WorldWideScience

Sample records for critical gen-iv systems

  1. Fuel research for subcritical and critical GEN-IV systems cooled by heavy liquid metal

    International Nuclear Information System (INIS)

    Sobolev, V.; Verwerft, M.

    2009-01-01

    The participation of the Belgian Nuclear Research Centre SCK-CEN in the worldwide GEN-IV research can be considered as an opportunity. Today's GEN-IV research at SCK-CEN is mainly driven by the interests of the project MYRRHA (Multipurpose hYbrid Research Reactor for High-tech Applications). The main goal of this project is to build at SCK-CEN in Mol a new generation fast spectrum, subcritical, research and materials testing reactor MYRRHA driven by a high-energy proton accelerator. This GEN-IV MTR is cooled by heavy liquid metal (Pb-Bi) and will be used for the ADS concept demonstration, testing and qualification of new fuels, transmutation targets and innovative materials. On the European scale, MYRRHA is integrated in the Euratom FP6 Integrated Project (IP) EUROTRANS (EUROpean research programme for TRANSmutation of high level nuclear waste in an accelerator driven system), as the small-scale experimental machine for transmutation demonstration called XT-ADS. Last but not least, this experimental facility will also demonstrate the technological feasibility of the LFR (Lead-cooled Fast Reactor) GEN-IV concept; in EU the LFR design studies are performed in the framework of the Euratom FP6 ELSY (European Lead-cooled SYstem) project, where SCK-CEN is a partner. Among the research needed to ensure a safe and reliable operation of the MYRRHA/XT ADS reactor, the development and qualification of fuel and cladding materials have been recognized as one of the main key issues to be addressed

  2. JRC-IE's research of safety of Gen IV systems

    International Nuclear Information System (INIS)

    Tsige-Tamirat, H.; Ranguelova, V.; Feutterer, M.; Ammirabile, L.; Carlsson, J.; D'Agata, E.; Laurie, M.; Magallon, D.

    2010-01-01

    The Institute for Energy (IE), one of the seven scientific Institutes of the Joint Research Centre (JRC) of the European Commission, has the mission to provide scientific and technical support for the conception, development, implementation and monitoring of community policies related to energy. To accomplish its mission, IE performs research in the areas of renewable energies, safety and sustainability of nuclear energy for current and future reactor systems, energy technic/economic assessment, and security of energy supply. The Generation IV International Forum (GIF) is a cooperative international endeavour organized to carry out R and D needed to establish the feasibility and performance capabilities of the next generation nuclear energy systems and support the progress towards their realization. The EU, represented by EURATOM and with the JRC as implementing agent, is working together with other GIF partners to perform pre-competitive R and D on key technologies to be implemented in future nuclear systems. IE is engaged in experimental research, simulation and modeling, scientific, feasibility and engineering studies on innovative nuclear reactor systems needed to support the EURATOM contribution to GEN IV initiative, in particular in assessment of innovative fuels and materials, development of new reactor core concepts and safety solutions and knowledge management and preservation. IE's research activities on Generation IV reactor systems are focused on the assessment of the potential of such systems to meet long term EU energy needs with respect to economical advantages, enhanced safety, sustainability, and proliferation resistance. IE participates in international collaborations and has bilateral research cooperation both with European and non-European partners. This paper gives an overview of IE's current research activities on the Gen IV reactor systems related to safety. (authors)

  3. Study on high temperature design methodology of heat-resistant materials for GEN-IV systems

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Woo Seog; Kim, D. W.; Kim, S. H.; Kim, W. G.; Kim, J. H.; Park, D. G.; Yoon, J. H.; Lee, H. Y.; Hing, J. H

