall structure performance. Extensive materials evaluation and numerical modeling are needed to determine any repair/demolish recommendations. FRP bar is one of the main choices for high corrosion resistance in sever environmental conditions. However, FRP materials lose their strength and stiffness at early stage due to high temperature. Many investigations have been carried out on the performance of FRP bond strength exposed to high temperature. In this paper, two different groups of Glass fiber reinforced polymer (GFRP) specimens were tested to determine the effect of the high temperature. Tensile test was applied on all specimens with three different speed rates where the critical temperature for this experiment was 350 °C. From the results and the graphs, the effects of the temperature were explained and analyzed. It showed a reduction of 32% in the tensile strength due to high temperature exposure and an increase in its ductility.

  7. Nuclear cost control focuses on refueling outages

    International Nuclear Information System (INIS)

    Extending operating cycles and shortening refueling outages are the mainstays of utility efforts to improve the economics of nuclear generation. Here are key management approaches that have contributed to recent successes. Improving operating efficiency remains the byword of nuclear power producers, as they intensify their drive to reduce operation and maintenance (O and M) costs and survive--even thrive--in a competitive environment. Because replacement-power and other costs can incur penalties of $0.5-million or more for each that a nuclear unit is inoperative--and almost $3-million/day, for one utility--refueling outages are an obvious focal point for such efforts, By the same token, the impact on the bottom line is greater and more dramatic here than for other cost-saving activities

  8. Outage management and health physics issue, 2006

    International Nuclear Information System (INIS)

    The focus of the May-June issue is on outage management and health physics. Major articles/reports in this issue include: A design with experience for the U.S., by Michael J. Wallace, Constellation Generation Group; Hope to be among the first, by Randy Hutchinson, Entergy Nuclear; Plans to file COLs in 2008, by Garry Miller, Progress Energy; Evolution of ICRP's recommendations, by Lars-Erik Holm, ICRP; European network on education and training in radiological protection, by Michele Coeck, SCK-CEN, Belgium; Outage managment: an important tool for improving nuclear power plant performance, by Thomas Mazour and Jiri Mandula, IAEA, Austria; and Plant profile: Exploring new paths to excellence, by Anne Thomas, Exelon Nuclear

  9. Record outage at South Texas Project

    International Nuclear Information System (INIS)

    The outage at South Texas Project's nuclear power plant Unit 2 was completed in 17 days, 14 hours and 10 minutes. Westinghouse was responsible for three critical path activities. Steam generator maintenance and repair including plug inspections and contingency repairs; 100 percent eddy current testing; tube plugging and stabilisation; in-situ tube pressure testing; sludge lancing of the secondary side; and removal and installation of manway covers and nozzle dams. Refueling services included reactor disassembly and reassembly, refueling and dynamic rod worth measurement. Turbine generator inspection included substantial improvements to the end turn bracing system, two feed-pump turbine inspections, extensive main turbine valve change-outs, MSR inspections, lube oil cooler inspection and EH system flush. This paper details the steam generator and refueling portions of the outage program performed by Westinghouse Nuclear Services and the critical preplanning and communications activities coordinated by HLP. (author)

  10. Advanced Outage and Control Center: Strategies for Nuclear Plant Outage Work Status Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Weatherby

    2012-05-01

    The research effort is a part of the Light Water Reactor Sustainability (LWRS) Program. LWRS is a research and development program sponsored by the Department of Energy, performed in close collaboration with industry to provide the technical foundations for licensing and managing the long-term, safe and economical operation of current nuclear power plants. The LWRS Program serves to help the US nuclear industry adopt new technologies and engineering solutions that facilitate the continued safe operation of the plants and extension of the current operating licenses. The Outage Control Center (OCC) Pilot Project was directed at carrying out the applied research for development and pilot of technology designed to enhance safe outage and maintenance operations, improve human performance and reliability, increase overall operational efficiency, and improve plant status control. Plant outage management is a high priority concern for the nuclear industry from cost and safety perspectives. Unfortunately, many of the underlying technologies supporting outage control are the same as those used in the 1980’s. They depend heavily upon large teams of staff, multiple work and coordination locations, and manual administrative actions that require large amounts of paper. Previous work in human reliability analysis suggests that many repetitive tasks, including paper work tasks, may have a failure rate of 1.0E-3 or higher (Gertman, 1996). With between 10,000 and 45,000 subtasks being performed during an outage (Gomes, 1996), the opportunity for human error of some consequence is a realistic concern. Although a number of factors exist that can make these errors recoverable, reducing and effectively coordinating the sheer number of tasks to be performed, particularly those that are error prone, has the potential to enhance outage efficiency and safety. Additionally, outage management requires precise coordination of work groups that do not always share similar objectives. Outage

  11. How individual traces and interactive timelines could support outage execution - Toward an outage historian concept

    International Nuclear Information System (INIS)

    In the context of a project that is designing innovative ICT-based solutions for the organizational concept of outage management, we focus on the informational process of the OCR (Outage Control Room) underlying the execution of the outages. Informational process are based on structured and unstructured documents that have a key role in the collaborative processes and management of the outage. We especially track the structured and unstructured documents, electronically or not, from creation to sharing. Our analysis allows us to consider that the individual traces produced by an individual participant with a specific role could be multi-purpose and support sharing between participants without creating duplication of work. The ultimate goal is to be able to generate an outage historian, that is not just focused on highly structured information, which could be useful to improve the continuity of information between participants. We study the implementation of this approach through web technologies and social media tools to address this issue. We also investigate the issue of data access through interactive visualization timelines coupled with other modality's to assist users in the navigation and exploration of the proposed historian. (authors)

  12. Finnish outage management practices to reduce occupational doses and shorten outage duration

    International Nuclear Information System (INIS)

    Two Finnish nuclear power stations, TVO and Loviisa, have been among the world leaders in nuclear power plants. The plants consistently accomplish refueling outages in less than 25 days and outage occupational doses below 50 person-rem per unit. As U.S. utilities enter a deregulated market, cost reduction has become a paramount interest along with safe nuclear plant operations. U.S. attention has focused on European plant experience to better understand the relationship between shorter refueling outages and reduction in occupational dose. This paper summarizes the observations made during a NARTC site visit in October, 1995, to TVO and Loviisa to study health physics management practices to achieve this world class performance. Planning and selection of work is critical to the success of a shorter outage. Planning needs to occur by outage time, in-plant zone and be resource loaded/coordinated. The TVO plant works to a 10-y planning matrix. Only required work is approved at Loviisa; nice to do work is not allowed. Training of Finnish workers occurs in a carefully laid out plan from apprenticeship to journeyman levels. Finnish attitudes about radiation protection and work performance is discussed as also being a key to Finnish successes

  13. Indicators for management of planned outages in nuclear power plants

    International Nuclear Information System (INIS)

    The outages considered within the scope of this publication are planned refuelling outages (PWR and BWR nuclear power plants) and planned outages associated with major maintenance, tests and inspections (PHWR and LWGR nuclear power plants). The IAEA has published some valuable reports providing guidance and assistance to operating organizations on outage management. This TECDOC outlines main issues to be considered in outage performance monitoring and provides guidance to operating organizations for the development and implementation of outage programmes which could enhance plant safety, reliability and economics. It also complements the series of reports published by the IAEA on outage management and on previous work related to performance indicators developed for monitoring different areas of plant operation, such as safety, production, reliability and economics. This publication is based upon the information presented at a technical meeting to develop a standardized set of outage indicators for outage optimization, which was organised in Vienna, 6-9 October 2003. At this meeting, case studies and good practices relating to performance indicator utilization in the process of planned outage management were presented and discussed

  14. Behavior of FRP-Confined Concrete-Filled Steel Tube Columns

    OpenAIRE

    Yiyan Lu; Na Li; Shan Li

    2014-01-01

    This paper presents the results of an experimental study into the behavior of concrete-filled steel tube columns confined by fiber-reinforced polymer (FRP). Eleven columns were tested to investigate the effects of the FRP layer number, the thickness of the steel tube and concrete strength on their load capacity and axial deformation capacity. The experimental results indicated that the FRP wrap can effectively confine the concrete expansion and delay the local buckling of the steel tube. Both...

  15. Numerical Study of FRP Reinforced Concrete Slabs at Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Masoud Adelzadeh

    2014-02-01

    Full Text Available One-way glass fibre reinforced polymer (GFRP reinforced concrete slabs at elevated temperatures are investigated through numerical modeling. Serviceability and strength requirements of ACI-440.1R are considered for the design of the slabs. Diagrams to determine fire endurance of slabs by employing “strength domain” failure criterion are presented. Comparisons between the existing “temperature domain” method with the more representative “strength domain” method show that the “temperature domain” method is conservative. Additionally, a method to increase the fire endurance of slabs by placing FRP reinforcement in two layers is investigated numerically. The amount of fire endurance gained by placing FRP in two layers increases as the thickness of slab increases.

  16. Inventory of FRP strengthening methods in masonry structures

    OpenAIRE

    Islam, Rashadul

    2008-01-01

    Masonry structures are prone to extensive damage followed by failure and collapse when subjected to loads resulting from wind, earthquake and other natural or man-made events. Recent earthquakes and terrorist acts have clearly demonstrated that the development of effective and affordable strategies for the strengthening of masonry is urgently needed. As a response to these challenges, fiber-reinforced polymer (FRP) composites may offer technically and economically viable soluti...

  17. Assessment of Infrared Thermography for NDE of FRP Bridge Decks

    OpenAIRE

    Miceli, Marybeth

    2000-01-01

    Statistics released in the fall 1989 showed that 238,357 (41%) of the nation's 577,710 bridges are either structurally deficient or functionally obsolete. New materials, such as fiber reinforced polymeric composites (FRP), are being suggested for use in bridge systems to solve some of the current problems. These materials are thought to be less affected by corrosive environmental conditions than conventional civil engineering materials. Therefore they may require less maintenance and provi...

  18. Bingham Pump Outage Pits: Environmental information document

    International Nuclear Information System (INIS)

    Seven waste sites known as the Bingham Pump Outage Pits located in areas of the Savannah River Plant (SRP) received solid waste containing an estimated 4 Ci of low-level radioactivity in 1957-1958. These sites were subsequently backfilled and have been inactive since that time. Most of the radioactivity at the Bingham Pump Outage Pits has been eliminated by radioactive decay. A total of approximately 1 Ci of activity (primarily 137Cs and 90Sr) is estimated to remain at the seven sites. The closure options considered for the Bingham Pump Outage Pits are waste removal and closure, no waste removal and closure, and no action. The predominant pathways for human exposure to chemical and/or radioactive constituents are through surface, subsurface, and atmospheric transport. Modeling calculations were made to determine the risks to human population via these general pathways for the three postulated closure options. An ecological assessment was conducted to predict the environmental impacts on aquatic and terrestrial biota. The relative costs for each of the closure options were estimated. Evaluation indicates that the relative human health risks for all closure options are small. The greatest public risk would occur after the waste site was released to unrestricted public use (assumed to occur in Year 2085) via the groundwater pathway to a well. The cost estimates show that the waste removal and closure option is the most expensive (89.6 million dollars). The cost of the no waste removal and the no action options is $800,000. 35 refs., 26 figs., 47 tabs

  19. Mast sipping and MULTIINSPECTION shorten refueling outages

    International Nuclear Information System (INIS)

    Innovative inspection systems from Siemens can significantly contribute towards shortening the time needed for refuelling outages. Mast sipping is a technique which provides fast information on the condition of fuel assemblies scheduled for further use in the reactor core. The system MULTIINSPECTION allows standard inspections of fuel assemblies and other core components to be performed without having to use the refuelling machine all of the time. In addition to these benefits, the new procedures considerably reduce the radiation exposure of operating personnel. These new procedures and the associated equipment can be adapted to power plant operations and equipment to more effectively perform required service activities. (UK)

  20. Glass FRP reinforcement in rehabilitation of concrete marine infrastructure

    International Nuclear Information System (INIS)

    Fiber reinforced polymer (FRP) reinforcements for concrete structures are gaining wide acceptance as a suitable alternative to steel reinforcements. The primary advantage is that they do not suffer corrosion and hence they promise to be more durable in environments where steel reinforced concrete has a limited life span. Concrete wharves and jetties are examples of structures subjected to such harsh environments and represent the general class of marine infrastructure in which glass FRP (GFRP) reinforcement should be used for improved durability and service life. General design considerations which make glass FRP suitable for use in marine concrete rehabilitation projects are discussed. A case study of recent wharf rehabilitation project in Canada is used to reinforce these considerations. The structure consisted of a GFRP reinforced concrete deck panel and steel - GFRP hybrid reinforced concrete pile cap. A design methodology is developed for the hybrid reinforcement design and verified through testing. The results of a field monitoring program are used to establish the satisfactory field performance of the GFRP reinforcement. The design concepts presented in the paper are applicable to many concrete marine components and other structures where steel reinforcement corrosion is a problem. (author)

  1. The cost of power outages on Taiwan's industry

    International Nuclear Information System (INIS)

    Information on the costs incurred by electricity customers as a result of power interruptions (total outages) or power curtailments (partial outages) is important for planning the desired capacity level of electricity systems, the efficient and equitable setting of electricity prices and the development of priority service programs. Therefore, evaluation of outage costs is an important issue for many power companies and energy researchers. The purpose of this study is first to distinguish between the various types of power outages and their characteristics. Second, to evaluate the cost of power outages due to shortages in generation capacity in Taiwan. And finally, to determine the implications and limitations imposed by the outage costs in terms of both economics and their role in the decision making process

  2. Effective communication - The key to satisfying outage material requirements

    International Nuclear Information System (INIS)

    Satisfying outage material requirements for a nuclear station can be a frustrating challenge. Utility inventories have been developed based primarily on preventive and corrective maintenance requirements rather than outage maintenance and modification material requirements. Since a significant volume of material procurements is necessary to satisfy outage material requirements, it is crucial to effectively communicate these needs when planning outage activities. At Public Service Electric and Gas (PSE and G) Corporation portions of the management information system (MIS) has been utilized to order, expedite, track and communicate the status of station outage material needs. This communication tool is called the material coordination system (MCS). The MCS has improved success at meeting both routine and crucial outage commitments by having material available when it is needed in the schedule

  3. PMU Placement for Line Outage Identification via Multiclass Logistic Regression

    OpenAIRE

    Kim, Taedong; Wright, Stephen J

    2014-01-01

    We consider the problem of identifying a single line outage in a power grid by using data from phasor measurement units (PMUs). When a line outage occurs, the voltage phasor of each bus node changes in response to the change in network topology. Each individual line outage has a consistent "signature," and a multiclass logistic regression (MLR) classifier can be trained to distinguish between these signatures reliably. We consider first the ideal case in which PMUs are attached to every bus, ...

  4. Outage analysis of blind cooperative diversity

    KAUST Repository

    Tourki, Kamel

    2011-06-06

    Mobile users with single antennas can still take advantage of spatial diversity through cooperative space-time-encoded transmission. In this paper, we considered a scheme in which a relay chooses to cooperate only if its source-relay channel is of an acceptable quality, and we evaluate the usefulness of relaying when the source acts blindly and ignores the decision of the relays whether they may cooperate or not. In our study, we consider the regenerative relays in which the decisions to cooperate are based on a targeted end-to-end data rate R. We derived the end-to-end outage probability for a transmission rate R and a code rate ρ and look at a power allocation strategy between the source and the relays in order to minimize the end-to-end outage probability at the destination for high signal-to-noise ratio, by using the golden section search method. Performance results show that the computer simulations-based results coincide with our analytical results. Copyright © 2011 John Wiley & Sons, Ltd.

  5. Analysis of beam pumping system utilizing FRP sucker rod. FRP sakka roddo ni yoru ponpingu no kyodo kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Yasuo; Kurimura, Hideki (Teikoku Oil Co., Ltd., Tokyo (Japan))

    1989-11-01

    The performance of the FRP sucker rod pumping system in an oil field was analyzed. The analyses were carried out using programs of which diagrams of load and displacement at the pump location are determined from surface data by use of a dynamometer. The production rate of the FRP system fluctuates on a larger scale than the steel sucker rod pumping system even in a same condition, sometimes the production rate becomes nearly zero. This is due to large elasticity of FRP rods and cavitation of the pump. An effective plunger stroke (relate to the production rate) fluctuates markedly with fluctuations of the dynamical level because of high elasticity. Production capacity of the well is grasped accurately then submergence is kept to be a constant level, and an improved gas anchor is installed for measures against gas lock. Thus, stable production is achieved even with fluctuations of the dynamical level, as well as the increase of the production rate, the plunger stroke is not changed (if anything, it is longer than that of the steel rod). 2 refs., 7 figs., 3 tabs.

  6. Outage capacity and outage rate performance of MIMO free-space optical system over strong turbulence channel

    Science.gov (United States)

    Hasan, Omar M.; Taha, Mohamed; Abu Sharkh, Osama

    2016-06-01

    In this paper, we investigate outage capacity, outage probability, and outage rate performance of multiple-input multiple-output (MIMO) free-space optical system operating over strong turbulence channels. The MIMO optical system employs intensity modulation direct detection with on-off signaling, and equal gain combining technique at the receiver. We derived novel closed-form expressions for three system metrics, namely, outage capacity, outage probability, and outage rate. Expressions derived here are based on the generalized Gamma-Gamma channel model, which is based on scintillation theory that assumes that the irradiance of the received optical wave is modeled as the product of small-scale and large-scale turbulence eddies. The results are evaluated for different values of received signal-to-noise ratios, strong turbulence conditions, and several values of transmit/receive diversity.

  7. Development of Improved Graphical Displays for an Advanced Outage Control Center, Employing Human Factors Principles for Outage Schedule Management

    Energy Technology Data Exchange (ETDEWEB)

    St Germain, Shawn Walter [Idaho National Lab. (INL), Idaho Falls, ID (United States); Farris, Ronald Keith [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thomas, Kenneth David [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    The long-term viability of existing nuclear power plants in the United States (U.S.) is dependent upon a number of factors, including maintaining high capacity factors, maintaining nuclear safety, and reducing operating costs, particularly those associated with refueling outages. Refueling outages typically take 20-30 days, and for existing light water NPPs in the U.S., the reactor cannot be in operation during the outage. Furthermore, given that many NPPs generate between $1-1.5 million/day in revenue when in operation, there is considerable interest in shortening the length of refueling outages. Yet refueling outages are highly complex operations, involving multiple concurrent and dependent activities that are somewhat challenging to coordinate; therefore, finding ways to improve refueling outage performance, while maintaining nuclear safety has proven to be difficult. The Advanced Outage Control Center (AOCC) project is a research and development (R&D) demonstration activity under the LWRS Program. LWRS is an R&D program that works closely with industry R&D programs to establish technical foundations for the licensing and managing of long-term, safe, and economical operation of current fleet of NPPs. As such, the LWRS Advanced Outage Control Center project has the goal of improving the management of commercial NPP refueling outages. To accomplish this goal, INL is developing an advanced outage control center (OCC) that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. The overall focus is on developing an AOCC with the following capabilities that enables plant and OCC staff to; Collaborate in real-time to address emergent issues; Effectively communicate outage status to all workers involved in the outage; Effectively communicate discovered conditions in the field to the OCC; Provide real-time work status; Provide automatic pending support notifications

  8. Development of Improved Graphical Displays for an Advanced Outage Control Center, Employing Human Factors Principles for Outage Schedule Management

    International Nuclear Information System (INIS)

    The long-term viability of existing nuclear power plants in the United States (U.S.) is dependent upon a number of factors, including maintaining high capacity factors, maintaining nuclear safety, and reducing operating costs, particularly those associated with refueling outages. Refueling outages typically take 20-30 days, and for existing light water NPPs in the U.S., the reactor cannot be in operation during the outage. Furthermore, given that many NPPs generate between $1-1.5 million/day in revenue when in operation, there is considerable interest in shortening the length of refueling outages. Yet refueling outages are highly complex operations, involving multiple concurrent and dependent activities that are somewhat challenging to coordinate; therefore, finding ways to improve refueling outage performance, while maintaining nuclear safety has proven to be difficult. The Advanced Outage Control Center (AOCC) project is a research and development (R&D) demonstration activity under the LWRS Program. LWRS is an R&D program that works closely with industry R&D programs to establish technical foundations for the licensing and managing of long-term, safe, and economical operation of current fleet of NPPs. As such, the LWRS Advanced Outage Control Center project has the goal of improving the management of commercial NPP refueling outages. To accomplish this goal, INL is developing an advanced outage control center (OCC) that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. The overall focus is on developing an AOCC with the following capabilities that enables plant and OCC staff to; Collaborate in real-time to address emergent issues; Effectively communicate outage status to all workers involved in the outage; Effectively communicate discovered conditions in the field to the OCC; Provide real-time work status; Provide automatic pending support notifications

  9. Reducing outage times: a FROG perspective

    International Nuclear Information System (INIS)

    In 1992, the Framatome Owners Group (FROG) was set up. It provides a forum for the members, who are all users of Framatome nuclear steam supply systems, to share and benefit from each others experience. Joint activities have been focused on safety and economic performance. Through effective control of outage duration, the average capability factor for the 60 plus nuclear units operated by the members rose from 74% in 1992 to 81.5% in 1993, while the average unplanned capability loss factor reduced from 9% to 3.5%. The specific measures now being taken by three FROG members to improve these results still further are described. The members concerned are Electrabel of Belgium, Electrite de France and the Korea Electric Power Co. (UK)

  10. Kozloduy NPP units 5 and 6 modernization program. Measures implementation in outages

    International Nuclear Information System (INIS)

    The units 5 and 6 modernization program is a highly demanding program composed by many plant modifications and studies about plant conditions. The program measures implementation during the units outages represents a challenge by the need to compromise shut down duration with the workload related to measures installation. The units shutdown duration should be kept to the planned duration. In parallel, contractors work has to be organized, planned and performed to allow successful measures completion. In accordance with the contract requirements, contractors prepare installation documents which comprise all activities to be performed during the installation and testing of the measures. The subcontractors complement these installation documents with the project organization and execution documents, which include the manpower skills, qualifications, work orders, and other important installation instructions and information. Contractors prepared detailed installation schedules, and these were integrated by Parsons E and C in the Integrated installation schedule. The integrated schedule proved to be useful to identify possible area usage conflicts and manpower overlapping, with appropriate results for electrical, instrumentation and control work, and for the utilization of the polar crane in the containment building. Contractors installation schedules were updated on a weekly basis, showing variances versus the target, and manpower histograms for the resource loading. Organization of contractors work was supported by KNPP plant outage meetings, in which status and problems were addressed, and solution and/or corrective actions defined for further implementation. KNPP meetings were planned on a daily basis for most relevant or critical measures, or on a weekly basis for less intensive measures. KNPP meetings proved to be an excellent communication tool for keeping the measures under control and monitoring KNPP defined personnel responsible for authorizing changes, in

  11. Investigation of rectangular concrete columns reinforced or prestressed with fiber reinforced polymer (FRP) bars or tendons

    Science.gov (United States)

    Choo, Ching Chiaw

    Fiber reinforced polymer (FRP) composites have been increasingly used in concrete construction. This research focused on the behavior of concrete columns reinforced with FRP bars, or prestressed with FRP tendons. The methodology was based the ultimate strength approach where stress and strain compatibility conditions and material constitutive laws were applied. Axial strength-moment (P-M) interaction relations of reinforced or prestressed concrete columns with FRP, a linearly-elastic material, were examined. The analytical results identified the possibility of premature compression and/or brittle-tension failure occurring in FRP reinforced and prestressed concrete columns where sudden and explosive type failures were expected. These failures were related to the rupture of FRP rebars or tendons in compression and/or in tension prior to concrete reaching its ultimate strain and strength. The study also concluded that brittle-tension failure was more likely to occur due to the low ultimate tensile strain of FRP bars or tendons as compared to steel. In addition, the failures were more prevalent when long term effects such as creep and shrinkage of concrete, and creep rupture of FRP were considered. Barring FRP failure, concrete columns reinforced with FRP, in some instances, gained significant moment resistance. As expected the strength interaction of slender steel or FRP reinforced concrete columns were dependent more on column length rather than material differences between steel and FRP. Current ACI minimum reinforcement ratio for steel (rhomin) reinforced concrete columns may not be adequate for use in FRP reinforced concrete columns. Design aids were developed in this study to determine the minimum reinforcement ratio (rhof,min) required for rectangular reinforced concrete columns by averting brittle-tension failure to a failure controlled by concrete crushing which in nature was a less catastrophic and more gradual type failure. The proposed method using rhof

  12. Application of RCM analysis to the optimization of outages

    International Nuclear Information System (INIS)

    Considerations to be made before starting RCM analyses at selected systems of the Dukovany-3 reactor unit are discussed. Such systems should be selected where a shortening of their planned maintenance during outages could affect the total length of the outage period. (P.A.)

  13. Elimination of maintenance outage and cost reduction by development of outage-free maintenance techniques

    International Nuclear Information System (INIS)

    The development program of KEPCO on outage-free maintenance techniques for distribution line work since 1984 is overviewed. It has succeeded in eliminating maintenance outages since 1989. The original aim was to improve customer satisfaction. However, in all, four benefits were realised through the development. These are cost reduction, securing of worker safety, improvement of customer service, and advancement of distribution techniques and morale in KEPCO. The introduction of robotic techniques for maintenance work and manipulator techniques for repair work is planned for further modernization. These new techniques are helping in both work safety and work efficiency improvement. Cost reduction and advancement of distribution line work techniques is also considered. (R.P.)

  14. Analytical and Numerical Modelling of FRP Debonding from Concrete Substrate under Pure Shearing

    Institute of Scientific and Technical Information of China (English)

    PAN Jinlong; XU Zhun; C K Y Leung; LI Zongjin

    2012-01-01

    External bonding of fiber reinforced polymer (FRP) composites on the concrete structures has been proved to be an effective and efficient way to strengthen concrete structures.For a FRP strengthened concrete beam,it is usually observed that the failure occurs in the concrete and a thin layer of concrete is attached on the surface of the debonded FRP plate.To study the debond behavior between concrete and FRP composites,an analytical model based on the three-parameter model is developed to study the debonding behavior for the FRP-to-concrete joint under pure shearing.Then,nonlinear FEM analysis is conducted to verify the proposed analytical model.The FEM results shows good agreement with the results from the model.Finally,with the analytical model,sensitivity analyses are performed to study the effect of the interfacial parameters or the geometric parameters on the debonding behavior.

  15. Behavior of FRP-Confined Concrete-Filled Steel Tube Columns

    Directory of Open Access Journals (Sweden)

    Yiyan Lu

    2014-05-01

    Full Text Available This paper presents the results of an experimental study into the behavior of concrete-filled steel tube columns confined by fiber-reinforced polymer (FRP. Eleven columns were tested to investigate the effects of the FRP layer number, the thickness of the steel tube and concrete strength on their load capacity and axial deformation capacity. The experimental results indicated that the FRP wrap can effectively confine the concrete expansion and delay the local buckling of the steel tube. Both the load capacity and the axial deformation capacity of concrete-filled steel tube columns can be substantially enhanced with FRP confinement. A model is proposed to predict the load capacity of the FRP-confined concrete-filled steel tube columns. The predicted results are generally in good agreement with the experimental ones obtained in this study and in the literature.

  16. Shaking Table Tests on RC Retrofitted Frame with FRP

    OpenAIRE

    Chaudat, T.; Pilakoutas, K.; Papastergiou, P.; Ciupala, M.A.

    2006-01-01

    This paper describes the experimental work undertaken on FRP seismic strengthening of a RC structure as part of the “Ecoleader” European program. Shaking table tests were performed on a one-bay, 2 storey, full-scale spatial RC-frame (4 m x 4 m, 6.6 m high, 30 t mass) at CEA Saclay on the AZALEE shaking table. Two further papers in this conference will describe the analytical work relating to the tests. The main objective of the program was to assess different strengthening strategies and tech...

  17. Behaviour of FRP confined concrete in square columns

    Directory of Open Access Journals (Sweden)

    de Diego, A.

    2015-12-01

    Full Text Available A significant amount of research has been conducted on FRP-confined circular columns, but much less is known about rectangular/square columns in which the effectiveness of confinement is much reduced. This paper presents the results of experimental investigations on low strength square concrete columns confined with FRP. Axial compression tests were performed on ten intermediate size columns. The tests results indicate that FRP composites can significantly improve the bearing capacity and ductility of square section reinforced concrete columns with rounded corners. The strength enhancement ratio is greater the lower the concrete strength and also increases with the stiffness of the jacket. The confined concrete behaviour was predicted according to the more accepted theoretical models and compared with experimental results. There are two key parameters which critically influence the fitting of the models: the strain efficiency factor and the effect of confinement in non-circular sections.La mayoría de las investigaciones sobre hormigón confinado con FRP se han realizado sobre pilares de sección circular, pero el comportamiento en secciones cuadradas/rectangulares, donde el confinamiento es menos eficaz, es mucho menos conocido. Este trabajo presenta los resultados de un estudio experimental sobre probetas de hormigón de baja resistencia y sección cuadrada. Se han ensayado a compresión centrada diez probetas de tamaño intermedio. Los resultados indican que el confinamiento mejora significativamente la resistencia y ductilidad del hormigón en columnas de sección cuadrada con las esquinas redondeadas. El incremento de resistencia es mayor cuanto menor es la resistencia del hormigón sin confinar y también aumenta con la rigidez del encamisado. Los resultados se compararon con los obtenidos según los modelos teóricos más aceptados. Hay dos parámetros críticos en el ajuste de los modelos: el factor de eficiencia de la deformación y el

  18. Fire performance of basalt FRP mesh reinforced HPC thin plates

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup;

    2013-01-01

    An experimental program was carried out to investigate the influence of basalt FRP (BFRP) reinforcing mesh on the fire behaviour of thin high performance concrete (HPC) plates applied to sandwich elements. Samples with BFRP mesh were compared to samples with no mesh, samples with steel mesh and...... samples displaying a full sandwich structure. Final results confirmed the bond loss between concrete and BFRP mesh with temperature. The available void where the epoxy burnt away allowed the concrete matrix to release pressure and limit pore stresses, delaying spalling. It also reduced the mechanical...

  19. Estructuras de hormigón pretensado armadas con FRP

    OpenAIRE

    GARCÍA POLO, JOSÉ MANUEL

    2013-01-01

    El objetivo del presente Proyecto Final de Carrera (PFC) es la actualización del estado de la cuestión en el campo del uso de hormigón pretensado con barras de refuerzo formadas por materiales compuestos a base de fibras de carbono, aramidas o vidrio y una matriz formada por resinas poliméricas a base de poliéster, vinyil éster o epoxi, conocidas como barras FRP (Fiber Reinforced Polymer), designándose CFRP, AFRP y GFRP, según sean de carbono, aramidas o vidrio respectivamente. La consecución...

  20. RESEARCH ON KEY TECHNOLOGY IN CONSTRUCTING FRP-STEEL COMPOSITE BRIDGE%FRP-钢组合结构桥梁建造关键技术研究

    Institute of Scientific and Technical Information of China (English)

    朱坤宁; 万水

    2011-01-01

    FRP-钢组合结构公路桥研制过程中的关键技术进行了研究,通过GFRP桥面板的设计与加工、有限元分析和试验研究,研制出适用于我国公路桥梁用的重型FRP桥面板.将GFRP桥面板与波形腹板H型钢梁组合起来,建成我国第一座FRP-钢组合结构公路桥.对GFRP-钢组合结构公路桥梁结构进行成桥荷载试验.试验结果表明,FRP-钢组合结构桥梁处于安全受力状态,满足设计荷载下的使用要求.%The construction technology of FRP-steel composite bridge is researched through the development process. The FRP bridge deck that used in bridge structure is developed through the design and fabricate, as well as the finite element analysis and experimental research of GFRP bridge deck. And the first FRP-steel composite bridge in China is built with GFRP bridge deck and steel H girder with corrugated web. Load test of the composite bridge is made, and the result shows that the structure is in a safe state and meets the requirements under the design load.

  1. RESEARCH ON KEY TECHNOLOGY IN CONSTRUCTING FRP-STEEL COMPOSITE BRIDGE%FRP-钢组合结构桥梁建造关键技术研究

    Institute of Scientific and Technical Information of China (English)

    朱坤宁; 万水

    2011-01-01

    The construction technology of FRP-steel composite bridge is researched through the development process. The FRP bridge deck that used in bridge structure is developed through the design and fabricate, as well as the finite element analysis and experimental research of GFRP bridge deck. And the first FRP-steel composite bridge in China is built with GFRP bridge deck and steel H girder with corrugated web. Load test of the composite bridge is made, and the result shows that the structure is in a safe state and meets the requirements under the design load.%对FRP-钢组合结构公路桥研制过程中的关键技术进行了研究,通过GFRP桥面板的设计与加工、有限元分析和试验研究,研制出适用于我国公路桥梁用的重型FRP桥面板.将GFRP桥面板与波形腹板H型钢梁组合起来,建成我国第一座FRP-钢组合结构公路桥.对GFRP-钢组合结构公路桥梁结构进行成桥荷载试验.试验结果表明,FRP-钢组合结构桥梁处于安全受力状态,满足设计荷载下的使用要求.

  2. A comparison of FRP-sandwich penetrating impact test methods

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrand, M. [VTT Manufacturing Technology, Espoo (Finland). Maritime and Mechanical Engineering

    1996-12-31

    The main objective of this project is to identify the test methods which provide useful results for the different types of penetrating impacts occurring in sandwich structures. A series of penetrating impact tests on FRP-sandwich panels is performed using three different test methods and the results of the test methods are compared. The test methods used are the standardised method ISO 6603 and two non-standardised methods. The first non-standardised method uses a pyramid-shaped impactor instead of the cylindrical impactor used in the ISO 6603 method. In the second non-standardised method, the impact test is performed quasistatically using a cylindrical impactor. Possible stages of failure occurring in FRP-sandwich during a penetrating impact are illustrated. A comprehensive test method should be able to provoke various failure modes, as observed in impact failures of actual sandwich structures. The results obtained with the three test methods lead to a different ranking in impact strength of the panels. Hence, impact test results obtained with different test methods are not even qualitatively comparable. The pyramid-shaped impactor is able to generate clearly more failure modes than the cylindrical impactor in the ISO 6603 method. Therefore, it is considered to be of more practical value for determining the impact strength of PRP-sandwich structures. (orig.) (15 refs.)

  3. Technology Integration Initiative In Support of Outage Management

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Weatherby; David Gertman

    2012-07-01

    Plant outage management is a high priority concern for the nuclear industry from cost and safety perspectives. Often, command and control during outages is maintained in the outage control center where many of the underlying technologies supporting outage control are the same as those used in the 1980’s. This research reports on the use of advanced integrating software technologies and hand held mobile devices as a means by which to reduce cycle time, improve accuracy, and enhance transparency among outage team members. This paper reports on the first phase of research supported by the DOE Light Water Reactor Sustainability (LWRS) Program that is performed in close collaboration with industry to examine the introduction of newly available technology allowing for safe and efficient outage performance. It is thought that this research will result in: improved resource management among various plant stakeholder groups, reduced paper work, and enhanced overall situation awareness for the outage control center management team. A description of field data collection methods, including personnel interview data, success factors, end-user evaluation and integration of hand held devices in achieving an integrated design are also evaluated. Finally, the necessity of obtaining operations cooperation support in field studies and technology evaluation is acknowledged.

  4. Discontinuous Brillouin strain monitoring of small concrete bridges: comparison between near-to-surface and smart FRP fiber installation techniques

    Science.gov (United States)

    Bastianini, Filippo; Rizzo, Andrea; Galati, Nestore; Deza, Ursula; Nanni, Antonio

    2005-05-01

    Brillouin fiber optic sensing is a promising technology for Structural Health Monitoring (SHM) whose diffusion is however at present reduced by the unavailability of proper sensor products and established installation techniques specifically aimed at the building industry. Due to its intrinsic distributed sensing capability, Brillouin systems can individually measure the deformation of any single segment of considerable lengths of single-mode fiber. In addition, Brillouin retains all the other typical advantages of Fiber Optic Sensors (FOS), such as harsh environment durability and electro-magnetic interference rejection. These advantages, especially considering that the required sensors are really low cost, make the system particularly attractive for periodical ("discontinuous") strain monitoring of unattended infrastructures that might be exposed to ageing and vandalism damages. Despite the high equipment cost, the technique can become economically convenient when the same initial investment can be amortized over a number of applications that can be monitored periodically using the same device. This work presents a comparison between two different Brillouin sensor installation techniques: Near-to-Surface Fiber (NSF) embedding and smart-FRP sensor bonding. Both systems have been experimented in the field on small Reinforced Concrete (RC) bridges subject to a diagnostic load test. The obtained results clearly highlight the advantages of the smart-FRP system, in terms of performance enhancements, installation cost, and time reduction.

  5. Role of shutdown PRA in outage planning

    International Nuclear Information System (INIS)

    As part of the ABWR shutdown risk evaluation, a reliability assessment of the decay heat removal (DHR) function was completed to determine the minimum number of systems that must be kept available during shutdown to ensure that the risks associated with the loss of decay heat removal events are acceptable. The selected criteria for the study is a conditional core damage probability of 1.0E-05. The analysis was carried out by developing probabilistic risk assessment (PRA) models for shutdown conditions. The plant is assumed to be initially shutdown with the decay heat being removed by the residual heat removal (RHR) system in the shutdown cooling mode. Loss of the operating RHR system due to random failure, loss of service water, and loss of offsite power are assumed to be the initiating events. The results of this study provide guidance regarding various combinations of systems that can be kept available during a plant outage, to ensure acceptable risk associated with loss of the DHR systems. This minimum set of systems will give a utility flexibility in scheduling maintenance activities for DHR systems. This PRA-based approach could be easily extended to operating BWR plants using information available from the operating plant IPE

  6. Building

    OpenAIRE

    Seavy, Ryan

    2014-01-01

    Building for concrete is temporary. The building of wood and steel stands against the concrete to give form and then gives way, leaving a trace of its existence behind. Concrete is not a building material. One does not build with concrete. One builds for concrete.

  7. Biaxial Flexural Strength and Estimation of Size on the Strength Properties of FRP Composites

    Directory of Open Access Journals (Sweden)

    M. N. Saraf

    1990-04-01

    Full Text Available Fibre reinforced plastics (FRP are widely used as structural materials. For designing structural components, a designer is provided with data based on unidirectional testing. But in real structural applications the component is subjected to multiaxial stress throughout the material. Hence a multiaxial test is a better gauge of the behaviour of FRP components in service. In the present paper a ring-on-ring method was adopted which produces biaxial flexural stress on the FRP specimen. Wubull's statistical weakest link theory was applied to standardize the complexity and to assess the reliability of the results.

  8. Anchorage Failure of RC beams strengthened with FRP at the bottom face

    DEFF Research Database (Denmark)

    Täljsten, Björn; Arifovic, Fedja

    2009-01-01

    When RC beams are strengthened by FRP plates bonded to the bottom face of the beam they fail due to the lack of the mechanical anchorage of the plate. This paper shows that it is possible to relate the anchorage failure of tension face FRP-plated beams to the crack sliding capacity of the beams...... load of tension face plated beams. The assumption is that the FRP-plate must be extended at least one critical anchorage length beyond the theoretical occurrence of the critical diagonal crack....

  9. Good practices for outage management in nuclear power plants

    International Nuclear Information System (INIS)

    As a follow-up to an earlier Technical Document on Good Practices for Improved Nuclear Power Plant Performance (IAEA-TECDOC-498), the Agency has produced a more focused technical report on good practices associated with nuclear power plant outage planning and execution. As with the earlier document, the overall aim is that by identifying good practices in the key aspects of outage management, overall world nuclear performance will improve and the gap between excellent performers and operators with developing programmes will be narrowed. This document has been produced through the contribution of numerous operators and government agencies. It aims at minimizing text and focusing on actual good practices in use which can be found in the annexes. While the specific methods used to achieve excellence in maintenance/refuelling outages may differ, the fundamental requirements of outage management are discussed

  10. Risk informed decision making for the allowed outage times changes

    International Nuclear Information System (INIS)

    The paper describes the methods for risk informed evaluation of the allowed outage times. Applications of the methods are also provided for the safety related equipment of the J. Bohunice V2 NPP. (author)

  11. Risk informed decision making for the allowed outage times changes

    International Nuclear Information System (INIS)

    The paper describes the methods for risk informed evaluation of the allowed outage times. Applications of the methods are also provided for the safety related equipment of the J.Bohunice V2 NPP. (author)

  12. Follow up of the PWRs maintenance outages in France

    International Nuclear Information System (INIS)

    This paper describes the general frame of the follow-up of the PWRs maintenance outages by the DRIREs (Regional Directorates for Industry, Research and the Environment) in France, with respect to the enforcement of several regulations (including the quality assurance order of 1984), but also to the compliance with the general operating rules for EDF plants. Maintenance as well as reactor operation activities during outages are considered by the DRIREs, and more particularly the pressure vessel regulation, the equipment important for safety, the outage preparation, the real time follow-up, the completion of outage. A few examples of recent events or incidents, involving human factors and organisation aspects, are given. They stress the importance of safety culture, training as well as experience feedback for the different actors

  13. Outage performance of cognitive radio systems with Improper Gaussian signaling

    KAUST Repository

    Amin, Osama

    2015-06-14

    Improper Gaussian signaling has proved its ability to improve the achievable rate of the systems that suffer from interference compared with proper Gaussian signaling. In this paper, we first study impact of improper Gaussian signaling on the performance of the cognitive radio system by analyzing the outage probability of both the primary user (PU) and the secondary user (SU). We derive exact expression of the SU outage probability and upper and lower bounds for the PU outage probability. Then, we design the SU signal by adjusting its transmitted power and the circularity coefficient to minimize the SU outage probability while maintaining a certain PU quality-of-service. Finally, we evaluate the proposed bounds and adaptive algorithms by numerical results.

  14. Multicast Outage Probability and Transmission Capacity of Multihop Wireless Networks

    CERN Document Server

    Liu, Chun-Hung

    2010-01-01

    Multicast transmission, wherein the same packet must be delivered to multiple receivers, is an important aspect of sensor and tactical networks and has several distinctive traits as opposed to more commonly studied unicast networks. Specially, these include (i) identical packets must be delivered successfully to several nodes, (ii) outage at any receiver requires the packet to be retransmitted at least to that receiver, and (iii) the multicast rate is dominated by the receiver with the weakest link in order to minimize outage and retransmission. We utilize a Poisson cluster process consisting of a distinct Poisson point process (PPP) for the transmitters and receivers, and then define the multicast transmission capacity (MTC) as the maximum achievable multicast rate times the number of multicast clusters per unit volume (area for $d=2$), accounting for outages and retransmissions. A multicast cluster is a contiguous volume (area) over which a packet is multicasted, and to reduce outage it can be tessellated i...

  15. Fessenheim makes the most of its ten year outage

    International Nuclear Information System (INIS)

    EdF took advantage of the long shutdown opportunity during its Fessenheim 1 ten year outage (April to October 1989) to carry out a number of tests and modifications additional to normal outage operations. The major activities incorporated in this outage were: both normal outage operations and unscheduled operations carried out in response to problems found after inspections had been carried out; a reactor coolant pressure boundary hydro test, to comply with French regulations; a containment test (a mandatory safety requirement); 147 modifications, carried out as part of the 900MWe series upgrading programme; additional design studies initiated by EdF upon request from the Nuclear Facility Central Surveillance Service (SCSIN). (author)

  16. SAMPLE RESULTS FROM MCU SOLIDS OUTAGE

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T.; Washington, A.; Oji, L.; Coleman, C.; Poirier, M.

    2014-09-22

    Savannah River National Laboratory (SRNL) has received several solid and liquid samples from MCU in an effort to understand and recover from the system outage starting on April 6, 2014. SRNL concludes that the presence of solids in the Salt Solution Feed Tank (SSFT) is the likely root cause for the outage, based upon the following discoveries  A solids sample from the extraction contactor #1 proved to be mostly sodium oxalate  A solids sample from the scrub contactor#1 proved to be mostly sodium oxalate  A solids sample from the Salt Solution Feed Tank (SSFT) proved to be mostly sodium oxalate  An archived sample from Tank 49H taken last year was shown to contain a fine precipitate of sodium oxalate  A solids sample from the extraction contactor #1 drain pipe from extraction contactor#1 proved to be mostly sodium aluminosilicate  A liquid sample from the SSFT was shown to have elevated levels of oxalate anion compared to the expected concentration in the feed Visual inspection of the SSFT indicated the presence of precipitated or transferred solids, which were likely also in the Salt Solution Receipt Tank (SSRT). The presence of the solids coupled with agitation performed to maintain feed temperature resulted in oxalate solids migration through the MCU system and caused hydraulic issues that resulted in unplanned phase carryover from the extraction into the scrub, and ultimately the strip contactors. Not only did this carryover result in the Strip Effluent (SE) being pushed out of waste acceptance specification, but it resulted in the deposition of solids into several of the contactors. At the same time, extensive deposits of aluminosilicates were found in the drain tube in the extraction contactor #1. However it is not known at this time how the aluminosilicate solids are related to the oxalate solids. The solids were successfully cleaned out of the MCU system. However, future consideration must be given to the exclusion of oxalate solids into

  17. Development of Methodologies for Technology Deployment for Advanced Outage Control Centers that Improve Outage Coordination, Problem Resolution and Outage Risk Management

    Energy Technology Data Exchange (ETDEWEB)

    Shawn St. Germain; Ronald Farris; Heather Medeman

    2013-09-01

    This research effort is a part of the Light-Water Reactor Sustainability (LWRS) Program, which is a research and development (R&D) program sponsored by Department of Energy (DOE) and performed in close collaboration with industry R&D programs that provides the technical foundations for licensing and managing the long-term, safe, and economical operation of current nuclear power plants. The LWRS program serves to help the U.S. nuclear industry adopt new technologies and engineering solutions that facilitate the continued safe operation of the plants and extension of the current operating licenses. The long term viability of existing nuclear power plants in the U.S. will depend upon maintaining high capacity factors, avoiding nuclear safety issues and reducing operating costs. The slow progress in the construction on new nuclear power plants has placed in increased importance on maintaining the output of the current fleet of nuclear power plants. Recently expanded natural gas production has placed increased economic pressure on nuclear power plants due to lower cost competition. Until recently, power uprate projects had steadily increased the total output of the U.S. nuclear fleet. Errors made during power plant upgrade projects have now removed three nuclear power plants from the U.S. fleet and economic considerations have caused the permanent shutdown of a fourth plant. Additionally, several utilities have cancelled power uprate projects citing economic concerns. For the past several years net electrical generation from U.S. nuclear power plants has been declining. One of few remaining areas where significant improvements in plant capacity factors can be made is in minimizing the duration of refueling outages. Managing nuclear power plant outages is a complex and difficult task. Due to the large number of complex tasks and the uncertainty that accompanies them, outage durations routinely exceed the planned duration. The ability to complete an outage on or near

  18. Mast sipping technique optimises refueling outages

    International Nuclear Information System (INIS)

    Innovative inspection systems from FRAMATOME ANP can significantly contribute towards shortening the time needed for refueling outages. Mast sipping is a technique which provides fast information on the condition of fuel assemblies scheduled for further use in the reactor core. FRAMATOME ANP is going to deliver a mast sipping system for Kozloduy 440 VVER units, to identify leaking fuel assemblies. Whereas in some other VVER 440 plants the sipping test has normally been performed to date with a sipping hood placed on the top of the fuel assemblies in the core before unloading them to the spent fuel storage pool, today the sipping test can be performed as the fuel assemblies are being removed from the reactor. This new method can save time and permits the condition of a fuel assembly to be identified at the earliest possible point in time. The mast sipping procedure makes use of the reduction in pressure which occurs when fuel assemblies are lifted out of the reactor pressure vessel, the resulting pressure difference al-lowing water-soluble or gaseous fission products to be released from defective fuel rods. During the movement of the fuel assembly by the refueling machine, water is extracted from the refueling machine mast in the vicinity of the fuel assembly and analyzed for the presence of fission products. Gaseous fission products (xenon and krypton) are separated from the water, dried and routed to a scintillation detector. The measured data are analysed immediately after sampling. A water sample is taken in parallel which can be analysed in the radio-chemical laboratory to provide a reference measurement. The data obtained from the sample measurements are immediately evaluated. The results are displayed on screen and the data stored in a text file. The mast sipping system has been qualified in several German PWR plants during refueling with excellent results. In the mean time Mast Sipping is considered as a standard procedure in nuclear power plants of Germany

  19. Evolution of an outage management organization in a small utility

    International Nuclear Information System (INIS)

    Six refueling outages with a number of major equipment failure outages have taught Rancho Seco management three main items. One is that a dedicated management organization must be formed for the purpose of controlling work functions at Rancho Seco. This dedicated organization must have the experience of the plant and not have the responsibility for the actual maintenance. Second, upper management within a power plant must get directly involved in the outage. Upper management must show their presence, give input, and be available when needed. The third item learned is that the scheduling organization must be adequately staffed. Although Rancho Seco completed a refueling outage in 1978 within only 36 days, additional inspection requirements due to regulatory changes and/or previous equipment failures requiring follow-up actions would place the shortest possible outage today at approx.70 days. The only way an organization can keep this outage time down is with the proper scheduling of the resources and the timely coordination of activities to reduce conflicts

  20. 3D Numerical Realization of FRP Mircrostructure from High-Res X-Ray CT Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Currently, characterization of constituent-level failure in state-of-the-art FRP composites is limited to two-dimensional observations (e.g. using optical or...

  1. Structural Performance of Light Weight Multicellular FRP Composite Bridge Deck Using Finite Element Analysis

    Institute of Scientific and Technical Information of China (English)

    Woraphot Prachasaree; Pongsak Sookmanee

    2012-01-01

    Fiber reinforced polymer (FRP) composite materials having advantages such as higher strength to weight than conventional engineering materials,non-corrosiveness and modularization,which should help engineers to obtain more efficient and cost effective structural materials and systems.Currently,FRP composites are becoming more popular in civil engineering applications.The objectives of this research are to study performance and behavior of light weight multi-cellular FRP composite bridge decks (both module and system levels) under various loading conditions through finite element modeling,and to validate analytical response of FRP composite bridge decks with data from laboratory evaluations.The relative deflection,equivalent flexural rigidity,failure load (mode) and load distribution factors (LDF) based on FE results have been compared with experimental data and discussed in detail.The finite element results showing good correlations with experimental data are presented in this work.

  2. Effects of RC beams reinforcement using near surface mounted reinforced FRP composites

    Directory of Open Access Journals (Sweden)

    Ranković Slobodan

    2010-01-01

    Full Text Available This paper analyzes application of modern reinforcement methods for reinforced concrete (RC beams using fiber-reinforced polymer (FRP materials. Basic characteristics of FRP materials and the method of mounting the FRP bars within concrete, that is, near the surface of the beams (NSM method are presented. The properties of this method and its advantages in comparison to externally bonded reinforcement laminate method (EBR have been analyzed. The results of measured deflections and width of the cracks of the beams reinforced by FRP bars, depending on the load are presented and discussed, in comparison to the results obtained from the non-reinforced beams. The experimental research was published at the Faculty of Civil Engineering and Architecture of Niš in 2009.

  3. Mechanical Behaviour and Durability of FRP-to-steel Adhesively-bonded Joints

    OpenAIRE

    Jiang, X.

    2013-01-01

    During the last two decades, fiber-reinforced polymer (FRP) bridge decks have been increasingly used as a competitive alternative for wood, concrete and orthotropic steel decks, due to their various advantages: light-weight, good corrosion resistance, low maintenance cost and rapid installation for minimizing the traffic disturbing time. These advantages meet critical needs for rehabilitation and new construction of pedestrian and highway bridges. To be cost effective, FRP decks are usually s...

  4. Backbone resonance assignments of the outer membrane lipoprotein FrpD from Neisseria meningitidis

    Czech Academy of Sciences Publication Activity Database

    Bumba, Ladislav; Sviridova, E.; Kutá-Smatanová, Ivana; Řezáčová, Pavlína; Veverka, Václav

    2014-01-01

    Roč. 8, č. 1 (2014), s. 53-55. ISSN 1874-2718 R&D Projects: GA ČR(CZ) GAP207/11/0717; GA MŠk(CZ) LK11205 Institutional support: RVO:61388963 ; RVO:61388971 ; RVO:67179843 Keywords : Neisseria meningitidis * FrpC * FrpD * backbone assignments * NMR * iron-regulated protein Subject RIV: CE - Biochemistry Impact factor: 0.760, year: 2014

  5. Effects of Aspect Ratio on the Observed Hoop Strain Variation in FRP Confined Concrete Cylinders

    OpenAIRE

    Bisby, L. A.; Sinclair, D; Webster, M.; Stratford, T. J.; Take, W.A.

    2009-01-01

    Confinement of circular concrete columns by circumferential fibre reinforced polymer (FRP) wraps is among the most widely implemented applications of FRP materials for infrastructure. FRPs are wrapped in the hoop direction around the perimeter of concrete columns and bonded in place with an epoxy adhesive; the effect of this is to drastically improve the columns’ strength and deformability, which has clear benefits for axial strengthening, seismic enhancement, and blast damage mitigation. The...

  6. Prediction and experimental characterization of the molecular architecture of FRP and ATRP synthesized polyacrylate networks

    OpenAIRE

    Gonçalves, Miguel; Dias, Rolando; Costa, Mário Rui

    2010-01-01

    This work reports experimental and modeling studies concerning the conventional (FRP) and atom transfer radical polymerization (ATRP) of acrylate/diacrylate monomers. In the framework of a recently developed general approach, kinetic models including crosslinking reactions and branching by chain transfer to polymer are discussed for FRP and ATRP polymerization systems. Besides molecular weight distribution (MWD), fairly good predictions of the z-average radius of gyration could be obtained fo...

