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Sample records for plant outages volume

  1. Nuclear Plant Integrated Outage Management

    International Nuclear Information System (INIS)

    Gerstberger, C. R.; Coulehan, R. J.; Tench, W. A.

    1992-01-01

    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

  2. Nuclear power plant outage optimisation strategy

    International Nuclear Information System (INIS)

    2002-10-01

    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

  3. Nuclear power plant outages

    International Nuclear Information System (INIS)

    1998-01-01

    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

  4. Management strategies for nuclear power plant outages

    International Nuclear Information System (INIS)

    2006-01-01

    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

  5. Nuclear Power Plant Outage Optimization Strategy. 2016 Edition

    International Nuclear Information System (INIS)

    2016-10-01

    This publication is an update of IAEA-TECDOC-1315, Nuclear Power Plant Outage Optimisation Strategy, which was published in 2002, and aims to communicate good outage management practices in a manner that can be used by operators and utilities in Member States. Nuclear power plant outage management is a key factor for safe and economic nuclear power plant performance. This publication discusses plant outage strategy and how this strategy is actually implemented. The main areas that are important for outage optimization that were identified by the utilities and government organizations participating in this report are: 1) organization and management; 2) outage planning and preparation; 3) outage execution; 4) safety outage review; and 5) counter measures to avoid the extension of outages and to facilitate the work in forced outages. Good outage management practices cover many different areas of work and this publication aims to communicate these good practices in a way that they can be used effectively by operators and utilities

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

    International Nuclear Information System (INIS)

    2006-04-01

    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

  7. 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

  8. Planning and management of outages in nuclear power plants

    International Nuclear Information System (INIS)

    Sica, G.F.; Fusari, W.; Reginelli, A.

    1984-01-01

    At present the Ente Nazionale per l'Energia Elettrica (ENEL) operates three nuclear power plants, only one of which belongs to the new generation, i.e. the Caorso Nuclear Power Plant which has been in commercial operation since December 1981. Outage planning, implementation and analysis are very important in order to minimize the shutdown time and thus improve plant availability, which is of particular importance for a large nuclear power plant. Such activities are very complicated because of the large number of jobs that have to be performed in accordance with detailed written procedures and which have to be properly documented and controlled. Large off-site resources are required which have to be accurately interfaced with on-site staff. The ENEL is making a great effort to define both the administrative and technical aspects of refuelling outages. As outage planning requires the availability and handling of a large amount of data and information, a maintenance information system that has been widely used in conventional plants was applied, with some modifications made especially for the Caorso Nuclear Power Plant. After two years the following results have been achieved: a large number of raw and processed data are now available, the first refuelling outage was carried out with few problems and according to schedule, and the second refuelling outage, based on the experience of the first, required somewhat less preparation and is developing well even though many special activities have had to be scheduled. The ENEL believes that the efforts made in the planning and management areas will pay off in terms of the short duration, smoothness and economy of further outages, both for Caorso and for future plants. (author)

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

    International Nuclear Information System (INIS)

    Thomasson, F.R.

    1978-09-01

    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

  10. Study on optimization of normal plant outage work plan for nuclear power plants

    International Nuclear Information System (INIS)

    Aoki, Takayuki; Kodama, Noriko; Takase, Kentaro; Miya, Kenzo

    2011-01-01

    This paper discusses maintenance optimization in maintenance implementation stage following maintenance planning stage in nuclear power plants and proposes a methodology to get an optimum maintenance work plan. As a result of consideration, the followings were obtained. (1) The quantitative evaluation methodology for optimizing maintenance work plan in nuclear power plants was developed. (2) Utilizing the above methodology, a simulation analysis of maintenance work planning for BWR's PLR and RHR systems in a normal plant outage was performed. Maintenance cost calculation in several cases was carried out on the condition of smoothening man loading over the plant outage schedule as much as possible. (3) As a result of the simulation, the economical work plans having a flat man loading over the plant outage schedule were obtained. (author)

  11. Options for shortening nuclear power plant refueling outages

    International Nuclear Information System (INIS)

    Kastl, H.

    2001-01-01

    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. Driving for shorter outages

    International Nuclear Information System (INIS)

    Tritch, S.

    1996-01-01

    Nuclear plant outages are necessary to complete activities that cannot be completed during the operating cycle, such as steam generator inspection and testing, refueling, installing modifications, and performing maintenance tests. The time devoted to performing outages is normally the largest contributor to plant unavailability. Similarly, outage costs are a sizable portion of the total plant budget. The scope and quality of work done during outages directly affects operating reliability and the number of unplanned outages. Improved management and planning of outages enhances the margin of safety during the outage and results in increased plant reliability. The detailed planning and in-depth preparation that has become a necessity for driving shorter outage durations has also produced safer outages and improved post-outage reliability. Short outages require both plant and vendor management to focus on all aspects of the outage. Short outage durations, such as 26 days at South Texas or 29 days at North Anna, require power plant inter-department and intra-department teamwork and communication and vendor participation. In this paper shorter and safer outage at the 3-loop plants in the United States are explained. (J.P.N.)

  13. Balance-of-plant outage availability study. Phase I. Extension report. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Thomasson, F.R.

    1978-09-01

    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.

  14. Good practices for outage management in nuclear power plants

    International Nuclear Information System (INIS)

    1991-09-01

    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

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

    International Nuclear Information System (INIS)

    Paavola, M.

    1998-01-01

    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)

  16. Approach to shortening duration of nuclear plant refueling outage

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Yoshiharu; Nakanishi, Tooru [Mitsubishi Heavy Industries Ltd., Kobe (Japan). Kobe Shipyard and Machinery Works; Yoshihara, Seiichi; Kanbara, Masayuki; Yamanaka, Misao; Shimizu, Takeshi

    1998-07-01

    This paper summarizes the mission role of the MHI in-house project team for a shorter outage duration for PWR plants operating in Japan and its results. The major tasks of project team are benchmarking to develop outage performance goals, and develop recommendation packages for outage enhancement covering field procedures and tooling betterment. An optimization study for maintenance tasks was also carried out. This paper highlights the results of efforts the activities of the project team. (author)

  17. Questions and perceptions about nuclear power plant outages

    International Nuclear Information System (INIS)

    Mc Donald, R.P.

    1985-01-01

    The most commonly used measure of nuclear power plant productivity is ''availability'' which is usually construed to be the percentage of time in a given period that a nuclear unit is actually tied to a grid supplying electrical power. When a unit is not tied to a grid, it is in an ''outage'' condition, possibly being shutdown, refueled, repaired, or in some stage of startup. There are some very positive by-products of well performed outages in addition to cost and availability enhancements: almost all supervisory and engineering personnel participate in planning and preparations. This approach promotes the professional and leadership development of each person, the supervisors and engineers participate in a competitive venture as a team and enjoy and benefit from comparative interactions with other utilities, perhaps the greatest benefit reaped from the development of outage management expertise is the improved ability to handle unexpected plant problems

  18. 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.

  19. Outage information system

    International Nuclear Information System (INIS)

    Svengren, Haakan; Meyer, Brita Diskerud

    2005-09-01

    Today's control room systems are designed to operate during power operation, and there is clearly a need for a system to support control room personnel in automatically supervising the status of the plant during the outage period. In order to improve the supervision of Nuclear Power Plants during outages, three prototypes of the Outage Information system have been designed by the Halden Project, one for PWR and two for BWR. The Outage Information System is presented on a large screen, centrally placed in the control room. There will be a PC connected to manage the system. By using signals from the process as input to logic diagrams reflecting the plant's Safety Technical Specifications, the system automatically is supervising that requirements in Safety Technical Specifications are fulfilled during all plant states of the outage period. The system also automatically gives an overview of the status of safety systems and electrical bus bars. Alarm will occur if a requirement in the Safety Technical Specifications is not fulfilled or if a component planned to be ready for operation, is inoperable. In addition, selected measurements being important during the outage period are presented on the large screen. Which measurements and in which way the values will be presented, depends on the plant's control room design and work practice. (Author)

  20. 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

  1. Loss of benefits resulting from nuclear-power-plant outages. Volume 1. Approach and analysis

    International Nuclear Information System (INIS)

    Buehring, W.A.; Peerenboom, J.P.

    1982-03-01

    This report discusses and analyzes some of the important consequences of nuclear-power-plant unavailability, and quantifies a number of technical measures of loss of benefits that may help the Nuclear Regulatory Commission make decisions involving nuclear-power-plant licensing and operation. The consequences include increased costs of system generation, increased demand for nonnuclear and often scarce fuels, and reduced system reliability. Argonne National Laboratory (ANL) developed case studies to investigate the effects of hypothetical nuclear-plant shutdowns. The studies developed quantitative measures of both short- and long-term economic, fuel use, and reliability effects that could result from the unavailability of nuclear generating units. Results showed that production costs (fuel costs plus operation and maintenance costs) increase significantly whenever an operating reactor is shut down. Production-cost increases ranged from less than 10% to over 60%; the normalized increases for the first year of reactor outage ranged from $0.125 million per MWe-year to $0.33 million per MWe-year

  2. Outage planning in Japan

    International Nuclear Information System (INIS)

    Nedderman, John.

    1997-01-01

    Nuclear plant operators in Japan are constrained to keep refuelling and maintenance outages to a minimum by the regulation limiting operating cycles to no longer than 13 months. Outage planning by two contrasting operators is described. Hokkaido Electric, which operates only one plant, Tomari, with two PWRs, plans to reduce outage time from the present 65 days in two stages. Detailed review of previous outage schedules has shown that a reduction to 59 days should be achievable by careful planning without any fundamental changes. The second reduction to 49 days will require such measures as relaxing water purity standards, rescheduling fuel unloading and loading shifts and speeding up eddy current testing of primary equipment by using steam generator nozzle dams. Kansai Electric, operating 11 PWRs at three plants, has scope for reducing outages at all of its units using a range of measures. Steam generator replacement in the seven oldest reactors, completed in July 1997, is by far the most significant of these and is expected to save 64 days repair time in a previous average outage time of 131 days. (UK)

  3. Outage reduction of Hamaoka NPS

    International Nuclear Information System (INIS)

    Hida, Shigeru; Anma, Minoru

    1999-01-01

    In the Hamaoka nuclear power plant, we have worked on the outage reduction since 1993. In those days, the outage length in Hamaoka was 80 days or more, and was largely far apart from excellent results of European and American plants about the 30days. A concrete strategy to achieve the reduction process is the extension of working hours, the changing work schedule control unit for every hour, the equipment improvements, and the improvements of work environments, etc. We executed them one by one reflecting results. As a result, we achieved the outage for 57 days in 1995. Starting from this, we acquired the further outage reduction one by one and achieved the outage for 38 days in 1997 while maintaining safety and reliability of the plant. We advance these strategies further and we will aim at the achievement of the 30·35 days outage in the future. (author)

  4. Framatome ANP outage optimization support solutions

    International Nuclear Information System (INIS)

    Bombail, Jean Paul

    2003-01-01

    Over the last several years, leading plant operators have demonstrated that availability factors can be improved while safety and reliability can be enhanced on a long-term basis and operating costs reduced. Outage optimization is the new term being used to describe these long-term initiatives through which a variety of measures aimed at shortening scheduled plant outages have been developed and successfully implemented by these leaders working with their service providers who were introducing new technologies and process improvements. Following the leaders, all operators now have ambitious outage optimization plans and the median and average outage duration are decreasing world-wide. Future objectives are even more stringent and must include plant upgrades and component replacements being performed for life extension of plant operation. Outage optimization covers a broad range of activities from modifications of plant systems to faster cool down rates to human behavior improvements. It has been proven to reduce costs, avoid unplanned outages and thus support plant availability and help to ensure the utility's competitive position in the marketplace

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

    International Nuclear Information System (INIS)

    2004-05-01

    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. Refueling outage services in Spanish Nuclear Power Plants

    International Nuclear Information System (INIS)

    Landete, J. L.; Soto, M.; Nunuez, A.

    2007-01-01

    DOMINGUIS Group, through its 75 years of business development, has positioned as the Spanish leader Group in Services for the Nuclear Energy and Petrochemical Sectors. In this article, we present the most significant services summary that, through the companies that constitute DOMINGUIS Group, we have developed in Refueling Outage in Spanish Nuclear Power Plants. (Author)

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

    International Nuclear Information System (INIS)

    Laplatney, Jere; Hwang, Euiyoub

    2006-01-01

    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

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

    International Nuclear Information System (INIS)

    Mayers, J.B.; Soth, L.G.

    1978-04-01

    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

  9. Outage optimization - the US experience and approach

    International Nuclear Information System (INIS)

    LaPlatney, J.

    2007-01-01

    Sustainable development of Nuclear Energy depends heavily on excellent performance of the existing fleet which in turn depends heavily on the performance of planned outages. Some reactor fleets, for example Finland and Germany, have demonstrated sustained good outage performance from their start of commercial operation. Others, such as the US, have improved performance over time. The principles behind a successful outage optimization process are: -) duration is not sole measure of outage success, -) outage work must be performed safely, -) scope selection must focus on improving plant material condition to improve reliability, -) all approved outage work must be completed, -) work must be done cost effectively, -) post-outage plant reliability is a key measure of outage success, and -) outage lessons learned must be effectively implemented to achieve continuous improvement. This approach has proven its superiority over simple outage shortening, and has yielded good results in the US fleet over the past 15 years

  10. Major outage trends in light water reactors. Interim report

    International Nuclear Information System (INIS)

    Burns, E.T.

    1978-04-01

    The report is a summary of the major outages which occurred in light water reactor plants during the period January 1971 through June 1977. Only those outages greater than 100 hours duration (exclusive of refueling outages) are included in the report. The trends in outages related to various reactor systems and components are presented as a function of plant age, and alternatively, calendar year. The principal contributors to major outages are ranked by their effect on the overall outage time for PWRs and BWRs. In addition, the outage history of each operating nuclear plant greater than 150 MWe is presented, along with a brief summary of those outages greater than two months duration

  11. Outages planning

    International Nuclear Information System (INIS)

    Blanquer, N.

    2010-01-01

    The reason of a nuclear power plant outage seems easy. Replace 1/3 of the total core fuel inside reactor for a new, store the old one in a pool and shuffle the rest 2/3 in other positions in the core to optimize fuel burn up. Also is needed to make the preventive, corrective and conservative maintenance, the selected design changes and the regulatory and technical requirements for equipment and systems. To make the plant outage strategy for all the above pack with nuclear safety not challenged is the objective of this article for the Spanish Nuclear Society magazine. (Author)

  12. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Analysis of core damage frequency from internal events for Plant Operational State 5 during a refueling outage. Volume 2, Part 3: Internal Events Appendices I and J

    Energy Technology Data Exchange (ETDEWEB)

    Yakle, J. [Science Applications International Corp., Albuquerque, NM (United States); Darby, J. [Science and Engineering Associates, Inc., Albuquerque, NM (United States); Whitehead, D.; Staple, B. [Sandia National Labs., Albuquerque, NM (United States)

    1994-06-01

    This report provides supporting documentation for various tasks associated with the performance of the probablistic risk assessment for Plant Operational State 5 during a refueling outage at Grand Gulf, Unit 1 as documented in Volume 2, Part 1 of NUREG/CR-6143.

  13. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Analysis of core damage frequency from internal events for Plant Operational State 5 during a refueling outage. Volume 2, Part 3: Internal Events Appendices I and J

    International Nuclear Information System (INIS)

    Yakle, J.; Darby, J.; Whitehead, D.; Staple, B.

    1994-06-01

    This report provides supporting documentation for various tasks associated with the performance of the probablistic risk assessment for Plant Operational State 5 during a refueling outage at Grand Gulf, Unit 1 as documented in Volume 2, Part 1 of NUREG/CR-6143

  14. Standard plants, standard outages: the EdF approach

    International Nuclear Information System (INIS)

    Miron, J.L.

    1991-01-01

    At the end of 1990 Electricite de France had carried out a total of 350 PWR refuelling outages. Although the French units are standardized the routine of the outages are not all the same. The major influences on outages were: setting up new organizations to apply quality assurance regulations; improving systematic experience feedback; incorporating modifications in the outage schedules; assumilation of computerized maintenance management by the sites. (author)

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

    International Nuclear Information System (INIS)

    Telle, M.A.; Huez, D.; Niedbala, J.M.; Auclair, J.; Canales, J.P.; Duverge, C.; Forest, H.; Gerondal, M.; Paris, P.M.; Renault, J.C.; Bossevain, L.; Blaise, P.; Blanc, M.C.; Goldberg, M.; Charpak, Y.

    1995-01-01

    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

  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)

    St. Germain, Shawn W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Farris, Ronald K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Whaley, April M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Medema, Heather D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gertman, David I. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    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. The purpose of this research is to improve management of nuclear power plant (NPP) outages through the development of an advanced outage control center (AOCC) that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. This technical report for industry implementation outlines methods and considerations for the establishment of an AOCC. This report provides a process for implementation of a change management plan, evaluation of current outage processes, the selection of technology, and guidance for the implementation of the selected technology. Methods are presented for both adoption of technologies within an existing OCC and for a complete OCC replacement, including human factors considerations for OCC design and setup.

  17. Unit availability not affected by extending outage cycles

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.J.

    2003-03-01

    To improve their economic dispatch position, more and more plant owners are extending the intervals between major outages for boilers from one year to 18-24 months and for steam turbine up to 12 years. In many instances, extended outage cycles have resulted in no loss in availability or increases in forced outages. The article discusses outage scheduling at Tucson Electric Power's Springville coal-fired plant, the Panther Creek Energy Facility in Pennsylvania, and at Tennessee Valley Authority's coal-fired power plants. 1 fig.

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

    International Nuclear Information System (INIS)

    2001-12-01

    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)

  19. Olkiluoto 1 and 2 - Plant efficiency improvement and lifetime extension-project (PELE) implemented during outages 2010 and 2011

    Energy Technology Data Exchange (ETDEWEB)

    Kosonen, M.; Hakola, M. [Teollisuuden Voima Oyj, F- 27160 Eurajoki (Finland)

    2012-07-01

    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

  20. Olkiluoto 1 and 2 - Plant efficiency improvement and lifetime extension-project (PELE) implemented during outages 2010 and 2011

    International Nuclear Information System (INIS)

    Kosonen, M.; Hakola, M.

    2012-01-01

    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

  1. Resolving piping analysis issues to minimize impact on installation activities during refueling outage at nuclear power plants

    International Nuclear Information System (INIS)

    Bhavnani, D.

    1996-01-01

    While it is required to maintain piping code compliance for all phases of installation activities during outages at a nuclear plant, it is equally essential to reduce challenges to the installation personnel on how plant modification work should be performed. Plant betterment activities that incorporate proposed design changes are continually implemented during the outages. Supporting analysis are performed to back these activities for operable systems. The goal is to reduce engineering and craft man-hours and minimize outage time. This paper outlines how plant modification process can be streamlined to facilitate construction teams to do their tasks that involve safety related piping. In this manner, installation can proceed by minimizing on the spot analytical effort and reduce downtime to support the proposed modifications. Examples are provided that permit performance of installation work in any sequence. Piping and hangers including the branch lines are prequalified and determined operable. The system is up front analyzed for all possible scenarios. The modification instructions in the work packages is flexible enough to permit any possible installation sequence. The benefit to this approach is large enough in the sense that valuable outage time is not extended and on site analytical work is not required

  2. Nuclear outages: an approach to project controls

    International Nuclear Information System (INIS)

    Bryson, R.

    1985-01-01

    The annual budget for maintaining and operating a nuclear power plant has risen dramatically over the past 5 years. NRC-mandated plant improvements and outage related expenses are often cited to be the main contributors to these escalating budgets. Nuclear utilities have responded by developing programs to improve plant availability and outage costs through improved outage performance. Utilities recognize that for capital improvements the program to control costs does no begin with outage planning, but rather more appropriately up front during the engineering phase. To support their management objectives, utilities have been developing comprehensive project control systems for concurrently reducing capital expenditures, outage-related costs, and time. This paper provides an approach to project controls that, rather than using one all inclusive comprehensive system, requires five separate monitoring systems - one for each phase of an activity's life cycle. Through the integration of these discrete but interrelated systems, utility management acquires the necessary tools for comprehensive planning and control of their modification program and effective detailed monitoring for all outage-related activities

  3. Diablo Canyon refueling outage program

    International Nuclear Information System (INIS)

    McLane, W.B.; Irving, T.L.

    1991-01-01

    Management of outages has become one of the most talked about subjects in the nuclear power industry in the past several years. Many utilities do not perform refueling outages very well or in the past have had some outages that they would not like to repeat and in some cases do not even like to think about. With the growing cost of energy and the demands placed on utilities to improve capacity factors, it is very easy for management to focus on shortening refueling outage durations as a prime objective in improving overall corporate performance. So it is with Pacific Gas and Electric Company and the Diablo Canyon power plant. A review of their refueling outage performance reflects a utility that is responding to the nuclear industry's call for improved outage performance

  4. Maintenance and Outage Management Assessment (MOMA)

    International Nuclear Information System (INIS)

    2005-01-01

    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

  5. 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.

  6. Analysis of scrams and forced outages at boiling water reactors

    International Nuclear Information System (INIS)

    Earle, R.T.; Sullivan, W.P.; Miller, K.R.; Schwegman, W.J.

    1980-07-01

    This report documents the results of a study of scrams and forced outages at General Electric Boiling Water Reactors (BWRs) operating in the United States. This study was conducted for Sandia Laboratories under a Light Water Reactor Safety Program which it manages for the United States Department of Energy. Operating plant data were used to identify the causes of scrams and forced outages. Causes of scrams and forced outages have been summarized as a function of operating plant and plant age and also ranked according to the number of events per year, outage time per year, and outage time per event. From this ranking, identified potential improvement opportunities were evaluated to determine the associated benefits and impact on plant availability

  7. 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)

    1985-03-01

    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

  8. Power plant and utility performance: how world-record outages are being achieved in the USA

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    Two record-breaking refuelling outages at power reactors in the USA are described. The first, at Browns Ferry 3 BWR, was accomplished in 19 days 39 minutes - a shorter time than for an General Electric BWR anywhere in the world hitherto. The management attribute this success to planning, personnel and performance. As well as refuelling, inspections and maintenance, major modifications were carried out. These included the completion of the installation of digital feedwater reactor level control and digital feedwater heater level control. The second outage, at South Texas Project 2 BWR, at 17 days 14 hours and 10 minutes was the fastest yet recorded for any US nuclear unit. This achievement is ascribed to excellent outage preparation and scheduling, the superior condition of the plant equipment and teamwork and safety consciousness on behalf of the plant personnel. Finally, brief consideration is given to the nuclear performance recovery programme of Commonwealth Edison and Ontario Hydro Nuclear. (UK)

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

    International Nuclear Information System (INIS)

    Stroebeck, Einar; Olausson, Jesper; Van Gemst, Paul

    1998-01-01

    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)

  10. Long-term optimization of outage performance

    International Nuclear Information System (INIS)

    Huemmeler, Alexander; Jakobs, Norbert; Seifert, Siegfried

    2003-01-01

    Deregulation of the power markets and the accompanying pressure on electricity prices have forced all electric utilities to reduce their power generating costs in order to be able to hold their own in the new market environment. This has also particularly affected the operators of nuclear power plants since they have to compete against the lower power generating costs of fossil-fired combined-cycle power plants and, in Germany are faced with a difficult political climate. The areas identified as having the greatest cost-cutting potential were fuel costs, operating costs and measures to increase plant availability. The main objective behind increasing plant availability was not only to improve the already high standard of operational reliability and plant safety even further, but also to significantly shorten the downtime needed for annual refueling outages. A variety of measures aimed at shortening scheduled plant outages have thus been developed and successfully implemented by nuclear plant operators. At the same time, process improvements and new technologies have been introduced by the service providers. Both initiatives together have contributed towards substantially reducing outage time and cost. (author)

  11. Refueling outage data collection and analysis

    International Nuclear Information System (INIS)

    Harshaw, K.; Quilliam, J.; Brinsfield, W.; Jeffries, J.

    1993-07-01

    This report summarizes the results of an EPRI project to compile an industry generic refueling outage database applicable to alternate (non-full-power) modes of shutdown conditions at nuclear power plants. The project team evaluated five outages at two BWR plants. They obtained data primarily from control room logs, outage schedules, incident reports, and licensee event reports. The team organized the data by outage segment and time line. Due to its small sample size, this study produced no conclusive results related to initiating event frequencies, equipment failure rates, or human reliability estimates during shutdown conditions. However, it pointed out the problems of brief or inconsistent recordkeeping. A too brief record results in difficulty determining if the root cause of an event was mechanical or the result of human performance. Retrieval of data can be difficult and labor-intensive. There is a clear need for better, more comprehensive documentation

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

    International Nuclear Information System (INIS)

    St Germain, Shawn Walter; Farris, Ronald Keith; Thomas, Kenneth David

    2015-01-01

    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

  13. Outage management

    International Nuclear Information System (INIS)

    Anonymous

    2006-01-01

    Since constructing Japan's first PWR plant, Mihama Unit 1, MHI has been working to upgrade its technologies. The ongoing goal is to provide PWR nuclear power plants with levels of reliability, safety, economy operation and maintainability unparalleled in the world market. To fulfill its obligations and responsibility as an integrated plant manufacturer in the nuclear industry, MHI keeps a close eye on every facility, component, device and sub-component from the viewpoint of its customers. Backed by its rich experience and advanced technology, MHI continues to enhance the safety, reliability and economy of nuclear plants introducing improvements at every level. MHI continues to develop and improve diagnostic and inspection technologies based on its more than 30 years of experience in inspection and servicing the major and auxiliary facilities within nuclear power plants. MHI secures the integrity of components by developing and deploying technologies to minimize the wear of components and to repair and replace parts either degraded by age or unduly susceptible to wear. MHI backs its development of these technologies with its comprehensive technical capabilities in the design of remote operation equipment and electro mechanics as well as its expertise in basic technologies such as welding and machining. Mitsubishi Heavy Industries, Ltd. is not only a PWR plant constructor, but also offers complete outage support and component services. In partnership with our customers, MHI is helping to reduce outage duration, radiation exposure and costs, by providing its state of the art engineering knowledge, advanced non-destructive examination, inspection, maintenance and repair technologies mentioned above. MHI is performing large equipment refurbishment such as Steam Generator Replacement, Reactor Vessel Head Replacement, LP/HP turbine replacement, and recently completed the first Core Internal Replacement in the world. The following activities are part of the outage

  14. Review of Paks outage results 1990

    International Nuclear Information System (INIS)

    Lukacs, P.; Zsoldos, F.; Kiss, Z.

    1991-01-01

    The year 1990 was not the most successful from an outage point of view at the Paks Nuclear Power Plant in Hungary -there were one or two long delays. Work at unit 4 had a delay of 10 days because of an error made during assembling the reactor vessel. While the outage of unit 3 was running, a feedwater pipe hanger problem was discovered - several hangers were found displaced from the right position. A general inspection of the affected system was required and this took about 11 days. Information about each outage is presented on diagrams, making comparison easier. These diagrams give information about deviations from the outage plan, about work hours performed during outages, and about collective exposure. (author)

  15. Replacement power costs due to nuclear-plant outages: a higher standard of care

    International Nuclear Information System (INIS)

    Gransee, M.F.

    1982-01-01

    This article examines recent state public utility commission cases that deal with the high costs of replacement power that utilities must purchase after a nuclear power plant outage. Although most commissions have approved such expenses, it may be that there is a trend toward splitting the costs of such expenses between ratepayer and stockholder. Commissions are demanding a management prudence test to determine the cause of the outage and whether it meets the reasonable man standard before allowing these costs to be passed along to ratepayers. Unless the standard is applied with flexibility, however, utility companies could invoke the defenses covering traditional common law negligence

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

    International Nuclear Information System (INIS)

    Jacobsson, L.; Svensson, O.

    1991-01-01

    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

  17. Nuclear safety risk control in the outage of CANDU unit

    International Nuclear Information System (INIS)

    Wu Mingliang; Zheng Jianhua

    2014-01-01

    Nuclear fuel remains in the core during the outage of CANDU unit, but there are still nuclear safety risks such as reactor accidental criticality, fuel element failure due to inability to properly remove residual heat. Furthermore, these risks are aggravated by the weakening plant system configuration and multiple cross operations during the outage. This paper analyzes the phases where there are potential nuclear safety risks on the basis of the typical critical path arrangement of the outage of Qinshan NPP 3 and introduces a series of CANDU-specific risk control measures taken during the past plant outages to ensure nuclear safety during the unit outage. (authors)

  18. Advanced Test Reactor outage risk assessment

    International Nuclear Information System (INIS)

    Thatcher, T.A.; Atkinson, S.A.

    1997-01-01

    Beginning in 1997, risk assessment was performed for each Advanced Test Reactor (ATR) outage aiding the coordination of plant configuration and work activities (maintenance, construction projects, etc.) to minimize the risk of reactor fuel damage and to improve defense-in-depth. The risk assessment activities move beyond simply meeting Technical Safety Requirements to increase the awareness of risk sensitive configurations, to focus increased attention on the higher risk activities, and to seek cost-effective design or operational changes that reduce risk. A detailed probabilistic risk assessment (PRA) had been performed to assess the risk of fuel damage during shutdown operations including heavy load handling. This resulted in several design changes to improve safety; however, evaluation of individual outages had not been performed previously and many risk insights were not being utilized in outage planning. The shutdown PRA provided the necessary framework for assessing relative and absolute risk levels and assessing defense-in-depth. Guidelines were written identifying combinations of equipment outages to avoid. Screening criteria were developed for the selection of work activities to receive review. Tabulation of inherent and work-related initiating events and their relative risk level versus plant mode has aided identification of the risk level the scheduled work involves. Preoutage reviews are conducted and post-outage risk assessment is documented to summarize the positive and negative aspects of the outage with regard to risk. The risk for the outage is compared to the risk level that would result from optimal scheduling of the work to be performed and to baseline or average past performance

  19. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Analysis of core damage frequency from internally induced flooding events for Plant Operational State 5 during a refueling outage. Volume 4

    International Nuclear Information System (INIS)

    Dandini, V.; Staple, B.; Kirk, H.; Whitehead, D.; Forester, J.

    1994-07-01

    An estimate of the contribution of internal flooding to the mean core damage frequency at the Grand Gulf Nuclear Station was calculated for Plant Operational State 5 during a refueling outage. Pursuant to this objective, flood zones and sources were identified and flood volumes were calculated. Equipment necessary for the maintenance of plant safety was identified and its vulnerability to flooding was determined. Event trees and fault trees were modified or developed as required, and PRA quantification was performed using the IRRAS code. The mean core damage frequency estimate for GGNS during POS 5 was found to be 2.3 E-8 per year

  20. Outages planning; Planificacion de recargas

    Energy Technology Data Exchange (ETDEWEB)

    Blanquer, N.

    2010-07-01

    The reason of a nuclear power plant outage seems easy. Replace 1/3 of the total core fuel inside reactor for a new, store the old one in a pool and shuffle the rest 2/3 in other positions in the core to optimize fuel burn up. Also is needed to make the preventive, corrective and conservative maintenance, the selected design changes and the regulatory and technical requirements for equipment and systems. To make the plant outage strategy for all the above pack with nuclear safety not challenged is the objective of this article for the Spanish Nuclear Society magazine. (Author)

  1. Outage risk reduction at Diablo Canyon

    International Nuclear Information System (INIS)

    Burnett, Tobias W.T.; Eugene Newman, C.

    2004-01-01

    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)

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

    International Nuclear Information System (INIS)

    Mohammad Hadi Hadavi, S.

    2009-01-01

    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. 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. Lessons learned in planning ALARA/health physics support for major nuclear power plant outages

    International Nuclear Information System (INIS)

    Gilman, T.R.; Lesinski, M.L.

    1987-01-01

    Although as low as reasonably achievable (ALARA)/health physics is viewed as necessary support for nuclear power plant outage work, it can be the last area to which attention is given in preparing for a large-scope outage. Inadequate lead times cause last-minute preparations resulting in delays in planned work. The Dresden Unit 3 Recirculation Piping Replacement Project is examined from a planning viewpoint. The attention that was given the various areas of a comprehensive ALARA/health physics program is examined, and approximate recommended lead times are discussed. The discussion will follow a chronological path from project inception to the beginning stages of outage work. Initially, the scope of work needs to be assessed by individuals familiar with similar projects of equivalent magnitude. Those individuals need to be health physics professionals who understand the particular utility and/or the site's way of doing business. They should also possess a good understanding of preferred industry practices

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

    Energy Technology Data Exchange (ETDEWEB)

    Rosemann, Andreas [Gesellschaft fuer integrierte Systemplanung (GIS) mbH, Weinheim (Germany)

    2014-07-01

    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.)

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

    International Nuclear Information System (INIS)

    Rosemann, Andreas

    2014-01-01

    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.)

  7. Methodology if inspections to carry out the nuclear outages model

    International Nuclear Information System (INIS)

    Aycart, J.; Mortenson, S.; Fourquet, J. M.

    2005-01-01

    Before the nuclear generation industry was deregulated in the United States, refueling and maintenance outages in nuclear power plants usually lasted orotund 100 days. After deregulation took effect, improved capability factors and performances became more important. As a result, it became essential to reduce the critical path time during the outage, which meant that activities that had typically been done in series had to be executed in parallel. The new outage model required the development of new tools and new processes, The 360-degree platform developed by GE Energy has made it possible to execute multiple activities in parallel. Various in-vessel visual inspection (IVVI) equipments can now simultaneously perform inspections on the pressurized reactor vessel (RPV) components. The larger number of inspection equipments in turn results in a larger volume of data, with the risk of increasing the time needed for examining them and postponing the end of the analysis phase, which is critical for the outage. To decrease data analysis times, the IVVI Digitalisation process has been development. With this process, the IVVI data are sent via a high-speed transmission line to a site outside the Plant called Center of Excellence (COE), where a team of Level III experts is in charge of analyzing them. The tools for the different product lines are being developed to interfere with each other as little as possible, thus minimizing the impact of the critical path on plant refueling activities. Methods are also being developed to increase the intervals between inspection. In accordance with the guidelines of the Boiling Water Reactor Vessel and Internals project (BWRVIP), the intervals between inspections are typically longer if ultrasound volumetric inspections are performed than if the scope is limited to IVVI. (Author)

  8. Activities of maintenance and outage

    International Nuclear Information System (INIS)

    Gracia-Orellan, J. M.; Gonzalez, P. L.; Verdu, M. F.; Fernandez, J. A.

    2004-01-01

    Iberinco Nuclear Generation Department have wanted to promote service activities in nuclear power plants for years besides its dedication to engineering activities. for it, in 1997 Nuclear Services Management was created to complement engineering activities and to be able to make an offer for products and turn key services. People involved in this Management have an extensive experience in Services Area, so that all type of maintenance works are promoted, as well other services like dismantling, fallout management and new equipment's for nuclear power plants services. Iberinco's experience in Support Services in Nuclear Power Plants allows to answer effectively to special workers during operation cycle and outages periods. These activities have been made in spanish nuclear power plants and Angra I and II plants, both of them in Brazil. In this area we provide Technical Consulting Management and Supervision to develop the following activities: - Improvement Maintenance Programs based in PSA: Implantation of Maintenance Rule in the plants. - Supervision and Assembly of design modifications in structures, systems and components. - Fulfilment of efficiency tests, inspection and turbo-group modification. - Noise and vibrations analysis. - Valves and rotative equipment calculations and diagnosis tests. Iberinco develop these outage activities itself or as contractors coordinator under its management. A lot of them have been working with Iberinco for many years and have a great experience in the Service Area they are developing. In this article, the main outage activities developed for Iberinco are detailed. (Author)

  9. Integrated outages increase Surry's availability

    International Nuclear Information System (INIS)

    Harms, S.R.; Downs, J.L.

    1995-01-01

    This article describes how, through Virginia Power's and Westinghouse's goal-oriented planning philosophy, teamwork and commitment, average outage duration has decreased significantly. During the past 10 years Virginia Power and its nuclear steam supply system (NSSS) services vendor, Westinghouse Electric Corp., have developed a working partnership with one goal in mind: increasing the availability and capacity factors of the North Anna and Surry nuclear power stations while driving down the operating costs of the plants. The outage integration program, steam generator maintenance agreement (SGMA), and integrated radiological services program form the core of this relationship and helped Virginia Power complete one of the most successful outages in Surry Power Station's operating history

  10. 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

  11. WNP-2 outage safety review methodology

    International Nuclear Information System (INIS)

    Chiang, Albert; Fu, James

    2004-01-01

    A practical and versatile method was developed in the flow chart and checklist forms to show the defense-in-depth for various key safety functions of a nuclear power plant during shutdown. Using four different colors (green, yellow, orange, and red) for indication of levels of defense-in-depth is visually impressive, easy to understand, and was adopted by the outage management personnel as a convenient reference tool for maintenance activity planning before the outage, and schedule changes during the outage. This paper describes the method and its application at Washington Public Power Supply System's Nuclear Project 2 (WNP-2). (author)

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

    International Nuclear Information System (INIS)

    Oubre, R.P.; Shetler, J.

    1985-01-01

    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

  13. Design Concepts for an Outage Control Center Information Dashboard

    International Nuclear Information System (INIS)

    Hugo, Jacques Victor; St Germain, Shawn Walter; Thompson, Cheradan Jo; Whitesides, McKenzie Jo; Farris, Ronald Keith

    2015-01-01

    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

  14. 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

  15. The control of reactor outages

    International Nuclear Information System (INIS)

    Bouget, Y.H.; Berteloot, J.M.

    1995-01-01

    The 1985-1992 period was marked by a continuous decay in French reactors operation. This situation has led the Committee for Outages Mastery to take steps for the improvement of nuclear power plants availability. The control of reactor outages requires an integrated vision of the safety, duration, dosimetry, costs and security aspects and a perfect management of contractors. The paper describes the methodology used for the management and the maintenance of the French PWR reactors stock. A detailed schedule of maintenance tasks with dose estimations is now required from each site to anticipate and optimize the duration of outages. Thanks to this action, a significant reduction of the maintenance costs is observed for the 1992-1995 period. (J.S.). 2 figs

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

    International Nuclear Information System (INIS)

    Sirola, P.; Krajnc, J.; Androjna, F.

    1999-01-01

    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)

  17. Evaluation of potential severe accidents during Low Power and Shutdown Operations at Grand Gulf, Unit 1. Volume 2, Part 1B: Analysis of core damage frequency from internal events for Plant Operational State 5 during a refueling outage, Main report (Section 10)

    International Nuclear Information System (INIS)

    Whitehead, D.; Darby, J.; Yakle, J.

    1994-06-01

    This document contains the accident sequence analysis of internally initiated events for Grand Gulf, Unit 1 as it operates in the Low Power and Shutdown Plant Operational State 5 during a refueling outage. The report documents the methodology used during the analysis, describes the results from the application of the methodology, and compares the results with the results from two full power performed on Grand Gulf. This document, Volume 2, Part 1B, presents chapters Section 10 of this report, Human Reliability Analysis

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

    Energy Technology Data Exchange (ETDEWEB)

    Rosemann, Andreas [Gesellschaft fuer integrierte Systemplanung (GiS) mbH, Weinheim (Germany)

    2014-05-15

    In nuclear power plants it is common to carry out the technical planning of the annual outage work orders in an Enterprise Application Management (EAM) system and to schedule the outage tasks in a project planning tool. The reason for this is historical: Former EAM systems did not (or just to some extend) offer the necessary functionalities to realise the scheduling of the outage; graphical support for the planning was not provided at all. Consequently, scheduling the annual outage was performed in a separate planning tool. Modern Enterprise Application Management (EAM) software builds on established project planning tools with respect to the functionalities and timing of work orders. As a standard they provide editable charts as well as a lot of functionalities which are required for scheduling the annual outage. The functional gap between the demanded planning functionalities and the functionalities provided by the EAM system has been significantly reduced. Depending on the deployed software itself it is possible to extend the EAM system with little effort (in comparison to the promising advantages) so that external project timing planning tools are not required any more. By shifting towards an integrated planning tool, efficiency in planning an outage as well as the quality of communication of the current planning status increases. Furthermore, the basis of information for work orders by the control room staff and therefore safety can be enhanced. (orig.)

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

    International Nuclear Information System (INIS)

    Rosemann, Andreas

    2014-01-01

    In nuclear power plants it is common to carry out the technical planning of the annual outage work orders in an Enterprise Application Management (EAM) system and to schedule the outage tasks in a project planning tool. The reason for this is historical: Former EAM systems did not (or just to some extend) offer the necessary functionalities to realise the scheduling of the outage; graphical support for the planning was not provided at all. Consequently, scheduling the annual outage was performed in a separate planning tool. Modern Enterprise Application Management (EAM) software builds on established project planning tools with respect to the functionalities and timing of work orders. As a standard they provide editable charts as well as a lot of functionalities which are required for scheduling the annual outage. The functional gap between the demanded planning functionalities and the functionalities provided by the EAM system has been significantly reduced. Depending on the deployed software itself it is possible to extend the EAM system with little effort (in comparison to the promising advantages) so that external project timing planning tools are not required any more. By shifting towards an integrated planning tool, efficiency in planning an outage as well as the quality of communication of the current planning status increases. Furthermore, the basis of information for work orders by the control room staff and therefore safety can be enhanced. (orig.)

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

    International Nuclear Information System (INIS)

    Spiler, J.; Basic, I.; Vrbanic, I.; Fifnja, I.; Kastelan, M.; Dagan, W. J.; Shanley, L. B.; Naum, T. J.

    1998-01-01

    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 a utomated b y 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. Qinshan CANDU NPP outage performance improvement through benchmarking

    International Nuclear Information System (INIS)

    Jiang Fuming

    2005-01-01

    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)

  2. On test and maintenance: Optimization of allowed outage time

    International Nuclear Information System (INIS)

    Mavko, B.; Cepin, M.T.

    2000-01-01

    Probabilistic Safety Assessment is widely becoming standard method for assessing, maintaining, assuring and improving the nuclear power plant safety. To achieve one of its many potential benefits, the optimization of allowed outage time specified in technical specifications is investigated. Proposed is the risk comparison approach for evaluation of allowed outage time. The risk of shutting the plant down due to failure of certain equipment is compared to the risk of continued plant operation with the specified equipment down. The core damage frequency serves as a risk measure. (author)

  3. Power Outages

    Science.gov (United States)

    ... Publications Emergency Alerts Preparedness Portal Preparedness Messaging Calendar Social Media Preparedness Toolkits Preparedness News Languages About Us Build a Kit Close Search Enter Search Term(s): Main Content Home Be Informed Power Outages Power Outages Extended power outages may impact ...

  4. Partnership - the heart of integrated outage management

    International Nuclear Information System (INIS)

    Robinson, F.T.