    2005-08-15

    Analysis of the existing high temperature design and assessment codes such as US(ASME-NH,Draft Code Case for Alloy 617), France(RCC-MR), UK(R5), Japan(BDS/DDS/FDS) for Gen IV reactor structure has been carried out. In addition the scope and fields for research and development is needed in the future have been defined. For assessing the high temperature creep cracks, time dependent fracture mechanics (TDFM) parameters of the C and Ct were analyzed. The creep propagation data were obtained from the creep crack growth tests for type 316LN stainless steels, and creep crack growth testing machine for Gen-IV system up to 950 .deg. C was set up. Damage mechanism and causes for creep-fatigue were investigated. The difference between prediction creep-fatigue life and experimental life were investigated. Material properties for analysis creep-fatigue damage were recommended. The assessment procedure (Draft) on creep-fatigue crack initiation has been developed based on the technical appendix A16 of French RCC-MR code. Ultrasonic wave signal against creep ruptured specimens of type 316LN stainless steel was obtained. It was identified that creep damage can be evaluated by ultrasonic method. The NDT techniques evaluated include Barkhausen noise, magnetic hysteresis parameters, positron annihilation, X-ray diffraction and small angle neutron scattering. Experimental procedure and evaluation method of material integrity were developed through the fracture toughness test of Cr-Mo steel.

  4. Overall system description and safety characteristics of Prototype Gen IV Sodium Cooled Fast Reactor in Korea

    International Nuclear Information System (INIS)

    Yoo, Jae Woon; Chang, Jin Wook; Lim, Jae Yong; Cheon, Jin Sik; Lee, Tae Ho; Kim, Sung Kyun; Lee, Kwi Lim; Joo, Hyung Kook

    2016-01-01

    The Prototype Gen IV sodium cooled fast reactor (PGSFR) has been developed for the last 4 years, fulfilling the technology demonstration of the burning capability of transuranic elements included in light water reactor spent nuclear fuel. The PGSFR design has been focused on the robustness of safety systems by enhancing inherent safety characteristics of metal fuel and strengthening passive safety features using natural circulation and thermal expansion. The preliminary safety information document as a major outcome of the first design phase of PGSFR development was issued at the end of 2015. The project entered the second design phase at the beginning of 2016. This paper summarizes the overall structures, systems, and components of nuclear steam supply system and safety characteristics of the PGSFR. The research and development activities to demonstrate the safety performance are also briefly introduced in the paper

  5. Overall System Description and Safety Characteristics of Prototype Gen IV Sodium Cooled Fast Reactor in Korea

    Directory of Open Access Journals (Sweden)

    Jaewoon Yoo

    2016-10-01

    Full Text Available The Prototype Gen IV sodium cooled fast reactor (PGSFR has been developed for the last 4 years, fulfilling the technology demonstration of the burning capability of transuranic elements included in light water reactor spent nuclear fuel. The PGSFR design has been focused on the robustness of safety systems by enhancing inherent safety characteristics of metal fuel and strengthening passive safety features using natural circulation and thermal expansion. The preliminary safety information document as a major outcome of the first design phase of PGSFR development was issued at the end of 2015. The project entered the second design phase at the beginning of 2016. This paper summarizes the overall structures, systems, and components of nuclear steam supply system and safety characteristics of the PGSFR. The research and development activities to demonstrate the safety performance are also briefly introduced in the paper.

  6. The Atalante facility at CEA/Marcoule: towards Gen IV systems fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Bordier, Gilles; Warin, Dominique; Masson, Michel [CEA/Marcoule Direction, BP 17171 - 30207 - Bagnols-sur-Ceze Cedex (France)