  7. FRP-RC Beam in Shear: Mechanical Model and Assessment Procedure for Pseudo-Ductile Behavior

    OpenAIRE

    Floriana Petrone; Giorgio Monti

    2014-01-01

    This work deals with the development of a mechanics-based shear model for reinforced concrete (RC) elements strengthened in shear with fiber-reinforced polymer (FRP) and a design/assessment procedure capable of predicting the failure sequence of resisting elements: the yielding of existing transverse steel ties and the debonding of FRP sheets/strips, while checking the corresponding compressive stress in concrete. The research aims at the definition of an accurate capacity equation, consisten...

  8. Literature review on reinforced concrete members strengthened with FRP at room and elevated temperature

    OpenAIRE

    Proia, Alessandro; Matthys, Stijn

    2015-01-01

    In the last 30 years, composite materials have been successfully applied as structural reinforcement to strengthen existing structures. The success of applying FRPs (Fibre Reinforced Polymers) for strengthening is due to their excellent mechanical properties and durability, their ease of application and the versatility of FRP strengthening systems. In particular Near Surface Mounted (NSM) reinforcement offers an interesting technology in terms of protection of the FRP from external influences...

  9. Effect of Chloride Content on Bond Behavior Between FRP and Concrete

    Institute of Scientific and Technical Information of China (English)

    潘金龙; 黄毅方; 邢锋

    2010-01-01

    For reinforced concrete structures located along the seaside, the penetration of chloride ions into concrete may be a threat to the durability of the structures. Experimental investigations were carried out to study the effect of chloride content on the bond behavior between concrete and fiber reinforced polymer (FRP) plates. Direct shear tests were conducted on the FRP strengthened concrete members. Before testing, the specimens were immersed in NaCl solutions with concentrations ranging from 3%—15% for di...

  10. Confining concrete with sisal and jute FRP as alternatives for CFRP and GFRP

    Directory of Open Access Journals (Sweden)

    Tara Sen

    2015-12-01

    Full Text Available This research paper presents an experimental investigation on the confinement strength and confinement modulus of concrete cylinders confined using different types of natural fibre composites and a comparative performance analysis with different artificial fibre based composite materials. The paper also highlights the need to switch over from the utilization of artificial fibres, which are non-renewable and fossil fuel products, to environmental beneficial materials like green fibres. The utilization of plant products like sisal and jute fibres and their composites in various structural engineering applications addresses the issues of sustainability and renewability with constructional materials. The paper describes a suitable mechanical treatment method like high temperature conditioning, which aids us in further improving the properties of these woven natural materials like sisal and jute for composite fabrication and utilization. Heat treated natural fibres of woven sisal and jute were utilized for confining concrete cylinders similar to CFRP and GFRP confinement and their confinement characteristics were obtained and compared. All the cylinders were subjected to monotonic axial compressive loads, so as to evaluate the effect of confinement on the axial load carrying capacity and all their failure modes were discussed thoroughly. The results indicated superior performance by sisal FRP as well as jute FRP confined cylinders as compared to controlled or unconfined cylinders, also sisal FRP wrapped cylinders displayed ultimate axial load of comparable magnitude to CFRP confinement. Natural FRP confinement displayed superior confinement modulus and confinement strength, also the ultimate axial load of concrete cylinders confined with natural FRPs underwent 66% enhancement by sisal FRP and 48% enhancement by jute FRP, in comparison with controlled or unconfined cylinders. Enhancement in axial load carrying capacity was 83% with CFRP confinement

  11. Temporary cooling system for critical loads during Recirculation Cooling Water (RCW) system outage

    International Nuclear Information System (INIS)

    As part of the Point Lepreau Refurbishment Project, Recirculation Cooling Water (RCW) system will be shutdown for maintenance activity. During the RCW outage, alternate cooling flow for critical heat loads such as Spent Fuel Bay (SFB), D2O vapour dryers and Instrument Air Compressor Coolers will be provided through a temporary cooling system to remove approximately 3MW of heat. This paper describes a practical strategy to build in the temporary cooling system for this project. Major equipment involved, piping modifications required and system reliability analysis are also addressed. (author)

  12. FRP-RC Beam in Shear: Mechanical Model and Assessment Procedure for Pseudo-Ductile Behavior

    Directory of Open Access Journals (Sweden)

    Floriana Petrone

    2014-07-01

    Full Text Available This work deals with the development of a mechanics-based shear model for reinforced concrete (RC elements strengthened in shear with fiber-reinforced polymer (FRP and a design/assessment procedure capable of predicting the failure sequence of resisting elements: the yielding of existing transverse steel ties and the debonding of FRP sheets/strips, while checking the corresponding compressive stress in concrete. The research aims at the definition of an accurate capacity equation, consistent with the requirement of the pseudo-ductile shear behavior of structural elements, that is, transverse steel ties yield before FRP debonding and concrete crushing. For the purpose of validating the proposed model, an extended parametric study and a comparison against experimental results have been conducted: it is proven that the common accepted rule of assuming the shear capacity of RC members strengthened in shear with FRP as the sum of the maximum contribution of both FRP and stirrups can lead to an unsafe overestimation of the shear capacity. This issue has been pointed out by some authors, when comparing experimental shear capacity values with the theoretical ones, but without giving a convincing explanation of that. In this sense, the proposed model represents also a valid instrument to better understand the mechanical behavior of FRP-RC beams in shear and to calculate their actual shear capacity.

  13. TOPOLOGY AND CASCADING LINE OUTAGES IN POWER GRIDS

    Institute of Scientific and Technical Information of China (English)

    David L. PEPYNE

    2007-01-01

    Motivated by the small world network research of Watts & Strogatz, this paper studies relationships between topology and cascading line outages in electric power grids. Cascading line outages are a type of cascading collapse that can occur in power grids when the transmission network is congested. It is characterized by a self-sustaining sequence of line outages followed by grid breakup, which generally leads to widespread blackout. The main findings of this work are twofold: On one hand, the work suggests that topologies with more disorder in their interconnection topology tend to be robust with respect to cascading line outages in the sense of being able to support greater generation and demand levels than more regularly interconnected topologies. On the other hand, the work suggests that topologies with more disorder tend to be more fragile in that should a cascade get started, they tend to break apart after fewer outages than more regularly interconnected topologies. Thus, as has been observed in other complex networks, there appears to be a tradeoff between robustness and fragility.These results were established using synthetically generated power grid topologies and verified using the IEEE 57 bus and 188 bus power grid test cases.

  14. Outage and Local Throughput and Capacity of Random Wireless Networks

    CERN Document Server

    Haenggi, Martin

    2008-01-01

    Outage probabilities and single-hop throughput are two important performance metrics that have been evaluated for certain specific types of wireless networks. However, there is a lack of comprehensive results for larger classes of networks, and there is no systematic approach that permits the convenient comparison of the performance of networks with different geometries and levels of randomness. The uncertainty cube is introduced to categorize the uncertainty present in a network. The three axes of the cube represent the three main potential sources of uncertainty in interference-limited networks: the node distribution, the channel gains (fading), and the channel access (set of transmitting nodes). For the performance analysis, a new parameter, the so-called {\\em spatial contention}, is defined. It measures the slope of the outage probability in an ALOHA network as a function of the transmit probability $p$ at $p=0$. Outage is defined as the event that the signal-to-interference ratio (SIR) is below a certain...

  15. Outage Risk Assessment and Management (ORAM) thermal-hydraulics toolkit

    International Nuclear Information System (INIS)

    A PC-based thermal-hydraulic toolkit for use in support of outage optimization, management and risk assessment has been developed. This mechanistic toolkit incorporates simple models of key thermal-hydraulic processes which occur during an outage, such as recovery from or mitigation of outage upsets; this includes heat-up of water pools following loss of shutdown cooling, inadvertent drain down of the RCS, boiloff of coolant inventory, heatup of the uncovered core, and reflux cooling. This paper provides a list of key toolkit elements, briefly describes the technical basis and presents illustrative results for RCS transient behavior during reflux cooling, peak clad temperatures for an uncovered core and RCS response to loss of shutdown cooling. (author)

  16. Multicast Capacity Scaling of Wireless Networks with Multicast Outage

    CERN Document Server

    Liu, Chun-Hung

    2010-01-01

    Multicast transmission has several distinctive traits as opposed to more commonly studied unicast networks. Specially, these include (i) identical packets must be delivered successfully to several nodes, (ii) outage could simultaneously happen at different receivers, and (iii) the multicast rate is dominated by the receiver with the weakest link in order to minimize outage and retransmission. To capture these key traits, we utilize a Poisson cluster process consisting of a distinct Poisson point process (PPP) for the transmitters and receivers, and then define the multicast transmission capacity (MTC) as the maximum achievable multicast rate times the number of multicast clusters per unit volume, accounting for outages and retransmissions. Our main result shows that if $\\tau$ transmission attempts are allowed in a multicast cluster, the MTC is $\\Theta\\left(\\rho k^{x}\\log(k)\\right)$ where $\\rho$ and $x$ are functions of $\\tau$ depending on the network size and density, and $k$ is the average number of the inte...

  17. Assessing energy supply security: Outage costs in private households

    International Nuclear Information System (INIS)

    The objective of this paper is to contribute to the topic of energy supply security by proposing a Monte Carlo-based and a survey based model to analyze the costs of power interruptions. Outage cost estimations are particularly important when deciding on investments to improve supply security (e.g. additional transmission lines) in order to compare costs to benefits. But also other policy decisions on measures that have direct or indirect consequences for the supply security (e.g. a phasing out of nuclear energy) need to be based on results from outage cost estimations. The main focus of this paper lies with residential consumers, but the model is applied to commercial, industrial and governmental consumers as well. There are limited studies that have approached the problem of evaluating outage cost. When comparing the results of these studies, they often display a high degree of diversification. As consumers have different needs and dependencies towards the supply of electricity because of varying circumstances and preferences, a great diversity in outage cost is a logical consequence. To take the high degree of uncertainties into account, a Monte Carlo simulation was conducted in this study for the case of private households in Germany. - Highlights: ► A macroeconomic model to assess outage cost is proposed. ► Possibilities for substitution are considered by analyzing individual preferences for the time-use. ► Uncertainties are taken into account by using a Monte Carlo simulation. ► This study reveals the distribution of outage costs to different electricity consumers. ► Implications for energy policy decisions are discussed.

  18. Does it matter when a power outage occurs? - A choice experiment study on the willingness to pay to avoid power outages

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Fredrik; Martinsson, Peter [Department of Economics, Goeteborg University, Box 640, 405, 30 Goeteborg (Sweden)

    2008-05-15

    Using a choice experiment survey, the marginal willingness to pay (WTP) among Swedish households for reductions in power outages is estimated. The results from the random parameter logit estimation indicate that the marginal WTP increases with the duration of the outages, and is higher if the outages occur during weekends and during winter months. Moreover, the random parameter logit model allows us to estimate a sample distribution of WTP and we find a significant unobserved heterogeneity in some of the outage attributes. Given that households have negative welfare effects from outages, it is important that policy makers consider these negative impacts on household utility when regulating the Swedish electricity market. (author)

  19. Does it matter when a power outage occurs? - A choice experiment study on the willingness to pay to avoid power outages

    International Nuclear Information System (INIS)

    Using a choice experiment survey, the marginal willingness to pay (WTP) among Swedish households for reductions in power outages is estimated. The results from the random parameter logit estimation indicate that the marginal WTP increases with the duration of the outages, and is higher if the outages occur during weekends and during winter months. Moreover, the random parameter logit model allows us to estimate a sample distribution of WTP and we find a significant unobserved heterogeneity in some of the outage attributes. Given that households have negative welfare effects from outages, it is important that policy makers consider these negative impacts on household utility when regulating the Swedish electricity market. (author)

  20. Impacts of organization and management on outage performance

    International Nuclear Information System (INIS)

    From probabilistic safety assessments and root cause analyses for incidents/accidents, the risk at refueling outage has recently been recognized to be comparable to (or even more significant than) the commonly evaluated risk at power in a Nuclear Power Plant (NPP). This paper summarizes the major findings in the aspect of 'organization and management', which is identified to have significant impacts on outage performance in the qualitative assessment of a PWR plant. In order to reduce the potential risk arisen from those identified imperfections, the corresponding suggestions are also proposed. (author)

  1. Constitutive Modeling and Numerical Simulation of Frp Confined Concrete Specimens

    Science.gov (United States)

    Smitha, Gopinath; Ramachandramurthy, Avadhanam; Nagesh, Ranganatha Iyer; Shahulhameed, Eduvammal Kunhimoideen

    2014-09-01

    Fiber-reinforced polymer (FRP) composites are generally used for the seismic retrofit of concrete members to enhance their strength and ductility. In the present work, the confining effect of Carbon Fiber-Reinforced Polymer (CFRP) composite layers has been investigated by numerical simulation. The numerical simulation has been carried out using nonlinear finite element analysis (FEA) to predict the response behaviour of CFRP-wrapped concrete cylinders. The nonlinear behaviour of concrete in compression and the linear elastic behaviour of CFRP has been modeled using an appropriate constitutive relationship. A cohesive model has been developed for modeling the interface between the concrete and CFRP. The interaction and damage failure criteria between the concrete to the cohesive element and the cohesive element to the CFRP has also been accounted for in the modeling. The response behaviour of the wrapped concrete specimen has been compared with the proposed interface model and with a perfectly bonded condition. The results obtained from the present study showed good agreement with the experimental load-displacement response and the failure pattern in the literature. Further, a sensitivity analysis has been carried out to study the effect of the number of layers of CFRP on the concrete specimens. It has been observed that wrapping with two layers was found to be the optimum, beyond which the response becomes flexible but with a higher load-carrying capacity

  2. Integrated use of Primavera and ORAM codes in outage 1999 at NPP Krsko

    International Nuclear Information System (INIS)

    The paper deals with the following postulated main goals of outage scheduling with Primavera tool at Krsko NPP: planning and controlling of resources (people, equipment, locations, sources), controlling the safety aspects of an outage and assuring defense-in-depth philosophy (through integrated safety assessment by ORAM code), diversity use of the plan during preparations period and outage progress (MCB, work leaders, management, planning Dept., subcontractors, support, etc.), allowing for optimization of outage duration. A snapshot in Primavera of what actually happened in outage 1999, lessons learned and a new work template is the scope of the next year outage.(author)

  3. Design and behavior of reinforced concrete beams strengthened with fiber-reinforced plastics (FRP)

    Science.gov (United States)

    El-Mihilmy, Mahmoud Tharwat

    A comprehensive investigation of the design and behavior of reinforced concrete beams strengthened with externally bonded FRP laminates has been conducted. The study has confirmed the applicability of the strain compatibility method for calculating the increased ultimate moment capacity of the repaired beams. An upper limit to the amount of FRP that can be added to a specific structure was recommended to ensure ductile behavior. Design charts to facilitate calculations of the ultimate moment capacity for reinforced concrete beams strengthened with FRP laminates were developed. The results of a subsequent parametric investigation indicate that strengthening reinforced concrete beams with FRP laminates can enhance their ultimate capacity by as much as three times the original strength, especially for beams with a low steel ratio. It was also determined that, increasing the concrete compressive strength and the FRP modulus of elasticity increases the beam ultimate flexural capacity significantly; however, the repaired beams are less ductile than the pre-repaired concrete beams. During the course of the study, it had been noticed that the current ACI recommended method for calculating deflections for ordinary reinforced concrete beams does not render an accurate estimate for reinforced concrete beams strengthened with FRP laminates. A simplified equation for predicting the deflection of reinforced concrete beams repaired with FRP was developed and verified with comparisons to experimental results. The effectiveness of strengthening an existing bridge with externally bonded FRP laminates was investigated through comprehensive static and dynamic finite element analyses. The results of these analyses correlate well with field load test results. The repaired girders exhibited an average reduction in reinforcing steel stresses of 11 percent and an average reduction in midspan girder deflections of 9 percent. The results of the study also indicated that existing methods for

  4. Identification of intermediate debonding damage in FRP-plated RC beams based on multi-objective particle swarm optimization without updated baseline model

    OpenAIRE

    Perera Velamazán, Ricardo; Sevillano Bravo, Enrique; Diego Villalón, Ana de; Arteaga Iriarte, Ángel

    2014-01-01

    Fiber reinforced polymer composites (FRP) have found widespread usage in the repair and strengthening of concrete structures. FRP composites exhibit high strength-to-weight ratio, corrosion resistance, and are convenient to use in repair applications. Externally bonded FRP flexural strengthening of concrete beams is the most extended application of this technique. A common cause of failure in such members is associated with intermediate crack-induced debonding (IC debonding) of the FRP substr...

  5. Distributed Long-Gauge Optical Fiber Sensors Based Self-Sensing FRP Bar for Concrete Structure

    Science.gov (United States)

    Tang, Yongsheng; Wu, Zhishen

    2016-01-01

    Brillouin scattering-based distributed optical fiber (OF) sensing technique presents advantages for concrete structure monitoring. However, the existence of spatial resolution greatly decreases strain measurement accuracy especially around cracks. Meanwhile, the brittle feature of OF also hinders its further application. In this paper, the distributed OF sensor was firstly proposed as long-gauge sensor to improve strain measurement accuracy. Then, a new type of self-sensing fiber reinforced polymer (FRP) bar was developed by embedding the packaged long-gauge OF sensors into FRP bar, followed by experimental studies on strain sensing, temperature sensing and basic mechanical properties. The results confirmed the superior strain sensing properties, namely satisfied accuracy, repeatability and linearity, as well as excellent mechanical performance. At the same time, the temperature sensing property was not influenced by the long-gauge package, making temperature compensation easy. Furthermore, the bonding performance between self-sensing FRP bar and concrete was investigated to study its influence on the sensing. Lastly, the sensing performance was further verified with static experiments of concrete beam reinforced with the proposed self-sensing FRP bar. Therefore, the self-sensing FRP bar has potential applications for long-term structural health monitoring (SHM) as embedded sensors as well as reinforcing materials for concrete structures. PMID:26927110

  6. Secreted Frizzled related protein-4 (sFRP4) promotes epidermal differentiation and apoptosis

    International Nuclear Information System (INIS)

    The skin provides vital protection from infection and dehydration. Maintenance of the skin is through a constant program of proliferation, differentiation and apoptosis of epidermal cells, whereby proliferating cells in the basal layer differentiating to form the keratinized, anucleated stratum corneum. The WNT signalling pathway is known to be important in the skin. WNT signalling has been shown to be important both in epidermal development and in the maintenance and cycling of hair follicles and epidermal stem cells. However, the precise role for this pathway in epidermal differentiation remains unknown. We investigated the role of the WNT signalling inhibitor sFRP4 in epidermal differentiation. sFRP4 is expressed in both normal skin and keratinocytes in culture. Expression of sFRP4 mRNA and protein increases with keratinocyte differentiation and apoptosis, whilst exposure of keratinocytes to exogenous sFRP4 promotes apoptosis and expression of the terminal differentiation marker Involucrin. These data suggest sFRP4 promotes epidermal differentiation.

  7. An investigation into the impact of cryogenic environment on mechanical stresses in FRP composites

    Science.gov (United States)

    Fifo, O.; Basu, B.

    2015-07-01

    Fibre reinforced polymer (FRP) composites are fast becoming a highly utilised engineering material for high performance applications due to their light weight and high strength. Carbon fibre and other high strength fibres are commonly used in design of aerospace structures, wind turbine blades, etc. and potentially for propellant tanks of launch vehicles. For the aforementioned fields of application, stability of the material is essential over a wide range of temperature particularly for structures in hostile environments. Many studies have been conducted, experimentally, over the last decade to investigate the mechanical behaviour of FRP materials at varying subzero temperature. Likewise, tests on aging and cycling effect (room to low temperature) on the mechanical response of FRP have been reported. However, a relatively lesser focused area has been the mechanical behaviour of FRP composites under cryogenic environment. This article reports a finite element method of investigating the changes in the mechanical characteristics of an FRP material when temperature based analysis falls below zero. The simulated tests are carried out using a finite element package with close material properties used in the cited literatures. Tensile test was conducted and the results indicate that the mechanical responses agree with those reported in the literature sited.

  8. Seismic response of concrete gravity dam reinforced with FRP sheets on dam surface

    Directory of Open Access Journals (Sweden)

    Hong ZHONG

    2013-10-01

    Full Text Available This paper aims at exploring the effects of anti-seismic reinforcement with the fiber-reinforced polymer (FRP material bonded to the dam surface in dam engineering. Time-history analysis was performed to simulate the seismic failure process of a gravity dam that was assumed to be reinforced at the locations of slope discontinuity at the downstream surface, part of the upstream face, and the dam heel. A damage model considering the influence of concrete heterogeneity was used to model the nonlinearity of concrete. A bond-slip model was applied to the interface between FRP and concrete, and the reinforcement mechanism was analyzed through the bond stress and the stress in FRP. The results of the crack pattern, displacement, and acceleration of the reinforced dam were compared with those of the original one. It is shown that FRP, as a reinforcement material, postpones the occurrence of cracks and slows the crack propagation, and that cracks emanating from the upstream surface and downstream surface are not connected, meaning that the reinforced dam can retain water-impounding function when subjected to the earthquake. Anti-seismic reinforcement with FRP is therefore beneficial to improving the seismic resistant capability of concrete dams.

  9. Distributed Long-Gauge Optical Fiber Sensors Based Self-Sensing FRP Bar for Concrete Structure.

    Science.gov (United States)

    Tang, Yongsheng; Wu, Zhishen

    2016-01-01

    Brillouin scattering-based distributed optical fiber (OF) sensing technique presents advantages for concrete structure monitoring. However, the existence of spatial resolution greatly decreases strain measurement accuracy especially around cracks. Meanwhile, the brittle feature of OF also hinders its further application. In this paper, the distributed OF sensor was firstly proposed as long-gauge sensor to improve strain measurement accuracy. Then, a new type of self-sensing fiber reinforced polymer (FRP) bar was developed by embedding the packaged long-gauge OF sensors into FRP bar, followed by experimental studies on strain sensing, temperature sensing and basic mechanical properties. The results confirmed the superior strain sensing properties, namely satisfied accuracy, repeatability and linearity, as well as excellent mechanical performance. At the same time, the temperature sensing property was not influenced by the long-gauge package, making temperature compensation easy. Furthermore, the bonding performance between self-sensing FRP bar and concrete was investigated to study its influence on the sensing. Lastly, the sensing performance was further verified with static experiments of concrete beam reinforced with the proposed self-sensing FRP bar. Therefore, the self-sensing FRP bar has potential applications for long-term structural health monitoring (SHM) as embedded sensors as well as reinforcing materials for concrete structures. PMID:26927110

  10. Load-induced debonding of FRP composites applied to reinforced concrete

    Science.gov (United States)

    Blok, Joel; Brown, Jeff

    2009-05-01

    Fiber-reinforced polymer (FRP) composites are widely used to increase the flexural and shear capacity of reinforced concrete (RC) elements. One potential disadvantage is that strengthened surfaces are no longer visible and cracks or delaminations that result from excessive loading or fatigue may go undetected. This research investigated thermal imaging techniques for monitoring and evaluating load-induced delamination of FRP composites applied to small scale RC beams. Two beams (3.5 in x 4.5 in x 58 in) were loaded monotonically to failure. Infrared thermography (IRT) inspections were performed at various load levels through failure using a composite phase imaging technique. Two similar beams were tested in fatigue and periodic IRT inspections were performed at 50,000-cycle intervals. Individual phase values for each pixel were designated as "well-bonded", "suspect" or "unbonded" to indicate the quality of FRP bond. Suspect areas included regions of excess thickened-epoxy tack-coat and smaller installation defects in the unloaded specimens. The long-term objective of this research is to develop a practical framework for conducting quantitative IRT inspections of FRP composites applied to RC and incorporating these results into acceptance criteria for new installations and predictions for the remaining service life of in-service FRP systems. This method may also offer insight into the necessity for repairs to in-service systems.

  11. Options for shortening nuclear power plant refueling outages

    International Nuclear Information System (INIS)

    Deregulation of the European electricity market on 01.01.1999 forced a large number of electric utilities- especially nuclear power plant operators - to find ways of drastically cutting down their costs in order to be able to compete successfully within the new market environment. Nuclear power plants currently in operation mainly have three potential ways of reducing their power generating costs: by increasing plant availability, reducing fuel costs and cutting down operating costs. The optimization of plant refueling outages offers considerable potential for enhancing plant availability, but also helps bring down operating costs by reducing expenditure on maintenance. In order to optimize an outage in terms of its duration and costs, a variety of approaches are possible - all of which, however, involve certain key factors such as good organization, planning, logistics and control, improvement of equipment and tools, as well as motivation of personnel. Another aspect is the introduction of innovative technologies. In the last few years, such technologies have frequently enabled maintenance effort to be reduced, thus saving considerable time, and have also resulted in a need for fewer personnel to carry out the work, thus reducing radiation exposure. In many instances they have also improved the quality of work and outage performance as a whole. The paper uses recent examples to show how innovative technologies can contribute to-wards reducing nuclear plant maintenance costs and shorten the duration of refueling out-ages. (author)

  12. Outage planning: basics are the key to success

    International Nuclear Information System (INIS)

    Northeast Utilities Service Company (NUSCO) services approx.1,126,000 customers in Connecticut and western Massachusetts. The company's operating nuclear facilities include Connecticut Yankee, Millstone Unit 1, and Millstone Unit 2. Although NUSCO's earliest commercial operation of a nuclear plant dates back to January 1968, the cost and scheduling section was not created until 1979. The section was created as a corporate service organization composed of four major units: cost engineering, estimating, backfit/betterment planning, and outage planning. To date, 12 of the 28 nuclear refueling outages have been planned and scheduled by the department. There is now a wealth of outage information available from both company personnel and a historical computer database. Current directions within cost and scheduling have been back to basics. The backfit/betterment planning unit has been working with the in-house engineering and design groups to define their work scopes better, to develop a generic work breakdown structure, and to provide better resource planning. The estimating and cost engineering units are working to utilize this to provide true cost and schedule integration. Outage planning will wait for these developments on projects before discussing possible applications in the field

  13. Practice of fuel management and outage strategy at Paks NPP

    International Nuclear Information System (INIS)

    The Paks Nuclear Power Plant generates almost 40% of Hungarian electricity production at lowest price. In spite of this fact the reduction of operational and maintenance costs is one of the most important goal of the plant management. The proper fuel management and outage strategy can give a considerable influence for this cost reduction. The aim of loading pattern planning is to get the required cycle length with available fuel cassettes and to keep all key parameters of safety analysis under safety limits. Another important point is production at profit, where both the fuel and spent fuel cost are determining. Earlier the conditions given by our only fuel supplier restricted our possibilities, so at the beginning the fuel arrangement changing was the only way to improve efficiency of fuel using. As first step we introduced the low leakage core design. The next step was the 4 years cycle using of some cassettes. By this way nearly half of 3 years cycle old cassettes remained in the core for fourth cycle. In the immediate future we want to use profiled cassettes developed by Russian supplier. Simultaneously we will load new type of WWER cassettes with burnable poison developed by BNFL Company. Hereby we can apply more BNFL cassettes for four years cycle even more. Both cost of fuel and number of spent fuel can be reduced besides keeping parameters under safety limits. The Hungarian in service inspection rules determine that every four year we have to make a complete inspection of reactor vessel. Therefore earlier we had two types of outages. Every 4 years we planned a long outage with 55-65 days duration and normal ones with about 30-35 days duration between the long ones. During the normal outages this way did not give us enough room to utilise the shortest possible critical path determined by works on reactor. Some years ago we changed our outage strategy. Now we plan every 4 years a long outage, and between them one normal and two short ones. As a result the

  14. Crack-induced debonding failure in fiber reinforced plastics (FRP) strengthened concrete beams: Experimental and theoretical analysis

    Science.gov (United States)

    Pan, Jinlong

    External bonding of FRP plates to the tension substrate of RC beams has been accepted as an efficient and effective technique for flexural strengthening. In this thesis, different problems related to crack-induced debonding of the FRP plate in the flexural strengthened concrete beams have been investigated. FRP strengthened RC beam may fail by FRP debonding from the bottom of a major flexural crack in the span. This kind of failure is studied with the direct shear test in the present research work. Our experimental investigation focuses on the effect of concrete composition on the bond behavior between FRP and concrete. Based on the test results, the bond capacity of the specimen is found to be governed by the concrete surface tensile strength, aggregate size and aggregate content. Then, the neural network is employed to derive an empirical expression for the interfacial fracture energy in terms of concrete surface tensile strength and aggregate content. Using the empirical equation, simulated bond capacity is in good agreement with experimental results. In the FRP strengthened RC beams, debonding of the FRP plate often occurs under the presence of multiple cracks along the span. In the present thesis, experimental and theoretical investigations are performed to study the effect of multiple secondary cracks on the debonding behavior and ultimate load capacity. A new analytical model for FRP debonding under multiple cracks has been developed. The effect of the multiple secondary cracks on the shear softening in the debonded zone is explicitly considered in the model. Using the new model, the simulated values of ultimate load when debonding occurs are in good agreement with measured values. In the FRP strengthened RC beams, concrete cover separation or plate end debonding can be avoided by applying tapers at the FRP plate end. In this situation, it is easier for FRP debonding to be induced by a major flexural crack close to the support. To study the effect of the

  15. World class performance: the outage/operating cycle continuum

    International Nuclear Information System (INIS)

    It's all about Performance! Predictable and sustainable high performance is the key to public and stakeholder confidence in the nuclear industry. Why? Because nuclear is unique and safe, reliable operation each and every day is required to keep public trust. What better way to demonstrate this predictability than in breaker to breaker operating runs? Delivering on what was promised is the essence of our OPG accountability model: 'Say it, Do it'. This presentation is drawn from practical experience gained during the most recent planned maintenance outages at Darlington Nuclear. Key elements for outage success that will be discussed include; Human Performance: Ensuring each action is deliberate and executed right the first time; Continuous Learning: Recent examples demonstrating how drawing from lessons learned and operating experience worldwide can dramatically improve outage performance; Teamwork and Partnership: Recognizing our industry is too complex for a single; individual or organization to run on its own; Scope Selection: Darlington currently has an industry leading 0.5% Forced Loss Rate (FLR). If right work is selected and executed at the right time then ultimately the plant speaks and it shows up in low FLR and high Nuclear Performance Index; Planning: Ask and anticipate what can go wrong, what options exist and then pre-decide what path you would take. Some practical tools will be provided which have been recently used to plan out surprises; Oversight: An outage left to run its own course will have a surprise outcome. Strong management oversight is required to meet the goals of outage execution. Tips on how to improve communication and accountability will be discussed. Trust is built on confidence and confidence is built on sustainable performance. World class sustainable performance requires using all the tools available. This discussion will provide insight on these very tools. (author)

  16. Constitutive Behavior and Finite Element Analysis of FRP Composite and Concrete Members

    Directory of Open Access Journals (Sweden)

    Ki Yong Ann

    2013-09-01

    Full Text Available The present study concerns compressive and flexural constitutive models incorporated into an isoparametric beam finite element scheme for fiber reinforced polymer (FRP and concrete composites, using their multi-axial constitutive behavior. The constitutive behavior of concrete was treated in triaxial stress states as an orthotropic hypoelasticity-based formulation to determine the confinement effect of concrete from a three-dimensional failure surface in triaxial stress states. The constitutive behavior of the FRP composite was formulated from the two-dimensional classical lamination theory. To predict the flexural behavior of circular cross-section with FRP sheet and concrete composite, a layered discretization of cross-sections was incorporated into nonlinear isoparametric beam finite elements. The predicted constitutive behavior was validated by a comparison to available experimental results in the compressive and flexural beam loading test.

  17. Large Current Lightning Mimic Test for FRP Blades of Wind Turbine Generators

    Science.gov (United States)

    Hanai, Masahiro; Ikeda, Hisatoshi; Nakadate, Masumi; Sakamoto, Haruo

    In Japan, lightning damage to FRP blades of wind turbine generators has been increasing in parallel with the recent increase in the installation of wind turbine generators. Therefore, we established a test method, while clarifying the destructive climate of lightning, and examined a method of preventing destruction. A high-voltage test clearly showed that lightning easily penetrates FRP that is not processed to be conductive. Moreover, after developing a test method, an examination with a large current successfully reproduced blade damage, and revealed the failure mechanism, which explains breakdowns of actual machines. If lightning penetrates a FRP blade, the air temperature inside the blade rises. As a result, pressure increases and the blade is damaged. Moreover, the breakdown of positive polarity (winter) lightning can be examined with a large current that is generated by a short circuit generator.

  18. Non-linear heterogeneous FE approach for FRP strengthened masonry arches

    Science.gov (United States)

    Bertolesi, Elisa; Milani, Gabriele; Fedele, Roberto

    2015-12-01

    A fast and reliable non-linear heterogeneous FE approach specifically conceived for the analysis of FRP-reinforced masonry arches is presented. The approach proposed relies into the reduction of mortar joints to interfaces exhibiting a non-linear holonomic behavior, with a discretization of bricks by means of four-noded elastic elements. The FRP reinforcement is modeled by means of truss elements with elastic-brittle behavior, where the peak tensile strength is estimated by means of a consolidated approach provided by the Italian guidelines CNR-DT200 on masonry strengthening with fiber materials, where the delamination of the strip from the support is taken into account. The model is validated against some recent experimental results relying into circular masonry arches reinforced at both the intrados and the extrados. Some sensitivity analyses are conducted varying the peak tensile strength of the trusses representing the FRP reinforcement.

  19. Dynamic response of RC beams strengthened with near surface mounted Carbon-FRP rods subjected to damage

    Science.gov (United States)

    Capozucca, R.; Blasi, M. G.; Corina, V.

    2015-07-01

    Near surface mounted (NSM) technique with fiber reinforced polymer (FRP) is becoming a common method in the strengthening of concrete beams. The availability of NSM FRP technique depends on many factors linked to materials and geometry - dimensions of the rods used, type of FRP material employed, rods’ surface configuration, groove size - and to adhesion between concrete and FRP rods. In this paper detection of damage is investigated measuring the natural frequency values of beam in the case of free-free ends. Damage was due both to reduction of adhesion between concrete and carbon-FRP rectangular and circular rods and cracking of concrete under static bending tests on beams. Comparison between experimental and theoretical frequency values evaluating frequency changes due to damage permits to monitor actual behaviour of RC beams strengthened by NSM CFRP rods.

  20. ALARA database value in future outage work planning and dose management

    International Nuclear Information System (INIS)

    ALARA database encompassing job-specific duration and man-rem plant specific information over three refueling outages represents an invaluable tool for the outage work planner and ALARA engineer. This paper describes dose-management trends emerging based on analysis of three refueling outages at Clinton Power Station. Conclusions reached based on hard data available from a relational database dose-tracking system is a valuable tool for planning of future outage work. The system's ability to identify key problem areas during a refueling outage is improving as more outage comparative data becomes available. Trends over a three outage period are identified in this paper in the categories of number and type of radiation work permits implemented, duration of jobs, projected vs. actual dose rates in work areas, and accuracy of outage person-rem projection. The value of the database in projecting 1 and 5 year station person-rem estimates is discussed

  1. Secreted Frizzled-related protein-2 (sFRP2) augments canonical Wnt3a-induced signaling

    Energy Technology Data Exchange (ETDEWEB)

    Marschall, Zofia von [Craniofacial and Skeletal Diseases Branch, NIDCR, NIH, DHHS, Bethesda, MD (United States); Fisher, Larry W., E-mail: lfisher@dir.nidcr.nih.gov [Craniofacial and Skeletal Diseases Branch, NIDCR, NIH, DHHS, Bethesda, MD (United States)

    2010-09-24

    Research highlights: {yields} sFRP2 enhances the Wnt3a-induced {beta}-catenin stabilization and its nuclear translocation. {yields} sFRP2 enhances LRP6 phosphorylation and Wnt3a/{beta}-catenin transcriptional reporter activity. {yields} Dickkopf-1 (DKK1) fully antagonizes both Wnt3a/sFRP2-induced LRP6 phosphorylation and transcriptional activity. {yields} sFRP2 enhances expression of genes known to be regulated by Wnt3a signaling. -- Abstract: Secreted Frizzled-related proteins (sFRP) are involved in embryonic development as well as pathological conditions including bone and myocardial disorders and cancer. Because of their sequence homology with the Wnt-binding domain of Frizzled, they have generally been considered antagonists of canonical Wnt signaling. However, additional activities of various sFRPs including both synergism and mimicry of Wnt signaling as well as functions other than modulation of Wnt signaling have been reported. Using human embryonic kidney cells (HEK293A), we found that sFRP2 enhanced Wnt3a-dependent phosphorylation of LRP6 as well as both cytosolic {beta}-catenin levels and its nuclear translocation. While addition of recombinant sFRP2 had no activity by itself, Top/Fop luciferase reporter assays showed a dose-dependent increase of Wnt3a-mediated transcriptional activity. sFRP2 enhancement of Wnt3a signaling was abolished by treatment with the Wnt antagonist, Dickkopf-1 (DKK1). Wnt-signaling pathway qPCR arrays showed that sFRP2 enhanced the Wnt3a-mediated transcriptional up-regulation of several genes regulated by Wnt3a including its antagonists, DKK1, and Naked cuticle-1 homolog (NKD1). These results support sFRP2's role as an enhancer of Wnt/{beta}-catenin signaling, a result with biological impact for both normal development and diverse pathologies such as tumorigenesis.

  2. A framework and review of customer outage costs: Integration and analysis of electric utility outage cost surveys

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, Leora; Sullivan, Michael; Van Liere, Kent; Katz, Aaron; Eto, Joseph

    2003-11-01

    A clear understanding of the monetary value that customers place on reliability and the factors that give rise to higher and lower values is an essential tool in determining investment in the grid. The recent National Transmission Grid Study recognizes the need for this information as one of growing importance for both public and private decision makers. In response, the U.S. Department of Energy has undertaken this study, as a first step toward addressing the current absence of consistent data needed to support better estimates of the economic value of electricity reliability. Twenty-four studies, conducted by eight electric utilities between 1989 and 2002 representing residential and commercial/industrial (small, medium and large) customer groups, were chosen for analysis. The studies cover virtually all of the Southeast, most of the western United States, including California, rural Washington and Oregon, and the Midwest south and east of Chicago. All variables were standardized to a consistent metric and dollar amounts were adjusted to the 2002 CPI. The data were then incorporated into a meta-database in which each outage scenario (e.g., the lost of electric service for one hour on a weekday summer afternoon) is treated as an independent case or record both to permit comparisons between outage characteristics and to increase the statistical power of analysis results. Unadjusted average outage costs and Tobit models that estimate customer damage functions are presented. The customer damage functions express customer outage costs for a given outage scenario and customer class as a function of location, time of day, consumption, and business type. One can use the damage functions to calculate outage costs for specific customer types. For example, using the customer damage functions, the cost experienced by an ''average'' customer resulting from a 1 hour summer afternoon outage is estimated to be approximately $3 for a residential customer, $1

  3. A simplified spectral approachfor impedance-based damage identification of frp-strengthened rc beams

    OpenAIRE

    Sun, Rui

    2015-01-01

    Hoy en día, el refuerzo y reparación de estructuras de hormigón armado mediante el pegado de bandas de polímeros reforzados con fibras (FRP) se emplea cada vez con más frecuencia a causa de sus numerosas ventajas. Sin embargo, las vigas reforzadas con esta técnica pueden experimentar un modo de fallo frágil a causa del despegue repentino de la banda de FRP a partir de una fisura intermedia. A pesar de su importancia, el número de trabajos que abordan el estudio de este mecanismo de fallo y su...

  4. LIDAR AND INS FUSION IN PERIODS OF GPS OUTAGES FOR MOBILE LASER SCANNING MAPPING SYSTEMS

    Directory of Open Access Journals (Sweden)

    I. Klein

    2012-09-01

    Full Text Available Mobile laser scanning systems are becoming an increasingly popular means to obtain 3D coverage on a large scale. To perform the mapping, the exact position of the vehicle must be known throughout the trajectory. Exact position is achieved via integration of Global Positioning Systems (GPS and Inertial Navigation Systems (INS. Yet, in urban environments, cases of complete or even partial GPS outages may occur leaving the navigation solution to rely only on the INS. The INS navigation solution degrades with time as the Inertial Measurement Unit (IMU measurements contains noise, which permeates into the navigation equations. Degradation of the position determination leads to loss of data in such segments. To circumvent such drift and its effects, we propose fusing INS with lidar data by using building edges. This detection of edges is then translated into position data, which is used as an aiding to the INS. It thereby enables the determination of the vehicle position with a satisfactory level accuracy, sufficient to perform the laser-scanning based mapping in those outage periods.

  5. Analysis of heterogeneous boron dilution transients during outages with APROS 3D nodal core model

    International Nuclear Information System (INIS)

    A diluted water plug can form inside the primary coolant circuit if the coolant flow has stopped at least temporarily. The source of the clean water can be external or the fresh water can build up internally during boiling/condensing heat transfer mode, which can occur if the primary coolant inventory has decreased enough during an accident. If the flow restarts in the stagnant primary loop, the diluted water plug can enter the reactor core. During outages after the fresh fuel has been loaded and the temperature of the coolant is low, the dilution potential is the highest because the critical boron concentration is at the maximum. This paper examines the behaviour of the core as clean or diluted water plugs of different sizes enter the core during outages. The analysis were performed with the APROS 3D nodal core model of Loviisa VVER-440, which contains an own flow channel and 10 axial nodes for each fuel assembly. The widerange cross section data was calculated with CASMO-4E. According to the results, the core can withstand even large pure water plugs without fuel failures on natural circulation. The analyses emphasize the importance of the simulation of the backflows inside the core when the reactor is on natural circulation.

  6. Development and demonstration of techniques for reducing occupational radiation doses during refueling outages. Tasks 7A/7B. Advanced outage management and radiation exposure control

    International Nuclear Information System (INIS)

    Objectives of Tasks 7A and 7B were to develop and demonstrate computer based systems to assist plant management and staff in utilizing information more effectively to reduce occupational exposures received as a result of refueling outages, and to shorten the duration of the outage. The Advanced Outage Management (AOM) Tool (Task 7A) is an automated outage planning system specifically designed to meet the needs of nuclear plant outage management. The primary objective of the AOM tool is to provide a computerized system that can manipulate the information typically associated with outage planning and scheduling to furnish reports and schedules that more accurately project the future course of the outage. The Radiation Exposure Control (REC) Tool (Task 7B) is a computerized personnel radiation exposure accounting and management system designed to enable nuclear plant management to project and monitor total personnel radiation exposure on a real-time basis. The two systems were designed to operate on the same computer system and interface through a common database that enables information sharing between plant organizations not typically interfaced. This interfacing provides outage planners with a means of incorporating occupational radiation exposure as a factor for making decisions on the course of an outage

  7. Outage analysis of opportunistic decode-and-forward relaying

    KAUST Repository

    Tourki, Kamel

    2010-09-01

    In this paper, we investigate a dual-hop opportunistic decode-and-forward relaying scheme where the source may or not be able to communicate directly with the destination. We first derive statistics based on exact probability density function (PDF) of each hop. Then, the PDFs are used to determine closed-form outage probability expression for a transmission rate R. Furthermore, we evaluate the asymptotic outage performance and the diversity order is deduced. Unlike existing works where the analysis focused on high signal-to-noise ratio (SNR) regime, such results are important to enable the designers to take decisions regarding practical systems that operate at low SNR regime. We show that performance simulation results coincide with our analytical results under practical assumption of unbalanced hops. © 2010 IEEE.

  8. Outage Constrained Secrecy Rate Maximization Using Cooperative Jamming

    CERN Document Server

    Luo, Shuangyu; Petropulu, Athina

    2012-01-01

    We consider a Gaussian MISO wiretap channel, where a multi-antenna source communicates with a single-antenna destination in the presence of a single-antenna eavesdropper. The communication is assisted by multi-antenna helpers that act as jammers to the eavesdropper. Each helper independently transmits noise which lies in the null space of the channel to the destination, thus creates no interference to the destination. Under the assumption that there is eavesdropper channel uncertainty, we derive the optimal covariance matrix for the source signal so that the secrecy rate is maximized subject to probability of outage and power constraints. Assuming that the eavesdropper channels follow zero-mean Gaussian model with known covariances, we derive the outage probability in a closed form. Simulation results in support of the analysis are provided.

  9. Ontario-U.S. power outages : impacts on critical infrastructure

    International Nuclear Information System (INIS)

    This paper described the power outage and resulting blackout that occurred on August 14, 2003 and identified how critical infrastructure was directly and interdependently impacted in Canada. The aim of the paper was to assist critical infrastructure protection and emergency management professionals in assessing the potential impacts of large-scale critical infrastructure disruptions. Information for the study was acquired from Canadian and American media reports and cross-sectoral information sharing with provincial and federal governments and the private sector. The blackout impacted most of the sources and means of generating, transmitting and distributing power within the area, which in turn impacted all critical infrastructure sectors. Landline and cellular companies experienced operational difficulties, which meant that emergency responders were impacted. Newspapers and the electronic media struggled to release information to the public. The banking and finance industry experienced an immediate degradation of services. The power outage caused shipping and storage difficulties for commercial retailers and dairy producers. A number of incidents were reported where only partially treated waste water was released into neighbouring waterways. The timing of the blackout coincided with the closures of workplaces and created additional difficulties on transportation networks. Many gas station pumps were inoperable. Police, fire departments and ambulance services experienced a dramatic increase in the volume of calls received, and all branches of the emergency services sector encountered transportation delays and difficulties with communications equipment. Nuclear reactors were also impacted. An estimated 150,000 Government of Canada employees were unable to report to work. Estimates have indicated that the power outage cost Ontario's economy between $1 and $2 billion. The outage negatively impacted 82 per cent of small businesses in Ontario. 170 refs., 3 figs

  10. Outage probability of distributed beamforming with co-channel interference

    KAUST Repository

    Yang, Liang

    2012-03-01

    In this letter, we consider a distributed beamforming scheme (DBF) in the presence of equal-power co-channel interferers for both amplify-and-forward and decode-and-forward relaying protocols over Rayleigh fading channels. We first derive outage probability expressions for the DBF systems. We then present a performance analysis for a scheme relying on source selection. Numerical results are finally presented to verify our analysis. © 2011 IEEE.

  11. Effect of Shear Resistance on Flexural Debonding Load-Carrying Capacity of RC Beams Strengthened with Externally Bonded FRP Composites

    Directory of Open Access Journals (Sweden)

    Guibing Li

    2014-05-01

    Full Text Available Debonding failure is the main failure mode in flexurally strengthened reinforced concrete beams by externally bonded or near surface mounted fibre reinforced polymer (FRP composites. It is believed that FRP debonding will be initiated if the shear stress on the concrete-FRP interface reaches the tensile strength of concrete. However, it was found through experimental and analytical studies that the debonding mechanism of FRP composites has the potential of shear failure in combination with debonding failure. Moreover, the shear failure probably influences the debonding failure. Presently, there are very little experimental and analytical studies to investigate the influence of shear resistance of reinforced concrete (RC beam on FRP debonding failure. The current study investigates and analyzes the effect of shear resistance on FRP debonding failure based on test results. The analytical results show that the shear resistance of RC beam has a great effect on flexural debonding load-carrying capacity of FRP-strengthened RC beam. The influence of shear resistance on flexural debonding load-carrying capacity must be fully considered in flexural strengthening design of RC beams.

  12. Downregulation of sFRP-2 by epigenetic silencing activates the β-catenin/Wnt signaling pathway in esophageal basaloid squamous cell carcinoma.

    Science.gov (United States)

    Saito, Tsuyoshi; Mitomi, Hiroyuki; Imamhasan, Abdukadir; Hayashi, Takuo; Mitani, Keiko; Takahashi, Michiko; Kajiyama, Yoshiaki; Yao, Takashi

    2014-02-01

    Basaloid squamous cell carcinoma (BSCC) of the esophagus is a rare variant of typical squamous cell carcinoma (SCC) associated with poor survival. A characteristic feature is nuclear accumulation of β-catenin, without a mutation of the gene. We studied the methylation status of Wnt antagonist genes, such as secreted frizzled-related protein (sFRP) gene family members, Wnt inhibitory factor-1 (WIF-1), Dickkopf-1 (Dkk-1), and human Dapper protein-1 (HDPR-1), and alterations of the APC, Axin1, and Axin2 genes in 30 cases of esophageal BSCC. β-catenin and sFRP (sFRP-1, sFRP-2, sFRP-4, sFRP-5) protein expression was examined by immunohistochemistry. APC, Axin1, and Axin2 gene mutations were detected in 3, 2, and 2 cases, respectively, and 6 cases (20 %) harbored at least 1 alteration in these genes. Methylation of the sFRP-2 promoter region was observed in all cases, and methylation was frequent in sFRP-1 and sFRP-5, but infrequent in Dkk-1, WIF-1, sFRP-4, and HDPR-1. sFRP-2 expression was almost completely absent in 25 cases (83 %), consistent with the methylation status. Nuclear accumulation of β-catenin was observed in all cases. sFRP-5 expression was associated with a low nuclear β-catenin labeling index. These results show that sFRP-2 is a target gene of hypermethylation in esophageal BSCC and suggest that sFRP-2 might contribute to BSCC tumorigenesis through the Wnt/β-catenin signaling pathway. PMID:24464051

  13. Upgrading BWR training simulators for annual outage operation training

    International Nuclear Information System (INIS)

    Based upon the recently developed quality assurance program by the Japanese electric companies, BWR Operator Training Center (BTC) identified the needs to enhance operators' knowledge and skills for operations tasks during annual outage, and started to develop a dedicated operator training course specialized for them. In this paper, we present the total framework of the training course for annual outage operations and the associated typical three functions of our full-scope simulators specially developed and upgraded to conduct the training; namely, (1) Simulation model upgrade for the flow and temperature behavior concerning residual heat removal (RHR) system with shutdown cooling mode, (2) Addition of malfunctions for DC power supply equipment, (3) Simulation model upgrade for water filling operation for reactor pressurization (future development). We have implemented a trial of the training course by using the upgraded 800MW full-scope training simulator with functions (1) and (2) above. As the result of this trial, we are confident that the developed training course is effective for enhancing operators' knowledge and skills for operations tasks during annual outage. (author)

  14. In-situ monitoring of curing and ageing effects in FRP plates using embedded FBG sensors

    Science.gov (United States)

    Xian, Guijun; Wang, Chuan; Li, Hui

    2010-04-01

    In recent years, fiber reinforced polymer (FRP) composites have been widely applied in civil engineering for retrofitting or renewal of existing structures. Since FRP composite may degrade when exposed to severe outdoor environments, a serious concern has been raised on its long term durability. In the present study, fiber Bragg grating (FBG) sensors were embedded in glass-, carbon- and basalt-fiber reinforced epoxy based FRP plates with wet lay-up technology, to in-situ monitor the stain changes in FRPs during the curing, and water immersion and freeze-thaw ageing processes. The study demonstrates that the curing of epoxy resin brings in a slight tension strain (e.g., 10 ~ 30 μɛ) along the fiber direction and a high contraction (e.g., ~ 1100μɛ) in the direction perpendicular to the fibers, mainly due to the resin shrinkage. The cured FRP strips were then subjected to distilled water immersion at 80oC and freeze-thaw cycles from -30°C to 30°C. Remarkable strain changes of FRPs due to the variation of the temperatures during freeze-thaw cycles indicate the potential property degradation from fatigue. The maximum strain change is dependent on the fiber types and directions to the fiber. Based on the monitored strain values with temperature change and water uptake content, CTE (coefficient of thermal expansion) and CME (coefficient of moisture expansion) are exactly determined for the FRPs.

  15. Evaluation of Fiber Optic Strain Measurement System for Monitoring FRP Bridge Decks

    Science.gov (United States)

    Klinkhachorn, P.; Lonkar, G. M.; Halabe, Udaya B.; GangaRao, H. V. S.

    2005-04-01

    The use of Fiber Optic sensors for structural monitoring applications has attained popularity among researchers and practitioners recently due to their immense advantages. This paper discusses a continuous structural monitoring technique using surface mounted and embedded fiber optic strain sensors to measure the strain in FRP bridge decks. An Extrinsic Fabry-Perot Interferometric (EFPI) strain sensor was selected for evaluation as it offers a good compromise between accuracy and cost considerations. This EFPI strain sensor, along with a conventional strain gauge, was surface mounted on a FRP bridge decks. The decks were then subjected to an accelerated aging test in an environmental chamber and the performance of both the strain sensors was recorded for a performance comparison. The results from the seven months of accelerated aging that is equivalent to 10 years of actual life show that the strain gauge sensor and the EFPI Fiber Optic sensor are still in working condition. The EFPI fiber optic sensor detects minute and sudden changes in strain more effectively than the strain gauge sensor. Placement in the environmental chamber did not affect the EFPI sensor's performance and is an indication of its applicability to field structural monitoring for lengthy periods of time. The second part is a preliminary work where a fiber optic sensor was embedded inside a FRP plate during the pultrusion process. This shows the feasibility of manufacturing FRP bridge decks with embedded fiber optic sensors.

  16. Concrete Open-Wall Systems Wrapped with FRP under Torsional Loads

    Directory of Open Access Journals (Sweden)

    Valentino P. Berardi

    2012-10-01

    Full Text Available The static behavior of reinforced concrete (RC beams plated with layers of fiber-reinforced composite material (FRP is widely investigated in current literature, which deals with both its numerical modeling as well as experiments. Scientific interest in this topic is explained by the increasing widespread use of composite materials in retrofitting techniques, as well as the consolidation and upgrading of existing reinforced concrete elements to new service conditions. The effectiveness of these techniques is typically influenced by the debonding of the FRP at the interface with concrete, where the transfer of stresses occurs from one element (RC member to the other (FRP strengthening. In fact, the activation of the well-known premature failure modes can be regarded as a consequence of high peak values of the interfacial interactions. Until now, typical applications of FRP structural plating have included cases of flexural or shear-flexural strengthening. Within this context, the present study aims at extending the investigation to the case of wall-systems with open cross-section under torsional loads. It includes the results of some numerical analyses carried out by means of a finite element approximation.