    1995-01-01

    Changes in the power generating industry continue apace. The effects of privatisation are widely visible: nowhere more so than in the growing national and international competition facing the generators around the world. A successful, long-term marriage between generator and contractor on power station outage management offers significant scope for cost reduction, shortening annual plant downtime and generating more megawatts, all within a safety environment of continuous improvement. Working in close partnership, Nuclear Electric and Rolls-Royce Nuclear Engineering Services have remodelled the whole contractor/client strategy. The new discipline, known as integrated outage management and partnering, is already producing shorter outage periods at Bradwell, a Magnox Station in Essex. (author)

  5. Impacts of organization and management on outage performance

    International Nuclear Information System (INIS)

    Huang Yuhao; Cheng, S.-K.

    2004-01-01

    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)

  6. Improving refueling outages through partnership

    International Nuclear Information System (INIS)

    Mercado, Angelo L.

    2004-01-01

    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)

  7. Improvement of availability of PWR nuclear plants through the reduction of the time required for refueling/maintenance outages, Phase 1. Final report

    International Nuclear Information System (INIS)

    Thompson, C.A.

    1978-08-01

    The objective of this project 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 toward reducing its overall duration. Thus, the plant's availability for power production would be increased. Revisions in procedures and some equipment modifications were implemented and evaluated during the Zion Unit 2 refueling/maintenance outage beginning in January 1977. Analysis of the observed data has identified benefits available through improved refueling equipment and also areas where additional new, innovative refueling, or refueling-related equipment should be beneficial. A number of specific design concepts are recommended as a result of Phase 1. In addition, a new master planning mechanism is described for implementation during subsequent planned outages at Zion Station. This final report describes the recommended conceptual designs and planning mechanism and assesses their impact upon future outages. Their effect on savings in refueling time, labor, and radiation exposure is discussed. The estimated economic payoff for these concepts was found to be of such significance that an additional phase of the program is warranted. During this extended phase, a more detailed engineering study should be undertaken to determine the cost of implementation along with more specific estimates of the benefits for PWR plants already in operation or under construction

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

    International Nuclear Information System (INIS)

    Rozman, A.; Androjna, A.

    2010-01-01

    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).

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

    International Nuclear Information System (INIS)

    Miller, D.W.; Green, W.H.

    1995-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D.W.; Green, W.H. [Clinton Power Station Illinois Power Co., IL (United States)

    1995-03-01

    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.

  11. 35/30 outage improvement project

    International Nuclear Information System (INIS)

    Clewett, L.

    2011-01-01

    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

  12. 35/30 outage improvement project

    Energy Technology Data Exchange (ETDEWEB)

    Clewett, L. [Bruce Power, Tiverton, Ontario (Canada)

    2011-07-01

    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

  13. 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

  14. Operational readiness verification, phase 1: A study on safety during outage and restart of nuclear power plants

    International Nuclear Information System (INIS)

    Hollnagel, E.; Gauthereau, V.

    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

  15. 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

  16. Study of Arkansas Nuclear One-1 13th refueling outage

    International Nuclear Information System (INIS)

    Hashiba, Takashi

    1997-01-01

    Recently performance of nuclear power plants in the USA has improved remarkably. Their average automatic shutdown rate has been sharply dropping, although it is still higher than that in Japan, and their average capacity factor has become higher than that in Japan in recent years. One of the main contributors is an extension of the operational period, and another is a shortening of refueling-outage time. It is considerably difficult to have accomplished both the improvement of plant reliability and shortening of refueling-outage time because their refueling outage corresponds to our periodical inspection which is central to maintenance activities in Japanese plants. In order to learn how they have been achieved, a visit to Arkansas Nuclear One-1 (ANO-1) which obtained the top-class result of SALP (Systematic Assessment of Licensee Performance) performed by the Nuclear Regulatory Commission was planned and study of their 13th refueling outage was carried out. Their achievements result from performance-base maintenance and on-line maintenance, based on a proper preventive maintenance program, and untiring efforts of efficiency improvement, represented by the introduction of several on-line systems. And the reason behind this is severe competition concerning power generation cost reduction. (author)

  17. Study of Arkansas Nuclear One-1 13th refueling outage

    Energy Technology Data Exchange (ETDEWEB)

    Hashiba, Takashi [Institute of Nuclear Safety System Inc., Seika, Kyoto (Japan)

    1997-09-01

    Recently performance of nuclear power plants in the USA has improved remarkably. Their average automatic shutdown rate has been sharply dropping, although it is still higher than that in Japan, and their average capacity factor has become higher than that in Japan in recent years. One of the main contributors is an extension of the operational period, and another is a shortening of refueling-outage time. It is considerably difficult to have accomplished both the improvement of plant reliability and shortening of refueling-outage time because their refueling outage corresponds to our periodical inspection which is central to maintenance activities in Japanese plants. In order to learn how they have been achieved, a visit to Arkansas Nuclear One-1 (ANO-1) which obtained the top-class result of SALP (Systematic Assessment of Licensee Performance) performed by the Nuclear Regulatory Commission was planned and study of their 13th refueling outage was carried out. Their achievements result from performance-base maintenance and on-line maintenance, based on a proper preventive maintenance program, and untiring efforts of efficiency improvement, represented by the introduction of several on-line systems. And the reason behind this is severe competition concerning power generation cost reduction. (author)

  18. Outage time reduction in GKN II without loss of safety

    International Nuclear Information System (INIS)

    Sturm, J.

    1999-01-01

    GKN II is a 1340 MWE 4-loop pressurised water reactor from Siemens KONVOI type, located in the south of Germany. It was originally connected to the grid at the end of 1988. Commercial operation under utility responsibility started at the second half of 1989. The first outage was performed in 1990. Beginning from this date, the outage duration was contiguously reduced from 33 days to 15 days in 1996. In 1998, two refueling and maintenance outages were performed, each with a duration of 7 days. Key planning factors to achieve these results are: A well adapted planning organisation with an outage manager and an outage planning team. An effective long term planning. This means the combination of work with a long duration every 4 or 8 years. No longlasting work in the years in between. Main work only on one safety train per year. Optimisation and standardisation of the shutdown and the startup sequence. The real change of reactor states have been modified, compared to the vendor recommendations. An tests are assigned to plant conditions, where they are most effective and are less time critical. Small modifications in the plant, mainly on the auxiliary systems, to speedup some sequences. Extreme detailed planning of maintenance and periodic tests. Each work/test can be found in a detailed schedule with a dedicated time widow. Optimized tools to perform the detailed planning and to implement the feedback of experience from former outages. Optimized tools for maintenance and handlings of heavy equipment on the critical path. Optimized tools to perform periodic tests. Key factors during outage are: Permanent control of the schedules with an updated 3-day program. Best and permanent information with this 3-day program of all people that are involved. Fast reaction on delays. Outage managers permanent on site. Gain in safety during shutdown states, with reduced outage duration: It has to be proven, that short outages don't lead to faster and less accurate work. It can be

  19. Analysis of T101 outage radiation dose

    International Nuclear Information System (INIS)

    Li, Zhonghua

    2008-01-01

    Full text: Collective radiation dose during outage is about 80% of annual collective radiation dose at nuclear power plants (NPPs). T 101 Outage is the first four-year outage of Unit 1 at Tianwan Nuclear Power Station (TNPS) and thorough overhaul was undergone for the 105-day's duration. Therefore, T 101 Outage has significant reference meaning to reducing collective radiation dose at TNPS. This paper collects the radiation dose statistics during T 101 Outage and analyses the radiation dose distribution according to tasks, work kinds and varying trend of the collective radiation dose etc., comparing with other similar PWRs in the world. Based on the analysis this paper attempts to find out the major factors in collective radiation dose during T 101 Outage. The major positive factor is low radiation level at workplace, which profits from low content of Co in reactor construction materials, optimised high-temperature p H value of the primary circuit coolant within the tight range and reactor operation without trips within the first fuel cycle. One of the most negative factors is long outage duration and many person-hours spent in the radiological controlled zone, caused by too many tasks and inefficient work. So besides keeping good performance of reducing radioactive sources, it should be focused on how to improve implementation of work management including work selection, planning and scheduling, work preparation, work implementation, work assessment and feedback, which can lead to reduced numbers of workers needed to perform a task, of person-hours spent in the radiological controlled zone. Moreover, this leads to reduce occupational exposures in an ALARA fashion. (author)

  20. 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.

  1. The status of the Hanaro class 4 power outage

    International Nuclear Information System (INIS)

    Hyungkyoo, K.; Hoansung, J.; Jongsup, W.

    2004-01-01

    Electric power is essential for all industrial plant. All who use electric power desire a perfect frequency, voltage stability, and reliability all the time. But this cannot be realized in practice because of the many causes of a power supply disturbance that are beyond the control of the utility. Since the first criticality of the Hanaro research reactor, the major reasons for reactor trips were system malfunctions and inexperienced operators in the initial stage of its operation. As Hanaro is stabilizing, the power supply outage becomes the major reason for a reactor trip. This paper describes the status of power supply outages. This paper deals with not only the outages which have an effect on Hanaro operation but also the reasons for the Hanaro class-4 power outages. The class-4 power is a commercial power which supplies the load centers and the large motors such as primary cooling pumps and secondary cooling pumps. Even if a class-4 power outage occurs, Hanaro is safe because of the reactor cooling by natural convection and the flywheel effect of the primary cooling pumps. The analysis of the characteristics and the trends of the outages can provide clues to how the outages can be minimized and what the impact of the outages are on the operation. For the site-wide class-4 power, the latest failure rate has been 2.36 per year and the mean time to repair is 23,78 minutes for the exponentially weighted mowing average. The unavailability of the Class-4 power is 1.5 10 -4

  2. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1. Analysis of core damage frequency from internal events for plant operational state 5 during a refueling outage. Internal events appendices K to M

    International Nuclear Information System (INIS)

    Forester, J.; Yakle, J.; Walsh, B.; Darby, J.; Whitehead, D.; Staple, B.; Brown, T.

    1994-07-01

    This report provides supporting documentation for various tasks associated with the performance of the probabilistic risk assessment for Plant Operational State 5 (approximately Cold Shutdown as defined by Grand Gulf Technical Specifications) during a refueling outage at Grand Gulf, Unit 1 as documented in Volume 2, Part 1 of NUREG/CR-6143. The report contains the following appendices: K - HEP Locator Files; L - Supporting Information for the Plant Damage State Analysis; M - Summary of Results from the Coarse Screening Analysis - Phase 1A

  3. Key issues for the control of refueling outage duration and costs in PWR nuclear power plants

    International Nuclear Information System (INIS)

    Degrave, C.; Martin-Onraet, M.

    2000-01-01

    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)

  4. Excellence through outage planning and scheduling

    International Nuclear Information System (INIS)

    Ferriole, G.

    1987-01-01

    The Nuclear and Fossil Generation Division of Electricite de France (EdF) has been the largest nuclear plant operating utility in France since 1984. The size of the units, their standardization, and extensive operating experience were favorable parameters leading to the development of a very complete maintenance organization. Electricite de France believes in the importance of well-defined maintenance concepts. These maintenance concepts contribute to outage performance by requiring a careful consideration of work to be done and by defining the techniques and means of accomplishing this work. In addition to maintenance concepts and careful planning and scheduling, good outage management is achieved through the motivation and dedication of the people involved. It is the key to good operational results

  5. The course of a true outage never ran so smooth

    International Nuclear Information System (INIS)

    Harberts, Craig

    1994-01-01

    In order to improve the performance of outages at San Onofre Nuclear Generating Station in California, the working structure of the entire organisation has had to be radically altered, in order to bring San Onofre up to standard with other nuclear plants known to be performing well. Working systems were simplified and efficiency improved. Personnel needed to be remotivated to work cooperatively and the outage budget process was revised to include input from all relevant organizations, historical costs and benchmark information from other plants that performed well. Finally, the decision making and teamwork culture has altered radically at San Onofre over the last decade. (UK)

  6. Cycle 7 outage experience

    International Nuclear Information System (INIS)

    Gadeken, A.D.

    1986-03-01

    The scheduled 58-day refueling outage in preparation for the seventh operating cycle of the Fast Flux Test Facility (FFTF) was successfully completed three days ahead of schedule. The planning and execution of the outage was greatly aided by Project/2 automated scheduling capabilities. For example, the use of ''maintenance windows'' and resource loading capabilities was particularly effective. The value of the planning process was demonstrated by the smooth transition into the outage phase after an early shutdown and set the stage for our best outage to date

  7. Optimization of safety equipment outages improves safety

    International Nuclear Information System (INIS)

    Cepin, Marko

    2002-01-01

    Testing and maintenance activities of safety equipment in nuclear power plants are an important potential for risk and cost reduction. An optimization method is presented based on the simulated annealing algorithm. The method determines the optimal schedule of safety equipment outages due to testing and maintenance based on minimization of selected risk measure. The mean value of the selected time dependent risk measure represents the objective function of the optimization. The time dependent function of the selected risk measure is obtained from probabilistic safety assessment, i.e. the fault tree analysis at the system level and the fault tree/event tree analysis at the plant level, both extended with inclusion of time requirements. Results of several examples showed that it is possible to reduce risk by application of the proposed method. Because of large uncertainties in the probabilistic safety assessment, the most important result of the method may not be a selection of the most suitable schedule of safety equipment outages among those, which results in similarly low risk. But, it may be a prevention of such schedules of safety equipment outages, which result in high risk. Such finding increases the importance of evaluation speed versus the requirement of getting always the global optimum no matter if it is only slightly better that certain local one

  8. Extended layup of steam generators during a refurbishment outage

    International Nuclear Information System (INIS)

    Marks, C.R.; Little, M.D.; Slade, J.; Gendron, T.

    2009-01-01

    In May 2008, Point Lepreau Generating Station (PLGS), owned and operated by New Brunswick Power Nuclear (NBPN), entered an extended refurbishment outage initially expected to last approximately 18 months. NBPN had the two inter-related goals with respect to layup of the steam generators during this period: equipment preservation and inspection interval modification. The steam generators were to be preserved such that there was no loss of operating life due to corrosion of either the tubing (Alloy 800NG) or other internal components (with carbon steel being the limiting material with respect to corrosion). Additionally, NBPN desired that the time in layup not count as operating time in setting the schedule for future inspections. That is, a key goal of the steam generator layup is that the future inspection interval be based on operating time, not calendar time. The NBPN approach consists of the following four steps: A review of industry operating experience with long outages (including both PWRs and PHWRs); The development of technically based layup strategies and procedures; A mid-outage review of the implementation of the layup strategies and procedures; and A post-outage review to determine if the actual conditions in the steam generators will support modification of the inspection interval. This paper discusses the results of the first three of these steps. At this time, the plant is still in the refurbishment outage. Throughout the outage evaluation process, the following issues have been the main focus of the reviews: The potential for degradation (pitting and cracking) of steam generator tubes; The potential for general corrosion of carbon and low alloy steel internals; Oxidation of deposits (which could subsequently lead to oxidizing conditions during operation, possibly leading to tube degradation). This paper discusses the industry operating experience reviewed, the pre-outage assessments, and the mid-outage assessments. Current outage planning places the

  9. Darlington Station outage - a maintenance perspective

    International Nuclear Information System (INIS)

    Plourde, J.; Marczak, J.; Stone, M.; Myers, R.; Sutton, K.

    1997-01-01

    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)

  10. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Evaluation of severe accident risks for plant operational state 5 during a refueling outage. Main report and appendices, Volume 6, Part 1

    International Nuclear Information System (INIS)

    Brown, T.D.; Kmetyk, L.N.; Whitehead, D.; Miller, L.; Forester, J.; Johnson, J.

    1995-03-01

    Traditionally, probabilistic risk assessments (PRAS) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Recent studies and operational experience have, however, implied that accidents during low power and shutdown could be significant contributors to risk. In response to this concern, in 1989 the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The program consists of two parallel projects being performed by Brookhaven National Laboratory (Surry) and Sandia National Laboratories (Grand Gulf). The program objectives include assessing the risks of severe accidents initiated during plant operational states other than full power operation and comparing the estimated risks with the risk associated with accidents initiated during full power operation as assessed in NUREG-1150. The scope of the program is that of a Level-3 PRA. The subject of this report is the PRA of the Grand Gulf Nuclear Station, Unit 1. The Grand Gulf plant utilizes a 3833 MWt BUR-6 boiling water reactor housed in a Mark III containment. The Grand Gulf plant is located near Port Gibson, Mississippi. The regime of shutdown analyzed in this study was plant operational state (POS) 5 during a refueling outage, which is approximately Cold Shutdown as defined by Grand Gulf Technical Specifications. The entire PRA of POS 5 is documented in a multi-volume NUREG report (NUREG/CR-6143). The internal events accident sequence analysis (Level 1) is documented in Volume 2. The Level 1 internal fire and internal flood analyses are documented in Vols 3 and 4, respectively

  11. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Evaluation of severe accident risks for plant operational state 5 during a refueling outage. Main report and appendices, Volume 6, Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.D.; Kmetyk, L.N.; Whitehead, D.; Miller, L. [Sandia National Labs., Albuquerque, NM (United States); Forester, J. [Science Applications International Corp., Albuquerque, NM (United States); Johnson, J. [GRAM, Inc., Albuquerque, NM (United States)

    1995-03-01

    Traditionally, probabilistic risk assessments (PRAS) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Recent studies and operational experience have, however, implied that accidents during low power and shutdown could be significant contributors to risk. In response to this concern, in 1989 the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The program consists of two parallel projects being performed by Brookhaven National Laboratory (Surry) and Sandia National Laboratories (Grand Gulf). The program objectives include assessing the risks of severe accidents initiated during plant operational states other than full power operation and comparing the estimated risks with the risk associated with accidents initiated during full power operation as assessed in NUREG-1150. The scope of the program is that of a Level-3 PRA. The subject of this report is the PRA of the Grand Gulf Nuclear Station, Unit 1. The Grand Gulf plant utilizes a 3833 MWt BUR-6 boiling water reactor housed in a Mark III containment. The Grand Gulf plant is located near Port Gibson, Mississippi. The regime of shutdown analyzed in this study was plant operational state (POS) 5 during a refueling outage, which is approximately Cold Shutdown as defined by Grand Gulf Technical Specifications. The entire PRA of POS 5 is documented in a multi-volume NUREG report (NUREG/CR-6143). The internal events accident sequence analysis (Level 1) is documented in Volume 2. The Level 1 internal fire and internal flood analyses are documented in Vols 3 and 4, respectively.

  12. Management of planned unit outages

    International Nuclear Information System (INIS)

    Brune, W.

    1984-01-01

    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)

  13. Evaluation of allowed outage time using PRA results

    International Nuclear Information System (INIS)

    Johanson, G.

    1985-01-01

    In a probabilistic risk assessment (PRA) different measures of risk importance can be established. These measures can be used as a basis for further evaluation and determination of allowed outage time for specific components, within safety systems of a nuclear power plant. In order to optimize the allowed outage time (AOT) stipulated in the plant's Technical Specification it is necessary to create a methodology which could incorporate existing PRA data into a quantitative extrapolation. In order to evaluate the plant risk status due to AOT in a quantitative manner, the risk achievement worth is utilized. Risk achievement worth is defined as follows: to measure the worth of a feature, in achieving the present risk, one approach is to remove the feature and then determine how much the risk has increased. Thus, the risk achievement worth is formally defined to be the increase in risk if the feature were assumed not be there or to be failed. Another parameter of interest for this analysis is the shutdown risk increase. The shutdown risk achievement worth must be incorporated into the accident sequence risk achievement worth to arrive at an optimal set of plant specific AOTs

  14. Key Issues for the control of refueling outage duration and costs in PWR Nuclear Power Plants

    International Nuclear Information System (INIS)

    Degrave, Claude

    2002-01-01

    For several years, EDF, within the framework of the CIDEM1 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 of the 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)

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

    International Nuclear Information System (INIS)

    Farago, P.; Hamvas, I.; Szecsenyi, Zs.; Nemes, I.; Javor, E.

    2000-01-01

    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

  16. Methodology if inspections to carry out the nuclear outages model; Metodologia de inspeccciones para cumplir el modelo de paradas nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Aycart, J.; Mortenson, S.; Fourquet, J. M.

    2005-07-01

    Before the nuclear generation industry was deregulated in the United States, refueling and maintenance outages in nuclear power plants usually lasted orotund 100 days. After deregulation took effect, improved capability factors and performances became more important. As a result, it became essential to reduce the critical path time during the outage, which meant that activities that had typically been done in series had to be executed in parallel. The new outage model required the development of new tools and new processes, The 360-degree platform developed by GE Energy has made it possible to execute multiple activities in parallel. Various in-vessel visual inspection (IVVI) equipments can now simultaneously perform inspections on the pressurized reactor vessel (RPV) components. The larger number of inspection equipments in turn results in a larger volume of data, with the risk of increasing the time needed for examining them and postponing the end of the analysis phase, which is critical for the outage. To decrease data analysis times, the IVVI Digitalisation process has been development. With this process, the IVVI data are sent via a high-speed transmission line to a site outside the Plant called Center of Excellence (COE), where a team of Level III experts is in charge of analyzing them. The tools for the different product lines are being developed to interfere with each other as little as possible, thus minimizing the impact of the critical path on plant refueling activities. Methods are also being developed to increase the intervals between inspection. In accordance with the guidelines of the Boiling Water Reactor Vessel and Internals project (BWRVIP), the intervals between inspections are typically longer if ultrasound volumetric inspections are performed than if the scope is limited to IVVI. (Author)

  17. Outage management philosophies at Oconee nuclear station

    International Nuclear Information System (INIS)

    Bond, R.T.

    1991-01-01

    At Oconee the biggest single factor in improving availability and cutting cost per kilowatt-hour is reducing outage lengths. This must be accomplished without compromising the quality of the work that must be performed during these outages. Oconee has completed 35 refueling outages and has gained considerable experience in outage management. Since 1984, outage costs and durations have consistently been reduced while continuing to improve capacity factors. The last 6 refueling outages were 43, 42, 45, 42, 41, and 44 days, respectively. The capacity factors for these units between refueling outages are 98, 94, 96, 98, and 98%, respectively. The average cost of outages has been less than $12 million. It is believed that success cannot be attributed to any one factor by itself but is a compilation of many factors, all complementing each other. It is also believed, however, that there are four key areas that represent philosophies and can be given most of the credit for successful outages: planning, experience, teamwork, and outage management

  18. Management techniques that keep outages on schedule

    International Nuclear Information System (INIS)

    Taylor, R.B.

    1987-01-01

    During the immature operation of the Pickering Units 5 through 8, significant numbers of outages have been required to deal with warranty inspections and equipment problems. Techniques have been developed to ensure that outages are properly planned and managed so that outage time is minimized, overtime is minimized, and capacity factor is maximized, while ensuring that personnel safety is not compromised. Successful outage planning and execution requires the commitment of many on-station and off-station resources groups. Coordination of all of these groups is required both before and during the outage to ensure outage time is not lost due to unavailability of men or equipment at the time they are required. This paper details the control processes that must be used prior to, during, and after an outage to ensure that time is not lost unnecessarily during outages. Successful outage management at Pickering Nuclear Generating Station can be subdivided into three stages; preoutage planning, outage execution, and postoutage review

  19. Shortened outage duration and increased safety with head assembly upgrade packages

    International Nuclear Information System (INIS)

    Leanne, M.; Lisien, P.E.; Plute, K.; Duran, J.

    2007-01-01

    To significantly reduce outage critical path duration and personnel radiation exposure, and to increase personnel safety, Westinghouse Electric Co., LLC has designed and installed upgrades to the existing head assemblies of operating pressurized water reactors. These upgrades are known as Head Assembly Upgrade Packages (HAUPs) or Simplified Head Assemblies (SHAs). Custom configurations are created from a set of standard elements to optimize the design for each unique containment, head assembly configuration, and licensing basis. Two primary options are available for implementation: a full HAUP or targeted component and system upgrades. Plants may achieve much of the outage savings, dose reduction, and safety improvements even with a more limited hardware scope. A range of improvements can be offered from integral missile shields, to redesigned duct work, radiation shields, and cable layout and connection optimization. The hardware changes are customized to target the scope that adds the most value for a given plant. While combining upgrades with a reactor vessel head (RVH) replacement adds some flexibility, it is not necessary. Some plants have chosen to implement targeted upgrades prior to a replacement RVH outage and then complete the remainder of the full HAUP during the replacement RVH outage. Three-dimensional computer aided design tools are used in the conceptual and detailed design phases to identify and avoid interferences between existing and replacement plant components. State-of-the-art computational fluid dynamics models for control drive mechanism (CDM) cooling systems are used to demonstrate the ability to maintain or improve the original design performance while greatly simplifying the disassembly/re-assembly activities. Likewise, state-of-the-art finite element analysis methods allow optimization of structural components while meeting code limits for design basis accident conditions. (authors)

  20. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1. Volume 5: Analysis of core damage frequency from seismic events for plant operational state 5 during a refueling outage

    International Nuclear Information System (INIS)

    Budnitz, R.J.; Davis, P.R.; Ravindra, M.K.; Tong, W.H.

    1994-08-01

    In 1989 the US Nuclear Regulatory Commission (NRC) initiated an extensive program to examine carefully the potential risks during low-power and shutdown operations. The program included two parallel projects, one at Sandia National Laboratories studying a boiling water reactor (Grand Gulf), and the other at Brookhaven National Laboratory studying a pressurized water reactor (Surry Unit 1). Both the Sandia and Brookhaven projects have examined only accidents initiated by internal plant faults---so-called ''internal initiators.'' This project, which has explored the likelihood of seismic-initiated core damage accidents during refueling outage conditions, is complementary to the internal-initiator analyses at Brookhaven and Sandia. This report covers the seismic analysis at Grand Gulf. All of the many systems modeling assumptions, component non-seismic failure rates, and human effort rates that were used in the internal-initiator study at Grand Gulf have been adopted here, so that the results of the study can be as comparable as possible. Both the Sandia study and this study examine only one shutdown plant operating state (POS) at Grand Gulf, namely POS 5 representing cold shutdown during a refueling outage. This analysis has been limited to work analogous to a level-1 seismic PRA, in which estimates have been developed for the core-damage frequency from seismic events during POS 5. The results of the analysis are that the core-damage frequency for earthquake-initiated accidents during refueling outages in POS 5 is found to be quite low in absolute terms, less than 10 -7 /year

  1. Integrated outage management: Leveraging utility system assets including GIS and AMR for optimum outage response

    Energy Technology Data Exchange (ETDEWEB)

    Finamore, E. P.

    2004-02-01

    The control of electrical system outages is discussed. The principal argument advanced is that traditional stand-alone methods of outage response will no longer get the job done without utility companies integrating their outage management systems with other system assets such as GIS (geographic information system) and AMR (advanced metering systems). Many meter reading systems, while primarily supporting customer billing, can also provide outage alarm and some are also capable of service restoration notification, which is an invaluable benefit to service operators since it obviates the need for verifying system restoration by labour-intensive on-site visits or customer call-backs. If successfully leveraged, optimization of all utility assets and improvements in labour productivity can results in improved outage management performance gains without affecting performance in other areas.

  2. Improving nuclear utility generation capacity, understanding the sources of forced outage and learning how to prevent them

    International Nuclear Information System (INIS)

    Brodeur, D.L.; Todreas, N.E.; Angus, V.T.

    1998-01-01

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Remphal, M. [Ontario Power Generation, Darlington, Ontario (Canada)

    2011-07-01

    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)

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

    International Nuclear Information System (INIS)

    Remphal, M.

    2011-01-01

    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)

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

    International Nuclear Information System (INIS)

    Naydenov, N.; Mignone, O.

    2004-01-01

    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

  6. Outage scheduling and implementation

    International Nuclear Information System (INIS)

    Allison, J.E.; Segall, P.; Smith, R.R.

    1986-01-01

    Successful preparation and implementation of an outage schedule and completion of scheduled and emergent work within an identified critical path time frame is a result of careful coordination by Operations, Work Control, Maintenance, Engineering, Planning and Administration and others. At the Fast Flux Test Facility (FFTF) careful planning has been responsible for meeting all scheduled outage critical paths

  7. Areva: experiences in outage services

    International Nuclear Information System (INIS)

    Wiemeier, R.; Mueller, N.; Blanco, I. J.

    2010-01-01

    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)

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

    International Nuclear Information System (INIS)

    Parfouru, S.; De-Beler, N.

    2012-01-01

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    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

  10. 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)

    1998-12-31

    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)

  11. 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)

  12. A Study on the Frequency of Initiating Event of OPR-1000 during Outage Periods

    Energy Technology Data Exchange (ETDEWEB)

    Hong Jae Beol; Jae, Moo Sung [Hanyang Univ., Seoul (Korea, Republic of)

    2013-10-15

    These sources of data did not reflect the latest event data which have occurred during the PWR outage to the frequencies of initiating event Electric Power Research Institute(EPRI) in USA collected the data of loss of decay heat removal during outage from 1989 to 2009 and published technical report. Domestic operating experiences for LOOP is gathered in Operational Performance Information System for Nuclear Power Plant(OPIS). To reduce conservatism and obtain completeness for LPSD PSA, those data should be collected and used to update the frequencies. The frequencies of LOSDC and LOOP are reevaluated using the data of EPRI and OPIS in this paper. Quantification is conducted to recalculate core damage frequency(CDF), since the rate is changed. The results are discussed below. To make an accurate estimate of the initiating events of LPSD PSA, the event data were collected and the frequencies of initiating events were updated using Bayesian approach. CDF was evaluated through quantification. Δ CDF is -40% and the dominant contributor is pressurizer PSV stuck open event. The most of the event data in EPRI TR were collected from US nuclear power plant industry. Those data are not enough to evaluate outage risk precisely. Therefore, to reduce conservatism and obtain completeness for LPSD PSA, the licensee event report and domestic data should be collected and reflected to the frequencies of the initiating events during outage.

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

    International Nuclear Information System (INIS)

    2006-01-01

    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

  14. Outage Risk Assessment and Management (ORAM) technology to improve outage safety and economics

    International Nuclear Information System (INIS)

    Kalra, S.P.

    2004-01-01

    The Electric Power Research Institute (EPRI) has undertaken an aggressive program, called ORAM (Outage Risk Assessment and Management), to provide utilities with tools and technology to assist in managing risk during the planning and conduct of outages. The ORAM program consists of the following 6 steps: i) Perform utility surveys and visits on shutdown risk management needs, ii) Perform probabilistic shutdown safety assessments (PSSAs) to identify generic insights that can be incorporated into risk management guidelines and identify selected areas for the development of contingency actions, iii) Develop risk management guidelines (RMG's) that provide a systematic approach to the planning and conduct of outages from a safety perspective. Incorporate insights from the shutdown safety assessments and other operating experience into the RMG's. iv) Develop selected contingency actions including a thermalhydraulic tool kit to address higher risk time periods and activities identified in the shutdown safety assessments, v) Develop computer software that integrates all of the above capability into an easy to use tool for effective shutdown operation management for utilities, vi) Provide assistance in the transfer of this technology and the application of these tools. This paper briefly describes the technical approach and tools developed under EPRI's ORAM program and its applications for improving outage safety and economics. (author)

  15. Primary Water Chemistry Control during a Planned Outage at Bruce Power

    International Nuclear Information System (INIS)

    Ma, Guoping; Nashiem, Rod; Matheson, Shane; Yabar, Berman; Harper, Bill; Roberts, John G.

    2012-09-01

    Bruce Power has developed a comprehensive outage water chemistry program, which includes both primary and secondary chemistry requirements during planned outages. The purpose of the program is to emphasize the chemistry requirements during outages and subsequent start-ups in order to maintain the integrity of the systems, minimise activity transport and radiation fields, reduce the Carbon-14 release, and to ensure that the requirements are integrated with the outage management program. Prior to a planned outage, Station Chemical Technical Sections identify outage chemistry requirements to Operations and Outage Planning and ensure that work necessary to correct system chemistry issues is within outage work scope. The outage water chemistry program provides direction for establishing alternative sampling locations as demanded by the system configuration during the outage and identifies outage prerequisites for nuclear system purification capabilities. These requirements are contained in an outage checklist. The paper mainly highlights the primary water chemistry issues and chemistry control strategies during planned outages and discusses challenges and successes. (authors)

  16. Reactor refurbishment in an outage environment

    International Nuclear Information System (INIS)

    Gowthorpe, P.; Hoare, R.

    2012-01-01

    Reactor life extension has typically been performed during specific refurbishment outages. These outages are long and costly due to the sheer complexity of the scope, not to mention the ever present discovery work. A scope of this size requires a huge labour force to execute, which poses significant challenges. The work is difficult to staff with qualified people able to execute the work smoothly and managing the required labour pool problematic. Cost and time overruns are inevitable in that environment. Reducing the cost and schedule is critical to the long term viability of reactor refurbishment projects. With planning, the total cost of the refurbishment can be reduced by managing the inspection and repairs during normal outages. Identifying what activities need to be done each outage for the life of the reactor and bringing the latest technology can make this viable. Tightly planned outages with a small well trained labour force will go a long way to reducing costs. The suite of services and tooling available to the utilities to manage their reactor integrity has improved significantly in recent years and continues to evolve. New feeder inspection technologies can provide improved inspection results for the complex feeder geometry. These improvements lead to more accurate wear rates and better predictions of component life. Feeders that need replacement based on improved inspection techniques can be replaced systematically during regular outages rather than specific refurbishment outages. Targeting areas rather than entire feeders reduces time, dose and cost. In cases where feeder replacement isn't feasible or where unpredicted wear is found, a feeder weld overlay process can be used. To manage the reactor work, new data systems are under development that allow for effective tracking of each activity performed and outcomes in a single package. (author)

  17. Outage costs: who should pay?

    International Nuclear Information System (INIS)

    Stivison, D.V.

    1986-01-01

    Decisions affecting the Three Mile Island-1 and -2 reactors illustrate new an stricter standards which apply to how regulator will allocate the costs of outages. The rule allows outages for normal refueling and other normal shutdowns if return to the power grid is assured. TMI-1 was removed from the rate base one year after the accident, and was readmitted only after achieving full power in 1986. A reasonableness standard based on an analysis of the outage and utility responses is the basis for deciding for or against removal. The author cites cases in which unreasonable actions caused the Nuclear Regulatory Commission to charge utility management with imprudence. New safety standards will force utilities to reduce employee error, equipment failure, and management weakness. 19 references

  18. Bingham Pump Outage Pits: Environmental information document

    International Nuclear Information System (INIS)

    Pekkala, R.O.; Jewell, C.E.; Holmes, W.G.; Marine, I.W.

    1987-03-01

    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 137 Cs and 90 Sr) 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. Use of workstations in the ANAV outage tasks course access

    International Nuclear Information System (INIS)

    Gómez Rodriguez, Carlos A.

    2016-01-01

    The access course for the Asco and Vandellos II Nuclear Power Plants contains all of the training that is considered necessary in compliance with the stipulations of current legislation for the pupils to carry out their activity at the plants. Given the heterogeneity of the special characteristics of those workers who take part in the outage tasks at our plants we have sought to improve the learning values of their access course with the inclusion of Work Stations since 2013. Several changes have been made in the training action since that date to make it more interactive.

  20. Siemens capabilities to perform detailed fuel inspections during short outages

    International Nuclear Information System (INIS)

    Knecht, K.; Reparaz, A.

    1999-01-01

    Fuel inspection data are used to support development activities such as corrosion resistant cladding and advanced fuel assembly designs that will reach higher burnups. Increased inspection efforts are necessary to optimize fuel management and performance strategies. Additionally, there is an increasing trend to reduce outage time in Germany and abroad. Siemens has recently developed several timesaving systems for rapid inspection of fuel assemblies and core components. Siemens' focus in developing these systems has been to obtain data in reduced reactor outage time while increasing both the volume and the quality of the measured data. Mast sipping for PWRs is used for identifying leaking fuel assemblies and allows early detection of leaks during downloading of the fuel assemblies from the reactor. An In-Core sipping system for BWRs based on a hood technique to allow testing a full core within 16 hours is under development. (authors)

  1. Thermal Hydraulic Assessment for Loss of SDCS Event During the Outage of CANDU Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jonghyun [Gnest, Inc. Taejon (Korea, Republic of); Lee, Kwangho; Oh, Haechol; Jun, Hwangyong [KEPRI, Taejon (Korea, Republic of)

    2006-07-01

    During the outage(overhaul) of the nuclear power plant, there are several operating states other than the full power state, that is 'Hot-Zero Power', 'Depressurized-Cooldown', and 'Partially Drained'. Until now safety assessment has not been done much for this operating state of CANDU type reactor worldwide. For the accuracy and confidence of PSA for the CANDU outage, the safety analysis is necessary. At the first stage, we analyzed the thermal hydraulic characteristics and safety of the postulated event of loss of shutdown cooling system (SDCS) during the partially drained state which is the longest one in the middle of outage period. As an analysis tool, this study uses the best estimate thermal hydraulic code, RELAP5/CANDU which was modified according to the CANDU specific characteristics and based on RELAP5.Mod3.

  2. 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.

  3. Predicting Power Outages Using Multi-Model Ensemble Forecasts

    Science.gov (United States)

    Cerrai, D.; Anagnostou, E. N.; Yang, J.; Astitha, M.

    2017-12-01

    Power outages affect every year millions of people in the United States, affecting the economy and conditioning the everyday life. An Outage Prediction Model (OPM) has been developed at the University of Connecticut for helping utilities to quickly restore outages and to limit their adverse consequences on the population. The OPM, operational since 2015, combines several non-parametric machine learning (ML) models that use historical weather storm simulations and high-resolution weather forecasts, satellite remote sensing data, and infrastructure and land cover data to predict the number and spatial distribution of power outages. A new methodology, developed for improving the outage model performances by combining weather- and soil-related variables using three different weather models (WRF 3.7, WRF 3.8 and RAMS/ICLAMS), will be presented in this study. First, we will present a performance evaluation of each model variable, by comparing historical weather analyses with station data or reanalysis over the entire storm data set. Hence, each variable of the new outage model version is extracted from the best performing weather model for that variable, and sensitivity tests are performed for investigating the most efficient variable combination for outage prediction purposes. Despite that the final variables combination is extracted from different weather models, this ensemble based on multi-weather forcing and multi-statistical model power outage prediction outperforms the currently operational OPM version that is based on a single weather forcing variable (WRF 3.7), because each model component is the closest to the actual atmospheric state.

  4. Maintenance of nuclear power plants

    International Nuclear Information System (INIS)

    Lashgari, Farbod.

    1995-01-01

    This paper is about maintenance of nuclear power plants. In part one, the outage management of nuclear power plants has described. Meaning of the outage and objectives of outage management is given in introduction. The necessity of a long-term outage strategy is shown in chapter one. The main parts of an outage are as follows: Planning; Preparation; Execution, Each of them and also post-outage review have been explained in the followed chapters. Part two deals with technical details of main primary components of nuclear power plant type WWER. After an introduction about WWER reactors, in each chapter first the general and detailed description of main primary components has given and then their maintenance schedules and procedures. Chapter about reactor and steam generator is related to both types of WWER-440 and WWER-1000, but chapter about reactor coolant pump has specified to WWER-1000 to be more in details.(author)

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

    International Nuclear Information System (INIS)

    Oliveira, Magno Jose de; Amaral, Marcos Antonio do; Minelli, Edson; Ferreira, William Alves

    2009-01-01

    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. Optimal utilization of outages. The tasks of the OEM and/or service provider

    International Nuclear Information System (INIS)

    Jakobs, Norbert; Grauf, Eberhard

    1998-01-01

    The deregulation of Europe's power market on January 1, 1999 will force many electric utilities and especially nuclear power plant operators to introduce extensive cost-cutting measures in order that they can hold their own in the new competitive environment. Existing plants basically have three potential ways of reducing their power generating costs: by increasing availability, reducing fuel costs and cutting back operating costs. Optimizing plant outages provides considerable potential for raising plant availability but can also lower operating costs by reducing expenditure on maintenance. In order to optimize an outage in terms of performance time and cost, there are a number of starting points based on certain key factors: organization, planning, logistics, performance monitoring, plant and equipment enhancements as well as personnel motivation. To reach this goal it is necessary for the original equipment manufacturer (OEM) and/or service provider to be involved in these activities to a much greater extent than before and for a closer form of partnership to be established with the consumer. For it is only within a team having a common set of goals that the successes of the past have been able to be achieved and new tasks can be efficiently handled in the future. (author)

  7. 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)

  8. Residential outage cost estimation: Hong Kong

    International Nuclear Information System (INIS)

    Woo, C.K.; Ho, T.; Shiu, A.; Cheng, Y.S.; Horowitz, I.; Wang, J.

    2014-01-01

    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

  9. Outage management: A case study

    International Nuclear Information System (INIS)

    Haber, S.B.; Barriere, M.T.; Roberts, K.H.

    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

  10. 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

  11. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1. Volume 2, Part 1C: Analysis of core damage frequency from internal events for plant operational State 5 during a refueling outage, Main report (Sections 11--14)

    International Nuclear Information System (INIS)

    Whitehead, D.; Darby, J.; Yakle, J.

    1994-06-01

    This document contains the accident sequence analysis of internally initiated events for Grand Gulf, Unit 1 as it operates in the Low Power and Shutdown Plant Operational State 5 during a refueling outage. The report documents the methodology used during the analysis, describes the results from the application of the methodology, and compares the results with the results from two full power analyses performed on Grand Gulf

  12. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Analysis of core damage frequency from internal events for Plant Operational State 5 during a refueling outage. Volume 2, Part 2: Internal Events Appendices A to H

    International Nuclear Information System (INIS)

    Darby, J.; Whitehead, D.; Staple, B.; Dandini, V.

    1994-06-01

    This document contains the accident sequence analysis of internally initiated events for Grand Gulf, Unit 1 as it operates in the Low Power and Shutdown Plant Operational State 5 during a refueling outage. The report documents the methodology used during the analysis, describes the results from the application of the methodology, and compares the results with the results from two full power analyses performed on Grand Gulf

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

    International Nuclear Information System (INIS)

    Nemec, T.; Savli, S.; Cernilogar Radez, M.; Persic, A.; Pecek, V.; Stritar, A.

    2007-01-01

    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)

  14. Partnership - its contribution to outage success

    International Nuclear Information System (INIS)

    Gill, K.S.; Kirton-Darling, F.; Robinson, F.T.

    1996-01-01

    An innovative approach to developing the teamwork between the power station and the outage contractor has been pioneered over the past three years at the Bradwell nuclear power station in the UK, which houses two Magnox reactors. Magnox Electric and Rolls-Royce Nuclear Engineering Services are now undertaking their third outage under a partnership contract which has provided significant benefits to both parties. (Author)

  15. San Onofre - the evolution of outage management

    International Nuclear Information System (INIS)

    Slagle, K.A.

    1993-01-01

    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

  16. The four ''Ps'' of outage management

    International Nuclear Information System (INIS)

    Kuehn, S.E.