    2008-07-01

    The Atalante facility is a complete set of 18 hot labs and 9 shielded cells devoted to the research and development on fuel cycle. The activities correspond to 4 major sectors of nuclear research: -) to support the operation of actual reprocessing plants with the aim of adapting the head of the process to the increase of the spend fuel burn-up and to different types of new burnt fuels to be reprocessed (including MOX, USi or UMo fuels); -) to develop the COEX{sup TM} process that jointly manages uranium and plutonium from the dissolution of spent fuel to the production of UPuO{sub 2} powder and the fabrication of MOX fuel pellets; -) to prepare the recycling of minor actinides (MA) by partitioning or by grouped actinide extraction, and by MA bearing fuel fabrication; -) to study the long term behavior of high level waste conditioning matrices and especially self irradiation and leaching of vitrified waste. The first hot lab of Atalante was operated in 1992, the process shielded cell (CBP) in 2003 and the last LN1 lab in 2005, while at the same time a large scale demonstration test on the DIAMEX-SANEX MA partitioning process was performed. Now some new challenges involve further necessary evolutions of the facility. Some are related to safety assessment and operating flexibility; the major evolutions will come from new scientific goals and research programs. Furthermore, minor actinides materials irradiation tests in fast reactors will be prepared in the framework of a large international cooperation (GACID program) and need the production of significant amounts of MA bearing mixed U-Pu oxide compounds in new hot labs and shielded cells equipment. The major new research tools are presented and we highlight how Atalante is a unique facility which brings a real opportunity to reinforce the European and international scientific cooperation in order to prepare the next Gen IV fuel cycle. (authors)

  7. The Atalante facility at CEA/Marcoule: towards Gen IV systems fuel cycle

    International Nuclear Information System (INIS)

    Bordier, Gilles; Warin, Dominique; Masson, Michel

    2008-01-01

    The Atalante facility is a complete set of 18 hot labs and 9 shielded cells devoted to the research and development on fuel cycle. The activities correspond to 4 major sectors of nuclear research: -) to support the operation of actual reprocessing plants with the aim of adapting the head of the process to the increase of the spend fuel burn-up and to different types of new burnt fuels to be reprocessed (including MOX, USi or UMo fuels); -) to develop the COEX TM process that jointly manages uranium and plutonium from the dissolution of spent fuel to the production of UPuO 2 powder and the fabrication of MOX fuel pellets; -) to prepare the recycling of minor actinides (MA) by partitioning or by grouped actinide extraction, and by MA bearing fuel fabrication; -) to study the long term behavior of high level waste conditioning matrices and especially self irradiation and leaching of vitrified waste. The first hot lab of Atalante was operated in 1992, the process shielded cell (CBP) in 2003 and the last LN1 lab in 2005, while at the same time a large scale demonstration test on the DIAMEX-SANEX MA partitioning process was performed. Now some new challenges involve further necessary evolutions of the facility. Some are related to safety assessment and operating flexibility; the major evolutions will come from new scientific goals and research programs. Furthermore, minor actinides materials irradiation tests in fast reactors will be prepared in the framework of a large international cooperation (GACID program) and need the production of significant amounts of MA bearing mixed U-Pu oxide compounds in new hot labs and shielded cells equipment. The major new research tools are presented and we highlight how Atalante is a unique facility which brings a real opportunity to reinforce the European and international scientific cooperation in order to prepare the next Gen IV fuel cycle. (authors)

  8. Conversion of actinide solutions for the production of MA bearing fuels for Gen IV fast reactor systems

    International Nuclear Information System (INIS)

    Fernandez, A.; McGinley, J.; Somers, J.

    2008-01-01

    The conversion of the solution to solid for fuels containing minor actinides for accelerator driven systems or Gen IV fast reactors cannot be made by conventional ammonia or oxalate precipitation as is the case in today's reprocessing plant. The small particle size and concomitant dust that is produced in subsequent processing steps will not permit use of these processes on industrial scale. Innovation is needed to avoid dust generating powders, and indeed to simplify the processes themselves. Two such processing routes have been developed at the JRC-ITU. The sol gel route has been used to produce fuel containing Am and Np for the SUPERFACT, TRABANT and other irradiation experiments. The infiltration process has also been established and fuels have been produced for the FUTURIX and HELIOS experiments. (authors)