  17. Time-dependent behavior of RC beams strengthened with externally bonded FRP plates: interfacial stresses analysis

    Science.gov (United States)

    Benyoucef, S.; Tounsi, A.; Benrahou, K. H.; Adda Bedia, E. A.

    2007-12-01

    External bonding of fibre reinforced polymer (FRP) composites has becomes a popular technique for strengthening concrete structures all over the world. An important failure mode of such strengthened members is the debonding of the FRP plate from the concrete due to high interfacial stresses near the plate ends. For correctly installed FRP plate, failure will occur within the concrete. Accurate predictions of the interfacial stresses are prerequisite for designing against debonding failures. In particular, the interfacial stresses between a beam and soffit plate within the linear elastic range have been addressed by numerous analytical investigations. In this study, the time-dependent behavior of RC beams bonded with thin composite plate was investigated theoretically by including the effect of the adherend shear deformations. The time effects considered here are those that arise from shrinkage and creep deformations of the concrete. This paper presents an analytical model for the interfacial stresses between RC beam and a thin FRP plate bonded to its soffit. The influence of creep and shrinkage effect relative to the time of the casting and the time of the loading of the beams is taken into account. Numerical results from the present analysis are presented to illustrate the significance of time-dependent of adhesive stresses.

  18. Crack detection and fatigue related delamination in FRP composites applied to concrete

    Science.gov (United States)

    Brown, Jeff; Baker, Rebecca; Kallemeyn, Lisa; Zendler, Andrew

    2008-03-01

    Reinforced concrete beams are designed to allow minor concrete cracking in the tension zone. The severity of cracking in a beam element is a good indicator of how well a structure is performing and whether or not repairs are needed to prevent structural failure. FRP composites are commonly used to increase the flexural and shear capacity of RC beam elements, but one potential disadvantage of this method is that strengthened surfaces are no longer visible and cracks or delaminations that result from excessive loading or fatigue may go undetected. This research investigated thermal imaging techniques for detecting load induced cracking in the concrete substrate and delamination of FRP strengthening systems applied to reinforced concrete (RC). One small-scale RC beam (5 in. x 6 in. x 60 in.) was strengthened with FRP and loaded to failure monotonically. An infrared thermography inspection was performed after failure. A second strengthened beam was loaded cyclically for 1,750,000 cycles to investigate how fatigue might affect substrate cracking and delamination growth throughout the service-life of a repaired element. No changes were observed in the FRP bond during/after the cyclic loading. The thermal imaging component of this research included pixel normalization to enhance detectability and characterization of this specific type of damage.

  19. The process of NPP refuelling outage analysis and follow-up

    International Nuclear Information System (INIS)

    Following the outages in 2004 and 2006, the Slovenian Nuclear Safety Administration (SNSA) has started with the practice of independent outage analysis in a form of an internal report. It includes a comparison of performed activities against the planned time schedule of activities, evaluation of design modifications implementation and analysis of significant events. The main result of the outage analysis is a list of recommendations and some open issues that have been identified. These findings are the basis for development of an action plan for SNSA activities until the next outage, aimed at eliminating deficiencies found out during the outage and further improving outage activities. The established system of outage supervision together with the final analysis and long term action plan represents an effective continuous safety supervision process, by which the regulatory body independently contributes to the higher level of safety culture both at the licensee and among its own staff. (author)

  20. Compound Outage Probability and Capacity of a Class of Fading MIMO Channels with Channel Distribution Uncertainty

    CERN Document Server

    Ioannou, Ioanna; Loyka, Sergey

    2011-01-01

    Outage probability and capacity of a class of block-fading MIMO channels are considered with partial channel distribution information. Specifically, the channel or its distribution are not known but the latter is known to belong to a class of distributions where each member is within a certain distance (uncertainty) from a nominal distribution. Relative entropy is used as a measure of distance between distributions. Compound outage probability defined as min (over the transmit signal distribution) -max (over the channel distribution class) outage probability is introduced and investigated. This generalizes the standard outage probability to the case of partial channel distribution information. Compound outage probability characterization (via one-dimensional convex optimization), its properties and approximations are given. It is shown to have two-regime behavior: when the nominal outage probability decreases (e.g. by increasing the SNR), the compound outage first decreases linearly down to a certain threshol...

  1. Performance Shaping Factors Assessments and Application to PHWR Outages

    International Nuclear Information System (INIS)

    Human reliability analysis is definitely related to the quality of PSA because human errors have been identified as major contributors to PSA. According to NRC's 'Office of analysis and evaluation of operational data (AEOD)',82% of the reactor trips and accident during outage is caused by the events related to human errors. There is, however, no one HRA method universally accepted. Furthermore, HRA during PHWR outages has not been performed around the world yet. HRA during PHWR outages is especially important since manual management of operator is more required during PHWR. In this study, accident scenarios which HYU developed are used to perform a quantification of human error probability. In this study, overall procedures of standard HRA methodology are introduced and follows the quantification of 10 possible selected human actions during PHWR outages based on standard HRA methodology. To see the verification, quantified values were compared with the values from 'Generic CANDU Probabilistic Safety Assessment' and the values estimated by ASEP.Core Damage Frequency was estimated 3.35 x 10-4 more higher than CDF estimated by AECL data. It was considered that the differences between the HEPs for OPAFW and OPECC3 make CDF higher. Therefore, complementary study of reestimating HEP for OPAFW and OPECC3 in detail is required for increasing the qualities of HRA and PSA. Moreover, one of the difficulties in performing human reliability analysis is to evaluate performance shaping factors which represent the characteristics and circumstances. For assessing a specific human action more exactly, it is necessary to consider all of the PSFs at the same time which makes an effect on the human action. Also, it requires the effect comparison among PSFs to minimize the uncertainties which are usually caused by the subjective judgements of HRA analysts. To see the sensitivity, performance shaping factors of each decision rule are changed which resulted in changes of core damage

  2. Parametric Study of Shear Strength of Concrete Beams Reinforced with FRP Bars

    Science.gov (United States)

    Thomas, Job; Ramadass, S.

    2016-06-01

    Fibre Reinforced Polymer (FRP) bars are being widely used as internal reinforcement in structural elements in the last decade. The corrosion resistance of FRP bars qualifies its use in severe and marine exposure conditions in structures. A total of eight concrete beams longitudinally reinforced with FRP bars were cast and tested over shear span to depth ratio of 0.5 and 1.75. The shear strength test data of 188 beams published in various literatures were also used. The model originally proposed by Indian Standard Code of practice for the prediction of shear strength of concrete beams reinforced with steel bars IS:456 (Plain and reinforced concrete, code of practice, fourth revision. Bureau of Indian Standards, New Delhi, 2000) is considered and a modification to account for the influence of the FRP bars is proposed based on regression analysis. Out of the 196 test data, 110 test data is used for the regression analysis and 86 test data is used for the validation of the model. In addition, the shear strength of 86 test data accounted for the validation is assessed using eleven models proposed by various researchers. The proposed model accounts for compressive strength of concrete (f ck ), modulus of elasticity of FRP rebar (E f ), longitudinal reinforcement ratio (ρ f ), shear span to depth ratio (a/d) and size effect of beams. The predicted shear strength of beams using the proposed model and 11 models proposed by other researchers is compared with the corresponding experimental results. The mean of predicted shear strength to the experimental shear strength for the 86 beams accounted for the validation of the proposed model is found to be 0.93. The result of the statistical analysis indicates that the prediction based on the proposed model corroborates with the corresponding experimental data.

  3. LSA SAF Meteosat FRP products - Part 2: Evaluation and demonstration for use in the Copernicus Atmosphere Monitoring Service (CAMS)

    Science.gov (United States)

    Roberts, G.; Wooster, M. J.; Xu, W.; Freeborn, P. H.; Morcrette, J.-J.; Jones, L.; Benedetti, A.; Jiangping, H.; Fisher, D.; Kaiser, J. W.

    2015-11-01

    Characterising the dynamics of landscape-scale wildfires at very high temporal resolutions is best achieved using observations from Earth Observation (EO) sensors mounted onboard geostationary satellites. As a result, a number of operational active fire products have been developed from the data of such sensors. An example of which are the Fire Radiative Power (FRP) products, the FRP-PIXEL and FRP-GRID products, generated by the Land Surface Analysis Satellite Applications Facility (LSA SAF) from imagery collected by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard the Meteosat Second Generation (MSG) series of geostationary EO satellites. The processing chain developed to deliver these FRP products detects SEVIRI pixels containing actively burning fires and characterises their FRP output across four geographic regions covering Europe, part of South America and Northern and Southern Africa. The FRP-PIXEL product contains the highest spatial and temporal resolution FRP data set, whilst the FRP-GRID product contains a spatio-temporal summary that includes bias adjustments for cloud cover and the non-detection of low FRP fire pixels. Here we evaluate these two products against active fire data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) and compare the results to those for three alternative active fire products derived from SEVIRI imagery. The FRP-PIXEL product is shown to detect a substantially greater number of active fire pixels than do alternative SEVIRI-based products, and comparison to MODIS on a per-fire basis indicates a strong agreement and low bias in terms of FRP values. However, low FRP fire pixels remain undetected by SEVIRI, with errors of active fire pixel detection commission and omission compared to MODIS ranging between 9-13 % and 65-77 % respectively in Africa. Higher errors of omission result in greater underestimation of regional FRP totals relative to those derived from simultaneously collected MODIS

  4. Analysis of the Dependence of Power Outages on Lightning Events within the Ijebu Province, Nigeria

    Directory of Open Access Journals (Sweden)

    J.O. Adepitan

    2012-09-01

    Full Text Available The study aimed at developing a model for lightning-induced outages in Nigeria from results obtained on determining the proportion and rate of lightning-induced outages out of the total power outages experienced in Ijebu province of Nigeria. Power outage records for Ijebu province, comprising Ijebu-Ode and Sagamu areas, Ogun state, Nigeria for the years 2002-2006 were collected from Power Holding Company of Nigeria (PHCN. Unintentional stochastic outages were separated from those due to deliberate load shedding. Lightning events records were collected from Nigeria Meteorological Agency for the same period. The two sets of time series were superimposed. Outages with time, t6 min were classified as ‘Others’ (OT. The two sets of data were analyzed in order to determine percentage of lightning-induced outagfes. Also, thunderstorm days and power line parameters were used as input data for modified FLASH 1.7 software (considering tropical region to estimate the rate of lightning induced outages. The five-year period, 2002 to 2006, experienced no significant difference (p<0.05 in the mean of percentage of LI outages for both areas, calculated as 8.6 for Ijebu-Ode and 9.5 for Sagamu. The corresponding values for PLI being 1 and 2%; whereas OT had values 90.4 and 88.5%. Where earth wires were available on the transmission lines, the mafn lightning-induced outage rate was 1/100 km-year. The mean flashover rate for unshielded lines was 22/100 km-year. A linear relationship was established between the annual lightning-induced outages and the annual lightning days for the province. Lightning accounted for approximately 10% of the random outages experienced in Ijebu province. Lightning-induced outages are linearly related to lightning days. Lightning-induced outage rate is much higher over unshielded than shielded transmission lines.

  5. Design Concepts for an Outage Control Center Information Dashboard

    International Nuclear Information System (INIS)

    The nuclear industry, and the business world in general, is facing a rapidly increasing amount of data to be dealt with on a daily basis. In the last two decades, the steady improvement of data storage devices and means to create and collect data along the way influenced the manner in which we deal with information. Most data is still stored without filtering and refinement for later use. Many functions at a nuclear power plant generate vast amounts of data, with scheduled and unscheduled outages being a prime example of a source of some of the most complex data sets at the plant. To make matters worse, modern information and communications technology is making it possible to collect and store data faster than our ability to use it for making decisions. However, in most applications, especially outages, raw data has no value in itself; instead, managers, engineers and other specialists want to extract the information contained in it. The complexity and sheer volume of data could lead to information overload, resulting in getting lost in data that may be irrelevant to the task at hand, processed in an inappropriate way, or presented in an ineffective way. To prevent information overload, many data sources are ignored so production opportunities are lost because utilities lack the ability to deal with the enormous data volumes properly. Decision-makers are often confronted with large amounts of disparate, conflicting and dynamic information, which are available from multiple heterogeneous sources. Information and communication technologies alone will not solve this problem. Utilities need effective methods to exploit and use the hidden opportunities and knowledge residing in unexplored data resources. Superior performance before, during and after outages depends upon the right information being available at the right time to the right people. Acquisition of raw data is the easy part; instead, it is the ability to use advanced analytical, data processing and data

  6. Design Concepts for an Outage Control Center Information Dashboard

    Energy Technology Data Exchange (ETDEWEB)

    Hugo, Jacques Victor [Idaho National Lab. (INL), Idaho Falls, ID (United States); St Germain, Shawn Walter [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thompson, Cheradan Jo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Whitesides, McKenzie Jo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Farris, Ronald Keith [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-12-01

    The nuclear industry, and the business world in general, is facing a rapidly increasing amount of data to be dealt with on a daily basis. In the last two decades, the steady improvement of data storage devices and means to create and collect data along the way influenced the manner in which we deal with information. Most data is still stored without filtering and refinement for later use. Many functions at a nuclear power plant generate vast amounts of data, with scheduled and unscheduled outages being a prime example of a source of some of the most complex data sets at the plant. To make matters worse, modern information and communications technology is making it possible to collect and store data faster than our ability to use it for making decisions. However, in most applications, especially outages, raw data has no value in itself; instead, managers, engineers and other specialists want to extract the information contained in it. The complexity and sheer volume of data could lead to information overload, resulting in getting lost in data that may be irrelevant to the task at hand, processed in an inappropriate way, or presented in an ineffective way. To prevent information overload, many data sources are ignored so production opportunities are lost because utilities lack the ability to deal with the enormous data volumes properly. Decision-makers are often confronted with large amounts of disparate, conflicting and dynamic information, which are available from multiple heterogeneous sources. Information and communication technologies alone will not solve this problem. Utilities need effective methods to exploit and use the hidden opportunities and knowledge residing in unexplored data resources. Superior performance before, during and after outages depends upon the right information being available at the right time to the right people. Acquisition of raw data is the easy part; instead, it is the ability to use advanced analytical, data processing and data

  7. Effects of Elevated Temperatures on the Compressive Strength Capacity of Concrete Cylinders Confined with FRP Sheets: An Experimental Investigation

    OpenAIRE

    Sherif El-Gamal; Khalifa Al-Jabri; Ahmed Al-Mahri; Saud Al-Mahrouqi

    2015-01-01

    Due to their high strength, corrosion resistance, and durability, fiber reinforced polymers (FRP) are very attractive for civil engineering applications. One of these applications is the strengthening of concrete columns with FRP sheets. The performance of this strengthening technique at elevated temperature is still questionable and needs more investigations. This research investigates the effects of exposure to high temperatures on the compressive strength of concrete cylinders wrapped with...

  8. A Design-Oriented Combined Model (7 MPa to 190 MPa) for FRP-Confined Circular Short Columns

    OpenAIRE

    Zehra Canan Girgin; Konuralp Girgin

    2015-01-01

    This study addresses a design oriented combined model to predict the ultimate strengths and ultimate strains in an extensive range of unconfined strength (7 to 190 MPa) for the axially loaded fiber-reinforced polymer (FRP)-wrapped circular short columns. Modified Hoek-Brown strength criterion, which was previously extended to FRP-confined concrete from 7 to 108 MPa, is revisited and verified. An empirical strength model beyond 108 MPa encompassing ultra-high strength concrete (UHSC) and ultra...

  9. Numerical study of the role of mortar joints in the bond behavior of FRP-strengthened masonry

    OpenAIRE

    Ghiassi, Bahman; Oliveira, Daniel V.; Lourenço, Paulo B.; Marcari, Giancarlo

    2013-01-01

    The performance of the interface between FRP and masonry is one of the key factors affecting the behavior of strengthened masonry elements. Therefore, a sound understanding of the interface behavior is crucial at the design stage. In this paper, the effect of mortar joints in the bond behavior of FRP-strengthened masonry prisms is investigated through numerical modeling. The numerical simulation is performed by adopting a nonlinear three-dimensional micro-modeling approach. Different smeared ...

  10. A damage model to predict the durability of bonded assemblies. Part I : Debonding behavior of FRP strengthened concrete structures

    OpenAIRE

    Benzarti, Karim; Freddi, Francesco; Fremond, Michel

    2011-01-01

    Presented in this paper is a coupled damage model to predict the durability of concrete elements strengthened by external bonding of fiber reinforced polymer (FRP) plates. Both the concrete, the strengthening FRP and the glue are modeled as damageable materials. The damage model is developed within the framework of the principle of virtual power. The adopted power of the internal forces depends on the damage velocity and on its gradient to take into account local interactions. An interaction ...

  11. Modified Johnston Failure Criterion from Rock Mechanics to Predict the Ultimate Strength of Fiber Reinforced Polymer (FRP) Confined Columns

    OpenAIRE

    Zehra Canan Girgin

    2013-01-01

    The failure criteria from rock mechanics, Hoek-Brown and Johnston failure criteria, may be extended and modified to assess the ultimate compressive strength of axially loaded circular fiber reinforced polymer (FRP)-confined concrete columns. In addition to the previously modified Hoek-Brown criterion, in this study, the Johnston failure criterion is extended to scope of FRP-confined concrete, verified with the experimental data and compared with the significant relationships from the current ...

  12. Overview of Pickering NGS Units 1 and 2 retube outage

    International Nuclear Information System (INIS)

    After the Pickering NGS Unit 2 pressure tube failure in August 1983, a decision was made in March 1984 to replace all the pressure tubes from both Unit 1 and Unit 2. This retubing was accomplished over a three year period, together with a program of inspection, maintenance, and modification on other systems. Equipment was put in a short term mothballed state at the commencement of the outage, and a thorough recommissioning of all systems, both old and new, was carried out during restart. This paper provides an overview of the program, highlighting successes and difficulties, and recommending changes for future retubing projects

  13. Minimizing maintenance and outage time with an automated tagging system

    International Nuclear Information System (INIS)

    Public Service Electric and Gas Company has developed a computerized ''Tagging Request and Inquiry System'' (TRIS) to support maintenance tagging operations and valve alignment operations at all of its nuclear and fossil power plants. The system was first placed in service in June 1981 at the Salem Nuclear Power Plant. TRIS tracks the operational status of plant components (valves, breakers, etc.). It is a comprehensive system involving six major function menus, 50 data input screens, 35 screen outputs, and 66 reports. By eliminating much of the weakness inherent in manual tagging and alignment procedures, TRIS reduces maintenance outage durations, improves plant safety, and minimizes the possibility of errors

  14. Lay-up condition during ENPP refurbishment outage

    International Nuclear Information System (INIS)

    Embalse Nuclear Power Plant (ENPP) is a CANDU® 6 type with 648 MWe output with the First Criticality in 1983, and 100% Power in September 1983. The plant was designed and licensed to operate during 24 Effective Full Power Years (EFPY) As it is getting close to the end of the design life, it was decided to implement the necessary tasks for a Plant Life Extension (PLEX) Project. The PLEX Project includes 3 Phases: Phase I: Prioritization and Analysis, Phase II: Project Engineering, and Phase III: Implementation. (See Figure 1) During Phase III in the PLEX Proyect, many components will be replaced, and many Systems, Structures and Components (SSC) need to be inspected/refurbished (e.g. Reactor Retubing, Steam Generators Cartridge replacement, inspections and maintenance of large components (as pipes, pumps, heat exchangers), station systems configuration will be totally different from normal operating conditions. Even when some Systems have conservation facilities and procedures these are thought for normal maintenance outage. During the refurbishment outage the condition on those components can change and lead the SSC exposed to abnormal aggressive conditions, as an oxidizing atmosphere due to the air ingress to the system (the stressors could be increased). Consequently the Aging Related Degradation Mechanisms (ARDM) can be accelerated limiting the remaining life of these components.Then it is very important to implement an adequate Lay Up Condition Program. During the implementation of a Lay Up refurbished Condition Program a prioritization of systems and / or more relevant components requiring special conservation will be done. Then a review of the chemical specifications to analyze while lay up methods should be applied. From the PLEX phase I, scope definition, it was identified equipment to be replaced or requiring certain inspections during the refurbishment outage, the possible interference and conditions needed for implementation depending on the method

  15. Permanent start-up instrumentation for maintenance outages

    International Nuclear Information System (INIS)

    This paper assesses the need and feasibility of permanent start-up instrumentation detectors to monitor photoneutron flux during maintenance outages. CANDU ion chamber systems were designed to remain on scale for ten weeks after reactor shutdown. A requirement was imposed in the mid-1990s to put the reactor into an overpoisoned guaranteed shutdown state whenever it is shut down and not actively undergoing a restart. Due to the high gadolinium concentration, the ion chamber systems go off scale within three weeks. Operating policies and procedures require the neutron flux and its rate of change to be monitored when fuel is in the reactor. (author)

  16. Analysis of Fixed Outage Transmission Schemes: A Finer Look at the Full Multiplexing Point

    CERN Document Server

    Wu, Peng

    2007-01-01

    This paper studies the performance of transmission schemes that have rate that increases with average SNR while maintaining a fixed outage probability. This is in contrast to the classical Zheng-Tse diversity-multiplexing tradeoff (DMT) that focuses on increasing rate and decreasing outage probability. Three different systems are explored: antenna diversity systems, time/frequency diversity systems, and automatic repeat request (ARQ) systems. In order to accurately study performance in the fixed outage setting, it is necesary to go beyond the coarse, asymptotic multiplexing gain metric. In the case of antenna diversity and time/frequency diversity, an affine approximation to high SNR outage capacity (i.e., multiplexing gain plus a power/rate offset) accurately describes performance and shows the very significant benefits of diversity. ARQ is also seen to provide a significant performance advantage, but even an affine approximation to outage capacity is unable to capture this advantage and outage capacity must...

  17. Cascading Power Outages Propagate Locally in an Influence Graph that is not the Actual Grid Topology

    CERN Document Server

    Hines, Paul D H; Rezaei, Pooya

    2015-01-01

    In a cascading power transmission outage, component outages propagate non-locally; after one component outages, the next failure may be very distant, both topologically and geographically. As a result, simple models of topological contagion do not accurately represent the propagation of cascades in power systems. However, cascading power outages do follow patterns, some of which are useful in understanding and reducing blackout risk. This paper describes a method by which the data from many cascading failure simulations can be transformed into a graph-based model of influences that provides actionable information about the many ways that cascades propagate in a particular system. The resulting "influence graph" model is Markovian, since component outage probabilities depend only on the outages that occurred in the prior generation. To validate the model we compare the distribution of cascade sizes resulting from n-2 contingencies in a 2896 branch test case to cascade sizes in the influence graph. The two dist...

  18. Outage Probability of General Ad Hoc Networks in the High-Reliability Regime

    CERN Document Server

    Giacomelli, Riccardo; Haenggi, Martin

    2010-01-01

    Outage probabilities in wireless networks depend on various factors: the node distribution, the MAC scheme, and the models for path loss, fading and transmission success. In prior work on outage characterization for networks with randomly placed nodes, most of the emphasis was put on networks whose nodes are Poisson distributed and where ALOHA is used as the MAC protocol. In this paper we provide a general framework for the analysis of outage probabilities in the high-reliability regime. The outage probability characterization is based on two parameters: the intrinsic spatial contention $\\gamma$ of the network, introduced in [1], and the coordination level achieved by the MAC as measured by the interference scaling exponent $\\kappa$ introduced in this paper. We study outage probabilities under the signal-to-interference ratio (SIR) model, Rayleigh fading, and power-law path loss, and explain how the two parameters depend on the network model. The main result is that the outage probability approaches $\\gamma\\e...

  19. On Outage Performance of Spectrum-Sharing Communication over M-Block Fading

    KAUST Repository

    Alabbasi, AbdulRahman

    2015-12-06

    In this paper, we consider a cognitive radio system in which a block-fading channel is assumed. Each transmission frame consists of M blocks and each block undergoes a different channel gain. Instantaneous channel state information about the interference links remains unknown to the primary and secondary users. We minimize the secondary user\\'s targeted outage probability over the block-fading channels. To protect the primary user, a statistical constraint on its targeted outage probability is enforced. The secondary user\\'s targeted outage region and the corresponding optimal power are derived. We also propose two sub-optimal power strategies and derive compact expressions for the corresponding outage probabilities. These probabilities are shown to be asymptotic lower and upper bounds on the outage probability. Utilizing these bounds, we derive the exact diversity order of the secondary user outage probability. Selected numerical results are presented to characterize the system\\'s behavior.

  20. Barras de FRP: avaliando o módulo de elasticidade não destrutivamente FRP bars: assesing elastic modulus nondestructively

    Directory of Open Access Journals (Sweden)

    Protasio F Castro

    1997-06-01

    Full Text Available Um estudo experimental foi realizado com o objetivo de contribuir com o desenvolvimento de métodos de ensaios de avaliação das características mecânicas das barras de plástico reforçado com fibra (FRP a serem utilizadas como armadura nas obras de engenharia civil. Comparou-se o módulo de elasticidade estático, obtido por ensaio de tração em uma máquina universal, com o módulo de elasticidade dinâmico, obtido por ensaios não destrutivos. O módulo de elasticidade dinâmico foi determinado utilizando-se dois métodos de propagação de ondas: o pulso ultra-sônico e a freqüência de ressonância. Os valores do módulo de elasticidade dinâmico e os valores do módulo de elasticidade estático obtidos a partir da curva tensão-deformação dos ensaios de tração são significativamente semelhantes. Os resultados mostram que os ensaios de módulo de elasticidade dinâmico possuem potencial para serem utilizados na linha de fabricação das barras de FRP como controle da produção.An experimental study was carried out to support the development of standards test methods for fiber reinforced plastic (FRP bars used as concrete reinforcement. In addition, this study compares the elastic modulus values from tensile stress-strain curves with the dynamic values obtained nondestructively. Dynamic modulus of elasticity was determined using two stress wave propagation methods: ultrasonic pulse velocity and resonant frequency. The dynamic values compared favorably with values obtained from tensile stress-strain curves. The results showed the feasibility of using nondestructive methods, as control test, to estimate FRP bars elastic modulus in a manufacture process.

  1. Cognitive Proactive and Reactive DF Relaying Schemes under Joint Outage and Peak Transmit Power Constraints

    OpenAIRE

    Tran, Hung; Zepernick, Hans-Jürgen; Phan, Hoc

    2013-01-01

    In this paper, outage performance of cognitive cooperative radio networks using two decode-and-forward (DF) schemes is investigated. Subject to the joint outage constraint of the primary user and the peak transmit power constraint of the secondary user, adaptive power allocation policies for the secondary transmitter and secondary relays are studied. Based on these strategies, expressions for the outage probability of proactive and reactive DF schemes are obtained. Interestingly, our results ...

  2. FRP 筋纤维混凝土受弯构件试验研究%An Experimental Study of Flexural Behaviour of FRP Reinforced Fiber Concrete Flexural Components

    Institute of Scientific and Technical Information of China (English)

    熊明权; 邱振清; 郑愚; 周日瑜

    2013-01-01

    In the current FRP flexural components , FRP is used as longitudinal tensile materials with large quantity .There-fore, the construction cost is huge and the structural design is determined by deflection but not by strength , which is due to low stiff-ness.In this study, fiber concrete will be introduced to FRP reinforced concrete beams with the consideration of high tensile strength of reinforcing materials .The influences of fibers on ductility and deformation of FRP reinforced concrete flexural components is in -vestigated by experimental tests .It turns out that the increasing of fibers in concrete materials can enhance the deformation of FRP reinforced concrete beams in order to solve problems of high reinforcement percentages in FRP reinforced concrete flexural compo -nents caused by the low structural ductility .Due to the difference between FRP and steel , ductility factor for FRP reinforced con-crete structures is established .With this ductility factor , the increasing of fiber quantity can improve the ductility of FRP reinforced flexural elements .%现有采用FRP的受弯构件中, FRP作为主要纵向受拉材料,用量通常较大。这造成FRP筋混凝土构件成本较高,同时还因构件刚度不够导致其变形而非承载力成为设计的控制因素。为了充分发挥FRP材料良好的抗拉性能,建立了FRP筋纤维混凝土受弯构件。通过结构试验的方法研究纤维混凝土对FRP筋混凝土受弯构件延性及变形能力的影响。试验结果表明,纤维的增加能够有效提高FRP筋受弯构件的变形能力,解决了过去FRP筋受弯构件延性差导致配筋率过高的问题。基于FRP筋与钢筋材料上的差异,针对FRP筋混凝土构件建立了相应的延性设计指标。采用该指标对纤维混凝土构件进行分析后发现,随着纤维含量的增加, FRP筋混凝土受弯构件的延性有着明显提高。

  3. Operation and maintenance outage experience of reactor internal pump

    International Nuclear Information System (INIS)

    The No.6 unit of Tokyo Electric Power Company's Kashiwazaki-Kariwa Nuclear Power Station (K-6), the first advanced boiling water reactor (ABWR), turned over on November 1996. One of the major design features of ABWR is a reactor internal pump (RIP). Ten RIPs are mounted at the bottom of a reactor pressure vessel (RPV) so as to circulate reactor water directly to the reactor core. All RIPs have been successfully operating through the first and second plant operating cycles. In the first outage, two RIPs among them were maintained according to plan. Two sets of the impeller and shaft were removed in series into the fuel pool and examined at visual tests. Two motors were also removed in series to the maintenance area and disassembled to parts for visual and/or dimensional tests. No harm was found as the results of the tests. Two other spare motors were installed instead of the above two examined motors as the advanced procedure according to plan. All RIPs were operated in high speed condition at the end of the outage. The monitored data of each RIP were confirmed to the good operation in the second cycle. (author)

  4. Availability and outage frequency of repairable parallel unit systems

    International Nuclear Information System (INIS)

    This contribution evolved directly from the application of reliability and maintainability analysis in the design of the Gentilly-2 nuclear power station. This station employs a 600 MWe Candu type pressurized heavy water reactor. During the design stage decisions have to be made regarding the configuration of systems which consists of a number of units in parallel. The criteria used in making these decisions are: safety, economics (capital cost and operating efficiency, reliability and maintainability, which can be expressed numerically as availability and outage frequency). This paper describes a method for analyzing the availability and outage frequency of systems consisting of a number of repairable units in parallel. The method is based on state transition models (a unit, whether it is the operating or the standby unit, can be in either of two states: healthy or in repair; the probability of being in either state is a function of the transition rates between the two states: failure rate and repair rate). The development of computer program Stram is presented, as well as some examples of program output

  5. Radiological protection for the ANGRA 1 steam generator replacement outage

    International Nuclear Information System (INIS)

    The Angra 1 Nuclear Power Plant (NPP) is a Westinghouse two-loop plant with net output before its 1P16 Outage of 632 MWe, with the Old Steam Generators (OSG) type model D3, which were replaced by two new Steam Generators with feed water-ring system. Localized in Angra dos Reis, Rio de Janeiro - Brazil, Angra 1 started in commercial operation in 1985 and, from the beginning problems related to corrosion have appeared in the Inconel 600 alloy of the tubes. The corrosion problems indicated the necessity for a strong control of the tubes thicknesses and, after a time, the ELETRONUCLEAR decided to replace the OSG. In 2009, ELETRONUCLEAR initiated in January 24, the actions for the Steam Generators Replacement - SGR. During the SGR process, several controls were applied in field, which made possible to have no radiological accidents, no dose limits exceeded, and permitted to achieve a very good result in terms of Collective Dose. This paper describes the radiological controls applied for the Angra 1 Steam Generator Replacement Outage, the radiological protection team sizing and distribution and the obtained results. (author)

  6. Long-range outage planning - A strategy for success

    International Nuclear Information System (INIS)

    The nuclear power industry, already beset by reduced demand, environmental concerns, regulatory-initiated modifications, increased operations costs, and other cost-affecting factors, is now entering a new era. Electric utilities in general and the nuclear utilities in particular are facing the specter of competition, until now a facet of the business world they have seldom had to confront in their geographically defined, independent service areas. The force of competition stems not only from other utilities but also from alternative fuels, and from utility customers. In light of this climate of competition, the utilities must seek to control operating costs, to maintain or improve plant availability and reliability, and to assess and schedule the requirements imposed by the US Nuclear Regulatory Commission (NRC) and by needed maintenance activities. In particular, the need to control the many regulatory proposed plant modifications and inspections on a plant-specific basis has prompted the development of the living schedule concept. This paper presents the subject of long-range outage planning as a means of dealing with the futurity of present operating decisions and a method of achieving quality outages

  7. Outage analysis for underlay cognitive networks using incremental regenerative relaying

    KAUST Repository

    Tourki, Kamel

    2013-02-01

    Cooperative relay technology has recently been introduced into cognitive radio (CR) networks to enhance the network capacity, scalability, and reliability of end-to-end communication. In this paper, we investigate an underlay cognitive network where the quality of service (QoS) of the secondary link is maintained by triggering an opportunistic regenerative relaying once it falls under an unacceptable level. Analysis is conducted for two schemes, referred to as the channel-state information (CSI)-based and fault-tolerant schemes, respectively, where different amounts of CSI were considered. We first provide the exact cumulative distribution function (cdf) of the received signal-to-noise ratio (SNR) over each hop with colocated relays. Then, the cdf\\'s are used to determine a very accurate closed-form expression for the outage probability for a transmission rate $R$. In a high-SNR region, a floor of the secondary outage probability occurs, and we derive its corresponding expression. We validate our analysis by showing that the simulation results coincide with our analytical results in Rayleigh fading channels. © 1967-2012 IEEE.

  8. A design model for strain-softening and strain-hardening fiber reinforced elements reinforced longitudinally with steel and FRP bars

    OpenAIRE

    Mahsa, Taheri; Barros, Joaquim A. O.; Salehian, Hamidreza

    2011-01-01

    A close form solution is developed for the prediction of the moment-curvature relationship of cross sections of fiber reinforced concrete (FRC) elements failing in bending, and reinforced longitudinally with steel and fiber reinforced polymer (FRP) bars. The FRP bars are installed with the largest possible internal arm, e.g. with the minimum concrete cover that assures the bond conditions for a sound stress transfer from FRC to the FRP bars. The model is also able of simulating th...

  9. Prediction of Flexural Capacity of RC Beams Strengthened in Flexure with FRP Fabric and Cementitious Matrix

    Directory of Open Access Journals (Sweden)

    Kyusan Jung

    2015-01-01

    Full Text Available This paper presents both experimental and analytical research results for predicting the flexural capacity of reinforced concrete (RC beams strengthened in flexure with fabric reinforced cementitious matrix (FRCM. In order to assess the efficiency of the FRCM-strengthening method, six beams were strengthened in flexure with FRCM composite having different amounts and layers of FRP fabric and were tested under four-point loading. From test results, it was confirmed that the slippage between the FRP fabric and matrix occurs at a high strain level, and all of the FRCM-strengthened beams failed by the debonding of the FRCM. Additionally, a new bond strength model for FRCM considering the slippage between fabric and matrix was proposed, using a test database to predict the strengthening performance of the FRCM composite. The prediction of the proposed bond strength model agreed well with the debonding loads of the test database.

  10. Strength Modeling of Reinforced Concrete Beam with Externally Bonded FRP Reinforcement

    OpenAIRE

    N. Pannirselvam; P. N. Ragunath; Suguna, K

    2008-01-01

    This research study presents the evaluation of the structural behaviour of reinforced concrete beams with externally bonded Fibre Reinforced Polymer (FRP) reinforcements. Three different steel ratios with two different Glass Fibre Reinforced Polymer (GFRP) types and two different thicknesses in each type of GFRP were used. Totally fifteen rectangular beams of 3 m length were cast. Three rectangular beams were used as reference beam (Control Beams) and the remaining were fixed with GFRP lamina...

  11. Damage model for FRP-confined concrete columns under cyclic loading

    OpenAIRE

    Desprez, Cédric; Mazars, Jacky; Kotronis, Panagiotis; PAULTRE, Patrick

    2013-01-01

    In structural engineering, seismic vulnerability reduction of existing structures is a crucial issue. External reinforcement with fiber-reinforced polymer (FRP) holds interest in achieving this aim. Its use as a retrofitting method is limited, however, for a number of reasons, including the lack of numerical tools for predicting cyclic loading. This paper presents a simplified stress–strain model suitable for monotonic and cycling loading capable of predicting the FRP’s effect on ...

  12. Meso-scale three-dimensional modeling of bond in FRP-strengthened masonry

    OpenAIRE

    Ghiassi, Bahman; Oliveira, Daniel V.; Lourenço, Paulo B.; Marcari, Giancarlo

    2012-01-01

    Performance of masonry elements externally strengthened with fiber reinforced polymers (FRPs) is intrinsically dependent on the bond behavior between the composite material and masonry substrate. Therefore, a sound understanding of the interface behavior is crucial at the design stage. In this paper, a three-dimensional model based on the smeared crack modeling approach is presented for investigating the bond behavior in FRP-strengthened masonry elements. The threedimensional aspects of bond ...

  13. Design procedures for the use of EB FRP in shear strengthening of reinforced concrete beams

    OpenAIRE

    Vasic, Mira

    2011-01-01

    The aim of this work is assessment and analysis of the reliability of the most well-known design models, available for the prediction of the contribution of fiber reinforced polymer (FRP) systems to the shear capacity of strengthened reinforced concrete beams. In this study, current analytical formulations for basic shear design and shear strengthening design are presented in detail and main problems and lacks, being the motivation of this work, are highlighted. The research is based on th...

  14. Combined Transverse Steel-External FRP Confinement Model for Rectangular Reinforced Concrete Columns

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Rahmani

    2016-02-01

    Full Text Available Recently, the need to increase the strength of reinforced concrete members has become a subject that civil engineers are interested in tackling. Of the many proposed solutions, fiber-reinforced polymer (FRP materials have attracted attention due to their superior properties, such as high strength-to-weight ratio, high energy absorption and excellent corrosion resistance. FRP wrapping of concrete columns is done to enhance the ultimate strength due to the confinement effect, which is normally induced by steel ties. The existence of the two confinement systems changes the nature of the problem, thus necessitating specialized nonlinear analysis to obtain the column’s ultimate capacity. Existing research focused on a single confinement system. Furthermore, very limited research on rectangular sections was found in the literature. In this work, a model to estimate the combined behavior of the two systems in rectangular columns is proposed. The calculation of the effective lateral pressure is based on the Lam and Teng model and the Mander model for FRP wraps and steel ties, respectively. The model then generates stress-strain diagrams for both the concrete core and the cover. The model was developed for the analysis in extreme load events, where all possible contributions to the column’s ultimate capacity should be accounted for without any margin of safety. The model was validated against experiments, and the results obtained showed good agreement with almost all of the available experimental data.

  15. Strength Modeling of Reinforced Concrete Beam with Externally Bonded FRP Reinforcement

    Directory of Open Access Journals (Sweden)

    N. Pannirselvam

    2008-01-01

    Full Text Available This research study presents the evaluation of the structural behaviour of reinforced concrete beams with externally bonded Fibre Reinforced Polymer (FRP reinforcements. Three different steel ratios with two different Glass Fibre Reinforced Polymer (GFRP types and two different thicknesses in each type of GFRP were used. Totally fifteen rectangular beams of 3 m length were cast. Three rectangular beams were used as reference beam (Control Beams and the remaining were fixed with GFRP laminates on the soffit of the rectangular beam. The variables considered for the study includes longitudinal steel ratio, type of GFRP laminates, thickness of GFRP laminates and composite ratios. Flexural test, using simple beam with third-point loading was adopted to study the performance of FRP plated beams interms flexural strength, deflection, ductility and was compared with the unplated beams. The test results show that the beams strengthened with GFRP laminates exhibit better performance. The flexural strength and ductility increase with increase in thickness of GFRP plate. The increase in first crack loads was up to 88.89% for 3 mm thick WRGFRP plates and 100.00% for 5 mm WRGFRP plated beams and increase in ductility interms of energy and deflection was found to be 56.01 and 64.69% respectively with 5 mm thick GFRP plated beam. Strength models were developed for predicting the flexural strength (ultimate load, service load and ductility of FRP beams. The strength model developed give prediction matching the measurements.

  16. Disbond detection with piezoelectric wafer active sensors in RC structures strengthened with FRP composite overlays

    Institute of Scientific and Technical Information of China (English)

    Victor Giurgiutiu; Kent Harries; Michael Petrou; Joel Bost; Josh B. Quattlebaum

    2003-01-01

    The capability of embedded piezoelectric wafer active sensors (PWAS) to perform in-situ nondestructive evaluation (NDE) for structural health monitoring (SHM) of reinforced concrete (RC) structures strengthened with fiber reinforced polymer (FRP) composite overlays is explored. First, the disbond detection method were developed on coupon specimens consisting of concrete blocks covered with an FRP composite layer. It was found that the prescnce of a disbond crack drastically changes the electromecbanical (E/M) impedance spectrum measured at the PWAS terminals. The spectral changes depend on the distance between the PWAS and the crack tip. Second, large scale experiments were conducted on a RC beam strengthened with carbon fiber reinforced polymer (CFRP) composite overlay. The beam was subject to an acccleratcd fatigue load regime in a three-point bending configuration up to a total of807,415 cycles. During these fatigue tests, the CFRP overlay experienced disbonding beginning at about 500,000 cycles. The PWAS were able to detect the disbonding before it could be reliably seen by visual inspection. Good correlation between the PWAS readings and the position and extent of disbond damage was observed. These preliminary results demonstrate the potential of PWAS technology for SHM of RC structures strengthened with FRP composite ovcrlays.

  17. Disbond detection with piezoelectric wafer active sensors in RC structures strengthened with FRP composite overlays

    Science.gov (United States)

    Giurgiutiu, Victor; Harries, Kent; Petrou, Michael; Bost, Joel; Quattlebaum, Josh B.

    2003-12-01

    The capability of embedded piezoelectric wafer active sensors (PWAS) to perform in-situ nondestructive evaluation (NDE) for structural health monitoring (SHM) of reinforced concrete (RC) structures strengthened with fiber reinforced polymer (FRP) composite overlays is explored. First, the disbond detection method were developed on coupon specimens consisting of concrete blocks covered with an FRP composite layer. It was found that the presence of a disbond crack drastically changes the electromechanical (E/M) impedance spectrum measured at the PWAS terminals. The spectral changes depend on the distance between the PWAS and the crack tip. Second, large scale experiments were conducted on a RC beam strengthened with carbon fiber reinforced polymer (CFRP) composite overlay. The beam was subject to an accelerated fatigue load regime in a three-point bending configuration up to a total of 807,415 cycles. During these fatigue tests, the CFRP overlay experienced disbonding beginning at about 500,000 cycles. The PWAS were able to detect the disbonding before it could be reliably seen by visual inspection. Good correlation between the PWAS readings and the position and extent of disbond damage was observed. These preliminary results demonstrate the potential of PWAS technology for SHM of RC structures strengthened with FRP composite overlays.

  18. Outage analysis for underlay relay-assisted cognitive networks

    KAUST Repository

    Tourki, Kamel

    2012-12-01

    Cooperative relay technology was recently introduced into cognitive radio networks in order to enhance network capacity, scalability, and reliability of end-to-end communication. In this paper, we investigate an underlay cognitive network where the quality of service of the secondary link is maintained by triggering an opportunistic regenerative relaying once it falls under an unacceptable level. We first provide the exact cumulative density function (CDF) of received signal-to-noise (SNR) over each hop with co-located relays. Then, the CDFs are used to determine very accurate closed-form expression for the outage probability for a transmission rate R. We validate our analysis by showing that simulation results coincide with our analytical results in Rayleigh fading channels. © 2012 IEEE.

  19. Braess's paradox in oscillator networks, desynchronization and power outage

    Science.gov (United States)

    Witthaut, Dirk; Timme, Marc

    2012-08-01

    Robust synchronization is essential to ensure the stable operation of many complex networked systems such as electric power grids. Increasing energy demands and more strongly distributing power sources raise the question of where to add new connection lines to the already existing grid. Here we study how the addition of individual links impacts the emergence of synchrony in oscillator networks that model power grids on coarse scales. We reveal that adding new links may not only promote but also destroy synchrony and link this counter-intuitive phenomenon to Braess's paradox known for traffic networks. We analytically uncover its underlying mechanism in an elementary grid example, trace its origin to geometric frustration in phase oscillators, and show that it generically occurs across a wide range of systems. As an important consequence, upgrading the grid requires particular care when adding new connections because some may destabilize the synchronization of the grid—and thus induce power outages.

  20. Incorporating outage management principles into the advanced light water reactor

    International Nuclear Information System (INIS)

    In the United States there are 110 light water reactor (LWR) plants currently in operation, with a total generating capacity of 102 580 MW(electric). These plants include 37 boiling water reactor (BWR) and 73 pressurized water reactor (PWR) units. Since 1980, more than 40 nuclear power plants have entered service in the United States. However, no new plants have been ordered by utilities and owners groups since 1978. There will come a time in the not-too-distant future that new, large electricity generating units will be needed to supply expected increases in base-load capacity. Will the new advanced LWR (ALWR) designs be able to pass muster and be chosen to help meet that need? With outage management at operating plants improving every year, what can the ALWR designs offer that has not already been incorporated?

  1. Operating plant scorecard: A statistical analysis of plant outage performance

    International Nuclear Information System (INIS)

    The purpose of this paper is to examine the relationship between outage maintenance practices and overall plant performance at domestic nuclear stations with Westinghouse nuclear steam supply systems. While the specific data in this paper reflect only the Westinghouse subset of US nuclear stations, the author feels that the conclusions reached may well be applicable to light water reactor (LWR) systems in general. The trend toward longer fuel cycles at domestic nuclear stations is inevitable from the standpoint of fuel economics and spent-fuel storage considerations. The challenge is to adjust not only maintenance practices but maintenance philosophy as well, so that longer cycle times are not achieved at the expense of unit availability

  2. Seasonal and Local Characteristics of Lightning Outages of Power Distribution Lines in Hokuriku Area

    Science.gov (United States)

    Sugimoto, Hitoshi; Shimasaki, Katsuhiko

    The proportion of the lightning outages in all outages on Japanese 6.6kV distribution lines is high with approximately 20 percent, and then lightning protections are very important for supply reliability of 6.6kV lines. It is effective for the lightning performance to apply countermeasures in order of the area where a large number of the lightning outages occur. Winter lightning occurs in Hokuriku area, therefore it is also important to understand the seasonal characteristics of the lightning outages. In summer 70 percent of the lightning outages on distribution lines in Hokuriku area were due to sparkover, such as power wire breakings and failures of pole-mounted transformers. However, in winter almost half of lightning-damaged equipments were surge arrester failures. The number of the lightning outages per lightning strokes detected by the lightning location system (LLS) in winter was 4.4 times larger than that in summer. The authors have presumed the occurrence of lightning outages from lightning stroke density, 50% value of lightning current and installation rate of lightning protection equipments and overhead ground wire by multiple regression analysis. The presumed results suggest the local difference in the lightning outages.

  3. Use of collaboration software to improve nuclear power plant outage management

    Energy Technology Data Exchange (ETDEWEB)

    Germain, Shawn

    2015-02-01

    Nuclear Power Plant (NPP) refueling outages create some of the most challenging activities the utilities face in both tracking and coordinating thousands of activities in a short period of time. Other challenges, including nuclear safety concerns arising from atypical system configurations and resource allocation issues, can create delays and schedule overruns, driving up outage costs. Today the majority of the outage communication is done using processes that do not take advantage of advances in modern technologies that enable enhanced communication, collaboration and information sharing. Some of the common practices include: runners that deliver paper-based requests for approval, radios, telephones, desktop computers, daily schedule printouts, and static whiteboards that are used to display information. Many gains have been made to reduce the challenges facing outage coordinators; however; new opportunities can be realized by utilizing modern technological advancements in communication and information tools that can enhance the collective situational awareness of plant personnel leading to improved decision-making. Ongoing research as part of the Light Water Reactor Sustainability Program (LWRS) has been targeting NPP outage improvement. As part of this research, various applications of collaborative software have been demonstrated through pilot project utility partnerships. Collaboration software can be utilized as part of the larger concept of Computer-Supported Cooperative Work (CSCW). Collaborative software can be used for emergent issue resolution, Outage Control Center (OCC) displays, and schedule monitoring. Use of collaboration software enables outage staff and subject matter experts (SMEs) to view and update critical outage information from any location on site or off.

  4. 77 FR 63757 - Extension of the Commission's Rules Regarding Outage Reporting to Interconnected Voice Over...

    Science.gov (United States)

    2012-10-17

    ..., regarding Interconnected Voice over Internet Protocol (VoIP) outage reporting rules, published at 77 FR..., and 4.9 published at 77 FR 25088, April 27, 2012, are effective December 16, 2012. FOR FURTHER... COMMISSION 47 CFR Part 4 Extension of the Commission's Rules Regarding Outage Reporting to...

  5. Operation risk analysis and control during ten-year outage program

    International Nuclear Information System (INIS)

    In L101 outage of Ling'ao nuclear power station (the 1st outage on unit 1), containment pressurizing test had been implemented. In L201 outage (the 1st outage on unit 2), primary hydraulic test, pressure vessel in-service inspection and containment pressurizing test were all done, which is the first time for Daya Bay NPS and Ling'ao NPS to complete the characteristic ten-year outage program. It is also the first time for domestic commercial nuclear power station to perform primary hydraulic test. Operations branch studied into the test requirements and possible risks so as to effectively control the operational activities and test during these programs. A complete set of overall operating procedure for ten-year outage programs has been prepared. Operating procedure as the guideline, main blocking, TSD, TCA and permit management are all helpful in the risk control. The interface problem among different test configuration and unit start-up are solved, laying a solid foundation for the success of ten-year outage program. the effectiveness and scientificity of the procedure has been proved in the outage. The success may serve as the valuable reference for two plants and domestic nuclear stations in the future. (authors)

  6. On Error Estimation in terms of Outage for Rician/Rayleigh Fading Environment

    OpenAIRE

    Anjana Shukla Dr. Vineeta Saxena Nigam

    2011-01-01

    In this paper proposes a novel mathematical method to express the outage probability for a desired radio signal received from a mobile transmitter in the presence of multipath interfering signals with rician and Rayleigh fading. New Rician/Rayleigh outage probabilities curves against the normalized reuse distance without lognormal shadowing effect are presented and discussed. The effect of SIR, Protection ratio

  7. Outage probability of opportunistic decode-and-forward relaying over Nakagami-m fading channels

    Institute of Scientific and Technical Information of China (English)

    CHUAI Gang; ZHANG Bao-zhi; LIU Xing-mei; GAO Li

    2009-01-01

    In this article, the outage probability behavior of a relay network over Nakagami-m fading channels is analyzed. Both reactive and proactive opportunistic decode-and-forward (DAF) strategies are considered. The closed-form solutions to the outage probabilities on both opportunistic DAF strategies are derived. Simulation results conf'Lrrn the presented mathematical analysis.

  8. Use of collaboration software to improve nuclear power plant outage management

    International Nuclear Information System (INIS)

    Nuclear Power Plant (NPP) refueling outages create some of the most challenging activities the utilities face in both tracking and coordinating thousands of activities in a short period of time. Other challenges, including nuclear safety concerns arising from atypical system configurations and resource allocation issues, can create delays and schedule overruns, driving up outage costs. Today the majority of the outage communication is done using processes that do not take advantage of advances in modern technologies that enable enhanced communication, collaboration and information sharing. Some of the common practices include: runners that deliver paper-based requests for approval, radios, telephones, desktop computers, daily schedule printouts, and static whiteboards that are used to display information. Many gains have been made to reduce the challenges facing outage coordinators; however; new opportunities can be realized by utilizing modern technological advancements in communication and information tools that can enhance the collective situational awareness of plant personnel leading to improved decision-making. Ongoing research as part of the Light Water Reactor Sustainability Program (LWRS) has been targeting NPP outage improvement. As part of this research, various applications of collaborative software have been demonstrated through pilot project utility partnerships. Collaboration software can be utilized as part of the larger concept of Computer-Supported Cooperative Work (CSCW). Collaborative software can be used for emergent issue resolution, Outage Control Center (OCC) displays, and schedule monitoring. Use of collaboration software enables outage staff and subject matter experts (SMEs) to view and update critical outage information from any location on site or off.

  9. Underlay Cognitive Radio Systems with Improper Gaussian Signaling: Outage Performance Analysis

    KAUST Repository

    Amin, Osama

    2016-03-29

    Improper Gaussian signaling has the ability over proper (conventional) Gaussian signaling to improve the achievable rate of systems that suffer from interference. In this paper, we study the impact of using improper Gaussian signaling on the performance limits of the underlay cognitive radio system by analyzing the achievable outage probability of both the primary user (PU) and secondary user (SU). We derive the exact outage probability expression of the SU and construct upper and lower bounds of the PU outage probability which results in formulating an approximate expression of the PU outage probability. This allows us to design the SU signal by adjusting its transmitted power and the circularity coefficient to minimize the SU outage probability while maintaining a certain PU quality-of-service. Finally, we evaluate the derived expressions for both the SU and the PU and the corresponding adaptive algorithms by numerical results.