    1996-01-01

    This article describes how planning, partnering, preparation and people prevent poor outage performance. Boasting the best production costs in a decade, the US fleet of nuclear reactors is performing better than ever. Industry wide, production costs fell 7% to $20.02 per net megawatt hour (MWh) and output climbed 3% to 634million MWh. It doesn't take a nuclear physicists to realize that when base-loaded nuclear units are operated for long periods of time, near their technical potential, costs will fall and relative performance improves. Statistics for 1994 compiled by the Institute of Nuclear Operations (INPO) and the World Association of Nuclear Operators (WANO) showed the industry has steadily improved in most of the 10 industry-recognized categories. In 1994, Unit Capability Factor (the percentage of maximum energy generation a plant can supply to the grid) reached just under 82%, beating the 1995 goal and proving just how far the industry has come (62.7% in 1980) when improving plant operations

  17. Cell outage compensation in LTE networks: Algorithms and performance assessment

    NARCIS (Netherlands)

    Amirijoo, M.; Jorguseski, L.; Litjens, R.; Schmelz, L.C.

    2011-01-01

    Cell outage compensation is a self-healing function and as such part of the Self-Organising Networks concept for mobile wireless networks. It aims at mitigating the degradation of coverage, capacity and service quality caused by a cell or site level outage. Upon detection of such an outage, cell

  18. Maintenance, outages and chemistry really can be compatible

    International Nuclear Information System (INIS)

    Roberts, J.G.; Deaconescu, R.

    2006-01-01

    'Full text:' In their address to the Canadian Nuclear Society, Bruce Power's Chemistry Design staff will describe how maintenance and outages can impact negatively on chemistry control and asset protection. Considerations of material impacts and material condition have significant influences on the approach to, and control of, chemistry. This applies equally to operation as it does during unit and/or system outages. Ideas will be presented as to how to facilitate making maintenance, outages and chemistry compatible. It will be shown how the lack of such an approach can lead to disastrous results. (author)

  19. Evaluation of the Planned Outage Durations in EU-APR

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Byung Joon; Lee, Keun Sung [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    EU-APR has been designed to comply with European Utility Requirements (EUR) and nuclear design requirements of the European countries. And it is modified and improved from its original design of APR1400. The whole duration varies depending on items for additional process. Refueling and regular maintenance outage is comprised of basic processes and Main turbine-generator outage includes dismantling inspection of main generator and high pressure turbine as a critical path in addition to basic processes. In-Service Inspection Outage includes Automatic ultrasonic inspection on the upper side/lower side of a nuclear reactor as a critical path in addition to basic processes. The planned outage durations of EU-APR are optimized according to the above results. And they are complied with EUR Requirement (EUR 2.2.7.2.2 B), respectively. In addition, outage duration can be reduced with improved operating technology and more maintenance friendly environment including betterment of filling, drain and ventilation.

  20. Evaluation of the Planned Outage Durations in EU-APR

    International Nuclear Information System (INIS)

    Jung, Byung Joon; Lee, Keun Sung

    2016-01-01

    EU-APR has been designed to comply with European Utility Requirements (EUR) and nuclear design requirements of the European countries. And it is modified and improved from its original design of APR1400. The whole duration varies depending on items for additional process. Refueling and regular maintenance outage is comprised of basic processes and Main turbine-generator outage includes dismantling inspection of main generator and high pressure turbine as a critical path in addition to basic processes. In-Service Inspection Outage includes Automatic ultrasonic inspection on the upper side/lower side of a nuclear reactor as a critical path in addition to basic processes. The planned outage durations of EU-APR are optimized according to the above results. And they are complied with EUR Requirement (EUR 2.2.7.2.2 B), respectively. In addition, outage duration can be reduced with improved operating technology and more maintenance friendly environment including betterment of filling, drain and ventilation

  1. Maintenance, outages and chemistry really can be compatible

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, J.G.; Deaconescu, R. [Bruce Power, Tiverton, Ontario (Canada)

    2006-07-01

    'Full text:' In their address to the Canadian Nuclear Society, Bruce Power's Chemistry Design staff will describe how maintenance and outages can impact negatively on chemistry control and asset protection. Considerations of material impacts and material condition have significant influences on the approach to, and control of, chemistry. This applies equally to operation as it does during unit and/or system outages. Ideas will be presented as to how to facilitate making maintenance, outages and chemistry compatible. It will be shown how the lack of such an approach can lead to disastrous results. (author)

  2. The System 80+ standard plant design reduces operations and maintenance costs

    International Nuclear Information System (INIS)

    Chari, D.R.; Robertson, J.E.

    1998-01-01

    To be cost-competitive, nuclear power plants must maximize plant availability and minimize operations and maintenance (O and M) costs. A plant whose design supports these goals will generate more power at less cost and thereby have a lower unit generating cost. The ABB Combustion Engineering Nuclear Systems (ABB-CE) System 80+ Standard Nuclear Power Plant, rated at 1400 megawatts electric (MWe), is designed for high availability at reduced cost. To demonstrate that the duration of refueling outages, the major contributor to plant unavailability, can be shortened, ABB-CE developed a detailed plan that shows a System 80+ plant can safely perform a refueling and maintenance outage in 18 days. This is a significant reduction from the average current U.S. plant outages of 45 days, and is possible due to a two-part outage strategy: use System 80+ advanced system design features and relaxed technical specification (TS) time limits to shift some maintenance from outages to operating periods: and, use System 80+ structural, system, and component features, such as the larger operating floor, permanent pool seal, integral reactor head area cable tray system and missile shield, and longer life reactor coolant pump seals, to reduce the scope and duration of outage maintenance activities. Plant staffing level is the major variable, or controllable contributor to operations costs. ABB-CE worked with the Institute of Nuclear Power Operations (INPO) to perform detailed staffing analyses that show a System 80+ plant can be operated reliably with 30 percent less staff than currently operating nuclear plants of similar size. Safety was not sacrificed when ABB-CE developed the System 80+ refueling outage plan and staffing level. The outage plan was developed utilizing a defense-in-depth concept for shutdown safety. The defense in-depth concept is implemented via systematic control of outage risk evaluation (SCORE) cards. The SCORE cards identify primary and alternate means of

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

    International Nuclear Information System (INIS)

    Jakabe, Hideo; Maruyama, Yoshinaga

    1996-01-01

    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.)

  4. Application of 4-Face Fuel Visual Inspection System during Outage in Nuclear Power Plant

    International Nuclear Information System (INIS)

    Shin, J. C.; Kim, J. I.; Choi, C. B.; Kim, Y. C.; Kang, C. B.

    2008-01-01

    Recently, as a measure to reduce an outage duration in nuclear power plants (NPPs), a four-face fuel visual inspection system (4-FFVIS) built in 4 cameras was introduced by Ahlberg Electronics, Sweden. The 4- FFVIS is used to inspect the external appearance of irradiated fuel assemblies in order to confirm their integrity against mechanical defects and foreign materials. Until now, however, a typical one-face fuel inspection system(1-FFVIS) has been world-widely utilized in NPPs. The 1-FFVIS requires four turns with 90 degree to inspect every face of the fuel assembly, causing a relatively long inspecting time. But the 4- FFVIS allow us to inspect every face of the fuel assembly at the same time. The inspection time with the 4-FFVIS may be less than two minutes per fuel assembly, whereas that with the 1-FFVIS is about six minutes per fuel assembly. In viewpoint of this merit, the 4-FFVIS is expected to be world-widely used in the near future. In this paper, the technical requirements necessary to develop the 4-FFVIS as well as some improvements to complement the current 4-FFVIS are described

  5. 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.

  6. Reactor outage schedule (tentative)

    Energy Technology Data Exchange (ETDEWEB)

    Walton, R.P.

    1969-11-01

    This single page document is the November 1, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the production reactor.

  7. Reactor outage schedule (tentative)

    Energy Technology Data Exchange (ETDEWEB)

    Walton, R.P.

    1969-10-01

    This single page document is the October 1, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production Reactor.

  8. Reactor outage schedule (tentative)

    Energy Technology Data Exchange (ETDEWEB)

    Walton, R.P.

    1969-10-15

    This single page document is the October 15, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production Reactor.

  9. Reactor outage schedule (tentative)

    Energy Technology Data Exchange (ETDEWEB)

    Walton, R.P.

    1969-09-15

    This single page document is the September 15, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production Reactor.

  10. Reactor outage schedule (tentative)

    Energy Technology Data Exchange (ETDEWEB)

    Walton, R.P.

    1969-12-15

    This single page document is the December 16, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production reactor.

  11. Reactor outage schedule (tentative)

    Energy Technology Data Exchange (ETDEWEB)

    Walton, R.P.

    1969-12-01

    This single page document is the December 1, 1969 reactor refueling outage schedule for the Hanford Production Reactor. It also contains data on the amounts and types of fuels to be loaded and relocated in the Production reactor.

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

    International Nuclear Information System (INIS)

    Krajnc, J.; Skaler, F.; Basic, I.; Kocnar, R.

    1999-01-01

    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)

  13. Line outage contingency analysis including the system islanding scenario

    Energy Technology Data Exchange (ETDEWEB)

    Hazarika, D.; Bhuyan, S. [Assam Engineering College, Jalukbari, Guwahati 781013 (India); Chowdhury, S.P. [Jadavpur University, Jadavpur, Kolkata 700 032 (India)

    2006-05-15

    The paper describes an algorithm for determining the line outage contingency of a line taking into account of line over load effect in remaining lines and subsequent tripping of over loaded line(s) leading to possible system split or islanding of a power system. The optimally ordered sparse [B'], [B'] matrices for the integrated system are used for load flow analysis to determine modified values of voltage phase angles [{delta}] and bus voltages [V] to determine the over loading effect on the remaining lines due to outage of a selected line outage contingency. In case of over loading in remaining line(s), the over loaded lines are removed from the system and a topology processor is used to find the islands. A fast decoupled load flow (FDLF) analysis is carried out for finding out the system variables for the islanded (or single island) system by incorporating appropriate modification in the [B'] and [B'] matrices of the integrated system. Line outage indices based on line overload, loss of load, loss of generation and static voltage stability are computed to indicate severity of a line outage of a selected line. (author)

  14. Saving doses by outage planning strategy and architectural arrangements

    International Nuclear Information System (INIS)

    Wahlstroem, B.

    1993-01-01

    All radiation doses come out as a result of dose rate and exposure time, and the main part of the occupational exposure is caused during outages. While every reasonable attempt should be made to lower the dose rates, the other factor, the exposure time, may not be forgotten. The paper presents possible ways of saving man-hours in the controlled zone by outage planning strategy. And every saved man-hour means a saved radiation dose. At Loviisa NPS also some special architectural arrangements contribute to shortening the outage time, thus saving doses

  15. 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.

  16. Assessment and Application of the ROSE Code for Reactor Outage Thermal-Hydraulic and Safety Analysis

    International Nuclear Information System (INIS)

    Liang, Thomas K.S.; Ko, F.-K.; Dai, L.-C.

    2001-01-01

    The currently available tools, such as RELAP5, RETRAN, and others, cannot easily and correctly perform the task of analyzing the system behavior during plant outages. Therefore, a medium-sized program aiming at reactor outage simulation and evaluation, such as midloop operation (MLO) with loss of residual heat removal (RHR), has been developed. Important thermal-hydraulic processes involved during MLO with loss of RHR can be properly simulated by the newly developed reactor outage simulation and evaluation (ROSE) code. The two-region approach with a modified two-fluid model has been adopted to be the theoretical basis of the ROSE code.To verify the analytical model in the first step, posttest calculations against the integral midloop experiments with loss of RHR have been performed. The excellent simulation capacity of the ROSE code against the Institute of Nuclear Energy Research Integral System Test Facility test data is demonstrated. To further mature the ROSE code in simulating a full-sized pressurized water reactor, assessment against the WGOTHIC code and the Maanshan momentary-loss-of-RHR event has been undertaken. The successfully assessed ROSE code is then applied to evaluate the abnormal operation procedure (AOP) with loss of RHR during MLO (AOP 537.4) for the Maanshan plant. The ROSE code also has been successfully transplanted into the Maanshan training simulator to support operator training. How the simulator was upgraded by the ROSE code for MLO will be presented in the future

  17. Line outage contingency analysis including the system islanding ...

    African Journals Online (AJOL)

    The optimally ordered sparse [Bʹ], [Bʺ] matrices for the integrated system are used for load flow analysis to determine modified values of voltage phase angles [d] and bus voltages [V] to determine the over loading effect on the remaining lines due to outage of a selected line outage contingency. In case of over loading in ...

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

    International Nuclear Information System (INIS)

    Praktiknjo, Aaron J.; Hähnel, Alexander; Erdmann, Georg

    2011-01-01

    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.

  19. Risk-based evaluation of allowed outage time and surveillance test interval extensions for nuclear power plants

    International Nuclear Information System (INIS)

    Gibelli, Sonia Maria Orlando

    2008-03-01

    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)

  20. 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.

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

    KAUST Repository

    Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

    2016-01-01

    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.

  2. Estimating Power Outage Cost based on a Survey for Industrial Customers

    Science.gov (United States)

    Yoshida, Yoshikuni; Matsuhashi, Ryuji

    A survey was conducted on power outage cost for industrial customers. 5139 factories, which are designated energy management factories in Japan, answered their power consumption and the loss of production value due to the power outage in an hour in summer weekday. The median of unit cost of power outage of whole sectors is estimated as 672 yen/kWh. The sector of services for amusement and hobbies and the sector of manufacture of information and communication electronics equipment relatively have higher unit cost of power outage. Direct damage cost from power outage in whole sectors reaches 77 billion yen. Then utilizing input-output analysis, we estimated indirect damage cost that is caused by the repercussion of production halt. Indirect damage cost in whole sectors reaches 91 billion yen. The sector of wholesale and retail trade has the largest direct damage cost. The sector of manufacture of transportation equipment has the largest indirect damage cost.

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

    International Nuclear Information System (INIS)

    Turner, F.P.P.; Katrichak, A.M.; Dwyer, A.; Edwards, D.; Ibrahim, A.

    1994-01-01

    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

  4. Integrated services as the key to the optimisation of refueling outages

    International Nuclear Information System (INIS)

    Ortega, Juan; Gonzalez, Roberto; Gutierrez, Jose E.

    2010-01-01

    Refueling outages at nuclear power plants are subject to demanding improvement criteria in each and every one of the activities scheduled. The management of activities on the refueling floor, including the phases of opening and closing of the reactor vessel and associated tasks relating to the reactor internals, the unloading, loading and management of the irradiated fuel and activities requested for the in-service inspection of essential primary circuit components, are interventions that have an impact on the refueling critical path and whose overall integration allows for significant optimization of the entire management of this fundamental refueling activity. For several years now, ENUSA, as the company specializing in irradiated fuel services, TECNATOM as the company responsible for the in-service inspection of critical primary side components and Westinghouse as the technology provider and specialist in the supply of plant support services, have together formed a solid working team offering this integrated refueling service to the Spanish plants. Today, the new and heightened demands regarding the training and specialization of the personnel participating in refueling outages, the need to consider contingencies in the activities scheduled and the objectives relating to the ALARA concept and safe operations require that this service include new activities providing synergies and leading to higher levels of commitment to excellence. This paper will present the service model developed, the most significant activities integrated in the service and the advantages and milestones achieved and reached during this period, compared to the conventional distributed functions model. Likewise, an analysis will be made of the new challenges that are being addressed, with a view to bringing about a more global integration. (authors)

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

    International Nuclear Information System (INIS)

    Denny, V.E.; Wassel, A.T.; Issacci, F.; Pal Kalra, S.

    2004-01-01

    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)

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

    International Nuclear Information System (INIS)

    Gotcheva, N.; Macchi, L.; Oedewald, P.; Eitrheim, M.H.R.; Axelsson, C.; Reiman, T.; Pietikaeinen, E.

    2013-04-01

    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)

  7. 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)

  8. Remote-automated inspection and maintenance of nuclear power plant equipment

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Masayoshi; Nakano, Yoshiyuki

    1984-12-01

    Employing remote-control inspection and maintenance equipment in nuclear power plants increases the plant availability by decreasing the annual shutdown time (outage), as well as radiation exposure and man-power. This paper presents an outline of the latest designs for an automatic refueling machine, a control rod drive handling machine, a fuel preparation machine, and a main steam line plug, which were supplied to the Fukushima Dai-Ni No. 2 Plant of the Tokyo Electric Power Co., Inc. (Fukushima 2-2). Also, the up-to-date developments of other new automatic machines, such as a CRD disassembly and cleaning system, spent fuel channel box volume reduction equipment, and robotics for nuclear plant use are presented.

  9. Availability analysis of United States BWR IV electrical generation plants

    International Nuclear Information System (INIS)

    Renick, D.H.; Li, F.; Todreas, N.E.

    1998-01-01

    Availability, as quantified by power output levels, from all active U.S. BWR IV plants were analyzed over a seven and a half year period to determine the operational characteristics of these plants throughout an operating cycle. The operational data were examined for infant mortality, end of cycle decreased availability, and seasonal availability variations. Scheduled outages were also examined to determine the industry's current approach to planning maintenance outages. The results of this study show that nuclear power plants do suffer significant infant mortality following a refueling outage. And while they do not suffer an end of cycle decrease in availability, a mid-cycle period of decreased availability is evident. This period of decreased availability is due to a combination of increased forced unavailability and seasonally scheduled maintenance and refueling outages. These findings form the start of a rational approach to increasing plant availability. (author)

  10. 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.

  11. Estimating the Propagation of Interdependent Cascading Outages with Multi-Type Branching Processes

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Junjian; Ju, Wenyun; Sun, Kai

    2016-01-01

    In this paper, the multi-type branching process is applied to describe the statistics and interdependencies of line outages, the load shed, and isolated buses. The offspring mean matrix of the multi-type branching process is estimated by the Expectation Maximization (EM) algorithm and can quantify the extent of outage propagation. The joint distribution of two types of outages is estimated by the multi-type branching process via the Lagrange-Good inversion. The proposed model is tested with data generated by the AC OPA cascading simulations on the IEEE 118-bus system. The largest eigenvalues of the offspring mean matrix indicate that the system is closer to criticality when considering the interdependence of different types of outages. Compared with empirically estimating the joint distribution of the total outages, good estimate is obtained by using the multitype branching process with a much smaller number of cascades, thus greatly improving the efficiency. It is shown that the multitype branching process can effectively predict the distribution of the load shed and isolated buses and their conditional largest possible total outages even when there are no data of them.

  12. ERDA LWR plant technology program: role of government/industry in improving LWR performance

    International Nuclear Information System (INIS)

    1975-01-01

    Information is presented under the following chapter headings: executive summary; LWR plant outages; LWR plant construction delays and cancellations; programs addressing plant outages, construction delays, and cancellations; need for additional programs to remedy continuing problems; criteria for government role in LWR commercialization; and the proposed government program

  13. Verification and Enhancement of VIIRS Day-Night Band Power Outage Detection Product

    Science.gov (United States)

    Burke, A.; Schultz, L. A.; Omitaomu, O.; Molthan, A.; Cole, T.; Griffin, R.

    2017-12-01

    The NASA SPoRT (Short-term Prediction Research and Transition) Center has collaborated with scientists at NASA Goddard Space Flight Center to create a power outage detection product from radiance data obtained by the VIIRS (Visible Infrared Imaging Radiometer Suite) sensor aboard the Suomi-NPP satellite. This product uses a composite of pre-event radiance values from the VIIRS Day-Night Band to establish a baseline of "normal" nighttime lights for a study area. Then, after a severe weather event or other disaster, post-event images are compared to the composite to generate a percent-of-normal radiance product to identify areas that are experiencing outages and to aid in disaster response and monitor recovery. This project will use ground-truth county-level outage data provided by Oak Ridge National Laboratory (ORNL) in order validate the product and to establish a percent-of-normal threshold for identifying power outages. Once a threshold is found, ORNL's LandScan Global population data will be combined with the product to estimate how many electrical customers are being affected by power outages after a disaster. Two case studies will be explored to examine power outage recovery after severe weather events, including Hurricane Matthew from 2016 and the Washington D.C. Derecho event of 2012.

  14. Risk-based assessment of the allowable outage times for the unit 1 leningrad nuclear power plant ECCS components

    International Nuclear Information System (INIS)

    Koukhar, Sergey; Vinnikov, Bronislav

    2009-01-01

    Present paper describes a method for risk - informed assessment of the Allowable Outage Times (AOTs). The AOT is the time, when components of a safety system allowed to be out of service during power operation or during shutdown operation off a plant. If the components are not restored during the time, the plant in operation must be shut down or the plant in a given shutdown mode has to go to safer shutdown mode. Application of the method is also provided for the equipment of the Unit 1 Leningrad NPP ECCS components. For solution of the problem it is necessary to carry out two series of computations using a Living PSA model, level 1. In the first series of the computations the core damage frequency (CDFb) for the base configuration of the plant is determined (there is no equipment out of service). Here the symbol 'b' means the base configuration of a plant. In the second series of the computations the core damage frequency (CDFi) for the configuration of the plant with the component (which is out of service) is calculated. That is here CDFi is determined for the failure probability of the component equal to 1.0 (component 'i' is unavailable). Then it is necessary to determine so called Risk Increase Factor (RIF) using the following ratio: RIFi = CDFi / CDFb. At last the AOT is calculated with the help of the ratio: AOTi = Tppr / RIFi, where Tppr is a period of time between two Planned Preventive Repairs (PPRs). 1. Using the risk based approach the AOTs were calculated for a set of the components of the Unit 1 Leningrad NPP ECCS components. 2. The main conclusion from the analysis is that the current deterministic AOTs for the ECCS components are conservative and should be extended. 3. The risk based extension of the AOTs for the ECCS components can prevent the Unit 1 Leningrad NPP to enter into the operating modes with increased risk. (author)

  15. Availability Improvement of German Nuclear Power Plants

    International Nuclear Information System (INIS)

    Wilhelm, Oliver

    2008-01-01

    High availability is important for the safety and economical performance of Nuclear Power Plants (NPP). The strategy for availability improvement in a typical German PWR shall be discussed here. Key parameters for strategy development are plant design, availability of safety systems, component reliability, preventive maintenance and outage organization. Plant design, availability of safety systems and component reliability are to a greater extent given parameters that can hardly be influenced after the construction of the plant. But they set the frame for maintenance and outage organisation which have shown to have a large influence on the availability of the plant. (author)

  16. Does Your Domestic Photovoltaic Energy System Survive Grid Outages?

    Directory of Open Access Journals (Sweden)

    Marijn R. Jongerden

    2016-09-01

    Full Text Available Domestic renewable energy systems, including photovoltaic energy generation, as well as local storage, are becoming increasingly popular and economically feasible, but do come with a wide range of options. Hence, it can be difficult to match their specification to specific customer’s needs. Next to the usage-specific demand profiles and location-specific production profiles, local energy storage through the use of batteries is becoming increasingly important, since it allows one to balance variations in production and demand, either locally or via the grid. Moreover, local storage can also help to ensure a continuous energy supply in the presence of grid outages, at least for a while. Hybrid Petri net (HPN models allow one to analyze the effect of different battery management strategies on the continuity of such energy systems in the case of grid outages. The current paper focuses on one of these strategies, the so-called smart strategy, that reserves a certain percentage of the battery capacity to be only used in case of grid outages. Additionally, we introduce a new strategy that makes better use of the reserved backup capacity, by reducing the demand in the presence of a grid outage through a prioritization mechanism. This new strategy, called power-save, only allows the essential (high-priority demand to draw from the battery during power outages. We show that this new strategy outperforms previously-proposed strategies through a careful analysis of a number of scenarios and for a selection of survivability measures, such as minimum survivability per day, number of survivable hours per day, minimum survivability per year and various survivability quantiles.

  17. Development of an Overview Display to Allow Advanced Outage Control Center Management to Quickly Evaluate Outage Status

    Energy Technology Data Exchange (ETDEWEB)

    St Germain, Shawn Walter [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hugo, Jacques Victor [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    This report describes recent advances made in developing a framework for the design of visual outage information presentation, as well as an overview of the scientific principles that informed the development of the visualizations.

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

    International Nuclear Information System (INIS)

    Anahara, N.; Yamada, M.; Kataoka, H.

    2000-01-01

    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

  19. Distributed power-line outage detection based on wide area measurement system.

    Science.gov (United States)

    Zhao, Liang; Song, Wen-Zhan

    2014-07-21

    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.

  20. Hybrid Cascading Outage Analysis of Extreme Events with Optimized Corrective Actions

    Energy Technology Data Exchange (ETDEWEB)

    Vallem, Mallikarjuna R.; Vyakaranam, Bharat GNVSR; Holzer, Jesse T.; Samaan, Nader A.; Makarov, Yuri V.; Diao, Ruisheng; Huang, Qiuhua; Ke, Xinda

    2017-10-19

    Power system are vulnerable to extreme contingencies (like an outage of a major generating substation) that can cause significant generation and load loss and can lead to further cascading outages of other transmission facilities and generators in the system. Some cascading outages are seen within minutes following a major contingency, which may not be captured exclusively using the dynamic simulation of the power system. The utilities plan for contingencies either based on dynamic or steady state analysis separately which may not accurately capture the impact of one process on the other. We address this gap in cascading outage analysis by developing Dynamic Contingency Analysis Tool (DCAT) that can analyze hybrid dynamic and steady state behavior of the power system, including protection system models in dynamic simulations, and simulating corrective actions in post-transient steady state conditions. One of the important implemented steady state processes is to mimic operator corrective actions to mitigate aggravated states caused by dynamic cascading. This paper presents an Optimal Power Flow (OPF) based formulation for selecting corrective actions that utility operators can take during major contingency and thus automate the hybrid dynamic-steady state cascading outage process. The improved DCAT framework with OPF based corrective actions is demonstrated on IEEE 300 bus test system.

  1. 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.

  2. Wolsong Unit 1 restart chemistry procedures during retubing outage

    International Nuclear Information System (INIS)

    Yun, Hyunran; Lee, Sarang; Moon, Yunyong; Kim, Seoyul

    2015-01-01

    Lay-up is aimed at protecting systems from degradation during outage, mainly by minimizing corrosion and particularly, when the outage is longer than 16 weeks. Due to the intrinsic design of CANDU reactors, their horizontal fuel channels should be replaced for another service life time. This poster presents the lay-up guidelines and methods recommended for re-tubing outage based on the first re-tubing operation made in Korea (at the Wolsung Unit 1). It is shown that dry lay-up with specific gas blanket was the sole choice for the primary heat transfer system, the moderator system and the steam cycle system while wet lay-up under circulation was recommended for the end shield cooling system and the liquid zone control system. The water filled part of steam generators, of the liquid zone control system and of the end shield cooling system was maintained normal

  3. 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.

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

    KAUST Repository

    Alabbasi, Abdulrahman; Rezki, Zouheir; Shihada, Basem

    2016-01-01

    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

  5. Guide for prioritizing power plant productivity improvement projects: handbook of availability improvement methodology

    International Nuclear Information System (INIS)

    1981-01-01

    As part of its program to help improve electrical power plant productivity, the Department of Energy (DOE) has developed a methodology for evaluating productivity improvement projects. This handbook presents a simplified version of this methodology called the Availability Improvement Methodology (AIM), which provides a systematic approach for prioritizing plant improvement projects. Also included in this handbook is a description of data taking requirements necessary to support the AIM methodology, benefit/cost analysis, and root cause analysis for tracing persistent power plant problems. In applying the AIM methodology, utility engineers should be mindful that replacement power costs are frequently greater for forced outages than for planned outages. Equivalent availability includes both. A cost-effective ranking of alternative plant improvement projects must discern between those projects which will reduce forced outages and those which might reduce planned outages. As is the case with any analytical procedure, engineering judgement must be exercised with respect to results of purely mathematical calculations

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

    International Nuclear Information System (INIS)

    Han, S.-R.; Guikema, Seth D.; Quiring, Steven M.; Lee, Kyung-Ho; Rosowsky, David; Davidson, Rachel A.

    2009-01-01

    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

  7. 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.

  8. Outage capacity of multicarrier systems

    KAUST Repository

    Yilmaz, Ferkan; Alouini, Mohamed-Slim

    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.

  9. Allowable outage analysis for the LOFT CIS and reflood assist bypass valves

    International Nuclear Information System (INIS)

    Trainer, J.E.; Matthews, S.D.

    1977-06-01

    To determine the outage time allowable for a typical 1 of 2 redundant valve configuration, a Markov model was created to analyze the various operating states for the valves. Since no performance criteria have been specified, an availability model was constructed with regard to the valve outage

  10. Evaluation of potential severe accidents during low power and shutdown operations at Surry: Unit 1, Volume 1

    International Nuclear Information System (INIS)

    Chu, T.L.; Pratt, W.T.

    1995-10-01

    This document contains a summarization of the results and insights from the Level 1 accident sequence analyses of internally initiated events, internally initiated fire and flood events, seismically initiated events, and the Level 2/3 risk analysis of internally initiated events (excluding fire and flood) for Surry, Unit 1. The analysis was confined to mid-loop operation, which can occur during three plant operational states (identified as POSs R6 and R10 during a refueling outage, and POS D6 during drained maintenance). The report summarizes the Level 1 information contained in Volumes 2--5 and the Level 2/3 information contained in Volume 6 of NUREG/CR-6144

  11. Evaluation of potential severe accidents during low power and shutdown operations at Surry: Unit 1, Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L.; Pratt, W.T. [eds.; Musicki, Z. [Brookhaven National Lab., Upton, NY (United States)

    1995-10-01

    This document contains a summarization of the results and insights from the Level 1 accident sequence analyses of internally initiated events, internally initiated fire and flood events, seismically initiated events, and the Level 2/3 risk analysis of internally initiated events (excluding fire and flood) for Surry, Unit 1. The analysis was confined to mid-loop operation, which can occur during three plant operational states (identified as POSs R6 and R10 during a refueling outage, and POS D6 during drained maintenance). The report summarizes the Level 1 information contained in Volumes 2--5 and the Level 2/3 information contained in Volume 6 of NUREG/CR-6144.

  12. Upgrading BWR training simulators for annual outage operation training

    International Nuclear Information System (INIS)

    Yamakabe, K.; Nakajima, A.; Shiyama, H.; Noji, K.; Okabe, N.; Murata, F.

    2006-01-01

    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)

  13. 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.

  14. Outage Analysis of Asymmetric RF-FSO Systems

    KAUST Repository

    Ansari, Imran Shafique; Abdallah, Mohamed M.; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

    2017-01-01

    In this work, the outage performance analysis of a dual-hop transmission system composed of asymmetric radio frequency (RF) channels cascaded with free-space optical (FSO) links is presented. The RF links are modeled by the Rayleigh fading

  15. Plant availability design aspects of Korean next generation reactor

    International Nuclear Information System (INIS)

    Woo Sang Lim; Ha Chung Beak

    1998-01-01

    The purpose of this paper is to describe the KNGR design concepts adopted for reducing forced outages and refueling outages, and current design changes, to assess their availability impacts compared to existing domestic nuclear power plants, and then to identify design directions for next design stage. (author)

  16. Enhanced outage prediction modeling for strong extratropical storms and hurricanes in the Northeastern United States

    Science.gov (United States)

    Cerrai, D.; Anagnostou, E. N.; Wanik, D. W.; Bhuiyan, M. A. E.; Zhang, X.; Yang, J.; Astitha, M.; Frediani, M. E.; Schwartz, C. S.; Pardakhti, M.

    2016-12-01

    The overwhelming majority of human activities need reliable electric power. Severe weather events can cause power outages, resulting in substantial economic losses and a temporary worsening of living conditions. Accurate prediction of these events and the communication of forecasted impacts to the affected utilities is necessary for efficient emergency preparedness and mitigation. The University of Connecticut Outage Prediction Model (OPM) uses regression tree models, high-resolution weather reanalysis and real-time weather forecasts (WRF and NCAR ensemble), airport station data, vegetation and electric grid characteristics and historical outage data to forecast the number and spatial distribution of outages in the power distribution grid located within dense vegetation. Recent OPM improvements consist of improved storm classification and addition of new predictive weather-related variables and are demonstrated using a leave-one-storm-out cross-validation based on 130 severe extratropical storms and two hurricanes (Sandy and Irene) in the Northeast US. We show that it is possible to predict the number of trouble spots causing outages in the electric grid with a median absolute percentage error as low as 27% for some storm types, and at most around 40%, in a scale that varies between four orders of magnitude, from few outages to tens of thousands. This outage information can be communicated to the electric utility to manage allocation of crews and equipment and minimize the recovery time for an upcoming storm hazard.

  17. Contribution of quality assurance to effective nuclear power plant operation

    International Nuclear Information System (INIS)

    Raisic, N.

    1984-01-01

    The regulatory requirements related to quality assurance (QA) serve as an effective mechanism in establishing and implementing the QA programme during the design, construction and operation of nuclear power plants. However, these requirements only relate to the equipment and activities concerning the safety of nuclear power plants; the decision as to their implementation on other non-safety-related equipment is left to the plant management. As a result, operation statistics show that the safety-related systems are performing satisfactorily and that they are not of serious concern to plant unavailability. On the other hand, non-safety-related equipment which is still vital to plant performances is more frequently responsible for plant outages and losses in electricity production. QA programmes implemented on such equipment are in principle less strict, unsystematic and, in a number of cases, non-existent. An attempt has been made to analyse the existing operating experience data in order to identify the correlation of outage statistics with QA programmes required by existing standards and their implementation practices, both in respect of programme coverage and intensity. Unfortunately, existing operating experience data cannot directly correlate plant performance with the QA programmes implemented in order to demonstrate the effectiveness of QA techniques to plant safety, reliability of plant equipment and plant availability. For these reasons an analysis is made of outage statistics to identify the modes and causes of outages and to relate them to existing QA requirements and practices. Some conclusions are deduced that relate to a possible improvement of plant performance by consequent implementation of QA requirements to the equipment and activities responsible for both plant safety and efficient electricity production, and by adequate grading of QA activities to obtain a cost-effective QA programme in plant operation. (author)

  18. 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.

  19. Operation of Finnish nuclear power plants

    International Nuclear Information System (INIS)

    Tossavainen, K.

    1990-12-01

    During the second quarter of 1990 the Finnish nuclear plant units Loviisa 1 and 2 and TVO and II were in commercial operation for most of the time. The feedwater pipe rupture at Loviisa 1 and the resulting inspections and repairs at both Loviisa plant units brought about an outage the overall duration of which was 32 days. The annual maintenance outages of the TVO plant units were arranged during the report period and their combined duration was 31.5 days. Nuclear electricity accounted for 35.3% of the total Finnish electricity production during this quarter. The load factor average of the nuclear power plant units was 83.0%. Three events occurred during the report period which are classified as Level 1 on the International Nuclear Event Scale: feedwater pipe rupture at Loviisa 1, control rod withdrawal at TVO I in a test during an outage when the hydraulic scram system was rendered inoperable and erroneous fuel bundle transfers during control rod drives maintenance at TVO II. Other events during this quarter are classified as Level Zero (Below Scale) on the International Nuclear Event Scale. Occupational radiation doses and external releases of radioactivity were considerably below authorised limits. Only small amounts of nuclides originating in nuclear power plants were detected in samples taken in the vicinity of nuclear power plants

  20. Outage analysis of blind cooperative diversity

    KAUST Repository

    Tourki, Kamel; Alouini, Mohamed-Slim

    2011-01-01

    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.

  1. 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.

  2. Risk-based evaluation of Allowed Outage Times (AOTs) considering risk of shutdown

    International Nuclear Information System (INIS)

    Mankamo, T.; Kim, I.S.; Samanta, P.K.

    1992-01-01

    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

  3. Qualification of FFA treatment for the water-steam cycle as an innovative lay-up strategy for the long term outage of a CANDU-6 reactor

    International Nuclear Information System (INIS)

    Ramminger, Ute; Fandrich, Jörg; Sainz, Ricardo; Ovando, Luis; Herrera, Cecilia; Mendizabal, Maribel; Dumon, Adriana; Chocron, Mauricio

    2014-01-01

    The majority of worldwide operating Nuclear Power Plants is older than 25 years, which is accompanied with extended outage duration due to large refurbishment and upgrade programs, e.g. Steam Generator Replacement and other large component replacement. For these long term outages adequate and cost effective preservation methods are required. Normally during outages, systems and components are drained and opened to atmosphere whereas wet surfaces and moisture condensation can result in uniform corrosion of carbon steel and eventually other materials; superimposed localized corrosion is possible in presence of impurities. For those systems there are in general two different lay-up methods possible. Dry lay-up by removing all water and humidity from the components or wet lay-up with demineralized and oxygen free water and additional corrosion inhibitors. Disadvantages of these lay-up methods are: High man power and hardware efforts for performing dry lay-up. Usage of hazardous chemicals like Hydrazine. Insufficient results of both lay-up methods in case of switching between dry and wet lay-up. To improve the lay-up concept for long term outages, AREVA GmbH developed an innovative concept using FFA (Film-Forming Amines) for secondary side system lay-up. The entire water-steam cycle including the Steam Generators is treated in one step without any negative impact on the treated structural materials. This technology has been applied for the first time at NPP Embalse. Embalse Nuclear Power Station consists of a CANDU-6 reactor of 648 MWe electrical output. It is in commercial operation since 1984. The shutdown for refurbishment and preparation for the second cycle of operation that includes among other tasks the replacement of the existing steam generators and power uprating has been scheduled for 2014, which causes the necessity of a lay-up optimization in the plant. This paper deals in detail with the qualification process of the FFA treatment considering the specifics

  4. Handbook of plant cell culture. Volume 2. Crop species

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, W.R.; Evans, D.A.; Ammirato, P.V.; Yamada, Y. (eds.)

    1984-01-01

    In this volume the state-of-the-art plant cell culture techniques described in the first volume are applied to several agricultural and horticultural crops. In 21 chapters, they include maize, oats, wheat, beans, red clover and other forage legumes, asparagus, celery, cassava, sweet potato, banana, pawpaw, apple, grapes, conifers, date palm, rubber, sugarcane and tobacco. Each chapter contains (1) detailed protocols to serve as the foundation for current research, (2) a critical review of the literature, and (3) in-depth evaluations of the potential shown by plant cell culture for crop improvement. The history and economic importance of each crop are discussed. This volume also includes an essay, ''Oil from plants'', by M. Calvin.

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

    International Nuclear Information System (INIS)

    Che, Moo Seong; Cheong, Chang Hyeon; Lee, Byeong Cheol

    1996-07-01

    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

  6. 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.

  7. Environmental determinants of unscheduled residential outages in the electrical power distribution of Phoenix, Arizona

    International Nuclear Information System (INIS)

    Maliszewski, Paul J.; Larson, Elisabeth K.; Perrings, Charles

    2012-01-01

    The sustainability of power infrastructures depends on their reliability. One test of the reliability of an infrastructure is its ability to function reliably in extreme environmental conditions. Effective planning for reliable electrical systems requires knowledge of unscheduled outage sources, including environmental and social factors. Despite many studies on the vulnerability of infrastructure systems, the effect of interacting environmental and infrastructural conditions on the reliability of urban residential power distribution remains an understudied problem. We model electric interruptions using outage data between the years of 2002 and 2005 across Phoenix, Arizona. Consistent with perceptions of increased exposure, overhead power lines positively correlate with unscheduled outages indicating underground cables are more resistant to failure. In the presence of overhead lines, the interaction between birds and vegetation as well as proximity to nearest desert areas and lakes are positive driving factors explaining much of the variation in unscheduled outages. Closeness to the nearest arterial road and the interaction between housing square footage and temperature are also significantly positive. A spatial error model was found to provide the best fit to the data. Resultant findings are useful for understanding and improving electrical infrastructure reliability. - Highlights: ► Unscheduled outages were related to interacting environmental and infrastructural conditions. ► Underground feeders are more resistant to failure. ► In the presence of overhead lines, birds, vegetation, and proximity to desert areas are positive driving factors. ► Proximity to arterial roads and a proxy for energy demand were significantly positive. ► Outages were most spatially dependent up to around 350 m.

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

    International Nuclear Information System (INIS)

    2005-01-01

    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)

  9. Outage Probability Analysis of FSO Links over Foggy Channel

    KAUST Repository

    Esmail, Maged Abdullah

    2017-02-22

    Outdoor Free space optic (FSO) communication systems are sensitive to atmospheric impairments such as turbulence and fog, in addition to being subject to pointing errors. Fog is particularly severe because it induces an attenuation that may vary from few dBs up to few hundreds of dBs per kilometer. Pointing errors also distort the link alignment and cause signal fading. In this paper, we investigate and analyze the FSO systems performance under fog conditions and pointing errors in terms of outage probability. We then study the impact of several effective communication mitigation techniques that can improve the system performance including multi-hop, transmit laser selection (TLS) and hybrid RF/FSO transmission. Closed-form expressions for the outage probability are derived and practical and comprehensive numerical examples are suggested to assess the obtained results. We found that the FSO system has limited performance that prevents applying FSO in wireless microcells that have a 500 m minimum cell radius. The performance degrades more when pointing errors appear. Increasing the transmitted power can improve the performance under light to moderate fog. However, under thick and dense fog the improvement is negligible. Using mitigation techniques can play a major role in improving the range and outage probability.

  10. Outage Probability Analysis of FSO Links over Foggy Channel

    KAUST Repository

    Esmail, Maged Abdullah; Fathallah, Habib; Alouini, Mohamed-Slim

    2017-01-01

    Outdoor Free space optic (FSO) communication systems are sensitive to atmospheric impairments such as turbulence and fog, in addition to being subject to pointing errors. Fog is particularly severe because it induces an attenuation that may vary from few dBs up to few hundreds of dBs per kilometer. Pointing errors also distort the link alignment and cause signal fading. In this paper, we investigate and analyze the FSO systems performance under fog conditions and pointing errors in terms of outage probability. We then study the impact of several effective communication mitigation techniques that can improve the system performance including multi-hop, transmit laser selection (TLS) and hybrid RF/FSO transmission. Closed-form expressions for the outage probability are derived and practical and comprehensive numerical examples are suggested to assess the obtained results. We found that the FSO system has limited performance that prevents applying FSO in wireless microcells that have a 500 m minimum cell radius. The performance degrades more when pointing errors appear. Increasing the transmitted power can improve the performance under light to moderate fog. However, under thick and dense fog the improvement is negligible. Using mitigation techniques can play a major role in improving the range and outage probability.