  9. Conversion of actinide solutions for the production of MA bearing fuels for Gen IV fast reactor systems

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.; McGinley, J.; Somers, J. [European Commission, Joint Research Centre, Institute for Transuranium Elements P.O.Box 2340, Karlsruhe, D-76125 (Germany)

    2008-07-01

    The conversion of the solution to solid for fuels containing minor actinides for accelerator driven systems or Gen IV fast reactors cannot be made by conventional ammonia or oxalate precipitation as is the case in today's reprocessing plant. The small particle size and concomitant dust that is produced in subsequent processing steps will not permit use of these processes on industrial scale. Innovation is needed to avoid dust generating powders, and indeed to simplify the processes themselves. Two such processing routes have been developed at the JRC-ITU. The sol gel route has been used to produce fuel containing Am and Np for the SUPERFACT, TRABANT and other irradiation experiments. The infiltration process has also been established and fuels have been produced for the FUTURIX and HELIOS experiments. (authors)

  10. Progress in the development of the neutron flux monitoring system of the French GEN-IV SFR: simulations and experimental validations [ANIMMA--2015-IO-98

    Energy Technology Data Exchange (ETDEWEB)

    Jammes, C.; Filliatre, P.; De Izarra, G. [CEA, DEN, DER, Instrumentation, Sensors and Dosimetry Laboratory, Cadarache, F-13108 Saint-Paul-lez-Durance, (France); Elter, Zs.; Pazsit, I. [Chalmers University of Technology, Department of Applied Physics, Division of Nuclear Engineering, SE-412 96 Goteborg, (Sweden); Verma, V.; Hellesen, C.; Jacobsson, S. [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala, (Sweden); Hamrita, H.; Bakkali, M. [CEA, DRT, LIST, Sensors and Electronic Architecture Laboratory, Saclay, F-91191 Gif Sur Yvette, (France); Chapoutier, N.; Scholer, A-C.; Verrier, D. [AREVA NP, 10 rue Juliette Recamier F-69456 Lyon, (France); Cantonnet, B.; Nappe, J-C. [PHONIS France S.A.S, Nuclear Instrumentation, Avenue Roger Roncier, B.P. 520, F-19106 Brive Cedex, (France); Molinie, P.; Dessante, P.; Hanna, R.; Kirkpatrick, M.; Odic, E. [Supelec, Department of Power and Energy System, F-91192 Gif Sur Yvette, (France); Jadot, F. [CEA, DEN, DER, ASTRID Project Group, Cadarache, F-13108 Saint-Paul-lez-Durance, (France)

    2015-07-01

    The neutron flux monitoring system of the French GEN-IV sodium-cooled fast reactor will rely on high temperature fission chambers installed in the reactor vessel and capable of operating over a wide-range neutron flux. The definition of such a system is presented and the technological solutions are justified with the use of simulation and experimental results. (authors)

  11. A Review of Alloy 800H for Applications in the Gen IV Nuclear Energy Systems

    International Nuclear Information System (INIS)

    Ren, Weiju; Swindeman, Robert W.

    2010-01-01

    Alloy 800H is currently under consideration for applications in the Next Generation Nuclear Plant at operational temperatures above 750 C. To provide supporting information in this paper at the attempt to facilitate the consideration, service requirements of the nuclear system for structural materials is first described; and then an extensive review of Alloy 800H is given on its codification with respect to development and research history, mechanical behavior and design allowables, metallurgical aging resistance, environmental effect considerations, data requirements and availability, weldments, as well as many other aspects relevant to the intended nuclear application; an finally further research and development activities to support the materials qualification are suggested.

  12. ASN’s actions in GEN IV reactors and Sodium Fast Reactors (SFR)

    International Nuclear Information System (INIS)

    Belot, Clotilde

    2013-01-01

    The ASN is involved in 3 actions concerning GEN IV: • Overview of nuclear reactor GEN IV systems; • Specific analysis about transmutation; • Prototype reactor ASTRID (SFR). Furthermore theses actions are in the beginning (no conclusions or results available)

  13. Gen IV Materials Handbook Implementation Plan

    International Nuclear Information System (INIS)

    Rittenhouse, P.; Ren, W.