  10. Real time organizational effectiveness improvement during a nuclear plant refueling outage

    International Nuclear Information System (INIS)

    At GPU nclear there has been a growing awareness of the impact of corporate culture on organizational effectiveness. Teamwork, continuous improvement and vision have been areas of focus for the company. At the Oyster Creek nuclear plant, pre-outage teambuilding activities have been part of the program for conducting even more effective scheduled refueling outages. These activities have been on-going for the recent scheduled refueling outages. There had been, however, no specific plan or experience with real-time organizational effectiveness improvement during the course of the refueling outage. Such an activity was conducted during the refueling outage spanning late 1992 and early 1993. This paper reports on that experience. (author)

  11. The Role of Occupational Health and Safety in Complex Outage Services to NPPs

    International Nuclear Information System (INIS)

    Meeting outage schedules in NPPs which are increasingly demanding, apart from all other aspects, introduces a new perspective on occupational health and safety (OHS). Not only is the OHS a constituent part of a plant's overall outage management, it above all dictates paramount objectives to outage service providers. The paper reviews the impacts of reductions of outage durations on OHS and presents related experience of the leading Slovenian outage services provider, NUMIP d.o.o. over the last ten years. The company is now getting prepared for its 12th outage at Krsko NPP in 2010, and has not have recorded a major injury so far, even though these projects engaged over 450 people at a time on-site. To achieve such results, a lot of emphasis is being put onto OHS management prior to and during outages. A certified OHSAS 18001 system has been established and implemented to further support preparation and execution of NUMIP's outage activities at Krsko NPP, and also for other projects. An effective continuous improvement system is built into the project, providing for implementation of lessons learned from domestic and foreign plants. To illustrate the topic in more detail, a case on a Seismic protection of polar crane project is presented. It took place in the 2009 Outage and has certainly been one of the most demanding projects from the OHS point of view for NUMIP so far. The paper aims at contributing to a better understanding of the role of effective management of OHS on the side of a service provider, and, consequently, in the overall outage success of a plant.(author).

  12. Home Use Devices: How to Prepare for and Handle Power Outages for Medical Devices That Require Electricity

    Science.gov (United States)

    ... to Prepare for and Handle Power Outages for Medical Devices that Require Electricity Center for De CDRH vices ... to Prepare for and Handle Power Outages for Medical Devices that Require Electricity As a home medical device ...

  13. Barras de FRP: avaliando o módulo de elasticidade não destrutivamente FRP bars: assesing elastic modulus nondestructively

    OpenAIRE

    Protasio F Castro

    1997-01-01

    Um estudo experimental foi realizado com o objetivo de contribuir com o desenvolvimento de métodos de ensaios de avaliação das características mecânicas das barras de plástico reforçado com fibra (FRP) a serem utilizadas como armadura nas obras de engenharia civil. Comparou-se o módulo de elasticidade estático, obtido por ensaio de tração em uma máquina universal, com o módulo de elasticidade dinâmico, obtido por ensaios não destrutivos. O módulo de elasticidade dinâmico foi determinado utili...

  14. Mass optimization of a small pressure vessel using metal/FRP (fiber reinforced polymers) hybrid structures

    International Nuclear Information System (INIS)

    In hybrid pressure vessels, composite (Fiber) is wound over a metallic liner (Steel/Aluminum) in hoop direction. In this concept of hybrid pressure vessel structure, metallic liner takes all the axial loads and fiber reinforced polymers (FRP/sub s/) takes load in circumferential (Hoop) direction. Hybrid structures combine the relatively high shear stiffness and ductility of metal alloy with high specific stiffness, strength and fatigue properties of FRP/sub s/. The relatively simple methods for producing hybrid structures circumvent the need for the complex and expensive equipment that is used for advanced composites processing. This paper presents an efficient way of designing a hybrid pressure vessel where prime concern is weight reduction over an equivalent aluminum structure and investigates various methodologies regarding combinations of metals and FRP/sub s/ for optimization of a given pressure vessel. For this purpose we adopted two different methods of simulation one is computer simulation using ANSYS and other is experimental verification by hydrostatic testing of manufactured pressure vessel. Two different pressure vessels one with aluminum liner and other with steel liner were fabricated. Kevlar 49/epoxy was wrapped around the liners in hoop direction. Both the pressure vessels were put into hydrostatic test. Strains were measured during the test and then converted into corresponding stresses. Results of hydrostatic test were quite in favor of the ANSYS results. In this way we have successfully designed, manufactured and tested the Hybrid pressure vessel saving almost 40% weight in case of aluminum liner and 43.6% in case of steel liner. (author)

  15. Vaccine potential of meningococcal FrpB: studies on surface exposure and functional attributes of common epitopes.

    Science.gov (United States)

    Ala'Aldeen, D A; Davies, H A; Borriello, S P

    1994-05-01

    Neisseria meningitidis expresses several novel outer membrane proteins (OMPs) in vivo and when grown under iron limitation in vitro. One of the most prominent is a 70 kDa iron-regulated protein (FrpB). FrpB was purified by elution from SDS-polyacrylamide gels and rabbit polyclonal antiserum (R-70) was raised against it. R-70 was bactericidal against homologous, but not heterologous, strains in the presence of human complement. The bactericidal activity was retained when R-70 was adsorbed with formaldehyde-fixed iron-replete cells (i.e. not expressing FrpB), but lost when absorbed with fixed iron-restricted cells (which express FrpB). A murine monoclonal anti-FrpB antibody (mAb M70) was raised against a common epitope which showed complete cross-reaction on Western blots of OMPs from other serogroups and serotypes of N. meningitidis and some commensal Neisseriae species. However, it failed to kill the organism. Immunogold electron microscopy on ultrathin sections, using the R-70 antiserum adsorbed with fixed iron-replete cells, showed labelling on 40% of the cells, whereas the R-70 adsorbed with fixed iron-restricted cells and mAb M70 failed to label. However, none of these sera labelled whole cells, suggesting lack of surface accessibility. It appears that the highly conserved cross-reactive epitopes of FrpB only become exposed in the process of generating the antigen, whereas the surface-exposed epitopes recognized in killing assays are immunologically variable among different strains.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7518627

  16. Power Outages, Extreme Events and Health: a Systematic Review of the Literature from 2011-2012

    Science.gov (United States)

    Klinger, Chaamala; Landeg, Owen; Murray, Virginia

    2014-01-01

    Background Extreme events (e.g. flooding) threaten critical infrastructure including power supplies. Many interlinked systems in the modern world depend on a reliable power supply to function effectively. The health sector is no exception, but the impact of power outages on health is poorly understood. Greater understanding is essential so that adverse health impacts can be prevented and/or mitigated. Methods We searched Medline, CINAHL and Scopus for papers about the health impacts of power outages during extreme events published in 2011-2012. A thematic analysis was undertaken on the extracted information. The Public Health England Extreme Events Bulletins between 01/01/2013 - 31/03/2013 were used to identify extreme events that led to power outages during this three-month period. Results We identified 20 relevant articles. Power outages were found to impact health at many levels within diverse settings. Recurrent themes included the difficulties of accessing healthcare, maintaining frontline services and the challenges of community healthcare. We identified 52 power outages in 19 countries that were the direct consequence of extreme events during the first three months of 2013. Conclusions To our knowledge, this is the first review of the health impacts of power outages. We found the current evidence and knowledge base to be poor. With scientific consensus predicting an increase in the frequency and magnitude of extreme events due to climate change, the gaps in knowledge need to be addressed in order to mitigate the impact of power outages on global health. PMID:24459613

  17. Reliabilty worth: Development of a relationship with outage magnitude, duration and frequency

    International Nuclear Information System (INIS)

    British Columbia Hydro's Worth Project Team was founded to determine values for reliability for reference in evaluation of investment and operating decisions. Work to date has produced key preliminary values for specific outages and concepts for the shape of the relationship between value and these determinates of reliability worth, frequency, magnitude and duration. These values and concepts are described. The values are developed through an iterative, trial and refinement approach. The approach incorporates direct input from customers, common sense and judgement, and micro- and macro-economic concepts. Reliability worth values for reduced or prevented outages are presented for residential, commercial, small industrial and mixed sectors and various outage durations. Reliability worth values were obtained through customer surveys. Limitations of the reliability worth value are numerous and are listed. Study of cost vs magnitude of interruption using microeconomic models has shown that costly system improvements to reduce the possibility of widespread outages may not be justified. The case of exceptionally large area outages (blackouts) is examined. The cost vs frequency relationship was examined in terms of the economic concept of utility or satisfaction. Different loss/frequency characteristics are demonstrated for different customer classes. Customer value for reduced outage duration is expressed in a curve with flatter slope than that for eliminated outages. 2 refs., 6 figs

  18. Strengthening of reinforced concrete beams with basalt-based FRP sheets: An analytical assessment

    Science.gov (United States)

    Nerilli, Francesca; Vairo, Giuseppe

    2016-06-01

    In this paper the effectiveness of the flexural strengthening of RC beams through basalt fiber-reinforced sheets is investigated. The non-linear flexural response of RC beams strengthened with FRP composites applied at the traction side is described via an analytical formulation. Validation results and some comparative analyses confirm soundness and consistency of the proposed approach, and highlight the good mechanical performances (in terms of strength and ductility enhancement of the beam) produced by basalt-based reinforcements in comparison with traditional glass or carbon FRPs.

  19. Modelling Static and Dynamic FRP-Concrete Bond Behaviour Using a Local Concrete Damage Model

    OpenAIRE

    Li, Xiaoqin; Chen, Jian-Fei; Lu, Yong; Yang, Zhenjun

    2015-01-01

    This paper presents a study on the bond behaviour of FRP-concrete bonded joints under static and dynamic loadings, by developing a meso-scale finite element model using the K&C concrete damage model in LS-DYNA. A significant number of single shear experiments under static pull-off loading were modelled with an extensive parametric study covering key factors in the K&C model, including the crack band width, the compressive fracture energy and the shear dilatation factor. It is demonstr...

  20. Use of a Computerized Tool (ORAM) to Help Manage Outage Safety and Risk at NPP Krsko

    International Nuclear Information System (INIS)

    Outage Risk Assessment and Management (ORAM) is a computerized methodology developed by the U.S. Electric Power Research Institute (EPRI) to help Nuclear Power Plant personnel manage the risk and safety associated with refueling and forced plant outages. Today, over 60 plants including NPP Krsko are using ORAM during the preparation and performance of plant outages. In fact, many plants are attributing much of the reductions in the duration of refueling outages to the use of ORAM. The success of the ORAM methodology is the capability to provide plant and management personnel with understandable results from both deterministic evaluations of plant safety and quantitative risk assessments. The Nuklearna Elektrarna Krsko (NEK) use of ORAM involves both of these approaches. The deterministic portion of ORAM is used to model the NPP Krsko Shutdown Technical Specifications and administrative considerations. The probabilistic portion of ORAM uses industry and NEK specific initiating events and other risk elements pertaining to shutdown to derive a quantitative risk assessment for various end states, including core damage and RCS boiling. This paper expands on the value of each approach and demonstrates the benefits of combining these elements in the decision-making process. Another key advantage of ORAM is the ability to apply the methodology to specific outages. Since no outage is identical, this provides tremendous benefits to plant personnel for managing the safety and risk of a particular outage. ORAM does this ba organizing all of the various plant configurations and equipment unavailability windows into numerous plant states. Furthermore, ORAM evaluations can be automatedby interfacing with outage scheduling software programs such as Primavera. For each plant state, the deterministic and the probabilistic logic evaluations are applied. This paper will demonstrate the ORAM evaluation for an actual NPP Krsko outage. (author)

  1. Application of PZT and FBG impedance sensors for structural health monitoring of reinforced concrete beams strengthened with FRP composite materials

    OpenAIRE

    Sevillano Bravo, Enrique

    2015-01-01

    Esta Tesis tiene como objetivo principal el desarrollo de métodos de identificación del daño que sean robustos y fiables, enfocados a sistemas estructurales experimentales, fundamentalmente a las estructuras de hormigón armado reforzadas externamente con bandas fibras de polímeros reforzados (FRP). El modo de fallo de este tipo de sistema estructural es crítico, pues generalmente es debido a un despegue repentino y frágil de la banda del refuerzo FRP originado en grietas intermedias causadas ...

  2. Configuration control during plant outages. A review of operating experience

    International Nuclear Information System (INIS)

    After the occurrence of several significant events in nuclear power plants during shut-down modes of operation in the eighties, and from the results of probabilistic safety assessments completed in the nineties, it was clear that risk from low power and shutdown operational modes could not be neglected and had to be addressed by appropriate safety programs. A comprehensive review of operating experience from the last ten years has been conducted by the Joint Research Centre with the objective of deriving lessons learned and recommendations useful for nuclear regulatory bodies and utilities alike. This paper is focused on one particular challenge that any nuclear plant faces whenever it plans its next outage period: how to manage the configuration of all systems under a complex environment involving numerous concurrent activities, and how to make sure that systems are returned to their valid configuration before the plant resumes power operation. This study highlights the importance of conveying accurate but synthesized information on the status of the plant to the operators in the main control room. Many of the lessons learned are related to the alarm display in the control room and to the use of check lists to control the status of systems. Members of the industry and safety authorities may now use these recommendations and lessons learned to feed their own operating experience feedback programs, and check their applicability for specific sites.

  3. OPG's approach of crediting natural circulation in outage heat sinks

    International Nuclear Information System (INIS)

    A review of crediting natural circulation as a backup means of removing the reactor core decay heat during an outage in Ontario Power Generation's nuclear stations was completed in 2000. The objective was to define the configurations and conditions under which natural circulation can be confidently credited as an effective heat transport mechanism for use in shutdown heat sink management. The project was an interdisciplinary program, and involved analyses in the areas of heat transport system thermalhydaulics, fuel and fuel channel thermal and mechanical behaviour, radiation physics, and probabilistic risks. The assessment shows that it is economically acceptable to credit natural circulation as a backup means of removing the core decay heat whenever the no fuel failure criteria are met. The economic risks associated with such a potential use decrease with time after shutdown. The waiting times after shutdown when there would be various levels of risks of damaging the pressure tubes and fuel bundles were derived for use in planning maintenance activities so as to minimize the economic risks. (author)

  4. Configuration control during plant outages. A review of operating experience

    Energy Technology Data Exchange (ETDEWEB)

    Peinador Veira, Miguel; El Kanbi, Semir [European Commission Joint Research Centre, Petten (Netherlands). Inst. for Energy and Transport; Stephan, Jean-Luc [Institut de Radioprotection et de Surete Nucleaire (IRSN), Fontenay-aux-Roses (France); Martens, Johannes [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Koeln (Germany)

    2015-03-15

    After the occurrence of several significant events in nuclear power plants during shut-down modes of operation in the eighties, and from the results of probabilistic safety assessments completed in the nineties, it was clear that risk from low power and shutdown operational modes could not be neglected and had to be addressed by appropriate safety programs. A comprehensive review of operating experience from the last ten years has been conducted by the Joint Research Centre with the objective of deriving lessons learned and recommendations useful for nuclear regulatory bodies and utilities alike. This paper is focused on one particular challenge that any nuclear plant faces whenever it plans its next outage period: how to manage the configuration of all systems under a complex environment involving numerous concurrent activities, and how to make sure that systems are returned to their valid configuration before the plant resumes power operation. This study highlights the importance of conveying accurate but synthesized information on the status of the plant to the operators in the main control room. Many of the lessons learned are related to the alarm display in the control room and to the use of check lists to control the status of systems. Members of the industry and safety authorities may now use these recommendations and lessons learned to feed their own operating experience feedback programs, and check their applicability for specific sites.

  5. Investigation of Suitability of Cascading Outage Assessment Methods for Real-Time Assessment

    DEFF Research Database (Denmark)

    Petersen, Pauli Fríðheim; Jóhannsson, Hjörtur; Nielsen, Arne Hejde

    This paper investigates the suitability of assessment methods for cascading outages for real-time assessment. A total of ten assessment methods for cascading outages are investigated, and for all of the investigated methods a complexity assessment is performed to assess the suitability...... of the method to real-time assessment. The investigation revealed that two of the methods are of special interest for further study on real-time assessment of cascading outages. These are the betweenness centrality model, based on network topology, and the manchester model, based on AC power flow....

  6. A phenomenological intra-laminar plasticity model for FRP composite materials

    Science.gov (United States)

    Zhou, Yinhua; Hou, Chi; Wang, Wenzhi; Zhao, Meiying; Wan, Xiaopeng

    2015-07-01

    The nonlinearity of fibre-reinforced polymer (FRP) composites have significant effects on the analysis of composite structures. This article proposes a phenomenological intralaminar plasticity model to represent the nonlinearity of FRP composite materials. Based on the model presented by Ladeveze et al., the plastic potential and hardening functions are improved to give a more rational description of phenomenological nonlinearity behavior. A four-parameter hardening model is built to capture important features of the hardening curve and consequently gives the good matching of the experiments. Within the frame of plasticity theory, the detailed constitutive model, the numerical algorithm and the derivation of the tangent stiffness matrix are presented in this study to improve model robustness. This phenomenological model achieved excellent agreement between the experimental and simulation results in element scale respectively for glass fibre-reinforced polymer (GFRP) and carbon fibre-reinforced polymer (CFRP). Moreover, the model is capable of simulating the nonlinear phenomenon of laminates, and good agreement is achieved in nearly all cases.

  7. Influence of terahertz waves on the penetration in thick FRP composite materials

    Science.gov (United States)

    Im, Kwang-Hee; Hsu, David K.; Chiou, Chien-Ping; Barnard, Daniel J.; Yang, In-Young; Park, Je-Woong

    2014-02-01

    Fiber reinforced plastics (FRP) are increasingly utilized in engineering structures because of their performance and fabrication advantages. With this increased utilization, a technique to gage quality and further characterize the materials would be beneficial. The nondestructive applications for Terahertz (T-ray) methods have also experienced increased utilization for evaluating engineering materials and will be reported on here in applications for the inspection and characterization of FRP materials used in wind energy components. First, refraction and transmission T-ray modes are used to determine the refractive index (n) of a glass fiber reinforced plastic (GFRP) reference sample, and extended for calculating the refractive indices for a sample of GFRP, balsa and epoxy. Additionally, carbon fiber reinforced plastic (CFRP) samples were evaluated with respect to fiber directions versus T-ray electric field polarization direction to evaluate the level of penetration of T-ray energy due to the fiber orientation dependent conductivity of this composite material. Finally, an evaluation of T-ray data was made to evaluate resonance effects, where the resonance frequency was found to agree with that expected from reflections from individual plies in thick GFRP laminates.

  8. ANALISA TEKNIS DAN EKONOMIS PENGGUNAAN COREMAT UNTUK KONSTRUKSI FRP (FIBERGLASS REINFORCED PLASTIC SANDWICH PADA BADAN KAPAL

    Directory of Open Access Journals (Sweden)

    Parlindungan Manik

    2012-04-01

    Full Text Available Planning of ship construction is make its having good effectivity value and efficiency. Composite as material alternative to changes of steel feedstock and wood has many applied named FRP (fiberglass reinforced plastics single skin. The weakness of this FRP was heavy construction and requires many production time. Therefore, will be checked comparison between single skin with sandwich constructions for shell. In this research, the way for making composite is hand lay up method with three various thickness of skin there are : t, t/2, and t/4. To know strength comparison from the various skin of sandwich with single skin, must be test, consist of tensile test.. The result is analyzed then compared by BKI (Biro Klasifikasi Indonesia rules for the fiberglass ship. Based on the result, indicates that optimization skin thickness of sandwich construction applies Coremat which tensile strength it is equivalent with Single Skin at 2/3t and usage of Sandwich construction causes 23,12 % lighter. In economic analyze, advantage from low weight is compensation of addition 23,12 % DWT. Material cost for Sandwich about 11,35% bigger than Single Skin construction.

  9. Deformation behavior of FRP-metal composites locally reinforced with carbon fibers

    Science.gov (United States)

    Scholze, M.; Kolonko, A.; Lindner, T.; Lampke, T.; Helbig, F.

    2016-03-01

    This study investigates variations of hybrid laminates, consisting of one aluminum sheet and a unidirectional glass fiber (GF) reinforced polyamide 6 (PA6) basic structure with partial carbon fiber (CF) reinforcement. To create these heterogeneous FRP laminates, it is necessary to design and produce semi-finished textile-based products. Moreover, a warp knitting machine in conjunction with a warp thread offset unit was used to generate bionic inspired compounds. By the variation of stacking prior to the consolidation process of the hybrid laminate, an oriented CF reinforcement at the top and middle layer of the FRP is realized. In both cases the GFRP layer prevents contact between the aluminum and carbon fibers. In so doing, the high strength of carbon fibers can be transferred to the hybrid laminate in load directions with an active prevention of contact corrosion. The interface strength between thermoplastic and metal component was improved by a thermal spray coating on the aluminum sheet. Because of the high surface roughness and porosity, mechanical interlock was used to provide high interface strength without bonding agents between both components. The resulting mechanical properties of the hybrid laminates are evaluated by three point bending tests in different load directions. The effect of local fiber orientation and layer positioning on failure and deformation mechanism is additionally investigated by digital image correlation (DIC).

  10. ANALISA TEKNIS DAN EKONOMIS PENGGUNAAN COREMAT UNTUK KONSTRUKSI FRP (FIBERGLASS REINFORCED PLASTIC SANDWICH PADA BADAN KAPAL

    Directory of Open Access Journals (Sweden)

    Parlindungan Manik

    2012-02-01

    Full Text Available Planning of ship construction is make its having good effectivity value and efficiency. Composite as materialalternative to changes of steel feedstock and wood has many applied named FRP (fiberglass reinforcedplastics single skin. The weakness of this FRP was heavy construction and requires many production time.Therefore, will be checked comparison between single skin with sandwich constructions for shell.In this research, the way for making composite is hand lay up method with three various thickness of skinthere are : t, t/2, and t/4. To know strength comparison from the various skin of sandwich with single skin,must be test, consist of tensile test.. The result is analyzed then compared by BKI (Biro Klasifikasi Indonesiarules for the fiberglass ship.Based on the result, indicates that optimization skin thickness of sandwich construction applies Corematwhich tensile strength it is equivalent with Single Skin at 2/3t and usage of Sandwich construction causes23,12 % lighter. In economic analyze, advantage from low weight is compensation of addition 23,12 % DWT.Material cost for Sandwich about 11,35% bigger than Single Skin construction.

  11. Nonlinear FE simulations of structural behavior parameters of reinforced concrete beam with epoxy-bonded FRP

    Science.gov (United States)

    Sasmal, Saptarshi; Kalidoss, S.

    2015-05-01

    In the present study, investigations on fiber-reinforced plastic (FRP) plated-reinforced concrete (RC) beam are carried out. Numerical investigations are performed by using a nonlinear finite element analysis by incorporating cracking and crushing of concrete. The numerical models developed in the present study are validated with the results obtained from the experiment under monotonic load using the servo-hydraulic actuator in displacement control mode. Further, the validated numerical models are used to evaluate the influence of different parameters. It is found from the investigations that increase in the elastic modulus of adhesive layer and CFRP laminate increases the interfacial stresses whereas increase in laminate modulus decreases the displacement and reinforcement strain of the beam. It is also observed that increase in the adhesive layer can largely reduce the interfacial stresses, whereas increase in laminate thickness increases it. However, increase in laminate thickness decreases the displacement and reinforcement strain of the beam significantly. It is mention worthy that increase in laminate length reduces the interfacial stresses, whereas CFRP width change does not affect the interfacial stresses. The study will be useful for the design and practicing engineers for arriving at the FRP-based strengthening schemes for RC structures judiciously.

  12. Commercial operation and outage experience of ABWR at Kashiwazaki-Kariwa units Nos. 6 and 7

    International Nuclear Information System (INIS)

    Kashiwazaki-Kariwa Nuclear Power Station Units Nos. 6 and 7, the world's first ABWRs (Advanced Boiling Water Reactor), started commercial operation on November 7, 1996 and July 2, 1997, respectively, and continued their commercial operation with a high capacity factor, low occupational radiation exposure and radioactive waste. Units 6 and 7 were in their 3rd cycle operation until 25th April 1999 and 1st November 1999, respectively. Thermal efficiency was 35.4-35.8% (design thermal efficiency: 34.5%) during these period, demonstrating better performance than that of BWR-5 (design thermal efficiency: 33.4%). Nos. 6 and 7 have experienced 2 annual outages. The first outage of unit No. 6 started on November 20, 1997 and was completed within 61 days (including 6 New Year holidays), and the second outage started on March 13, 1999 and was completed within 44 days. The first annual outage of unit No. 7 started on May 27, 1998, earlier than it would normally have been, to avoid an annual outage during the summer, and was completed within 55 days, and the second outage started on September 18th, 1999 and was completed within 45 days, All annual outages were carried out within a very short time period without any severe malfunctions, including newly designed ABWR systems and equipment. As the first outage in Japan, 55 days is a very short period, despite the fact that the Nos. 6 and 7 are the first ABWRs in the world and the largest capacity units in Japan. The total occupational radiation exposure of No. 6 was 300 man-mSv (1st outage) and 331 man-mSv (2nd outage). That of Unit 7 was 153 man-mSv (1st outage) Those of unit No. 6 were at the same level as those of unit No. 3, which is the latest design 1100MW(e) BWR-5. That of unit No. 7 was the lowest ever at Kashiwazaki-Kariwa nuclear power station. The drums of radioactive waste discharged during the annual outage numbered 54 (1st outage) for No. 6 and 62 (1st outage) for No. 7, which was less than the design target of 100

  13. Extreme Outages due to Polarization Mode Dispersion Periodic and Quasi-Periodic Compensation Strategies

    CERN Document Server

    Chernyak, V; Kolokolov, I V; Lebedev, V; Chernyak, Vladimir; Chertkov, Michael; Kolokolov, Igor; Lebedev, Vladimir

    2003-01-01

    Effect of birefringent disorder on the Bit Error Rate (BER) in an optical fiber system subject to amplifier noise may lead to extreme outages, related to anomalously large values of BER. We analyze the Probability Distribution Function (PDF) of BER for various strategies of Polarization Mode Dispersion (PMD) compensation. A compensation method capable of more efficient suppression of the extreme outages, and thus of an essential enhancement of the fiber system performance, is proposed.

  14. The impact of fuel cladding failure events on occupational radiation exposures at nuclear power plants: Case study, PWR [pressurized-water reactor] during an outage

    International Nuclear Information System (INIS)

    This report is the second in a series of case studies designed to evaluate the magnitude of increase in occupational radiation exposures at commercial US nuclear power plants resulting from small incidents or abnormal events. The event evaluated is fuel cladding failure, which can result in elevated primary coolant activity and increased radiation exposure rates within a plant. For this case study, radiation measurements were made at a pressurized-water reactor (PWR) during a maintenance and refueling outage. The PWR had been operating for 22 months with fuel cladding failure characterized as 105 pin-hole leakers, the equivalent of 0.21% failed fuel. Gamma spectroscopy measurements, radiation exposure rate determinations, thermoluminescent dosimeter (TLD) assessments, and air sample analyses were made in the plant's radwaste, pipe penetration, and containment buildings. Based on the data collected, evaluations indicate that the relative contributions of activation products and fission products to the total exposure rates were constant over the duration of the outage. This constancy is due to the significant contribution from the longer-lived isotopes of cesium (a fission product) and cobalt (an activation product). For this reason, fuel cladding failure events remain as significant to occupational radiation exposure during an outage as during routine operations. As documented in the previous case study (NUREG/CR-4485 Vol. 1), fuel cladding failure events increased radiation exposure rates an estimated 540% at some locations of the plant during routine operations. Consequently, such events can result in significantly greater radiation exposure rates in many areas of the plant during the maintenance and refueling outages than would have been present under normal fuel conditions

  15. NMR assignment of intrinsically disordered self-processing module of the FrpC protein of Neisseria meningitidis

    Czech Academy of Sciences Publication Activity Database

    Kubáň, V.; Nováček, J.; Bumba, Ladislav; Žídek, L.

    2015-01-01

    Roč. 9, č. 2 (2015), s. 435-440. ISSN 1874-2718 R&D Projects: GA ČR(CZ) GAP207/11/0717 Institutional support: RVO:61388971 Keywords : FrpC * Self-processing module * Neisseria meningitidis Subject RIV: EE - Microbiology, Virology Impact factor: 0.760, year: 2014

  16. A Design-Oriented Combined Model (7 MPa to 190 MPa for FRP-Confined Circular Short Columns

    Directory of Open Access Journals (Sweden)

    Zehra Canan Girgin

    2015-09-01

    Full Text Available This study addresses a design oriented combined model to predict the ultimate strengths and ultimate strains in an extensive range of unconfined strength (7 to 190 MPa for the axially loaded fiber-reinforced polymer (FRP-wrapped circular short columns. Modified Hoek-Brown strength criterion, which was previously extended to FRP-confined concrete from 7 to 108 MPa, is revisited and verified. An empirical strength model beyond 108 MPa encompassing ultra-high strength concrete (UHSC and ultra-high performance concrete (UHPC data, as well as empirical strain models, are defined to accomplish the design oriented combined model. This article especially focuses on the verification of the proposed strain models. The assessment performances of those models for carbon FRP (CFRP and glass FRP (GFRP confinement are compared with specific models in the current literature. Strength and strain predictions for UHSC and UHPC are integrated into the design oriented combined model as well. The assessments on this model agree with the experimental results in high accuracy.

  17. Outage Analysis of Spectrum-Sharing over M-Block Fading with Sensing Information

    KAUST Repository

    Alabbasi, Abdulrahman

    2016-07-13

    Future wireless technologies, such as, 5G, are expected to support real-time applications with high data throughput, e.g., holographic meetings. From a bandwidth perspective, cognitive radio is a promising technology to enhance the system’s throughput via sharing the licensed spectrum. From a delay perspective, it is well known that increasing the number of decoding blocks will improve the system robustness against errors, while increasing the delay. Therefore, optimally allocating the resources to determine the tradeoff of tuning the length of decoding blocks while sharing the spectrum is a critical challenge for future wireless systems. In this work, we minimize the targeted outage probability over the block-fading channels while utilizing the spectrum-sharing concept. The secondary user’s outage region and the corresponding optimal power are derived, over twoblocks and M-blocks fading channels. We propose two suboptimal power strategies and derive the associated asymptotic lower and upper bounds on the outage probability with tractable expressions. These bounds allow us to derive the exact diversity order of the secondary user’s outage probability. To further enhance the system’s performance, we also investigate the impact of including the sensing information on the outage problem. The outage problem is then solved via proposing an alternating optimization algorithm, which utilizes the verified strict quasiconvex structure of the problem. Selected numerical results are presented to characterize the system’s behavior and show the improvements of several sharing concepts.

  18. The strategy of reducing the annual outage length of Fukushima-II NPS

    International Nuclear Information System (INIS)

    The ninth annual outage inspection of Fukushima-II NPS unit No.3 was executed within 36 days from September 12 to October 17, 1998. The outage length of 36 days is the shortest in our history. The capacity factor will exceed 86% in fiscal 1998. It used to be emphasized the necessity for energy security and safety rather than costs in the nuclear industry. Recently, environment of the electric industry has been becoming more competitive. The nuclear industry had to participate in the competition. The preparations for shortening the annual outage length were begun in 1994. The shortening activities have progressed with the policy which ensure safety and reliability. The outage length has been reduced from mid-80 s to 36 days step by step over 3 years. The most important factor in shortening the outage length is to commit all participants, employees and contractors. Because of the endeavor to shorten the outage length, the capacity factor of Fukushima-II NPS is being maintained at a higher level. Hereafter the capacity factor level of 85% will continue, except unplanned shutdown. (author)

  19. OTRA-THS MAC to reduce Power Outage Data Collection Latency in a smart meter network

    Energy Technology Data Exchange (ETDEWEB)

    Garlapati, Shravan K [ORNL; Kuruganti, Phani Teja [ORNL; Buehrer, Richard M [ORNL; Reed, Jeffrey H [ORNL

    2014-01-01

    The deployment of advanced metering infrastructure by the electric utilities poses unique communication challenges, particularly as the number of meters per aggregator increases. During a power outage, a smart meter tries to report it instantaneously to the electric utility. In a densely populated residential/industrial locality, it is possible that a large number of smart meters simultaneously try to get access to the communication network to report the power outage. If the number of smart meters is very high of the order of tens of thousands (metropolitan areas), the power outage data flooding can lead to Random Access CHannel (RACH) congestion. Several utilities are considering the use of cellular network for smart meter communications. In 3G/4G cellular networks, RACH congestion not only leads to collisions, retransmissions and increased RACH delays, but also has the potential to disrupt the dedicated traffic flow by increasing the interference levels (3G CDMA). In order to overcome this problem, in this paper we propose a Time Hierarchical Scheme (THS) that reduces the intensity of power outage data flooding and power outage reporting delay by 6/7th, and 17/18th when compared to their respective values without THS. Also, we propose an Optimum Transmission Rate Adaptive (OTRA) MAC to optimize the latency in power outage data collection. The analysis and simulation results presented in this paper show that both the OTRA and THS features of the proposed MAC results in a Power Outage Data Collection Latency (PODCL) that is 1/10th of the 4G LTE PODCL.

  20. Evaluation of RC Bridge Piers Retrofitted using Fiber-Reinforced Polymer (FRP)

    International Nuclear Information System (INIS)

    For many long years, steel reinforcements have been considered as the only tool for concrete confinements and studied widely, but nowadays application of Fiber Reinforced Polymer (FRP) as an effective alternative is well appreciated. Many bridges have been constructed in the past that are necessary to be retrofitted for resisting against the earthquake motions. The objective of this research is evaluation of nonlinear behavior of RC bridge piers. Eight RC bridge piers have been modeled by ABAQUS software under micromechanical model for homogeneous anisotropic fibers. Also the Bilinear Confinement Model by Nonlinear Transition Zone of Mirmiran has been considered. Then types and angles of fibers and their effects on the final responses were evaluated. Finally, effects of retrofitting are evaluated and some suggestions presented

  1. PreFRP: Prediction and visualization of fluctuation residues in proteins

    Science.gov (United States)

    Saravanan, Konda Mani; Senthil, Renganathan

    2016-01-01

    Aim: The PreFRP web server extracts sequence and basic information of a protein structure and groups amino acid residues in a protein into three important types such as high, moderate, and weak fluctuating residues. Materials and Methods: The server takes a protein data bank file or an amino acid sequence as input and prints the probability of amino acid residues to fluctuate. The server also provides a link to Jmol, a molecular visualization program to visualize the high, moderate, and weak fluctuating residues in three different colors. Results: Prediction and visualization of fluctuating amino acid residues in proteins may help to understand the complex three-dimensional structure of proteins and may further help in docking and mutation experiments. Availability: The web server is freely accessible through the web page of the author's institution http://www.mpi.edu.in/prefrp/link.html.

  2. Influence of Basalt FRP Mesh Reinforcement on High-Performance Concrete Thin Plates at High Temperatures

    DEFF Research Database (Denmark)

    Hulin, Thomas; Lauridsen, Dan H.; Hodicky, Kamil;

    2015-01-01

    , requiring the use of steel. Microscope observations highlighted degradation of the HPC-BFRP mesh interface with temperature due to the melting polymer matrix of the mesh. These observations call for caution when using fiber-reinforced polymer (FRP) reinforcement in elements exposed to fire hazard....... furnace tests compared performances of HPC with and without BFRP mesh, assessing material behavior; another set including polypropylene (PP) fibers to avoid spalling compared the performance of BFRP mesh reinforcement to that of regular steel reinforcement, assessing mechanical properties......A basalt fiber–reinforced polymer (BFRP) mesh was introduced as reinforcement in high-performance concrete (HPC) thin plates (20–30 mm) for implementation in precast sandwich panels. An experimental program studied the BFRP mesh influence on HPC exposed to high temperature. A set of standard...

  3. An Analysis of Machining Induced Damages in FRP Composites — A Micromechanics Finite Element Approach

    Science.gov (United States)

    Nayak, D.; Singh, I.; Bhatnagar, N.; Mahajan, P.

    2004-06-01

    The machining of FRP composites has posed a serious challenge to industry and academia alike as far as the sub-surface damage is concerned caused by fiber-matrix debonding. Proper prediction of sub-surface damage is thus essential for different fiber orientations and fiber-matrix bonding. A Cohesive Zone Modeling (CZM) of the fiber-matrix debonding leading to interfacial separation is presented in this paper. The cohesive bonding strength existing between the fiber and matrix increases with increased separation, reaches a maximum value before causing permanent debonding when the cohesive strength between the interfaces vanishes. An effort is made to implement the Cohesive Zone Model (CZM) and to ascertain the extent of debonding below the trim plane at fiber failure.

  4. Creep behavior of an epoxy resin and an epoxy-based FRP in condition of simultaneous supply of radiation and stress at cryogenic temperatures

    International Nuclear Information System (INIS)

    Creep tests of an epoxy resin and an epoxy-based FRP in bending under irradiation condition have been carried out, to investigate the synergistic effects of radiation and stress on mechanical properties of FRP. Simultaneous supply of stress and irradiation on the epoxy resin and the FRP enhanced creep rates in comparison with that supply of the stress on a post-irradiated one did. ESR spectra measurement was also carried out to study the change of molecule of the resin irradiated. Increase of molecular weight between crosslinks was found out to be enhanced by the synergistic effect of radiation and stress. The mechanism of increased damage of FRP induced by the effects of simultaneous stress and irradiation is discussed. (author)

  5. International outage coding system for nuclear power plants. Results of a co-ordinated research project

    International Nuclear Information System (INIS)

    The experience obtained in each individual plant constitutes the most relevant source of information for improving its performance. However, experience of the level of the utility, country and worldwide is also extremely valuable, because there are limitations to what can be learned from in-house experience. But learning from the experience of others is admittedly difficult, if the information is not harmonized. Therefore, such systems should be standardized and applicable to all types of reactors satisfying the needs of the broad set of nuclear power plant operators worldwide and allowing experience to be shared internationally. To cope with the considerable amount of information gathered from nuclear power plants worldwide, it is necessary to codify the information facilitating the identification of causes of outages, systems or component failures. Therefore, the IAEA established a sponsored Co-ordinated Research Project (CRP) on the International Outage Coding System to develop a general, internationally applicable system of coding nuclear power plant outages, providing worldwide nuclear utilities with a standardized tool for reporting outage information. This TECDOC summarizes the results of this CRP and provides information for transformation of the historical outage data into the new coding system, taking into consideration the existing systems for coding nuclear power plant events (WANO, IAEA-IRS and IAEA PRIS) but avoiding duplication of efforts to the maximum possible extent

  6. Balance-of-plant outage availability study. Phase I. Extension report

    International Nuclear Information System (INIS)

    After completion of the Phase 1 Refueling Outage Availability Study, Babcock and Wilcox and the U.S. Department of Energy entered into a supplemental agreement to perform a balance-of-plant maintenance, inspection, and test study with the cooperation of Duke Power Company and Arkansas Power and Light Company. The objectives were (1) to expand the Phase 1 data base, including balance-of-plant activities, to reduce outage time and increase plant availability and (2) to conduct an onsite review of plant maintenance, practices to complement the utility efforts in reducing outage time and increasing on-line operational time. Data were obtained from (1) observations during the 1977 refueling outage at Oconee 3, (2) review of maintenance practices during the Arkansas Nuclear One, Unit 1, operational cycle in 1977, and (3) selected observations of the 1978 refueling outage at ANO-1. Accumulated data were then reviewed and analyzed to produce a list of improvement recommendations for Oconee 3 and ANO-1 that can be generically applied to plants of similar design and construction

  7. Detecting Power Outages with the VIIRS DNB Images - potentials and challenges

    Science.gov (United States)

    Cao, C.; Uprety, S.; Shao, X.

    2012-12-01

    Power outages after a major storm or hurricane affect millions of people. The launch of the Suomi NPP with the VIIRS significantly enhances our capability to monitor and detect power outages on a daily basis with the Day Night Band (DNB) which outperforms the traditional OSL on DMSP satellites in both spatial and radiometric resolutions. This study explores the use of the DNB for detecting power outages in the Washington DC metropolitan area in June 2012, which was the largest non-hurricane power outage in history for the region with millions of people lost power, and state of emergency declared in some states such as Virginia. The DNB data were analyzed for the period one week before and after the storm. The light loss is estimated through image differencing techniques for spatial patterns, as well as total radiance and irradiance changes as a time series. The effects of cloud absorption and scattering are evaluated using the cloud masks from VIIRS products, and the long wave thermal infrared images are also used to assist the assessment. The results show that the DNB data are very useful for both spatial and radiometric detection of light loss, but also with some challenges due to clouds and the known terminator straylight effect of the instrument for the region during summer solstice. It is expected that further refinements in the methodology will significantly reduce the uncertainties. A VIIRS Data Robotics system is also being developed which will allow the routine detection of power outages for any given location worldwide.

  8. Distributed Power-Line Outage Detection Based on Wide Area Measurement System

    Directory of Open Access Journals (Sweden)

    Liang Zhao

    2014-07-01

    Full Text Available In modern power grids, the fast and reliable detection of power-line outages is an important functionality, which prevents cascading failures and facilitates an accurate state estimation to monitor the real-time conditions of the grids. However, most of the existing approaches for outage detection suffer from two drawbacks, namely: (i high computational complexity; and (ii relying on a centralized means of implementation. The high computational complexity limits the practical usage of outage detection only for the case of single-line or double-line outages. Meanwhile, the centralized means of implementation raises security and privacy issues. Considering these drawbacks, the present paper proposes a distributed framework, which carries out in-network information processing and only shares estimates on boundaries with the neighboring control areas. This novel framework relies on a convex-relaxed formulation of the line outage detection problem and leverages the alternating direction method of multipliers (ADMM for its distributed solution. The proposed framework invokes a low computational complexity, requiring only linear and simple matrix-vector operations. We also extend this framework to incorporate the sparse property of the measurement matrix and employ the LSQRalgorithm to enable a warm start, which further accelerates the algorithm. Analysis and simulation tests validate the correctness and effectiveness of the proposed approaches.

  9. The Direct Assessment and Captive Costs Methods for Estimating the Economic Costs of Power Outages among Selected Industries in Nigeria

    Directory of Open Access Journals (Sweden)

    Hachimenum N. Amadi

    2015-05-01

    Full Text Available Due to frequent power outages, the typical Nigerian firm incurs huge costs arising from damaged equipment, lost output, spoiled materials, idle workers and restart costs. This paper developed mathematical models for the computation of the economic costs due to power outages in selected electricity intensive industries from the major industrial areas of Nigeria. This became necessary to optimize investment and operating decisions for adequate power outage mitigation measures.

  10. Status Report on the Development of Micro-Scheduling Software for the Advanced Outage Control Center Project

    Energy Technology Data Exchange (ETDEWEB)

    Shawn St. Germain; Kenneth Thomas; Ronald Farris; Jeffrey Joe

    2014-09-01

    The long-term viability of existing nuclear power plants (NPPs) in the United States (U.S.) is dependent upon a number of factors, including maintaining high capacity factors, maintaining nuclear safety, and reducing operating costs, particularly those associated with refueling outages. Refueling outages typically take 20-30 days, and for existing light water NPPs in the U.S., the reactor cannot be in operation during the outage. Furthermore, given that many NPPs generate between $1-1.5 million/day in revenue when in operation, there is considerable interest in shortening the length of refueling outages. Yet, refueling outages are highly complex operations, involving multiple concurrent and dependent activities that are difficult to coordinate. Finding ways to improve refueling outage performance while maintaining nuclear safety has proven to be difficult. The Advanced Outage Control Center project is a research and development (R&D) demonstration activity under the Light Water Reactor Sustainability (LWRS) Program. LWRS is a R&D program which works with industry R&D programs to establish technical foundations for the licensing and managing of long-term, safe, and economical operation of current NPPs. The Advanced Outage Control Center project has the goal of improving the management of commercial NPP refueling outages. To accomplish this goal, this INL R&D project is developing an advanced outage control center (OCC) that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. This report describes specific recent efforts to develop a capability called outage Micro-Scheduling. Micro-Scheduling is the ability to allocate and schedule outage support task resources on a sub-hour basis. Micro-Scheduling is the real-time fine-tuning of the outage schedule to react to the actual progress of the primary outage activities to ensure that support task resources are

  11. Outage Performance of Flexible OFDM Schemes in Packet-Switched Transmissions

    Directory of Open Access Journals (Sweden)

    Romain Couillet

    2009-01-01

    Full Text Available α-OFDM, a generalization of the OFDM modulation, is proposed. This new modulation enhances the outage capacity performance of bursty communications. The α-OFDM scheme is easily implementable as it only requires an additional time symbol rotation after the IDFT stage and a subsequent phase rotation of the cyclic prefix. The physical effect of the induced rotation is to slide the DFT window over the frequency spectrum. When successively used with different angles α at the symbol rate, α-OFDM provides frequency diversity in block fading channels. Interestingly, simulation results show a substantial gain in terms of outage capacity and outage BER in comparison with classical OFDM modulation schemes. The framework is extended to multiantenna and multicellular OFDM-based standards. Practical simulations, in the context of 3GPP-LTE, called hereafter α-LTE, sustain our theoretical claims.

  12. Outage performance of reactive cooperation in Nakagami-m fading channels

    KAUST Repository

    Benjillali, Mustapha

    2010-06-01

    In this paper, we investigate the outage performance of Decode-and-Forward with reactive relaying in dual-hop cooperetive Nakagaml-m fading links. The destination, based on the umque knowledge of local second hop channel state information, selects the best relay to increase the chances of cooperation when the direct link is also available. After deriving the exact distribution of the variables of interest, the outage probability of the system - with and without the direct link - is obtained in closed-form, and the ε-outage capacity is derived in the particular c.se wh.ere the channel model is reduced to a Rayleigh fading. Simulation results confirm the accuracy of our analysis for a large selection of system and fading parameters.

  13. A Simple Scheme for Improved Performance of Fixed Outage Rate Cellular System

    Directory of Open Access Journals (Sweden)

    Hussein M.A. Basi

    2004-01-01

    Full Text Available The traffic characteristic of mobile cellular systems is rather distinct from that of a fixed telephone network. However the system planning and design are still carried out with the tools of conventional traffic theory. In the recent days much work is being done in the performance evaluation of mobile or cellular communication systems in order to develop a system with greater efficiency. The useful parameters to estimate the performance of the system are voice quality, frequency spectrum efficiency and Grade of Service (GOS. The grade of service will be affected due to outage of channels. In this study, a new scheme is proposed to reduce lost calls due to channel outage in the fixed rate outage cellular system. In this proposed scheme the call will never dropped but may be delayed. The system performance is evaluated for different conditions and the results are discussed.

  14. Outage performance of Decode-and-Forward partial selection in Nakagami-m fading channels

    KAUST Repository

    Benjillali, Mustapha

    2010-01-01

    In this paper, we investigate the outage performance of Decode-and-Forward with partial selection relaying in dualhop cooperative Nakagami-m fading links. The source, based on the unique knowledge of local first hop channel state information, selects the best relay to increase the chances of successful decoding and hence the possibility of cooperation when the direct link is also available. After deriving the exact distribution of the sum of two gamma variates with the same shape parameter, the outage probability of the system-with and without the direct link-is obtained in closed-form. We also derive the ε-outage capacity in different particular cases, and the obtained results- when the channel model is reduced to a Rayleigh fading-are either new or correspond to those previously obtained in other works. Simulation results confirm the accuracy of our analysis for a large selection of system and fading parameters. © 2009 IEEE.

  15. Outage Performance of Decode-and-Forward in Two-Way Relaying with Outdated CSI

    KAUST Repository

    Hyadi, Amal

    2015-01-07

    In this paper, we analyze the outage behavior of decode-and-forward relaying in the context of selective two-way cooperative systems. First, a new relay selection metric is proposed to take into consideration both transmission rates and instantaneous link conditions between cooperating nodes. Afterwards, the outage probability of the proposed system is derived for Nakagami-m fading channels in the case when perfect channel state information is available and then extended to the more realistic scenario where the available channel state information (CSI) is outdated due to fast fading. New expressions for the outage probability are obtained, and the impact of imperfect CSI on the performance is evaluated. Illustrative numerical results, Monte Carlo simulations, and comparisons with similar approaches are presented to assess the accuracy of our analytical derivations and confirm the performance gain of the proposed scheme.

  16. Operational Readiness Verification, Phase 3. A Field Study at a Swedish NPP during a Productive Outage (Safety-train Outage)

    International Nuclear Information System (INIS)

    This report describes the results from Phase III of a study on Operational Readiness Verification (ORV) that was carried out from December 2002 to November 2003. The work comprised a field study of ORV activities at a Swedish NPP during a planned productive outage [subavstaellning], which allowed empirical work to be conducted in an appropriate environment with good accessibility to technical staff. One conclusion from Phase I of this project was the need to look more closely at the differences between three levels or types of tests that occur in ORV: object (component) test, system level test and (safety) function test, and to analyse the different steps of testing in order to understand the nontrivial relations between tests and safety. A second conclusion was the need to take a closer look at the organisation's ability to improvise in the sense of adjusting pre-defined plans to the actual conditions under which they are to be carried out. Phase II of the project found that although all three types of test occurred, they were rather used according to need rather than to a predefined arrangement or procedure. The complexity of ORV could be understood and described by using the concepts of Community of Practice, embedding, and Efficiency-Thoroughness Trade-Off. In addition, organisation and the different communities of practice improvise by adjusting pre-defined plans or work orders to the existing conditions. Such improvisations take place both on the levels of individual actions, on the level of communities of practice, and on the organisational level. The ability to improvise is practically a necessity for work to be carried out, but is also a potential risk. Phase III of the project studied how tasks are adapted relative to the different types of embedding and the degree of correspondence between nominal and actual ORV. It also looked further at the different Communities of Practice that are part of maintenance and ORV, focusing on the coordination and

  17. Operational Readiness Verification, Phase 3. A Field Study at a Swedish NPP during a Productive Outage (Safety-train Outage)

    Energy Technology Data Exchange (ETDEWEB)

    Hollnagel, Erik [Linkoeping Univ. (Sweden). Dept. of Computer and Information Science; Gauthereau, Vincent; Persson, Bodil [Linkoeping Univ. (Sweden). Dept. of Industrial Engineering

    2004-01-01

    This report describes the results from Phase III of a study on Operational Readiness Verification (ORV) that was carried out from December 2002 to November 2003. The work comprised a field study of ORV activities at a Swedish NPP during a planned productive outage, which allowed empirical work to be conducted in an appropriate environment with good accessibility to technical staff. One conclusion from Phase I of this project was the need to look more closely at the differences between three levels or types of tests that occur in ORV: object (component) test, system level test and (safety) function test, and to analyse the different steps of testing in order to understand the nontrivial relations between tests and safety. A second conclusion was the need to take a closer look at the organisation's ability to improvise in the sense of adjusting pre-defined plans to the actual conditions under which they are to be carried out. Phase II of the project found that although all three types of test occurred, they were rather used according to need rather than to a predefined arrangement or procedure. The complexity of ORV could be understood and described by using the concepts of Community of Practice, embedding, and Efficiency-Thoroughness Trade-Off. In addition, organisation and the different communities of practice improvise by adjusting pre-defined plans or work orders to the existing conditions. Such improvisations take place both on the levels of individual actions, on the level of communities of practice, and on the organisational level. The ability to improvise is practically a necessity for work to be carried out, but is also a potential risk. Phase III of the project studied how tasks are adapted relative to the different types of embedding and the degree of correspondence between nominal and actual ORV. It also looked further at the different Communities of Practice that are part of maintenance and ORV, focusing on the coordination and communication between

  18. Control Room Tasks During Refueling in Ringhals 1 Nuclear Power Plant - Operator performance during refuelling outages

    International Nuclear Information System (INIS)

    This paper discusses the performance and tasks of the operators in the control room during refuelling outages. Analyses of such events have, during the last years, shown that the risk for nuclear accidents is not negligible compared with the risk at higher reactor power levels. Some experts have the opinion that, due to mistakes during an outage, the risk for such accidents during the outage and other accidents later on during power operation is higher than in other plant situations. The high risk level is mainly a result of errors at maintenance actions and supervision of lining up of safety systems. Most of the control rooms in existing NPPs were designed more than 10 years ago. At that time the activities and the tasks for the operators were not very well understood. Procedures for refuelling and other activities during the outages were not described very well. Often the utility organisation for refuelling outages was not established at the start of the control room design. Experience from operation during many years has shown that the performance of operators can be improved in existing plant, and thus risks be reduced, by upgrading the control room. These issues have been studied as a part of the modernisation project for Ringhals 1, an ABB Atom BWR owned by Vattenfall AB in Sweden. The paper will describe the working model for upgrading the control room and important issues to take care of with respect to refuelling outages. The identified issues will be used as the input for improving control room philosophy and the individual technical systems. (authors)

  19. Outage probability analysis of wireless sensor networks in the presence of channel fading and spatial correlation

    KAUST Repository

    Al-Murad, Tamim M.

    2011-07-01

    Evaluating the reliability of wireless sensor networks is becoming more important as theses networks are being used in crucial applications. The outage probability defined as the probability that the error in the system exceeds a maximum acceptable threshold has recently been used as a measure of the reliability of such systems. In this work we find the outage probability of wireless sensor network in different scenarios of distributed sensing where sensors\\' readings are affected by spatial correlation and in the presence of channel fading. © 2011 IEEE.