  11. Performance Shaping Factors Assessments and Application to PHWR Outages

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Woo

    2007-02-15

    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{sup -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

  12. Performance Shaping Factors Assessments and Application to PHWR Outages

    International Nuclear Information System (INIS)

    Lee, Seung Woo

    2007-02-01

    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

  13. Scale models: A proven cost-effective tool for outage planning

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R. [Commonwealth Edison Co., Morris, IL (United States); Segroves, R. [Sargent & Lundy, Chicago, IL (United States)

    1995-03-01

    As generation costs for operating nuclear stations have risen, more nuclear utilities have initiated efforts to improve cost effectiveness. Nuclear plant owners are also being challenged with lower radiation exposure limits and new revised radiation protection related regulations (10 CFR 20), which places further stress on their budgets. As source term reduction activities continue to lower radiation fields, reducing the amount of time spent in radiation fields becomes one of the most cost-effective ways of reducing radiation exposure. An effective approach for minimizing time spent in radiation areas is to use a physical scale model for worker orientation planning and monitoring maintenance, modifications, and outage activities. To meet the challenge of continued reduction in the annual cumulative radiation exposures, new cost-effective tools are required. One field-tested and proven tool is the physical scale model.

  14. Comparison and validation of statistical methods for predicting power outage durations in the event of hurricanes.

    Science.gov (United States)

    Nateghi, Roshanak; Guikema, Seth D; Quiring, Steven M

    2011-12-01

    This article compares statistical methods for modeling power outage durations during hurricanes and examines the predictive accuracy of these methods. Being able to make accurate predictions of power outage durations is valuable because the information can be used by utility companies to plan their restoration efforts more efficiently. This information can also help inform customers and public agencies of the expected outage times, enabling better collective response planning, and coordination of restoration efforts for other critical infrastructures that depend on electricity. In the long run, outage duration estimates for future storm scenarios may help utilities and public agencies better allocate risk management resources to balance the disruption from hurricanes with the cost of hardening power systems. We compare the out-of-sample predictive accuracy of five distinct statistical models for estimating power outage duration times caused by Hurricane Ivan in 2004. The methods compared include both regression models (accelerated failure time (AFT) and Cox proportional hazard models (Cox PH)) and data mining techniques (regression trees, Bayesian additive regression trees (BART), and multivariate additive regression splines). We then validate our models against two other hurricanes. Our results indicate that BART yields the best prediction accuracy and that it is possible to predict outage durations with reasonable accuracy. © 2011 Society for Risk Analysis.

  15. Replacement of outboard main steam isolation valves in a boiling water reactor plant

    Energy Technology Data Exchange (ETDEWEB)

    Schlereth, J.R.; Pennington, D.

    1996-12-01

    Most Boiling Water Reactor plants utilize wye pattern globe valves for main steam isolation valves for both inboard and outboard isolation. These valves have required a high degree of maintenance attention in order to pass the plant local leakage rate testing (LLRT) requirements at each outage. Northern States Power made a decision in 1993 to replace the outboard valves at it`s Monticello plant with double disc gate valves. The replacement of the outboard valves was completed during the fall outage in 1994. During the spring outage in April of 1996 the first LLRT testing was performed with excellent results. This presentation will address the decision process, time requirements and planning necessary to accomplish the task as well as the performance results and cost effectiveness of replacing these components.

  16. Replacement of outboard main steam isolation valves in a boiling water reactor plant

    International Nuclear Information System (INIS)

    Schlereth, J.R.; Pennington, D.

    1996-01-01

    Most Boiling Water Reactor plants utilize wye pattern globe valves for main steam isolation valves for both inboard and outboard isolation. These valves have required a high degree of maintenance attention in order to pass the plant local leakage rate testing (LLRT) requirements at each outage. Northern States Power made a decision in 1993 to replace the outboard valves at it's Monticello plant with double disc gate valves. The replacement of the outboard valves was completed during the fall outage in 1994. During the spring outage in April of 1996 the first LLRT testing was performed with excellent results. This presentation will address the decision process, time requirements and planning necessary to accomplish the task as well as the performance results and cost effectiveness of replacing these components

  17. Programming and organisation of unit outages

    International Nuclear Information System (INIS)

    Hadjidakis, Y.; Cezard, C.; Audierne, J.

    1997-01-01

    The unit outages are scheduled every 12 to 18 months for fuel reloading. The success of these shutdowns, with the whole of objectives (duration, dosimetry, costs), with maintaining the safety level, is an important stake for the competitiveness of the enterprise. In this article are described the planning, the experience return and the organisation of scheduled shutdowns which have contribute to the improvement of availability. (N.C.)

  18. Exact Outage Probability of Dual-Hop CSI-Assisted AF Relaying Over Nakagami-m Fading Channels

    KAUST Repository

    Xia, Minghua; Aissa, Sonia; Wu, Yik-Chung

    2012-01-01

    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.

  19. Synergistic Use of Nighttime Satellite Data, Electric Utility Infrastructure, and Ambient Population to Improve Power Outage Detections in Urban Areas

    Directory of Open Access Journals (Sweden)

    Tony A. Cole

    2017-03-01

    Full Text Available Natural and anthropogenic hazards are frequently responsible for disaster events, leading to damaged physical infrastructure, which can result in loss of electrical power for affected locations. Remotely-sensed, nighttime satellite imagery from the Suomi National Polar-orbiting Partnership (Suomi-NPP Visible Infrared Imaging Radiometer Suite (VIIRS Day/Night Band (DNB can monitor power outages in disaster-affected areas through the identification of missing city lights. When combined with locally-relevant geospatial information, these observations can be used to estimate power outages, defined as geographic locations requiring manual intervention to restore power. In this study, we produced a power outage product based on Suomi-NPP VIIRS DNB observations to estimate power outages following Hurricane Sandy in 2012. This product, combined with known power outage data and ambient population estimates, was then used to predict power outages in a layered, feedforward neural network model. We believe this is the first attempt to synergistically combine such data sources to quantitatively estimate power outages. The VIIRS DNB power outage product was able to identify initial loss of light following Hurricane Sandy, as well as the gradual restoration of electrical power. The neural network model predicted power outages with reasonable spatial accuracy, achieving Pearson coefficients (r between 0.48 and 0.58 across all folds. Our results show promise for producing a continental United States (CONUS- or global-scale power outage monitoring network using satellite imagery and locally-relevant geospatial data.

  20. Ratepayers should not fund IP-2 outage, NY Attorney General says

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The New York Attorney General is trying to block Consolidated Edison's effort to pay for an Indian Point nuclear plant outage through the fuel-adjustment clause on the grounds that the utility had repeated system warnings and should have taken action to prevent the leakage of water into the containment building. The utility rejects the assessment of personnel negligence and, blaming equipment failure, plans to replace its heat exchangers. The New York Public Service Commission approved Con Ed's use of the fuel-adjustment clause to pay for replacement power, but agrees that ratepayers should not pay the costs of negligence if the charges are proved. The Attorney General feels that Con Ed could legally challenge a later request for refunds. Other funding possibilities include nuclear-insurance policies or legal action against the equipment manufacturer

  1. Proceedings of the American power conference: Volume 61-1

    International Nuclear Information System (INIS)

    McBride, A.E.

    1999-01-01

    This is volume one of the proceedings of the American Power Conference of 1999. The topics of the papers include multi-skilled work forces for the next century; global climate change and mitigation; distributed generation prospects in an open market; US DOE--EPRI wind turbine verification program; operations and maintenance cost reduction strategies; surviving deregulation and competition; power markets risk management and trading; interconnected operations; commercializing reliability; utility automation; electrical impacts of facilities operation; training for the future; SOX/PM2.5/air toxic; turbine-generator plant advances; codes and standards -- competing globally; business opportunities; the changing regulatory environment; advanced fuel design and engineering analysis: mandate for competing under regulation; unit commitment and dispatch; strategies for the open market; outage management; distribution reliability; and NOX control

  2. POWER-GEN '90 conference papers: Volume 7 (Fossil plant performance availability and improvement) and Volume 8 (Nuclear power issues)

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    This is book 4 of papers presented at the Third International Exhibition and Conference for the Power Generation Industries, December 4-6, 1990. This book contains Volume 7, Fossil Plant Performance Availability and Improvement, and Volume 8, Nuclear Power Issues. The topics of the papers include computer applications in plant operations and maintenance, managing aging plants, plant improvements, plant operations and maintenance, the future of nuclear power, achieving cost effective plant operation, managing nuclear plant aging and license renewal, and the factors affecting a decision to build a new nuclear plant

  3. Outage Analysis of Asymmetric RF-FSO Systems

    KAUST Repository

    Ansari, Imran Shafique

    2017-03-20

    In this work, the outage performance analysis of a dual-hop transmission system composed of asymmetric radio frequency (RF) channels cascaded with free-space optical (FSO) links is presented. The RF links are modeled by the Rayleigh fading distribution and the FSO links are modeled by Malaga (M) turbulence distribution. The FSO links account for pointing errors and both types of detection techniques (i.e. heterodyne detection as well as intensity modulation/direct detection (IM/DD)). Transmit diversity is applied at the source, selection combining is applied at the destination, and the relay is equipped with single RF receive antenna and single aperture for relaying the information over FSO links. 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 such communication systems in terms of the Meijer\\'s G function 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.

  4. R and D proposals to improve outages operation. Methods, practices and tools

    International Nuclear Information System (INIS)

    Dionis, Francois

    2014-01-01

    This paper deals with outage operation improvement. It offers a number of tracks on the interactions between the operation activities and maintenance, with a methodological perspective and proposals concerning the Information System. On the methodological point of view, a clever plant systems modeling may allow representing the needed characteristics in order to optimize tagouts, alignment procedures and the schedule. Tools must be taken n into account for new tagout practices such as tags sharing. It is possible to take advantage of 2D drawings integrated into the information system in order to improve the data controls and to visualize operation activities. An integrated set of mobile applications should allow field operators to join the information system for a better and safer performance. (author)

  5. Verification and Enhancement of VIIRS Day-Night Band (DNB) Power Outage Detection Product

    Science.gov (United States)

    Burke, Angela; Schultz, Lori A.; Omitaomu, Olufemi; Molthan, Andrew L.; Cole, Tony; Griffin, Robert

    2017-01-01

    This case study of Hurricane Matthew (October 2016) uses the NASA Short-Term Prediction Research and Transition (SPoRT) Center DNB power outage product (using GSFC VIIRS DNB preliminary Black Marble product, Roman et al.. 2017) and 2013 LandScan Global population data to look for correlations between the post-event %-of-normal radiance and the utility company-reported outage numbers (obtained from EAGLE-1).

  6. Economic costs of electrical system instability and power outages caused by snakes on the Island of Guam

    Science.gov (United States)

    Fritts, T.H.

    2002-01-01

    The Brown Tree Snake, Boiga irregularis, is an introduced species on Guam where it causes frequent electrical power outages. The snake's high abundance, its propensity for climbing, and use of disturbed habitats all contribute to interruption of Guam's electrical service and the activities that depend on electrical power. Snakes have caused more than 1600 power outages in the 20-yr period of 1978–1997 and most recently nearly 200 outages per year. Single outages spanning the entire island and lasting 8 or more hours are estimated to cost in excess of $3,000,000 in lost productivity, but the costs of outages that involve only parts of the island or those of shorter durations are more difficult to quantify. Costs to the island's economy have exceeded $4.5 M $4.5M"> per year over a 7-yr period without considering repair costs, damage to electrical equipment, and lost revenues. Snakes pose the greatest problem on high voltage transmission lines, on transformers, and inside electrical substations.

  7. 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)

    1995-01-01

    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

  8. Cost effective snubber reduction program for nuclear power plants

    International Nuclear Information System (INIS)

    Adams, T.M.; Antaki, G.A.; Chang, K.C.

    1985-01-01

    Due to the stringent seismic requirements imposed on nuclear power plants, piping engineers have resorted to the extensive use of snubbers to support nuclear piping systems. The advantage of snubbers is that they provide dynamic restraint while allowing free thermal growth of the pipe. Unfortunately, as more plants go into operation, utilities have to face the costs of strict in-service inspection requirements and risks of unscheduled or extended plant outages associated with snubber failures. The snubber inspection requirements, defined in plant Technical Specifications, require periodic visual inspections of all snubbers and functional tests of a percentage of the plant snubbers, during refueling outages. For a typical 1000 Mw unit this represents from 50 to several hundred snubbers to be functionally tested at each refueling outage. Should failures occur during testing, the sample size must be further increased. Very quickly the costs and risks of extended shutdowns have led the industry to consider, and in many cases implement, snubber reduction programs. At the same time several changes in seismic design criteria have greatly facilitated the reduction of snubbers, making snubber elimination economically and technically attractive. In this paper we examine the costs and benefits of snubber reduction programs and propose a method for evaluating their cost benefits

  9. 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.

  10. Impact of Co-Channel Interference on the Outage Performance Under Multiple Type II Relay Environments

    KAUST Repository

    Choi, Seyeong; Alouini, Mohamed-Slim; Nam, Sung Sik

    2017-01-01

    In this paper, through an exact analysis of the outage probability, we investigate the impact of co-channel interference (CCI) on the outage performance of type II (or user equipment) relay under multiple-relay environments considering the selection combining-based relay selection scheme with the decode-and-forward protocol. We consider the signal to interference plus noise ratio (SINR) over both independent and identically distributed and independent but non-identically distributed fading channels. To fully take into account the effect of CCI, we adopt a more practical parameter such as the CCI coefficient. The major difficulty in the analysis resides in the determination of the statistics of the output SINR. To settle this problem, we first present the general but relatively simplified expressions for the statistics and then the related outage probability in closed-form. Furthermore, to consider more practical scenario, based on the fact that the number of participating relays can be random, we investigate the average outage probability by averaging the number of participating relays.

  11. Impact of Co-Channel Interference on the Outage Performance Under Multiple Type II Relay Environments

    KAUST Repository

    Choi, Seyeong

    2017-11-15

    In this paper, through an exact analysis of the outage probability, we investigate the impact of co-channel interference (CCI) on the outage performance of type II (or user equipment) relay under multiple-relay environments considering the selection combining-based relay selection scheme with the decode-and-forward protocol. We consider the signal to interference plus noise ratio (SINR) over both independent and identically distributed and independent but non-identically distributed fading channels. To fully take into account the effect of CCI, we adopt a more practical parameter such as the CCI coefficient. The major difficulty in the analysis resides in the determination of the statistics of the output SINR. To settle this problem, we first present the general but relatively simplified expressions for the statistics and then the related outage probability in closed-form. Furthermore, to consider more practical scenario, based on the fact that the number of participating relays can be random, we investigate the average outage probability by averaging the number of participating relays.

  12. 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.

  13. Outage Analysis and Optimization of SWIPT in Network-Coded Two-Way Relay Networks

    Directory of Open Access Journals (Sweden)

    Ruihong Jiang

    2017-01-01

    Full Text Available This paper investigates the outage performance of simultaneous wireless information and power transfer (SWIPT in network-coded two-way relay systems, where a relay first harvests energy from the signals transmitted by two sources and then uses the harvested energy to forward the received information to the two sources. We consider two transmission protocols, power splitting two-way relay (PS-TWR and time switching two-way relay (TS-TWR protocols. We present two explicit expressions for the system outage probability of the two protocols and further derive approximate expressions for them in high and low SNR cases. To explore the system performance limits, two optimization problems are formulated to minimize the system outage probability. Since the problems are nonconvex and have no known solution methods, a genetic algorithm- (GA- based algorithm is designed. Numerical and simulation results validate our theoretical analysis. It is shown that, by jointly optimizing the time assignment and SWIPT receiver parameters, a great performance gain can be achieved for both PS-TWR and TS-TWR. Moreover, the optimized PS-TWR always outperforms the optimized TS-TWR in terms of outage performance. Additionally, the effects of parameters including relay location and transmit powers are also discussed, which provide some insights for the SWIPT-enabled two-way relay networks.

  14. 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.

  15. Management of main generator condition during long term plant shut down at Higashidori Nuclear Power Station Unit 1

    International Nuclear Information System (INIS)

    Kato, Seiji

    2014-01-01

    Higashidori Nuclear Power Station Unit 1 shut down on February 6, 2011 to start 4th refuel outage. On March 11, 2011, we keep going refuel outage on this moment a large earthquake occurred and tsunami was generated following it which called 'Great East Japan Earthquake'. Refuel outage takes 3 ∼ 5 months normally but Higashidori NPS still keeping shut down over 3 years due to some issues. In this paper, we introduce about management of Main generator condition during long term plant shut down situation in addition to normal plant shut down situation to keep well. (author)

  16. Nuclear power plant operating experience, 1976

    International Nuclear Information System (INIS)

    1977-11-01

    This report is the third in a series of reports issued annually that summarize the operating experience of U.S. nuclear power plants in commercial operation. Power generation statistics, plant outages, reportable occurrences, fuel element performance, occupational radiation exposure and radioactive effluents for each plant are presented. Summary highlights of these areas are discussed. The report includes 1976 data from 55 plants--23 boiling water reactor plants and 32 pressurized water reactor plants

  17. Management of external support services for Almaraz Nuclear Power Plant

    International Nuclear Information System (INIS)

    Rayo Medina, A.; Lozano, J.M.

    1994-01-01

    Operation support services for a nuclear power plant have become increasingly important and voluminous during the power operation of the plant as well as during the shutdown and refuelling outage periods. Optimization of organization and management of these services entails a series of advantages and improvements aimed at the common objective of increasing plant availability and safety and eventually improving general operation results. This paper describes the existing operation support services at Almaraz nuclear power plant, with emphasis on site services, analysing the different possible options, their advantages and disadvantage with regard to plant organization and characteristics and describing, among others, the following aspects of these services: - Areas and specialities of required services - Scope of activities performed - Selection of candidate companies - Definition of technical and human resources - Supervision, coordination and control - Contracting and economic approach An evaluation is also made of the repercussions on the volume of workfromoperation support services rendered at Almaraz NPP by contracted companies, grouping them into three homogeneous areas (Full-Power Operation, Refuelling, and Design and Modifications) whose approach and execution are subject to different. (Author)

  18. Observations and insights from low power and shutdown studies: Grand Gulf Nuclear Power Plant during POS 5 of a refueling outage

    International Nuclear Information System (INIS)

    Whitehead, D.W.; Brown, T.D.; Forester, J.A.

    1995-04-01

    With the recent 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 (NRC), detailed probabilistic risk assessment (PRA) information from a boiling water reactor (BWR) for a specific time period in LP and S conditions became available for examination. This report contains 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 performed as part of this project to help determine the impact that model assumptions and data values had on the results from the original LP and S analysis. Specifically, this study makes observations on and develops insights from the estimates of core damage frequency and aggregate risk (early fatalities and total latent cancer fatalities) associated with operations during plant operational state (POS) 5 (i.e., basically cold shutdown as defined by Technical Specifications) during a refueling outage for traditional internal events. 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. A novel fusion methodology to bridge GPS outages for land vehicle positioning

    International Nuclear Information System (INIS)

    Chen, Wei; Li, Xu; Song, Xiang; Xu, Qimin; Li, Bin; Song, Xianghui

    2015-01-01

    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)

  20. The plant cytoskeleton controls regulatory volume increase.

    Science.gov (United States)

    Liu, Qiong; Qiao, Fei; Ismail, Ahmed; Chang, Xiaoli; Nick, Peter

    2013-09-01

    The ability to adjust cell volume is required for the adaptation to osmotic stress. Plant protoplasts can swell within seconds in response to hypoosmotic shock suggesting that membrane material is released from internal stores. Since the stability of plant membranes depends on submembraneous actin, we asked, whether this regulatory volume control depends on the cytoskeleton. As system we used two cell lines from grapevine which differ in their osmotic tolerance and observed that the cytoskeleton responded differently in these two cell lines. To quantify the ability for regulatory volume control, we used hydraulic conductivity (Lp) as readout and demonstrated a role of the cytoskeleton in protoplast swelling. Chelation of calcium, inhibition of calcium channels, or manipulation of membrane fluidity, did not significantly alter Lp, whereas direct manipulation of the cytoskeleton via specific chemical reagents, or indirectly, through the bacterial elicitor Harpin or activation of phospholipase D, was effective. By optochemical engineering of actin using a caged form of the phytohormone auxin we can break the symmetry of actin organisation resulting in a localised deformation of cell shape indicative of a locally increased Lp. We interpret our findings in terms of a model, where the submembraneous cytoskeleton controls the release of intracellular membrane stores during regulatory volume change. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Experience of oil in CANDU moderator during A831 planned outage at Bruce Power

    International Nuclear Information System (INIS)

    Ma, G.; Nashiem, R.; Matheson, S.; Stuart, C.; Roberts, J.G.

    2011-01-01

    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)

  2. Experience of oil in CANDU® moderator during A831 planned outage at Bruce Power

    International Nuclear Information System (INIS)

    Ma, G.; Nashiem, R.; Matheson, S.; Stuart, C.; Roberts, J.G.

    2010-01-01

    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)

  3. Experience of oil in CANDU® moderator during A831 planned outage at Bruce Power

    Energy Technology Data Exchange (ETDEWEB)

    Ma, G.; Nashiem, R.; Matheson, S. [Bruce Power, Tiverton, Ontario (Canada); Stuart, C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Roberts, J.G. [CANTECH Associates Ltd., Burlington, Ontario (Canada)

    2010-07-01

    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)

  4. Experience of oil in CANDU moderator during A831 planned outage at Bruce Power

    Energy Technology Data Exchange (ETDEWEB)

    Ma, G.; Nashiem, R.; Matheson, S. [Bruce Power, Tiverton, Ontario (Canada); Stuart, C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Roberts, J.G. [CANTECH Associates Ltd., Burlington, Ontario (Canada)

    2011-03-15

    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)

  5. Modernization of electric power systems of the Laguna Verde Nuclear Power Plant

    International Nuclear Information System (INIS)

    Gabaldon, M. A.; Gonzalez, J. J.; Prieto, I.

    2011-01-01

    The Power Increase Project of Laguna Verde Nuclear Plant has entailed the replacement, in one unique outage, of the main power electrical systems of the Plant (Isolated Phase Bars, Generator Circuit Breaker and Main Transformer) as well as the replacement of the Turbo-group. The simultaneous substitution of these entire system has never been done by any other Plant in the world, representing an engineering challenge that embraced the design of the new equipment up to the planning, coordination and management of the construction and commissioning works, which were successfully carried out by Iberdrola within the established outage period /47 days) for both units. (Author)

  6. 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.

  7. Power Allocation and Outage Probability Analysis for SDN-based Radio Access Networks

    Science.gov (United States)

    Zhao, Yongxu; Chen, Yueyun; Mai, Zhiyuan

    2018-01-01

    In this paper, performance of Access network Architecture based SDN (Software Defined Network) is analyzed with respect to the power allocation issue. A power allocation scheme PSO-PA (Particle Swarm Optimization-power allocation) algorithm is proposed, the proposed scheme is subjected to constant total power with the objective of minimizing system outage probability. The entire access network resource configuration is controlled by the SDN controller, then it sends the optimized power distribution factor to the base station source node (SN) and the relay node (RN). Simulation results show that the proposed scheme reduces the system outage probability at a low complexity.

  8. 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.

  9. Maintenance of French 900 MW PWR plants

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    This paper presents the doctrine and the aims of maintenance of EDF in the next few years. With an average age of 3.5 years, France's 900 MW PWRs, which now total 31, have overcome their growing pains. During the next few years EDF is aiming for a sharp increase in the availability factor of these plants which make up most of its nuclear thermal capacity, a reduction in the number of emergency outages, as great a cut back as possible in the period of programmed outages and the bringing down of the doses received by staff to the lowest possible level. Eventually the idea is to extend the operating life of plants as much as possible, perhaps to 40 or 50 years [fr

  10. Gas Reactor International Cooperative program. Pebble bed reactor plant: screening evaluation. Volume 2. Conceptual balance of plant design

    Energy Technology Data Exchange (ETDEWEB)

    1979-11-01

    This report consists of three volumes which describe the design concepts and screening evaluation for a 3000 MW(t) Pebble Bed Reactor Multiplex Plant (PBR-MX). The Multiplex plant produces both electricity and transportable chemical energy via the thermochemical pipeline (TCP). The evaluation was limited to a direct cycle plant which has the steam generators and steam reformers in the primary circuit. This volume describes the conceptual balance-of-plant (BOP) design and was prepared by United Engineers and Constructors, Inc. of Philadelphia, Pennsylvania. The major emphasis of the BOP study was a preliminary design of an overall plant to provide a basis for future studies.

  11. Gas Reactor International Cooperative program. Pebble bed reactor plant: screening evaluation. Volume 2. Conceptual balance of plant design

    International Nuclear Information System (INIS)

    1979-11-01

    This report consists of three volumes which describe the design concepts and screening evaluation for a 3000 MW(t) Pebble Bed Reactor Multiplex Plant (PBR-MX). The Multiplex plant produces both electricity and transportable chemical energy via the thermochemical pipeline (TCP). The evaluation was limited to a direct cycle plant which has the steam generators and steam reformers in the primary circuit. This volume describes the conceptual balance-of-plant (BOP) design and was prepared by United Engineers and Constructors, Inc. of Philadelphia, Pennsylvania. The major emphasis of the BOP study was a preliminary design of an overall plant to provide a basis for future studies

  12. Contributions of welding technology to power plant performance

    International Nuclear Information System (INIS)

    Childs, W.J.

    1995-01-01

    Welding repairs can be a very major factor in the time and cost of maintenance outages of a power plant. The use of advanced equipment and procedures for welding can contribute significantly to reducing maintenance costs and increasing reliability. Plant failures have too often been caused by problems associated with welding, some due to improper choice of base materials, others due to welding defects. For example, stress corrosion cracking in weldments in BWR austenitic stainless steel piping was a major source of loss of availability in the 1980s. Examples of the use of improved welding equipment and procedures has been demonstrated to reduce outage time and improved weld integrity in several major areas. New welding techniques, such as laser welding, have the potential for addressing maintenance problems that can not be addressed at all with conventional welding technology and/or may provide a means of reducing greatly the time and cost of welding fabrications or repair. Methods of ensuring that the best available technology is applied in weld repair is a major problem today in the utility industry. Solutions need to be sought to remedy this situation. The key role of welding in minimizing plant outages is being recognized and steps taken to further the development and use of optimum technology

  13. Plant Outage Time Savings Provided by Subcritical Physics Testing at Vogtle Unit 2

    International Nuclear Information System (INIS)

    Cupp, Philip; Heibel, M.D.

    2006-01-01

    The most recent core reload design verification physics testing done at Southern Nuclear Company's (SNC) Vogtle Unit 2, performed prior to initial power operations in operating cycle 12, was successfully completed while the reactor was at least 1% ΔK/K subcritical. The testing program used was the first application of the Subcritical Physics Testing (SPT) program developed by the Westinghouse Electric Company LLC. The SPT program centers on the application of the Westinghouse Subcritical Rod Worth Measurement (SRWM) methodology that was developed in cooperation with the Vogtle Reactor Engineering staff. The SRWM methodology received U. S. Nuclear Regulatory Commission (NRC) approval in August of 2005. The first application of the SPT program occurred at Vogtle Unit 2 in October of 2005. The results of the core design verification measurements obtained during the SPT program demonstrated excellent agreement with prediction, demonstrating that the predicted core characteristics were in excellent agreement with the actual operating characteristics of the core. This paper presents an overview of the SPT Program used at Vogtle Unit 2 during operating cycle 12, and a discussion of the critical path outage time savings the SPT program is capable of providing. (authors)

  14. Cost of Lightning Strike Related Outages of Visual Navigational Aids at Airports in the United States

    Science.gov (United States)

    Rakas, J.; Nikolic, M.; Bauranov, A.

    2017-12-01

    Lightning storms are a serious hazard that can cause damage to vital human infrastructure. In aviation, lightning strikes cause outages to air traffic control equipment and facilities that result in major disruptions in the network, causing delays and financial costs measured in the millions of dollars. Failure of critical systems, such as Visual Navigational Aids (Visual NAVAIDS), are particularly dangerous since NAVAIDS are an essential part of landing procedures. Precision instrument approach, an operation utilized during the poor visibility conditions, utilizes several of these systems, and their failure leads to holding patterns and ultimately diversions to other airports. These disruptions lead to both ground and airborne delay. Accurate prediction of these outages and their costs is a key prerequisite for successful investment planning. The air traffic management and control sector need accurate information to successfully plan maintenance and develop a more robust system under the threat of increasing lightning rates. To analyze the issue, we couple the Remote Monitoring and Logging System (RMLS) database and the Aviation System Performance Metrics (ASPM) databases to identify lightning-induced outages, and connect them with weather conditions, demand and landing runway to calculate the total delays induced by the outages, as well as the number of cancellations and diversions. The costs are then determined by calculating direct costs to aircraft operators and costs of passengers' time for delays, cancellations and diversions. The results indicate that 1) not all NAVAIDS are created equal, and 2) outside conditions matter. The cost of an outage depends on the importance of the failed system and the conditions that prevailed before, during and after the failure. The outage that occurs during high demand and poor weather conditions is more likely to result in more delays and higher costs.

  15. Use of workstations in the ANAV outage tasks course access; Utilización de estaciones de trabajo en el curso de acceso de recargas de ANAV

    Energy Technology Data Exchange (ETDEWEB)

    Gómez Rodriguez, Carlos A.

    2016-07-01

    The access course for the Asco and Vandellos II Nuclear Power Plants contains all of the training that is considered necessary in compliance with the stipulations of current legislation for the pupils to carry out their activity at the plants. Given the heterogeneity of the special characteristics of those workers who take part in the outage tasks at our plants we have sought to improve the learning values of their access course with the inclusion of Work Stations since 2013. Several changes have been made in the training action since that date to make it more interactive.

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

    KAUST Repository

    Benjillali, Mustapha; Alouini, Mohamed-Slim

    2010-01-01

    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

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

    KAUST Repository

    Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

    2015-01-01

    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

  18. Assessment of productivity at four generating plants

    International Nuclear Information System (INIS)

    Saarlas, M.; Nelson, M.

    1976-01-01

    The 1975 FEA study of power plant reliability was undertaken as a first step in improving the productivity of large (larger than 400 MW) generating units by attempting to trace outages to their root causes so that meaningful corrective action can be taken at the root of the problem. Trident Engineering Associates studied the operation, maintenance, management, and manning of two fossil-fueled and two nuclear-fueled units, one each of above average and one below average reliability (high availability and low forced outage rate). It was expected that the differences between a highly reliable unit and a less reliable unit would lead to recommendations which would be useful for improving productivity of units throughout the country. The findings are of two basic types: (1) general concepts covering problem areas, fundamental reasons and immediate symptoms behind the problems, methods used to eliminate or alleviate the problems, and proposed solutions; (2) details which provide statistics that establish the relative lost productivity by fundamental causes. Eight root causes (fundamental reasons for failures or outages) were established into which most failures and outages could be assigned. Twenty nine cause factors (causes of failure) were established which assisted in assigning the failures and outages to a root cause

  19. Complexity and availability for fusion power plants: The potential advantages of inertial fusion energy

    International Nuclear Information System (INIS)

    Perkins, L.J.

    1997-01-01

    Probably the single largest advantage of the inertial route to fusion energy (IFE) is the perception that its power plant embodiments could achieve acceptable capacity factors. This is a result of its relative simplicity, the decoupling of the driver and reactor chamber, and the potential to employ thick liquid walls. The author examines these issues in terms of the complexity, reliability, maintainability and, therefore, availability of both magnetic and inertial fusion power plants and compares these factors with corresponding scheduled and unscheduled outage data from present day fission experience. The author stresses that, given the simple nature of a fission core, the vast majority of unplanned outages in fission plants are due to failures outside the reactor vessel itself. Given one must be prepared for similar outages in the analogous plant external to a fusion power core, this puts severe demands on the reliability required of the fusion core itself. The author indicates that such requirements can probably be met for IFE plants. He recommends that this advantage be promoted by performing a quantitative reliability and availability study for a representative IFE power plant and suggests that databases are probably adequate for this task. 40 refs., 4 figs., 3 tabs

  20. TVA coal-gasification commercial demonstration plant project. Volume 5. Plant based on Koppers-Totzek gasifier. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    This volume presents a technical description of a coal gasification plant, based on Koppers-Totzek gasifiers, producing a medium Btu fuel gas product. Foster Wheeler carried out a conceptual design and cost estimate of a nominal 20,000 TPSD plant based on TVA design criteria and information supplied by Krupp-Koppers concerning the Koppers-Totzek coal gasification process. Technical description of the design is given in this volume.

  1. 10 CFR 501.191 - Use of natural gas or petroleum for certain unanticipated equipment outages and emergencies...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Use of natural gas or petroleum for certain unanticipated... Natural Gas or Petroleum for Emergency and Unanticipated Equipment Outage Purposes § 501.191 Use of natural gas or petroleum for certain unanticipated equipment outages and emergencies defined in section...

  2. Operation of Finnish nuclear power plants. Quarterly report 3rd, quarter 1995

    International Nuclear Information System (INIS)

    Sillanpaeae, T.

    1996-05-01

    Quarterly Reports on the operation of Finnish nuclear power plants describe events and observations relating to nuclear and radiation safety which the Finnish Centre for Radiation and Nuclear Safety (STUK) considers safety significant. Safety improvements at the plants are also described. The Report includes a summary of the radiation safety of plant personnel and of the environment and tabulated data on the plants' production and load factors. Except for the annual maintenance outages of Loviisa plant units and for TVO II's brief outage to repair a failed component, Finnish nuclear power plant units were in power operation in the third quarter of 1995. The load factor average of all plant units was 90.4 %. Events in this quarter were level 0 on the INES scale. Occupational doses and radioactive releases off-site were below authorised limits. Radioactive substances were measurable in samples collected around the plants in such quantities only as have no bearing on the radiation exposure of the population. (orig.) (4 figs., 4 tabs.)

  3. Operation of Finnish nuclear power plants. Quarterly report 3rd, quarter 1995

    Energy Technology Data Exchange (ETDEWEB)

    Sillanpaeae, T [ed.

    1996-05-01

    Quarterly Reports on the operation of Finnish nuclear power plants describe events and observations relating to nuclear and radiation safety which the Finnish Centre for Radiation and Nuclear Safety (STUK) considers safety significant. Safety improvements at the plants are also described. The Report includes a summary of the radiation safety of plant personnel and of the environment and tabulated data on the plants` production and load factors. Except for the annual maintenance outages of Loviisa plant units and for TVO II`s brief outage to repair a failed component, Finnish nuclear power plant units were in power operation in the third quarter of 1995. The load factor average of all plant units was 90.4 %. Events in this quarter were level 0 on the INES scale. Occupational doses and radioactive releases off-site were below authorised limits. Radioactive substances were measurable in samples collected around the plants in such quantities only as have no bearing on the radiation exposure of the population. (orig.) (4 figs., 4 tabs.).

  4. Outage Probability Analysis in Power-Beacon Assisted Energy Harvesting Cognitive Relay Wireless Networks

    Directory of Open Access Journals (Sweden)

    Ngoc Phuc Le

    2017-01-01

    Full Text Available We study the performance of the secondary relay system in a power-beacon (PB assisted energy harvesting cognitive relay wireless network. In our system model, a secondary source node and a relay node first harvest energy from distributed PBs. Then, the source node transmits its data to the destination node with the help of the relay node. Also, fading coefficients of the links from the PBs to the source node and relay node are assumed independent but not necessarily identically distributed (i.n.i.d Nakagami-m random variables. We derive exact expressions for the power outage probability and the channel outage probability. Based on that, we analyze the total outage probability of the secondary relay system. Asymptotic analysis is also performed, which provides insights into the system behavior. Moreover, we evaluate impacts of the primary network on the performance of the secondary network with respect to the tolerant interference threshold at the primary receiver as well as the interference introduced by the primary transmitter at the secondary source and relay nodes. Simulation results are provided to validate the analysis.

  5. Status of the steam generator tube circumferential ODSCC degradation experienced at the Doel 4 plant

    International Nuclear Information System (INIS)

    Roussel, G.

    1997-01-01

    Since the 1991 outage, the Doel Unit 4 nuclear power plant is known to be affected by circumferential outside diameter intergranular stress corrosion cracking at the hot leg tube expansion transition. Extensive non destructive examination inspections have shown the number of tubes affected by this problem as well as the size of the cracks to have been increasing for the three cycles up to 1993. As a result of the high percentage of tubes found non acceptable for continued service after the 1993 in-service inspection, about 1,700 mechanical sleeves were installed in the steam generators. During the 1994 outage, all the tubes sleeved during the 1993 outage were considered as potentially cracked to some extent at the upper hydraulic transition and were therefore not acceptable for continued service. They were subsequently repaired by laser welding. Furthermore all the tubes not sleeved during the 1993 outage were considered as not acceptable for continued service and were repaired by installing laser welded sleeves. During the 1995 outage, some unexpected degradation phenomena were evidenced in the sleeved tubes. This paper summarizes the status of the circumferential ODSCC experienced in the SG tubes of the Doel 4 plant as well as the other connected degradation phenomena

  6. Worldwide nuclear-plant performance

    International Nuclear Information System (INIS)

    Surrey, J.; Thomas, S.

    1980-01-01

    The authors compare the performance of different reactor systems to identify the determinants of plant performance, to examine the evidence of technological maturation, and to discover the principal causes of outage or unavailability. In the light of the findings, they discuss the implications for the UK regarding reactor choice and technology development. They make no judgements about the relative merits of nuclear and fossil-fuel plants, or about safety. (author)

  7. Nuclear power. Volume 1. Nuclear power plant design

    International Nuclear Information System (INIS)

    Pedersen, E.S.

    1978-01-01

    NUCLEAR POWER PLANT DESIGN is intended to be used as a working reference book for management, engineers and designers, and as a graduate-level text for engineering students. The book is designed to combine theory with practical nuclear power engineering and design experience, and to give the reader an up-to-date view of the status of nuclear power and a basic understanding of how nuclear power plants function. Volume 1 contains the following chapters; (1) nuclear reactor theory; (2) nuclear reactor design; (3) types of nuclear power plants; (4) licensing requirements; (5) shielding and personnel exposure; (6) containment and structural design; (7) main steam and turbine cycles; (8) plant electrical system; (9) plant instrumentation and control systems; (10) radioactive waste disposal (waste management) and (11) conclusion

  8. Standard technical specifications: Combustion engineering plants. Volume 1, Revision 1: Specifications

    International Nuclear Information System (INIS)

    1995-04-01

    This report documents the results of the combined effort of the NRC and the industry to produce improved Standard Technical Specifications (STS), Revision 1 for Combustion Engineering Plants. The changes reflected in Revision 1 resulted from the experience gained from license amendment applications to convert to these improved STS or to adopt partial improvements to existing technical specifications. This NUREG is the result of extensive public technical meetings and discussions between the Nuclear Regulatory Commission (NRC) staff and various nuclear power plant licensees, Nuclear Steam Supply System (NSSS) Owners Groups, NSSS vendors, and the Nuclear Energy Institute (NEI). The improved STS were developed based on the criteria in the Final Commission Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors, dated July 22, 1993. The improved STS will be used as the basis for individual nuclear power plant licensees to develop improved plant-specific technical specifications. This report contains three volumes. Volume 1 contains the Specifications for all chapters and sections of the improved STS. Volume 2 contains the Bases for Chapters 2.0 and 3.0, and Sections 3.1--3.3 of the improved STS. Volume 3 contains the Bases for Sections 3.4--3.9 of the improved STS

  9. 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.

  10. Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 2. Appendices

    International Nuclear Information System (INIS)

    1977-09-01

    Volume 2 is comprised of appendices: Portsmouth Gaseous Diffusion Plant Existing Facilities; Ecology; Civic Involvement; Social Analysis; Population Projections; Toxicity of Air Pollutants to Biota at Portsmouth Gaseous Diffusion Plant; and Assessment of Noise Effects of an Add-On to the Portsmouth Gaseous Diffusion Plant

  11. Outage probability analysis of a secondary user in an underlay dual hop cognitive amplify and forward relay network

    Directory of Open Access Journals (Sweden)

    Kiran Chandra

    2016-09-01

    Full Text Available This paper presents the performance evaluation of a secondary user (SU in an underlay cognitive dual-hop relaying system considering instantaneous as well as average channel information of the interfering links (from the secondary source and relay to the primary receiver and the data link from the secondary source to relay, to calculate transmit power and amplifying gain of secondary system. Comparison of above mentioned cases is done for two different scenarios – with direct path and without direct path. We evaluate the performance considering two different diversity techniques namely as selection combining (SC and maximum ratio combining (MRC. The effect of different fading channels (Rayleigh and Nakagami on the outage performance of the SU for the two diversity techniques is also shown. The outage probability of the SU is reduced when the diversity techniques are used (with direct path as compared to the outage probability of SU without direct path. We find that the outage performance is better for instantaneous channel information as compared to average channel information for the links. We observe that MRC provides better performance than SC. Furthermore, this work shows that the outage performance of the SU has been improved when the Nakagami fading channel (m = 2 is considered instead of Rayleigh fading channel.

  12. Dose reduction and cost-benefit analysis at Japan's Tokai No. 2 Plant

    International Nuclear Information System (INIS)

    Humamoto, Hisao; Suzuki, Seishiro; Taniguchi, Kazufumi

    1995-01-01

    In the Tokai No. 2 power plant of the Japan Atomic Power Company, about 80% of the annual dose equivalent is received during periodic maintenance outages. A project group for dose reduction was organized at the company's headquarters in 1986; in 1988, they proposed a five-year program to reduce by half the collective dose of 4 person-Sv per normal outage work. To achieve the target dose value, some dose-reduction measures were undertaken, namely, permanent radiation shielding, decontamination, automatic, operating machines, and ALARA organization. As the result, the collective dose from normal outage work was 1.6 person-Sv in 1992, which was less than the initial target value

  13. Preliminary design of the Carrisa Plains solar central receiver power plant. Volume II. Plant specifications

    Energy Technology Data Exchange (ETDEWEB)

    Price, R. E.

    1983-12-31

    The specifications and design criteria for all plant systems and subsystems used in developing the preliminary design of Carrisa Plains 30-MWe Solar Plant are contained in this volume. The specifications have been organized according to plant systems and levels. The levels are arranged in tiers. Starting at the top tier and proceeding down, the specification levels are the plant, system, subsystem, components, and fabrication. A tab number, listed in the index, has been assigned each document to facilitate document location.

  14. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Summary of results. Volume 1

    International Nuclear Information System (INIS)

    Whitehead, D.W.; Staple, B.D.; Daniel, S.L.