    2005-01-01

    A Gen IV Materials Handbook is being developed to provide an authoritative single source of highly qualified structural materials information and materials properties data for use in design and analyses of all Generation IV Reactor Systems. The Handbook will be responsive to the needs expressed by all of the principal government, national laboratory, and private company stakeholders of Gen IV Reactor Systems. The Gen IV Materials Handbook Implementation Plan provided here addresses the purpose, rationale, attributes, and benefits of the Handbook and will detail its content, format, quality assurance, applicability, and access. Structural materials, both metallic and ceramic, for all Gen IV reactor types currently supported by the Department of Energy (DOE) will be included in the Gen IV Materials Handbook. However, initial emphasis will be on materials for the Very High Temperature Reactor (VHTR). Descriptive information (e.g., chemical composition and applicable technical specifications and codes) will be provided for each material along with an extensive presentation of mechanical and physical property data including consideration of temperature, irradiation, environment, etc. effects on properties. Access to the Gen IV Materials Handbook will be internet-based with appropriate levels of control. Information and data in the Handbook will be configured to allow search by material classes, specific materials, specific information or property class, specific property, data parameters, and individual data points identified with materials parameters, test conditions, and data source. Details on all of these as well as proposed applicability and consideration of data quality classes are provided in the Implementation Plan. Website development for the Handbook is divided into six phases including (1) detailed product analysis and specification, (2) simulation and design, (3) implementation and testing, (4) product release, (5) project/product evaluation, and (6) product

  14. Improvement of Steam Generator Reliability for GEN-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong O; Kim Se Yun; Kim, Seok Hoon; Eoh, Jae Hyuk; Lee, Hyeong Yeon; Choi, Byung Seon

    2005-11-15

    The R and D items performed in this study were selected from the R and D task of ' Reliability improvement of Steam Generator' of GEN-IV SFR Component Design and BOP. Since this project deals with one of the most important issues for a GEN-IV SFR system, it needs to enhance the domestic technical backgrounds associated with the corresponding R and D items even for a very short period by 2005. This study provides the R and D results for i) Development of assessment methodology for dissimilar metal weld and ii) Development of multi-dimensional simulation methodology for a SWR event in a SFR steam generator.

  15. Improvement of Steam Generator Reliability for GEN-IV SFR

    International Nuclear Information System (INIS)

    Kim, Seong O; Kim Se Yun; Kim, Seok Hoon; Eoh, Jae Hyuk; Lee, Hyeong Yeon; Choi, Byung Seon

    2005-11-01

    The R and D items performed in this study were selected from the R and D task of ' Reliability improvement of Steam Generator' of GEN-IV SFR Component Design and BOP. Since this project deals with one of the most important issues for a GEN-IV SFR system, it needs to enhance the domestic technical backgrounds associated with the corresponding R and D items even for a very short period by 2005. This study provides the R and D results for i) Development of assessment methodology for dissimilar metal weld and ii) Development of multi-dimensional simulation methodology for a SWR event in a SFR steam generator

  16. Safety Design Criteria (SDC) for Gen-IV Sodium-cooled Fast Reactor

    International Nuclear Information System (INIS)

    Nakai, Ryodai

    2013-01-01

    SDC Development Background & Objectives: • Safety Design Criteria (SDC) Development for Gen-IV SFR: – Proposed at the GIF Policy Group (PG) meeting in October 2010 –SDC “harmonization” is increasingly important for: • Realization of enhanced safety designs meeting to Gen-IV safety goals and safety approach common to SFR systems; • Preparation for the forthcoming licensing in the near future; • Because Gen-IV SFR are progressing into conceptual design stage. • The SDC is the Reference criteria: – Of the designs of safety-related Structures, Systems & Components that are specific to the SFR system; – For clarifying the requisites systematically & comprehensively; – When the technology developers apply the basic safety approach and use the codes & standards for conceptual design of the Gen-IV SFR system