  20. Integrated head area design of KNGR to reduce refueling outage duration

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Woo Tae; Park, Chi Yong; Kim, In Hwan; Kim, Dae Woong [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    In the design of KNGR (Korea Next Generation Reactor), we believe that economy is one of the most important factors to be considered. Thus, we reviewed and evaluated the consequences of designing the head area into an integrated package from an economical point of view. The refueling outage durations of the nuclear power plants currently in operation in Korea, some having and others not having integrated head package, are compared. This paper discusses the characteristics of head area design and the critical design issues of KNGR head area to evaluate the effect of the head area characteristics on the outage duration. 8 refs., 4 figs. (Author)

  1. Investigation into outages of electric power supply as the result of ice storms

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-09-01

    The accumulation of large amounts of ice on electric power distribution conductors and on trees surrounding these conductors has resulted in a number of extended customer electric power outages. Commonwealth Associates, Inc. was assigned the task of reviewing six ice-caused electric outages at the following utilities: Long Island Lighting Company; Portland General Electric; Central Illinois Public Service; Central Illinois Light Company; Dallas River Power and Light; and City Water, Light and Power Department of Springfield, Illinois. Weather conditions that result in ice storms are reviewed. Discussions conducted with public officials in the affected communities and states are described and results and recommendations are presented.

  2. NSM FRP STRENGTHENING RC BEAMS USING HIGH TG FRPS & CEMENTITIOUS ADHESIVES – RESPONSE AT AMBIENT AND ELEVATED TEMPERATURE

    OpenAIRE

    Del Prete, Iolanda

    2015-01-01

    The aging of the built heritage and infrastructures throughout the civil and industrialized world, as well as their deterioration due to environmental effects, and/or changing in service demand, lead to increasing interest in novel techniques aimed to design, maintain and rehabilitate concrete structures. Among the available strengthening techniques for improving the performance of concrete structures, the strengthening with Fibre Reinforced Polymers (FRP) gained huge and fast popularity d...

  3. Textile-reinforced mortar (TRM) versus fiber-reinforced polymers (FRP) in shear strengthening of concrete beams

    OpenAIRE

    Tetta, Z.C.; Koutas, L.N.; Bournas, D.A.

    2015-01-01

    This paper presents an experimental study on shear strengthening of rectangular reinforced concrete (RC) beams with advanced composite materials. Key parameters of this study include: (a) the strengthening system, namely textile-reinforced mortar (TRM) jacketing and fiber-reinforced polymer (FRP) jacketing, (b) the strengthening configuration, namely side-bonding, U-wrapping and full-wrapping, and (c) the number of the strengthening layers. In total, 14 RC beams were constructed and tested un...

  4. Binding of sFRP-3 to EGF in the extra-cellular space affects proliferation, differentiation and morphogenetic events regulated by the two molecules.

    Directory of Open Access Journals (Sweden)

    Raffaella Scardigli

    Full Text Available BACKGROUND: sFRP-3 is a soluble antagonist of Wnts, widely expressed in developing embryos. The Wnt gene family comprises cysteine-rich secreted ligands that regulate cell proliferation, differentiation, organogenesis and oncogenesis of different organisms ranging from worms to mammals. In the canonical signal transduction pathway Wnt proteins bind to the extracellular domain of Frizzled receptors and consequently recruit Dishevelled (Dsh to the cell membrane. In addition to Wnt membrane receptors belonging to the Frizzled family, several other molecules have been described which share homology in the CRD domain and lack the putative trans-membrane domain, such as sFRP molecules (soluble Frizzled Related Protein. Among them, sFRP-3 was originally isolated from bovine articular cartilage and also as a component of the Spemann organizer. sFRP-3 blocks Wnt-8 induced axis duplication in Xenopus embryos and binds to the surface of cells expressing a membrane-anchored form of Wnt-1. Injection of sFRP-3 mRNA blocks expression of XMyoD mRNA and leads to embryos with enlarged heads and shortened trunks. METHODOLOGY/PRINCIPAL FINDINGS: Here we report that sFRP-3 specifically blocks EGF-induced fibroblast proliferation and foci formation. Over-expression of sFRP-3 reverts EGF-mediated inhibition of hair follicle development in the mouse ectoderm while its ablation in Xenopus maintains EGF-mediated inhibition of ectoderm differentiation. Conversely, over-expression of EGF reverts the inhibition of somitic myogenesis and axis truncation in Xenopus and mouse embryos caused by sFRP-3. In vitro experiments demonstrated a direct binding of EGF to sFRP-3 both on heparin and on the surface of CHO cells where the molecule had been membrane anchored. CONCLUSIONS/SIGNIFICANCE: sFRP-3 and EGF reciprocally inhibit their effects on cell proliferation, differentiation and morphogenesis and indeed are expressed in contiguous domains of the embryo, suggesting that in

  5. Technique for reduction of mechanical losses in AC superconducting coils due to thermal expansion properties of various FRP bobbins

    Science.gov (United States)

    Sekine, N.; Tada, S.; Higuchi, T.; Furumura, Y.; Takao, T.; Yamanaka, A.

    2005-10-01

    We reported about reduction of mechanical losses in AC superconducting coils. The method is the use of FRP bobbins fabricated with special fibers. Since their FRPs have negative thermal expansion coefficient to the fiber direction, the FRP bobbins expand to the circumferential direction during cooling down. In case of the superconducting coils with such FRP bobbins, the winding tensions do not decrease during cooling down. Therefore, the mechanical losses are reduced by the suppression of wire's vibration. Their special FRPs are a Dyneema® fiber reinforced plastic (DFRP), a Dyneema and glass fiber reinforced plastic (DGFRP), and a Zylon® fiber reinforced plastic (ZFRP). These materials have negative thermal expansion coefficient to the fiber direction, however, the amplitudes of thermal expansion are various by the quantity or quality of the fiber. In this paper, the values of thermal expansion were actually measured, and it was discussed about the influence on the mechanical losses. At the experimental results, the mechanical loss was small, so that the thermal strain to the circumferential direction on the coil was large. Moreover, in case of the coils with sufficiently strong winding tensions at coil-operating temperature, the mechanical losses vanished.

  6. Technique for reduction of mechanical losses in AC superconducting coils due to thermal expansion properties of various FRP bobbins

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, N. [Tsukamoto Laboratory, Faculty of Engineering, Yokohama National University, 79-5, Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)]. E-mail: n-sekine@tsukalab.dnj.ynu.ac.jp; Tada, S. [Sophia University, 7-1, Kioicho, Chiyoda-ku, Tokyo 102-8554 (Japan); Higuchi, T. [Sophia University, 7-1, Kioicho, Chiyoda-ku, Tokyo 102-8554 (Japan); Furumura, Y. [Sophia University, 7-1, Kioicho, Chiyoda-ku, Tokyo 102-8554 (Japan); Takao, T. [Sophia University, 7-1, Kioicho, Chiyoda-ku, Tokyo 102-8554 (Japan); Yamanaka, A. [Research Center, Toyobo, Co., Ltd, 2-1-1, Katata, Otsu, Shiga 520-0292 (Japan)

    2005-10-01

    We reported about reduction of mechanical losses in AC superconducting coils. The method is the use of FRP bobbins fabricated with special fibers. Since their FRPs have negative thermal expansion coefficient to the fiber direction, the FRP bobbins expand to the circumferential direction during cooling down. In case of the superconducting coils with such FRP bobbins, the winding tensions do not decrease during cooling down. Therefore, the mechanical losses are reduced by the suppression of wire's vibration. Their special FRPs are a Dyneema[reg] fiber reinforced plastic (DFRP), a Dyneema and glass fiber reinforced plastic (DGFRP), and a Zylon[reg] fiber reinforced plastic (ZFRP). These materials have negative thermal expansion coefficient to the fiber direction, however, the amplitudes of thermal expansion are various by the quantity or quality of the fiber. In this paper, the values of thermal expansion were actually measured, and it was discussed about the influence on the mechanical losses. At the experimental results, the mechanical loss was small, so that the thermal strain to the circumferential direction on the coil was large. Moreover, in case of the coils with sufficiently strong winding tensions at coil-operating temperature, the mechanical losses vanished.

  7. Effects of Elevated Temperatures on the Compressive Strength Capacity of Concrete Cylinders Confined with FRP Sheets: An Experimental Investigation

    Directory of Open Access Journals (Sweden)

    Sherif El-Gamal

    2015-01-01

    Full Text Available Due to their high strength, corrosion resistance, and durability, fiber reinforced polymers (FRP are very attractive for civil engineering applications. One of these applications is the strengthening of concrete columns with FRP sheets. The performance of this strengthening technique at elevated temperature is still questionable and needs more investigations. This research investigates the effects of exposure to high temperatures on the compressive strength of concrete cylinders wrapped with glass and carbon FRP sheets. Test specimens consisted of 30 unwrapped and 60 wrapped concrete cylinders. All specimens were exposed to temperatures of 100, 200, and 300°C for periods of 1, 2, and 3 hours. The compressive strengths of the unwrapped concrete cylinders were compared with their counterparts of the wrapped cylinders. For the unwrapped cylinders, test results showed that the elevated temperatures considered in this study had almost no effect on their compressive strength; however, the wrapped specimens were significantly affected, especially those wrapped with GFRP sheets. The compressive strength of the wrapped specimens decreased as the exposure period and the temperature level increased. After three hours of exposure to 300°C, a maximum compressive strength loss of about 25.3% and 37.9%, respectively, was recorded in the wrapped CFRP and GFRP specimens.

  8. Rapid Repair of Earthquake Damaged RC Interior Beam-wide Column Joints and Beam-wall Joints Using FRP Composites

    Institute of Scientific and Technical Information of China (English)

    LI Bing; LIM Chee Leong

    2009-01-01

    This paper studies the seismic performance of FRP-strengthened RC interior non-seismically detailed beam-wide columns and beam-wall joints after limited seismic damage. Four eccentric and concentric beam-wide column joints and two beam-wall joints, initially damaged in a previous study, were repaired and tested under constant axial loads (0. \\fc'Ag and 0. 35 fc'Ag ) and lateral cyclic loading. The rapid repair technique developed, aimed to restore the original strength and to provide minimum drift capacity. The repair schemes were characterized by the use of; (a) epoxy injections and polymer modified cementitious mortar to seal the cracks and replace spalled concrete; and (b) glass (GFRP) and carbon (CFRP) sheets to enhance the joint performance. The FRP sheets were effectively prevented against possible debonding through the use of fiber anchors. Comparison between responses of specimens before and after repair clearly indicated reasonable restoration in strength, drift capacity, stiffness and cumulative energy dissipation capacity. All specimens failed with delamination of FRP sheets at beam-column joint interfaces. The rapid repair technique developed in this study is recommended for mass upgrading or repair of earthquake damaged beam-column joints.

  9. Technique for reduction of mechanical losses in AC superconducting coils due to thermal expansion properties of various FRP bobbins

    International Nuclear Information System (INIS)

    We reported about reduction of mechanical losses in AC superconducting coils. The method is the use of FRP bobbins fabricated with special fibers. Since their FRPs have negative thermal expansion coefficient to the fiber direction, the FRP bobbins expand to the circumferential direction during cooling down. In case of the superconducting coils with such FRP bobbins, the winding tensions do not decrease during cooling down. Therefore, the mechanical losses are reduced by the suppression of wire's vibration. Their special FRPs are a Dyneema[reg] fiber reinforced plastic (DFRP), a Dyneema and glass fiber reinforced plastic (DGFRP), and a Zylon[reg] fiber reinforced plastic (ZFRP). These materials have negative thermal expansion coefficient to the fiber direction, however, the amplitudes of thermal expansion are various by the quantity or quality of the fiber. In this paper, the values of thermal expansion were actually measured, and it was discussed about the influence on the mechanical losses. At the experimental results, the mechanical loss was small, so that the thermal strain to the circumferential direction on the coil was large. Moreover, in case of the coils with sufficiently strong winding tensions at coil-operating temperature, the mechanical losses vanished

  10. Estimating Landscape Fire Particulate Matter (PM) Emissions over Southern Africa using MSG-SEVIRI Fire Radiative Power (FRP) and MODIS Aerosol Optical Thickness Observations

    Science.gov (United States)

    Mota, Bernardo; Wooster, Martin J.

    2016-04-01

    The approach to estimating landscape fire fuel consumption based on the remotely sensed fire radiative power (FRP) thermal energy release rate, as opposed to burned area, is now relatively widely used in studies of fire emissions, including operationally within the Copernicus Atmosphere Monitoring Service (CAMS). Nevertheless, there are still limitations to the approach, including uncertainties associated with using only the few daily overpasses typically provided by polar orbiting satellite systems, the conversion between FRP and smoke emissions, and the increased likelihood that the more frequent data from geostationary systems fails to detect the (probably highly numerous) smaller (i.e. low FRP) component of a regions fire regime. In this study, we address these limitations to directly estimate fire emissions of Particular Matter (PM; or smoke aerosols) by presenting an approach combining the "bottom-up" FRP observations available every 15 minutes across Africa from the Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI) Fire Radiative Product (FRP) processed at the EUMETSAT LSA SAF, and the "top-down" aerosol optical thickness (AOT) measures of the fire plumes themselves as measured by the Moderate-resolution Imaging Spectro-radiometer (MODIS) sensors aboard the Terra (MOD04_L2) and Aqua (MYD04_L2) satellites. We determine PM emission coefficients that relate directly to FRP measures by combining these two datasets, and the use of the almost continuous geostationary FRP observations allows us to do this without recourse to (uncertain) data on wind speed at the (unknown) height of the matching plume. We also develop compensation factors to address the detection limitations of small/low intensity (low FRP) fires, and remove the need to estimate fuel consumption by going directly from FRP to PM emissions. We derive the smoke PM emissions coefficients per land cover class by comparing the total fire radiative energy (FRE) released from individual fires

  11. Reverse Link Outage Probabilities of Multicarrier CDMA Systems with Beamforming in the Presence of Carrier Frequency Offset

    Directory of Open Access Journals (Sweden)

    Xiaoyu Hu

    2007-11-01

    Full Text Available The outage probability of reverse link multicarrier (MC code-division multiple access (CDMA systems with beamforming in the presence of carrier frequency offset (CFO is studied. A conventional uniform linear array (ULA beamformer is utilized. An independent Nakagami fading channel is assumed for each subcarrier of all users. The outage probability is first investigated under a scenario where perfect beamforming is assumed. A closed form expression of the outage probability is derived. The impact of different types of beamforming impairments on the outage probability is then evaluated, including direction-of-arrival (DOA estimation errors, angle spreads, and mutual couplings. Numerical results show that the outage probability improves significantly as the number of antenna elements increases. The effect of CFO on the outage probability is reduced significantly when the beamforming technique is employed. Also, it is seen that small beamforming impairments (DOA estimation errors and angle spreads only affect the outage probability very slightly, and the mutual coupling between adjacent antenna elements does not affect the outage probability noticeably.

  12. Mode-Ⅰ fracture and durability of FRP-concrete bonded interfaces

    Institute of Scientific and Technical Information of China (English)

    Qiao Pizhong; Xu Yingwu

    2008-01-01

    In this study, a work-of-fracture method using a three-point bend beam (3PBB) specimen, which is commonly used to determine the fracture energy of concrete, was adapted to evaluate the mode-Ⅰ fracture and durability of fiber-reinforced polymer (FRP) composite-concrete bonded interfaces. Interface fracture properties were evaluated with established data reduction procedures. The proposed test method is primarily for use in evaluating the effects of freeze-thaw (F-T) and wet-dry (W-D) cycles that are the accelerated aging protocols on the mode-Ⅰ fracture of carbon FRP-concrete bonded interfaces. The results of the mode-Ⅰ fracture tests of F-T and W-D cycle-conditioned specimens show that both the critical load and fracture energy decrease as the number of cycles increases, and their degradation pattern has a nearly linear relationship with the number of cycles. However, compared with the effect of the F-T cycles, the critical load and fracture energy degrade at a slower rate with W-D cycles, which suggests that F-T cyclic conditioning causes more deterioration of carbon fiber-reinforced polymer (CFRP)-concrete bonded interface. After 50 and 100 conditioning cycles, scaling of concrete was observed in all the specimens subjected to F-T cycles, but not in those subjected to W-D cycles. The examination of interface fracture surfaces along the bonded interfaces with varying numbers of F-T and W-D conditioning cycles shows that (1) cohesive failure of CFRP composites is not observed in all fractured surfaces; (2) for the control specimens that have not been exposed to any conditioning cycles, the majority of interface failure is a result of cohesive fracture of concrete (peeling of concrete from the concrete substrate), which means that the cracks mostly propagate within the concrete; and (3) as the number of F-T or W-D conditioning cycles increases, adhesive failure along the interface begins to emerge and gradually increases. It is thus concluded that the fracture

  13. Mode-I fracture and durability of FRP-concrete bonded interfaces

    Directory of Open Access Journals (Sweden)

    Qiao Pizhong

    2008-12-01

    Full Text Available In this study, a work-of-fracture method using a three-point bend beam (3PBB specimen, which is commonly used to determine the fracture energy of concrete, was adapted to evaluate the mode-I fracture and durability of fiber-reinforced polymer (FRP composite-concrete bonded interfaces. Interface fracture properties were evaluated with established data reduction procedures. The proposed test method is primarily for use in evaluating the effects of freeze-thaw (F-T and wet-dry (W-D cycles that are the accelerated aging protocols on the mode-I fracture of carbon FRP-concrete bonded interfaces. The results of the mode-I fracture tests of F-T and W-D cycle-conditioned specimens show that both the critical load and fracture energy decrease as the number of cycles increases, and their degradation pattern has a nearly linear relationship with the number of cycles. However, compared with the effect of the F-T cycles, the critical load and fracture energy degrade at a slower rate with W-D cycles, which suggests that F-T cyclic conditioning causes more deterioration of carbon fiber-reinforced polymer (CFRP-concrete bonded interface. After 50 and 100 conditioning cycles, scaling of concrete was observed in all the specimens subjected to F-T cycles, but not in those subjected to W-D cycles. The examination of interface fracture surfaces along the bonded interfaces with varying numbers of F-T and W-D conditioning cycles shows that (1 cohesive failure of CFRP composites is not observed in all fractured surfaces; (2 for the control specimens that have not been exposed to any conditioning cycles, the majority of interface failure is a result of cohesive fracture of concrete (peeling of concrete from the concrete substrate, which means that the cracks mostly propagate within the concrete; and (3 as the number of F-T or W-D conditioning cycles increases, adhesive failure along the interface begins to emerge and gradually increases. It is thus concluded that the

  14. Study on compression performance of FRP rubber bearing%FRP橡胶支座压缩性能分析

    Institute of Scientific and Technical Information of China (English)

    张华; 彭天波; 李建中; 李文晓

    2011-01-01

    将纤维复合材料板(FRP)代替传统板式橡胶支座中的加劲钢板,可以得到一种新型的橡胶支座隔振器,即FRP橡胶支座.文中首先对FRP橡胶支座的概念及特点作了基本介绍,之后,为了了解其在竖向加载情况下的力学性能,为FRP橡胶支座竖向承载力及压缩刚度的设计提供了参考,利用通用有限元程序对FRP橡胶支座进行了有限元数值模拟,对支座在竖向加载作用下的力学性能进行了研究,讨论了支座的变形情况以及FRP加劲板应力的大小及分布情况,对比研究了由数值模拟、理论分析以及试验研究得到的FRP橡胶支座的压缩刚度.从对支座中FRP加劲板的应力情况以及支座的刚度性能可以看出,使用FRP加劲板替代板式橡胶支座中的加劲钢板来制作新型FRP橡胶支座是可行的.%FRP rubber bearing, made by replacing the steel reinforcement in traditional laminated rubber bearing with fiber reinforcement, is a novel rubber isolator. The concept and the characteristics of FRP rubber bearing are introduced in this paper. To provide some references to the designing of the vertical bearing capacity and compression stiffness of FRP rubber bearing, the compression performance of the bearing is studied. The finite element model is set up. The deformation of the bearing and the stress distribution of the fiber reinforcement under a given pressure are discussed. Comparison of the compression stiffness values from different methods, including numerical method, analytical method and experimental method, is made to validate the modeling method used and the results shows that it is effective. The results of the stress in the fiber reinforcement and the compression stiffness of the bearing show that it is feasible to replace the steel reinforcement with fiber reinforcement to manufacture FRP rubber bearing with well compression performance.

  15. Planning maintenance during the first outage and refuelling of Qinshan 300 MW Nuclear Power Unit

    International Nuclear Information System (INIS)

    To take an example in the equipment maintenance of the primary circuit and auxiliary systems, this paper sums up the first outage and refuelling planning maintenance of Qinshan 300 MW Nuclear Power Unit. It concludes the guiding principle and preparatory treatment. Some suggestions are put forward. These suggestions provide active function for improving planning maintenance and management of Qinshan Nuclear Power Plant

  16. Health and maintenance outages in nuclear power plants: an epidemiological survey

    International Nuclear Information System (INIS)

    An epidemiological survey, started in 1989, was carried out at the nuclear power plants in the Loire river valley and at Le Blayais (France). Working conditions, work organisation and their impact on health during annual maintenance outages were studied. The main areas covered in this cross-sectional study were: anxiety and symptoms of depression using the Spielberger and CES-D scales. Comparisons were made during both a scheduled outage and in normal operation on four distinct groups of workers, each individual being his own control. A chi-square test was used for the quantitative variables and a test on differences for the quantitative variables. During a unit outage, more frequent overtime and atypical working hours were reported (p<0.01); working rhythms and safety rules were felt as more restrictive and exposure to radiation higher (p<0.01). Detrimental modifications of anxiety and symptoms of depression were observed on controllers whereas expected on maintenance agents. Similar results were observed when considering the rates of outages. Possible readings are given with reference to qualitative studies carried out on this topic, which implies extending our research with both the quantitative and qualitative approaches. (authors). 10 refs., 6 tabs

  17. Competitive outage lengths when servicing the liquid relief valves of the heat transport system

    International Nuclear Information System (INIS)

    Conservative engineering judgement has been frequently used to decide how early into an outage certain type of maintenance work for key elements of the Heat Transport System (HTS) can be conducted. The immediate consequence of this approach is that the length of the outages is increased unnecessarily because this maintenance work often becomes the critical path and, in an environment of competition such as the up coming open market for electricity in Ontario, short duration outages provide great strategic advantages. This paper presents the work done to relax the 30-day waiting period to block closed the LRVs. A detailed model of the HTS which includes the SDCS and the LCH piping connection to the D2O Storage Tank was developed for the state-of-the-art Two Unequal Fluids (TUF) computer code. The results of the simulations with the TUF code have shown that the LCH can be credited as the overpressure relief path as early as two days after unit shutdown in case of loss of forced circulation (e.g., loss of Class III Power to the SDCS pumps). The financial savings and the additional flexibility in planning outage work due to the reduction of the waiting period by a factor of 15 are apparent. (author)

  18. COG CANDU outage optimization project at Wolsong, Qinshan, Cernavoda, Point Lepreau, Darlington and Pickering

    Energy Technology Data Exchange (ETDEWEB)

    McWilliams, L. [CANDU Owners Group, Toronto, Ontario (Canada)

    2011-07-01

    This COG initiated project objective is to reduce the timeline CANDU power plants are shutdown for planned maintenance outages through knowledge sharing, benchmarking and completion of a Gap Analysis. The following CANDU Nuclear Power Stations/Facilities formed a partnership to achieve the objective: Korean Hydro and Nuclear Power Company (Wolsong), Qinshan, Societatea Nationala 'Nuclearelectrica' (Cernavoda), New Brunswick Power Nuclear (Point Lepreau), Candu Energy Inc. (formerly AECL) and Ontario Power Generation Inc. (Darlington and Pickering). Project participants selected ten focus areas to evaluate and optimize. Benchmarking studies were conducted at each utility. A Gap Analysis was performed between the stations and site specific recommendations have been made considering: Critical path improvement opportunities (Unit Shutdown, RBLRT and Unit Start up); Major work program improvement opportunities (Turbine/Generator, Electrical Maintenance, MOT, SST and the Valve Program); Recommended modifications to reduce outage durations; and, Process Improvements (standardized clearance process). A final report has been issued to each station identifying: Gap Analysis Comparison results; Best Practices for each area studied; Site specific improvement opportunities; Most Effective Process for Outage Preparation; Most Effective Outage Execution Practices; and, Contingency Plan Preparation. Results were discussed during the presentation.

  19. Application of Hybrid Geo-Spatially Granular Fragility Curves to Improve Power Outage Predictions

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Steven J [ORNL; Allen, Melissa R [ORNL; Omitaomu, Olufemi A [ORNL; Walker, Kimberly A [ORNL

    2014-01-01

    Fragility curves depict the relationship between a weather variable (wind speed, gust speed, ice accumulation, precipitation rate) and the observed outages for a targeted infrastructure network. This paper describes an empirical study of the county by county distribution of power outages and one minute weather variables during Hurricane Irene with the objective of comparing 1) as built fragility curves (statistical approach) to engineering as designed (bottom up) fragility curves for skill in forecasting outages during future hurricanes; 2) county specific fragility curves to find examples of significant deviation from average behavior; and 3) the engineering practices of outlier counties to suggest future engineering studies of robustness. Outages in more than 90% of the impacted counties could be anticipated through an average or generic fragility curve. The remaining counties could be identified and handled as exceptions through geographic data sets. The counties with increased or decreased robustness were characterized by terrain more or less susceptible to persistent flooding in areas where above ground poles located their foundations. Land use characteristics of the area served by the power distribution system can suggest trends in the as built power grid vulnerabilities to extreme weather events that would be subjects for site specific studies.

  20. Consequences of long-term power outages and high electricity prices lasting for months

    International Nuclear Information System (INIS)

    Several areas in the world have experienced electricity outages for longer periods of time, but the consequences of these are sparsely documented. There is a need for further analysis of the socioeconomic consequences of the outages. In addition to KILE (Quality adjusted revenue framework for un supplied energy) costs one has to take into account that the costs often increase proportionally with the durance of the outage, and that KILE tariffs do not reflect lost consumer's surplus for products that are not produced during an outage. A good example is the public underground transport, where the company's economical loss can be significantly smaller than the loss of utility value for the travellers. If the authorities act with reasonability it is difficult to see that periods with very high prices represent a big problem. The most important problems are related to diffused effects, especially for households with a weak economy. These problems can be solved with improved contractual forms (price guarantees) or by transfers to the households, without weakening the incentives for electricity economising (ml)

  1. World-class outage performance of the Olkiluoto nuclear power plant

    International Nuclear Information System (INIS)

    The production of the Olkiluoto power plant units covered 17% of the electricity consumption in Finland in 1997; the total share of nuclear energy was 27% of the electricity consumed in the country. Based on Finnish experience, nuclear energy is a safe, environmentally friendly and economic way to produce electricity provided that the plants and their personnel are well taken care of. TVO's policy is to keep the plant units in good condition and technically modern. This requires continuous investments in the plant. In maintenance, attention is paid to monitoring the condition of the plant and to preventive maintenance aiming at avoiding disturbances in production. TVO has chosen continuous development as the operational line develops the plant by annual investments and performs the necessary modifications during planned annual outages trying to avoid long production interruptions. The load factors of the Olkiluoto nuclear power plant have been high. The average load factor during the last decade was over 93%. The most significant single factor in the production deficits is the amount or electricity, which has not been produced because of the annual outages. Due to this, special attention has been paid to the performance of the annual outages. TVO aims at continuous development of the annual outage procedure. A centralized task management system makes it possible to perform simultaneously more tasks than before. The company has also invested in equipment and systems, which ease and speed up servicing. Normal outage length varies between 10 and 16 days. By keeping the plant units as modern as possible and in good condition we facilitate reaching TVO's target, which is also stated in TVO's slogan 'always 40 years lifetime'. (author)

  2. Characterization of Ti6Al4V for integral transition structures in FRP-aluminum compounds

    Energy Technology Data Exchange (ETDEWEB)

    Schimanski, Kai; Schumacher, Jens; Von Hehl, Axel; Zoch, Hans-Werner [Stiftung Institut fuer Werkstofftechnik, Bremen (Germany); Wottschel, Vitalij; Vollertsen, Frank [Bremer Institut fuer Angewandte Strahltechnik, Bremen (Germany)

    2012-08-15

    Components in hybrid design become more and more important in terms of their lightweight potential. In this context, the demand for weight saving in aerospace industry leads to increase numbers of applications of fiber reinforced composites for primary structural components. In consequence, the use of FRP-metal compounds is necessary. In the context of the investigations of the researcher group named ''Black-Silver'' (''Schwarz Silber'', FOR 1224) founded by the DFG (German Research Foundation) material optimized interface structures for advanced carbon fiber reinforced plastic (CFRP)-aluminum compounds are currently being studied. Within their work the researcher group focussed on three concepts realizing the transition structures: the usage of wires (titanium), foils (titanium), and fibers (glass fiber) as transition elements between CFRP and aluminum. For the connection of the aluminum sheet and the transition element die-casting and laser beam welding are basically used. The paper concentrates on the characterization of suitable materials for transition structures. Due to their high strength and low density (in comparison to steel) and the resulting potential in view on light-weight design Ti-alloys were investigated. Because of the increased availability of Ti-wires compared to Ti-foils in suitable thickness the former were used for the basic investigations on Ti-alloys which are suitable for integral transition structures. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Diffusion bonding of transition structures for integral aluminium-fibre reinforced polymer (FRP) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hehl, A. von [IWT - Stiftung Institut fuer Werkstofftechnik, Hauptabteilung Werkstofftechnik, Bremen (Germany); Syassen, F. [Airbus Operations GmbH, Metal Technology, Bremen (Germany); Schimanski, K.

    2012-04-15

    Components in hybrid design become more and more important in terms of their lightweight potential. In this context the demand for weight saving in aerospace leads to increasing numbers of applications of fibre composites for primary structural components. In consequence the use of FRP-metal compounds is necessary. Within the investigations of the researcher group ''Schwarz Silber'' (FOR 1224) founded by the DFG (German Research Foundation) material optimised interface structures for advanced CFRP-aluminium compounds are currently being studied. Within their work the researcher group focussed on three concepts realizing the transition structures: the usage of wires (titanium), foils (titanium) and fibres (glass fibre) as transition elements between CFRP and aluminium. For the connection of the aluminium sheet and the transition element die-casting and laser beam welding are basically used. As a possible alternative to the both liquid phase processes a feasibility study haven been done focussing the solid state processes diffusion bonding. The experimental results show the high potential of this process in view of the transferable loads for integral transition structures. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Research and Development on Control System of Novel Winding Machine for High-pressure FRP Pipeline

    Institute of Scientific and Technical Information of China (English)

    YOU Bo; XU Jiazhong; HU Haiyan; CHENG Ningbo; ZHANG Qingli

    2006-01-01

    The novel winding machine adopted steam inside solidification technics, can wind, solidify and extract high-pressure fiber reinforced plastic (FRP) pipelines in one single machine. Its control system consisted of the winding and extraction subsystem and the steam inside solidification subsystem. In order to improve the control precision and stability, a real-time control method was adopted in the winding and extraction subsystem. In this method, high-precision TRIO motion controller combined with industrial personal computer (IPC) forms an open-type CNC system which supports multitask. The Modbus protocol was adopted for the communication between the IPC and TRIO motion controller. The human-machine interface (HMI) was developed with VC++ 6.0 and the control software of the motion controller was developed with TRIO BASIC language. In the steam inside solidification subsystem, embedded IPC and PLC were used to realize the closed-loop control of the steam temperature and the HMI was developed with MCGS 5.1 under WinCE. Practices show that this system has the good performances of high precision, good stability and high efficiency.

  5. Microtomographic Analysis of Impact Damage in FRP Composite Laminates: A Comparative Study

    Directory of Open Access Journals (Sweden)

    M. Alemi-Ardakani

    2013-01-01

    Full Text Available With the advancement of testing tools, the ability to characterize mechanical properties of fiber reinforced polymer (FRP composites under extreme loading scenarios has allowed designers to use these materials in high-level applications more confidently. Conventionally, impact characterization of composite materials is studied via nondestructive techniques such as ultrasonic C-scanning, infrared thermography, X-ray, and acoustography. None of these techniques, however, enable 3D microscale visualization of the damage at different layers of composite laminates. In this paper, a 3D microtomographic technique has been employed to visualize and compare impact damage modes in a set of thermoplastic laminates. The test samples were made of commingled polypropylene (PP and glass fibers with two different architectures, including the plain woven and unidirectional. Impact testing using a drop-weight tower, followed by postimpact four-point flexural testing and nondestructive tomographic analysis demonstrated a close relationship between the type of fibre architecture and the induced impact damage mechanisms and their extensions.

  6. sFRP-mediated Wnt sequestration as a potential therapeutic target for Alzheimer's disease.

    Science.gov (United States)

    Warrier, Sudha; Marimuthu, Raja; Sekhar, Sreeja; Bhuvanalakshmi, G; Arfuso, Frank; Das, Anjan Kumar; Bhonde, Ramesh; Martins, Ralph; Dharmarajan, Arun

    2016-06-01

    The extracellular ligand, Wnt, and its receptors are involved in sign al transduction and play an important role in axis formation and neural development. In neurodegenerative disorders such as Alzheimer's disease (AD), a decrease of the intracellular Wnt effector, β-catenin, has been linked to amyloid-β-peptide-induced neurotoxicity. Despite this knowledge, targeting Wnt inhibitors as potential biomarkers has not been explored, and harnessing Wnt activators as therapeutic candidates remains largely not investigated. A wide acting family of Wnt mediators, secreted frizzled-related proteins (sFRPs), has not been probed so far as molecular indicators of disease occurrence and progression of Alzheimer's. Unlike the effect of the Dickkopf (DKK) family of Wnt antagonists on AD, the sFRP molecules have a more pleiotropic impact on the Wnt signaling cascade and probably have a far-reaching involvement in neurodegeneration. The role of sFRPs has been poorly described in AD, and in this review, we analyze the present status of the role of sFRPs on neurodegeneration, their likely involvement, and potential implications in treatment modalities of AD. This information would provide valuable clues for the development of potential therapeutic targets for aberrant neurodegenerative disorders. PMID:27063405

  7. Behavior of concrete filled FRP tubes under fully reversed cyclic bending

    International Nuclear Information System (INIS)

    Concrete filled Fiber Reinforced Polymer (FRP) tubes (CFFT) are currently being used as piles in corrosive marine applications and as columns in bridge piers, and could be used in overhead sign structures. CFFTs provide a non-corrosive alternative to conventional materials. Studies conducted on CFFTs in the past decade have been mostly focused on the short-term monotonic behavior of this system in bending and under axial loads, with hardly any information available on their fatigue behavior. In this paper the details of a research program that was conducted to address this issue and its results are presented. The program included the testing of two full-scale specimens under reversed cyclic bending. The program also included the testing of several coupons, cut from the tubes in tension-tension fatigue. The full scale tests showed that CFFTs seem to have a relatively short fatigue life under bending moments of 40% and higher of their ultimate static bending moment capacities and that strains and deflections tend to increase gradually during cyclic bending indicating a stiffness degradation behavior. The coupon test showed that rapid stiffness degradation occurs initially then reduces due to the cracking of matrix in the hoop layers and that a fatigue life of millions of cycles could be reached for stresses less than 30% of the ultimate tensile stress. (author)

  8. Meteosat SEVIRI Fire Radiative Power (FRP products from the Land Surface Analysis Satellite Applications Facility (LSA SAF – Part 1: Algorithms, product contents and analysis

    Directory of Open Access Journals (Sweden)

    M. J. Wooster

    2015-06-01

    Full Text Available Characterising changes in landscape scale fire activity at very high temporal resolution is best achieved using thermal observations of actively burning fires made from geostationary Earth observation (EO satellites. Over the last decade or more, a series of research and/or operational "active fire" products have been developed from these types of geostationary observations, often with the aim of supporting the generation of data related to biomass burning fuel consumption and trace gas and aerosol emission fields. The Fire Radiative Power (FRP products generated by the Land Surface Analysis Satellite Applications Facility (LSA SAF from data collected by the Meteosat Second Generation (MSG Spinning Enhanced Visible and Infrared Imager (SEVIRI are one such set of products, and are freely available in both near real-time and archived form. Every 15 min, the algorithms used to generate these products identify and map the location of new SEVIRI observations containing actively burning fires, and characterise their individual rates of radiative energy release (fire radiative power; FRP that is believed proportional to rates of biomass consumption and smoke emission. The FRP-PIXEL product contains the highest spatial resolution FRP dataset, delivered for all of Europe, northern and southern Africa, and part of South America at a spatial resolution of 3 km (decreasing away from the west African sub-satellite point at the full 15 min temporal resolution. The FRP-GRID product is an hourly summary of the FRP-PIXEL data, produced at a 5° grid cell size and including simple bias adjustments for meteorological cloud cover and for the regional underestimation of FRP caused, primarily, by the non-detection of low FRP fire pixels at SEVIRI's relatively coarse pixel size. Here we describe the enhanced geostationary Fire Thermal Anomaly (FTA algorithm used to detect the SEVIRI active fire pixels, and detail methods used to deliver atmospherically corrected FRP

  9. Analysis of Chain of Events in Major Historic Power Outages

    Directory of Open Access Journals (Sweden)

    HUANG, T.

    2014-08-01

    Full Text Available Contemporary power systems are facing increasing intricate conditions that have never been considered when initially designing the infrastructure, such as malicious threats, accommodating smart grids, etc. As a consequence, blackouts albeit seldom but stubbornly keep appearing from time to time the world around, and demonstrate their devastating capability to create vast damage on both power systems and the society at large. Patterns of the blackout starting from the first triggering events to the system final status have emerged. A framework of a coding system was proposed in this paper in order to capture the common feature in the system evolution during the development of cascades. Cascades in a blackout can be tracked by a chain of events with the help of the codes. It is facile to adopt the framework to build up a knowledge base of blackouts. By applying the proposed framework to 31 selected historic blackouts, most frequent events, effects and origins are identified; the findings can provide useful information for grid designers and security experts for ranking the most imminent issues in their study.

  10. Proceedings of a joint OECD/NEA-IAEA symposium on human factors and organisation in NPP maintenance outages: impact on safety

    International Nuclear Information System (INIS)

    The sessions of this conference dealt with outage strategy and methods (in Sweden, France and United States), the organisation and management of outages (organisation during refuelling shutdowns in France, safety approaches in France, in the USA, in Canada, in the United Kingdom and in Sweden), case studies and lessons learned (in France, Korea, Sweden, UK, USA), regulatory aspects of outages (UK, Germany, Mexico, France), the development of outage techniques

  11. Effects of the April 1st, 2014 GLONASS Outage on GNSS Receivers

    Science.gov (United States)

    Blume, F.; Berglund, H. T.; Romero, I.; D'Anastasio, E.

    2014-12-01

    The use of multi-constellation GNSS receivers has been assumed as a way to increase system integrity both by increased coverage during normal operations and failover redundancy in the event of a constellation failure. At approximately 21:00 UTC on April 1st the entire GLONASS constellation was disrupted as illegal ephemeris uploaded to each satellite took effect simultaneously. The outage continued for more than 10 hours. While ephemeris were incorrect, pseudoranges were correctly broadcast on both L1 and L2 and carrier phases were not affected; in the best case, GNSS receivers could be expected to continue to track all signals including GLONASS and at the worst to continue to track GPS and other constellations. It became clear to operators of the GeoNet network in New Zealand that the majority of their 79 GLONASS-enabled receivers experienced total tracking failures. Further detailed analysis of data from these and 315 additional GLONASS-enabled stations worldwide showed that receiver tracking behavior was affected for most receiver brands and models, both for GLONASS and GPS. Findings regarding the impacts of the GLONASS outage on receiver behavior will be highlighted. We use data recorded by GLONASS enabled global sites for the days during, preceding and following the outage to evaluate the impact of the outage on tracking and positioning performance. We observe that for some receiver types the onboard receiver autonomous integrity monitoring (RAIM) failed to ignore the incorrect messages, resulting in degraded GLONASS and GPS tracking and in some cases complete tracking failures and significant data loss. In addition, many of the receivers with clock steering enabled showed outliers in their receiver clock bias estimates that also coincided with the outage. Our results show in detail how different brands, configurations, and distributions of receivers were affected to varying extents, but no common factors are apparent. This event shows that many manufacturers

  12. Outage planning in nuclear power plants. A paradigm shift from an external towards an integrated project planning tool

    International Nuclear Information System (INIS)

    Latest demands on nuclear plant inspections are the ongoing actualisation of the outage plan on the basis of the current work progress and current events as well as the permanent access to the current planning status and work process of all people involved in the outage. Modern EAM systems (EAM: Enterprise Application Management) made up ground on established project planning tools with regard to functionalities for scheduling work orders. A shift towards an integrated planning in the EAM system increases the efficiency in the outage planning and improves the communication of current states of planning. (orig.)

  13. Analysis of 58Co activity concentration in the primary coolant during CPR1000 NPP shut down for outage

    International Nuclear Information System (INIS)

    Activated corrosion products which deposit on inner walls of primary coolant are the main radioactive sources in PWR NPPs during outage. A method for estimating the 58Co activity concentration during outage was proposed in this paper. By analysis, we can get that the purification rate and the release rate in the primary coolant are the main factors changes of the 58co activity concentration, and the 58Co activity concentration meet the related requirement of Outage limits in CPR1000 nuclear power plant. (authors)

  14. MiR-27a targets sFRP1 in hFOB cells to regulate proliferation, apoptosis and differentiation.

    Directory of Open Access Journals (Sweden)

    Donggeng Guo

    Full Text Available MicroRNAs (miRNAs play a key role in the regulation of almost all the physiological and pathological processes, including bone metabolism. Recent studies have suggested that miR-27 might play a key role in osteoblast differentiation and bone formation. Increasing evidence indicates that the canonical Wnt signaling pathway contributes to different stages of bone formation. In this study, we identify miR-27a can promote osteoblast differentiation by repressing a new target, secreted frizzled-related proteins 1 (sFRP1 expression at the transcriptional level. Here, 21 candidate targets of miR-27a involved in canonical Wnt/β-catenin signaling were predicted, and a significant decrease in sFRP1 luciferase activity was observed both in 293T and MG63 cells co-transfected with the matched luciferase reporter constructs and miR-27a mimic. Furthermore, the presence of exogenous miR-27a significantly decreased sFRP1 mRNA and protein expression in hFOB1.19 cells during both proliferation and osteogenic differentiation. The over-expression of miR-27a or knockdown sFRP1 significantly increased the percentage of apoptotic hFOBs, the percentage of cells in the G2-M phase of the cell cycle and the expression of key osteoblastic markers, including ALP, SPP1, RUNX2 and ALP activity. Over-expression of miR-27a or knockdown of endogenous sFRP1 led to an accumulation of β-catenin in hFOBs. In the present study, we demonstrate that miR-27a induced gene silencing effect is a vital mechanism contributing to bone metabolism in hFOB cells in vitro, which is partly affected by the post-transcriptional regulation of sFRP1, during osteoblast proliferation, apoptosis and differentiation.

  15. Prediction of power system frequency response after generator outages using neural nets

    Energy Technology Data Exchange (ETDEWEB)

    Djukanovic, M.B.; Popovic, D.P. (Electrotechnicki Inst. ' Nikola Tesla' , Belgrade (Yugoslavia)); Sobajic, D.J.; Pao, Y.-H. (Case Western Reserve Univ., Cleveland, OH (United States))

    1993-09-01

    A new methodology is presented for estimating the frequency behaviour of power systems necessary for an indication of under-frequency load shedding in steady-state security assessment. It is well known that large structural disturbances such as generator tripping or load outages can initiate cascading outages, system separation into islands, and even the complete breakup. The approach provides a fairly accurate method of estimating the system average frequency response without making simplifications or neglecting non-linearities and small time constants in the equations of generating units, voltage regulators and turbines. The efficiency of the new procedure is demonstrated using the New England power system model for a series of characteristic perturbations. The validity of the proposed approach is verified by comparison with the simulation of short-term dynamics including effects of control and automatic devices. (author)

  16. Recent performance of and plasma outage studies with the SNS H- source

    Science.gov (United States)

    Stockli, M. P.; Han, B.; Murray, S. N.; Pennisi, T. R.; Piller, C.; Santana, M.; Welton, R.

    2016-02-01

    Spallation Neutron Source ramps to higher power levels that can be sustained with high availability. The goal is 1.4 MW despite a compromised radio frequency quadrupole (RFQ), which requires higher radio frequency power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H- beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ˜55-kW 2-MHz plasma pulses reflecting ˜90% of the continuous ˜300 W, 13-MHz power, which was mitigated with a 4-ms filter for the reflected power signal and an outage resistant, slightly detuned 13-MHz match. Lowering the H2 gas also increased the H- beam current to ˜55 mA and increased the RFQ transmission by ˜7% (relative).

  17. On the outage capacity of the block fading channel at low-power regime

    KAUST Repository

    Rezki, Zouheir

    2014-06-01

    Outage performance of the M-block fading with additive white Gaussian noise (BF-AWGN) is investigated at low-power regime. We consider delay-constrained constant-rate communications with perfect channel state information (CSI) at both the transmitter and the receiver (CSI-TR), under a short-term power constraint. We show that selection diversity that allocates all the power to the strongest block is asymptotically optimal. Then, we provide a simple characterization of the outage probability in the regime of interest. We quantify the reward due to CSI-TR over the constant-rate constant-power scheme and show that this reward increases with the delay constraint. For instance, for Rayleigh fading, we find that a power gain up to 4.3 dB is achievable. © 2014 IEEE.

  18. Outage and Capacity Performance Evaluation of Distributed MIMO Systems over a Composite Fading Channel

    Directory of Open Access Journals (Sweden)

    Wenjie Peng

    2014-01-01

    Full Text Available The exact closed-form expressions regarding the outage probability and capacity of distributed MIMO (DMIMO systems over a composite fading channel are derived. This is achieved firstly by using a lognormal approximation to a gamma-lognormal distribution when a mobile station (MS in the cell is in a fixed position, and the so-called maximum ratio transmission/selected combining (MRT-SC and selected transmission/maximum ratio combining (ST-MRC schemes are adopted in uplink and downlink, respectively. Then, based on a newly proposed nonuniform MS cell distribution model, which is more consistent with the MS cell hotspot distribution in an actual communication environment, the average outage probability and capacity formulas are further derived. Finally, the accuracy of the approximation method and the rationality of the corresponding theoretical analysis regarding the system performance are proven and illustrated by computer simulations.

  19. Recent Performance of and Plasma Outage Studies with the SNS H- Source

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, Martin P [ORNL; Han, Baoxi [ORNL; Murray Jr, S N [ORNL; Pennisi, Terry R [ORNL; Piller, Chip [ORNL; Santana, Manuel [ORNL; Welton, Robert F [ORNL

    2016-01-01

    SNS ramps to higher power levels that can be sustained with high availability. The goal is 1.4 MW despite a compromised RFQ, which requires higher RF power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H- beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ~55-kW 2-MHz plasma pulses reflecting ~90% of the continuous ~300W, 13-MHz power, which was mitigated with a 4-ms filter for the reflected power signal and an outage resistant, slightly-detuned 13-MHz match. Lowering the H2 also increased the H- beam current to ~55 mA, and increased the transmission by ~7%.

  20. Method for estimating power outages and restoration during natural and man-made events

    Energy Technology Data Exchange (ETDEWEB)

    Omitaomu, Olufemi A.; Fernandez, Steven J.

    2016-01-05

    A method of modeling electric supply and demand with a data processor in combination with a recordable medium, and for estimating spatial distribution of electric power outages and affected populations. A geographic area is divided into cells to form a matrix. Within the matrix, supply cells are identified as containing electric substations and demand cells are identified as including electricity customers. Demand cells of the matrix are associated with the supply cells as a function of the capacity of each of the supply cells and the proximity and/or electricity demand of each of the demand cells. The method includes estimating a power outage by applying disaster event prediction information to the matrix, and estimating power restoration using the supply and demand cell information of the matrix and standardized and historical restoration information.

  1. On the Outage Performance of Full-Duplex Selective Decode-and-Forward Relaying

    KAUST Repository

    Khafagy, Mohammad Galal

    2013-02-25

    We evaluate the outage performance in a three-terminal full-duplex relay channel that adopts a selective decode-and-forward protocol, taking relay self-interference into account. Previous work focused on coverage extension scenarios where direct source-destination transmissions are neglected or considered as interference. In this work, we account for the relay self-interference, and exploit the cooperative diversity offered by the independently fading source/relay message replicas that arrive at the destination. We present an approximate, yet accurate, closed-form expression for the end-to-end outage probability that captures their joint effect. With the derived expression in hand, we propose a relay transmit power optimization scheme that only requires the relay knowledge of channel statistics. Finally, we corroborate our analysis with simulations.

  2. DURABILITY OF CONCRETE STRUCTURES STRENGTHENED EXTERNALLY USING FIBER REINFORCED POLYMER (FRP) AND IT???S PERFORMANCE DUE TO SEA ENVIRONTMENT

    OpenAIRE

    RUDY DJAMALUDDIN; . IRMAWATI; . SHINICHI HINO

    2014-01-01

    Overall objective of the research is to establish a strengthening method for damaged concrete structures using Fiber Reinforced Plastics (FRP) as well as to have an understanding of the effect of the tropic and sub-tropic sea environment to its durability and performance. Due to the change of the life demands, the structures may be experiencing changes in the function and an increase in service load so that the structures is no longer safe for use and it may cause a damage on th...

  3. Efficient Cooperative Protocols for General Outage-Limited Multihop Wireless Networks

    OpenAIRE

    Maham, Behrouz; Saad, Walid; Debbah, Merouane; Han, Zhu; Hjorungnes, Are

    2010-01-01

    Due to the limited energy supplies of nodes in wire- less networks, achieving energy efficiency is crucial for extending the lifetime of these networks. Thus, we study efficient power allocations and transmission protocols for outage-restricted mul- tihop wireless networks based on cooperative transmission. In such multihop networks, a number of nodes, acting as relays, can assist a source node in the transmission of its messages to a single destination. In this paper, several multihop transm...

  4. Risk-Based Allowed Outage Time and Surveillance Test Interval Extensions for Angra 1

    OpenAIRE

    Orlando Gibelli, Sonia M.; e Melo, P. F. Frutuoso; Bogado Leite, Sérgio Q.

    2012-01-01

    In this work, Probabilistic Safety Assessment (PSA) is used to evaluate Allowed Outage Times (AOT) and Surveillance Test Intervals (STI) extensions for three Angra 1 nuclear power plant safety systems. The interest in such an analysis lies on the fact that PSA comprises a risk-based tool for safety evaluation and has been increasingly applied to support both the regulatory and the operational decision-making processes. Regarding Angra 1, among other applications, PSA is meant to be an additio...

  5. Use of VIIRS DNB Data to Monitor Power Outages and Restoration for Significant Weather Events

    Science.gov (United States)

    Jedlovec, Gary; Molthan, Andrew

    2008-01-01

    NASA fs Short-term Prediction Research and Transition (SPoRT) project operates from NASA's Marshall Space Flight Center in Huntsville, Alabama. The team provides unique satellite data to the National Weather Service (NWS) and other agencies and organizations for weather analysis. While much of its work is focused on improving short-term weather forecasting, the SPoRT team supported damage assessment and response to Hurricane Superstorm Sandy by providing imagery that highlighted regions without power. The team used data from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. The VIIRS low-light sensor, known as the day-night-band (DNB), can detect nighttime light from wildfires, urban and rural communities, and other human activity which emits light. It can also detect moonlight reflected from clouds and surface features. Using real time VIIRS data collected by our collaborative partner at the Space Science and Engineering Center of the University of Wisconsin, the SPoRT team created composite imagery to help detect power outages and restoration. This blackout imagery allowed emergency response teams from a variety of agencies to better plan and marshal resources for recovery efforts. The blackout product identified large-scale outages, offering a comprehensive perspective beyond a patchwork GIS mapping of outages that utility companies provide based on customer complaints. To support the relief efforts, the team provided its imagery to the USGS data portal, which the Federal Emergency Management Agency (FEMA) and other agencies used in their relief efforts. The team fs product helped FEMA, the U.S. Army Corps of Engineers, and U.S. Army monitor regions without power as part of their disaster response activities. Disaster responders used the images to identify possible outages and effectively distribute relief resources. An enhanced product is being developed and integrated into a web

  6. Extreme Outages due to Polarization Mode Dispersion First- and Higher- Order Compensations

    CERN Document Server

    Chernyak, V; Kolokolov, I V; Lebedev, V; Chernyak, Vladimir; Chertkov, Michael; Kolokolov, Igor; Lebedev, Vladimir

    2003-01-01

    Joint effect of weak birefringent disorder and amplifier noise on transmission in optical fiber communication systems is properly described in terms of the Probability Distribution Function (PDF) of Bit Error Rate (BER). The PDF tail, correspondent to extreme outages and thus anomalously large values of Bit Error Rate (BER), was analyzed in [1]. In the letter we extend this analysis for the case of the first- and higher-order PMD compensation schemes.

  7. Study on European Nuclear Safety Practices during Planned Outages at Nuclear Power Plants

    International Nuclear Information System (INIS)

    The present project was aimed at providing: a description of the current status of nuclear safety practices during planned outages at nuclear power plants followed in Europe; the criteria for the safety analysis of future reactors at the design stage; proposing a set of recommendations on good practices and criteria leading to the improvement of nuclear safety during those conditions. The work was organised in 3 phases: Collecting data on current practices; Analysis of questionnaire answers and drawing up of safety good practices references and recommendations; Collecting relevant ideas related to the future reactors at design stage (European Pressurised Water Reactor, European Passive Plant project, European Utilities Requirements and Utilities Requirement Document project). The key element of the performed work was the detailed questionnaire, based on bibliographical review, expert experience and outage practices available in the working team. Different safety areas and activities were covered: outage context; nuclear safety; outage strategy, organisation and control; operating feedback; use of Probabilistic Safety Assessment. The questionnaire was answered by 12 European nuclear power plants, representing 9 different European countries and three different types of reactors (Pressurised Water Reactor, Boiling Water Reactor and Water Water Energy Reactor). Conclusions were drawn under the following headers: Organisational survey and generalities Organisational effectiveness Quality of maintenance Quality of operation Engineering support, management of modification Specific aspects Each analysed subject includes the following topics: Questions background with a summary and the aim of the questions. Current status, that describes common practices, as derived from the answers to the questionnaire, and some examples of good specific practices. Identified good practices. (author)

  8. Exact Outage Probability of Cognitive Underlay DF Relay Networks with Best Relay Selection

    Science.gov (United States)

    Bao, Vo Nguyen Quoc; Duong, Trung Quang

    In this letter, we address the performance analysis of underlay selective decode-and-forward (DF) relay networks in Rayleigh fading channels with non-necessarily identical fading parameters. In particular, a novel result on the outage probability of the considered system is presented. Monte Carlo simulations are performed to verify the correctness of our exact closed-form expression. Our proposed analysis can be adopted for various underlay spectrum sharing applications of cognitive DF relay networks.