    1995-07-01

    During 1989 the Nuclear Regulatory Commission (NRC) initiated an extensive program to examine the potential risks during low power and shutdown operations. Two plants, Surry and Grand Gulf, were selected as the plants to be studied by Brookhaven National Laboratory (Surry) and Sandia National Laboratories (Grand Gulf). This report documents the work performed during the analysis of the Grand Gulf plant. A phased approach was used for the overall study. In Phase 1, the objectives were to identify potential vulnerable plant configurations, to characterize (on a high, medium, or low basis) the potential core damage accident scenario frequencies and risks, and to provide a foundation for a detailed Phase 2 analysis. It was in Phase 1 that the concept of plant operational states (POSs) was developed to allow the analysts to better represent the plant as it transitions from power operation to nonpower operation than was possible with the traditional technical specification divisions of modes of operation. This phase consisted of a coarse screening analysis performed for all POSs, including seismic and internal fire and flood for some POSs. In Phase 2, POS 5 (approximately cold shutdown as defined by Grand Gulf Technical Specifications) during a refueling outage was selected as the plant configuration to be analyzed based on the results of the Phase 1 study. The scope of the Level 1 study includes plant damage state analysis and uncertainty analysis and is documented in a multi-volume NUREG/CR report (i.e., NUREG/CR-6143). The internal events analysis is documented in Volume 2. Internal fire and internal flood analyses are documented in Volumes 3 and 4, respectively. A separate study on seismic analysis, documented in Volume 5, was performed for the NRC by Future Resources Associates, Inc. The Level 2/3 study of the traditional internal events is documented in Volume 6, and a summary of the results for all analyses is documented in Volume 1

  15. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Summary of results. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, D.W. [ed.; Staple, B.D.; Daniel, S.L. [and others

    1995-07-01

    During 1989 the Nuclear Regulatory Commission (NRC) initiated an extensive program to examine the potential risks during low power and shutdown operations. Two plants, Surry and Grand Gulf, were selected as the plants to be studied by Brookhaven National Laboratory (Surry) and Sandia National Laboratories (Grand Gulf). This report documents the work performed during the analysis of the Grand Gulf plant. A phased approach was used for the overall study. In Phase 1, the objectives were to identify potential vulnerable plant configurations, to characterize (on a high, medium, or low basis) the potential core damage accident scenario frequencies and risks, and to provide a foundation for a detailed Phase 2 analysis. It was in Phase 1 that the concept of plant operational states (POSs) was developed to allow the analysts to better represent the plant as it transitions from power operation to nonpower operation than was possible with the traditional technical specification divisions of modes of operation. This phase consisted of a coarse screening analysis performed for all POSs, including seismic and internal fire and flood for some POSs. In Phase 2, POS 5 (approximately cold shutdown as defined by Grand Gulf Technical Specifications) during a refueling outage was selected as the plant configuration to be analyzed based on the results of the Phase 1 study. The scope of the Level 1 study includes plant damage state analysis and uncertainty analysis and is documented in a multi-volume NUREG/CR report (i.e., NUREG/CR-6143). The internal events analysis is documented in Volume 2. Internal fire and internal flood analyses are documented in Volumes 3 and 4, respectively. A separate study on seismic analysis, documented in Volume 5, was performed for the NRC by Future Resources Associates, Inc. The Level 2/3 study of the traditional internal events is documented in Volume 6, and a summary of the results for all analyses is documented in Volume 1.

  16. Phase I: the pipeline-gas demonstration plant. Demonstration plant engineering and design. Volume 18. Plant Section 2700 - Waste Water Treatment

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-05-01

    Contract No. EF-77-C-01-2542 between Conoco Inc. and the US Department of Energy provides for the design, construction, and operation of a demonstration plant capable of processing bituminous caking coals into clean pipeline quality gas. The project is currently in the design phase (Phase I). This phase is scheduled to be completed in June 1981. One of the major efforts of Phase I is the process and project engineering design of the Demonstration Plant. The design has been completed and is being reported in 24 volumes. This is Volume 18 which reports the design of Plant Section 2700 - Waste Water Treatment. The objective of the Waste Water Treatment system is to collect and treat all plant liquid effluent streams. The system is designed to permit recycle and reuse of the treated waste water. Plant Section 2700 is composed of primary, secondary, and tertiary waste water treatment methods plus an evaporation system which eliminates liquid discharge from the plant. The Waste Water Treatment Section is designed to produce 130 pounds per hour of sludge that is buried in a landfill on the plant site. The evaporated water is condensed and provides a portion of the make-up water to Plant Section 2400 - Cooling Water.

  17. Operation of Finnish nuclear power plants

    International Nuclear Information System (INIS)

    Tossavainen, K.

    1994-03-01

    In the third quarter of 1993, all of Finland's four nuclear power plant units were in power operation, with the exception of the annual maintenance outages of the Loviisa units. The load factor average of the plant units was 83.6 %. None of the events which occurred during this annual quarter had any bearing on nuclear or radiation safety. (4 figs., 5 tabs.)

  18. A Business Case for Nuclear Plant Control Room Modernization

    International Nuclear Information System (INIS)

    Thomas, Ken; Lawrie, Sean; Niedermuller, Josef M.

    2016-01-01

    This paper presents a generic business case for implementation of technology that supports Control Room Modernization (CRM). The analysis presented in two forms; 1) a standalone technology upgrade, and 2) a technology upgrade that is built upon and incremental to a prior business case created for Mobile Work Packages (MWP). The business case contends that advanced communication and networking and analytical technologies will allow NPP to conduct control room operations with improved focus by reducing human factors and redundant manpower, and therefore operate with fewer errors. While some labor savings can be harvested in terms of overtime, the majority of savings are demonstrated as reduced time to take the plant off line and bring back on line in support of outages. The benefits are quantified to a rough order of magnitude that provides directional guidance to NPPs that are interested in developing a similar business case. This business case focuses on modernization of the operator control room and does not consider a complete overhaul and modernization of a plants instrument and control systems. While operators may be considering such an investment at their plants, the sizable capital investment required is not likely supported by a cost/benefit analysis alone. More likely, it is driven by obsolescence and reliability issues, and requires consideration of mechanical condition of plant systems, capital depreciation, financing, relicensing and overall viability of the plant asset over a 20-year horizon in a competitive market. Prior studies [REF] have indicated that such a modernization of plant I&C systems, alone or as part of a larger modernization effort, can yield very significant reductions in O&M costs. However, the depth of research and analysis required to develop a meaningful business case for a plant modernization effort is well beyond the scope of this study. While CRM as considered in this study can be easily integrated as part of grander plant

  19. A Business Case for Nuclear Plant Control Room Modernization

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Ken [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lawrie, Sean [Idaho National Lab. (INL), Idaho Falls, ID (United States); Niedermuller, Josef M. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-06-01

    This paper presents a generic business case for implementation of technology that supports Control Room Modernization (CRM). The analysis presented in two forms; 1) a standalone technology upgrade, and 2) a technology upgrade that is built upon and incremental to a prior business case created for Mobile Work Packages (MWP). The business case contends that advanced communication and networking and analytical technologies will allow NPP to conduct control room operations with improved focus by reducing human factors and redundant manpower, and therefore operate with fewer errors. While some labor savings can be harvested in terms of overtime, the majority of savings are demonstrated as reduced time to take the plant off line and bring back on line in support of outages. The benefits are quantified to a rough order of magnitude that provides directional guidance to NPPs that are interested in developing a similar business case. This business case focuses on modernization of the operator control room and does not consider a complete overhaul and modernization of a plants instrument and control systems. While operators may be considering such an investment at their plants, the sizable capital investment required is not likely supported by a cost/benefit analysis alone. More likely, it is driven by obsolescence and reliability issues, and requires consideration of mechanical condition of plant systems, capital depreciation, financing, relicensing and overall viability of the plant asset over a 20-year horizon in a competitive market. Prior studies [REF] have indicated that such a modernization of plant I&C systems, alone or as part of a larger modernization effort, can yield very significant reductions in O&M costs. However, the depth of research and analysis required to develop a meaningful business case for a plant modernization effort is well beyond the scope of this study. While CRM as considered in this study can be easily integrated as part of grander plant

  20. Efficient Simulation of the Outage Probability of Multihop Systems

    KAUST Repository

    Ben Issaid, Chaouki; Alouini, Mohamed-Slim; Tempone, Raul

    2017-01-01

    In this paper, we present an efficient importance sampling estimator for the evaluation of the outage probability of multihop systems with amplify-and-forward channel state-information-assisted. The proposed estimator is endowed with the bounded relative error property. Simulation results show a significant reduction in terms of number of simulation runs compared to naive Monte Carlo.

  1. Efficient Simulation of the Outage Probability of Multihop Systems

    KAUST Repository

    Ben Issaid, Chaouki

    2017-10-23

    In this paper, we present an efficient importance sampling estimator for the evaluation of the outage probability of multihop systems with amplify-and-forward channel state-information-assisted. The proposed estimator is endowed with the bounded relative error property. Simulation results show a significant reduction in terms of number of simulation runs compared to naive Monte Carlo.

  2. Engineerig of structural modifications for operating nuclear plants

    International Nuclear Information System (INIS)

    Duffy, T.J.; Gazda, P.A.

    1983-01-01

    The engineering of structural modifications for operating nuclear plants offers many challenges in the areas of scheduling of work, field adjustments, and engineering staff planning. The scheduling of structural modification work for operating nuclear plants is normally closely tied to planned or unplanned outages of the plant. Coordination between the structural engineering effort, the operating plant staff, and the contractor who will be performing the modifications is essential to ensure that all work can be completed within the allotted time. Due to the inaccessibility of areas in operating plants or the short time available to perform the structural engineering in the case of an unscheduled outage, field verification of a design is not always possible prior to initiating the construction of the modification. This requires the structural engineer to work closely with the contractor to promptly resolve problems due to unanticipated interferences or material procurement that may arise during the course of construction. The engineering staff planning for structural modifications at an operating nuclear plant must be flexible enough to permit rapid response to the common 'fire drills', but controlled enough to assure technically correct designs and minimize the expenditure of man-hours and resulting engineering cost. (orig.)

  3. Outages of electric power supply resulting from cable failures Boston Edison Company system

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-07-01

    Factual data are provided regarding 5 electric power supply interruptions that occurred in the Boston Metropolitan area during April to June, 1979. Common to all of these outages was the failure of an underground cable as the initiating event, followed by multiple equipment failures. There was significant variation in the voltage ratings and types of cables which failed. The investigation was unable to delineate a single specific Boston Edison design operating or maintenance practice that could be cited as the cause of the outages. After reviewing the investigative report the following actions were recommended: the development and implementation of a plan to eliminate the direct current cable network; develop a network outage restoration plan; regroup primary feeder cables wherever possible to minimize the number of circuits in manholes, and to separate feeders to high load density areas; develop a program to detect incipient cable faults; evaluate the separation of the north and south sections of Back Bay network into separate networks; and, as a minimum, install the necessary facilities to make it possible to re-energize one section without interfering with the other; and re-evaluate the cathodic protection scheme where necessary. (LCL)

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

    KAUST Repository

    Ansari, Imran Shafique; Abdallah, Mohamed M.; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

    2014-01-01

    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

  5. Information needs in nuclear power plants during low power operation modes

    Energy Technology Data Exchange (ETDEWEB)

    Tommila, Teemu; Fantoni, Paolo F.; Zander, Ralf M.

    1998-02-01

    During the past few years an increasing attention has been paid to the safety of shutdown and refuelling operations. It has turned out that the risks during shutdown may be comparable to the risks of power operation. The goal of this report is to identify information requirements related to low power operating modes of nuclear power plants. These include, for example, warm and cold shutdowns, refuelling and maintenance, as well as related state transitions such as start-up and shut-down. The focus of the report is on planned refuelling outages and the role of the control room in managing the outage activities. As a starting point, the basic terminology and characteristics of low power operation are discussed. The current situation at nuclear power plants and some recent developments in information technology are reviewed. End-users' requirements and enabling technologies are combined in order to identify the opportunities for new information technology tools in low power operation. The required features of process control systems and maintenance information systems are described. Common plant modelling techniques, open software architectures and functional structuring of the process control system are suggested to be the key issues in the long-term development of operator support systems. On a shorter time scale, new tools solving limited practical problems should be developed and evaluated. This would provide a basis for the features needed for low power operation, including for example, outage planning, on-line risk monitoring, management of outage tasks, adaptive alarm handling, computerised procedures and task-oriented human interfaces. (author)

  6. Investigation on cause of outage of Wide Range Monitor (WRM) in High Temperature engineering Test Reactor (HTTR). Transport operation toward investigation for cause of outage

    International Nuclear Information System (INIS)

    Shinohara, Masanori; Sawahata, Hiroaki; Kawamoto, Taiki; Saito, Kenji; Takada, Shoji; Yoshida, Naoaki; Isozaki, Ryosuke; Katsuyama, Kozo; Motegi, Toshihiro

    2012-08-01

    An event, in which one of WRMs were disabled to detect the neutron flux in the reactor core, occurred during the period of reactor shut down of HTTR in March, 2010. The actual life time of WRM was unexpectedly shorter than the past developed life time. Investigation of the cause of the outage of WRM toward the recovery of the life time up to the developed life is one of the issues to develop the technology basis of High Temperature Gas cooled Reactor (HTGR). Then, a post irradiation examination was planned to specify the damaged part causing the event in the WRM was also planned. For the investigation, the X-ray computed tomography scanner in Fuels Monitoring Facility (FMF). This report describes the preliminary investigation on the cause of outage of the WRM. The results of study for transportation method of the irradiated WRM from HTTR to FMF is also reported with the record to complete the transport operation. (author)

  7. A RLS-SVM Aided Fusion Methodology for INS during GPS Outages.

    Science.gov (United States)

    Yao, Yiqing; Xu, Xiaosu

    2017-02-24

    In order to maintain a relatively high accuracy of navigation performance during global positioning system (GPS) outages, a novel robust least squares support vector machine (LS-SVM)-aided fusion methodology is explored to provide the pseudo-GPS position information for the inertial navigation system (INS). The relationship between the yaw, specific force, velocity, and the position increment is modeled. Rather than share the same weight in the traditional LS-SVM, the proposed algorithm allocates various weights for different data, which makes the system immune to the outliers. Field test data was collected to evaluate the proposed algorithm. The comparison results indicate that the proposed algorithm can effectively provide position corrections for standalone INS during the 300 s GPS outage, which outperforms the traditional LS-SVM method. Historical information is also involved to better represent the vehicle dynamics.

  8. A RLS-SVM Aided Fusion Methodology for INS during GPS Outages

    Directory of Open Access Journals (Sweden)

    Yiqing Yao

    2017-02-01

    Full Text Available In order to maintain a relatively high accuracy of navigation performance during global positioning system (GPS outages, a novel robust least squares support vector machine (LS-SVM-aided fusion methodology is explored to provide the pseudo-GPS position information for the inertial navigation system (INS. The relationship between the yaw, specific force, velocity, and the position increment is modeled. Rather than share the same weight in the traditional LS-SVM, the proposed algorithm allocates various weights for different data, which makes the system immune to the outliers. Field test data was collected to evaluate the proposed algorithm. The comparison results indicate that the proposed algorithm can effectively provide position corrections for standalone INS during the 300 s GPS outage, which outperforms the traditional LS-SVM method. Historical information is also involved to better represent the vehicle dynamics.

  9. 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.

  10. Outage Performance of Hybrid FSO/RF System with Low-Complexity Power Adaptation

    KAUST Repository

    Rakia, Tamer

    2016-02-26

    Hybrid free-space optical (FSO) / radio-frequency (RF) systems have emerged as a promising solution for high data- rate wireless communication systems. We consider truncated channel inversion based power adaptation strategy for coherent and non- coherent hybrid FSO/RF systems, employing an adaptive combining scheme. Specifically, we activate the RF link along with the FSO link when FSO link quality is unacceptable, and adaptively set RF transmission power to ensure constant combined signal-to-noise ratio at receiver terminal. Analytical expressions for the outage probability of the hybrid system with and without power adaptation are derived. Numerical examples show that, the hybrid FSO/RF systems with power adaptation achieve considerable outage performance improvement over conventional hybrid FSO/RF systems without power adaptation. © 2015 IEEE.

  11. Radio resource management scheme and outage analysis for network-assisted multi-hop D2D communications

    Directory of Open Access Journals (Sweden)

    Leila Melki

    2016-11-01

    Full Text Available In a cellular network it's very difficult to make spectrum resource more efficiently. Device-to-Device (D2D technology enables new service opportunities, and provides high throughput and reliable communication while reducing the base station load. For better total performance, short-range D2D links and cellular links share the same radio resource and the management of interference becomes a crucial task. Here we argue that single-hop D2D technology can be used to further improve cellular networks performance if the key D2D radio resource management algorithms are suitably extended to support multi-hop D2D communications. Aiming to establish a new paradigm for the analysis and design of multi-hop D2D communications, We propose a radio resource allocation for multi-hop D2D routes based on interference avoidance approach in LTE-A networks. On top of that, we investigate the outage probability of D2D communication. We first introduce a new definition of outage probability by considering the maximum distance to be allowable for single-hop transmission. Then we study and analyze the outage performance of a multi-hop D2D route. We derive the general closed form expression of outage probability of the multi-hop D2D routes. The results demonstrate that the D2D radio, sharing the same resources as the cellular network, provide higher capacity compared to pure cellular communication where all the data is transmitted through the base station. They also demonstrate that the new method of calculation of D2D multi hop outage probability has better performance than classical method defined in the literature.

  12. Performance Analysis of Secrecy Outage Probability for AF-Based Partial Relay Selection with Outdated Channel Estimates

    Directory of Open Access Journals (Sweden)

    Kyu-Sung Hwang

    2017-01-01

    Full Text Available We study the secrecy outage probability of the amplify-and-forward (AF relaying protocol, which consists of one source, one destination, multiple relays, and multiple eavesdroppers. In this system, the aim is to transmit the confidential messages from a source to a destination via the selected relay in presence of eavesdroppers. Moreover, partial relay selection scheme is utilized for relay selection based on outdated channel state information where only neighboring channel information (source-relays is available and passive eavesdroppers are considered where a transmitter does not have any knowledge of eavesdroppers’ channels. Specifically, we offer the exact secrecy outage probability of the proposed system in a one-integral form as well as providing the asymptotic secrecy outage probability in a closed-form. Numerical examples are given to verify our provided analytical results for different system conditions.

  13. Operation of Finnish nuclear power plants. Quarterly report, 2nd quarter, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Tossavainen, K. [ed.

    1995-10-01

    Quarterly reports on the operation of Finnish nuclear power plants describe events and observations relating to nuclear and radiation safety which the Finnish Centre for Radiation and Nuclear Safety (STUK) considers safety significant. Fasety improvements at the plants are also described. The report includes a summary of the radiation safety of plant personnel and of the evironment and tabulated data on the plants` production and load factors. Except for the annual maintenance outages of the TVO plant units and for TVO II`s Midsummer outage which was due to low electricity demand, the Finnish nuclear power plants were in power operation during the second quarter of 1995. The load factor average of all four plant units was 91.2 %. Events during the second annual quarter were level 0 on the INES scale. Occupational doses and radioactive releases off-site were below authorized limits. Radioactive substances were measurable in samples collected around the plants in such quantities only as have no bearing on the radiation exposure of the population. (4 figs., 4 tabs.).

  14. Standard technical specifications General Electric plants, BWR/6. Volume 1, Revision 1

    International Nuclear Information System (INIS)

    1995-04-01

    This report documents the results of the combined effort of the NRC and the industry to produce improved Standard Technical Specifications (STS), Revision 1 for General Electric BWR/6 Plants. The changes reflected in Revision 1 resulted from the experience gained from license amendment applications to convert to these improved STS or to adopt partial improvements to existing technical specifications. This NUREG is the result of extensive public technical meetings and discussions between the Nuclear Regulatory Commission (NRC) staff and various nuclear power plant licensees, Nuclear Steam Supply System (NSSS) Owners Groups, NSSS vendors, and the Nuclear Energy Institute (NEI). The improved STS were developed based on the criteria in the Final Commission Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors, dated July 22, 1993. The improved STS will be used as the basis for individual nuclear power plant licensees to develop improved plant-specific technical specifications. This report contains three volumes. Volume 1 contains the Specifications for all chapters and sections of the improved STS. Volume 2 contains the Bases for Chapters 2.0 and 3.0, and Sections 3.1--3.3 of the improved STS. Volume 3 contains the Bases for Sections 3.4--3.10 of the improved STS

  15. [Responding to patients with home mechanical ventilation after the Great East Japan Earthquake and during the planned power outages. How should we be prepared for a future disaster ?].

    Science.gov (United States)

    Takechi, Yukako

    2011-12-01

    The unprecedented earthquake(magnitude-9 in the Japanese seismic intensity scale)hit off the east coast of Japan on March 11, 2011. Consequently, there were planned power outages in the area nearby Tokyo to avoid massive blackouts caused by a stoppage of Fukushima nuclear plants.Our clinic located in Kawasaki city was also hit by the earthquake(magnitude- 5).During the period of two months(March and April 2011), we had a total of 52 patients with home respiratory care (5-TPPV, 11-NPPV and 36-HOT)at that time.Two out of three 24 hour-TPPV users had no external battery.After the earthquake, there was a 7-hour electricity failure in some areas, and a patient with ASV(adaptive servo ventilator)was living there.Moreover, 3-hour/day power outages were carried out from March 14 to March 28, affecting people's everyday lives. However, the patient had no harmful influences from the power failure because a ventilation company lent us an external battery(4-9 hour life capacity)for the patients, and we were able to avoid an emergency situation caused by the power failure.In conclusion, we ought to be prepared for patients with home mechanical ventilation in the future toward unforeseen large scale power outages.

  16. Dose reduction and cost-benefit analysis at Japan`s Tokai No. 2 Plant

    Energy Technology Data Exchange (ETDEWEB)

    Humamoto, Hisao; Suzuki, Seishiro; Taniguchi, Kazufumi [Japan Atomic Power Co., Otemachi (Japan)

    1995-03-01

    In the Tokai No. 2 power plant of the Japan Atomic Power Company, about 80% of the annual dose equivalent is received during periodic maintenance outages. A project group for dose reduction was organized at the company`s headquarters in 1986; in 1988, they proposed a five-year program to reduce by half the collective dose of 4 person-Sv per normal outage work. To achieve the target dose value, some dose-reduction measures were undertaken, namely, permanent radiation shielding, decontamination, automatic, operating machines, and ALARA organization. As the result, the collective dose from normal outage work was 1.6 person-Sv in 1992, which was less than the initial target value.

  17. 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.

  18. Planning of occupational dose reduction at BWR power plant by past dose record analysis combined with on-site workers' idea analysis

    International Nuclear Information System (INIS)

    Konno, T.; Taira, J.; Hayashida, T.; Suzuki, A.; Hayashi, K.; Kato, S.; Ishikawa, T.; Konno, T.; Hayashi, K.

    2011-01-01

    In order to establish a plan for occupational dose reduction at operating plants, outage inspection works that involve high-dose exposure were selected and a determination of the major causes of high-dose exposure made by plant-by-plant comparison of doses received during inspection works. The comparison was made to investigate the relationship between exposure and the volume of objects to be inspected, working time and man-hour of each work process and ambient dose rates at work areas. In parallel with this, an analysis has also been carried out on 400 data items in a questionnaire survey conducted on relevant individuals, including foremen, radiation safety personnel, on-site workers and plant designers regarding ideas for dose reduction methods. With combination of these two analyses, matters that require improvement will be highlighted, then modification of equipment or revision of work procedures necessary for occupational dose reduction will be planned by plant designers through review. (authors)

  19. Acoustic valve leak detection in nuclear plants

    International Nuclear Information System (INIS)

    Dimmick, J.G.; Dickey, J.W.

    1983-01-01

    Internal valve leakage is a hidden energy loss and can cause or prolong a forced outage. Recent advances in acoustic detection of internal valve leakage have reduced piping system maintenance costs, unnecessary downtime, and energy waste. Extremely short payback periods have been reported by plants applying this technology to preventive maintenance, troubleshooting, energy conservation and outage planning. Sensors temporarily attached to the outside of valves and connected to the instruments detect ultrasonic acoustic emissions which are characteristic of internal valve leakage. Since the sensors are attached to the outside of the valves, the time and expense of dismantling the valves or removing them from the systems are eliminated. This paper describes the instrumentation and specific applications to nuclear plant valves, including independent verification of initial findings. Guidelines for potential users, including instrumentation selection, training requirements, application planning, and the choice of in-house versus contract services are discussed

  20. 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.

  1. Zero-Outage Cellular Downlink with Fixed-Rate D2D Underlay

    DEFF Research Database (Denmark)

    Kiilerich Pratas, Nuno; Popovski, Petar

    2015-01-01

    . D2D connections can be instrumental in localized aggregation of uplink M2M traffic to a more capable cellular device, before being finally delivered to the Base Station (BS). In this paper we show that a fixed M2M rate is an enabler of efficient Machine-Type D2D underlay operation taking place......, but not the interfering channels from the MTDs to U, we prove that there is a positive downlink rate that can always be decoded by U, leading to zero-outage of the downlink signal. This is a rather surprising consequence of the features of the multiple access channel and the fixed rate RM. We also consider the case...... of a simpler, single-user decoder at U with successive interference cancellation. However, with single-user decoder, a positive zero-outage rate exists only when NM = 1 and is zero when NM > 1. This implies that joint decoding is instrumental in enabling fixed-rate underlay operation....

  2. Survey of fish impingement at power plants in the United States. Volume II. Inland waters

    International Nuclear Information System (INIS)

    Freeman, R.F. III; Sharma, R.K.

    1977-03-01

    Impingement of fish at cooling-water intakes of 33 power plants located on inland waters other than the Great Lakes has been surveyed and data are presented. Descriptions of site, plant, and intake design and operation are provided. Reports in this volume summarize impingement data for individual plants in tabular and histogram formats. Information was available from differing sources such as the utilities themselves, public documents, regulatory agencies, and others. Thus, the extent of detail in the reports varies greatly from plant to plant. Histogram preparation involved an extrapolation procedure that has inadequacies. The reader is cautioned in the use of information presented in this volume to determine intake-design acceptability or intensity of impacts on ecosystems. No conclusions are presented herein; data comparisons are made in Volume IV

  3. 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.

  4. Use of nondestructive evaluation methods to improve power plant availability

    International Nuclear Information System (INIS)

    Weber, R.M.

    1985-01-01

    On an ever-increasing basis, utilities are relying on nondestructive evaluation (NDE) as a management and planning tool. In addition to the conventional ASME Code and Technical Specification-required examinations, progressive utilities are utilizing NDE sampling programs to monitor existing conditions and search for potential situations affecting plant safety and reliability. Improved NDE detection and sizing procedures give management personnel the accurate information needed to make the ''go/no go'' decisions on repair programs which can significantly affect plant availability. As the burden of regulatory-imposed inspection requirements increases, plant personnel are increasingly cognizant that NDE is a significant factor in their plant's outage schedule. Whether an outage is scheduled or forced, NDE becomes part of each plant's program to assure the safety and reliability of its critical components. Knowledge and planning of NDE application is important because of the time expended in examination performance and subsequent data evaluation. Managers who are knowledgeable in NDE application can effectively improve plant availability by scheduling NDE as an integral part of their maintenance programs. Examination results can then be used in making decisions directly affecting availability

  5. 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.

  6. 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)

  7. The spill prevention, control, and countermeasures (SPCC) plan for the Y-12 Plant. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    This spill prevention, control and countermeasures (SPCC) Plan is divided into two volumes. Volume I addresses Y-12`s compliance with regulations pertinent to the content of SPCC Plans. Volume II is the SPCC Hazardous Material Storage Data Base, a detailed tabulation of facility-specific information and data on potential spill sources at the Y-12 Plant. Volume I follows the basic format and subject sequence specified in 40 CFR 112.7. This sequence is prefaced by three additional chapters, including this introduction and brief discussions of the Y-12 Plant`s background/environmental setting and potential spill source categories. Two additional chapters on containers and container storage areas and PCB and PCB storage for disposal facilities are inserted into the required sequence. The following required subjects are covered in this volume: Spill history, site drainage; secondary containment/diversion structures and equipment; contingency plans; notification and spill response procedures; facility drainage; bulk storage tanks; facility transfer operations, pumping, and in-plant processes; transfer stations (facility tank cars/tank tracks); inspections and records; security, and personnel, training, and spill prevention procedures.

  8. 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.

  9. A study on assessment methodology of surveillance test interval and Allowed Outage Time

    International Nuclear Information System (INIS)

    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

    1997-07-01

    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

  10. Reliability of the Solar One plant during the power production phase: August 1, 1984--July 31, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, G.J.; Lopez, C.W.

    1988-10-01

    The power production phase at Solar One spanned three years from August 1, 1984 through July 31, 1987. In that period the plant achieved an average availability, during hours of sunshine, of 81.7%. This report presents the frequencies and causes of the plant outages that occurred. The eleven most important causes composed 75% of the total outage time. Qualitative insights related to the origin and mitigation of these causes are provided. Also presented are insights and statistics regarding the reliability of the heliostat field. The quantitative and qualitative information presented in this report will be useful to studies aimed at improving the reliability of future solar central receiver power plants. 20 refs., 11 figs., 3 tabs.

  11. 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.

  12. Modernization of Kozloduy nuclear plant unit 5 and 6, implementation of measures to improve the reliability of the main generator system

    International Nuclear Information System (INIS)

    Stinshoff, H.

    2003-01-01

    To improve the reliability of Kozloduy Nuclear power plant several modernization measures will be implemented during the outages in the years 2003 to 2005. In the area of the main generator the following measures will be performed in unit 6 during 2003 outage: - Replacement of main generator circuit breaker by new SF6 cooled breaker type - Replacement of main generator excitation system by new two channel digital system - Replacement of main generator protection by new digital multi-purpose protections including digital fault recorders - Installation of radio frequency monitoring system of main generator circuit Starting from the present situation the new concept is explained. The project organization under consideration of large Bulgarian participation as well as the sequence and schedule of the implementation during the short outage time window is shown. These modernization measures lead to an increase of reliability and availability for the operation of the power plant and with this to increase power plant safety

  13. Improving allowed outage time and surveillance test interval requirements: a study of their interactions using probabilistic methods

    International Nuclear Information System (INIS)

    Martorell, S.A.; Serradell, V.G.; Samanta, P.K.

    1995-01-01

    Technical Specifications (TS) define the limits and conditions for operating nuclear plants safely. We selected the Limiting Conditions for Operations (LCO) and Surveillance Requirements (SR), both within TS, as the main items to be evaluated using probabilistic methods. In particular, we focused on the Allowed Outage Time (AOT) and Surveillance Test Interval (STI) requirements in LCO and SR, respectively. Already, significant operating and design experience has accumulated revealing several problems which require modifications in some TS rules. Developments in Probabilistic Safety Assessment (PSA) allow the evaluation of effects due to such modifications in AOT and STI from a risk point of view. Thus, some changes have already been adopted in some plants. However, the combined effect of several changes in AOT and STI, i.e. through their interactions, is not addressed. This paper presents a methodology which encompasses, along with the definition of AOT and STI interactions, the quantification of interactions in terms of risk using PSA methods, an approach for evaluating simultaneous AOT and STI modifications, and an assessment of strategies for giving flexibility to plant operation through simultaneous changes on AOT and STI using trade-off-based risk criteria

  14. Standard technical specifications: General Electric plants, BWR/4. Volume 1, Revision 1: Specifications

    International Nuclear Information System (INIS)

    1995-04-01

    This report documents the results of the combined effort of the NRC and the industry to produce improved Standard Technical Specifications (STS), Revision 1 for General Electric BWR/4 Plants. The changes reflected in Revision 1 resulted from the experience gained from license amendment applications to convert to these improved STS or to adopt partial improvements to existing technical specifications. This NUREG is the result of extensive public technical meetings and discussions between the Nuclear Regulatory Commission (NRC) staff and various nuclear power plant licensees, Nuclear Steam Supply System (NSSS) Owners Groups, NSSS vendors, and the Nuclear Energy Institute (NEI). The improved STS were developed based on the criteria in the Final Commission Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors, dated July 22, 1993. The improved STS will be used as the basis for individual nuclear power plant licensees to develop improved plant-specific technical specifications. This report contains three volumes. Volume 1 contains the Specifications for all chapters and sections of the improved STS. Volume 2 contains the Bases for Chapters 2.0 and 3.0, and Sections 3.1--3.3 of the improved STS. Volume 3 contains the Bases for Sections 3.4--3.10 of the improved STS

  15. Commonalty initiatives in US nuclear power plants to improve radiation protection culture and worker efficiency

    International Nuclear Information System (INIS)

    Wood, W.; Miller, D.

    2003-01-01

    Many US nuclear power plants have learned that common procedures, policies, instrumentation, tools and work practices achieve improvements to the radiation protection culture. Significant worker efficiency achievements are accomplished especially during refuelling outages. This paper discusses commonalty initiatives currently being implemented at many US Plants to address management challenges presented by deregulation of the US electric industry, reduction in the pool of outage contractors and aging of the experienced radiation worker population. The new INPO 2005 dose goals of 650 person-mSv/year for PWRs and 1200 person-mSv/yr for PWRs will require new approaches to radiation protection management to achieve these challenging goals by 2005. (authors)

  16. Industrial Fuel Gas Demonstration Plant Program. Conceptual design and evaluation of commercial plant. Volume III. Economic analyses (Deliverable Nos. 15 and 16)

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-01-01

    This report presents the results of Task I of Phase I in the form of a Conceptual Design and Evaluation of Commercial Plant report. The report is presented in four volumes as follows: I - Executive Summary, II - Commercial Plant Design, III - Economic Analyses, IV - Demonstration Plant Recommendations. Volume III presents the economic analyses for the commercial plant and the supporting data. General cost and financing factors used in the analyses are tabulated. Three financing modes are considered. The product gas cost calculation procedure is identified and appendices present computer inputs and sample computer outputs for the MLGW, Utility, and Industry Base Cases. The results of the base case cost analyses for plant fenceline gas costs are as follows: Municipal Utility, (e.g. MLGW), $3.76/MM Btu; Investor Owned Utility, (25% equity), $4.48/MM Btu; and Investor Case, (100% equity), $5.21/MM Btu. The results of 47 IFG product cost sensitivity cases involving a dozen sensitivity variables are presented. Plant half size, coal cost, plant investment, and return on equity (industrial) are the most important sensitivity variables. Volume III also presents a summary discussion of the socioeconomic impact of the plant and a discussion of possible commercial incentives for development of IFG plants.

  17. Survey of fish impingement at power plants in the United States. Volume I. The Great Lakes

    International Nuclear Information System (INIS)

    Sharma, R.K.; Freeman, R.F. III.

    1977-03-01

    Impingement of fish at cooling-water intakes of 20 power plants located on the Great Lakes has been surveyed and data are presented. Descriptions of site, plant, and intake design and operation are provided. Reports in this volume summarize impingement data for individual plants in tabular and histogram formats. Information was available from differing sources such as the utilities themselves, public documents, regulatory agencies, and others. Thus, the extent of detail in the reports varies greatly from plant to plant. Histogram preparation involved an extrapolation procedure that has inadequacies. The reader is cautioned in the use of information presented in this volume to determine intake-design acceptability or intensity of impacts on ecosystems. No conclusions are presented herein; data comparisons are made in Volume IV

  18. Economic and Environmental Impacts of the Columbia-Snake River Extended Lock Outage

    Science.gov (United States)

    2012-03-01

    This reports main objective is to analyze the change in rates and modal costs for shippers, commodity industries and ports prior to, during and after the fifteen week lock outage and to determine the impacts on the environment in the form of energ...

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

    KAUST Repository

    Khafagy, Mohammad Galal; Ismail, Amr; Alouini, Mohamed-Slim; Aissa, Sonia

    2013-01-01

    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.

  20. Outage Analysis of Mixed Underlay Cognitive RF MIMO and FSO Relaying with Interference Reduction

    KAUST Repository

    Al-Qahtani, Fawaz S.; El-Malek, Ahmed H. Abd; Ansari, Imran S.; Radaydeh, Redha Mahmoud Mesleh; Zummo, Salam A.

    2017-01-01

    In this paper, we study the outage performance of multiuser mixed underlay radio frequency (RF)/multidestinations free-space optical (FSO) links. For RF links, we consider a secondary network with multiple users that can communicate with multiple destinations through a relaying node. The relay is equipped with an antenna array at the RF side, and it uses the amplify-and-forward (AF) protocol. The primary users (PUs) are equipped with multiple antennas at transmit and receive nodes. The RF link is subjected to the aggregate PUs interference effect on the secondary network. To reduce the effect of PUs interference on secondary network at the relay node, two interference cancellation (IC) schemes are adopted, which vary in terms of complexity and achieved performance. On the other hand, the multidestination FSO links can be exploited to further enhance the quality of the second hop, and their associated channel models account for pointing errors, intensity modulation/direct detection, and heterodyne detection. For the aforementioned system model, we obtain exact and asymptotic closed-form expressions for the end-to-end outage probability. To further enhance system performance, optimal power allocation between the two hops is obtained based on the derived asymptotic outage probability expressions.

  1. 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.

  2. Outage Analysis of Mixed Underlay Cognitive RF MIMO and FSO Relaying with Interference Reduction

    KAUST Repository

    Al-Qahtani, Fawaz S.

    2017-03-22

    In this paper, we study the outage performance of multiuser mixed underlay radio frequency (RF)/multidestinations free-space optical (FSO) links. For RF links, we consider a secondary network with multiple users that can communicate with multiple destinations through a relaying node. The relay is equipped with an antenna array at the RF side, and it uses the amplify-and-forward (AF) protocol. The primary users (PUs) are equipped with multiple antennas at transmit and receive nodes. The RF link is subjected to the aggregate PUs interference effect on the secondary network. To reduce the effect of PUs interference on secondary network at the relay node, two interference cancellation (IC) schemes are adopted, which vary in terms of complexity and achieved performance. On the other hand, the multidestination FSO links can be exploited to further enhance the quality of the second hop, and their associated channel models account for pointing errors, intensity modulation/direct detection, and heterodyne detection. For the aforementioned system model, we obtain exact and asymptotic closed-form expressions for the end-to-end outage probability. To further enhance system performance, optimal power allocation between the two hops is obtained based on the derived asymptotic outage probability expressions.

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

    Science.gov (United States)

    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.

  4. Monitoring Disaster-Related Power Outages Using NASA Black Marble Nighttime Light Product

    Science.gov (United States)

    Wang, Z.; Román, M. O.; Sun, Q.; Molthan, A. L.; Schultz, L. A.; Kalb, V. L.

    2018-04-01

    Timely and accurate monitoring of disruptions to the electricity grid, including the magnitude, spatial extent, timing, and duration of net power losses, is needed to improve situational awareness of disaster response and long-term recovery efforts. Satellite-derived Nighttime Lights (NTL) provide an indication of human activity patterns and have been successfully used to monitor disaster-related power outages. The global 500 m spatial resolution National Aeronautics and Space Administration (NASA) Black Marble NTL daily standard product suite (VNP46) is generated from Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) onboard the NASA/National Oceanic and Atmospheric Administration (NOAA) Suomi National Polar-orbiting Partnership (Suomi- NPP) satellite, which began operations on 19 January 2012. With its improvements in product accuracy (including critical atmospheric and BRDF correction routines), the VIIRS daily Black Mable product enables systematic monitoring of outage conditions across all stages of the disaster management cycle.

  5. 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%.

  6. Operation of Finnish nuclear power plants

    International Nuclear Information System (INIS)

    Tossavainen, K.

    1991-02-01

    During the third quarter of 1990 the Finnish nuclear power plant units Loviisa 1 and 2 and TVO I and II were in commercial operation for most of the time. The annual maintenance outages of the Loviisa plant units were held during the report period. All events during this quarter are classified as Level hero (Below Scale) on the International Nuclear Event Scale. Occupational radiation doses and external releases of radioactivity were below authorised limits. Only small amounts of radioactive substances originating in nuclear power plants were detected in samples taken in the vicinity of nuclear power plants

  7. APPROACH TO ASSESSING THE PREPAREDNESS OF HOSPITALS TO POWER OUTAGES

    Directory of Open Access Journals (Sweden)

    Lenka BREHOVSKÁ

    2017-06-01

    Full Text Available Within the secondary impacts of electricity blackouts, it is necessary to pay attention to facilities providing medical care for the population, namely the hospitals. Hospitals represent a key position in the provision of health care also in times of crisis. These facilities must provide constant care; it is therefore essential that the preparedness of such facilities is kept at a high level. The basic aim of this article is to analyse the preparedness of hospitals to power outages (power failures, blackouts within a pilot study. On that basis, a SWOT analysis is used to determine strengths and weaknesses of the system of preparedness of hospitals to power outages and solutions for better security of hospitals are defined. The sample investigated consists of four hospitals founded by the Regional Authority (hospitals Nos. 1-4 and one hospital founded by the Ministry of Health of the Czech Republic (hospital No. 5. The results of the study shows that most weaknesses of the preparedness of hospitals are represented by inadequately addressed reserves of fuel for the main backup power supply, poor knowledge of employees who are insufficiently retrained, and old backup power supplies (even 35 years in some cases.

  8. Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 2. Appendices. [Appendices only

    Energy Technology Data Exchange (ETDEWEB)

    Liverman, James L.

    1977-09-01

    Volume 2 is comprised of appendices: Portsmouth Gaseous Diffusion Plant Existing Facilities; Ecology; Civic Involvement; Social Analysis; Population Projections; Toxicity of Air Pollutants to Biota at Portsmouth Gaseous Diffusion Plant; and Assessment of Noise Effects of an Add-On to the Portsmouth Gaseous Diffusion Plant. (LK)

  9. Configuration management of plant modifications for nuclear power plants

    International Nuclear Information System (INIS)

    Ritsch, W.J.

    1987-01-01

    Due to the increasing complexity of nuclear power plant operation, regulatory pressure, and the large numbers of people required to operate and support the stations, the control of plant modifications at these plants needs to be expanded and improved. The aerospace and defense industries, as well as the owners or operators of large energy projects have established configuration management programs (CMPs) to control plant design changes. These programs are composed of well-defined functions for identifying, evaluating, recording, tracking, issuing, and documenting the established baseline conditions, as well as required changes to these baseline conditions. The purpose of this paper is to describe a recommended CMP for plant modifications consisting of a computerized data base installed on the utility's computer to provide a central storage of plant design and operations data necessary to control the following activities as they are affected by plant design changes: training; record management; operations; maintenance; health physics; planning/scheduling; procurement/inventory control; outage management (including modifications); and emergency response

  10. 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.

  11. Nuclear power plant operating experience. Annual report, 1978

    International Nuclear Information System (INIS)

    Beebe, M.R.

    1979-12-01

    This report is the fifth in a series of reports issued annually that summarizes the operating experience of US nuclear power plants in commercial operation. Power generation statistics, plant outages, reportable occurrences, fuel element performance, occupational radiation exposure for each plant are presented. Summary highlights of these areas are discussed. The report includes 1978 data from 65 plants - 25 boiling water reactor plants and 40 pressurized water reactor plants. Discussion of radioactive effluents which has been a part of this report in previous years, has not been included in this issue because of late acquisition of data

  12. Failed fuel rod detection system and computerized manipulator during outages

    International Nuclear Information System (INIS)

    Boehm, H.H.; Foerch, H.