  17. Progress in the development of the neutron flux monitoring system of the French GEN-IV SFR: simulations and experimental validations [ANIMMA--2015-IO-392

    Energy Technology Data Exchange (ETDEWEB)

    Jammes, C.; Filliatre, P.; Izarra, G. de [CEA, DEN, Cadarache, Reactor Studies Department, 13108 Saint-Paul-lez-Durance (France); Elter, Zs. [CEA, DEN, Cadarache, Reactor Studies Department, 13108 Saint-Paul-lez-Durance (France); Chalmers University of Technology, Department of Applied Physics, Division of Nuclear Engineering, SE-412 96 Goeteborg (Sweden); Verma, V. [CEA, DEN, Cadarache, Reactor Studies Department, 13108 Saint-Paul-lez-Durance (France); Uppsala University, Division of Applied Nuclear Physics, Box 516, SE-75120 Uppsala (Sweden); Hamrita, H.; Bakkali, M. [CEA, DRT, LIST, Metrology, Instrumentation and Information Department, Saclay, 91191 Gif-sur-Yvette (France); Chapoutier, N.; Scholer, A.C.; Verrier, D. [AREVA NP, 10 rue Juliette Recamier F-69456 Lyon (France); Hellesen, C.; Jacobsson, S. [Uppsala University, Division of Applied Nuclear Physics, Box 516, SE-75120 Uppsala (Sweden); Pazsit, I. [Chalmers University of Technology, Department of Applied Physics, Division of Nuclear Engineering, SE-412 96 Goeteborg (Sweden); Cantonnet, B.; Nappe, J.C. [PHOTONIS France, Nuclear Instrumentation, 19100 Brive-la-Gaillarde (France); Molinie, P.; Dessante, P.; Hanna, R.; Kirkpatrick, M.; Odic, E. [Supelec, Energy Department, 3 rue Joliot-Curie, 91191 Gif-sur-Yvette (France)

    2015-07-01

    France has a long experience of about 50 years in designing, building and operating sodium-cooled fast reactors (SFR) such as RAPSODIE, PHENIX and SUPER PHENIX. Fast reactors feature the double capability of reducing nuclear waste and saving nuclear energy resources by burning actinides. Since this reactor type is one of those selected by the Generation IV International Forum, the French government asked, in the year 2006, CEA, namely the French Alternative Energies and Atomic Energy Commission, to lead the development of an innovative GEN-IV nuclear- fission power demonstrator. The major objective is to improve the safety and availability of an SFR. The neutron flux monitoring (NFM) system of any reactor must, in any situation, permit both reactivity control and power level monitoring from startup to full power. It also has to monitor possible changes in neutron flux distribution within the core region in order to prevent any local melting accident. The neutron detectors will have to be installed inside the reactor vessel because locations outside the vessel will suffer from severe disadvantages; radially the neutron shield that is also contained in the reactor vessel will cause unacceptable losses in neutron flux; below the core the presence of a core-catcher prevents from inserting neutron guides; and above the core the distance is too large to obtain decent neutron signals outside the vessel. Another important point is to limit the number of detectors placed in the vessel in order to alleviate their installation into the vessel. In this paper, we show that the architecture of the NFM system will rely on high-temperature fission chambers (HTFC) featuring wide-range flux monitoring capability. The definition of such a system is presented and the justifications of technological options are brought with the use of simulation and experimental results. Firstly, neutron-transport calculations allow us to propose two in-vessel regions, namely the above-core and under

  18. Gen IV Materials Handbook Functionalities and Operation

    International Nuclear Information System (INIS)

    Ren, Weiju

    2009-01-01

    This document is prepared for navigation and operation of the Gen IV Materials Handbook, with architecture description and new user access initiation instructions. Development rationale and history of the Handbook is summarized. The major development aspects, architecture, and design principles of the Handbook are briefly introduced to provide an overview of its past evolution and future prospects. Detailed instructions are given with examples for navigating the constructed Handbook components and using the main functionalities. Procedures are provided in a step-by-step fashion for Data Upload Managers to upload reports and data files, as well as for new users to initiate Handbook access.