  9. Final report of MoReMO 2011-2012. Modelling resilience for maintenance and outage

    International Nuclear Information System (INIS)

    The project Modelling Resilience for Maintenance and Outage (MoReMO) represents a two-year joint effort by VTT Technical Research Centre of Finland, Institute for Energy Technology (IFE, Norway) and Vattenfall (Sweden) to develop and test new approaches for safety management. The overall goal of the project was to present concepts on how resilience can be operationalized and built in a safety critical and socio-technical context. Furthermore, the project also aimed at providing guidance for other organizations that strive to develop and improve their safety performance in a business driven industry. We have applied four approaches in different case studies: Organisational Core Task modelling (OCT), Functional Resonance Analysis Method (FRAM), Efficiency Thoroughness Trade-Off (ETTO) analysis, and Work Practice and Culture Characterisation. During 2011 and 2012 the MoReMO project team has collected data through field observations, interviews, workshops, and document analysis on the work practices and adjustments in maintenance and outage in Nordic NPPs. The project consisted of two sub-studies, one focused on identifying and assessing adjustments and supporting resilient work practices in maintenance activities, while the other focused on handling performance trade-offs in maintenance and outage, as follows: A. Adjustments in maintenance work in Nordic nuclear power plants (VTT and Vattenfall). B. Handling performance trade-offs - the support of adaptive capacities (IFE and Vattenfall). The historical perspective of maintenance and outage management (Chapter 1.1) was provided by Vattenfall. Together, the two sub-studies have provided valuable insights for understanding the rationale behind work practices and adjustments, their effects on resilience, promoting flexibility and balancing between flexibility and reliability. (Author)

  10. Secrecy Cognitive Gain of Cognitive Radio Sensor Networks with Primary Outage Constraint

    OpenAIRE

    Hongyu Ma; Kai Niu; Weiling Wu; Shengyu Li; Guangqian Chu

    2015-01-01

    This paper studies the physical layer security issue for cognitive radio sensor networks (CRSNs) with primary outage constraint, for which a tractable framework is developed to analyze the secrecy performance for CRSNs related to the random channel characteristics, the spatial distributions of nodes, the nearest neighbour routing protocol, and the aggregate interference. Based on stochastic geometry technique, a novel random analysis method is proposed to derive the closed-form expression of ...

  11. Trading wireless information and power transfer: Relay selection to minimize the outage probability

    OpenAIRE

    Butt, M. Majid; Nasir, Adnan; Mohamed, Amr; Guizani, Mohsen

    2014-01-01

    This paper studies the outage probability minimization problem for a multiple relay network with energy harvesting constraints. The relays are hybrid nodes used for simultaneous wireless information and power transfer from the source radio frequency (RF) signals. There is a trade-off associated with the amount of time a relay node is used for energy and information transfer. Large intervals of information transfer implies little time for energy harvesting from RF signals and thus, high probab...

  12. Final report of MoReMO 2011-2012. Modelling resilience for maintenance and outage

    Energy Technology Data Exchange (ETDEWEB)

    Gotcheva, N.; Macchi, L.; Oedewald, P. [Technical Research Centre of Finland (VTT), Espoo (Finland); Eitrheim, M.H.R. [Institute for Energy Technology (IFE) (Norway); Axelsson, C.; Reiman, T.; Pietikaeinen, E. [Ringhals AB (NPP), Vattenfall AB (Sweden)

    2013-04-15

    The project Modelling Resilience for Maintenance and Outage (MoReMO) represents a two-year joint effort by VTT Technical Research Centre of Finland, Institute for Energy Technology (IFE, Norway) and Vattenfall (Sweden) to develop and test new approaches for safety management. The overall goal of the project was to present concepts on how resilience can be operationalized and built in a safety critical and socio-technical context. Furthermore, the project also aimed at providing guidance for other organizations that strive to develop and improve their safety performance in a business driven industry. We have applied four approaches in different case studies: Organisational Core Task modelling (OCT), Functional Resonance Analysis Method (FRAM), Efficiency Thoroughness Trade-Off (ETTO) analysis, and Work Practice and Culture Characterisation. During 2011 and 2012 the MoReMO project team has collected data through field observations, interviews, workshops, and document analysis on the work practices and adjustments in maintenance and outage in Nordic NPPs. The project consisted of two sub-studies, one focused on identifying and assessing adjustments and supporting resilient work practices in maintenance activities, while the other focused on handling performance trade-offs in maintenance and outage, as follows: A. Adjustments in maintenance work in Nordic nuclear power plants (VTT and Vattenfall). B. Handling performance trade-offs - the support of adaptive capacities (IFE and Vattenfall). The historical perspective of maintenance and outage management (Chapter 1.1) was provided by Vattenfall. Together, the two sub-studies have provided valuable insights for understanding the rationale behind work practices and adjustments, their effects on resilience, promoting flexibility and balancing between flexibility and reliability. (Author)

  13. An Extensible Sensing and Control Platform for Building Energy Management

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Anthony [Carnegie Mellon Univ., Pittsburgh, PA (United States); Berges, Mario [Carnegie Mellon Univ., Pittsburgh, PA (United States); Martin, Christopher [Robert Bosch LLC, Anderson, SC (United States)

    2016-04-03

    The goal of this project is to develop Mortar.io, an open-source BAS platform designed to simplify data collection, archiving, event scheduling and coordination of cross-system interactions. Mortar.io is optimized for (1) robustness to network outages, (2) ease of installation using plug-and-play and (3) scalable support for small to large buildings and campuses.

  14. Lights out: Impact of the August 2003 power outage on mortality in New York, NY

    Science.gov (United States)

    Anderson, G. Brooke; Bell, Michelle L.

    2012-01-01

    Background Little is known about how power outages affect health. We investigated mortality effects of the largest US blackout to date, August 14–15, 2003 in New York, NY. Methods We estimated mortality risk in New York, NY, using a generalized linear model with data from 1987–2005. We incorporated possible confounders, including weather and long-term and seasonal mortality trends. Results During the blackout, mortality increased for accidental deaths (122% [95% confidence interval = 28%–287%]) and non-accidental (i.e., disease-related) deaths (25% [12%–41%]), resulting in approximately 90 excess deaths. Increased mortality was not from deaths being advanced by a few days; rather, mortality risk remained slightly elevated through August 2003. Discussion To our knowledge, this is the first analysis of power outages and non-accidental mortality. Understanding the impact of power outages on human health is relevant, given that increased energy demand and climate change are likely to put added strain on power grids. PMID:22252408

  15. Ergodic and Outage Performance of Fading Broadcast Channels with 1-Bit Feedback

    CERN Document Server

    Niu, Bo; Somekh, Oren; Haimovich, Alexander M

    2010-01-01

    In this paper, the ergodic sum-rate and outage probability of a downlink single-antenna channel with K users are analyzed in the presence of Rayleigh flat fading, where limited channel state information (CSI) feedback is assumed. Specifically, only 1-bit feedback per fading block per user is available at the base station. We first study the ergodic sum-rate of the 1-bit feedback scheme, and consider the impact of feedback delay on the system. A closed-form expression for the achievable ergodic sum-rate is presented as a function of the fading temporal correlation coefficient. It is proved that the sum-rate scales as loglogK, which is the same scaling law achieved by the optimal non-delayed full CSI feedback scheme. The sum-rate degradation due to outdated CSI is also evaluated in the asymptotic regimes of either large K or low SNR. The outage performance of the 1-bit feedback scheme for both instantaneous and outdated feedback is then investigated. Expressions for the outage probabilities are derived, along w...

  16. Partner cooperation with decode-and-forward: Closed-form outage analysis and comparison

    KAUST Repository

    Benjillali, Mustapha

    2013-01-01

    In this paper, we investigate the outage performance of "partner cooperation" based on opportunistic Decodeand- Forward with constrained partial selection and reactive relaying strategies in dual-hop cooperative Nakagami-m fading links. The source/destination, which is based on the unique knowledge of local channel state information, selects the best relay to increase the chances of cooperation in both uplink and downlink communications when the direct link is also available. After deriving new expressions for the cumulative distribution functions of the variables of interest, the outage probability of the system is obtained in closed-form. We also derive the ε-outage capacity in different particular cases, and the obtained results - when the channel model is reduced to a Rayleigh fading - either are new or correspond to those previously obtained in other works. Simulation results confirm the accuracy of our analysis for a large selection of system and fading parameters and provide a new insight into the design and optimization of cooperative configurations. © 2012 IEEE.

  17. An Isotropic SPPP Mo del for Femto cells Networks with Outage Probability Constraints

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun; TIAN Hui

    2015-01-01

    Femtocells have been considered as a cost-eff ective solution to unload traffic from already overbur-dened macrocell networks in 4G cellular networks. The severe interference in spectrum-sharing macro and femto networks may cause User-equipment (UE) to experience outage. We derive an utmost isotropic Spatial Poisson point process (SPPP) density for Femtocell access points (FAPs) under the UEs’ outage constraints. Based on the derived isotropic SPPP density, we propose a distributed transmit probability self-regulation scheme for an FAP to adapt its transmit probability per Transmission time in-terval (TTI). The scheme adjusts the homogeneous dis-tributed FAPs in practice deployment to the proposed isotropic one. Simulation results show that the derived den-sity can fulfill the outage probability constraints of UEs while accommodating the maximum femtocells. The self-regulation scheme can adapt the femtocell transmit prob-abilities to provide reliable downlink service, for even a large number of femtocells per cell site.

  18. Distributions of large-scale power outages : extreme values and the effect of truncation

    Energy Technology Data Exchange (ETDEWEB)

    Zeretzki, R.L. [Tenessee Univ., Knoxville, TN (United States). Dept. of Statistics; Briggs, W.M. [New York Methodist Hospital, Brooklyn, NY (United States); Sterling, M. [Oak Ridge Operations, Oak Ridge, TN (United States). Dept. of Energy; Shankar, M. [Oak Ridge National Laboratory, Oak Ridge, TN (United States). Computational Sciences

    2009-07-01

    Studies using complex systems theories have suggested that many power outages follow a power law distribution over certain time scales. In this study, a North American Electric Reliability Council (NERC) database was used to investigate the distribution of large-scale power outages between 1984 and 2006. The aim of the study was to statistically characterize the distribution of outages. Modern statistical methodologies were used to fit the data with various distributions. The statistical theory of extremes was then used to account for the truncation of smaller values in the reporting criteria. Results of the study were then used to investigate the risk management consequences of various tail behaviors. Techniques were developed to fit the actual distribution of the day including log-log rank plots and novel diagnostic plots. A central limit theorem was applied to the log of results in order to produce normalized data. The study showed that immediate investments to increase the reliability of the transmission and distribution network would be beneficial. 24 refs., 2 tabs., 6 figs.

  19. Relay Aided Wireless Multicast Utilizing Network Coding: Outage Behaviour and Diversity Gain

    Directory of Open Access Journals (Sweden)

    Zhi Chen

    2010-01-01

    Full Text Available Broadcast nature of wireless networks can be exploited to provide a flexible transmission, especially in multicast service. The potential relay then is capable to participate in message forwarding. In this paper, we first presents a network coding based cooperative (NCBC multicast scheme exploiting limited feedback, where the source transmits two separate signals to multiple destinations in two successive half slots. The relay may combine the signals if it received two signals correctly and forward it to destinations in the next half slot. The destinations, therefore, can recover signals either from direct transmission or the relay forwarding. The performance analysis on the developed NCBC multicast protocol is given in the viewpoint of physical layer, such as the outage probability and diversity order. It is demonstrated that the NCBC multicast scheme can work better than the source direct multicast in terms of outage probability. Meanwhile, the NCBC multicast scheme can achieve full diversity gain(diversity two for one relay case. Comparing with the known relay schemes, i.e., amplify-andforward (AF and selection decode-and-forward cooperation schemes, it shows that the NCBC multicast scheme achieves almost the same outage performance with relatively less bandwidth and energy consumption.

  20. A novel fusion methodology to bridge GPS outages for land vehicle positioning

    International Nuclear Information System (INIS)

    Many intelligent transportation system applications require accurate, reliable, and continuous vehicle position information whether in open-sky environments or in Global Positioning System (GPS) denied environments. However, there remains a challenging task for land vehicles to achieve such positioning performance using low-cost sensors, especially microelectromechanical system (MEMS) sensors. In this paper, a novel and cost-effective fusion methodology to bridge GPS outages is proposed and applied in the Inertial Navigation System (INS)/GPS/ compass integrated positioning system. In the implementation of the proposed methodology, a key data preprocessing algorithm is first developed to eliminate the noise in inertial sensors in order to provide more accurate information for subsequent modeling. Then, a novel hybrid strategy incorporating the designed autoregressive model (AR model)-based forward estimator (ARFE) with Kalman filter (KF) is presented to predict the INS position errors during GPS outages. To verify the feasibility and effectiveness of the proposed methodology, real road tests with various scenarios were performed. The proposed methodology illustrates significant improvement in positioning accuracy during GPS outages. (paper)

  1. Risk-Based, genetic algorithm approach to optimize outage maintenance schedule

    Energy Technology Data Exchange (ETDEWEB)

    Hadavi, S. Mohammad Hadi [Department of Nuclear Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of)], E-mail: smhadihadavi@yahoo.com

    2008-04-15

    A huge number of components are typically scheduled for maintenance when a nuclear power plant is shut down for its planned outage. Among these components, a number of them are risk significant so that their operability as well as reliability is of prime concern. Lack of proper maintenance for such components during the outage would impose substantial risk on the nuclear power plant (NPP) operation. In this paper, a new approach based on genetic algorithm (GA) is presented for the optimization of the NPP maintenance schedule during plant outage/overhaul, and an optimizer is developed accordingly. The developed optimizer, coupled with the suggested risk-cost model, compromises the cost in favor of maintaining the risk imposed by each schedule below regulatory/industry set limits. The suggested cost model consists of two elements, one considering the cost incurred by maintenance activities and the other incorporating the loss of revenues if needed, but unscheduled component maintenance causes further plant shutdown. The optimizer is developed in such a way that any risk and/or cost models the user desires can be applied. The performance of the developed GA/optimizer is evaluated by comparing its predictions with Monte Carlo simulation results. It is shown that the GA/optimizer performs significantly better.

  2. A heuristic model for risk and cost impacts of plant outage maintenance schedule

    Energy Technology Data Exchange (ETDEWEB)

    Mohammad Hadi Hadavi, S. [Energy Research Inc., 6167 Executive Blvd., Rockville, MD 20852 (United States)], E-mail: smhadihadavi@yahoo.com

    2009-07-15

    Cost and risk are two major competing criteria in maintenance optimization problems. If a plant is forced to shutdown because of accident or fear of accident happening, beside loss of revenue, it causes damage to the credibility and reputation of the business operation. In this paper a heuristic model for incorporating three compelling optimization criteria (i.e., risk, cost, and loss) into a single evaluation function is proposed. Such a model could be used in any evaluation engine of outage maintenance schedule optimizer. It is attempted to make the model realistic and to address the ongoing challenges facing a schedule planner in a simple and commonly understandable fashion. Two simple competing schedules for the NPP feedwater system are examined against the model. The results show that while the model successfully addresses the current challenges for outage maintenance optimization, it properly demonstrates the dynamics of schedule in regards to risk, cost, and losses endured by maintenance schedule, particularly when prolonged outage and lack of maintenance for equipments in need of urgent care are of concern.

  3. Outage Analysis of Cooperative Transmission with Energy Harvesting Relay: Time Switching versus Power Splitting

    Directory of Open Access Journals (Sweden)

    Guanyao Du

    2015-01-01

    Full Text Available This paper investigates the multiuser transmission network with an energy harvesting (EH cooperative relay, where a source transmits independent information to multiple destinations with the help of an energy constrained relay. The relay can harvest energy from the radio frequency (RF signals transmitted from the source, and it helps the multiuser transmission only by consuming the harvested energy. By adopting the time switching and the power splitting relay receiver architectures, we firstly propose two protocols, the time switching cooperative multiuser transmission (TSCMT protocol and the power splitting cooperative multiuser transmission (PSCMT protocol, to enable the simultaneous information processing and EH at the relay for the system. To evaluate the system performance, we theoretically analyze the system outage probability for the two proposed protocols and then derive explicit expressions for each of them, respectively. Numerical results are provided to demonstrate the accuracy of our analytical results and reveal that compared with traditional noncooperative scheme our proposed protocols are green solutions to offer reliable communication and lower system outage probability without consuming additional energy. In particular, for the same transmit power at the source, the PSCMT protocol is superior to the TSCMT protocol to obtain lower system outage probability.

  4. Study on behavior of car and driver in the very small commuter car made of FRP during collision using scale model. Under the consideration of thorax deformation of driver using airbag; FRP sei mokei ni yoru FRP sei chokeiryo jissha shototsuji no kuruma to join no anzensei ni kansuru kenkyu. Kyobu henkei tokusei wo yusuru join ni taisuru air gab no koka

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, H.; Morisawa, M.; Yoshino, T. [Musashi Institute of Technology, Tokyo (Japan); Sato, T. [Keio University, Tokyo (Japan); Ishizuki, H. [Satake Co., Tokyo (Japan)

    1997-10-01

    In this study, after having performed simulation which took up scale models substituting for full scale model of commuter car made of FRP, we carried out collision tests to barrier. Here, we made enquiries about the occupant safety by changing the collision speed and the deformation characteristics of the seat belt, during head-on barrier collision using one-fifth scale models. We sought for the occupant`s safe combinations among the deformation characteristics of airbag and the thorax deformation. In this case, the degree of the occupants injury were estimated using HIC values, 3msecG and maximum deformation of the thorax. 7 refs., 5 figs.

  5. Improvement of availability of PWR nuclear plants through the reduction of the time required for refueling/maintenance outages

    International Nuclear Information System (INIS)

    The objective of the project, conducted by Commonwealth Research Corporation and Westinghouse Electric Corporation, is to identify improvements in procedures and equipment which will reduce the time required for refueling/maintenance outages at PWR nuclear power plants. The outage of Commonwealth Edison Zion Station Unit 1 in March through May of 1976 was evaluated to identify those items which caused delays and those work activities that offer the potential for significant improvements that could reduce the overall duration of the outage and achieve an improvement in the plant's availability for power production. Modifications in procedures have been developed and were evaluated during one or more outages in 1977. Conceptual designs have been developed for equipment modifications to the refueling system that could reduce the time required for the refueling portion of the outage. The purpose of the interim report is to describe those conceptual designs and to assess their impact upon future outages. Recommendations are included for the implementation of these equipment improvements in a continuation of this program as a demonstration of plant availability benefits that can be realized in PWR nuclear plants already in operation or under construction

  6. Long-term durability of the interface in FRP composites after exposure to simulated physiologic saline environments.

    Science.gov (United States)

    Meyer, M R; Friedman, R J; Del Schutte, H; Latour, R A

    1994-10-01

    Fiber/matrix interfacial bond strength significantly influences the mechanical behavior of fiber-reinforced polymer (FRP) composites. Interfacial bond strength durability is therefore particularly important in the development of FRP composites for implant applications where diffused moisture may potentially weaken the material over time. In this study, the long-term durability of interfacial bonding in carbon fiber/380 grade polyetheretherketone (C/PEEK) and carbon fiber/polysulfone (C/PSF) composites was investigated after exposure to hygrothermal environments. A single fiber pull-out test was used to quantitatively determine the ultimate bond strength (UBS) of the samples following exposure. Samples were tested at three temperatures (37, 65, and 95 degrees C) for six time periods (0-5000 h) and in two environments (dry and physiologic saline-immersed). A mathematical model based on nth order chemical reaction kinetics was applied to describe the long-term durability of the interface. The results of this study indicate that interfacial bond strengths in C/PSF and C/PEEK (380 grade) composites are significantly decreased by exposure to physiologic saline and are functions of both time and temperature. For each material, the kinetics of degradation analysis predicts further bond strength losses following initial saturation, which then stabilizes at temperature-dependent equilibrium bond strength levels. PMID:7829551

  7. Compressive Behavior of Four Types FRP Tube Confined Ultra-high-performance Concrete%四种FRP管约束UHPC轴压特性的试验研究

    Institute of Scientific and Technical Information of China (English)

    邓宗才; 刘少新; 王海忠; 陈仲锴

    2015-01-01

    为研究纤维增强聚合物( fiber reinforced polymer, FRP )管约束超高性能混凝土( ultra-high performance concrete, UHPC)的轴压特性,分别对4个未约束和36个约束圆柱体试件进行了轴压试验,测定了应力-应变全曲线,获得了强度和极限应变值。试验结果发现:FRP约束UHPC可明显提高其强度和变形能力,纤维布层数愈多、强度越高,改善效果愈明显;轴压应力-应变曲线为双线性;在相近的约束比下,FRP管约束刚度越小,约束试件的极限应变值越大;已有的强度和极限应变的模型预测值均高于实测值,极限应变预测值偏离试验值更大。本文回归得到了FRP管UHPC的强度和极限应变预测公式预测精度较高。%An axial compression test was conducted to investigate the performance of ultra-high performance concrete ( UHPC) specimens confined with different types and thickness of fiber reinforced polymer ( FRP) tubes. 40 cylindrical specimens were prepared, of which 4 were non-confined while the rest were confined with FRP tubes. Stress-strain curves were produced, and the strength and ultimate strains obtained. The test results show significant enhancement in ultimate strength and strain of UHPC. The confinement effectiveness improves with increase in the FRP layers, and also with increase in strength of FRP. Axial compression stress-strain curves relationship exhibits bilinear characteristics. Under the same confinement ratio, the smaller the stiffness of FRP tube is, the greater the ultimate strain value of the confined specimen becomes. The predicted value of both ultimate strength and strain of existing models is higher than the tested value, and the predicted values of the ultimate strain are more higher than that of the experimental results. The accuracy of the formula for the prediction of strength and ultimate strain of FRP tube confined UHPC specimens suggested in this paper is higher.

  8. 四种FRP管约束UHPC轴压特性的试验研究%Compressive Behavior of Four Types FRP Tube Confined Ultra-high-performance Concrete

    Institute of Scientific and Technical Information of China (English)

    邓宗才; 刘少新; 王海忠; 陈仲锴

    2015-01-01

    为研究纤维增强聚合物( fiber reinforced polymer, FRP )管约束超高性能混凝土( ultra-high performance concrete, UHPC)的轴压特性,分别对4个未约束和36个约束圆柱体试件进行了轴压试验,测定了应力-应变全曲线,获得了强度和极限应变值。试验结果发现:FRP约束UHPC可明显提高其强度和变形能力,纤维布层数愈多、强度越高,改善效果愈明显;轴压应力-应变曲线为双线性;在相近的约束比下,FRP管约束刚度越小,约束试件的极限应变值越大;已有的强度和极限应变的模型预测值均高于实测值,极限应变预测值偏离试验值更大。本文回归得到了FRP管UHPC的强度和极限应变预测公式预测精度较高。%An axial compression test was conducted to investigate the performance of ultra-high performance concrete ( UHPC) specimens confined with different types and thickness of fiber reinforced polymer ( FRP) tubes. 40 cylindrical specimens were prepared, of which 4 were non-confined while the rest were confined with FRP tubes. Stress-strain curves were produced, and the strength and ultimate strains obtained. The test results show significant enhancement in ultimate strength and strain of UHPC. The confinement effectiveness improves with increase in the FRP layers, and also with increase in strength of FRP. Axial compression stress-strain curves relationship exhibits bilinear characteristics. Under the same confinement ratio, the smaller the stiffness of FRP tube is, the greater the ultimate strain value of the confined specimen becomes. The predicted value of both ultimate strength and strain of existing models is higher than the tested value, and the predicted values of the ultimate strain are more higher than that of the experimental results. The accuracy of the formula for the prediction of strength and ultimate strain of FRP tube confined UHPC specimens suggested in this paper is higher.

  9. Outage performance of two-way DF relaying systems with a new relay selection metric

    KAUST Repository

    Hyadi, Amal

    2012-04-01

    This paper investigates a new constrained relay selection scheme for two-way relaying systems where two end terminals communicate simultaneously via a relay. The introduced technique is based on the maximization of the weighted sum rate of both users. To evaluate the performance of the proposed system, the outage probability is derived in a general case (where an arbitrary channel is considered), and then over independently but not necessarily identically distributed (i.n.i.d.) Rayleigh fading channels. The analytical results are verified through simulations. © 2012 IEEE.

  10. MATCASC: A tool to analyse cascading line outages in power grids

    CERN Document Server

    Koç, Yakup; Araujo, Nuno A M; Warnier, Martijn

    2013-01-01

    Blackouts in power grids typically result from cascading failures. The key importance of the electric power grid to society encourages further research into sustaining power system reliability and developing new methods to manage the risks of cascading blackouts. Adequate software tools are required to better analyze, understand, and assess the consequences of the cascading failures. This paper presents MATCASC, an open source MATLAB based tool to analyse cascading failures in power grids. Cascading effects due to line overload outages are considered. The applicability of the MATCASC tool is demonstrated by assessing the robustness of IEEE test systems and real-world power grids with respect to cascading failures.

  11. Exact outage analysis of incremental decode-and-forward opportunistic relaying

    KAUST Repository

    Tourki, Kamel

    2010-11-01

    In this paper, we investigate a dual-hop decode-andforward opportunistic relaying scheme where the selected relay chooses to cooperate only if the source-destination channel is of an unacceptable quality. In our study, we derive exact closed-form expression for the outage probability based on the exact statistics of each hop. Furthermore, we perform asymptotic analysis and we deduce the diversity order of the scheme. We validate our analysis by showing that performance simulation results coincide with our analytical results over different network architectures. © 2010 IEEE.

  12. Algorithms for Estimation of Vehicle Trajectory during GPS Signal Outages Based on Inertial Sensor Data

    Czech Academy of Sciences Publication Activity Database

    Machan, J.; Herda, Z.; Pavelková, Lenka

    Praha: ÚTIA AV ČR, v.v.i, 2011 - (Janžura, M.; Ivánek, J.). s. 19-19 [7th International Workshop on Data - Algorithms - Decision Making. 27.11.2011-29.11.2011, Mariánská] R&D Projects: GA MŠk 1M0572 Institutional research plan: CEZ:AV0Z10750506 Keywords : state-space model * ARX model * uniform noise Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/2011/AS/pavelkova-algorithms for estimation of vehicle trajectory during gps signal outages based on inertial sensor data.pdf

  13. Electrochemical potential monitoring at the Point Lepreau Generating Station during the 2006 maintenance outage

    International Nuclear Information System (INIS)

    Electrochemical corrosion potential (ECP) probes were installed by the Centre for Nuclear Energy Research in the primary heat transport system sample line of the Point Lepreau Generating Station. The probes provided a realistic estimate of the ECP experienced by the outlet feeder pipes during the 2006 maintenance outage and into the start-up. The results from the installation of the probes indicate that the corrosion potential of the probes, and by extension the feeders, is influenced by temperature, flow velocity and the presence of oxidizing species. Changes in the concentration of oxidizing species were shown to significantly alter the measured potential. (author)

  14. Outage and Capacity Performance Evaluation of Distributed MIMO Systems over a Composite Fading Channel

    OpenAIRE

    2014-01-01

    The exact closed-form expressions regarding the outage probability and capacity of distributed MIMO (DMIMO) systems over a composite fading channel are derived. This is achieved firstly by using a lognormal approximation to a gamma-lognormal distribution when a mobile station (MS) in the cell is in a fixed position, and the so-called maximum ratio transmission/selected combining (MRT-SC) and selected transmission/maximum ratio combining (ST-MRC) schemes are adopted in uplink and downlink, res...

  15. Outage and ser performance of an opportunistic multi-user underlay cognitive network

    KAUST Repository

    Khan, Fahd Ahmed

    2012-10-01

    Consider a multi-user underlay cognitive network where multiple cognitive users concurrently share the spectrum with a primary network and a single secondary user is selected for transmission. The channel is assumed to have independent but not identical Nakagami-m fading. Closed form expressions for the outage performance and the symbol-error-rate performance of the opportunistic multi-user secondary network are derived when a peak interference power constraint is imposed on the secondary network in addition to the limited peak transmit power of each secondary user. © 2012 IEEE.

  16. Cognitive multiple-antenna network in outage-restricted primary system

    DEFF Research Database (Denmark)

    Maham, Behrouz; Popovski, Petar

    2013-01-01

    interference from the downlink MISO cognitive radio, also called secondary system. We derive exact expressions for outage probability of the primary user under Rayleigh fading, when the primary system is exposed to interference from a secondary base station. Moreover, in high-SNR scenario, a closed......In the commons model for the spectrum sharing, cognitive users can access the spectrum as long as the target performance in the legitimate primary system is not violated. In this paper, we consider a downlink primary multiple-input-single-output (MISO) system which operates under a controlled...

  17. Integrated planning the key to reducing outage times in the US

    International Nuclear Information System (INIS)

    Start-up and shutdown activities, the carrying out of major modifications, and valve diagnostics/maintenance are among the major causes of unavailability at US Pressurized Water Reactors. If US plant performance is to be lifted to international levels all these will need more attention. However, it may be improved handling of the logistical intricacies of outages which will do more for plant availability in the future. The lengthy (18 or 24 month) operating cycles used by US utilities may complicate plant maintenance; the majority of plants in the world are on 12-month cycles. (author)

  18. Signal Quality Outage Analysis for Ultra-Reliable Communications in Cellular Networks

    DEFF Research Database (Denmark)

    Gerardino, Guillermo Andrés Pocovi; Alvarez, Beatriz Soret; Lauridsen, Mads; Pedersen, Klaus I.; Mogensen, Preben Elgaard

    Ultra-reliable communications over wireless will open the possibility for a wide range of novel use cases and applications. In cellular networks, achieving reliable communication is challenging due to many factors, particularly the fading of the desired signal and the interference. In this regard...... schemes must be complemented with macroscopic diversity as well as interference management techniques in order to ensure the necessary SINR outage performance. Based on the obtained performance results, it is discussed which of the feasible options fulfilling the ultra-reliable criteria are most promising...

  19. Outage and BER analysis for ultrawideband-based WPAN in Nakagami-m fading channels

    KAUST Repository

    Mehbodniya, Abolfazl

    2011-09-01

    This paper presents a performance analysis of multiband orthogonal frequency-division multiplexing (MB-OFDM) in ultra wideband (UWB)-based personal area networks (UPANs). A UPAN consists of devices with different UWB technologies at the physical layer. Approximate expressions for the outage probability and average bit error rate (BER) are derived in closed form for the MB-OFDM target receiver, taking into account multi-user interference (MUI), as well as external interference in the form of time-hopping (TH) and direct-sequence (DS) UWB signals. © 2010 IEEE.

  20. Outage analysis of interference-limited systems using STBC with co-channel MIMO interferers

    Institute of Scientific and Technical Information of China (English)

    Yongzhao LI; Leonard J.CIMINI,JR.; Nageen HIMAYAT

    2009-01-01

    The performance of Space-Time Block Coding (STBC) with co-channel MIMO interference is investigated.For an interference-limited environment, the closed-form ex-pressions for the probability density functions of the signal-to-interference ratio are derived and applied to analyze the outage probability with three typical types of co-channel MIMO interferers: STBC, open-loop spatial multiplexing and closed-loop spatial multiplexing. Both theoretical anal-yses and simulation results show that the performance of STBC is independent of the MIMO modes used in the in-terfering links.

  1. A study on assessment methodology of surveillance test interval and allowed outage time

    Energy Technology Data Exchange (ETDEWEB)

    Che, Moo Seong; Cheong, Chang Hyeon; Lee, Byeong Cheol [Seoul Nationl Univ., Seoul (Korea, Republic of)] (and others)

    1996-07-15

    The objectives of this study is the development of methodology by which assessing the optimizes Surveillance Test Interval(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korea nuclear power plants safety. In the first year of this study, the survey about the assessment methodologies, modeling and results performed by domestic and international researches is performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method.

  2. Feasibility Study for the K-Area Bingham Pump Outage Pit (643-1G)

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, E.R. [Westinghouse Savannah River Company, AIKEN, SC (United States)

    1997-05-01

    The K-Area Bingham Pump Outage Pit (KBPOP) is one of four BPOP areas at Savannah River Site (SRS), collectively referred to as the BPOP waste unit group. This Feasibility Study (FS) of Remedial Alternatives serves as the lead FS for the BPOP waste unit group. This section identifies the purpose and scope of the FS and presents site background information summarized from the Final Remedial Investigation Report with Baseline Risk Assessment (RI/BRA) WSRC-RP- 95-1555, Rev. 1.2 (WSRC 1997).

  3. Psychosocial work strain of maintenance personnel during annual outage and normal operation in a nuclear power plant

    International Nuclear Information System (INIS)

    This paper reports on a study which evaluates psychosocial work demands during the annual outage for a maintenance work group in a nuclear power plant. The study is based on a stress paradigm and it has been asserted that increased work strain would have a negative effect on performance. Nineteen workers, aged 20-55 years, participated in the study. The subjects filled out a questionnaire comparing work strain during annual outage and normal operation. During the outage period a 3-shift 24-hour work schedule, including nightwork, was used (working hours during normal operation was 7-16). Increased demands on concentration and vigilance, increased time pressure and strain on social relations within the group were found to characterize work during annual outage. Interestingly, for specific work tasks an association was found between the risk of making errors and high psychological workload. Increased work strain, shiftwork including nightwork and reduced social support are important psychosocial risk factors that might contribute to human error during the outage period

  4. Research of Effective Width of FRP U-shaped Hoop Reinforcement Properties of Concrete Beams by Shear

    Directory of Open Access Journals (Sweden)

    Li Baokun

    2015-01-01

    Full Text Available The paste fiber reinforced composite material (hereinafter referred to as FRP U-shaped hoop of reinforced concrete beams interfacial debonding is an important reinforcement technology research. For the effective width of the CFRP U-shaped hoop reinforcement, it is still a lack of in-depth research, only relying on the test research huge workload, this article (ANSYS and the numerical simulation in the whole process of the shear load release properties of finite element calculation software. According to the results of finite element analysis, the author studied the CFRP U-shaped hoop to increase the width of the shear capacity of reinforced concrete beams by the impact.

  5. Recent performance of and plasma outage studies with the SNS H{sup −} source

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, M. P., E-mail: stockli@ornl.gov; Han, B.; Murray, S. N.; Pennisi, T. R.; Piller, C.; Santana, M.; Welton, R. [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)

    2016-02-15

    Spallation Neutron Source ramps to higher power levels that can be sustained with high availability. The goal is 1.4 MW despite a compromised radio frequency quadrupole (RFQ), which requires higher radio frequency power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H{sup −} beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ∼55-kW 2-MHz plasma pulses reflecting ∼90% of the continuous ∼300 W, 13-MHz power, which was mitigated with a 4-ms filter for the reflected power signal and an outage resistant, slightly detuned 13-MHz match. Lowering the H{sub 2} gas also increased the H{sup −} beam current to ∼55 mA and increased the RFQ transmission by ∼7% (relative)

  6. Global NDE Best Practice for Technology Improvement, Outage Management, Foreign Material Exclusion and Dose Control

    International Nuclear Information System (INIS)

    Non Destructive Examination (NDE) is a critical element of both Boiling Water and Pressurized Water Reactor outages. Frequently this includes critical path activity so both the utility and the inspection vendor are under intense pressure to perform the work quickly. Concurrent with AREVA's new global organization of NDE resources, AREVA NDE SOLUTIONS, efforts have intensified for global application of lessons learned and best practices. These best practices include new developments as well as continuous improvements to well established tools and NDE techniques. Advancements range from steam generator robots, advanced steam generator deposit characterization sensors and method, new phased array approaches for PWR and BWR reactor vessel examination, new sensors and approaches for RPV head examinations, plus advanced internals examination robots and methods. In addition to specialized tools and techniques, best practice includes numerous management innovations. AREVA's multi-disciplined integrated nuclear worker strategy helps to minimize the total number of personnel deployed to multi-task outages. Specific design and on-site practice has been implemented to minimize or eliminate foreign material from the reactor system and vigorous pursuit of dose management practices keeps our nuclear worker dose as low as reasonably achievable. The industry is moving to much more conservative nuclear worker dose limits. While this is proving to be an issue with many vendors, AREVA has had an internal policy of <2R since 2006. Globalizing the organization also helps AREVA manage peaks and unplanned emergency inspections from an enlarged pool of globally qualified inspection personnel and tools. (Author)

  7. Recent performance of and plasma outage studies with the SNS H⁻ source.

    Science.gov (United States)

    Stockli, M P; Han, B; Murray, S N; Pennisi, T R; Piller, C; Santana, M; Welton, R

    2016-02-01

    Spallation Neutron Source ramps to higher power levels that can be sustained with high availability. The goal is 1.4 MW despite a compromised radio frequency quadrupole (RFQ), which requires higher radio frequency power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H(-) beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ∼55-kW 2-MHz plasma pulses reflecting ∼90% of the continuous ∼300 W, 13-MHz power, which was mitigated with a 4-ms filter for the reflected power signal and an outage resistant, slightly detuned 13-MHz match. Lowering the H2 gas also increased the H(-) beam current to ∼55 mA and increased the RFQ transmission by ∼7% (relative). PMID:26932022

  8. On Outage Probability and Diversity-Multiplexing Tradeoff in MIMO Relay Channels

    CERN Document Server

    Loyka, Sergey

    2011-01-01

    Fading MIMO relay channels are studied analytically, when the source and destination are equipped with multiple antennas and the relays have a single one. Compact closed-form expressions are obtained for the outage probability under i.i.d. and correlated Rayleigh-fading links. Low-outage approximations are derived, which reveal a number of insights, including the impact of correlation, of the number of antennas, of relay noise and of relaying protocol. The effect of correlation is shown to be negligible, unless the channel becomes almost fully correlated. The SNR loss of relay fading channels compared to the AWGN channel is quantified. The SNR-asymptotic diversity-multiplexing tradeoff (DMT) is obtained for a broad class of fading distributions, including, as special cases, Rayleigh, Rice, Nakagami, Weibull, which may be non-identical, spatially correlated and/or non-zero mean. The DMT is shown to depend not on a particular fading distribution, but rather on its polynomial behavior near zero, and is the same ...

  9. Process-analysis by use of system-groups to promote outage performance

    International Nuclear Information System (INIS)

    The paper discusses the use of process analysis and user participation in evaluation and promotion of quality. Two case studies are discussed: outage analysis and a project focused on safety culture in maintenance operation. The authors argue that the system group concept (analysis and problem solving in a group setting, with members from a whole process chain, including management) is a useful tool for quality work. The authors describe the methodology used in the outage analysis and some of the major results. The authors argue that quality work, which underestimates the importance of a process perspective, tends to induce a false belief that minor deviations or difficulties can be seen in isolation from each other. A process perspective clearly shows that even small problems must receive strong attention: what may appear as a minor problem in one part of a process may cause bigger problems in another part. In the second case study, a method for promoting awareness of safety for maintenance operation is discussed

  10. Outage performance analysis of underlay cognitive RF and FSO wireless channels

    KAUST Repository

    Ansari, Imran Shafique

    2014-09-01

    In this work, the outage performance analysis of a dual-hop transmission system composed of asymmetric radio frequency (RF) channel cascaded with a free-space optical (FSO) link is presented. For the RF link, an underlay cognitive network is considered where the secondary users share the spectrum with licensed primary users. Indoor femtocells act as a practical example for such networks. More specifically, it is assumed that the RF link applies power control to maintain the interference at the primary network below a predetermined threshold. While the RF channel is modeled by the Rayleigh fading distribution, the FSO link is modeled by a unified Gamma-Gamma turbulence distribution. The FSO link accounts for pointing errors and both types of detection techniques (i.e. heterodyne detection as well as intensity modulation/direct detection (IM/DD)). With this model, a new exact closed-form expression is derived for the outage probability of the end-To-end signal-To-noise ratio of these systems in terms of the Meijer\\'s G function and the Fox\\'s H functions under fixed amplify-and-forward relay scheme. All new analytical results are verified via computer-based Monte-Carlo simulations and are illustrated by some selected numerical results.

  11. Inducement of IGA/SCC in Inconel 600 steam generator tubing during unit outages

    International Nuclear Information System (INIS)

    The degradation of Unit 4 SG tubing by IGA/SCC has limited both the operating period and end of life predictions for Unit 4 since restart in late 2003. The circumferential IGA/SCC has been most significant in SG4 with substantial increases in both initiation and growth rates from 2005 through the spring of 2007. A detailed review of the occurrence of circumferential OD IGA/SCC at the RTZ in the HL TTS region of Bruce 4 steam generator tubes has led a conclusion that it is probable that the IGA/SCC has been the result of attack by partially reduced sulfur species such as tetrathionates and thiosulfates during periods of low temperature exposure. It is believed that attack of this type has mostly likely occurred during startup evolutions following outages as the result the development of aggressive reduced sulfur species in the TTS region during periods when the boilers were fully drained for maintenance activities. The modification of outage practices to limit secondary side oxygen ingress in the spring of 2007 has apparently arrested the degradation and has had significant affects on the allowable operating interval and end of life predictions for the entire unit. (author)

  12. Outage Analysis of Practical FSO/RF Hybrid System With Adaptive Combining

    KAUST Repository

    Rakia, Tamer

    2015-08-01

    Hybrid free-space optical (FSO)/radio-frequency (RF) systems have emerged as a promising solution for high-data-rate wireless transmission. We present and analyze a transmission scheme for the hybrid FSO/RF communication system based on adaptive combining. Specifically, only FSO link is active as long as the instantaneous signal-to-noise ratio (SNR) at the FSO receiver is above a certain threshold level. When it falls below this threshold level, the RF link is activated along with the FSO link and the signals from the two links are combined at the receiver using a dual-branch maximal ratio combiner. Novel analytical expression for the cumulative distribution function (CDF) of the received SNR for the proposed hybrid system is obtained. This CDF expression is used to study the system outage performance. Numerical examples are presented to compare the outage performance of the proposed hybrid FSO/RF system with that of the FSO-only and RF-only systems. © 1997-2012 IEEE.

  13. Spatial generalized linear mixed models of electric power outages due to hurricanes and ice storms

    International Nuclear Information System (INIS)

    This paper presents new statistical models that predict the number of hurricane- and ice storm-related electric power outages likely to occur in each 3 kmx3 km grid cell in a region. The models are based on a large database of recent outages experienced by three major East Coast power companies in six hurricanes and eight ice storms. A spatial generalized linear mixed modeling (GLMM) approach was used in which spatial correlation is incorporated through random effects. Models were fitted using a composite likelihood approach and the covariance matrix was estimated empirically. A simulation study was conducted to test the model estimation procedure, and model training, validation, and testing were done to select the best models and assess their predictive power. The final hurricane model includes number of protective devices, maximum gust wind speed, hurricane indicator, and company indicator covariates. The final ice storm model includes number of protective devices, ice thickness, and ice storm indicator covariates. The models should be useful for power companies as they plan for future storms. The statistical modeling approach offers a new way to assess the reliability of electric power and other infrastructure systems in extreme events

  14. Report on Nova Scotia Power Company's transmission system and outages communications

    Energy Technology Data Exchange (ETDEWEB)

    Stright, R.; Cannata, M.D.Jr.; Lautenschlager, M.; Kozlosky, C.K.; Arndt, S.M. [Liberty Consulting Group, Quentin, PA (United States)

    2005-03-04

    A severe storm occurred in Nova Scotia on November 13 and 14, 2004, during which a large portion of Nova Scotia Power Inc. (NSPI) customers were without power. The storm severely damaged sections of Nova Scotia's power transmission and distribution systems. The Nova Scotia Utility and Review Board issued a request for proposals (RFP) for consultants to examine NSPI's communications as well as its transmission system operations, maintenance and planning. The Liberty Consulting Group conducted the study and reported on transmission system maintenance and structure design; transmission system planning and system design; and communications and outage response. The consultant field inspected the adequacy of design criteria and the condition of failed and remaining towers and poles in areas affected by the storm and compared results with areas not affected by the storm. The consultant also evaluated NSPI's maintenance and inspection programs, vegetation management, staffing, replacement structure inventory and lessons learned from previous weather events. The report revealed how the collapse of a small number of transmission towers resulted in such a major outage. Following the review, 74 actions were created, of which more than half are complete. tabs, figs.

  15. Exploiting Outage and Error Probability of Cooperative Incremental Relaying in Underwater Wireless Sensor Networks

    Science.gov (United States)

    Nasir, Hina; Javaid, Nadeem; Sher, Muhammad; Qasim, Umar; Khan, Zahoor Ali; Alrajeh, Nabil; Niaz, Iftikhar Azim

    2016-01-01

    This paper embeds a bi-fold contribution for Underwater Wireless Sensor Networks (UWSNs); performance analysis of incremental relaying in terms of outage and error probability, and based on the analysis proposition of two new cooperative routing protocols. Subject to the first contribution, a three step procedure is carried out; a system model is presented, the number of available relays are determined, and based on cooperative incremental retransmission methodology, closed-form expressions for outage and error probability are derived. Subject to the second contribution, Adaptive Cooperation in Energy (ACE) efficient depth based routing and Enhanced-ACE (E-ACE) are presented. In the proposed model, feedback mechanism indicates success or failure of data transmission. If direct transmission is successful, there is no need for relaying by cooperative relay nodes. In case of failure, all the available relays retransmit the data one by one till the desired signal quality is achieved at destination. Simulation results show that the ACE and E-ACE significantly improves network performance, i.e., throughput, when compared with other incremental relaying protocols like Cooperative Automatic Repeat reQuest (CARQ). E-ACE and ACE achieve 69% and 63% more throughput respectively as compared to CARQ in hard underwater environment. PMID:27420061

  16. Exploiting Outage and Error Probability of Cooperative Incremental Relaying in Underwater Wireless Sensor Networks.

    Science.gov (United States)

    Nasir, Hina; Javaid, Nadeem; Sher, Muhammad; Qasim, Umar; Khan, Zahoor Ali; Alrajeh, Nabil; Niaz, Iftikhar Azim

    2016-01-01

    This paper embeds a bi-fold contribution for Underwater Wireless Sensor Networks (UWSNs); performance analysis of incremental relaying in terms of outage and error probability, and based on the analysis proposition of two new cooperative routing protocols. Subject to the first contribution, a three step procedure is carried out; a system model is presented, the number of available relays are determined, and based on cooperative incremental retransmission methodology, closed-form expressions for outage and error probability are derived. Subject to the second contribution, Adaptive Cooperation in Energy (ACE) efficient depth based routing and Enhanced-ACE (E-ACE) are presented. In the proposed model, feedback mechanism indicates success or failure of data transmission. If direct transmission is successful, there is no need for relaying by cooperative relay nodes. In case of failure, all the available relays retransmit the data one by one till the desired signal quality is achieved at destination. Simulation results show that the ACE and E-ACE significantly improves network performance, i.e., throughput, when compared with other incremental relaying protocols like Cooperative Automatic Repeat reQuest (CARQ). E-ACE and ACE achieve 69% and 63% more throughput respectively as compared to CARQ in hard underwater environment. PMID:27420061

  17. Analytical Tools to Predict Distribution Outage Restoration Load. Final Project Report.

    Energy Technology Data Exchange (ETDEWEB)

    Law, John

    1994-11-14

    The main activity of this project has been twofold: (1) development of a computer model to predict CLPU(Cold Load Pickup) and (2) development of a field measurement and analysis method to obtain the input parameters of the CLPU model. The field measurement and analysis method is called the Step-Voltage-Test (STEPV). The Kootenai Electric Cooperative Appleway 51 feeder in Coeur d`Alene was selected for analysis in this project and STEPV tests were performed in winters of 92 and 93. The STEPV data was analyzed (method and results presented within this report) to obtain the Appleway 51 feeder parameters for prediction by the CLPU model. One only CLPU record was obtained in winter 1994. Unfortunately, the actual CLPU was not dramatic (short outage and moderate temperature) and did not display cyclic restoration current. A predicted Appleway 51 feeder CLPU was generated using the parameters obtained via the STEPV measurement/analysis/algorithm method at the same ambient temperature and outage duration as the measured actual CLPU. The predicted CLPU corresponds reasonably well with the single actual CLPU data obtained in winter 1994 on the Appleway 51 feeder.

  18. Key issues for the control of refueling outage duration and costs in PWR nuclear power plants

    International Nuclear Information System (INIS)

    For several years, EDF, within the framework of the CIDEM project and in collaboration with some German Utilities, has undertaken a detailed review of the operating experience both of its own NPP and of foreign units, in order to improve the performances of future units under design, particularly the French-German European Pressurized Reactor (EPR) project. This review made it possible to identify the key issues allowing to decrease the duration of refueling and maintenance outages. These key issues can be classified in 3 categories: Design; Maintenance and Logistic Support; Outage Management. Most key issues in the design field and some in the logistic support field have been studied and could be integrated into the design of any future PWR unit, as for the EPR project. Some of them could also be adapted to current plants, provided they are feasible and profitable. The organization must be tailored to each country, utility or period: it widely depends on the power production environment, particularly in a deregulation context. (author)

  19. Outage probability of dual-hop partial relay selection with feedback delay in the presence of interference

    KAUST Repository

    Al-Qahtani, Fawaz S.

    2011-09-01

    In this paper, we investigate the outage performance of a dual-hop relaying systems with partial relay selection and feedback delay. The analysis considers the case of Rayleigh fading channels when the relaying station as well as the destination undergo mutually independent interfering signals. Particularly, we derive the cumulative distribution function (c.d.f.) of a new type of random variable involving sum of multiple independent exponential random variables, based on which, we present closed-form expressions for the exact outage probability of a fixed amplify-and-forward (AF) and decode-and-forward (DF) relaying protocols. Numerical results are provided to illustrate the joint effect of the delayed feedback and co-channel interference on the outage probability. © 2011 IEEE.

  20. Outage performance of opportunistic two-way amplify-and-forward relaying with outdated channel state information

    KAUST Repository

    Hwang, Kyusung

    2013-09-01

    In this paper, we study the outage performance of an amplify-and-forward (AF)-based two-way relaying (TWR) system with multiple relays where a single relay selection is performed based on outdated channel state information (CSI). Specifically, we propose a single relay selection scheme in AF-based TWR system under outdated CSI conditions. With this policy, we offer a statistical analysis of the signal-to-noise ratio per hop and analyze the outage probability with asymmetric outage thresholds based on CSI-assisted AF protocol. Additionally, we provide the exact and asymptotic expressions based on the provided statistical/joint statistical analyses of a dual-hop AF transmission. Finally, we verify our analytical results with some selected computer-based simulation results. © 1972-2012 IEEE.

  1. Innovation on Energy Power Technology (15)Great Advances in Power System Stabilizing Technology triggered by the Wide-area Outage

    Science.gov (United States)

    Egawa, Masanao

    On July 23, 1987, a very hot day, the largest wide-area power outage occurred in Kanto-Area, Japan. The cause was a voltage collapse on the bulk power network of Tokyo Electric Power Company, due to the abnormal rate of demand rising following resume after lunch break. Aggressive studies on voltage collapse throughout industry and university have led to great advances in power system stability. This essay describes the detail record of the outage, the applied countermeasures, and the inside story when the multiple voltage solutions of power flow on actual power system were found out for the first time.