    1984-01-01

    During regular outages spent fuel assemblies need to be replaced and relocated within the core. Defective fuel rods in particular fuel assemblies have to be removed from further service and before delivery of such faulty fuel assemblies to a reprocessing plant. The system which Brown Boveri Reaktor GmbH and Krautkraemer have developed in the Federal Republic of Germany is capable of directly locating the defective rods in a proper fuel assembly. Inspection times are comparable to those of standard sipping methods, with the advantages of immediately available results and direct identification of the defective fuel rods. During the repair of fuel assemblies this system allows withdrawal of individual defective rods. With the sipping method all the fuel rods of a defective fuel assembly need to be removed and inspected by eddy current testing. During steam generator inspection and repair personnel are exposed to ample radiation. A remotely controlled, computerized manipulator was used to significantly reduce the radiation dose by automating steps in the procedures; at the same time inspection and repair times were reduced. The main features of the manipulator are a rigid component construction of the leg and two arms, and a resolver control for horizontal and vertical motion that enables rapid and accurate access to a desired tube (author)

  13. Development of the Bayesian method for unavailability inference. The new inferential theory and the examples of inference using BWR outage data in Japan

    International Nuclear Information System (INIS)

    Nakamura, Makoto

    2009-01-01

    It is important for Level 1 PSA to quantify input reliability parameters and their uncertainty. Bayesian methods for inference of system/component unavailability, however, are not well studied. At present practitioners allocate the uncertainty (i.e. error factor) of the unavailability based on engineering judgment. Systematic methods based on Bayesian statistics are needed for quantification of such uncertainty. In this study we have developed a new method for Bayesian inference of unavailability, where the posterior of system/component unavailability is described by the inverted gamma distribution. We show that the average of the posterior comes close to the point estimate of the unavailability as the number of outages goes to infinity. That indicates validity of the new method. Using plant data recorded in NUCIA, we have applied the new method to inference of system unavailability under unplanned outages due to violations of LCO at BWRs in Japan. According to the inference results, the unavailability is populated in the order of 10 -5 -10 -4 and the error factor is within 1-2. Thus, the new Bayesian method allows one to quantify magnitudes and widths (i.e. error factor) of uncertainty distributions of unavailability. (author)

  14. The System 80+ Standard Plant design control document. Volume 2

    International Nuclear Information System (INIS)

    1997-01-01

    This Design Control Document (DCD) is a repository of information comprising the System 80+trademark Standard Plant Design. The DCD also provides that design-related information to be incorporated by reference in the design certification rule for the System 80+ Standard Plant Design. Applicants for a combined license pursuant to 10 CFR 52 must ensure that the final Design Certification Rule and the associated Statements of Consideration are used when making all licensing decisions relevant to the System 80+ Standard Plant Design. The Design Control Document contains the DCD introduction, The Certified Design Material (CDM) [i.e., ''Tier 1''] and the Approved Design Material (ADM) [i.e., ''Tier 2''] for the System 80+ Standard Plant Design. The CDM includes the following sections: (1) Introductory material; (2) Certified Design Material for System 80+ systems and structures; (3) Certified Design Material for non-system-based aspects of the System 80+ Certified design; (4) Interface requirements; and (5) Site parameters. The ADM, to the extent applicable for the System 80+ Standard Plant Design, includes: (1) the information required for the final safety analysis report under 20 CFR 50.34; (2) other relevant information required by 10 CFR 52.47; and (3) emergency operations guidelines. This volume covers the following information of the CDM: (2.8) Steam and power conversion; (2.9) Radioactive waste management; (2.10) Tech Support Center; (2.11) Initial test program; (2.12) Human factors; and sections 3, 4, and 5. Also covered in this volume are parts 1--6 of section 1 (General Plant Description) of the ADM Design and Analysis

  15. Manufacture of sockets of volume compensators in nuclear power plants

    International Nuclear Information System (INIS)

    Andreev, V.P.; Tshekotilo, L.V.; Shevtshenko, N.T.; Sevruk, A.N.; Wolacek, W.J.; Irsicek, L.; Vrbensky, J.

    1982-01-01

    Experience is reported with regard to electroslag casting of sockets of volume compensators or steam separators used in nuclear power plants. According to the method the raw pieces are casted directly at the surface of the enclosures

  16. Human errors and work performance in a nuclear power plant control room: associations with work-related factors and behavioral coping

    International Nuclear Information System (INIS)

    Kecklund, Lena Jacobsson; Svenson, Ola

    1997-01-01

    The present study investigated the relationships between the operator's appraisal of his own work situation and the quality of his own work performance as well as self-reported errors in a nuclear power plant control room. In all, 98 control room operators from two nuclear power units filled out a questionnaire and several diaries during two operational conditions, annual outage and normal operation. As expected, the operators reported higher work demands in annual outage as compared to normal operation. In response to the increased demands, the operators reported that they used coping strategies such as increased effort, decreased aspiration level for work performance quality and increased use of delegation of tasks to others. This way of coping does not reflect less positive motivation for the work during the outage period. Instead, the operators maintain the same positive motivation for their work, and succeed in being more alert during morning and night shifts. However, the operators feel less satisfied with their work result. The operators also perceive the risk of making minor errors as increasing during outage. The decreased level of satisfaction with work result during outage is a fact despite the lowering of aspiration level for work performance quality during outage. In order to decrease relative frequencies for minor errors, special attention should be given to reduce work demands, such as time pressure and memory demands. In order to decrease misinterpretation errors special attention should be given to organizational factors such as planning and shift turnovers in addition to training. In summary, the outage period seems to be a significantly more vulnerable window in the management of a nuclear power plant than the normal power production state. Thus, an increased focus on the outage period and human factors issues, addressing the synergetic effects or work demands, organizational factors and coping resources is an important area for improvement of

  17. MONITORING DISASTER-RELATED POWER OUTAGES USING NASA BLACK MARBLE NIGHTTIME LIGHT PRODUCT

    Directory of Open Access Journals (Sweden)

    Z. Wang

    2018-04-01

    Full Text Available Timely and accurate monitoring of disruptions to the electricity grid, including the magnitude, spatial extent, timing, and duration of net power losses, is needed to improve situational awareness of disaster response and long-term recovery efforts. Satellite-derived Nighttime Lights (NTL provide an indication of human activity patterns and have been successfully used to monitor disaster-related power outages. The global 500 m spatial resolution National Aeronautics and Space Administration (NASA Black Marble NTL daily standard product suite (VNP46 is generated from Visible Infrared Imaging Radiometer Suite (VIIRS Day/Night Band (DNB onboard the NASA/National Oceanic and Atmospheric Administration (NOAA Suomi National Polar-orbiting Partnership (Suomi- NPP satellite, which began operations on 19 January 2012. With its improvements in product accuracy (including critical atmospheric and BRDF correction routines, the VIIRS daily Black Mable product enables systematic monitoring of outage conditions across all stages of the disaster management cycle.

  18. Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Analysis of core damage frequency from internal fire events for Plant Operational State 5 during a refueling outage. Volume 3

    International Nuclear Information System (INIS)

    Lambright, J.; Yakle, J.

    1994-07-01

    This report, Volume 3, presents the details of the analysis of core damage frequency due to fire during shutdown Plant Operational State 5 at the Grand Gulf Nuclear Station. Insights from previous fire analyses (Peach Bottom, Surry, LaSalle) were used to the greatest extent possible in this analysis. The fire analysis was fully integrated utilizing the same event trees and fault trees that were used in the internal events analysis. In assessing shutdown risk due to fire at Grand Gulf, a detailed screening was performed which included the following elements: (a) Computer-aided vital area analysis; (b) Plant inspections; (c) Credit for automatic fire protection systems; (d) Recovery of random failures; (e) Detailed fire propagation modeling. This screening process revealed that all plant areas had a negligible (<1.0E-8 per year) contribution to fire-induced core damage frequency

  19. Evaluation of mean time between forced outage for reactor protection system using RBD and failure rate

    International Nuclear Information System (INIS)

    Lee, D. Y.; Park, J. H.; Hwang, I. K.; Cha, K. H.; Choi, J. K.; Lee, K. Y.; Park, J. K.

    2001-01-01

    The design life of nuclear power plants (NPPs) under recent construction is about fifty to sixty years. However, the duration that equipments of control systems operate without failures is at most five to ten years. Design for diversity and adequate maintenance strategy are required for NPP protection system in order to use the control equipment which has shorter life time than the design life of NPP. Fault Tree Analysis (FTA) technique, which has been applied to Probabilistics Safety Analysis (PSA), has been introduced to quantitatively evaluate the reliability of NPP I and C systems. The FTA, however, cannot properly consider the effect of maintenance. In this work, we have reviewed quantitative reliability evaluation techniques using the reliability block diagram and failure rates and applied it to the evaluation of mean time between forced outage for reactor protection system

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

    KAUST Repository

    Mehbodniya, Abolfazl; Aissa, Sonia

    2011-01-01

    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

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

    KAUST Repository

    Rezki, Zouheir; Alouini, Mohamed-Slim

    2014-01-01

    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

  2. Survey of fish impingement at power plants in the United States. Volume III. Estuaries and coastal waters

    International Nuclear Information System (INIS)

    Stupka, R.C.; Sharma, R.K.

    1977-03-01

    Impingement of fish at cooling-water intakes of 32 power plants, located on estuaries and coastal waters has been surveyed and data are presented. Descriptions of site, plant, and intake design and operation are provided. Reports in this volume summarize impingement data for individual plants in tabular and histogram formats. Information was available from differing sources such as the utilities themselves, public documents, regulatory agencies, and others. Thus, the extent of detail in the reports varies greatly from plant to plant. Histogram preparation involved an extrapolation procedure that has inadequacies. The reader is cautioned in the use of information presented in this volume to determine intake-design acceptability or intensity of impacts on ecosystems. No conclusions are presented herein; data comparisons are made in Volume IV

  3. Survey of fish impingement at power plants in the United States. Volume III. Estuaries and coastal waters

    Energy Technology Data Exchange (ETDEWEB)

    Stupka, Richard C.; Sharma, Rajendra K.

    1977-03-01

    Impingement of fish at cooling-water intakes of 32 power plants, located on estuaries and coastal waters has been surveyed and data are presented. Descriptions of site, plant, and intake design and operation are provided. Reports in this volume summarize impingement data for individual plants in tabular and histogram formats. Information was available from differing sources such as the utilities themselves, public documents, regulatory agencies, and others. Thus, the extent of detail in the reports varies greatly from plant to plant. Histogram preparation involved an extrapolation procedure that has inadequacies. The reader is cautioned in the use of information presented in this volume to determine intake-design acceptability or intensity of impacts on ecosystems. No conclusions are presented herein; data comparisons are made in Volume IV.

  4. 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.

  5. Power plant cycle chemistry - a currently neglected power plant chemistry discipline

    International Nuclear Information System (INIS)

    Bursik, A.

    2005-01-01

    Power plant cycle chemistry seems to be a stepchild at both utilities and universities and research organizations. It is felt that other power plant chemistry disciplines are more important. The last International Power Cycle Chemistry Conference in Prague may be cited as an example. A critical review of the papers presented at this conference seems to confirm the above-mentioned statements. This situation is very unsatisfactory and has led to an increasing number of component failures and instances of damage to major cycle components. Optimization of cycle chemistry in fossil power plants undoubtedly results in clear benefits and savings with respect to operating costs. It should be kept in mind that many seemingly important chemistry-related issues lose their importance during forced outages of units practicing faulty plant cycle chemistry. (orig.)

  6. Organizational analysis and safety for utilities with nuclear power plants: an organizational overview. Volume 1

    International Nuclear Information System (INIS)

    Osborn, R.N.; Olson, J.; Sommers, P.E.; McLaughlin, S.D.; Jackson, M.S.; Scott, W.G.; Connor, P.E.

    1983-08-01

    This two-volume report presents the results of initial research on the feasibility of applying organizational factors in nuclear power plant (NPP) safety assessment. A model is introduced for the purposes of organizing the literature review and showing key relationships among identified organizational factors and nuclear power plant safety. Volume I of this report contains an overview of the literature, a discussion of available safety indicators, and a series of recommendations for more systematically incorporating organizational analysis into investigations of nuclear power plant safety

  7. Insights from the analyses of risk-informed extension of diesel generator allowed outage time

    International Nuclear Information System (INIS)

    Lin, J.C.; He Wei

    2005-01-01

    In recent years, many U.S. nuclear plants have applied and received approval for the risk-informed extension of the Allowed Outage Time (AOT) for Emergency Diesel Generators (EDGs). These risk-informed applications need to meet the regulatory guidance on the risk criteria. This paper discusses in detail insights derived from the risk-informed analyses performed to support these applications. The risk criteria on ΔCDF/ΔLERF evaluate the increase in average risk by extending the AOT for EDGs, induced primarily by an increase in EDG maintenance unavailability due to the introduction of additional EDG preventive maintenance. By performing this preventive maintenance work on-line, the outage duration can be shortened. With proper refinement of the risk model, most plants can meet the ΔCDF/ΔLERF criteria for extending the EDGAOT from, for example, 3 days to 14 days. The key areas for model enhancements to meet these criteria include offsite/onsite power recovery, LERF modeling, etc. The most important LERF model enhancements consist of refinement of the penetrations included in the containment isolation model for the consideration of a large release, and taking credit for operator vessel depressurization during the time period between core damage and vessel failure. A recent study showed that although the frequency of loss of offsite power (LOSP) has decreased, the duration of offsite power recovery has actually increased. However, many of the events used to derive this conclusion may not be applicable to PRAs. One approach develops the offsite power non-recovery factor by first screening the LOSP events for applicability to the plant being analyzed, power operation, and LOSP initiating event, then using the remaining events data for the derivation based on the fraction of events with recovery duration longer than the time window allowed. The risk criteria on ICCDP/ICLERP examine the increase in risk from the average CDF/LERF, based on the increased maintenance

  8. U.S. Nuclear Power Plant Operating Cost and Experience Summaries

    International Nuclear Information System (INIS)

    Reid, RL

    2003-01-01

    The ''U.S. Nuclear Power Plant Operating Cost and Experience Summaries'' (NUREG/CR-6577, Supp. 2) report has been prepared to provide historical operating cost and experience information on U.S. commercial nuclear power plants during 2000-2001. Costs incurred after initial construction are characterized as annual production costs, which represent fuel and plant operating and maintenance expenses, and capital expenditures related to facility additions/modifications, which are included in the plant capital asset base. As discussed in the report, annual data for these two cost categories were obtained from publicly available reports and must be accepted as having different degrees of accuracy and completeness. Treatment of inconclusive and incomplete data is discussed. As an aid to understanding the fluctuations in the cost histories, operations summaries for each nuclear unit are provided. The intent of these summaries is to identify important operating events; refueling, major maintenance, and other significant outages; operating milestones; and significant licensing or enforcement actions. Information used in the summaries is condensed from operating reports submitted by the licensees, the Nuclear Regulatory Commission (NRC) database for enforcement actions, and outage reports

  9. On Secrecy Outage of Relay Selection in Underlay Cognitive Radio Networks over Nakagami-m Fading Channels

    KAUST Repository

    Lei, Hongjiang; Zhang, Huan; Ansari, Imran Shafique; Ren, Zhi; Pan, Gaofeng; Qaraqe, Khalid A.; Alouini, Mohamed-Slim

    2017-01-01

    In this paper, the secrecy outage performance of an underlay cognitive decode-and-forward relay network over independent but not necessarily identical distributed (i.n.i.d) Nakagami-m fading channels is investigated, in which the secondary user transmitter communicates with the secondary destination via relays, and an eavesdropper attempts to overhear the information. Based on whether the channel state information (CSI) of the wiretap links is available or not, we analyze the secrecy outage performance with optimal relay selection (ORS) and suboptimal relay selection (SRS) schemes, and multiple relays combining scheme (MRC) scheme is considered for comparison purpose. The exact and asymptotic closed-form expressions for the secrecy outage probability with three different relay selection schemes are derived and verified by Monte-Carlo simulations. The numerical results illustrate that ORS scheme always outperforms SRS and MRC schemes, and SRS scheme is better than MRC scheme in the lower fading parameters scenario. Furthermore, through asymptotic analysis, we find that these three different schemes achieve the same secrecy diversity order, which is determined by the number of the relays, and the fading parameters of the links among the relays and the destination.

  10. On Secrecy Outage of Relay Selection in Underlay Cognitive Radio Networks over Nakagami-m Fading Channels

    KAUST Repository

    Lei, Hongjiang

    2017-10-02

    In this paper, the secrecy outage performance of an underlay cognitive decode-and-forward relay network over independent but not necessarily identical distributed (i.n.i.d) Nakagami-m fading channels is investigated, in which the secondary user transmitter communicates with the secondary destination via relays, and an eavesdropper attempts to overhear the information. Based on whether the channel state information (CSI) of the wiretap links is available or not, we analyze the secrecy outage performance with optimal relay selection (ORS) and suboptimal relay selection (SRS) schemes, and multiple relays combining scheme (MRC) scheme is considered for comparison purpose. The exact and asymptotic closed-form expressions for the secrecy outage probability with three different relay selection schemes are derived and verified by Monte-Carlo simulations. The numerical results illustrate that ORS scheme always outperforms SRS and MRC schemes, and SRS scheme is better than MRC scheme in the lower fading parameters scenario. Furthermore, through asymptotic analysis, we find that these three different schemes achieve the same secrecy diversity order, which is determined by the number of the relays, and the fading parameters of the links among the relays and the destination.

  11. Outage Probability versus Fairness Trade-off in Opportunistic Relay Selection with Outdated CSI

    Directory of Open Access Journals (Sweden)

    Vicario JoseLopez

    2009-01-01

    Full Text Available We analyze the existing trade-offs in terms of system performance versus fairness of a cooperative system based on opportunistic relay selection (ORS and with outdated channel state information (CSI. In particular, system performance is analytically evaluated in terms of outage probability, and the fairness behavior is assessed based on the power consumption at the different relays. In order to improve the fairness behavior of ORS while keeping the selection diversity gain, we propose a relay selection mechanism where the relay with the highest normalized signal-to-noise ratio (SNR is selected for relaying the source's information. The proposed strategy is compared with existing relay selection strategies by adopting a novel graphical representation inspired by expected profit versus risk plots used in modern portfolio theory. As shown in the paper, this strategy allows operating the system in more favorable points of the outage versus fairness region.

  12. Use of expert systems in nuclear power plants

    International Nuclear Information System (INIS)

    Uhrig, R.E.

    1989-01-01

    The application of technologies, particularly expert systems, to the control room activities in a nuclear power plant has the potential to reduce operator error and increase plant safety, reliability, and efficiency. Furthermore, there are a large number of nonoperating activities (testing, routine maintenance, outage planning, equipment diagnostics, and fuel management) in which expert systems can increase the efficiency and effectiveness of overall plant and corporate operations. This document presents a number of potential applications of expert systems in the nuclear power field. 36 refs., 2 tabs

  13. Operation of Finnish nuclear power plants. Quarterly report, 2nd quarter 1997

    International Nuclear Information System (INIS)

    Tossavainen, K.

    1997-12-01

    Quarterly Reports on the operation of Finnish nuclear power plants describe events and observations relating to nuclear and radiation safety which STUK - Radiation and Nuclear Safety Authority considers safety significant. Safety improvements at the plants are also described. The Report also includes a summary of the radiation safety of plant personnel and of the environment and tabulated data on the plants' production and load factors. The Finnish nuclear power plant units were in power operation in the second quarter of 1997, except for the annual maintenance outages of Olkiluoto plant units and the Midsummer outage at Olkiluoto 2 due to reduced demand for electricity. There were also brief interruptions in power operation at the Olkiluoto plant units due to three reactor scrams. All plant units are undergoing long-term test operation at upgraded reactor power level which has been approved by STUK The load factor average of all plant units was 88.7 %. One event in the second quarter of 1997 was classified level 1 on the INES. The event in question was a scram at Olkiluoto 1 which was caused by erroneous opening of switches. Other events in this quarter were level 0. Occupational doses and radioactive releases off-site were below authorized limits. Radioactive substances were measurable in samples collected around the plants in such quantities only as have no bearing on the radiation exposure of the population. (orig.)

  14. State of the art review of radioactive waste volume reduction techniques for commercial nuclear power plants

    International Nuclear Information System (INIS)

    1980-04-01

    A review is made of the state of the art of volume reduction techniques for low level liquid and solid radioactive wastes produced as a result of: (1) operation of commercial nuclear power plants, (2) storage of spent fuel in away-from-reactor facilities, and (3) decontamination/decommissioning of commercial nuclear power plants. The types of wastes and their chemical, physical, and radiological characteristics are identified. Methods used by industry for processing radioactive wastes are reviewed and compared to the new techniques for processing and reducing the volume of radioactive wastes. A detailed system description and report on operating experiences follow for each of the new volume reduction techniques. In addition, descriptions of volume reduction methods presently under development are provided. The Appendix records data collected during site surveys of vendor facilities and operating power plants. A Bibliography is provided for each of the various volume reduction techniques discussed in the report

  15. A Unified Simulation Approach for the Fast Outage Capacity Evaluation over Generalized Fading Channels

    KAUST Repository

    Rached, Nadhir B.; Kammoun, Abla; Alouini, Mohamed-Slim; Tempone, Raul

    2016-01-01

    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

  16. Impact of power plant reliability on the choice of operating parameter values

    International Nuclear Information System (INIS)

    Kramer, R.A.

    1985-01-01

    In this thesis, the basic structure for the development of a methodology to evaluate the effect of operating parameters on plant availability and generating system economic dispatch optimization is described. Plant availability is determined by a fault free model. In this model historic, time dependent, component induced forced outage data is utilized as the basis for the calculation of projected plant forced outage rates. The influence of a particular fuel-cycle length at a specific generating station on the operational planning of a multi unit generating system is considered. The basis of the dispatch of units in this analysis is optimal economic operation, i.e., the minimization of the cost of reliability supplying electricity to the system's customers. As a result of the utilization of this technique, a simplified example that considers the choice between a 12- and 18-month fuel cycle length is evaluated in terms of its impact on plant availability, fuel cycle economics and overall optimal generating system economic dispatch. The reliability portion of this methodology is applied to a simplified representation of the recirculation system of a pressurized water reactor nuclear power plant to illustrate the analytic techniques

  17. 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)

  18. Intermediate report of MoReMo. Modelling resilience for maintenance and outage

    International Nuclear Information System (INIS)

    Oedewald, P.; Macchi, L.; Axelsson, C.; Eitrheim, M.H.R.

    2012-02-01

    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)

  19. Mirror Advanced Reactor Study (MARS). Final report. Volume 1-B. Commercial fusion electric plant

    International Nuclear Information System (INIS)

    Donohue, M.L.; Price, M.E.

    1984-07-01

    Volume 1-B contains the following chapters: (1) blanket and reflector; (2) central cell shield; (3) central cell structure; (4) heat transport and energy conversion; (5) tritium systems; (6) cryogenics; (7) maintenance; (8) safety; (9) radioactivity, activation, and waste disposal; (10) instrumentation and control; (11) balance of plant; (12) plant startup and operation; (13) plant availability; (14) plant construction; and (15) economic analysis

  20. Mirror Advanced Reactor Study (MARS). Final report. Volume 1-B. Commercial fusion electric plant

    Energy Technology Data Exchange (ETDEWEB)

    Donohue, M.L.; Price, M.E. (eds.)

    1984-07-01

    Volume 1-B contains the following chapters: (1) blanket and reflector; (2) central cell shield; (3) central cell structure; (4) heat transport and energy conversion; (5) tritium systems; (6) cryogenics; (7) maintenance; (8) safety; (9) radioactivity, activation, and waste disposal; (10) instrumentation and control; (11) balance of plant; (12) plant startup and operation; (13) plant availability; (14) plant construction; and (15) economic analysis.

  1. Feasibility study for a 10-MM-GPY fuel ethanol plant, Brady Hot Springs, Nevada. Volume 1. Process and plant design

    Energy Technology Data Exchange (ETDEWEB)

    1980-09-01

    An investigation was performed to determine the technical and economic viability of constructing and operating a geothermally heated, biomass, motor fuel alcohol plant at Brady's Hot Springs. The results of the study are positive, showing that a plant of innovative, yet proven design can be built to adapt current commerical fermentation-distillation technology to the application of geothermal heat energy. The specific method of heat production from the Brady's Hot Spring wells has been successful for some time at an onion drying plant. Further development of the geothermal resource to add the capacity needed for an ethanol plant is found to be feasible for a plant sized to produce 10 million gallons of motor fuel grade ethanol per year. A very adequate supply of feedgrains is found to be available for use in the plant without impact on the local or regional feedgrain market. The effect of diverting supplies from the animal feedlots in Northern Nevada and California will be mitigated by the by-product output of high-protein feed supplements that the plant will produce. The plant will have a favorable impact on the local farming economies of Fallon, Lovelock, Winnemucca and Elko, Nevada. It will make a positive and significant socioeconomic contribution to Churchill County, providing direct employment for an additional 61 persons. Environmental impact will be negligible, involving mostly a moderate increase in local truck traffic and railroad siding activity. The report is presented in two volumes. Volume 1 deals with the technical design aspects of the plant. The second volume addresses the issue of expanded geothermal heat production at Brady's Hot Springs, goes into the details of feedstock supply economics, and looks at the markets for the plant's primary ethanol product, and the markets for its feed supplement by-products. The report concludes with an analysis of the economic viability of the proposed project.

  2. The power outage of November 4, 2006: a plea for a genuine European energy policy

    International Nuclear Information System (INIS)

    Merlin, Andre

    2006-01-01

    As a power outage affected several millions European people in November 2006, this article identifies and discusses actions to be implemented at the European level to avoid such a situation and thus strengthen energy security for all European citizen. It proposes a detailed analysis of the situation of electricity transport grids before the incident, of what happened in terms of overloads for some very high voltage lines: the de-energizing of a line over the Ems River resulted in a domino triggering off of very high voltage lines connected to different areas of Europe; a decrease of current frequency resulted in the disconnection of power plants and grid managers had to reduce consumption in emergency. The article draws some early lessons of the incident before the UCTE (Power Transport Coordination Union) inquiry, and recommends some actions regarding grid coordination, harmonisation of abilities and decisions, and performance of provisional assessments of the electricity supply/demand balance

  3. The System 80+ Standard Plant design control document. Volume 15

    International Nuclear Information System (INIS)

    1997-01-01

    This Design Control Document (DCD) is a repository of information comprising the System 80+trademark Standard Plant Design. The DCD also provides that design-related information to be incorporated by reference in the design certification rule for the System 80+ Standard Plant Design. Applicants for a combined license pursuant to 10 CFR 52 must ensure that the final Design Certification Rule and the associated Statements of Consideration are used when making all licensing decisions relevant to the System 80+ Standard Plant Design. The Design Control Document contains the DCD introduction, The Certified Design Material (CDM) [i.e., ''Tier 1''] and the Approved Design Material (ADM) [i.e., ''Tier 2''] for the System 80+ Standard Plant Design. The CDM includes the following sections: (1) Introductory material; (2) Certified Design Material for System 80+ systems and structures; (3) Certified Design Material for non-system-based aspects of the System 80+ Certified design; (4) Interface requirements; and (5) Site parameters. The ADM, to the extent applicable for the System 80+ Standard Plant Design, includes: (1) the information required for the final safety analysis report under 20 CFR 50.34; (2) other relevant information required by 10 CFR 52.47; and (3) emergency operations guidelines. This volume contains all five parts of section 12 (Radiation Protection) of the ADM Design and Analysis. Topics covered are: ALARA exposures; radiation sources; radiation protection; dose assessment; and health physics program. All six parts and appendices A and B for section 13 (Conduct of Operations) of the ADM Design and Analysis are also contained in this volume. Topics covered are: organizational structure; training program; emergency planning; review and audit; plant procedures; industrial security; sabotage protection (App 13A); and vital equipment list (App 13B)

  4. 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.

  5. Gas Reactor International Cooperative program. Pebble bed reactor plant: screening evaluation. Volume 3. Appendix A. Equipment list

    International Nuclear Information System (INIS)

    1979-11-01

    This report consists of three volumes which describe the design concepts and screening evaluation for a 3000 MW(t) Pebble Bed Reactor Multiplex Plant (PBR-MX). The Multiplex plant produces both electricity and transportable chemical energy via the thermochemical pipeline (TCP). The evaluation was limited to a direct cycle plant which has the steam generators and steam reformers in the primary circuit. Volume 1 reports the overall plant and reactor system and was prepared by the General Electric Company. Core scoping studies were performed which evaluated the effects of annular and cylindrical core configurations, radial blanket zones, burnup, and ball heavy metal loadings. The reactor system, including the PCRV, was investigated for both the annular and cylindrical core configurations. Volume 3 is an Appendix containing the equipment list for the plant and was also prepared by United Engineers and Constructors, Inc. It tabulates the major components of the plant and describes each in terms of quantity, type, orientation, etc., to provide a basis for cost estimation

  6. I and C upgrading at nuclear power plants

    International Nuclear Information System (INIS)

    Tamiri, A.

    2003-01-01

    Continuing the operation of existing nuclear power plants will help reduce the number of new base-load nuclear and fossil power plants that need to be built. Old nuclear power plants in Canada are operating with analog instrumentation and control systems. For a number of reasons, such as changes and improvements in the applicable standards and design, maintenance problems due to the lack of spares, technical obsolescence, the need to increase power production, availability, reliability and safety, and in order to reduce operation and maintenance costs, instrumentation and control upgrading at nuclear power plants in a cost effective manner should be considered the greatest priority. Failures of instrumentation and control (I and C) due to aging and obsolescence issues may have an immediate negative impact on plant reliability and availability and also affect long-term plant performance and safety. In today's competitive marketplace, power plants are under pressure to cut spending on maintenance while reducing the risk of equipment failure that could cause unplanned outage. To improve plant safety and availability, old nuclear power plants will require investment in new technologies that can improve the performance and reduce the costs of generation by addressing the long term reliability of systems by up-grading to modem digital instrumentation and control and optimization opportunities. Boiler drum level control at nuclear power plants is critical for both plant protection and equipment safety and applies equality to high and low levels of water within the boiler drum. Plant outage studies at Pickering Nuclear have identified boiler drum level control and feed water control systems as major contributors to plant unavailability. Ways to improve transient and steady state response, upgrading existing poor analog control systems for boiler level and feed-water control systems at Pickering Nuclear, with enhanced and robust controller will be discussed in this paper

  7. Modernization of electric power systems of the Laguna Verde Nuclear Power Plant; Modernizacion de los sistemas electricos de potencia de la Central Nuclear de Laguna Verde

    Energy Technology Data Exchange (ETDEWEB)

    Gabaldon, M. A.; Gonzalez, J. J.; Prieto, I.

    2011-07-01

    The Power Increase Project of Laguna Verde Nuclear Plant has entailed the replacement, in one unique outage, of the main power electrical systems of the Plant (Isolated Phase Bars, Generator Circuit Breaker and Main Transformer) as well as the replacement of the Turbo-group. The simultaneous substitution of these entire system has never been done by any other Plant in the world, representing an engineering challenge that embraced the design of the new equipment up to the planning, coordination and management of the construction and commissioning works, which were successfully carried out by Iberdrola within the established outage period /47 days) for both units. (Author)

  8. The System 80+ Standard Plant design control document. Volume 11

    International Nuclear Information System (INIS)

    1997-01-01

    This Design Control Document (DCD) is a repository of information comprising the System 80+trademark Standard Plant Design. The DCD also provides that design-related information to be incorporated by reference in the design certification rule for the System 80+ Standard Plant Design. Applicants for a combined license pursuant to 10 CFR 52 must ensure that the final Design Certification Rule and the associated Statements of Consideration are used when making all licensing decisions relevant to the System 80+ Standard Plant Design. The Design Control Document contains the DCD introduction, The Certified Design Material (CDM) [i.e., ''Tier 1''] and the Approved Design Material (ADM) [i.e., ''Tier 2''] for the System 80+ Standard Plant Design. The CDM includes the following sections: (1) Introductory material; (2) Certified Design Material for System 80+ systems and structures; (3) Certified Design Material for non-system-based aspects of the System 80+ Certified design; (4) Interface requirements; and (5) Site parameters. The ADM, to the extent applicable for the System 80+ Standard Plant Design, includes: (1) the information required for the final safety analysis report under 20 CFR 50.34; (2) other relevant information required by 10 CFR 52.47; and (3) emergency operations guidelines. This volume covers parts 6 and 7 and appendix 7A for section 7 (Instrumentation and Control) of the ADM Design and Analysis. The topics covered by these are: other systems required for safety; control systems not required by safety; and CMF evaluation of limiting faults. Parts 1--3 of section 8 (Electric Power) of the ADM are also included in this volume. Topics covered by these parts are: introduction; offsite power system; and onsite power system

  9. The System 80+ Standard Plant design control document. Volume 23

    International Nuclear Information System (INIS)

    1997-01-01

    This Design Control Document (DCD) is a repository of information comprising the System 80+trademark Standard Plant Design. The DCD also provides that design-related information to be incorporated by reference in the design certification rule for the System 80+ Standard Plant Design. Applicants for a combined license pursuant to 10 CFR 52 must ensure that the final Design Certification Rule and the associated Statements of Consideration are used when making all licensing decisions relevant to the System 80+ Standard Plant Design. The Design Control Document contains the DCD introduction, The Certified Design Material (CDM) [i.e., ''Tier 1''] and the Approved Design Material (ADM) [i.e., ''Tier 2''] for the System 80+ Standard Plant Design. The CDM includes the following sections: (1) Introductory material; (2) Certified Design Material for System 80+ systems and structures; (3) Certified Design Material for non-system-based aspects of the System 80+ Certified design; (4) Interface requirements; and (5) Site parameters. The ADM, to the extent applicable for the System 80+ Standard Plant Design, includes: (1) the information required for the final safety analysis report under 20 CFR 50.34; (2) other relevant information required by 10 CFR 52.47; and (3) emergency operations guidelines. This volume contains part 16 References and Appendix 19 A Design Alternatives for section 19 (Probabilistic Risk Assessment) of the ADM Design and Analysis. Also covered is section 20 Unresolved Safety Issues of the ADM Design and Analysis. Finally sections 1--6 of the ADM Emergency Operations Guidelines are contained in this volume. Information covered in these sections include: standard post-trip actions; diagnostic actions; reactor trip recovery guideline; LOCA recovery; SG tube rupture recovery

  10. The System 80+ Standard Plant design control document. Volume 21

    International Nuclear Information System (INIS)

    1997-01-01

    This Design Control Document (DCD) is a repository of information comprising the System 80+trademark Standard Plant Design. The DCD also provides that design-related information to be incorporated by reference in the design certification rule for the System 80+ Standard Plant Design. Applicants for a combined license pursuant to 10 CFR 52 must ensure that the final Design Certification Rule and the associated Statements of Consideration are used when making all licensing decisions relevant to the System 80+ Standard Plant Design. The Design Control Document contains the DCD introduction, The Certified Design Material (CDM) [i.e., ''Tier 1''] and the Approved Design Material (ADM) [i.e., ''Tier 2''] for the System 80+ Standard Plant Design. The CDM includes the following sections: (1) Introductory material; (2) Certified Design Material for System 80+ systems and structures; (3) Certified Design Material for non-system-based aspects of the System 80+ Certified design; (4) Interface requirements; and (5) Site parameters. The ADM, to the extent applicable for the System 80+ Standard Plant Design, includes: (1) the information required for the final safety analysis report under 20 CFR 50.34; (2) other relevant information required by 10 CFR 52.47; and (3) emergency operations guidelines. This volume contains parts 1--10 of section 19 (Probabilistic Risk Assessment) of the ADM Design and Analysis. Topics covered are: methodology; initiating event evaluation; accident sequence determination; data analysis; systems analysis; external events analysis; shutdown risk assessment; accident sequence quantification; and sensitivity analysis. Also included in this volume are Appendix 19.8A Shutdown Risk Assessment and Appendix A to Appendix 19.8A Request for Information

  11. Sampled-data-based vibration control for structural systems with finite-time state constraint and sensor outage.

    Science.gov (United States)

    Weng, Falu; Liu, Mingxin; Mao, Weijie; Ding, Yuanchun; Liu, Feifei

    2018-05-10

    The problem of sampled-data-based vibration control for structural systems with finite-time state constraint and sensor outage is investigated in this paper. The objective of designing controllers is to guarantee the stability and anti-disturbance performance of the closed-loop systems while some sensor outages happen. Firstly, based on matrix transformation, the state-space model of structural systems with sensor outages and uncertainties appearing in the mass, damping and stiffness matrices is established. Secondly, by considering most of those earthquakes or strong winds happen in a very short time, and it is often the peak values make the structures damaged, the finite-time stability analysis method is introduced to constrain the state responses in a given time interval, and the H-infinity stability is adopted in the controller design to make sure that the closed-loop system has a prescribed level of disturbance attenuation performance during the whole control process. Furthermore, all stabilization conditions are expressed in the forms of linear matrix inequalities (LMIs), whose feasibility can be easily checked by using the LMI Toolbox. Finally, numerical examples are given to demonstrate the effectiveness of the proposed theorems. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  12. A comparison of availability and outage time of nuclear power plants

    International Nuclear Information System (INIS)

    Nagatomi, Yu; Matsuo, Yuhji; Murakami, Tomoko

    2011-01-01

    Japan has recently been urged to implement measures to increase availability for nuclear power plants in order to address energy security and greenhouse gas emission cuts. The average availability for Japan's nuclear power plants in 2009 rose from 58.0% in 2008 to 64.7%, still below levels in other major nuclear power generation countries including South Korea and the United States. Some major foreign nuclear power generation countries have kept their availability for nuclear plants at high levels at or above 90% since 1990, while others including the United States and South Korea have raised their respective factors since 2000 following the 1990s when their factors were close to the Japanese level. The latter group made ambitious efforts to raise these factors. In considering specific measures to effectively utilize existing nuclear reactors, Japan should take full account of these overseas efforts and promote discussions on overall Japanese nuclear energy and safety approaches. (author)

  13. The costs of power outages: A case study from Cyprus

    International Nuclear Information System (INIS)

    Zachariadis, Theodoros; Poullikkas, Andreas

    2012-01-01

    We study the costs of electricity disruptions in Cyprus, which suffered severe power shortages in summer 2011 after an explosion that destroyed 60% of its power generating capacity. We employ both economic and engineering approaches to assess these costs. Among other calculations, we provide estimates of the value of lost load by economic sector and the hourly value of electricity by season and type of day. The results of two economic methods employed to assess welfare losses differ largely, indicating that the assessment of outage costs is associated with many uncertainties. Our calculations show that the emergency actions taken by national energy authorities in response to that accident, though not necessarily optimal, have generally been appropriate and in line with international best practices: the additional costs incurred due to these measures are lower than the economic losses avoided thanks to these actions. Preferential treatment of specific consumer types in the case of repeated power outages remains an open policy question. - Highlights: ► We evaluate the response of energy authorities to a sudden electricity crisis. ► We combine two top-down economic methods and a bottom-up engineering approach. ► We estimate the value of lost electricity by hour, day type and season. ► The response of energy authorities turned out to be effective. ► Costs of emergency actions were lower than the economic losses avoided.

  14. Design data and safety features of commercial nuclear power plants including cumulative index for Volumes I--VI

    International Nuclear Information System (INIS)

    Heddleson, F.A.

    1977-01-01

    Design data, safety features, and site characteristics are summarized for 12 nuclear power units in 6 power stations in the United States. Six pages of data are presented for each station, consisting of thermal-hydraulic and nuclear factors, containment features, emergency-core-cooling systems, site features, circulating water system data, and miscellaneous factors. In addition, an aerial perspective is presented for each plant. This volume covers plants with docket numbers 50-553 through 50-569 (Phipps Bend, Black Fox, Yellow Creek, and NEP) and two earlier plants not previously reported--Hope Creek (50-354, 50-355) and WPPSS 1 and 4 (50-460, 50-513). Indexes for this volume and the five earlier volumes are presented in three forms--by docket number, by plant name, and by participating utility

  15. Density and volume measurements of reprocessing plant feed

    International Nuclear Information System (INIS)

    Platzer, R.; Carrier, M.; Neuilly, M.; Dedaldechamp, P.

    1985-05-01

    A theoretical study of the phenomenon of gas bubbles formation within a liquid led to an adaptation of the differential pressure bubbling technique for the measurement of liquid levels and densities in tanks. Experiments, carried out on a 800 liters tank with water and uranyl nitrate solutions had the double aim to study the precision attainable on volume and density measurements and to design a method for corrections of influencing factors. In parallel, procedures for transfer of known volumes through the use of siphons and for tank calibration by liquid level measurement are also investigated. The paper presents the first results obtained so far and the conclusions to be drawn for the elaboration of calibration and exploitation procedures suitables for use in reprocessing plants. The demonstration to transfer mass of solution with an accuracy of 0.1% is made [fr

  16. SEPRA - shutdown PSA for the OLKILUOTO nuclear power plant

    International Nuclear Information System (INIS)

    Himanen, R.

    1995-01-01

    The utility TVO has extended the PSA study to the analysis of refueling, shutdown and startup. The Shutdown Event PRA (SEPRA) was reported to the authority in September 1992. The study consists of the analysis of leaks and loss of decay heat removal in the planned shutdown conditions. Special studies were performed for the cold pressurization, for local criticality events, for heavy load transport and for the transients during startup and shutdown. A remarkable effort was put to identify risks, i.e. to the qualitative analysis. The regular preventive maintenance tasks in the refueling outages were analyzed and the important tasks were selected for further studies. Besides the severe core damage risk the utility was interested in less grave consequences, e.g. the economic risks, causing significant extension of outages. The plant specific screening of initiators consisted of a study on the incident history and of interviewing the plant personnel on selected tasks. A number of thermohydraulic calculations were carried out to support the analysis of accident sequences. The operator actions after an initiating event were verified with the operating staff. The annual core damage risk from the refueling outage is about one forth of the total annual risk. The modifications decreased significantly the core damage frequency. It is foreseen that the SEPRA will form a basis of the procedure enhancement for the low power states. (author) 5 figs., 1 tab., 10 refs

  17. Studies of safety and critical work situations in nuclear power plants: A human factors perspective

    International Nuclear Information System (INIS)

    Jacobsson Kecklund, L.

    1998-05-01

    The purpose of this thesis was to develop and apply different approaches for analyzing safety in critical work situations in real work settings in nuclear power plants, and also to identify safety enhancing measures by using the framework of interaction between human, organizational and technical subsystems. A Cognitive Psychology as well as a Stress Psychology framework was used. All studies were related to the annual outage operational state where the need for coping with many infrequent tasks, often carried out under high time pressure, puts great strain on the staff and organisation of the plant. In three studies the natural variations in the plant state, normal operation and annual outage operation, were used to explore human performance, work-related factors as well as coping and the operators' own resources and the relationship between them. In the annual outage condition high work demands, decreased sleepiness at night shift, more errors and less satisfaction with work performance quality was reported by maintenance as well as by control room operators. A relationship between high work demands and more organizational problems and reports of more frequent human errors and lower satisfactions with work performance quality was also identified in the annual outage condition. Moreover, a relationship between increased sleepiness during night shift, more frequent use of coping strategies and a higher frequency of human errors was reported. In two studies the Event and Barrier Function Model was applied to analyze the safety of barrier function systems inserted into work process sequences to protect the systems from the negative consequences of failures and errors. The model was also used to assess safety in relation to a technical and organizational change. The last study addressed changes in work performance and work-related factors in relation to a technical and organizational change of a safety significant work process involving increased automation and new

  18. Candu Energy's Aging and Obsolescence Program and its Application to Operating Facilities and New Plant Design

    International Nuclear Information System (INIS)

    Dam, R.; Gold, R.; McCrea, L.

    2012-01-01

    While plant aging is inevitable, predictable and 'graceful 'aging' behavior can be achieved through the implementation of a comprehensive and integrated Plant Life Management (PLiM) program. Despite organizations like the IAEA and INPO placing more emphasis on equipment reliability, there is still a lack of completely integrated programs in the industry as evidenced by: - Piece-meal, often crisis-driven, implementation comprising many different, partial solutions; - Duplication of effort often seen when different groups work in 'silos'. A strategy which fits with existing plant processes and programs, and which coordinates a broad range of equipment reliability activities is key to achieving the desired results. An example of such a program is the Aging and Obsolescence Program (AOP). AOP follows application of INPO AP-913 guidance for equipment reliability. The program is augmented to include single point vulnerability identification, unified approach to short and long lived components, risk management, spare parts management, and the identification and resolution of obsolescence issues. The systematic nature of the program provides the needed foundation to old and new stations alike. For existing operating stations some of the key uses include outage interval extension, reduced forced outages, and/or outage time reduction, any of which can translate into improving plant performance, competitiveness, and significant dollars saved. Program elements applied to new plant design are commensurate with the industry direction to 'design for reliability', and has allowed Candu Energy to learn and to improve upon what it can offer to operating stations. This paper intends to describe the basic elements of Candu Energy's Aging and Obsolescence Program and will share some of the experience having applied it to existing operating stations, consider applications to support expanding regulatory requirements, and describe the integration into the design of new plants, promoting

  19. Loss of benefits resulting from nuclear power plant outages. Volume 2. Appendixes

    International Nuclear Information System (INIS)

    Buehring, W.A.; Peerenboom, J.P.

    1982-03-01

    Appendices are presented which contain information concerning the loss of benefits resulting from a hypothetical derating or shutdown of Zion-1, Zion-2, Oconee-1, Oconee-2, Oconee-3, Prairie Island-1, Prairie Island-2, Browns Ferry-1, Browns Ferry-2, and Browns Ferry-3 reactors; review of the General Accounting Office's analysis of the economic impact of closing the Indian Point-1, Indian Point-2, and Indian Point-3 reactors; and review of the General Accounting Office's analysis of the financial effects of the Three Mile Island-2 reactor accident

  20. Consequences of long-term power outages and high electricity prices lasting for months; Konsekvenser av langvarige stroemutfall og hoeye kraftpriser i flere maaneder

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    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. Placement of Synchronized Measurements for Power System Observability during Cascaded Outages

    Science.gov (United States)

    Thirugnanasambandam, Venkatesh; Jain, Trapti

    2017-11-01

    Cascaded outages often result in power system islanding followed by a blackout and therefore considered as a severe disturbance. Maintaining the observability of each island may help in taking proper control actions to preserve the stability of individual islands thus, averting system collapse. With this intent, a strategy for placement of synchronized measurements, which can be obtained from phasor measurement units (PMU), has been proposed in this paper to keep the system observable during cascaded outages also. Since, all the cascaded failures may not lead to islanding situations, therefore, failures leading to islanding as well as non-islanding situations have been considered. A topology based algorithm has been developed to identify the islanding/non-islanding condition created by a particular cascaded event. Additional contingencies such as single line loss and single PMU failure have also been considered after the occurrence of cascaded events. The proposed method is further extended to incorporate the measurement redundancy, which is desirable for a reliable state estimation. The proposed scheme is tested on IEEE 14-bus, IEEE 30-bus and a practical Indian 246-bus networks. The numerical results ensure the observability of the power system under system intact as well as during cascaded islanding and non-islanding disturbances.

  2. 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.

  3. Safety and reliability. V. 1. Proceedings

    International Nuclear Information System (INIS)

    Soares, C.G.

    1997-01-01

    Proceedings of a 1997 conference on industrial safety and reliability are reported. The first volume looks at risk management, probabilistic safety assessment and management styles in various industrial settings, including nuclear power plants. The second volume addresses safety and reliability in the offshore and transport industries, focusing on the role of staff training and appropriate maintenance routines to effectively reduce accidents and outages. (UK)

  4. Benchmarking visit at the Braidwood nuclear power plant. Report no. 311

    International Nuclear Information System (INIS)

    Bataille, C.; Schieber, C.; Faure, J.L.; Valendru, N.

    2010-01-01

    At the request of the French utility EDF, CEPN - ISOE European Technical Center - organized a benchmarking visit at the Braidwood nuclear power plant in the United States of America, Illinois. The mission took place from 20 to 22 October 2009. The French team was composed of two representatives of EDF and two representatives of CEPN. The first part of the mission allowed discussing the general organization and management of radiation protection in the Braidwood station, especially during outages. The second part was mainly focused on two peculiar topics that EDF is currently interested in: the radiation protection training of RP specialists and exposed workers and the RP instrumentation available in the plant. This benchmarking visit allowed underlining the following points. Radiation protection benefits from an important consideration in the daily running of the Braidwood plant. In particular, during outages, a strong RP organization is implemented. Thus, during the preparation period, a detailed 'RP Outage Preparation Checklist' is established: it includes more than 275 tasks and allows ensuring that every RP item is taken into account. During outages realization, the RP Department relies on 12 hour-shifts covering both day and night. Finally, the RP Department ensures a permanent presence in the Outage Control Center: it is represented by a 'superintendent', which is the hierarchical level just under the radiation protection manager. Several comments can be proposed on the structure and the roles of the RP Department. From a first view, the RP personnel can appear quite numerous for a 2-unit plant compared to the situation in EDF plants. However, RP specialists do not have the same roles in Braidwood as in EDF units. Indeed, in Braidwood, the RP staff deals with any activity related to radiation protection including decontamination and shielding; in EDF plants, RP specialists do not manage these last two activities but cover industrial risks. The Braidwood RP

  5. Quality planning for major plant design modifications

    International Nuclear Information System (INIS)

    Dulee, R.J.

    1988-01-01

    This paper reviews the approach and activities undertaken by Public Service Electric and Gas Company's (PSE and G's) nuclear quality assurance (QA) department to support major plant design modifications conducted during refueling outages at Salem Generating Station. It includes the planning and implementation of quality plans developed to provide both QA and quality control (QC) coverage of modification performed by contracted service organizations

  6. The System 80+ Standard Plant design control document. Volume 20

    International Nuclear Information System (INIS)

    1997-01-01

    This Design Control Document (DCD) is a repository of information comprising the System 80+trademark Standard Plant Design. The DCD also provides that design-related information to be incorporated by reference in the design certification rule for the System 80+ Standard Plant Design. Applicants for a combined license pursuant to 10 CFR 52 must ensure that the final Design Certification Rule and the associated Statements of Consideration are used when making all licensing decisions relevant to the System 80+ Standard Plant Design. The Design Control Document contains the DCD introduction, The Certified Design Material (CDM) [i.e., ''Tier 1''] and the Approved Design Material (ADM) [i.e., ''Tier 2''] for the System 80+ Standard Plant Design. The CDM includes the following sections: (1) Introductory material; (2) Certified Design Material for System 80+ systems and structures; (3) Certified Design Material for non-system-based aspects of the System 80+ Certified design; (4) Interface requirements; and (5) Site parameters. The ADM, to the extent applicable for the System 80+ Standard Plant Design, includes: (1) the information required for the final safety analysis report under 20 CFR 50.34; (2) other relevant information required by 10 CFR 52.47; and (3) emergency operations guidelines. This volume contains 2 technical specifications bases as part of Appendix 16 A Tech Spec Bases. They are TS B3.8 Electrical Power Technical Systems Bases and TS B3.9 Refueling Operations Bases. All 3 parts of section 17 (QA) and all 10 parts of section 18 (Human Factors) of the ADM Design and Analysis are contained in this volume. Topics covered in section 17 are: design phase QA; operations phase QA; and design phase reliability assurance. Topics covered by section 18 are: design team organization; design goals; design process; functional task analysis; control room configuration; information presentation; control and monitoring; verification and validation; and review documents

  7. Primary water chemistry improvement for radiation exposure reduction at Japanese PWR Plants

    Energy Technology Data Exchange (ETDEWEB)

    Nishizawa, Eiichi [Omiya Technical Institute, Saitama-ken (Japan)

    1995-03-01

    Radiation exposure during the refueling outages at Japanese Pressurized Water Reactor (PWR) Plants has been gradually decreased through continuous efforts keeping the radiation dose rates at relatively low level. The improvement of primary water chemistry in respect to reduction of the radiation sources appears as one of the most important contributions to the achieved results and can be classified by the plant operation conditions as follows

  8. Reduction of radiation exposure in Japanese BWR Nuclear Power Plants

    International Nuclear Information System (INIS)

    Morikawa, Yoshitake

    1995-01-01

    The reduction of occupational exposure to radiation during the annual inspection and maintenance outages of Japanese boiling water reactors (BWR) is one of the most important objectives for stable and reliable operation. It was shown that this radiation exposure is caused by radionuclides, such as Co-60, Co-58 and Mn-54 which are produced from the metal elements Co, Ni, and Fe present in the corrosion products of structural materials that had been irradiated by neutrons. Therefore, to reduce radiation sources and exposures in Japanese BWRs, attempts have been reinforced to remove corrosion products and activated corrosion products from the primary coolant system. This paper describes the progress of the application of these measures to Japanese BWRs. Most Japanese BWR-4 and BWR-5 type nuclear power plants started their commercial operations during the 1970s. With the elapse of time during operations, a problem came to the forefront, namely that occupational radiation exposure during plant outages gradually increased, which obstructed the smooth running of inspections and maintenance work. To overcome this problem, extensive studies to derive effective countermeasures for radiation exposure reduction were undertaken, based on the evaluation of the plants operation data

  9. Reduction of radiation exposure in Japanese BWR Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, Yoshitake [ISOGO Nuclear Engineering Center, Yokohama (Japan)

    1995-03-01

    The reduction of occupational exposure to radiation during the annual inspection and maintenance outages of Japanese boiling water reactors (BWR) is one of the most important objectives for stable and reliable operation. It was shown that this radiation exposure is caused by radionuclides, such as Co-60, Co-58 and Mn-54 which are produced from the metal elements Co, Ni, and Fe present in the corrosion products of structural materials that had been irradiated by neutrons. Therefore, to reduce radiation sources and exposures in Japanese BWRs, attempts have been reinforced to remove corrosion products and activated corrosion products from the primary coolant system. This paper describes the progress of the application of these measures to Japanese BWRs. Most Japanese BWR-4 and BWR-5 type nuclear power plants started their commercial operations during the 1970s. With the elapse of time during operations, a problem came to the forefront, namely that occupational radiation exposure during plant outages gradually increased, which obstructed the smooth running of inspections and maintenance work. To overcome this problem, extensive studies to derive effective countermeasures for radiation exposure reduction were undertaken, based on the evaluation of the plants operation data.

  10. An Efficient Simulation Scheme of the Outage Probability with Co-Channel Interference

    KAUST Repository

    Rached, Nadhir B.

    2016-03-28

    © 2015 IEEE. The outage probability (OP) of the signal-to-interference-plus-noise ratio (SINR) is an important metric used to evaluate the performance of wireless communication systems operating over fading channels. One major difficulty toward assessing the OP is that, in most of the realistic scenarios, closed-form expressions cannot be derived. This is for instance the case of Log-normal fading environments, in which evaluating the OP of the SINR amounts to computing the probability that a sum of correlated Log-normal variates exceeds a given threshold. Since such a probability is not known to admit a closed-form expression, it has thus far been evaluated by several approximation techniques, the accuracies of which are unfortunately not guaranteed in the interesting region of small outage probabilities. For these regions, simulation techniques based on variance reduction algorithms can represent a good alternative, being well-recognized to be quick and highly accurate for estimating rare event probabilities. This constitutes the major motivation behind our work. More specifically, we propose an efficient importance sampling approach which is based on a covariance matrix scaling technique and illustrate its computational gain over naive Monte Carlo simulations through some selected simulation results.

  11. Barnwell Nuclear Fuels Plant applicability study. Volume III. Appendices

    International Nuclear Information System (INIS)

    1978-03-01

    Volume III suppliees supporting information to assist Congress in making a decision on the optimum utilization of the Barnwell Nuclear Fuels Plant. Included are applicable fuel cycle policies; properties of reference fuels; description and evaluation of alternative operational (flue cycle) modes; description and evaluation of safeguards systems and techniques; description and evaluation of spiking technology; waste and waste solidification evaluation; and Department of Energy programs relating to nonproliferation

  12. The impact of technical specification surveillance requirements and allowable outage times on plant availability

    International Nuclear Information System (INIS)

    Webster, S.A.; Finnicum, D.J.

    1985-01-01

    Surveillances required to be conducted by a plant's Technical Specifications have resulted in plant shutdowns and lost availability. This paper looks at shutdowns which have occurred due to required surveillance testing and insufficient repair time allowed by Technical Specifications. A loss of plant availability of almost 3% per plant year was found for U.S. pressurized water reactors during the five year period, 1979 to 1984. This figure excludes major problems which required plant shutdown whether or not mandated by the Technical Specifications. In addition to their affect on availability, such shutdowns can add to the challenges to plant safety systems and can affect plant aging by increasing the thermal cycles on plant components

  13. Evaluation of operational safety at Babcock and Wilcox Plants: Volume 2, Thermal-hydraulic results

    International Nuclear Information System (INIS)

    Wheatley, P.D.; Davis, C.B.; Callow, R.A.; Fletcher, C.D.; Dobbe, C.A.; Beelman, R.J.

    1987-11-01

    The Nuclear Regulatory Commission has initiated a research program to develop a methodology to assess the operational performance of Babcock and Wilcox plants and to apply this methodology on a trial basis. The methodology developed for analyzing Babcock and Wilcox plants integrated methods used in both thermal-hydraulics and human factors and compared results with information used in the assessment of risk. The integrated methodology involved an evaluation of a selected plant for each pressurized water reactor vendor during a limited number of transients. A plant was selected to represent each vendor, and three transients were identified for analysis. The plants were Oconee Unit 1 for Babcock and Wilcox, H.B. Robinson Unit 2 for Westinghouse, and Calvert Cliffs Unit 1 for Combustion Engineering. The three transients were a complete loss of all feedwater, a small-break loss-of-coolant accident, and a steam-generator overfill with auxiliary feedwater. Included in the integrated methodology was an assessment of the thermal-hydraulic behavior, including event timing, of the plants during the three transients. Thermal-hydraulic results are presented in this volume (Volume 2) of the report. 26 refs., 30 figs., 7 tabs

  14. Nonparametric Tree-Based Predictive Modeling of Storm Outages on an Electric Distribution Network.

    Science.gov (United States)

    He, Jichao; Wanik, David W; Hartman, Brian M; Anagnostou, Emmanouil N; Astitha, Marina; Frediani, Maria E B

    2017-03-01

    This article compares two nonparametric tree-based models, quantile regression forests (QRF) and Bayesian additive regression trees (BART), for predicting storm outages on an electric distribution network in Connecticut, USA. We evaluated point estimates and prediction intervals of outage predictions for both models using high-resolution weather, infrastructure, and land use data for 89 storm events (including hurricanes, blizzards, and thunderstorms). We found that spatially BART predicted more accurate point estimates than QRF. However, QRF produced better prediction intervals for high spatial resolutions (2-km grid cells and towns), while BART predictions aggregated to coarser resolutions (divisions and service territory) more effectively. We also found that the predictive accuracy was dependent on the season (e.g., tree-leaf condition, storm characteristics), and that the predictions were most accurate for winter storms. Given the merits of each individual model, we suggest that BART and QRF be implemented together to show the complete picture of a storm's potential impact on the electric distribution network, which would allow for a utility to make better decisions about allocating prestorm resources. © 2016 Society for Risk Analysis.

  15. Fast Outage Probability Simulation for FSO Links with a Generalized Pointing Error Model

    KAUST Repository

    Ben Issaid, Chaouki

    2017-02-07

    Over the past few years, free-space optical (FSO) communication has gained significant attention. In fact, FSO can provide cost-effective and unlicensed links, with high-bandwidth capacity and low error rate, making it an exciting alternative to traditional wireless radio-frequency communication systems. However, the system performance is affected not only by the presence of atmospheric turbulences, which occur due to random fluctuations in the air refractive index but also by the existence of pointing errors. Metrics, such as the outage probability which quantifies the probability that the instantaneous signal-to-noise ratio is smaller than a given threshold, can be used to analyze the performance of this system. In this work, we consider weak and strong turbulence regimes, and we study the outage probability of an FSO communication system under a generalized pointing error model with both a nonzero boresight component and different horizontal and vertical jitter effects. More specifically, we use an importance sampling approach which is based on the exponential twisting technique to offer fast and accurate results.

  16. Outage performance of opportunistic two-way amplify-and-forward relaying with outdated channel state information

    KAUST Repository

    Hwang, Kyusung; Ju, Minchul; Alouini, Mohamed-Slim

    2013-01-01

    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

  17. Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    Volume 1 is comprised of chapters on: background and description; environmental impacts of add-on gaseous diffusion plant; unavoidable adverse environmental effects; alternatives; relationship between short-term uses and long-term productivity; relationship of program to land-use plans, policies, and controls; irreversible and irretrievable commitments of resources; cost-benefit analysis; and response to comment letters. (LK)

  18. Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 1

    International Nuclear Information System (INIS)

    1977-09-01

    Volume 1 is comprised of chapters on: background and description; environmental impacts of add-on gaseous diffusion plant; unavoidable adverse environmental effects; alternatives; relationship between short-term uses and long-term productivity; relationship of program to land-use plans, policies, and controls; irreversible and irretrievable commitments of resources; cost-benefit analysis; and response to comment letters

  19. Development of an Agent Based Model to Estimate and Reduce Time to Restoration of Storm Induced Power Outages

    Science.gov (United States)

    Walsh, T.; Layton, T.; Mellor, J. E.

    2017-12-01

    Storm damage to the electric grid impacts 23 million electric utility customers and costs US consumers $119 billion annually. Current restoration techniques rely on the past experiences of emergency managers. There are few analytical simulation and prediction tools available for utility managers to optimize storm recovery and decrease consumer cost, lost revenue and restoration time. We developed an agent based model (ABM) for storm recovery in Connecticut. An ABM is a computer modeling technique comprised of agents who are given certain behavioral rules and operate in a given environment. It allows the user to simulate complex systems by varying user-defined parameters to study emergent, unpredicted behavior. The ABM incorporates the road network and electric utility grid for the state, is validated using actual storm event recoveries and utilizes the Dijkstra routing algorithm to determine the best path for repair crews to travel between outages. The ABM has benefits for both researchers and utility managers. It can simulate complex system dynamics, rank variable importance, find tipping points that could significantly reduce restoration time or costs and test a broad range of scenarios. It is a modular, scalable and adaptable technique that can simulate scenarios in silico to inform emergency managers before and during storm events to optimize restoration strategies and better manage expectations of when power will be restored. Results indicate that total restoration time is strongly dependent on the number of crews. However, there is a threshold whereby more crews will not decrease the restoration time, which depends on the total number of outages. The addition of outside crews is more beneficial for storms with a higher number of outages. The time to restoration increases linearly with increasing repair time, while the travel speed has little overall effect on total restoration time. Crews traveling to the nearest outage reduces the total restoration time

  20. 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

    2016-02-26

    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.

  1. The impact of acid soil volume of reclaimed minespoils on plant growth in minilysimeters

    International Nuclear Information System (INIS)

    Shahandeh, H.; Hossner, L.R.; Birkhead, J.A.

    1996-01-01

    Limited data are available to assess the influence of randomly distributed acid soil, produced from acid forming materials (AFM), on growth and productivity of crops. This study evaluated the effect of amount and volume of acid soil on the growth of an acid tolerant plant (Coastal bermudga grass, Cynodon dactylon, L.) and an acid intolerant plant (Yuchi arrowleaf clover, Trifolium vesiculosum, Savi) in greenhouse lysimeters. Acid soil (pH=2.5) volumes up to 20% for Yuchi arrowleaf clover and up to 40% for Coastal bermuda grass did not significantly decrease dry matter yield. Concentrations of Al and Mn in plant tissue of clover and bermudagrass were below the toxicity level. In the presence of randomly distributed acid soil, plant roots continued to elongate in non-acid soil, by evading localized areas of low soil pH. These results suggest that the federally mandated zero tolerance for AFM in the top 1.2 m of reclaimed lands may not be reasonable. 18 refs., 7 figs., 2 tabs

  2. Standard technical specifications: Combustion engineering plants. Volume 3, Revision 1: Bases (Sections 3.4--3.9)

    International Nuclear Information System (INIS)

    1995-04-01

    This report documents the results of the combined effort of the NRC and the industry to produce improved Standard Technical Specifications (STS), Revision 1 for Combustion Engineering Plants. The changes reflected in Revision 1 resulted from the experience gained from license amendment applications to convert to these improved STS or to adopt partial improvements to existing technical specifications. This NUREG is the result of extensive public technical meetings and discussions between the Nuclear Regulatory Commission (NRC) staff and various nuclear power plant licensees, Nuclear Steam Supply System (NSSS) Owners Groups, NSSS vendors, and the Nuclear Energy Institute (NEI). The improved STS were developed based on the criteria in the Final Commission Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors, dated July 22, 1993. The improved STS will be used as the basis for individual nuclear power plant licensees to develop improved plant-specific technical specifications. This report contains three volumes. Volume 1 contains the Specifications for all chapters and sections of the improved STS. Volume 2 contains the Bases for Chapters 2.0 and 3.0, and Sections 3.1--3.3 of the improved STS Volume 3 contains the Bases for Sections 3.4--3.9 of the improved STS

  3. Plant O & M: taking the long view

    Energy Technology Data Exchange (ETDEWEB)

    Schimmoller, B.K.

    2000-02-01

    Taking a long view with respect to power generating assets involves establishing an asset's current competitiveness, determining where it needs to be to remain competitive in the future, and then making the necessary operating and maintenance modifications to get there. The Panther Creek Energy Facility - a Bechtel-designed 83 MW Pyroflow circulating fluidized bed boiler plant in Nesquehoning, PA, managed by Panther Creek Partners (a joint venture between Constellation Power and Ahlstrom Development) and maintained and operated by Constellation Operating Services - provides an excellent example. Here after, a 35-day outage, the outage interval was investigated. OEMs and service provides are increasingly shifting to work with the powerplant instead of for it. TVA for example initially focused on major maintenance and capital ipmrovement projects but subsequently extended to smaller O & M activities. A strategy for space parts needs careful consideration, particularly for nuclear power plants. Several nuclear utilities are investigating inventory management solutions from Wesco. Component obsolescence is another important issue again especially for nuclear utilities. Solutions being found in the nuclear industry will benefit the entire power generation industry. 3 refs., 2 figs., 1 tab., 3 photos.

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

    Science.gov (United States)

    2012-10-17

    ... telephone subscriptions in the United States were users of interconnected VoIP providers--an increase of 21... Commission's Rules Regarding Outage Reporting to Interconnected Voice Over Internet Protocol Service Providers and Broadband Internet Service Providers AGENCY: Federal Communications Commission. ACTION: Final...

  5. Outage performance improvement by state of the art reactor stud tensioning

    International Nuclear Information System (INIS)

    Oehler, Horst Werner; Vervliet, Herman

    2006-01-01

    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

  6. Surrogate Plant Data Base : Volume 2. Appendix C : Facilities Planning Baseline Data

    Science.gov (United States)

    1983-05-01

    This four volume report consists of a data base describing "surrogate" automobile and truck manufacturing plants developed as part of a methodology for evaluating capital investment requirements in new manufacturing facilities to build new fleets of ...

  7. Organizational analysis and safety for utilities with nuclear power plants: an organizational overview. Volume 1. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Osborn, R.N.; Olson, J.; Sommers, P.E.; McLaughlin, S.D.; Jackson, M.S.; Scott, W.G.; Connor, P.E.

    1983-08-01

    This two-volume report presents the results of initial research on the feasibility of applying organizational factors in nuclear power plant (NPP) safety assessment. A model is introduced for the purposes of organizing the literature review and showing key relationships among identified organizational factors and nuclear power plant safety. Volume I of this report contains an overview of the literature, a discussion of available safety indicators, and a series of recommendations for more systematically incorporating organizational analysis into investigations of nuclear power plant safety.

  8. Risk management in Taiwan's nuclear power plants by adopting TIRM-2

    International Nuclear Information System (INIS)

    Chao, Chun-Chang; Kao, Tsu-Mu; Huang, Shian-Hung

    2003-01-01

    The TIRM-2 is the second generation risk monitor developed by INER and TPC. By providing risk indexes such as CDF, LERF, ΔCDF, ΔLERF, importance measurements and availability of safety systems, the TIRM-2 can precisely capture the plant risks and can serve as a better management resource. Examples about how to use TIRM-2 for the risk management are discussed in this paper. For plant at power operation, the TIRM-2 allows the plant staff to change plant configuration directly from the P and I Diagram. For a new plant configuration, only a few minutes will be spent for TIRM-2 to recalculate all the risk indexes. TIRM-2 can also provide risk profile and the associated risk indexes based on a given online maintenance schedule. The risk profile of CDF and LERF with ΔCDF and ΔLERF will help the plant staff with preparing associated information for the applications of risk-informed, performance-based regulation. With the proposed refueling outage schedule, the TIRM-2 can predict status of safety system and risk profile of CDF hourly. All calculations can be done within 40 minutes for a typical 50-days outage schedule. The plant staff and managers can rearrange the maintenance schedule referring to TIRM-2' predicted results and avoiding the plant entering into a potential high-risk situation. With the capability of performing both CDF and LERF calculations, the TIRM-2's will become a very helpful tool in monitoring the risk of different plant status and will provide further information directly for risk-informed applications. (author)

  9. 'EPRI tailored collaboration 2, Crystal River cost and volume reduction program'

    International Nuclear Information System (INIS)

    Genoa, P.H.

    1995-01-01

    During the fall of 1993. Florida Power Corporation joined the EPRI tailored collaboration on the low-level radioactive waste cost and volume reduction. In conjunction with an existing Radwaste Task Force, the EPRI team reviewed past and current waste management practices and developed a prioritized list of opportunities for improvement. In the first quarter of 1994, these opportunities were converted into Action Plans with responsibilities and due dates assigned to support a 60-day refueling outage beginning on April 7, 1994. The Action Plans focussed on: (1) Visible management support in the form of specific plant, department, and worker level radwaste reduction goals. (2) Heightened worker awareness in the form of training (formal and informal), signs, bulletins, and a radwaste awareness video. (3) Material changes from disposable to recyclables, non-incinerables to incinerables, liquid waste processing media replacements and filter use criteria. (4) Work practice changes to reduce valve leaks, reduce contaminated areas, reduce entries to contaminated areas, further segregation of waste streams including 'green is clean' wastes

  10. Use of ABB ADVANT Power for large scale instrumentation and controls replacements in nuclear power plants

    International Nuclear Information System (INIS)

    Pucak, J.L.; Brown, E.M.

    1999-01-01

    One of the major issues facing plants planning for life extension is the viability and feasibility of modernization of a plant's existing I and C systems including the safety systems and the control room. This paper discusses the ABB approach to the implementation of large scale Instrumentation and Controls (I and C) modernization. ABB applies a segmented architecture approach using the ADVANT Power control system to meet the numerous constraints of a major I and C upgrade program. The segmented architecture and how it supports implementation of a complete I and C upgrade either in one outage or in a series of outages is presented. ADVANT Power contains standardized industrial control equipment that is designed to support 1E applications as well as turbine and non-1E process control. This equipment forms the basis for the architecture proposed for future new nuclear plant sales as well as large scale retrofits. (author)

  11. Optimal design of condenser volume in nuclear power plant

    International Nuclear Information System (INIS)

    Zheng Jing; Yan Changqi; Wang Jianjun

    2011-01-01

    The condenser is an important component in the nuclear power plant,whose dimension will influence the economy and the arrangement of the nuclear power plant.In this paper, the calculation model was established according to the design experience. The corresponding codes were also developed. The sensitivity of design parameters which influence the condenser Janume was analyzed. The present optimal design of the condenser, aiming at the volume minimization, was carried out with the self-developed complex-genetic algorithm. The results show that the reference condenser design is far from the best scheme. In addition, the results also verify the feasibility of the complex-genetic algorithm. Furthermore, the results of this paper can provide reference for the design of the condenser. (authors)

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

    KAUST Repository

    Tourki, Kamel; Yang, Hongchuan; Alouini, Mohamed-Slim

    2010-01-01

    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.

  13. 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.

  14. Good practices for cost effective maintenance of nuclear power plants

    International Nuclear Information System (INIS)

    1997-02-01

    This publication is organized around five areas that were identified by the utilities and government organizations who contributed to this report as most important to them. They are: Increasing production through maintenance activities related to improved plant material condition, reduced duration of planned outages, use of on-line maintenance and reduced frequency of forced outages; reducing workload through avoiding unnecessary regulatory burden and using reliability centered maintenance and condition monitoring; improving maintenance processes through better planning and scheduling, use of information management systems, graduated work controls, and appropriate post-maintenance testing; improving productivity through better teamwork, greater sharing of resources, and better radiation management associated with maintenance; measuring performance of maintenance activities through such tools as performance measures and benchmarking. Figs, tabs

  15. Outage analysis for underlay relay-assisted cognitive networks

    KAUST Repository

    Tourki, Kamel; Qaraqe, Khalid A.; Alouini, Mohamed-Slim

    2012-01-01

    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.

  16. 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.

  17. Gentilly 2 steam generators Spring 2000 outage: tubesheet waterlance cleaning and inspection; upper bundle inspection

    International Nuclear Information System (INIS)

    Akeroyd, J.K.; Plante, S.

    2000-01-01

    A review of the secondary side maintenance activities recently completed during the Gentilly 2 Annual Spring 2000 Maintenance Outage. Activities included: 1) Tubesheet intertube waterlance cleaning and visual inspection, 2) First tube support plate, in-bundle visual inspection of the hot leg, and 3) Upper bundle tube support plate visual inspection. A description of the waterlancing and inspection equipment and setup in the RB at Gentilly 2 is provided. Several innovative techniques were successfully employed and yielded savings in critical path duration, labour and personnel radiation dose. These included accessing the SG tubesheet region through one handhole only and sludge removal utilizing the SG blowdown system. Plant personnel judged tubesheet sludge removal successful. Before and after results of the cleaning process along with samples of the visual inspection results are provided. Inspection of the first support plate, which was a repeat of an inspection done in 1997, was conducted along with an in-bundle inspection of the upper tube supports. Results are presented along with a discussion of the implications for future steam generator maintenance. (author)

  18. Savannah River Plant - Project 8980 engineering and design history. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    1957-01-01

    This volume provides an engineering and design history of the 100 area of the Savannah River Plant. This site consisted of five separate production reactor sites, 100-R, P, L, K, and C. The document summarizes work on design of the reactors, support facilities, buildings, siting, etc. for these areas.

  19. Operation of Wastewater Treatment Plants: A Field Study Training Program. Volume I. Second Edition.

    Science.gov (United States)

    California State Univ., Sacramento. Dept. of Civil Engineering.

    This manual was prepared by experienced wastewater collection system workers to provide a home study course to develop new qualified workers and expand the abilities of existing workers. This volume is directed primarily towards entry-level operators and the operators of ponds, package plants, or small treatment plants. Ten chapters examine the…

  20. Loss of benefits resulting from mandated nuclear plant shutdowns

    International Nuclear Information System (INIS)

    Peerenboom, J.P.; Buehring, W.A.

    1982-01-01

    This paper identifies and discusses some of the important consequences of nuclear power plant unavailability, and quantifies a number of technical measures of loss of benefits that result from regulatory actions such as licensing delays and mandated nuclear plant outages. The loss of benefits that accompany such regulatory actions include increased costs of systems generation, increased demand for nonnuclear and often scarce fuels, and reduced system reliability. This paper is based on a series of case studies, supplemented by sensitivity studies, on hypothetical nuclear plant shutdowns. These studies were developed by Argonne in cooperation with four electric utilities

  1. A Short-Term Outage Model of Wind Turbines with Doubly Fed Induction Generators Based on Supervisory Control and Data Acquisition Data

    Directory of Open Access Journals (Sweden)

    Peng Sun

    2016-10-01

    Full Text Available This paper presents a short-term wind turbine (WT outage model based on the data collected from a wind farm supervisory control and data acquisition (SCADA system. Neural networks (NNs are used to establish prediction models of the WT condition parameters that are dependent on environmental conditions such as ambient temperature and wind speed. The prediction error distributions are discussed and used to calculate probabilities of the operation of protection relays (POPRs that were caused by the threshold exceedance of the environmentally sensitive parameters. The POPRs for other condition parameters are based on the setting time of the operation of protection relays. The union probability method is used to integrate the probabilities of operation of each protection relay to predict the WT short term outage probability. The proposed method has been used for real 1.5 MW WTs with doubly fed induction generators (DFIGs. The results show that the proposed method is more effective in WT outage probability prediction than traditional methods.

  2. Worldwide OMEGA and Very Low Frequency (VLF) Transmitter Outages, January to December 1980.

    Science.gov (United States)

    1981-05-01

    WORLDWIDE OMEGA AND VERY LOW FREQUENCY IVLF) TRANSMITTER OUTAGE--ETC, MAY 81 L RZONCA ,’,L.ASSI LED FAA-CT-81-26 FAA-RD- B1 -29 UL7 A-I’ l15FDRL AIO...computer for the time period GBR - Rugby , England (16.00 kHz) January to December 1980. (For the purposes of this report, any downtime NA - Cutler, Maine

  3. Summary of Operating Experience in Swiss Nuclear Power Plants 1999

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-05-15

    The five Swiss nuclear power units produced a net total of 23.6 TWh of electricity in 1999 - not as high as the all-time record (24.45 TWh in 1998), but nonetheless a solid operational performance. The nuclear share in overall electricity production was 35.3%, again lower than the previous year's 40%. In general, plant operation in 1999 was practically as undisturbed and as reliable as in 1998, reflecting the ongoing tradition of careful maintenance that contributes so much to keeping the plants in excellent condition. However, due to exceptional outage activities at Beznau 2 (steam generator replacement) and an unplanned shut-down at Goesgen to replace a hydrogen seal on the main generator, 1999 nuclear production could not match that of the previous year. Also, record hydro power production caused the nuclear share in total electricity production to drop. With the exception of Beznau 2, all refueling and maintenance outages were once again short. The Leibstadt outage lasted 26 days, Goesgen 33 days, Beznau 1 lasted 29 days, Beznau 2 89 days and Muehleberg 27 days. At Goesgen, MOX fuel was loaded for the third time in 1999. Of the 44 freshly-loaded fuel elements, 20 were MOX elements. Non-electrical energy supplies from the Beznau and Goesgen nuclear power plants functioned flawlessly. Beznau fed 143.6 GWh of heat energy into the Refuna district heating system, while Goesgen supplied 169 GWh of process heat to the neighboring Niedergoesgen cardboard factory. At the end of 1999 and the beginning of 2000 all Swiss nuclear units continued to operate flawlessly - notwithstanding the challenges posed by the 'Lothar' storm that hit Western Europe in late December and the so-called Y2K computer bug that threatened to hit shortly afterwards, during the 'millennial' change-over. (authors)

  4. Summary of Operating Experience in Swiss Nuclear Power Plants 1999

    International Nuclear Information System (INIS)

    2000-05-01

    The five Swiss nuclear power units produced a net total of 23.6 TWh of electricity in 1999 - not as high as the all-time record (24.45 TWh in 1998), but nonetheless a solid operational performance. The nuclear share in overall electricity production was 35.3%, again lower than the previous year's 40%. In general, plant operation in 1999 was practically as undisturbed and as reliable as in 1998, reflecting the ongoing tradition of careful maintenance that contributes so much to keeping the plants in excellent condition. However, due to exceptional outage activities at Beznau 2 (steam generator replacement) and an unplanned shut-down at Goesgen to replace a hydrogen seal on the main generator, 1999 nuclear production could not match that of the previous year. Also, record hydro power production caused the nuclear share in total electricity production to drop. With the exception of Beznau 2, all refueling and maintenance outages were once again short. The Leibstadt outage lasted 26 days, Goesgen 33 days, Beznau 1 lasted 29 days, Beznau 2 89 days and Muehleberg 27 days. At Goesgen, MOX fuel was loaded for the third time in 1999. Of the 44 freshly-loaded fuel elements, 20 were MOX elements. Non-electrical energy supplies from the Beznau and Goesgen nuclear power plants functioned flawlessly. Beznau fed 143.6 GWh of heat energy into the Refuna district heating system, while Goesgen supplied 169 GWh of process heat to the neighboring Niedergoesgen cardboard factory. At the end of 1999 and the beginning of 2000 all Swiss nuclear units continued to operate flawlessly - notwithstanding the challenges posed by the 'Lothar' storm that hit Western Europe in late December and the so-called Y2K computer bug that threatened to hit shortly afterwards, during the 'millennial' change-over. (authors)

  5. The different services carried out on valves during nuclear power plants refuelling outages. To the Valves Integrated Service; La gestion de las diferentes actividades en valvulas durante las paradas. Hacia el Servicio Integral de Valvulas

    Energy Technology Data Exchange (ETDEWEB)

    Laporta, J. M.

    2007-07-01

    The different services carried out on valves during nuclear power plants refuelling outages represent overall one of the activities most interfacing with other refuelling tasks because of the large multidisciplinary teams that participate. Different specialized teams are involved on these activities, mainly on testing, diagnostics and maintenance tasks, performed over the same components, in a sequence of processes closely related with common resources. Under such circumstances, coordination between the different teams intervening and the management of administrative documents and activities in close collaboration with the Control Room is fundamental to ensure that the work is performed in the right sequence avoiding downtimes and optimising the critical path. The integration of these processes and the resources involved allow us to undertake the services globally, forming multidisciplinary teams that optimise resources-fundamentally coordination resources and multi-purpose auxiliary resources-maintaining in all cases the necessary degree of specialisation in keeping with the different tasks making up the Valves Integrated Service. (Author)

  6. Use of artificial intelligence in nuclear power plants

    International Nuclear Information System (INIS)

    Uhrig, R.E.

    1990-01-01

    The application of artificial intelligence, in the form of expert systems and neural networks, to the control room activities in a nuclear power plant has the potential to reduce operator error and increase plant safety, reliability, and efficiency. Furthermore, there are a large number of non-operating activities (testing, routine maintenance, outage planning, equipment diagnostics, and fuel management) in which artificial intelligence can increase the efficiency and effectiveness of overall plant and corporate operations. This paper reviews the state-of-the-art of artificial intelligence techniques, specifically, expert systems and neural networks, to nuclear power plants. This paper has reviewed the state-of-the-art of artificial intelligence, specifically expert systems and neural networks that are applied to problems in nuclear power plants

  7. Fundamental Limits of Parallel Optical Wireless Channels: Capacity Results and Outage Formulation

    KAUST Repository

    Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

    2016-01-01

    Multi-channel (MC) optical wireless communication (OWC) systems employing wave-division multiplexing for outdoors free-space optical communications, or multi-user timedivision multiple access for indoors visible-light communications, e.g., can be modeled as parallel channels. Multi-input multioutput OWC systems can also be transformed, possibly with some performance loss, to parallel channels using pre-/postcoding. Studying the performance of such MC-OWC systems requires characterizing the capacity of the underlying parallel channels. In this paper, upper and lower bounds on the capacity of constant parallel OWC channels with a total average intensity constraint are derived. Then, the paper focuses on finding intensity allocations that maximize the lower bounds given channel-state information at the transmitter (CSIT). Due to its nonconvexity, the KKT conditions are used to describe a list of candidate allocations. Instead searching exhaustively for the best solution, low-complexity near-optimal algorithms are proposed. The resulting optimized lower bound nearly coincides with capacity at high signal-to-noise ratio (SNR). Under a quasi-static channel model and in the absence of CSIT, outage probability upper and lower bounds are derived. Those bounds also meet at high SNR, thus characterizing the outage capacity in this regime. Finally, the results are extended to a system with both average and peak intensity constraints.

  8. Fundamental Limits of Parallel Optical Wireless Channels: Capacity Results and Outage Formulation

    KAUST Repository

    Chaaban, Anas

    2016-10-26

    Multi-channel (MC) optical wireless communication (OWC) systems employing wave-division multiplexing for outdoors free-space optical communications, or multi-user timedivision multiple access for indoors visible-light communications, e.g., can be modeled as parallel channels. Multi-input multioutput OWC systems can also be transformed, possibly with some performance loss, to parallel channels using pre-/postcoding. Studying the performance of such MC-OWC systems requires characterizing the capacity of the underlying parallel channels. In this paper, upper and lower bounds on the capacity of constant parallel OWC channels with a total average intensity constraint are derived. Then, the paper focuses on finding intensity allocations that maximize the lower bounds given channel-state information at the transmitter (CSIT). Due to its nonconvexity, the KKT conditions are used to describe a list of candidate allocations. Instead searching exhaustively for the best solution, low-complexity near-optimal algorithms are proposed. The resulting optimized lower bound nearly coincides with capacity at high signal-to-noise ratio (SNR). Under a quasi-static channel model and in the absence of CSIT, outage probability upper and lower bounds are derived. Those bounds also meet at high SNR, thus characterizing the outage capacity in this regime. Finally, the results are extended to a system with both average and peak intensity constraints.

  9. A strategy for improving the profitability of utility power plants in a deregulated industry

    International Nuclear Information System (INIS)

    Reinhart, E.R.

    1996-01-01

    When deregulation of the utility industry becomes a reality in the near future, power plant managers and engineers will face a completely changed business climate. Surviving in a competitive business world will require a dramatic alteration in the way most utility power plants are maintained and upgraded, and in their budget planning. Strategies will have to be developed and implemented that follow the guidelines of good business practices in competitive industries. Some utilities have already started to reduce overhead maintenance costs. Key aspects of their programs can serve as examples to other utilities who want to develop a strategy to improve their operating cost effectiveness. Cost-cutting measures have included development of procedures and data bases that allowed utilities to become independent of original equipment manufacturer (OEM) support and to keep their costs for maintenance, repairs, and replacement of power plant components to a minimum. Also, scheduled power plant outages based on the concepts of reliability-centered maintenance (Smith, 1993), remaining life assessment, and advanced integrity monitors instead of a fixed calendar (Swanekamp, 1996), have allowed utilities to extend the time between some outages by several years. These and other innovative approaches will become critical to power plants operating in the new, deregulated business climate. Examples of actual cost savings are presented here

  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. Valves maintenance management in nuclear power plants

    International Nuclear Information System (INIS)

    Trost, J.