  2. Outage performance improvement by state of the art reactor stud tensioning

    International Nuclear Information System (INIS)

    Actual methods of reactor closing, i.e. cover to vessel sealing, is based on the creation of an equal load to the sealing circumference by tensioning all reactor studs with an equal force. This method ensures leak tightness through equal compression of the reactor seal in normal circumstances and is largely applied for all types of reactors throughout many generations and designs of nuclear power stations. The tension generated in each reactor stud is controlled indirectly by measuring the reactor stud elongation while under stress. Most studs are designed to measure this elongation easily by conventional or more advanced systems (from individual clock gauge to integrated digital transmission to a computer screen). It is this elongation value, prescribed by the reactor vessel/cover manufacturer which must be respected and demonstrated during all reactor closing operations, weather they take place for initial hydro testing, refuelling operations or periodical hydraulic tests of the primary circuit. Closing (and re-opening) of reactor vessels has become a routine operation as it is required for fuel reloading of the reactor core. This operation is performed on all PWR and BWR type of reactors with a large variety of tooling. As most of the utilities have implemented maintenance optimisation programs, the refuelling outage is reduced to a sequence of activities that allow quick and efficient refuelling of the core. The performance and efficiency of instrumentation and tooling deployed during these essential activities are of the utmost importance to minimise the critical path of the refuelling outage. Today, in support of outage performance, many utilities have invested in new and refurbished tooling to allow quick and efficient opening and closing of the reactor vessel. The features and properties of the most performing multi stud tensioning machines currently in service in nuclear power stations world wide (Africa, Europe, Asia and USA) are presented in the paper

  3. Outage performance improvement by state of the art reactor stud tensioning

    Energy Technology Data Exchange (ETDEWEB)

    Oehler, Horst Werner [Wenutec GmbH, Industriestrasse 1, D-44534 Luenen (Germany); Vervliet, Herman [Wenutec Sarl, 2, Parc des Fontenelles, F-78870 Bailly (France)

    2006-07-01

    Actual methods of reactor closing, i.e. cover to vessel sealing, is based on the creation of an equal load to the sealing circumference by tensioning all reactor studs with an equal force. This method ensures leak tightness through equal compression of the reactor seal in normal circumstances and is largely applied for all types of reactors throughout many generations and designs of nuclear power stations. The tension generated in each reactor stud is controlled indirectly by measuring the reactor stud elongation while under stress. Most studs are designed to measure this elongation easily by conventional or more advanced systems (from individual clock gauge to integrated digital transmission to a computer screen). It is this elongation value, prescribed by the reactor vessel/cover manufacturer which must be respected and demonstrated during all reactor closing operations, weather they take place for initial hydro testing, refuelling operations or periodical hydraulic tests of the primary circuit. Closing (and re-opening) of reactor vessels has become a routine operation as it is required for fuel reloading of the reactor core. This operation is performed on all PWR and BWR type of reactors with a large variety of tooling. As most of the utilities have implemented maintenance optimisation programs, the refuelling outage is reduced to a sequence of activities that allow quick and efficient refuelling of the core. The performance and efficiency of instrumentation and tooling deployed during these essential activities are of the utmost importance to minimise the critical path of the refuelling outage. Today, in support of outage performance, many utilities have invested in new and refurbished tooling to allow quick and efficient opening and closing of the reactor vessel. The features and properties of the most performing multi stud tensioning machines currently in service in nuclear power stations world wide (Africa, Europe, Asia and USA) are presented in the paper

  4. Single nucleotide polymorphisms in sFRP4 are associated with bone and body composition related parameters in Danish but not in Belgian men

    DEFF Research Database (Denmark)

    Boudin, Eveline; Piters, Elke; Nielsen, Torben Leo;

    2012-01-01

    replicate the results found in the Danish cohort but we found one SNP (rs2598116) associated with height. In conclusion, genetic variation in sFRP4 has an influence on hip fracture risk, percentage body fat and height in a Danish male population. However, we were unable to replicate these results in an......) in a decrease in bone density and bone strength. Finally, we observed in the Danish population age specific associations with height and fat mass. In the Belgian population we tried to replicate the results of three SNPs with BMD and body composition parameters. Unfortunately, we were not able to...... populations. Based on these data we decided to perform an association study between common variants in sFRP4, BMD, hip geometry parameters and body composition parameters in a population consisting of 1383 Danish men (783 aged 20-29 years; 600 aged 60-74 years). Afterwards we tried to replicate the...

  5. Accurate outage analysis of incremental decode-and-forward opportunistic relaying

    KAUST Repository

    Tourki, Kamel

    2011-04-01

    In this paper, we investigate a dual-hop decode-and-forward opportunistic relaying scheme where the selected relay chooses to cooperate only if the source-destination channel is of an unacceptable quality. We first derive the exact statistics of received signal-to-noise (SNR) over each hop with co-located relays, in terms of probability density function (PDF). Then, the PDFs are used to determine very accurate closed-form expression for the outage probability for a transmission rate R. Furthermore, we perform asymptotic analysis and we deduce the diversity order of the scheme. We validate our analysis by showing that performance simulation results coincide with our analytical results over different network architectures. © 2011 IEEE.

  6. On the Outage Behavior of Asynchronous OFDM DF and AF Cooperative Networks

    CERN Document Server

    Torbatian, Mehdi

    2009-01-01

    The outage behavior of various relaying protocols over a general one hop asynchronous cooperative network is examined when orthogonal frequency division multiplexing (OFDM) is used to combat synchronization error among the relays. We consider non-orthogonal selection decode-and-forward (NSDF), orthogonal selection decode-and-forward (OSDF), non-orthogonal amplify-and-forward (NAF), and orthogonal amplify-and-forward (OAF) relaying protocols and analyze the diversity multiplexing gain tradeoff (DMT) in all scenarios. The transmitting nodes cooperatively construct an asynchronous OFDM space-time code by re-sending the source messages over a common time interval and a common frequency bandwidth. It is shown that in decode-and-forward (DF) type protocols, the asynchronous network provides a diversity gain greater than or equal to the one of the corresponding synchronous network in the limit of code word length and throughout the range of multiplexing gain. In amplify-and-forward (AF) type protocols, in which the ...

  7. Mathematical model for planning measures to reduce coal face outages in mines

    Energy Technology Data Exchange (ETDEWEB)

    Litvintsev, A.V.

    1987-05-01

    Describes with detailed examples the TISPLAN SUP OZSh computer program which has been developed for use by mine management (supervisors and mechanics) and comprises two main subsets, managerial and mechanical. The full set of causes of coal face outages is determined using the classifiers currently used by the Soviet coal industry (217 causes). This model was assessed in data processing and computer centers belonging to the Donetskugol' and Oktyabr'ugol' associations and its largest drawback was found to be the laboriousness of the preventive measure calculations; this may be corrected by improving the reliability of the primary data in the data base of preventive measures, with objective assessments of their effectiveness and details of the level of staff training. The minimum annual benefit of introducing this computerized calculation system will be 6,000 rubles per mine. 4 refs.

  8. QA's role in the independent verification of plant readiness for startup from planned outages

    International Nuclear Information System (INIS)

    Quality Assurance (QA) personnel at the N Reactor, located near Richland, Washington, USA, perform many activities to independently verify the readiness for startup of the reactor from planned outages. The verifications are performed as inspections, test witnessing, audits, surveillance, and followup on identified corrective action needs. The results of these verifications are used in a formal readiness review process. The formal reviews are administered by a Review Board of representatives from several major components of the Company and are conducted using systematically structured analytical techniques. The N Reactor QA staff includes 26 persons (excluding managers) who are involved in independent verifications of reactor-related work as part or all of their assigned functions

  9. Outage Performance Analysis of Cooperative Diversity with MRC and SC in Correlated Lognormal Channels

    Directory of Open Access Journals (Sweden)

    Skraparlis D

    2009-01-01

    Full Text Available Abstract The study of relaying systems has found renewed interest in the context of cooperative diversity for communication channels suffering from fading. This paper provides analytical expressions for the end-to-end SNR and outage probability of cooperative diversity in correlated lognormal channels, typically found in indoor and specific outdoor environments. The system under consideration utilizes decode-and-forward relaying and Selection Combining or Maximum Ratio Combining at the destination node. The provided expressions are used to evaluate the gains of cooperative diversity compared to noncooperation in correlated lognormal channels, taking into account the spectral and energy efficiency of the protocols and the half-duplex or full-duplex capability of the relay. Our analysis demonstrates that correlation and lognormal variances play a significant role on the performance gain of cooperative diversity against noncooperation.

  10. A unified simulation approach for the fast outage capacity evaluation over generalized fading channels

    KAUST Repository

    Ben Rached, Nadhir

    2015-06-14

    The outage capacity (OC) is among the most important performance metrics of communication systems over fading channels. The evaluation of the OC, when Equal Gain Combining (EGC) or Maximum Ratio Combining (MRC) diversity techniques are employed, boils down to computing the Cumulative Distribution Function (CDF) of the sum of channel envelopes (equivalently amplitudes) for EGC or channel gain (equivalently squared enveloped/amplitudes) for MRC. Closed-form expressions of the CDF of the sum of many generalized fading variates are generally unknown and constitute open problems. In this paper, we develop a unified hazard rate twisting Importance Sampling (IS) based approach to efficiently estimate the CDF of the sum of independent arbitrary variates. The proposed IS estimator is shown to achieve an asymptotic optimality criterion, which clearly guarantees its efficiency. Some selected simulation results are also shown to illustrate the substantial computational gain achieved by the proposed IS scheme over crude Monte-Carlo simulations.

  11. Experience of oil in CANDU® moderator during A831 planned outage at Bruce Power

    International Nuclear Information System (INIS)

    In their address to the Nuclear Plant Chemistry Conference 2009, Bruce Power staff will describe the effects of oil ingress to the moderator of a CANDU® reactor. During the A831 planned outage of Bruce Power Unit 3, an incident of oil ingress into moderator was discovered on Oct 17, 2008. An investigation identified the cause of the oil ingress. Atomic Energy of Canada Ltd. (AECL) assessed operability of the reactor with the oil present and made recommendations with respect to the effect on unit start-up with oil present. The principal concern was the radiolytic generation of deuterium from the breakdown of the oil in-core. Various challenges were presented during start-up which were overcome via innovative approaches. The subsequent actions and consequential effects on moderator chemistry are discussed in this paper. Examination of the plant chemistry data revealed some interesting aspects of moderator system chemistry under upset conditions which will also be presented. (author)

  12. Experience of oil in CANDU moderator during A831 planned outage at Bruce Power

    International Nuclear Information System (INIS)

    In their address to the Nuclear Plant Chemistry Conference 2009, Bruce Power staff will describe the effects of oil ingress to the moderator of a CANDU reactor. During the A831 planned outage of Bruce Power Unit 3, an incident of oil ingress into moderator was discovered on Oct 17, 2008. An investigation identified the cause of the oil ingress. Atomic Energy of Canada Ltd. (AECL) assessed operability of the reactor with the oil present and made recommendations with respect to the effect on unit start-up with oil present. The principal concern was the radiolytic generation of deuterium from the breakdown of the oil in-core. Various challenges were presented during start-up which were overcome via innovative approaches. The subsequent actions and consequential effects on moderator chemistry are discussed in this paper. Examination of the plant chemistry data revealed some interesting aspects of moderator system chemistry under upset conditions which will also be presented. (author)

  13. Start-up of Cirus after refurbishment outage and observations during approach to criticality

    International Nuclear Information System (INIS)

    The report presents various physics related aspects of the startup of Cirus reactor after the prolonged refurbishment outage. The special nuclear instrumentation scheme adopted to ensure safe startup of the reactor is described. Salient observations made and physics measurements carried out during various approaches to criticality are covered. One of the significant observations concerned a major reactivity anomaly during the approach to criticality. After due investigations the cause of the anomaly was attributed to the inadvertent wetting of the graphite reflector which houses the reactor regulating and protection system ion chambers. The report also includes salient observations during raising of reactor power to high levels. The wet reflector also resulted in a significant difference measured between the thermal and neutronic power of the reactor. In view of the reactivity anomaly, the core reactivity variation with time was closely followed and compared with computations. As expected the reactivity anomaly reduced gradually with time. (author)

  14. Outage Key Safety Functions Configuration risk assessment for a three loops Westinghouse PWR

    International Nuclear Information System (INIS)

    Highlights: • The paper evaluates the use of PSA on the Outage configuration risk management. • A method is proposed based on Risk Criteria to evaluate the OKSFs’ Configurations. • The methodology allows to identify which of the OKSFs can be analyzed using PSA. • The method has been applied to a Pilot real case. The OKSFs procedure is evaluated. - Abstract: The methodology developed provides guidance on the use of Probabilistic Safety Assessment (PSA) for the risk-informed evaluation of Guides which ensure the compliment of Outage Key Safety Functions (OKSFs) in Nuclear Power Plants. The methodology has been applied to the 3rd and 13th Plant Operational States (POSs) as a pilot experience. These POSs are within the Operating Mode 4 (Hot Shutdown) of a three loops Westinghouse Pressurized Water Reactor. The addressed Guide requires the operability of just one charge pump as boric acid supply source. PSA gives a Core Damage Frequency increase (ΔCDF) of 1.19 × 10−6 year−1 for the unavailability of the charge pump in standby, consequently, the maximum exposure time (time for the Increase of Core Damage Probability of the configuration to reach 1.0E−06) for this situation is T = 53.6 h. Given an average time for the POSs of 40 h, it is concluded that the charge pumps requirement is correct. However, it could be improved with the inclusion of an additional inventory replacement function. This would limit the effect on risk of the charge pump unavailability. Furthermore, the need for the external electrical sources to be available during Mode 4 is ratified. The procedure requires the operability of both supply sources during the POSs. The unavailability of one of supply sources them involves a ΔCDF equal to 1.64 × 10−5 year−1 and a maximum exposure time of T = 3.89 h. This requirement is considered appropriate from the risk-informed regulation point of view

  15. Unified Importance Sampling Schemes for Efficient Simulation of Outage Capacity over Generalized Fading Channels

    KAUST Repository

    Ben Rached, Nadhir

    2015-11-13

    The outage capacity (OC) is among the most important performance metrics of communication systems operating over fading channels. Of interest in the present paper is the evaluation of the OC at the output of the Equal Gain Combining (EGC) and the Maximum Ratio Combining (MRC) receivers. In this case, it can be seen that this problem turns out to be that of computing the Cumulative Distribution Function (CDF) for the sum of independent random variables. Since finding a closedform expression for the CDF of the sum distribution is out of reach for a wide class of commonly used distributions, methods based on Monte Carlo (MC) simulations take pride of price. In order to allow for the estimation of the operating range of small outage probabilities, it is of paramount importance to develop fast and efficient estimation methods as naive Monte Carlo (MC) simulations would require high computational complexity. In this line, we propose in this work two unified, yet efficient, hazard rate twisting Importance Sampling (IS) based approaches that efficiently estimate the OC of MRC or EGC diversity techniques over generalized independent fading channels. The first estimator is shown to possess the asymptotic optimality criterion and applies for arbitrary fading models, whereas the second one achieves the well-desired bounded relative error property for the majority of the well-known fading variates. Moreover, the second estimator is shown to achieve the asymptotic optimality property under the particular Log-normal environment. Some selected simulation results are finally provided in order to illustrate the substantial computational gain achieved by the proposed IS schemes over naive MC simulations.

  16. Risk quantification in deterministic procedures: outage key safety functions evaluation using probabilistic risk assessment

    International Nuclear Information System (INIS)

    In 2007 a collaboration agreement between the Nuclear Industry and the Nuclear Engineering Research Group of the Technical University of Catalonia (NERG-UPC) began on the Risk-Informed Operation Decision Management field. A Manual has been created; it provides a guidance of the systematic of using Probabilistic Risk Assessment for the evaluation of guides or procedures which ensure the compliment of Outage Key Safety Functions (OKSF) in nuclear power plants. The evaluation base is probabilistic; the core damage frequencies (CDF) values determine the acceptance of the analyzed guides and encourage suggestions for improvements in the contained procedures. Acceptance criteria from Plants Supervision System are used throw out quantifications. The developed methodology pretends to evaluate the risk associated to the availability system configurations during the outage. The documents used in the development have been: PRA, OKSF procedure and Performance Technical Specifications (PTS) from a 3 loops Westinghouse PWR. As a pilot experience, the methodology has been applied to the 3. and 13. Operational Plant State (OPS), always within the operational mode 4. Some conclusions of the analysis: The analyzed procedure requires the operability of just one charge pump as boric acid supply source. PRA gives a CDF increase (ΔCDF) of 1,19.10-6 year-1 for the pump in standby, consequently, an exposure time T= 53,6 hours. Given an average time for the OPS of 40 hours, it is concluded the correct treatment of the procedure. However, it could be improved with the inclusion of an additional inventory replacement function. This would limit the charge pump unavailability. On the other hand, the availability of the external electrical sources is ratified. The procedure requires the operability of both supplies during the OPS. The unavailability of one of them (transformer fail) involves a ΔCDF equal to 1,64.10-5 year-1 and a T= 3,89 hours. Then, it is considered appropriate the treatment

  17. Binding of sFRP-3 to EGF in the extra-cellular space affects proliferation, differentiation and morphogenetic events regulated by the two molecules

    OpenAIRE

    R. Scardigli; Cargiolo, C; Tosoni, D.; Borello, U; Sampaolesi, Maurilio; Sciorati, C.; Cannata, S.; E. Clementi; Brunelli, S.; Cossu, G.

    2008-01-01

    Background sFRP-3 is a soluble antagonist of Wnts, widely expressed in developing embryos. The Wnt gene family comprises cysteine-rich secreted ligands that regulate cell proliferation, differentiation, organogenesis and oncogenesis of different organisms ranging from worms to mammals. In the canonical signal transduction pathway Wnt proteins bind to the extracellular domain of Frizzled receptors and consequently recruit Dishevelled (Dsh) to the cell membrane. In addition to Wnt membrane rece...

  18. Analysis on Adhesively-Bonded Joints of FRP-steel Composite Bridge under Combined Loading: Arcan Test Study and Numerical Modeling

    OpenAIRE

    Xu Jiang; Xuhong Qiang; Henk Kolstein; Frans Bijlaard

    2016-01-01

    The research presented in this paper is an experimental study and numerical analysis on mechanical behavior of the adhesively-bonded joint between FRP sandwich bridge deck and steel girder. Generally, there are three typical stress states in the adhesively-bonded joint: shear stress, tensile stress, and combination of both. To realize these stress states in the adhesively-bonded joint during tests, a specific loading device is developed with the capacity of providing six different loading ang...

  19. Structure-function relationship of Vibrio harveyi NADPH-flavin oxidoreductase FRP: essential residues Lys167 and Arg15 for NADPH binding.

    Science.gov (United States)

    Chung, Hae-Won; Tu, Shiao-Chun

    2012-06-19

    Vibrio harveyi NADPH-FMN oxidoreductase (FRP) catalyzes flavin reduction by NADPH. In comparing amino acid sequence and crystal structure with Escherichia coli NfsA, residues N134, R225, R133, K167, and R15 were targeted for investigation of their possible roles in the binding and utilization of the NADPH substrate. By mutation of each of these five residues to an alanine, steady-state rate analyses showed that the variants K167A and R15A had apparently greatly increased K(m,NADPH) and reduced k(cat)/K(m,NADPH), whereas little or much more modest changes were found for the other variants. The deuterium isotope effects (D)(V/K) for (4R)-[4-(2)H]-NADPH were markedly increased to 6.3 and 7.4 for K167A and R15A, respectively, indicating that the rate constants for NADPH and NADP(+) dissociation were greatly enhanced relative to the hydride transfer steps. Also, anaerobic stopped-flow analyses revealed that the equilibrium dissociation constant for NADPH binding (K(d)) to be 2.5-3.9 and 1.1 mM for K167A and R15A, respectively, much higher than the 0.4 μM K(d) for the native FRP, whereas the k(cat) of these two variants were similar to that of the wild-type enzyme. Moreover, the K167 to alanine mutation led to even a slight increase in k(cat)/K(m) for NADH. These results, taken together, provide a strong support to the conclusion that K167 and R15 each was critical in the binding of NADPH by FRP. Such a functional role may also exist for other FRP homologous proteins. PMID:22650604

  20. WNT signaling enhances breast cancer cell motility and blockade of the WNT pathway by sFRP1 suppresses MDA-MB-231 xenograft growth

    OpenAIRE

    Matsuda, Yutaka; Schlange, Thomas; Oakeley, Edward J.; Boulay, Anne; Nancy E Hynes

    2009-01-01

    Introduction In breast cancer, deregulation of the WNT signaling pathway occurs by autocrine mechanisms. WNT ligands and Frizzled receptors are coexpressed in primary breast tumors and cancer cell lines. Moreover, many breast tumors show hypermethylation of the secreted Frizzled-related protein 1 (sFRP1) promoter region, causing low expression of this WNT antagonist. We have previously shown that the WNT pathway influences proliferation of breast cancer cell lines via activation of canonical ...

  1. Assessment of the impact on safety with regard to change in outage interval from 12 to 18 or 24 months at Gentilly-2 Nuclear Generating Station

    Energy Technology Data Exchange (ETDEWEB)

    Vaillancourt, R.; Croteau, M.; Komljenovic, D.; Royer, M. [Hydro-Quebec, Montreal, Quebec (Canada); Bellil, A.; Joober, K. [ENAQ, (Canada); Abdul-Nour, G.; Darragi, M. [Univ. of Quebec in Trois-Rivieres, Trois-Rivieres, Quebec (Canada)

    2003-07-01

    This paper presents the methodology and preliminary results of an impact assessment, concerning safety, resulting from the increase in outage interval from 12 to 18 or 24 months at Gentilly-2 NPP. This change will result in the decrease of the frequency of periodic tests and preventive maintenance performed during planned outages, and modify safety design matrices and reliability studies results and conclusions. (author)

  2. Specific in vivo binding in the rat brain of [18F]RP 62203: A selective 5-HT2A receptor radioligand for positron emission tomography

    International Nuclear Information System (INIS)

    In vivo pharmacokinetic and brain binding characteristics of [18F]RP 62203, a selective high-affinity serotonergic 5-HT2A receptor antagonist, were assessed in the rat following intravenous injection of trace amount of the radioligand. The radioactive distribution profile observed in the brain 60 min after injection was characterized by greater than fourfold higher uptake in neocortex as compared to cerebellum (0.38 ± 0.07% injected dose/g, % ID/g and 0.08 ± 0.01 ID/g, respectively), consistent with in vivo specific binding to the 5-HT2A receptor. Furthermore, specific [18F]RP 62203 binding significantly correlated with the reported in vitro distribution of 5-HT2A receptors, but not with known concentration profiles of dopaminergic D2 or adrenergic α1 receptors. Finally, detectable specific binding was abolished by pretreatment with large doses of ritanserin, a selective 5-HT2A antagonist, which resulted in uniform uptakes across cortical, striatal and cerebellar tissues. Thus, [18F]RP 62203 appears to be a promising selective tool to visualize and quantify 5-HT2A brain receptors in vivo with positron emission tomography

  3. Are Older Adults Prepared to Ensure Food Safety during Extended Power Outages and Other Emergencies?: Findings from a National Survey

    Science.gov (United States)

    Kosa, Katherine M.; Cates, Sheryl C.; Karns, Shawn; Godwin, Sandria L.; Coppings, Richard J.

    2012-01-01

    Natural disasters and other emergencies can cause an increased risk of foodborne illness. We conducted a nationally representative survey to understand consumers' knowledge and use of recommended practices during/after extended power outages and other emergencies. Because older adults are at an increased risk for foodborne illness, this paper…

  4. Olkiluoto 1 and 2 - Plant efficiency improvement and lifetime extension-project (PELE) implemented during outages 2010 and 2011

    International Nuclear Information System (INIS)

    Teollisuuden Voima Oyj (TVO) is a non-listed public company founded in 1969 to produce electricity for its stakeholders. TVO is the operator of the Olkiluoto nuclear power plant. TVO follows the principle of continuous improvement in the operation and maintenance of the Olkiluoto plant units. The PELE project (Plant Efficiency Improvement and Lifetime Extension), mainly completed during the annual outages in 2010 and 2011, and forms one part of the systematic development of Olkiluoto units. TVO maintains a long-term development program that aims at systematically modernizing the plant unit systems and equipment based on the latest technology. According to the program, the Olkiluoto 1 and Olkiluoto 2 plant units are constantly renovated with the intention of keeping them safe and reliable, The aim of the modernization projects is to improve the safety, reliability, and performance of the plant units. PELE project at Olkiluoto 1 was done in 2010 and at Olkiluoto 2 in 2011. The outage length of Olkiluoto 1 was 26 d 12 h 4 min and Olkiluoto 2 outage length was 28 d 23 h 46 min. (Normal service-outage is about 14 days including refueling and refueling-outage length is about seven days. See figure 1) The PELE project consisted of several single projects collected into one for coordinated project management. Some of the main projects were as follows: - Low pressure turbines: rotor, stator vane, casing and turbine instrumentation replacement. - Replacement of Condenser Cooling Water (later called seawater pumps) pumps - Replacement of inner isolation valves on the main steam lines. - Generator and the generator cooling system replacement. - Low voltage switchgear replacement. This project will continue during future outages. PELE was a success. 100 TVO employees and 1500 subcontractor employees participated in the project. The execution of the PELE projects went extremely well during the outages. The replacement of the low pressure turbines and seawater pumps improved the

  5. Improving nuclear utility generation capacity, understanding the sources of forced outage and learning how to prevent them

    International Nuclear Information System (INIS)

    MIT and PECO Energy have completed a detailed examination of the sources of forced outages at the Limerick Generating Station (LGS) Boiling Water Reactor Class IV (BWR IV) site over a five year period and contrasted that information to similar BWR IV utilities in the United States over the same period. Each forced outage was attributed to one system and assigned causal codes of equipment versus human factors and failure attributes such as weak design, poor craftsmanship, and worn parts. It was found that fifty four percent of the lost power at LGS was the result of Balance of Plant failures. Industry wide data identifies fifty nine percent of the lost power as attributed to Balance of Plant failures. Balance of Plant systems are those systems not included in the primary and safety related system category. Considering failure causal factors, forty six percent of the lost power at the utility under study was the result of equipment factors such as weak design or worn parts. Significantly, the study showed a high variance between those systems which caused significant forced outage at the two sister LGS units. This demonstrated the infrequent nature of plant forced outages within a given system. This was supported by the observation that dominant systems attributing to forced outage at LGS were not equally represented in industry data. It is suggested that for individual utilities to dramatically improve unit capability factors with regard to Balance of Plant systems, they must learn from industry wide experiences and develop cooperative means of exchanging lessons learned among similarly designed plants and systems. With the broad knowledge base of system failures, current designs must be frequently assessed and altered until each system poses an acceptable level of risk to generation capacity. (author)

  6. Study on Compression Performance of an Innovate FRP Rubber Isolator%新型FRP橡胶支座受压性能研究

    Institute of Scientific and Technical Information of China (English)

    张华; 彭天波

    2011-01-01

    FRP橡胶支座是用FRP复合材料板替代传统板式橡胶支座中的加劲钢板而制成的.已有的试验和理论分析表明FRP橡胶支座在满足一般板式橡胶支座力学性能要求的同时还具有较好的阻尼耗能能力,因此在减隔震设计中具有较好的应用前景.首先对FRP橡胶支座的概念及特点做了基本介绍,在此基础上利用通用有限元程序MSC.MARC对FRP橡胶支座的进行了有限元分析.为了考虑支座设计参数对FRP复合加劲板应力情况以及支座刚度的影响,对不同设计参数的FRP橡胶支座进行了竖向加载数值模拟,对加劲板中的最大应力和支座刚度进行了影响参数分析,初步提出了各设计参数对FRP橡胶支座受压力学性能的影响规律,为FRP橡胶支座的设计应用提供参考.%Fiber reinforced plastic (FRP) rubber isolator is made by replacing the steel reinforcing elements of multilayer elastomeric isolation bearings by fiber reinforcement. Former experimental and theoretical researches have shown that FRP rubber isolator has equivalent performance in shear deformation capacity and vertical loading capacity, but has superior behavior in damping, so broad application prospects of FRP rubber isolator should be expected. This paper aims to study the effects of influential factors on the compression performance of FRP rubber isolator,including the stress in the reinforcement and the compression modulus of the isolator. The concept of the isolator is introduced first, and then numerical simulation is conducted to study the influence of the factors on the isolator. The influence laws of the factors are proposed, which provides references of the design of FRP rubber isolator.

  7. Automatically produced FRP beams with embedded FOS in complex geometry: process, material compatibility, micromechanical analysis, and performance tests

    Science.gov (United States)

    Gabler, Markus; Tkachenko, Viktoriya; Küppers, Simon; Kuka, Georg G.; Habel, Wolfgang R.; Milwich, Markus; Knippers, Jan

    2012-04-01

    The main goal of the presented work was to evolve a multifunctional beam composed out of fiber reinforced plastics (FRP) and an embedded optical fiber with various fiber Bragg grating sensors (FBG). These beams are developed for the use as structural member for bridges or industrial applications. It is now possible to realize large scale cross sections, the embedding is part of a fully automated process and jumpers can be omitted in order to not negatively influence the laminate. The development includes the smart placement and layout of the optical fibers in the cross section, reliable strain transfer, and finally the coupling of the embedded fibers after production. Micromechanical tests and analysis were carried out to evaluate the performance of the sensor. The work was funded by the German ministry of economics and technology (funding scheme ZIM). Next to the authors of this contribution, Melanie Book with Röchling Engineering Plastics KG (Haren/Germany; Katharina Frey with SAERTEX GmbH & Co. KG (Saerbeck/Germany) were part of the research group.

  8. Outage Key Safety Functions Configuration risk assessment for a three loops Westinghouse PWR

    Energy Technology Data Exchange (ETDEWEB)

    Cid, M.M.; Dies, J., E-mail: javier.Dies@Upc.Edu; Tapia, C., E-mail: carlos.Tapia@Upc.Edu; Diaz, P., E-mail: pedro.diaz.bayona@upc.edu

    2015-09-15

    Highlights: • The paper evaluates the use of PSA on the Outage configuration risk management. • A method is proposed based on Risk Criteria to evaluate the OKSFs’ Configurations. • The methodology allows to identify which of the OKSFs can be analyzed using PSA. • The method has been applied to a Pilot real case. The OKSFs procedure is evaluated. - Abstract: The methodology developed provides guidance on the use of Probabilistic Safety Assessment (PSA) for the risk-informed evaluation of Guides which ensure the compliment of Outage Key Safety Functions (OKSFs) in Nuclear Power Plants. The methodology has been applied to the 3rd and 13th Plant Operational States (POSs) as a pilot experience. These POSs are within the Operating Mode 4 (Hot Shutdown) of a three loops Westinghouse Pressurized Water Reactor. The addressed Guide requires the operability of just one charge pump as boric acid supply source. PSA gives a Core Damage Frequency increase (ΔCDF) of 1.19 × 10{sup −6} year{sup −1} for the unavailability of the charge pump in standby, consequently, the maximum exposure time (time for the Increase of Core Damage Probability of the configuration to reach 1.0E−06) for this situation is T = 53.6 h. Given an average time for the POSs of 40 h, it is concluded that the charge pumps requirement is correct. However, it could be improved with the inclusion of an additional inventory replacement function. This would limit the effect on risk of the charge pump unavailability. Furthermore, the need for the external electrical sources to be available during Mode 4 is ratified. The procedure requires the operability of both supply sources during the POSs. The unavailability of one of supply sources them involves a ΔCDF equal to 1.64 × 10{sup −5} year{sup −1} and a maximum exposure time of T = 3.89 h. This requirement is considered appropriate from the risk-informed regulation point of view.

  9. Overview Shear Strengthening of RC Beams with Externally Bonded FRP Composites

    Science.gov (United States)

    Alzoubi, Feras; Zhengliang, Li

    Shear strengthening is required when an RC beam is found deficient in shear, or when its shear capacity falls below its flexural capacity after flexural strengthening. This study presents a state-of-the-art review of existing research on this topic. The research programs conducted to investigate the shear performance and to evaluate the shear capacity of the strengthened beams are reviewed in this paper by details. The research is a good reference for all engineers and researchers in fields of shear strengthening and repair RC beams in building and bridges.

  10. Risk-informed allowed outage time change for Ulchin units 3 and 4

    International Nuclear Information System (INIS)

    In this report, the risk assessment on the change of allowed outage time (AOT) and the on-line maintenance of major safety systems for Ulchin Units 3 and 4 is performed to identify the possibilities of them. The systems for which the risk assessment is performed are High Pressure Safety Injection System (HPSIS), Low Pressure Safety Injection System (LPSIS), Containment Spray System (CSS), Shutdown Cooling System (SCS), Safety Injection Tank (SIT), Component Cooling Water System (CCWS), Essential Service Water System (ESWS), Essential Chilled Water System (ECWS), and Emergency Diesel Generator (EDG). Major measures for risk assessment are core damage frequency and large early release frequency. Comprehensive evaluation results from PSA aspects are as follows: 1) It is expected that present AOT of 3days for EDG can be extended to 10 days, that of 3days for LPSIS, SCS, CSS to 7 days, and that of 1 hour for SIT to 24 hours. 2) The risk on the AOT change can be optimistically estimated without the consideration for the change of common cause failure probabilities and initiating event frequencies. 3) It is expected that on-line preventive maintenance of LPSIS, CSS, SCS, CCWS, ESWS, ECWS, and EDG can be performed without greatly increasing the risk

  11. Stability and Distributed Power Control in MANETs with Outages and Retransmissions

    CERN Document Server

    Giovanidis, Anastasios

    2009-01-01

    In the current work the effects of hop-by-hop packet loss and retransmissions via ARQ protocols are investigated within a Mobile Ad-hoc NET-work (MANET). Errors occur due to outages and a success probability function is related to each link, which can be controlled by power and rate allocation. We first derive the expression for the network's capacity region, where the success function plays a critical role. Properties of the latter as well as the related maximum goodput function are presented and proved. A Network Utility Maximization problem (NUM) with stability constraints is further formulated which decomposes into (a) the input rate control problem and (b) the scheduling problem. Under certain assumptions problem (b) is relaxed to a weighted sum maximization problem with number of summants equal to the number of nodes. This further allows the formulation of a non-cooperative game where each node decides independently over its transmitting power through a chosen link. Use of supermodular game theory sugge...

  12. The Loss of Spent Fuel Pool Cooling Analysis during Plant Outage for OPR1000

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol Woo; Huh, Jae Young [KEPCO E-C, Daejeon (Korea, Republic of)

    2014-10-15

    Recently, spent fuels stored in the spent fuel pool (SFP) with a loss of cooling during the refueling of plant outage have been required to maintain their integrity especially after the Fukushima disaster. A thermal-hydraulic analysis of the loss of SFP cooling (LOSFPC) during the plant operating state 8 (POS 8) or refueling period is performed to establish the success criteria for the probabilistic safety assessment (PSA). This paper is to investigate the incipient boiling time in the spent fuel region, time to uncover in the SFP and the time of fuel cladding failure for the Hanul Nuclear Power Plant Units 3 and 4 (HUN 3 and 4) which is the typical optimized power reactor 1000 (OPR1000). The results show that the sufficient time for operator action is available for the LOSFPC during the refueling period for the OPR1000. From a loss of SFP cooling analysis for HUN 3 and 4, RELAP5/MOD3.3 shows reasonable thermal-hydraulic behaviors and is acceptable to establish the success criteria of operator action for the PSA.

  13. A study on assessment methodology of surveillance test interval and allowed outage time

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chang Hyun; You, Young Woo; Cho, Jae Seon; Huh, Chang Wook; Kim, Do Hyoung; Kim, Ju Youl; Kim, Yoon Ik; Yang, Hui Chang; Park, Kang Min [Seoul National Univ., Seoul (Korea, Republic of)

    1998-03-15

    The objectives of this study is the development of methodology by which assesses the optimization of Surveillance Test Internal(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korean nuclear power plant safety. In this study, the survey about the assessment methodologies, modelings and results performed by domestic and international researches are performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method. The sensitivity analyses about the failure factors of the components are performed in the bases of the and AOT is quantified. And the reliability assessment methodology about the diesel generator is reviewed and applied to the PSA code. The qualitative assessment for the STI/AOR of RPS/ESFAS assured safety the most important system in the nuclear power plant are performed.

  14. Foreign Objects Found in Steam Generator 'Cold' Header During Scheduled Maintenance Outage

    International Nuclear Information System (INIS)

    During scheduled maintenance outage on the Unit in the course of TV examination of the 'cold header' on Steam Generator 2 (SG-2) to check for cleanliness and for subsequent pressurization, the following foreign material was found: M4x8 mm stainless steel bolt; 15x2 mm piece of plastic clamp; two 10x10 mm pieces of black-colour reinforced hose; Undetermined particulate. On completion of examination all the above objects were removed from the header. No breach of safe operation limits and conditions occurred. The foreign objects fell into SG-2 'cold' header from a maintenance platform during SG-2 repair works; no requirement for maintenance plugs for header was identified to avoid foreign material intrusion. Contractors and plant personnel were allowed to work unsupervised during the maintenance work. Maintenance documentation did not identify the actions required and risk assessment to avoid foreign material intrusion into the primary circuit during activities performed on depressurized components of the reactor installation. (author)

  15. Risk-based evaluation of Allowed Outage Times (AOTs) considering risk of shutdown

    International Nuclear Information System (INIS)

    When safety systems fail during power operation, Technical Specifications (TS) usually limit the repair within Allowed Outage Time (AOT). If the repair cannot be completed within the AOT, or no AOT is allowed, the plant is required to be shut down for the repair. However, if the capability to remove decay heat is degraded, shutting down the plant with the need to operate the affected decay-heat removal systems may impose a substantial risk compared to continued power operation over a usual repair time. Thus, defining a proper AOT in such situations can be considered as a risk-comparison between the repair in frill power state with a temporarily increased level of risk, and the altemative of shutting down the plant for the repair in zero power state with a specific associated risk. The methodology of the risk-comparison approach, with a due consideration of the shutdown risk, has been further developed and applied to the AOT considerations of residual heat removal and standby service water systems of a boiling water reactor (BWR) plant. Based on the completed work, several improvements to the TS requirements for the systems studied can be suggested

  16. Risk-Based Allowed Outage Time and Surveillance Test Interval Extensions for Angra 1

    Directory of Open Access Journals (Sweden)

    Sonia M. Orlando Gibelli

    2012-01-01

    Full Text Available In this work, Probabilistic Safety Assessment (PSA is used to evaluate Allowed Outage Times (AOT and Surveillance Test Intervals (STI extensions for three Angra 1 nuclear power plant safety systems. The interest in such an analysis lies on the fact that PSA comprises a risk-based tool for safety evaluation and has been increasingly applied to support both the regulatory and the operational decision-making processes. Regarding Angra 1, among other applications, PSA is meant to be an additional method that can be used by the utility to justify Technical Specification relaxation to the Brazilian regulatory body. The risk measure used in this work is the Core Damage Frequency, obtained from the Angra 1 Level 1 PSA study. AOT and STI extensions are evaluated for the Safety Injection, Service Water and Auxiliary Feedwater Systems using the SAPHIRE code. In order to compensate for the risk increase caused by the extensions, compensatory measures as (1 test of redundant train prior to entering maintenance and (2 staggered test strategy are proposed. Results have shown that the proposed AOT extensions are acceptable for two of the systems with the implementation of compensatory measures whereas STI extensions are acceptable for all three systems.

  17. Outage and ser performance of spectrum sharing system with TAS/MRC

    KAUST Repository

    Khan, Fahd Ahmed

    2013-06-01

    Capacity of the secondary network degrades due to the interference constraint from the primary network. The secondary network capacity can be enhanced by means of spatial diversity, that can be achieved by adding multiple antennas on the terminals. In this paper, the performance of a multiple-input multiple-output (MIMO) secondary link with transmit antenna selection (TAS) at the transmitter and maximum ratio combining (MRC) at the receiver is analysed. A peak transmit power constraint is considered in addition to the interference power constraint. For a Rayleigh faded channel, closed-form expression for the outage probability of a MIMO cognitive system (MIMO-CS) with TAS/MRC is derived. In addition, closed-form expressions of the moment generating function and the symbol error rate are also obtained. The performance of this system is analyzed for asymptotic regimes and it is shown that TAS/MRC in a MIMO-CS achieves a generalized diversity order of nTnR, where nT and nR are the number of transmit and receive antennas, respectively. Numerical results are also presented to corroborate the derived analytical results. © 2013 IEEE.

  18. Multi-factorial analysis of occupational outage doses dispersion in the French NPPs 1998-2002

    International Nuclear Information System (INIS)

    Since 1992, many improvements have been achieved at EDF in terms of reducing occupational radiological exposures. Many efforts have been done in several areas, but without knowing what are the factors that have most influenced these results. It would therefore be of interest now to know more about that in order to be able to decide where to invest with an optimal efficiency to further improve occupational radiological protection. The results presented here are just examples of what can be done with such a study both in France and at the international level with ISOE 2 data when fulfilled; they may be considered as preliminary results. Consequently, they must be confirmed and validated. Of course, some variables such as zinc injection have not been studied here, as they were not relevant in France. Some others have not been kept such as biological shielding tons installed during the outage, as the information was not available in the French plants. However that study has pointed out the interest of mixing qualitative and quantitative variables, the interest of mixing descriptive statistical analysis with the analysis of correlations between dose dispersion and other variables dispersions as well as there evolution with time

  19. Optimal Power Allocation for Fading Channels in Cognitive Radio Networks: Ergodic Capacity and Outage Capacity

    CERN Document Server

    Kang, Xin; Nallanathan, Arumugam; Garg, Hari Krishna; Zhang, Rui

    2008-01-01

    A cognitive radio network (CRN) is formed by either allowing the secondary users (SUs) in a secondary communication network (SCN) to opportunistically operate in the frequency bands originally allocated to a primary communication network (PCN) or by allowing SCN to coexist with the primary users (PUs) in PCN as long as the interference caused by SCN to each PU is properly regulated. In this paper, we consider the latter case, known as spectrum sharing, and study the optimal power allocation strategies to achieve the ergodic capacity and the outage capacity of the SU fading channel under different types of power constraints and fading channel models. In particular, besides the interference power constraint at PU, the transmit power constraint of SU is also considered. Since the transmit power and the interference power can be limited either by a peak or an average constraint, various combinations of power constraints are studied. It is shown that there is a capacity gain for SU under the average over the peak ...

  20. Study on risk-informed determination method of allowed outage time in fast reactor systems

    International Nuclear Information System (INIS)

    The present report describes a study aiming at proposing a method to determine the allowed outage time (AOT) after detecting a failure in the equipment that stands by during fast reactor power operation by taking into account risk information rationally. In the present study, an improved risk estimation model based on the previous study was constructed so as to consider properly that the repaired component was returned to the standby state again when the repair action completed within the range of AOT. Based on the improved model, core damage probability (CDP) per each detection of the failure is expressed as a function depending on the elapsed time after failure detection. In addition, there are the upper and lower bound values of CDP, and the CDP changes monotonously (i.e., either decreases or increases) between a pair of both the bound values. If a target value of CDP that is not lower than the lower bound can be given, it is possible to determine AOT, where the point-estimation value of CDP becomes lower than or equal to the target value because CDP depends on the elapsed time. Finally, we developed the procedure for determining the AOT from the view point of maintaining the total core damage frequency less than or equal to a prescribed target value. (author)

  1. The Application of Phasor Measurement Units in Transmission Line Outage Detection Using Support Vector Machine

    Directory of Open Access Journals (Sweden)

    A. Y. Abdelaziz

    2013-07-01

    Full Text Available Many protection applications are based upon the Phasor Measurement Units (PMUs technology. Therefore, PMUs have been increasingly widespread throughout the power network, and there are several researches have been made to locate the PMUs for complete system observability. This paper introduces an important application of PMUs in power system protection which is the detection of single line outage. In addition, a detection of the out of service line is achieved depending on the variations of phase angles measured at the system buses where the PMUs are located. Hence, a protection scheme from unexpected overloading in the network that may lead to system collapse can be achieved. Such detections are based upon an artificial intelligence technique which is the support Vector Machine (SVM classification tool. To demonstrate the effectiveness of the proposed approach, the algorithm is tested using offline simulation for both the 14-bus IEEE and the 30-bus IEEE systems. Two different kernels of the SVM are tested to select the more appropriate one (i.e. polynomial and Radial Basis Function (RBF kernels are used.

  2. Intermediate report of MoReMo. Modelling resilience for maintenance and outage

    Energy Technology Data Exchange (ETDEWEB)

    Oedewald, P.; Macchi, L. (VTT Technical Research Centre of Finland (Finland)); Axelsson, C. (Ringhals AB, Vattenfall AB (Sweden)); Eitrheim, M.H.R. (Institute for Energy Technology (Norway))

    2012-02-15

    Resilience Engineering (RE) is a new approach to safety that helps organisations and individuals adapt to unforeseen events and long-term changes. Such an approach is needed by nuclear power plants (NPPs) as they face demanding modification projects, high staff turnover and increased pressures to maintain and improve safety. The goal of the Modelling Resilience for Maintenance and Outage (MoReMO) project is to develop and test models and methods to identify and analyse resilience in safety-critical activities in natural everyday settings. In 2011, we have applied four approaches in different case studies: Organisational Core Task modelling (OCT), Functional Resonance Analysis Method (FRAM), Efficiency Thoroughness Trade-Off (ETTO) analysis, and Work Practice and Culture Characterisation. The project has collected data through observations, interviews and document reviews at two NPPs. Together, the four approaches have provided valuable insights for understanding the rationale behind work practices, their effects on safety, and the support of flexibility and adaptability. In 2012, the MoReMO project will complete the data collection and integrate results on how resilience can be operationalized in practical safety management tools for the companies. (Author)

  3. Optimal PMU placement for maintaining full network observability during single outage of lines

    Directory of Open Access Journals (Sweden)

    Fariborz Haghighatdar fesharaki

    2011-05-01

    Full Text Available Nowadays, the optimal application of phasor measurement units (PMUs in power systems is increasing because of their advantages such as the capability for dynamical state estimation and improvements in the speed of control and protection systems. In this paper, a new method is presented using binary integer linear programming for the optimal placement of PMUs to guarantee full observability of a power system. Moreover, the problem of the optimal placement of these units in the case of a single line outage is investigated. In all of the investigations, the effect of zero-injection buses in the power system was considered. The ability of the proposed method in solving any of these problems was demonstrated by applying to the 14-, 30-, 39-, 57- and 118-bus IEEE standard systems, 42-bus transmission network of Esfahan Regional Electric and also two very large-scale systems with 2383 and 2746 buses. The simulation results verified the effective and appropriate performance of the proposed method in comparison with other methods.

  4. A study on assessment methodology of surveillance test interval and Allowed Outage Time

    Energy Technology Data Exchange (ETDEWEB)

    Che, Moo Seong; Cheong, Chang Hyeon; Ryu, Yeong Woo; Cho, Jae Seon; Heo, Chang Wook; Kim, Do Hyeong; Kim, Joo Yeol; Kim, Yun Ik; Yang, Hei Chang [Seoul National Univ., Seoul (Korea, Republic of)

    1997-07-15

    Objectives of this study is the development of methodology by which assesses the optimization of Surveillance Test Interval(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korean nuclear power plants safety. In the first year of this study, the survey about the assessment methodologies, modeling and results performed by domestic and international researches are performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method. In the second year of this study, the sensitivity analyses about the failure factors of the components are performed in the bases of the assessment methodologies of the first study, the interaction modeling of the STI and AOT is quantified. And the reliability assessment methodology about the diesel generator is reviewed and applied to the PSA code.

  5. A study on maintenance optimization by the automatic planning tool for regular plant outage work in nuclear power plant using the logic programming language 'Prolog'

    International Nuclear Information System (INIS)

    This paper discusses maintenance optimization by the automatic planning tool for regular plant outage work in nuclear power plant using the logic programming language 'Prolog'. As a result of consideration, the following results were obtained. (1) The automatic planning tool for regular plant outage in nuclear power plant was developed. (2) Using this tool, the work plan for BWR primary recirculation system and residual heat removal system was automatically made on the condition of flattening man loading over the plant outage schedule as much as possible. (3) Several points for improving the developed tool were listed. (author)

  6. Exact Outage Probability of Dual-Hop CSI-Assisted AF Relaying Over Nakagami-m Fading Channels

    KAUST Repository

    Xia, Minghua

    2012-10-01

    In this correspondence, considering dual-hop channel state information (CSI)-assisted amplify-and-forward (AF) relaying over Nakagami- m fading channels, the cumulative distribution function (CDF) of the end-to-end signal-to-noise ratio (SNR) is derived. In particular, when the fading shape factors m1 and m2 at consecutive hops take non-integer values, the bivariate H-function and G -function are exploited to obtain an exact analytical expression for the CDF. The obtained CDF is then applied to evaluate the outage performance of the system under study. The analytical results of outage probability coincide exactly with Monte-Carlo simulation results and outperform the previously reported upper bounds in the low and medium SNR regions.

  7. Experimental Investigation on Bridge Structures Reinforced by FRP Grids Underwater%纤维网格加固桥梁水下结构试验研究

    Institute of Scientific and Technical Information of China (English)

    魏洋; 吴刚; 纪军; 张敏

    2014-01-01

    FRP grids have an excellent application prospect in the field of civil engineering due to its light weight, corrosion resistance and easy formation. Based on the conception of construction underwater without water drainage, the construction technology of FRP grids reinforced bridge structures underwater was presented. Five groups consisting of fifteen cylindrical concrete specimens were prepared to investigate the efficiency of the FRP grids reinforced underwater structures. The main parameters were the type of bonding material ( underwater non-dispersion mortar or underwater epoxy resin ) and casting conditions of bonding material ( land or underwater ) . Test results show that the load-carrying and deformation capacity of FRP grids reinforced specimens were enhanced by confining core concrete. Whether the bonding material was underwater non-dispersion mortar or underwater epoxy resin, the positive effects of FRP grids reinforced underwater structures could be achieved by the manner of no water drainage. When the bonding material is underwater non-dispersion mortar, the load-displacement curves of the specimens show a relatively smooth descending trend; when the bonding material is underwater epoxy resin, the load-displacement curves show a progressive and stepped descending trend. However, there is no significant difference in the overall deformability between them.%FRP网格以其轻质、耐腐蚀、易成型,在土木工程领域具有很好的应用前景。基于水下无排水施工思想,提出了FRP网格加固桥梁水下结构的施工工艺,共制作了5组15个混凝土圆柱试件,研究FRP网格加固水下结构的技术效果,研究参数包括黏结材料类型(水下不分散砂浆、水下环氧树脂)、黏结材料浇筑条件(陆上浇筑、水下浇筑)。试验结果表明,FRP网格通过对加固结构核心混凝土的约束实现其承载力和变形能力的提高,黏结材料无论是水下不分散砂浆还是

  8. Control of the risk of exposure to alpha-emitting radionuclides during an outage in a nuclear power plant

    International Nuclear Information System (INIS)

    Control of the risk of external exposure of EDF PWR plant maintenance workers by alpha-emitting radionuclides is based on identification and quantification of the contamination of the systems. Appropriate arrangements are made to ensure protection on the basis of the prior analysis of the risk. In 2001, an experiment carried out at Cattenom Power Plant during a unit outage in the presence of a leaking fuel, based on measurement of alpha-emitting radionuclides, made it possible to determine a realistic factor for the resuspension of particles. On the basis of the experimental results, a resuspension factor of 10-6 m-1 for operational radiological protection was adopted. In the case of this unit outage, an appropriate surveillance system using this resuspension factor for workers was set in place in collaboration with the occupational medicine and radiological protection department. It was based on prior estimation of the level of alpha contamination, and confirmed by swipe measurements, atmospheric surveillance by monitors, and collective analysis by nose blow samples from workers selected on the basis of their workstations, as well as supplementary individual measurements (monitoring of faeces). This surveillance made it possible to validate an appropriate work area monitoring system, as well as the means of individual and collective protection adopted, and to establish that there was no contamination of staff by actinides during the unit outage. (authors)

  9. Spectrum Sharing in an ISM Band: Outage Performance of a Hybrid DS/FH Spread Spectrum System with Beamforming

    Directory of Open Access Journals (Sweden)

    Hanyu Li

    2009-01-01

    Full Text Available This paper investigates spectrum sharing issues in the unlicensed industrial, scientific, and medical (ISM bands. It presents a radio frequency measurement setup and measurement results in 2.4 GHz. It then develops an analytical model to characterize the coexistence interference in the ISM bands, based on radio frequency measurement results in the 2.4 GHz. Outage performance using the interference model is examined for a hybrid direct-sequence frequency-hopping spread spectrum system. The utilization of beamforming techniques in the system is also investigated, and a simplified beamforming model is proposed to analyze the system performance using beamforming. Numerical results show that beamforming significantly improves the system outage performance. The work presented in this paper provides a quantitative evaluation of signal outages in a spectrum sharing environment. It can be used as a tool in the development process for future dynamic spectrum access models as well as engineering designs for applications in unlicensed bands.

  10. Outage Performance Analysis of Relay Selection Schemes in Wireless Energy Harvesting Cooperative Networks over Non-Identical Rayleigh Fading Channels.

    Science.gov (United States)

    Do, Nhu Tri; Bao, Vo Nguyen Quoc; An, Beongku

    2016-01-01

    In this paper, we study relay selection in decode-and-forward wireless energy harvesting cooperative networks. In contrast to conventional cooperative networks, the relays harvest energy from the source's radio-frequency radiation and then use that energy to forward the source information. Considering power splitting receiver architecture used at relays to harvest energy, we are concerned with the performance of two popular relay selection schemes, namely, partial relay selection (PRS) scheme and optimal relay selection (ORS) scheme. In particular, we analyze the system performance in terms of outage probability (OP) over independent and non-identical (i.n.i.d.) Rayleigh fading channels. We derive the closed-form approximations for the system outage probabilities of both schemes and validate the analysis by the Monte-Carlo simulation. The numerical results provide comprehensive performance comparison between the PRS and ORS schemes and reveal the effect of wireless energy harvesting on the outage performances of both schemes. Additionally, we also show the advantages and drawbacks of the wireless energy harvesting cooperative networks and compare to the conventional cooperative networks. PMID:26927119

  11. Outage Analysis of Train-to-Train Communication Model over Nakagami-m Channel in High-Speed Railway

    Directory of Open Access Journals (Sweden)

    Pengyu Liu

    2013-01-01

    Full Text Available This paper analyzes the end-to-end outage performance of high-speed-railway train-to-train communication model in high-speed railway over independent identical and nonidentical Nakagami-m channels. The train-to-train communication is inter-train communication without an aid of infrastructure (for base station. Source train uses trains on other rail tracks as relays to transmit signals to destination train on the same track. The mechanism of such communication among trains can be divided into three cases based on occurrence of possible-occurrence relay trains. We first present a new closed form for the sum of squared independent Nakagami-m variates and then derive an expression for the outage probability of the identical and non-identical Nakagami-m channels in three cases. In particular, the problem is improved by the proposed formulation that statistic for sum of squared Nakagami-m variates with identical m tends to be infinite. Numerical analysis indicates that the derived analytic results are reasonable and the outage performance is better over Nakagami-m channel in high-speed railway scenarios.