    2001-01-01

    The deregulation of Europe's power market will force nuclear power plant operators to introduce extensive cost-cutting measures in order to be able to compete within this new environment. The optimization of plant outages provides considerable potential for raising plant availability but can also lower operating costs by reducing expenditure on maintenance. Framatome ANP GmbH, in cooperation with plant operators is currently developing new and improved service concepts which can have a major effect on the way in which maintenance will be performed in the future. The concepts encompass optimization of the overall sequence from planning in advance to the individual measures including reduction of the scope of maintenance activities, identification of cost cutting potential and bundling of maintenance activities. (Author)

  12. Organizational analysis and safety for utilities with nuclear power plants: perspectives for organizational assessment. Volume 2

    International Nuclear Information System (INIS)

    Osborn, R.N.; Olson, J.; Sommers, P.E.

    1983-08-01

    This two-volume report presents the results of initial research on the feasibility of applying organizational factors in nuclear power plant (NPP) safety assessment. Volume 1 of this report contains an overview of the literature, a discussion of available safety indicators, and a series of recommendations for more systematically incorporating organizational analysis into investigations of nuclear power plant safety. The six chapters of this volume discuss the major elements in our general approach to safety in the nuclear industry. The chapters include information on organizational design and safety; organizational governance; utility environment and safety related outcomes; assessments by selected federal agencies; review of data sources in the nuclear power industry; and existing safety indicators

  13. The impact of acid soil volume of reclaimed minespoils on plant growth in minilysimeters

    Energy Technology Data Exchange (ETDEWEB)

    Shahandeh, H.; Hossner, L.R.; Birkhead, J.A. [Texas A & M University, College Station, TX (United States). College of Agriculture and Life Science

    1996-06-01

    Limited data are available to assess the influence of randomly distributed acid soil, produced from acid forming materials (AFM), on growth and productivity of crops. This study evaluated the effect of amount and volume of acid soil on the growth of an acid tolerant plant (Coastal bermudga grass, {ital Cynodon dactylon}, L.) and an acid intolerant plant (Yuchi arrowleaf clover, {ital Trifolium vesiculosum}, Savi) in greenhouse lysimeters. Acid soil (pH=2.5) volumes up to 20% for Yuchi arrowleaf clover and up to 40% for Coastal bermuda grass did not significantly decrease dry matter yield. Concentrations of Al and Mn in plant tissue of clover and bermudagrass were below the toxicity level. In the presence of randomly distributed acid soil, plant roots continued to elongate in non-acid soil, by evading localized areas of low soil pH. These results suggest that the federally mandated zero tolerance for AFM in the top 1.2 m of reclaimed lands may not be reasonable. 18 refs., 7 figs., 2 tabs.

  14. Operating experience in nuclear power plants

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The nuclear power plants in the Federal Republic of Germany kept their portion of power supply into the public grid system constant in 1983, compared to 1982. The generation had an absolute increase of 3.6% and amounts now to 65.9 TWh. Particularly mentioned should be the generation of the Grafenrheinfeld Nuclear Power Plant which is holding the 'World Record' with 9.969 TWh. The availability of the plants was generally satisfactory, as far as long-term retrofit measures with long outage periods were not necessary, as it was the case in Brunsbuettel and Wuergassen. The planned retrofit phases have been completed in all power plants. As far as safety is concerned, there was no reason to recommended a change of the present fundamental planning- and operation aspects. (orig.) [de

  15. On the sum of Gamma-Gamma variates with application to the fast outage probability evaluation over fading channels

    KAUST Repository

    Ben Issaid, Chaouki

    2017-04-01

    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 independent and identically distributed 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. We show the accuracy and the efficiency of our approach compared to naive Monte Carlo via some selected numerical simulations.

  16. On the sum of Gamma-Gamma variates with application to the fast outage probability evaluation over fading channels

    KAUST Repository

    Ben Issaid, Chaouki; Rached, Nadhir B.; Kammoun, Abla; Alouini, Mohamed-Slim; Tempone, Raul

    2017-01-01

    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 independent and identically distributed 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. We show the accuracy and the efficiency of our approach compared to naive Monte Carlo via some selected numerical simulations.

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

    Energy Technology Data Exchange (ETDEWEB)

    Durance, D.; Sedman, K. [Bruce Power, Tiverton, Ontario (Canada); Roberts, J. [CANTECH Associates Ltd., Burlington, Ontario (Canada); King, P. [Babcock and Wilcox Canada, Cambridge, Ontario (Canada); Gorman, J. [Dominion Engineering, Reston, VA (United States); Allen, R. [Kinectrics, Inc., Toronto, Ontario (Canada)

    2008-07-01

    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)

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

    International Nuclear Information System (INIS)

    Durance, D.; Sedman, K.; Roberts, J.; King, P.; Gorman, J.; Allen, R.

    2008-01-01

    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)

  19. A Sensitivity Study of Human Errors in Optimizing Surveillance Test Interval (STI) and Allowed Outage Time (AOT) of Standby Safety System

    International Nuclear Information System (INIS)

    Chung, Dae Wook; Shin, Won Ky; You, Young Woo; Yang, Hui Chang

    1998-01-01

    In most cases, the surveillance test intervals (STIs), allowed outage times (AOTS) and testing strategies of safety components in nuclear power plant are prescribed in plant technical specifications. And, in general, it is required that standby safety system shall be redundant (i.e., composed of multiple components) and these components are tested by either staggered test strategy or sequential test strategy. In this study, a linear model is presented to incorporate the effects of human errors associated with test into the evaluation of unavailability. The average unavailabilities of 1/4, 2/4 redundant systems are computed considering human error and testing strategy. The adverse effects of test on system unavailability, such as component wear and test-induced transient have been modelled. The final outcome of this study would be the optimized human error domain from 3-D human error sensitivity analysis by selecting finely classified segment. The results of sensitivity analysis show that the STI and AOT can be optimized provided human error probability is maintained within allowable range. (authors)

  20. Standard technical specifications: Babcock and Wilcox plants. Volume 3, Revision 1: Bases (Sections 3.4--3.9)

    International Nuclear Information System (INIS)

    1995-04-01

    This report documents the results of the combined effort of the NRC and the industry to produce improved Standard Technical Specifications (STS), Revision 1 for Babcock and Wilcox Plants. The changes reflected in Revision 1 resulted from the experience gained from license amendment applications to convert to these improved STS or to adopt partial improvements to existing technical specifications. This NUREG is the result of extensive public technical meetings and discussions between the Nuclear Regulatory Commission (NRC) staff and various nuclear power plant licensees, Nuclear Steam Supply System (NSSS) Owners Groups, NSSS vendors, and the Nuclear Energy Institute (NEI). The improved STS were developed based on the criteria in the Final Commission Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors, dated July 22, 1993. The improved STS will be used as the basis for individual nuclear power plant licensees to develop improved plant-specific technical specifications. This report contains three volumes. Volume 1 contains the Specifications for all chapters and sections of the improved STS. Volume 2 contains the Bases for Chapters 2.0 and 3.0, and Sections 3.1--3.3 of the improved STS. Volume 3 contains the Bases for Sections 3.4--3.9 of the improved STS

  1. Comprehensive Cooling Water Study. Volume 1. Summary of environmental effects, Savannah River Plant. Annual report

    International Nuclear Information System (INIS)

    Gladden, J.B.; Lower, M.W.; Mackey, H.E.; Specht, W.L.; Wilde, E.W.

    1985-07-01

    This volume summarizes the technical content of Volumes II through XI of the annual report. Volume II provides a description of the SRP environment, facilities, and operation, and presents the objectives and design for the CCWS. Volume III presents information on water quality of SRP surface waters. Results of radionuclide and heavy metal transport studies are presented in Volume IV. Volume V contains findings from studies of wetland plant communities. Volume VI presents findings from studies of the lower food chain components of SRP aquatic habitats. The results of fisheries studies are reported in Volume VII. Studies of semi-aquatic vertebrate populations are reported in Volume VIII. Water-fowl utilization of SRP habitats is discussed in Volume IX. The status of endangered species that utilize SRP aquatic habitats is presented in Volume X. The findings from studies of Parr Pond ecosystem are presented in Volume XI

  2. 76 FR 36892 - Proposed Extension of Part 4 of the Commission's Rules Regarding Outage Reporting to...

    Science.gov (United States)

    2011-06-23

    ...: None. Title: Communications Outage Reporting for Interconnected Voice over Internet Protocol Service.... Type of Review: New collection. Respondents: Businesses (Interconnected Voice over Internet Protocol... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 4 [PS Docket No. 11-82; FCC 11-74] Proposed...

  3. Human errors and work performance in a nuclear power plant control room: associations with work-related factors and behavioral coping

    International Nuclear Information System (INIS)

    Kecklund, L.J.; Svenson, O.

    1997-01-01

    The present study investigated the relationships between the operator's appraisal of his own work situation and the quality of his own work performance, as well as self-reported errors in a nuclear power plant control room. In all, 98 control room operators from two nuclear power units filled out a questionnaire and several diaries during two operational conditions, annual outage and normal operation. As expected, the operators reported higher work demands in annual outage as compared to normal operation. In response to the increased demands, the operators reported that they used coping strategies such as increased effort, decreased aspiration level for work performance quality, and increased use of delegation of tasks to others. This way of coping does not reflect less positive motivation for the work during the outage period. Instead, the operators maintain the same positive motivation for their work, and succeed in being more alert during morning and night shifts. However, the operators feel less satisfied with their work result. The operators also perceive the risk of making minor errors as increasing during outage. (Author)

  4. User's guide for PRISM (Plant Risk Status Information Management System) Arkansas Nuclear One-Unit 1: Volume 1, Program for inspectors

    International Nuclear Information System (INIS)

    Campbell, D.J.; Guthrie, V.H.; Kirchner, J.R.; Kirkman, J.Q.; Paula, H.M.; Ellison, B.C.; Dycus, F.M.; Farquharson, J.A.; Flanagan, G.F.

    1988-03-01

    This user's guide is a two-volume document designed to teach NRC inspectors and NRC regulators how to access probabilistic risk assessment information from the two Plant Risk Status Information Management System (PRISIM) programs developed for Arkansas Nuclear One -- Unit One (ANO-1). This document, Volume 1, describes how the PRA information available in Version 1.0 of PRISIM is useful for planning inspections. Using PRISIM, inspectors can quickly access PRA information and use that information to update risk analysis results, reflecting a plant's status at any particular time. Both volumes are stand-alone documents, and each volume presents several sample computer sessions designed to lead the user through a variety of PRISIM applications used to obtain PRA-related information for monitoring and controlling plant risk

  5. Surrogate Plant Data Base : Volume 4. Appendix E : Medium and Heavy Truck Manufacturing

    Science.gov (United States)

    1983-05-01

    This four volume report consists of a data base describing "surrogate" automobile and truck manufacturing plants developed as part of a methodology for evaluating capital investment requirements in new manufacturing facilities to build new fleets of ...

  6. In service inspection of the reactor pressure vessel coolant and moderator nozzles at Atucha 1. 1998/1999 outages

    International Nuclear Information System (INIS)

    Antonaccio, Carlos; Conde, Alberto; Fittipaldi, Andres H.; Maniotti, Jorge; Moliterno, Gabriel E.

    2000-01-01

    During the August 1998 and the August 1999 Atucha 1 outages, two areas were inspected on the Reactor Pressure Vessel: the nozzle inner radii and the nozzle shell welds on all 3 moderator nozzles and all 4 main coolant nozzles. The inspections themselves were carried out by Mitsui Babcock Energy Limited from Scotland. The coordination, maintenance assistant and mounting of the manipulator devices over the nozzles were carried out by NASA personnel. Although it was not the first time the nozzle shell welds were inspected, due to the technologies advances in the ultrasonic field and in the inspection manipulators (magnetic ones), it was possible to inspect more volume than in previous inspections. In the other hand, it was the first time NASA was able to inspect the inner radii. In this last case the mayor problems to inspect them were the nozzles geometry and the small space available to install manipulators. The result of the inspections were: 1) There were no reportable indications at any of the inner radii inspected; 2) The inspection of nozzle to shell welds in main-coolant nozzles R3 and R4 detected flaws (one in each nozzle) which were reported as exceeding the dimensions specified as the acceptance level under Table IWB 3512-1, Section XI of the ASME code. Subsequent analysis requested by NASA and performed by Mitsui Babcock, demonstrated that the flaws were over dimensioned and could be explained as due to 'point' flaws. The analysis was based on theoretical mathematic model and experimental trials. Therefore their dimension were under the acceptance level of the ASME XI code. Although the Mitsui Babcock analysis, and at the same time it was in progress, it was assumed that the flaws were as they were originally presented (exceeding the acceptance level). NASA asked SIEMENS/KWU, the designer of the plant, to perform the fracture assessment according to ASME XI App. A. The assessment shows that the expected crack growth is negligibly small and the safety

  7. Quality assurance program manual for nuclear power plants. Volume I. Policies

    International Nuclear Information System (INIS)

    1976-01-01

    The Consumers Power Company Quality Assurance Program Manual for Nuclear Power Plants consists of policies and procedures which comply with current NRC regulatory requirements and industry codes and standards in effect during the design, procurement, construction, testing, operation, refueling, maintenance, repair and modification activities associated with nuclear power plants. Specific NRC and industry documents that contain the requirements, including the issue dates in effect, are identified in each nuclear power plant's Safety Analysis Report. The requirements established by these documents form the basis for the Consumer Power Quality Assurance Program, which is implemented to control those structures, systems, components and operational safety actions listed in each nuclear power plant's Quality List (Q-List). As additional and revised requirements are issued by the NRC and professional organizations involved in nuclear activities, they will be reviewed for their impact on this manual, and changes will be made where considered necessary. CP Co 1--Consumers Power Company QA Program Topical Report is Volume I of this manual and contains Quality Assurance Program Policies applicable during all phases of nuclear power plant design, construction and operation

  8. Summary of EPRI projects for improving power plant maintenance and maintainability

    International Nuclear Information System (INIS)

    Shugars, H.G.; Poole, D.N.; Pack, R.W.

    1979-01-01

    The Electric Power Research Institute is sponsoring projects to improve power plant maintenance and maintainability. Areas presently being emphasized are improvements in plant design for maintainability, improvements in performing nuclear plant refuelings, and development of on-line monitoring and diagnostic systems for various plant components. The seven projects are reviewed. They are: (1) human factors review of power plant maintainability; (2) refueling outage improvement; (3) on-line monitoring and diagnostics for power plant machinery; (4) acoustic emission and vibrati1on signature analysis of fossil fuel plant components; (5) acoustic monitoring of power plant valves; (6) on-line monitoring and diagnostics for generators; and (7) detection of water induction in steam turbines. Each project contractor and the project manager are listed for reference. 8 references

  9. Evaluation of allowed outage times (AOTS) from a risk and reliability standpoint

    International Nuclear Information System (INIS)

    Vesely, W.E.

    1989-08-01

    This report describes the basic risks associated with allowed outage times (AOTS), defines strategies for selecting the risks to be quantified, and describes how the risks can be quantified. This report provides a basis for risk-based approaches for regulatory and plant implementation. The AOT risk evaluations can be applied to proposed one-time AOT changes, or to permanent changes. The evaluations can also be used to quantify risks associated with present AOTs, and in establishing AOTs from a risk perspective. The report shows that the standard way of calculating AOT risks in probabilistic risk analyses (PRAs) generally is not sufficient when evaluating all the risks associated with an AOT in order to assess its acceptability. The PRA calculates an average AOT risk which includes the frequency at which the AOT is expected to occur. Other risks associated with an AOT include the single downtime risk, which is the risk incurred when (given) the AOT has occurred. The single downtime risk is generally the most applicable risk in determining the acceptability of the AOT. The single downtime risks are generally much larger than the PRA-averaged risk. For more comprehensive evaluations, both risks should be calculated. The report also describes other risks which can be considered, including personnel and economic risks. Finally, the report discusses the detailed evaluations which are involved in calculating AOT risks, including considerations of uncertainty. (author)

  10. Managed maintenance, the next step in power plant maintenance

    International Nuclear Information System (INIS)

    Butterworth, G.; Anderson, T.M.

    1984-01-01

    The Westinghouse Nuclear Services Integration Division managed maintenance services are described. Essential to the management and control of a total plant maintenance programme is the development of a comprehensive maintenance specification. During recent years Westinghouse has jointly developed total plant engineering-based maintenance specifications with a number of utilities. The process employed and the experience to date are described. To efficiently implement the maintenance programme Westinghouse has developed a computer software program specifically designed for day to day use at the power plant by maintenance personnel. This program retains an equipment maintenance history, schedules maintenance activities, issues work orders and performs a number of sophisticated analyses of the maintenance backlog and forecast, equipment failure rates, etc. The functions of this software program are described and details of Westinghouse efforts to support the utilities in reducing outage times through development of predefined outage plans for critical report maintenance activities are given. Also described is the experience gained in the training of specialized maintenance personnel, employing competency-based training techniques and equipment mock-ups, and the benefits experienced, in terms of improved quality and productivity of maintenance performed. The success experienced with these methods has caused Westinghouse to expand the use of these training techniques to the more routine skill areas of power plant maintenance. A significant reduction in the operating costs of nuclear power plants will only be brought about by a significant improvement in the quality of maintenance. Westinghouse intends to effect this change by expanding its international service capabilities and to make major investments in order to promote technological developments in the area of power plant maintenance. (author)

  11. Garigliano nuclear power plant

    International Nuclear Information System (INIS)

    1976-03-01

    During the period under review, the Garigliano power station produced 1,028,77 million kWh with a utilization factor of 73,41% and an availability factor of 85,64%. The disparity between the utilization and availability factors was mainly due to a shutdown of about one and half months owing to lack of staff at the plant. The reasons for nonavailability (14.36%) break down as follows: nuclear reasons 11,49%; conventional reasons 2,81%; other reasons 0,06%. During the period under review, no fuel replacements took place. The plant functioned throughout with a single reactor reticulation pump and resulting maximum available capacity of 150 MWe gross. After the month of August, the plant was operated at levels slightly below the maximum available capacity in order to lengthen the fuel cycle. The total number of outages during the period under review was 11. Since the plant was brought into commercial operation, it has produced 9.226 million kWh

  12. Efficient Outage Probability Evaluation of Diversity Receivers Over Generalized Gamma Channels

    KAUST Repository

    Ben Issaid, Chaouki

    2016-10-01

    In this paper, we are interested in determining the cumulative distribution function of the sum of generalized Gamma in the setting of rare event simulations. To this end, we present an efficient importance sampling estimator. The main result of this work is the bounded relative property of the proposed estimator. This result is used to accurately estimate the outage probability of multibranch maximum ratio combining and equal gain combining diversity receivers over generalized Gamma fading channels. Selected numerical simulations are discussed to show the robustness of our estimator compared to naive Monte Carlo.

  13. Efficient Outage Probability Evaluation of Diversity Receivers Over Generalized Gamma Channels

    KAUST Repository

    Ben Issaid, Chaouki; Alouini, Mohamed-Slim; Tempone, Raul

    2016-01-01

    In this paper, we are interested in determining the cumulative distribution function of the sum of generalized Gamma in the setting of rare event simulations. To this end, we present an efficient importance sampling estimator. The main result of this work is the bounded relative property of the proposed estimator. This result is used to accurately estimate the outage probability of multibranch maximum ratio combining and equal gain combining diversity receivers over generalized Gamma fading channels. Selected numerical simulations are discussed to show the robustness of our estimator compared to naive Monte Carlo.

  14. Power plant fault detection using artificial neural network

    Science.gov (United States)

    Thanakodi, Suresh; Nazar, Nazatul Shiema Moh; Joini, Nur Fazriana; Hidzir, Hidzrin Dayana Mohd; Awira, Mohammad Zulfikar Khairul

    2018-02-01

    The fault that commonly occurs in power plants is due to various factors that affect the system outage. There are many types of faults in power plants such as single line to ground fault, double line to ground fault, and line to line fault. The primary aim of this paper is to diagnose the fault in 14 buses power plants by using an Artificial Neural Network (ANN). The Multilayered Perceptron Network (MLP) that detection trained utilized the offline training methods such as Gradient Descent Backpropagation (GDBP), Levenberg-Marquardt (LM), and Bayesian Regularization (BR). The best method is used to build the Graphical User Interface (GUI). The modelling of 14 buses power plant, network training, and GUI used the MATLAB software.

  15. Wind Power Plant Voltage Stability Evaluation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E.; Zhang, Y. C.

    2014-09-01

    Voltage stability refers to the ability of a power system to maintain steady voltages at all buses in the system after being subjected to a disturbance from a given initial operating condition. Voltage stability depends on a power system's ability to maintain and/or restore equilibrium between load demand and supply. Instability that may result occurs in the form of a progressive fall or rise of voltages of some buses. Possible outcomes of voltage instability are the loss of load in an area or tripped transmission lines and other elements by their protective systems, which may lead to cascading outages. The loss of synchronism of some generators may result from these outages or from operating conditions that violate a synchronous generator's field current limit, or in the case of variable speed wind turbine generator, the current limits of power switches. This paper investigates the impact of wind power plants on power system voltage stability by using synchrophasor measurements.

  16. Engineering and maintenance applied to safety-related valves in nuclear power plants

    International Nuclear Information System (INIS)

    Verdu, M. F.; Perez-Aranda, J.

    2014-01-01

    Nuclear Division in Iberdrola engineering and Construction has a team with extensive experience on engineering and services works related to valves. Also, this team is linked to UNESA as Technical support and Reference Center. Iberdrola engineering and construction experience in nuclear power plants valves, gives effective response to engineering and maintenance works that can be demanded in a nuclear power plant and it requires a high degree of qualification and knowledge both in Operation and Outages. (Author)

  17. Y-12 Plant remedial action Technology Logic Diagram: Volume 3, Technology evaluation data sheets: Part A, Remedial action

    International Nuclear Information System (INIS)

    1994-09-01

    The Y-12 Plant Remedial Action Technology Logic Diagram (TLD) was developed to provide a decision-support tool that relates environmental restoration (ER) problems at the Y-12 Plant to potential technologies that can remediate these problems. The TLD identifies the research, development, demonstration, testing, and evaluation needed for sufficient development of these technologies to allow for technology transfer and application to remedial action (RA) activities. The TLD consists of three volumes. Volume 1 contains an overview of the TLD, an explanation of the program-specific responsibilities, a review of identified technologies, and the rankings of remedial technologies. Volume 2 contains the logic linkages among environmental management goals, environmental problems and the various technologies that have the potential to solve these problems. Volume 3 contains the TLD data sheets. This report is Part A of Volume 3 and contains the Remedial Action section

  18. Y-12 Plant remedial action Technology Logic Diagram: Volume 3, Technology evaluation data sheets: Part A, Remedial action

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-09-01

    The Y-12 Plant Remedial Action Technology Logic Diagram (TLD) was developed to provide a decision-support tool that relates environmental restoration (ER) problems at the Y-12 Plant to potential technologies that can remediate these problems. The TLD identifies the research, development, demonstration, testing, and evaluation needed for sufficient development of these technologies to allow for technology transfer and application to remedial action (RA) activities. The TLD consists of three volumes. Volume 1 contains an overview of the TLD, an explanation of the program-specific responsibilities, a review of identified technologies, and the rankings of remedial technologies. Volume 2 contains the logic linkages among environmental management goals, environmental problems and the various technologies that have the potential to solve these problems. Volume 3 contains the TLD data sheets. This report is Part A of Volume 3 and contains the Remedial Action section.

  19. An Internet of Things Approach to Electrical Power Monitoring and Outage Reporting

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Daniel B [ORNL

    2017-01-01

    The so-called Internet of Things concept has captured much attention recently as ordinary devices are connected to the Internet for monitoring and control purposes. One enabling technology is the proliferation of low-cost, single board computers with built-in network interfaces. Some of these are capable of hosting full-fledged operating systems that provide rich programming environments. Taken together, these features enable inexpensive solutions for even traditional tasks such as the one presented here for electrical power monitoring and outage reporting.

  20. Standard Technical Specifications General Electric plants, BWR/4:Bases (Sections 3.4-3.10). Volume 3, Revision 1

    International Nuclear Information System (INIS)

    1995-04-01

    This report documents the results of the combined effort of the NRC and the industry to produce improved Standard Technical Specifications (STS), Revision 1 for General Electric BWR/4 Plants. The changes reflected in Revision 1 resulted from the experience gained from license amendment applications to convert to these improved STS or to adopt partial improvements to existing technical specifications. This NUREG is the result of extensive public technical meetings and discussions between the Nuclear Regulatory Commission (NRC) staff and various nuclear power plant licensees, Nuclear Steam Supply System (NSSS) Owners Groups, NSSS vendors, and the Nuclear Energy Institute (NEI). The improved STS were developed based on the criteria in the Final Commission Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors, dated July 22, 1993. The improved STS will be used as the basis for individual nuclear power plant licensees to develop improved plant-specific technical specifications. This report contains three volumes. Volume 1 contains the specifications for all chapters and sections of the improved STS. Volume 2 contains he Bases for Chapters 2.0 and 3.0, and Sections 3.1-3.3 of the improved STS. This document, Volume 3, contains the Bases for Sections 3.4-3.10 of the improved STS

  1. Standard Technical Specifications General Electric plants, BWR/4: Bases (Sections 2.0-3.3). Volume 2, Revision 1

    International Nuclear Information System (INIS)

    1995-04-01

    This report documents the results of the combined effort of the NRC and the industry produce improved Standard Technical Specifications (STS), Revision 1 for General Electric BWR/4 Plants. The changes reflected in Revision 1 resulted from the experience gained from license amendment applications to convert to these improved ST or to adopt partial improvements to existing technical specifications. This NUREG is the result of extensive public technical meetings and discussions between the Nuclear Regulatory Commission (NRC) staff and various nuclear power plant licensees, Nuclear Steam Supply System (NSSS) Owners Groups, NSSS vendors, and the Nuclear Energy Institute (NEI). The improved STS were developed based on the criteria in the Final Commission Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors, dated July 22, 1993. The improved STS will be used as the basis for individual nuclear power plant licensees to develop improved plant-specific technical specifications. This report contains three volumes. Volume I contains the Specifications for all chapters and sections of the improved STS. This document, Volume 2, contains the Bases for Chapters 2.0 and 3.0, and Sections 3.1-3.3 of the improved STS. Volume 3 contains the Bases for Sections 3.4-3.10 of the improved STS

  2. On-line valve monitoring at the Ormen Lange gas plant

    Energy Technology Data Exchange (ETDEWEB)

    Greenlees, R.; Hale, S. [Score Atlanta Inc., Kennesaw, Georgia (United States)

    2011-07-01

    The purpose of this presentation is to discuss replacing time and labor intensive nuclear outage activities with on line condition monitoring solutions, primarily the periodic verification of MOV functionality discussed in USNRC Generic Letter 96.05. This regulation requires that MOV age related performance degradations are properly identified and accounted for, causing utilities to have to retest valves periodically for the duration of the plants operating license. AECL designed CANDU reactors have a world class performance and safety record, with typical average annual capacity factors of 90%. The CANDU reactor design has the ability to refuel on line, as a result (a) it can be a challenge scheduling all required valve testing into limited duration outage work windows, (b) at multi unit sites, Unit 0 valves can be difficult to test because they are rarely ever out of service, (c) deuterium-oxide (heavy water) moderator is expensive to manufacture, as a result, effective through valve leakage monitoring is essential. These three factors alone make CANDU sites the most suitable candidates for on line valve monitoring systems. Nuclear industry regulations have been instrumental in the development of 'at the valve' diagnostic systems, but diagnostic testing has not typically been utilized to the same degree in other less regulated industries. However, that trend is changing, and the move toward valve diagnostics and condition monitoring has moved fastest in the offshore oil and gas industry on the Norwegian side of the North Sea. The Ormen Lange plant, located on Nyhamna Island on the west coast of Norway, operated by Shell, is one of the worlds most advanced gas processing plants. A stated maintenance goal for the plant is that 70% of the maintenance budget and spend should be based on the results of on line condition monitoring, utilizing monitoring systems equipped with switch sensing, strain gages, hydraulic and pneumatic pressure transducers and

  3. On-line valve monitoring at the Ormen Lange gas plant

    International Nuclear Information System (INIS)

    Greenlees, R.; Hale, S.

    2011-01-01

    The purpose of this presentation is to discuss replacing time and labor intensive nuclear outage activities with on line condition monitoring solutions, primarily the periodic verification of MOV functionality discussed in USNRC Generic Letter 96.05. This regulation requires that MOV age related performance degradations are properly identified and accounted for, causing utilities to have to retest valves periodically for the duration of the plants operating license. AECL designed CANDU reactors have a world class performance and safety record, with typical average annual capacity factors of 90%. The CANDU reactor design has the ability to refuel on line, as a result (a) it can be a challenge scheduling all required valve testing into limited duration outage work windows, (b) at multi unit sites, Unit 0 valves can be difficult to test because they are rarely ever out of service, (c) deuterium-oxide (heavy water) moderator is expensive to manufacture, as a result, effective through valve leakage monitoring is essential. These three factors alone make CANDU sites the most suitable candidates for on line valve monitoring systems. Nuclear industry regulations have been instrumental in the development of 'at the valve' diagnostic systems, but diagnostic testing has not typically been utilized to the same degree in other less regulated industries. However, that trend is changing, and the move toward valve diagnostics and condition monitoring has moved fastest in the offshore oil and gas industry on the Norwegian side of the North Sea. The Ormen Lange plant, located on Nyhamna Island on the west coast of Norway, operated by Shell, is one of the worlds most advanced gas processing plants. A stated maintenance goal for the plant is that 70% of the maintenance budget and spend should be based on the results of on line condition monitoring, utilizing monitoring systems equipped with switch sensing, strain gages, hydraulic and pneumatic pressure transducers and acoustic leakage

  4. Feedback of operation and maintenance experience into evolutionary plant design (HWRs)

    International Nuclear Information System (INIS)

    Hedges, K.R.; Sanatkumar, A.; Kwon, Oh-Cheol

    1999-01-01

    The process of feeding back operation and maintenance information into the CANDU plant design process has been in constant evolution since the beginning of the CANDU program. The commissioning and operation experience from the first commercial reactors at Pickering A and Bruce A was used extensively in the design of the first generation CANDU 6 Plants. These units have been in operation for 15 years, producing electricity at an average lifetime capacity factor of about 85%. In further advancing the CANDU 6 and 9 design, greater emphasis is placed on enhancements that can reduce operational costs and further improve plant performance by reducing the planned outage time. The plant design has been improved to facilitate maintenance scheduling, equipment isolation, maintenance and post maintenance testing. Individual tasks have been analyzed as well as the interaction between tasks during outages to reduce the down time required and simplify the execution of the work. This results in shorter outages, reduced radioactive dose and reduced costs. The Utilities have continued to play an important role in CANDU 6 Evolution. Specifically; the Korea Utility KEPCO has one of the original four CANDU 6 Plants and three of the most modem. Their feedback to the designers has been very helpful. One of the most important feedback processes is through the CANDU Owners Group, which provides information exchange between members. In India eight PHWRs of 220 MWe capacity are in operation. Four reactors, also of 220 MWe capacity are in advanced stages of construction. Site construction work of two units of 500 MWe PHWRs at Tarapur will be taken up shortly. Over the years, during construction and operation of these power stations, a large amount of experience has been accumulated. Operation and maintenance experience is shared with operating stations by intensive participation of design engineers in Station Operation Review meetings, trouble shooting and root cause analysis of problems

  5. Important aspects for consideration in minimizing plant outage times. Swiss experience in achieving high availability

    International Nuclear Information System (INIS)

    Malcotsis, G.

    1984-01-01

    Operation of Swiss nuclear power plants has not been entirely free of trouble. They have experienced defective fuel elements, steam generator tube damage, excessive vibration of the core components, leakages in the recirculation pump seals and excessive corrosion and erosion in the steam-feedwater plant. Despite these technical problems in the early life of the plants, on overall balance the plants can be considered to have performed exceedingly well. The safety records from more than 40 reactor-years of operation are excellent and, individually and collectively, the capacity factors obtained are among the highest in the world. The problems mentioned have been solved and the plants continue operation with high availabilities. This success can be attributed to the good practices of the utilities with regard to the choice of special design criteria, plant organization, plant operation and plant maintenance, and also to the pragmatic approach of the licensing authorities and their consultants to quality assurance and quality control. The early technical problems encountered, the corresponding solutions adopted and the factors that contributed towards achieving high availabilities in Swiss nuclear power plants are briefly described. (author)

  6. Latina nuclear power plant

    International Nuclear Information System (INIS)

    1976-03-01

    In the period under review, the Latina power plant produced 1009,07 million kWh with a utilization factor of 72% and an availability factor of 80,51%. The disparity between the utilization and availability factors was mainly due to the shutdown of the plant owing to trade union strife. The reasons for non-availability (19,49%) were almost all related to the functioning of the conventional part and the general servicing of the plant (18 September-28 October). During the shutdown for maintenance, an inspection of the steel members and parts of the core stabilizing structure was made in order to check for the familiar oxidation phenomena caused by CO 2 ; the results of the inspection were all satisfactory. Operation of the plant during 1974 was marked by numerous power cutbacks as a result of outages of the steam-raising units (leaks from the manifolds) and main turbines (inspection and repairs to the LP rotors). Since it was first brought into commercial operation, the plant has produced 13,4 thousand million kWh

  7. Research program for seismic qualification of nuclear plant electrical and mechanical equipment. Task 4. Use of fragility in seismic design of nuclear plant equipment. Volume 4

    International Nuclear Information System (INIS)

    Kana, D.D.; Pomerening, D.J.

    1984-08-01

    The Research Program for Seismic Qualification of Nuclear Plant Electrical and Mechanical Equipment has spanned a period of three years and resulted in seven technical summary reports, each of which have covered in detail the findings of different tasks and subtasks, and have been combined into five NUREG/CR volumes. Volume 4 presents study of the use of fragility concepts in the design of nuclear plant equipment and compares the results of state-of-the-art proof testing with fragility testing

  8. 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.

  9. Quantification of risk considering external events on the change of allowed outage time and the preventive maintenance during power operation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, D. J.; Kim, K. Y.; Yang, J. E

    2001-03-01

    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 ({delta}CDF) 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

  10. 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)

    Kang, D. J.; Kim, K. Y.; Yang, J. E.

    2001-03-01

    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

  11. Determination of the sources of the airborne physico-chemical 131I species in a PWR power plant

    International Nuclear Information System (INIS)

    Deuber, H.; Wilhelm, J.G.

    1978-01-01

    In a 1300 MWE PWR power plant the sources of the airborne 131 I species were determined over a period of 5 months. During power operation the main source of the radiologically decisive elemental 131 I was the exhaust from the hoods in which samples from the primary coolant are taken and processed. During refueling outage elemental 131 I was mainly contributed by the containment purge air. By efficient filtration of these exhausts, a reduction of the ingestion dose, caused by the total 131 I stack release, by a factor of nearly 4 during power operation and of possibly 10 during refueling outage can be accomplished. (author)

  12. Challenges of adolescent and maturing nuclear plants: a chemistry perspective on maintenance and outages

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, J.G. [Bruce Power, Chemistry Design, Plant Design Engineering, Tiverton, Ontario (Canada)]. E-mail: john.roberts@brucepower.com

    2003-07-01

    In his address to the Canadian Nuclear Society, Bruce Power's Section Manager for Chemistry Design will relate how Designers and Specifiers for Plant and Components have historically limited their approach to that of new plants. As nuclear plants become operational, John G. Roberts will explain how the requirements to protect the assets change as a result of changed capabilities, environments and requirements. John will offer examples to show how challenges were met during construction and commissioning. While plant changes are often necessary following commissioning to prevent serious operational problems, John will also discuss ways in which planners, suppliers and maintenance staff can broaden their views and embrace new work methods to ensure those changes don't unwittingly create new challenges. (author)

  13. Challenges of adolescent and maturing nuclear plants: a chemistry perspective on maintenance and outages

    International Nuclear Information System (INIS)

    Roberts, J.G.

    2003-01-01

    In his address to the Canadian Nuclear Society, Bruce Power's Section Manager for Chemistry Design will relate how Designers and Specifiers for Plant and Components have historically limited their approach to that of new plants. As nuclear plants become operational, John G. Roberts will explain how the requirements to protect the assets change as a result of changed capabilities, environments and requirements. John will offer examples to show how challenges were met during construction and commissioning. While plant changes are often necessary following commissioning to prevent serious operational problems, John will also discuss ways in which planners, suppliers and maintenance staff can broaden their views and embrace new work methods to ensure those changes don't unwittingly create new challenges. (author)

  14. Regulatory control of maintenance activities in Argentine nuclear power plants

    International Nuclear Information System (INIS)

    Calvo, J.C.; Caruso, G.

    2000-01-01

    The main maintenance objective is to assure that the safety features of structures, components and systems of nuclear power plants are kept as designed. Therefore, there is a direct relationship between safety and maintenance. Owing to the above mentioned, maintenance activities are considered a relevant regulatory issue for the Argentine Nuclear Regulatory Authority (ARN). This paper describes the regulatory control to maintenance activities of Argentine nuclear power plants. It also addresses essential elements for maintenance control, routine inspections, special inspections during planned outages, audits and license conditions and requirements. (author)

  15. Risks of turbine generators at WWER-440 nuclear power plants

    International Nuclear Information System (INIS)

    Virolainen, T.; Marttila, J.; Aulamo, H.

    1998-01-01

    Many serious fires and incidents have occurred in the turbine halls of nuclear power plants, resulting in serious damage and long shutdown outages. Some of these incidents have endangered the safe shutdown of the plants because of the location of lack of vital fire protection safety systems. A detailed analysis is necessary for all those plants that have equipment important for safe shutdown located in the turbine hall or its vicinity without strict fire separation by fire rated barriers. A reduction in the fire frequencies of the turbine hall is an additional way of improving safety. This is possible by improving all aspects of turbine generator operation. (author)

  16. Operational experience with nuclear power plants - outage statistics, causes and effects

    International Nuclear Information System (INIS)

    Kutsch, W.

    1980-01-01

    Whether operating experience is good or bad is not a question of the subjective impression. Availability, reliability, environmental influence, safety and economy are of a significance which cannot be expressed by figures. To what extent the result may be called good or bad can be noticed by comparing the results with the projected expected values or by comparing them with other plants locally or overseas. (orig.)

  17. Exact closed form expressions for outage probability of GSC receivers over Rayleigh fading channel subject to self-interference

    KAUST Repository

    Nam, Sungsik; Hasna, Mazen Omar; Alouini, Mohamed-Slim

    2010-01-01

    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

  18. Palisades Nuclear Plant. Semiannual operating report, January--June 1975

    International Nuclear Information System (INIS)

    1975-01-01

    The first half of this period was a continuation of Outage 74-4. Retubing of the main condenser was completed and additional Eddy Current Testing in the steam generators was accomplished. On April 2, 1975 the unit returned to service to conduct the Steam Generator Flushing Program. From April 2 through June 20, 1975 the plant operated at power levels up to 90 percent, with two brief outage interruptions. On April 6, the turbine was tripped because of a leak in the flow instrument tap in the drain line from a feedwater heater to the moisture separator drain tank and on April 22, the turbine tripped due to low oil pressure in the electrohydraulic control system caused by a cracked fitting in the piping to a governor valve. In both instances, the plant was returned to service in a matter of a few hours. The plant was removed from service from June 20 until June 30, 1975 for control rod drive seal repair. The plant resumed operation on June 30, 1975. After a few hours' operation, an erratic feedwater control system tripped the unit from service; however, the unit returned to service the same day. An all volatile treatment program for secondary water has achieved reasonable water chemistry stability and continuous blowdown has removed small quantities of phosphate from the steam generators. Operation continued with two low pressure feedwater heaters and drain cooler bypassed in each train, pending retubing of the feedwater heaters. Two rows of blading of a low pressure turbine were replaced. (U.S.)

  19. Summary of operating experience in Swiss nuclear power plants 1993

    International Nuclear Information System (INIS)

    1994-07-01

    In 1993 the Swiss nuclear power plants produced their third highest combined annual output. The contribution to the total electricity generation in the country was close to 37%. Replacement of the steam generators in Beznau Unit 1 resulted in a longer than usual annual outage. For the other four units the availability figures were close to, or exceeded, those of previous years. The energy utilization was, however, lowered due to load reduction in autumn resulting from unusually high production by the hydro-electric power plants. The steam generator replacement at Beznau enabled an increase in electrical power of about 2% without increase in reactor power. With the approval of the Swiss government in December 1992, the output of the Muehleberg power plant was increased in two stages by a total of 10%. The application for an unlimited operating license for Beznau Unit 2, and for a power uprate at the Leibstadt power plant, are still pending. The average number of scrams at the Swiss plants remained stable, at less than one scram per reactor year. As a result of experience in the Swedish nuclear power plant at Barsebaeck, the suction strainers of the emergency core cooling systems of the boiling water reactors at Muehleberg and Leibstadt were replaced by strainers with larger surface areas. The re-inspection of crack indications previously detected in the core shroud of the Muehleberg reactor and the penetration tubes in the reactor pressure vessel closure head of Beznau revealed no growth during the intervening operating periods. Following the completion of installation activities during the annual outages at Beznau Unit 1, Goesgen and Leibstadt, all Swiss nuclear power plants are now equipped with filtered containment venting systems. (author) figs., tabs

  20. Trends of Nuclear Power Plant support engineering in the Early 21st century

    International Nuclear Information System (INIS)

    Cerezo, L. M.

    2001-01-01

    The rapid shift towards deregulation in the Electricity Industry in the 21st Century is placing a dramatic new emphasis on mid-term returns on generation investments. The economic pressures on capital-intensive generation systems such as hydraulic, coal and in particular nuclear are escalating significantly. In the old regulated system, the only concern was with marginal production costs, not total costs, as the return on the investment was ensured. Marginal production costs of Nuclear Power Plants are very low, which makes these plants ideal for base operation, but when the costs of recovering the investment are included, the total nuclear Kwh costs are relatively high. In addition, this industry is characterized by some specific economic risks resulting from the following: the risk of accidents, which, though not very probable, have a significant impact on the whole industry; the risk of prolonged, unscheduled outages involving prohibitively high costs, given the ratio of fixed/variable costs, the risk that outages are extended for refueling; and regulatory risks, which have major economic repercussions. (Author)