  12. Survey of PWR plant personnel on shutdown safety practices and risk management needs. EPRI Outage Risk Assessment and Management (ORAM) program. Final report, March 1992

    International Nuclear Information System (INIS)

    Nuclear power plant operating experience has shown that PWRs are susceptible to a variety of events during shutdown conditions. At the request of its member utilities, EPRI initiated a program to develop an integrated technical assistance package for evaluating and managing risk during shutdown operation. This program is called the Outage Risk Assessment and Management (ORAM) Program. One of the tasks of the program was to survey EPRI member utilities to gain insights into existing outage management practices. In June of 1991 a questionnaire was developed and sent to the EPRI member utilities that operate pressurized water reactors to solicit information concerning current outage management practices. The questionnaire covered four main topics 1) general outage management; 2) refueling; 3) risk quantification and 4) operating staff insights. The information obtained from the survey and insights acquired from site interviews were used as input in making generic probabilistic assessments and in developing risk management guidelines. The report contains a summary of the survey responses. (author)

  13. Refuerzo a cortante de vigas de hormigón armado, mediante laminados de polímeros reforzados con fibras (FRP)

    OpenAIRE

    Pujol, Mireia; Bairán García, Jesús Miguel; Oller Ibars, Eva; Marí Bernat, Antonio Ricardo

    2011-01-01

    En la actualidad, la aplicación de laminados de polímeros reforzados con fibras (FRP) en el campo de la reparación y del refuerzo de estructuras de hormigón resulta cada vez más frecuente. Si bien los mecanismos de rotura están bien definidos a flexión, no sucede lo mismo en el caso del cortante. De acuerdo con la base de datos experimentales recopilada por los autores, existe una gran dispersión entre los resultados obtenidos experimentalmente y los obtenidos analíticamente siguiendo reco...

  14. Cálculo en agotamiento de secciones de fábrica reforzadas a flexión con láminas de FRP

    Directory of Open Access Journals (Sweden)

    Martínez, S.

    2015-12-01

    Full Text Available Masonry structures can hardly resist tensile loads. For this reason these structures are vulnerable to accidental actions, such as earthquakes, or when they suffer damage that change their geometry conditions, for instead, due to differential soil settlements. This paper presents an ultimate limit state method for checking FRP-strengthened unreinforced masonry sections. The method is similar to the one used for reinforced concrete members, but it is adapted to masonry and FRP laminates particularities. In this proposal a bilinear strength-strain relationship is used and the FRP design strain is limited to take into account different aspects which cause the plate can’t reach its ultimate strength. In particular, it is proposed a “bond reduction factor”, derived from a large bending test database.Las estructuras de fábrica apenas tienen capacidad para resistir tracciones lo que las hace vulnerables ante acciones desestabilizantes de tipo accidental, como terremotos, o cuando sufren daños que alteran su geometría, por ejemplo, por asientos diferenciales. En este trabajo se presenta un método para la comprobación en agotamiento de secciones de fábrica reforzadas a flexión con láminas de FRP. Está basado en el procedimiento de cálculo de la capacidad resistente de secciones de hormigón pero adaptado a las particularidades y condicionantes de las fábricas reforzadas. En esta propuesta se utiliza un diagrama de cálculo tensión deformación de la fábrica de tipo bilineal y se limita la deformación de cálculo del refuerzo teniendo en consideración ciertos aspectos que provocan que no pueda desarrollar toda su resistencia. En concreto, se propone un «coeficiente reductor por adherencia» que se determina a partir de una amplia base de datos con ensayos de flexión.

  15. FRP加固混凝土柱的位移延性系数研究%DISPLACEMENT DUCTILITY COEFFICIENT OF FRP-STRENGTHENED RC COLUMNS

    Institute of Scientific and Technical Information of China (English)

    李刚; 傅仕磊; 林巍

    2011-01-01

    简要概括了FRP抗震加固混凝土柱的位移延性系数的相关研究成果,包括其影响因素和计算公式,尤其是塑性铰区高度,并提出进一步的研究趋向和思路.%This paper presents a brief review on displacement ductility coefficient of FRP -strengthened RC columns, including influence factors and useful formulas, particularly in plastic hinge length. Also useful conclusions for further investigations are proposed.

  16. Down-select ion specific media (ISM) utilization in upset and outage conditions

    International Nuclear Information System (INIS)

    This paper presents a process that has been used to help nuclear power plant (NPP) clients resolve some of their more challenging waste water processing issues. These treatment issues may become even more evident during outage conditions, due (in part) to associated decontamination activities that may cause off-normal chemical conditions, which may subsequently change both the peak levels of activities for radionuclides introduced into the collected waste water and also the chemical forms in which they may exist (e.g., formation of colloids or soluble chelates). In one NPP waste processing example, a large proportion of soluble Co-58, which is normally present as a soluble cationic species or an uncharged colloidal solid, was found to behave like an anion; formation of an anionic chelation complex was implicated, possibly due to suspect EDTA, or similar additive, in a proprietary decontamination soap formulation. Antimony 125 (Sb125), normally present as a weakly anionic (Sb(OH)6-) or even neutral (Sb(OH)30) species, was being displaced from previously-loaded media by other, more strongly bound species, causing an unacceptable peak activity in water intended for discharge. A quick resolution of the existing waste processing limitations was required, due to limited waste water holding capacity. Samples of the authentic NPP waste water containing the recalcitrant radionuclides were sent to our licensed off-site laboratory (MCLinc), where small-scale batch-equilibrium testing was used to down-select, from a large number (36) of candidate media (both commercially available and developed internally), those that were relatively effective and economical for use in achieving the required discharge criteria. Batch equilibrium testing is very efficient for use in screening the relative effectiveness of contaminant removal by candidate media in a select waste water composition, and can also provide an estimate of the ultimate contaminant loading capacities on the candidate

  17. Conversion of NfsA, the Major Escherichia coli Nitroreductase, to a Flavin Reductase with an Activity Similar to That of Frp, a Flavin Reductase in Vibrio harveyi, by a Single Amino Acid Substitution

    Science.gov (United States)

    Zenno, Shuhei; Kobori, Toshiro; Tanokura, Masaru; Saigo, Kaoru

    1998-01-01

    NfsA is the major oxygen-insensitive nitroreductase of Escherichia coli, similar in amino acid sequence to Frp, a flavin reductase of Vibrio harveyi. Here, we show that a single amino acid substitution at position 99, which may destroy three hydrogen bonds in the putative active center, transforms NfsA from a nitroreductase into a flavin reductase that is as active as the authentic Frp and a tartrazine reductase that is 30-fold more active than wild-type NfsA. PMID:9440535

  18. 混杂FRP复合材料性能及其加固腐蚀RC梁弯曲性能研究%Research on Material Properties of Hybrid FRP Composites and Flexural Performance for Strengthening Corroded RC Beams

    Institute of Scientific and Technical Information of China (English)

    邵运达; 李建辉

    2012-01-01

    在混杂FRP(Fiber Reinforced Polymer)复合材料单轴拉伸性能研究的基础上,通过对四根腐蚀混凝土梁的弯曲试验,研究了碳/芳纶/玻璃三种纤维层间混杂布对腐蚀混凝土梁弯曲性能的影响.结果表明:(1)混杂FRP复合材料均表现出良好的混杂效应,但碳/芳纶/玻璃三种纤维的混杂效应最优,其混杂效应系数达到0.453.(2)碳/芳纶/玻璃层间混杂纤维布加固腐蚀梁的开裂、屈服、峰值、极限荷载相比未加固腐蚀梁分别提高了14%、60%、98%和91%,而位移延性系数仅降低11%,表明混杂纤维布可显著改善腐蚀混凝土梁的弯曲性能,这将为混杂FRP复合材料加固腐蚀混凝土结构性能评估与加固设计提供参考.%Based on the uniaxial tensile properties of hybrid FRP composites, The effects of CFRP (Carbon FRP)/AFRP (Aramid FRP)/GFRP (Glass FRP) laminated hybrid fiber sheets on the flexural performance of corroded RC beam was investigated by ihe flexural experiments of four corroded RC beams, results show that (1) the hybrid FRP composites occurs good hybrid effect, and hybrid effect of CFRP/AFRP/GFRP laminated hybrid composites is optimum, its hybrid effect coefficients is 0.453. (2) compared with the un - strengthened corroded RC beam, the cracking load, yield load, maximum load and ultimate load of corroded RC beam strengthened with CFRP/AFRP/GFRP hybrid sheets is respectively increased by 14% , 60% , 98% and 91% , but the displacement ductility index is only decreased by 11 % , which indicates that the hybrid FRP sheets can improve significantly the flexural performance of corroded RC beam. The reference of the evaluating and design of corroded RC structures strengthened with hybrid FRP composites is provided.

  19. Experimental study on durability of FRP entirely-wrapped concrete cylinders and FRP strip-wrapped concrete cylinders under wet-dry cycles in salt solution%干湿环境下FRP全裹与条带间隔加固混凝土圆柱耐久性试验研究

    Institute of Scientific and Technical Information of China (English)

    李趁趁; 高丹盈; 赵军

    2009-01-01

    通过碳纤维布(CFRP)和玻璃纤维布(GFRP)全裹黏贴加固与条带间隔黏贴加固混凝土圆柱在盐溶液干湿循环作用下的轴心受压试验,对比分析环境作用、纤维布类型、纤维布黏贴方式对混凝土圆柱轴压性能的影响.结果表明,经过盐溶液干湿循环作用之后,FRP加固混凝土圆柱的强度和延性有所降低,CFRP加固柱比GFRP加固柱耐干湿循环性能好.如果从提高强度、抗震能力、耐久性方面考虑,全裹黏贴方式优于条带间隔黏贴方式,在盐溶液干湿循环环境下,可以考虑采用FRP全裹黏贴加固混凝土结构,在提高混凝土结构受力性能的同时,以全裹黏贴加固方式来延缓外界环境对混凝土的侵蚀,延长混凝土结构的寿命.但从经济方面考虑,FRP约束对圆柱强度的提高程度并不与FRP用量成正比,条带黏贴方式比全裹黏贴方式更经济.建立了考虑盐溶液干湿循环影响的FRP条带柱与全裹柱的承载力计算模型.%The effects of the environment, FRP type and bonding manner on the durability of concrete cylinders were studied by comparing the compressive performance of specimens confined with carbon fiber reinforced polymer (CFRP), glass fiber reinforced polymer (GFRP) wraps and without any wrap, under wet-dry cycles in salt solution. The experimental resuhs show that strength and ductility of FRP strengthened concrete cylinders decrease after wet-dry cycles in salt solution. Concrete cylinders confined with CFRP are more resistant to wet-dry cycles in salt solution than those cylinders confined with GFRP. In terms of improving strength, earthquake-resistant capacity and durability of concrete structure, the entirely-wrapped specimens perform better than those strip-wrapped ones. The entire-wrap can be adopted when using FRP to strengthen concrete structures under wet-dry cycles in salt solution, in order to improve the mechanical performance of the concrete structure, defer

  20. FRP约束混凝土压弯构件力学性能的理论分析%THEORETICAL ANALYSIS OF MECHANICAL PROPERTIES OF FRP-CONFINED CONCRETE BEAM-COLUMNS

    Institute of Scientific and Technical Information of China (English)

    陶忠; 于清

    2001-01-01

    Based on the determination of stress-model of FRP-confined concrete,a kind of simplified integral method is applied to calculate the complete curve of load-deformation of FRP-confined beam-columns.The influence of several parameters,such as the strength of FRP composite,concrete,the FRP ratio as well as slenderness ratio on the behavior and bearing capacity of the beam-columns are analyzed.%利用FRP约束混凝土的应力-应变关系模型,采用数值方法,对FRP约束混凝土压弯构件的荷载-变形关系进行了全过程分析,据此考察了FRP极限强度、含FRP率和长细比等参数对该类构件力学性能及承载力的影响,可供有关工程实践参考。

  1. FUNDAMENTAL MECHANICAL MODEL AND ANALYSIS OF SINGLE LAYER FRP WOVEN WEB STRUCTURES%单层FRP编织网结构的基本力学模型与分析

    Institute of Scientific and Technical Information of China (English)

    齐玉军; 冯鹏; 叶列平

    2012-01-01

    FRP大跨编织网结构是一种新型大跨空间结构体系,它由FRP板条按一定规律编织并通过平面外整体张拉构成,具有很好的建筑效果。此结构体系为柔性构件构成的空间整体张拉结构,有4个关键受力状态。该文研究圆形环梁、板条中心对称分布的典型的单层FRP编织网结构,提出了编织网结构力学分析的基本假设和通用力学分析模型,对单层网面进行了平面外整体张拉、全跨荷载工况和半跨荷载工况的理论分析,推导了相应的计算公式,并进行了编织网结构的计算。通过研究建立的FRP编织网结构的基本力学方程,可分析计算单层编织网的各个受力状态,为FRP编织网结构的设计计算提供了理论工具。还进行了参数分析,得到了各参数对结构在使用过程中刚度的影响规律,为FRP编织网结构的初步设计提供了参考。%The fiber-reinforced polymer(FRP) woven web structure(WWS) is an innovative large-span spatial structure composed of FRP strips.The FRP strips are crossed each other and woven to form a flexible web plane,and then the web is stressed integrally in an outer plane.The WWS is a tensegrity spatial structure system made of flexible members of several mechanical statues.The basic assumptions,the fundamental mechanical model,and the equations of the simple FRP WWS of ring beams and central symmetry FRP strips are studied.The equations are drawn.Based on the equations,three load cases of FRP WWS including integrally pre-stressed in an outer plane,the whole span load and half span load are analyzed in theoretical method.The numerical calculations of a simplified FRP WWS are conducted.The fundamental mechanical model of FRP WWS is established,and the theoretical approach for analyzing FRP WWS is concluded.Those provide the theoretical method for calculating of FRP WWS.Through the parameter analysis,the influence principals of parameters on stiffness of structure in

  2. Subsurface defect detection in first layer of pavement structure and reinforced civil engineering structure by FRP bonding using active infrared thermography

    Science.gov (United States)

    Dumoulin, Jean; Ibos, Laurent

    2010-05-01

    In many countries road network ages while road traffic and maintenance costs increase. Nowadays, thousand and thousand kilometers of roads are each year submitted to surface distress survey. They generally lean on pavement surface imaging measurement techniques, mainly in the visible spectrum, coupled with visual inspection or image processing detection of emergent distresses. Nevertheless, optimisation of maintenance works and costs requires an early detection of defects within the pavement structure when they still are hidden from surface. Accordingly, alternative measurement techniques for pavement monitoring are currently under investigation (seismic methods, step frequency radar). On the other hand, strengthening or retrofitting of reinforced concrete structures by externally bonded Fiber Reinforced Polymer (FRP) systems is now a commonly accepted and widespread technique. However, the use of bonding techniques always implies following rigorous installing procedures. To ensure the durability and long-term performance of the FRP reinforcements, conformance checking through an in situ auscultation of the bonded FRP systems is then highly suitable. The quality-control program should involve a set of adequate inspections and tests. Visual inspection and acoustic sounding (hammer tap) are commonly used to detect delaminations (disbonds) but are unable to provide sufficient information about the depth (in case of multilayered composite) and width of debonded areas. Consequently, rapid and efficient inspection methods are also required. Among the non destructive methods under study, active infrared thermography was investigated both for pavement and civil engineering structures through experiments in laboratory and numerical simulations, because of its ability to be also used on field. Pulse Thermography (PT), Pulse Phase Thermography (PPT) and Principal Component Thermography (PCT) approaches have been tested onto pavement samples and CFRP bonding on concrete

  3. Exact closed form expressions for outage probability of GSC receivers over Rayleigh fading channel subject to self-interference

    KAUST Repository

    Nam, Sungsik

    2010-11-01

    Previous work on performance analyses of generalized selection combining (GSC) RAKE receivers based on the signal to noise ratio focused on the development of methodologies to derive exact closed-form expressions for various performance measures. However, some open problems related to the performance evaluation of GSC RAKE receivers still remain to be solved such that an assessment of the impact of self-interference on the performance of GSC RAKE receivers. To have a full and exact understanding of the performance of GSC RAKE receivers, the outage probability of GSC RAKE receivers needs to be analyzed as closed-form expressions. The major difficulty in this problem is to derive some joint statistics of ordered exponential variates. With this motivation in mind, we capitalize in this paper on some new order statistics results to derive exact closed-form expressions for outage probability of GSC RAKE receivers subject to self-interference over independent and identically distributed Rayleigh fading channels. © 2010 IEEE.

  4. Cooperative AF Relaying in Spectrum-Sharing Systems: Outage Probability Analysis under Co-Channel Interferences and Relay Selection

    KAUST Repository

    Xia, Minghua

    2012-11-01

    For cooperative amplify-and-forward (AF) relaying in spectrum-sharing wireless systems, secondary users share spectrum resources originally licensed to primary users to communicate with each other and, thus, the transmit power of secondary transmitters is strictly limited by the tolerable interference powers at primary receivers. Furthermore, the received signals at a relay and at a secondary receiver are inevitably interfered by the signals from primary transmitters. These co-channel interferences (CCIs) from concurrent primary transmission can significantly degrade the performance of secondary transmission. This paper studies the effect of CCIs on outage probability of the secondary link in a spectrum-sharing environment. In particular, in order to compensate the performance loss due to CCIs, the transmit powers of a secondary transmitter and its relaying node are respectively optimized with respect to both the tolerable interference powers at the primary receivers and the CCIs from the primary transmitters. Moreover, when multiple relays are available, the technique of opportunistic relay selection is exploited to further improve system performance with low implementation complexity. By analyzing lower and upper bounds on the outage probability of the secondary system, this study reveals that it is the tolerable interference powers at primary receivers that dominate the system performance, rather than the CCIs from primary transmitters. System designers will benefit from this result in planning and designing next-generation broadband spectrum-sharing systems.

  5. Survey of BWR plant personnel on shutdown safety practices and risk management needs. EPRI Outage Risk Assessment and Management (ORAM) program. Final report, March 1992

    International Nuclear Information System (INIS)

    In response to increasing attention to potential risks during shutdown conditions, nuclear utilities are explicitly addressing safety in their outage planning and management. As part of an integrated package to assist utilities, a survey of BWR utilities was conducted. Detailed interviews with three BWR utilities were supplemented by insights from NRC and BWR Owners Group surveys. The primary objective was to acquire information for use in developing shutdown risk management guidance. Summaries of the interviews and other surveys resulted in thirteen detailed conclusions related to 1) current levels of safety reviews that have a bearing on shutdown operations, 2) the current process for outage planning and management, 3) outage management policies and guidelines that are in use, 4) perceived problems and challenges, and 5) recommendations for future risk management guidance. (author)

  6. Road navigation using multiple dissimilar environmental features to bridge GNSS outages

    OpenAIRE

    Walter, D; Groves, P. D.; Mason, B.; Harrison, J.(School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom); Woodward, J.; Wright, P

    2015-01-01

    Many navigation techniques have now become so reliant on GNSS that there is no back-up when there is limited or no signal reception. If there is interference, deliberate jamming or spoofing, and/or blockage and reflection of the signals by buildings, navigation could be lost or become misleading. Other navigation techniques harness different technologies such as Wi-Fi, eLoran and inertial navigation. However, each of these techniques has its own limitations, such as coverage, degradation in u...

  7. APPLICATION OF QUALITY FUNCTION DEPLOYMENT METHOD AND FUZZY LOGIC FOR IMPROVING THE DESIGN CHARACTERISTICS IN FRP COOLING TOWER-CASE STUDY

    Directory of Open Access Journals (Sweden)

    G.MOHAN KUMAR

    2012-07-01

    Full Text Available Quality Function Deployment is a continuous improvement technique applied in the design of an FRP cooling tower.QFD helps to develop customer oriented, higher quality products. In order to improve the quality characteristics of this product and to satisfy the customers, the technique such as QFD followed by fuzzy logic technique approach is done. Though, the QFD method has some draw backs, it is one of the most important methods to interpret customer needs for specific quality development. To overcome this drawback, fuzzy linguistics approach is proposed in this paper. This paper shows how QFD approach can be combined with fuzzy logic to resolve some of its drawback. Finally, these two approaches have been compared to know whichapplies the best for this case study.

  8. Projecto de reforço à flexão com fibras FRP baseado nas recomendações do ACI 440

    OpenAIRE

    Fortes, Adriano; Padaratz, Ivo J.; Barros, Joaquim A. O.

    2002-01-01

    Desde o final da década de 90, algumas empresas iniciaram a importação de mantas e laminados de polímero reforçado com fibras (Fiber Reinforced Polymer – FRP), para serem utilizados como reforço em peças de concreto armado. A técnica consiste na colagem do material sobre a superfície do concreto, utilizando-se adesivo epóxi. A elevada resistência à tração e à fadiga, a imunidade à corrosão eletroquímica, o baixo peso especifico e a facilidade de aplicação, são algumas das carac...

  9. Estudio de la adherencia entre armaduras de materiales compuestos de matriz polimérica (FRP) y hormigón

    OpenAIRE

    Baena Muñoz, Marta; Torres Llinàs, Lluís; Turon Travesa, Albert; Barris Peña, Cristina

    2008-01-01

    En este artículo se presentan los resultados del estudio del comportamiento adherente de barras de materiales compuestos de matriz polímero (FRP), con fibras de vidrio (GFRP) y con fibras de carbono (CFRP), como armadura de hormigón. Se realizan un total de 91 ensayos según las normas ACI 440.3R-04 y CSA S806-02. Los parámetros considerados en los ensayos son la resistencia del hormigón,e l acabado superficial,e l tipo de fibra y el diámetro de la barra. Los resultados dan una estimación de l...

  10. Open fibre reinforced plastic (FRP) flat plate collector (FPC) and spray network systems for augmenting the evaporation rate of tannery effluent (soak liquor)

    International Nuclear Information System (INIS)

    Presently, tanneries in Tamilnadu, India are required to segregate the effluent of soaking and pickling sections from other wastewater streams and send it to shallow solar pans for evaporation to avoid land pollution. A large area of solar pans is required for evaporating the water in the effluent at salt concentration in the range of 4-5%. An experimental study has been made by using fibre reinforced plastic flat plate collector (FRP-FPC) and spray system in a pilot plant with a capacity to handle 5000 l per day, which increases the evaporation rate. After increasing the salt concentration level to near saturation limit, the concentrated liquid was sent to conventional solar pans for its continued evaporation and recovery of salt. In this improved system, the rate of evaporation was found to be 30-40% more than that in the conventional solar pans. The performance is compared with the theoretically simulated performance. (author)

  11. Operational readiness verification, phase 1: A study on safety during outage and restart of nuclear power plants

    International Nuclear Information System (INIS)

    This report contains the findings from the first phase of a study on safety during outage and restart of nuclear power plants. Operational Readiness Verification (ORV) - in Swedish called Driftklarhetsverifiering (DKV) - refers to the test and verification activities that are necessary to ensure that plant systems are able to provide their required functions when needed - more concretely that all plant systems are in their correct functional state when the plant is restarted after an outage period. The concrete background for this work is that nine ORV related incidents were reported in Sweden between July 1995 and October 1998. The work reported here comprised a literature survey of research relevant for ORV issues, and an assessment of the present situation at Swedish NPPs with respect to ORV. The literature survey was primarily aimed at research related to NPPs, but also looked at domains where similar problems have occurred, such as maintenance in commercial aviation. The survey looked specifically for organisational and MTO aspects relevant to the present situation in Swedish NPPs. One finding was that ORV should be seen as an integral part of maintenance, rather than as a separate activity. Another, that there is a characteristic distribution of error modes for maintenance and ORV, with many sequence errors and omissions, rather than a set of unique error modes. An international study further showed that there are important differences in how procedures are used, and in the balance between decentralisation and centralisation. Several studies also suggested that ORV could usefully be described as a barrier system in relation to the flow of work, for instance using the following five stages: (1) preventive actions during maintenance/outage, (2) post-test after completion of work, (3) pre-test before start-up, (4) the start-up sequence itself, and (5) preventive actions during power operation - possibly including automatic safety systems. In the field survey

  12. Operational readiness verification, phase 1: A study on safety during outage and restart of nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Hollnagel, E. [Linkoeping Univ. (Sweden). Dept. of Computer and Information Science; Gauthereau, V. [Linkoeping Univ. (Sweden). Dept. of Industrial Engineering

    2001-06-01

    This report contains the findings from the first phase of a study on safety during outage and restart of nuclear power plants. Operational Readiness Verification (ORV) - in Swedish called Driftklarhetsverifiering (DKV) - refers to the test and verification activities that are necessary to ensure that plant systems are able to provide their required functions when needed - more concretely that all plant systems are in their correct functional state when the plant is restarted after an outage period. The concrete background for this work is that nine ORV related incidents were reported in Sweden between July 1995 and October 1998. The work reported here comprised a literature survey of research relevant for ORV issues, and an assessment of the present situation at Swedish NPPs with respect to ORV. The literature survey was primarily aimed at research related to NPPs, but also looked at domains where similar problems have occurred, such as maintenance in commercial aviation. The survey looked specifically for organisational and MTO aspects relevant to the present situation in Swedish NPPs. One finding was that ORV should be seen as an integral part of maintenance, rather than as a separate activity. Another, that there is a characteristic distribution of error modes for maintenance and ORV, with many sequence errors and omissions, rather than a set of unique error modes. An international study further showed that there are important differences in how procedures are used, and in the balance between decentralisation and centralisation. Several studies also suggested that ORV could usefully be described as a barrier system in relation to the flow of work, for instance using the following five stages: (1) preventive actions during maintenance/outage, (2) post-test after completion of work, (3) pre-test before start-up, (4) the start-up sequence itself, and (5) preventive actions during power operation - possibly including automatic safety systems. In the field survey

  13. Guidance Document - Provision of Outage Reserve Capacity for Molybdenum-99 Irradiation Services: Methodology and Economic Analysis

    International Nuclear Information System (INIS)

    In June 2011, the OECD Nuclear Energy Agency's (NEA) High-level Group on the Security of Supply of Medical Radioisotopes (HLG-MR) released its policy approach for ensuring a long-term secure supply of molybdenum-99 (99Mo) and its decay product technetium-99m ('99mTc). This policy approach was developed after two years of extensive examination and analysis of the challenges facing the supply chain, and the provision of a reliable, secure supply of these important medical isotopes. The full policy approach can be found in the OECD/NEA report, The Supply of Medical Radioisotopes: The Path to Reliability (NEA, 2011). One of the key principles in the policy approach relates to the provision of outage reserve capacity (ORC) in the 99Mo/'99mTc supply chain, as defined on page 7: 'Principle 2: Reserve capacity should be sourced and paid for by the supply chain. A common approach should be used to determine the amount of reserve capacity required'. This Principle follows the findings of the OECD/NEA report, The Supply of Medical Radioisotopes: An Economic Study of the Molybdenum-99 Supply Chain (NEA, 2010), which clearly demonstrated the need for excess 99Mo production capacity, relative to demand, as some reactors may have to be shutdown unexpectedly or for extended periods. The Study also demonstrated that the pricing structure from reactors for 99Mo irradiation services prior to the 2009-10 supply shortage was not economically sustainable, including the pricing of ORC, with the cost being subsidised by host nations. These nations have indicated a move away from subsidising production, which often benefits foreign nations or foreign companies, and therefore pricing for irradiation services must recover the full cost of production to ensure economic sustainability and a long-term secure supply. Appropriate pricing would also encourage more efficient use of the product, reducing inefficient use of 99Mo/'99mTc would reduce excess production and the associated radioactive

  14. Reactor building

    International Nuclear Information System (INIS)

    The whole reactor building is accommodated in a shaft and is sealed level with the earth's surface by a building ceiling, which provides protection against penetration due to external effects. The building ceiling is supported on walls of the reactor building, which line the shaft and transfer the vertical components of forces to the foundations. The thickness of the walls is designed to withstand horizontal pressure waves in the floor. The building ceiling has an opening above the reactor, which must be closed by cover plates. Operating equipment for the reactor can be situated above the building ceiling. (orig./HP)

  15. Building America

    Energy Technology Data Exchange (ETDEWEB)

    Brad Oberg

    2010-12-31

    IBACOS researched the constructability and viability issues of using high performance windows as one component of a larger approach to building houses that achieve the Building America 70% energy savings target.

  16. Complementary system for monitoring and control of neutron flux during a fuel outage and during reactor start up stage

    International Nuclear Information System (INIS)

    The present work is an example for that, how with modern technical instruments is possible to compensate disadvantage and to increase technical resources of the old systems, without a change of given system totally with new one. The system detail design and implementation was possible mostly, due to the international conferences and courses organised by IAEA and technical information provided by the agency. The designed system plays a role of complementary system to the in-situ operational systems for monitoring and control of the reactor core neutron flux, allowing its measurement and control during a fuel outage and during reactor start up stage. Additionally, the system recalculates the reactivity in beta units and according to its value the reactor criticality fixed up reactivity is defined. (author)

  17. Presentation to the Canada-US power system outage public forum

    International Nuclear Information System (INIS)

    Solar manufacturers, distributors, retailers, installers, and consultants across Canada are represented by the Canadian Solar Industries Association (CanSIA). The author clarified the solar situation in Canada, noting that Canada has a similar or better solar resource than nations who are currently solar leaders, and that few solar markets in the world today are cost-competitive without the support of government. The reliability of the electrical grid can be increased with the help of solar energy, and it can also increase the diversification of energy sources. Even during winter ice storms, solar buildings can function without an outside source of heat. Similarly, no outside source of electricity is required for such a building to function during summer blackouts. Growth of the global market for solar power exceeds 25 per cent annually. Approximately 1 per cent of Canada's electricity supply could be provided by solar through proper planning, and over 2 per cent by 2025 in Ontario. The author argued that several measures must be implemented in Canada for the country to reach its potential in support of the electrical grid. The measures include a National Renewable Energy Plan, a Renewable Portfolio Standard, net metering, feed in policy, elimination of electric rate subsidies and the introduction of time-of-day metering, and subsidies. 3 tabs

  18. Solar building

    OpenAIRE

    Zhang, Luxin

    2014-01-01

    In my thesis I describe the utilization of solar energy and solar energy with building integration. In introduction it is also mentioned how the solar building works, trying to make more people understand and accept the solar building. The thesis introduces different types of solar heat collectors. I compared the difference two operation modes of solar water heating system and created examples of solar water system selection. I also introduced other solar building applications. It is conv...

  19. Power allocation and achievable data rate in spectrum-sharing channels under adaptive primary service outage constraints

    KAUST Repository

    Yang, Yuli

    2012-09-01

    In this paper, we focus on a cognitive radio network where adaptive modulation is adopted in primary links. The gap between the primary user (PU)\\'s received signal-to-noise ratio (SNR) and the lower SNR boundary of the modulation mode that is being used, provides an interference-tolerable zone. Based on this gap, a secondary user (SU) has an increased opportunity to access the licensed spectrum and to determine the transmit power it should use to keep the PU\\'s quality-of-service (QoS) unaffected. However, since the SU cannot obtain perfect information on the PU\\'s received SNR, it has to choose an SNR point between the lower and upper boundaries of the PU\\'s current modulation mode as if this point were the real SNR received by the PU. Considering this issue, in order to quantify the effect of the SU\\'s transmissions on the PU\\'s QoS, we define the PU\\'s service outage probability and obtain its closed-form expressions by taking into account whether the peak transmit power constraint is imposed on the secondary\\'s transmission or not. Subsequently, we derive the SU\\'s achievable data rate in closed form for counterpart scenarios. Numerical results provided here quantify the relation between the PU\\'s service outage probability and the SU\\'s achievable data rate, which further demonstrate that the higher the peak transmit power a secondary transmitter can support, the better performance the cognitive radio network can achieve. © 2012 IEEE.

  20. Building 2000

    International Nuclear Information System (INIS)

    This is the first volume of Building 2000, a pilot project of the Commission's R and D-programme 'Solar Energy Applications to Buildings' with the purpose of encouraging the adoption of solar architecture in large buildings. In this first rich illustrated volume the results of the design studies illustrating passive solar architecture in buildings in the European Community are presented in particular for the building categories as mentioned in the subtitle. In a second volume, a similar series of studies is presented for the building categories: office buildings, public buildings and hotels and holiday complexes. Several Design Support Workshops were organized during the Building 2000 programme during which Building 2000 design teams could directly exchange ideas with the various design advice experts represented at these workshops. In the second part of the Building 2000 final report a summary of a selection of many reports is presented (15 papers), as produced by Design Support experts. Most of the design support activities resulted in changes of the various designs, as have been reported by the design teams in the brochures presented in the first part of this book. It is to be expected that design aids and simulation tools for passive solar options, daylighting concepts, comfort criteria etc., will be utilized more frequently in the future. This will result in a better exchange of information between the actual design practitioners and the European R and D community. This technology transfer will result in buildings with a higher quality with respect to energy and environmental issues

  1. Reason analysis for contamination of protective clothes during the first outage of unit 1 at Qinshan Nuclear Power Plant phase II

    International Nuclear Information System (INIS)

    More contamination events of protective clothes were occurred during the first outage of Unit 1 at Qinshan Nuclear Power Plant phase II. As a result, contaminated protective clothes were accumulated. This paper describes the amount and conditions of protective clothes analyses and discussies the reason of contamination. The measures for protecting protective clothes agaist contamination were put forward. (authors)

  2. Evaluation of the resilience of a full-scale down-flow hanging sponge reactor to long-term outages at a sewage treatment plant in India.

    Science.gov (United States)

    Onodera, Takashi; Takayama, Daisuke; Ohashi, Akiyoshi; Yamaguchi, Takashi; Uemura, Shigeki; Harada, Hideki

    2016-10-01

    Resilience to process outages is an essential requirement for sustainable wastewater treatment systems in developing countries. In this study, we evaluated the ability of a full-scale down-flow hanging sponge (DHS) reactor to recover after a 10-day outage. The DHS tested in this study uses polyurethane sponge as packing material. This full-scale DHS reactor has been tested over a period of about 4 years in India with a flow rate of 500 m(3)/day. Water was not supplied to the DHS reactor that was subjected to the 10-day outage; however, the biomass did not dry out because the sponge was able to retain enough water. Soon after the reactor was restarted, a small quantity of biomass, amounting to only 0.1% of the total retained biomass, was eluted. The DHS effluent achieved satisfactory removal of suspended solids, chemical oxygen demand, and ammonium nitrogen within 90, 45, and 90 min, respectively. Conversely, fecal coliforms in the DHS effluent did not reach satisfactory levels within 540 min; instead, the normal levels of fecal coliforms were achieved within 3 days. Overall, the tests demonstrated that the DHS reactor was sufficiently robust to withstand long-term outages and achieved steady state soon after restart. This reinforces the suitability of this technology for developing countries. PMID:27450993

  3. Building 2000

    International Nuclear Information System (INIS)

    This is the second volume of Building 2000, a pilot project of the Commission's R and D-programme 'Solar Energy Applications to Buildings' with the purpose of encouraging the adoption of solar architecture in large buildings. In this second rich illustrated volume the results of the design studies illustrating passive solar architecture in buildings in the European Community are presented in particular for the building categories as mentioned in the subtitle. In the first volume, a similar series of studies is presented for the building categories: schools, laboratories and universities, and sports and educational centres. Several Design Support Workshops were organized during the Building 2000 programme during which Building 2000 design teams could directly exchange ideas with the various design advice experts represented at these workshops. In the second part of the Building 2000 final report a summary of a selection of many reports is presented (11 papers), as produced by Design Support experts. Most of the design support activities resulted in changes of the various designs, as have been reported by the design teams in the brochures presented in the first part of this book. It is to be expected that design aids and simulation tools for passive solar options, daylighting concepts, comfort criteria etc., will be utilized more frequently in the future. This will result in a better exchange of information between the actual design practitioners and the European R and D community. This technology transfer will result in buildings with a higher quality with respect to energy and environmental issues

  4. Using consensus building to improve utility regulation

    International Nuclear Information System (INIS)

    The utility industry and its regulatory environment are at a crossroads. Utilities, intervenors and even public utility commissions are no longer able to initiate and sustain changes unilaterally. Traditional approaches to regulation are often contentious and costly, producing results that are not perceived as legitimate or practical. Consensus building and alternative dispute resolution have the potential to help utilities, intervenors and regulators resolve a host of regulatory issues. This book traces the decline of consensus in utility regulation and delineates current controversies. It presents the theory and practice of alternative dispute resolution in utility regulation and offers a framework for evaluating the successes and failures of attempts to employ these processes. Four regulatory cases are analyzed in detail: the Pilgrim nuclear power plant outage settlement, the use of DSM collaboratives, the New Jersey resource bidding policy and the formation of integrated resource management rules in Massachusetts

  5. Relaxation of containment: Pickering NGS-A unit 3 rehabilitation outage

    International Nuclear Information System (INIS)

    A reactor containment system provides designed barriers between radioactive sources in reactor systems and the general public. Normally, access to the reactor systems is controlled via airlocks in the Reactor Building so that the containment system integrity can be maintained unimpaired. During reactor retubing, however, a more direct access to the reactor is necessary in order that retubing operations can be conducted efficiently. The Pickering NGS containment system is described briefly together with the detailed strategy adopted to relax the guidelines governing containment, which permits a less restrictive access to the reactor. Topics discussed include prerequisite work, the control strategy and procedures employed during relaxation as well as supporting analyses. Of particular importance is the need to maintain quality and operational standards, where required, so that the containment envelope can be reestablished quickly when and if required. This paper will be of interest to all CANDU owner/operators regardless of containment design and is potentially of interest to operators of other containment designs. It is anticipated that future containment relaxations at other CANDU sites in Canada will follow this strategy as a baseline. (author). 3 tabs., 5 figs

  6. Laboratory Building.

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, Joshua M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    This report is an analysis of the means of egress and life safety requirements for the laboratory building. The building is located at Sandia National Laboratories (SNL) in Albuquerque, NM. The report includes a prescriptive-based analysis as well as a performance-based analysis. Following the analysis are appendices which contain maps of the laboratory building used throughout the analysis. The top of all the maps is assumed to be north.

  7. Dimensionamiento del refuerzo a flexión con laminados de polímeros reforzados con fibras (FRP evitando su desprendimiento prematuro

    Directory of Open Access Journals (Sweden)

    Oller, E.

    2013-12-01

    Full Text Available According to the available experimental research related to structures flexurally strengthened by bonding fiber reinforced polymer (FRP laminates, the laminate debonds in a brittle manner in most tests. This debonding failure usually initiates in the most loaded regions due the effect of intermediate cracks (intermediate crack debonding. From the beginning of this technique, several models have been developed to avoid this premature failure. However, some of them present a significant scatter in relation to the experimental data. This paper presents a comparative analysis of the existing formulations through a database of tests compiled by the authors. Afterwards, a design procedure based on a shear-bending moment interaction diagram related to intermediate crack debonding is presented. This interaction diagram depends on the maximum shear force between crack discontinuities. Finally, the proposed method is compared to the rest of the models obtaining satisfactory results when predicting the failure load.La investigación experimental de elementos de hormigón reforzados a flexión mediante la adhesión de laminados de polímeros reforzados con fibras (FRP muestra que en la mayor parte de ensayos, el laminado se desprende de forma prematura iniciándose normalmente el fallo en las regiones más solicitadas debido al efecto de las fisuras intermedias. Desde los inicios de esta técnica de refuerzo, se han desarrollado modelos para evitar este tipo de rotura, la mayoría de los cuales presentan una dispersión considerable comparando sus resultados con los experimentales. En este artículo se presenta un análisis comparativo de diferentes formulaciones existentes a partir de una base de datos de ensayos recopilada por los autores. Posteriormente, se propone un método de dimensionamiento basado en un diagrama de interacción cortante-flexión asociado al desprendimiento del refuerzo, que depende de la máxima fuerza rasante transmitida entre

  8. Quantification of risk considering external events on the change of allowed outage time and the preventive maintenance during power operation

    International Nuclear Information System (INIS)

    In this study, for the major safety systems of Ulchin Units 3/4, we quantify the risk on the change of AOT and the PM during power operation to identify the effects on the results of external events PSA when nuclear power plant changes such as allowed outage time are requested. The systems for which the risks on the change of allowed outage time are quantified are High Pressure Safety Injection System (HPSIS), Containment Spray System (CSS), and Emergency Diesel Generator (EDG). The systems for which the risks on the PM during power operation are Low Pressure Safety Injection System (LPSIS), CSS, EDG, Essential Service Water System (ESWS). Following conclusions can be obtained through this study: 1)The increase of core damage frequency (ΔCDF) on the change of AOT and the conditional core damage probability (CCDP) on the on-line PM of each system are differently quantified according to the cases of considering only internal events or only external events. . 2)It is expected that the quantification of risk including internal and external events is advantageous for the licensee of NPP if the regulatory acceptance criteria for the technical specification changes are relatively set up. However, it is expected to be disadvantageous for the licensee if the acceptance criteria are absolutely set up. 3)It is expected that the conduction on the quantification of only a fire event is sufficient when the quantification of external events PSA model is required for the plant changes of Korea Standard NPPs. 4)It is expected that the quantification of the increase of core damage frequency and the incremental conditional core damage probability on technical specification changes are not needed if the quantification results of those considering only internal events are below regulatory acceptance criteria and the external events PSA results are not greatly affected by the system availability. However, it is expected that the quantification of risk considering external events on

  9. DEFECTS AND FAILURES OF JOINTS OF HISTORIC ROOF TRUSSES AND POSSIBILITIES OF USING FRP MATERIALS IN THEIR REHABILITATION AND STABILIZATION

    Directory of Open Access Journals (Sweden)

    Tomáš Čejka

    2015-10-01

    Full Text Available The survey of selected historic roof trusses performed within the NAKI DF12P01OVV037project revealed numerous failures and defects of joints of roof truss elements of historic and listed buildings. Based on the results of the survey, the article outlines potential rehabilitation and reinforcement techniques of joints of roof truss elements in which the most frequent defects and failures were found using composite fabrics based on high-strength carbon fibres and epoxy resin (CFRP.

  10. Biochemical characterization of NfsA, the Escherichia coli major nitroreductase exhibiting a high amino acid sequence homology to Frp, a Vibrio harveyi flavin oxidoreductase.

    Science.gov (United States)

    Zenno, S; Koike, H; Kumar, A N; Jayaraman, R; Tanokura, M; Saigo, K

    1996-01-01

    We identified the nfsA gene, encoding the major oxygen-insensitive nitroreductase in Escherichia coli, and determined its position on the E. coli map to be 19 min. We also purified its gene product, NfsA, to homogeneity. It was suggested that NfsA is a nonglobular protein with a molecular weight of 26,799 and is associated tightly with a flavin mononucleotide. Its amino acid sequence is highly similar to that of Frp, a flavin oxidoreductase from Vibrio harveyi (B. Lei, M. Liu, S. Huang, and S.-C. Tu, J. Bacteriol. 176:3552-3558, 1994), an observation supporting the notion that E. coli nitroreductase and luminescent-bacterium flavin reductase families are intimately related in evolution. Although no appreciable sequence similarity was detected between two E. coli nitroreductases, NfsA and NfsB, NfsA exhibited a low level of the flavin reductase activity and a broad electron acceptor specificity similar to those of NfsB. NfsA reduced nitrofurazone by a ping-pong Bi-Bi mechanism possibly to generate a two-electron transfer product. PMID:8755878

  11. Risk-based evaluation of allowed outage time and surveillance test interval extensions for nuclear power plants

    International Nuclear Information System (INIS)

    The main goal of this work is, through the use of Probabilistic Safety Analysis (PSA), to evaluate Technical Specification (TS) Allowed Outage Times (AOT) and Surveillance Test Intervals (STI) extensions for Angra 1 nuclear power plant. PSA has been incorporated as an additional tool, required as part of NPP licensing process. The risk measure used in this work is the Core Damage Frequency (CDF), obtained from the Angra 1 PSA Level 1. AOT and STI extensions are calculated for the Safety Injection System (SIS), Service water System (SAS) and Auxiliary Feedwater System (AFS) through the use of SAPHIRE code. In order to compensate for the risk increase caused by the extensions, compensatory measures as test of redundant train prior to entering maintenance and staggered test strategy are proposed. Results have shown that the proposed AOT extensions are acceptable for the SIS and SAS with the implementation of compensatory measures. The proposed AOT extension is not acceptable for the AFS. The STI extensions are acceptable for all three systems. (author)

  12. Building Procurement

    DEFF Research Database (Denmark)

    Andersson, Niclas

    2007-01-01

    ‘The procurement of construction work is complex, and a successful outcome frequently elusive’. With this opening phrase of the book, the authors take on the challenging job of explaining the complexity of building procurement. Even though building procurement systems are, and will remain, complex...... despite this excellent book, the knowledge, expertise, well-articulated argument and collection of recent research efforts that are provided by the three authors will help to make project success less elusive. The book constitutes a thorough and comprehensive investigation of building procurement, which......, which gives the book a challenging contribution to the existing body of knowledge....

  13. On the Efficient Simulation of the Distribution of the Sum of Gamma-Gamma Variates with Application to the Outage Probability Evaluation Over Fading Channels

    KAUST Repository

    Chaouki Ben Issaid

    2016-06-01

    The Gamma-Gamma distribution has recently emerged in a number of applications ranging from modeling scattering and reverbation in sonar and radar systems to modeling atmospheric turbulence in wireless optical channels. In this respect, assessing the outage probability achieved by some diversity techniques over this kind of channels is of major practical importance. In many circumstances, this is intimately related to the difficult question of analyzing the statistics of a sum of Gamma-Gamma random variables. Answering this question is not a simple matter. This is essentially because outage probabilities encountered in practice are often very small, and hence the use of classical Monte Carlo methods is not a reasonable choice. This lies behind the main motivation of the present work. In particular, this paper proposes a new approach to estimate the left tail of the sum of Gamma-Gamma variates. More specifically, we propose a mean-shift importance sampling scheme that efficiently evaluates the outage probability of L-branch maximum ratio combining diversity receivers over Gamma-Gamma fading channels. The proposed estimator satisfies the well-known bounded relative error criterion, a well-desired property characterizing the robustness of importance sampling schemes, for both identically and non-identically independent distributed cases. We show the accuracy and the efficiency of our approach compared to naive Monte Carlo via some selected numerical simulations.

  14. The use of success path planning to reduce shutdown risk during a dual unit outage at FPL's Turkey Point Power Plant

    International Nuclear Information System (INIS)

    This paper discusses the merits of using success path planning to direct nuclear power plant operators in their recovery actions from plant transients or equipment malfunctions that occur during plant outages. Florida Power and Light Company (FPL) prepared for an eleven month dual unit outage which involved the electrical distribution system. During different phases of the outage, up to half of the normal power distribution would be out of service. The removal of decay heat from the spent nuclear fuel from both nuclear units became a major planning focus. To reduce the risk of loosing decay heat removal functions. FPL used success path planning to aid the operators in the recovery of decay heat removal functions should an electrical transient occur. A open-quotes success pathclose quotes is the alignment of equipment, valves, piping and electrical power which will restore a plant function which was lost due to a transient or equipment malfunction. There can be more than one success path for a given transient. This method of planning to deal with transients was chosen due to the large amount of equipment that would be out-of-service and tracked according to the plant's Technical Specifications. To decrease the response time to transients, the success paths were proceduralized and included training of the individuals involved with the alignments

  15. Outage Performance Analysis of Relay Selection Schemes in Wireless Energy Harvesting Cooperative Networks over Non-Identical Rayleigh Fading Channels †

    Science.gov (United States)

    Do, Nhu Tri; Bao, Vo Nguyen Quoc; An, Beongku

    2016-01-01

    In this paper, we study relay selection in decode-and-forward wireless energy harvesting cooperative networks. In contrast to conventional cooperative networks, the relays harvest energy from the source’s radio-frequency radiation and then use that energy to forward the source information. Considering power splitting receiver architecture used at relays to harvest energy, we are concerned with the performance of two popular relay selection schemes, namely, partial relay selection (PRS) scheme and optimal relay selection (ORS) scheme. In particular, we analyze the system performance in terms of outage probability (OP) over independent and non-identical (i.n.i.d.) Rayleigh fading channels. We derive the closed-form approximations for the system outage probabilities of both schemes and validate the analysis by the Monte-Carlo simulation. The numerical results provide comprehensive performance comparison between the PRS and ORS schemes and reveal the effect of wireless energy harvesting on the outage performances of both schemes. Additionally, we also show the advantages and drawbacks of the wireless energy harvesting cooperative networks and compare to the conventional cooperative networks. PMID:26927119

  16. Reactor building

    International Nuclear Information System (INIS)

    The present invention concerns a structure of ABWR-type reactor buildings, which can increase the capacity of a spent fuel storage area at a low cost and improved earthquake proofness. In the reactor building, the floor of a spent fuel pool is made flat, and a depth of the pool water satisfying requirement for shielding is ensured. In addition, a depth of pool water is also maintained for a equipment provisionally storing pool for storing spent fuels, and a capacity for a spent fuel storage area is increased by utilizing surplus space of the equipment provisionally storing pool. Since the flattened floor of the spent fuel pool is flushed with the floor of the equipment provisionally storing pool, transfer of horizontal loads applied to the building upon occurrence of earthquakes is made smooth, to improve earthquake proofness of the building. (T.M.)

  17. Building Languages

    Science.gov (United States)

    ... family's native language) is taught as the child's second language through reading, writing, speech, and use of residual ... that parents can use to help their child learn language. There are many types of building blocks, and ...

  18. Observations and insights from the Grand Gulf Low Power and Shutdown Study of POS 5 during a refueling outage

    International Nuclear Information System (INIS)

    With the completion of the documentation of the results from the Grand Gulf Nuclear Power Plant Low Power and Shutdown (LP and S) Project funded by the US Nuclear Regulatory Commission, detailed probabilistic risk assessment (PRA) information from a boiling water reactor for a specific time period in LP and S conditions became available for examination. This paper summarizes why LP and S conditions should be examined and how the particular operational state was selected. It also summarizes observations and insights extracted from an examination of: (1) results in the LP and S documentation, (2) the specific models and assumptions used in the LP and S analyses, (3) selected results from the full power analysis, (4) the experience of the analysts who performed the original LP and S study, and (5) results from sensitivity calculations to help determine the impact that model assumptions and data values had on the results from the original LP and S analysis. Observations and insights on core damage frequency and aggregate risk (early fatalities and total latent cancer fatalities) associated with operations during plant operational state 5 (i.e., basically cold shutdown as defined by Technical Specifications) during a refueling outage for traditional internal events are provided. In addition, a discussion of similarities and differences between full power accidents and accidents during LP and S conditions is provided. As part of this discussion, core damage frequency and risks results are presented on a per hour and per calendar year basis, allowing alternative perspectives on both the core damage frequency and risk associated with these two operational states

  19. When does unreliable grid supply become unacceptable policy? Costs of power supply and outages in rural India

    International Nuclear Information System (INIS)

    Despite frequent blackouts and brownouts, extension of the central grid remains the Indian government's preferred strategy for the country's rural electrification policy. This study reports an assessment that compares grid extension with distributed generation (DG) alternatives, based on the subsidies they will necessitate, and costs of service interruptions that are appropriate in the rural Indian context. Using cross-sectional household expenditure data and region fixed-effects models, average household demand is estimated. The price elasticity of demand is found to be in the range of −0.3 to −0.4. Interruption costs are estimated based on the loss of consumer surplus due to reduced consumption of electric lighting energy that results from intermittent power supply. Different grid reliability scenarios are simulated. Despite the inclusion of interruption costs, standalone DG does not appear to be competitive with grid extension at distances of less than 17 km. However, backing up unreliable grid service with local DG plants is attractive when reliability is very poor, even in previously electrified villages. Introduction of energy efficient lighting changes these economics, and the threshold for acceptable grid unreliability significantly reduces. A variety of polices to promote accelerated deployment and the wider adoption of improved end-use efficiency, warrant serious consideration. - Highlights: • We question the reliance on conventional grid in rural electricity supply in India. • Alternatives compared through government subsidies and consumer interruption costs. • Interruption costs are estimated based on loss of consumer surplus due to outages. • Augmenting unreliable grid with local biomass or diesel based backups preferable. • With efficient lighting, standalone biomass plants are optimal at very low distances

  20. Assessment of risks associated with the extension of allowed outage times for UCN 3and4 SIT and LPSI

    International Nuclear Information System (INIS)

    As a part of risk-informed application study, assessment of risks associated with extending the allowed outage times (AOT) for the safety injection tank (SIT) and the low pressure safety injection (LPSI) system of UCN 3and4 was performed. Using the UCN 3and4 PSA model along with deterministic and operational considerations, the AOT extensions from 1 hour to 24 hours for one inoperable SIT, and from 3 days to 7 days for a single LIPS subtrain were evaluated from the view poing of various plant risks. The risks evaluated in this study include at-power risk, mode transition risk, and shutdown risk. In the assessment of the at-power risk, the single AOT risks for both corrective and preventive maintenance were independently evaluated based on the conditional CDFs and AOT durations. The mode transition risk, which could be avoided if extended AOT were used, was evaluated by modifying the PSA model based on realistic plant operation during mode transition. Regarding the shutdown risk, the sensitivity of shutdowm risk to the improved LPSI system reliability by preventive maintenance at power was evaluated. In addition, the impact of the AOT change on the plant Large Early Release Frequency (LERF) was also qualitatively assessed. Results of the risk assessment showed that the at-power risks associated with the extended AOT for SIT and LPSI system were negligible and these risks would be offset by a combination of avoided mode transition risk and implementation of appropriate compensatory measures. Several compensatory measures, which can be taken when the extended AOT is utilized, are suggested. (author)