  19. Gen IV. Technical and economical aspects

    International Nuclear Information System (INIS)

    Kaluzny, Y.; Legee, F.

    2010-01-01

    In this presentation author deals with development of nuclear reactor type of Generation IV. He concluded that: - Nuclear energy is competitive with regards to the other generation sources; Its competitiveness also increases with CO 2 cost. Considering the nuclear cost breakdown of LWR reactors, it turns out that the uranium is currently not in the range of a threshold for FBR deployment; - The global balance of uranium supply and demand and also innovation required to fulfil GEN IV objectives would probably imply the emergence of fast reactor competitiveness after the turn of the mid-century; - We shall need fast reactors in the coming decade.

  20. Gen IV Materials Handbook Functionalities and Operation

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL

    2009-12-01

    This document is prepared for navigation and operation of the Gen IV Materials Handbook, with architecture description and new user access initiation instructions. Development rationale and history of the Handbook is summarized. The major development aspects, architecture, and design principles of the Handbook are briefly introduced to provide an overview of its past evolution and future prospects. Detailed instructions are given with examples for navigating the constructed Handbook components and using the main functionalities. Procedures are provided in a step-by-step fashion for Data Upload Managers to upload reports and data files, as well as for new users to initiate Handbook access.

  1. Structural materials for Gen-IV nuclear reactors: Challenges and opportunities

    Science.gov (United States)

    Murty, K. L.; Charit, I.

    2008-12-01

    Generation-IV reactor design concepts envisioned thus far cater toward a common goal of providing safer, longer lasting, proliferation-resistant and economically viable nuclear power plants. The foremost consideration in the successful development and deployment of Gen-IV reactor systems is the performance and reliability issues involving structural materials for both in-core and out-of-core applications. The structural materials need to endure much higher temperatures, higher neutron doses and extremely corrosive environment, which are beyond the experience of the current nuclear power plants. Materials under active consideration for use in different reactor components include various ferritic/martensitic steels, austenitic stainless steels, nickel-base superalloys, ceramics, composites, etc. This paper presents a summary of various Gen-IV reactor concepts, with emphasis on the structural materials issues depending on the specific application areas. This paper also discusses the challenges involved in using the existing materials under both service and off-normal conditions. Tasks become increasingly complex due to the operation of various fundamental phenomena like radiation-induced segregation, radiation-enhanced diffusion, precipitation, interactions between impurity elements and radiation-produced defects, swelling, helium generation and so forth. Further, high temperature capability (e.g. creep properties) of these materials is a critical, performance-limiting factor. It is demonstrated that novel alloy and microstructural design approaches coupled with new materials processing and fabrication techniques may mitigate the challenges, and the optimum system performance may be achieved under much demanding conditions.

  2. Safeguards Licensing Aspects of a Future Gen IV Test Facility - a Case Study

    International Nuclear Information System (INIS)

    Lindell, M. Aberg; Grape, S.; Hakansson, A.; Svaerd, S. Jacobsson

    2010-01-01

    The scope of this study covers safeguards licensing aspects of a possible future Gen IV demonstration facility. As a basis for the investigation, the facility was assumed to be located in Sweden, comprising a lead-cooled fast reactor and a reprocessing plant with fuel fabrication. The aim has been to identify safeguards requirements that may be set by the IAEA and the Swedish Radiation Safety Authority, and also to suggest how the safeguards system could be implemented in practice. The changed usage and handling of nuclear fuel, as compared to that of today, has been examined in order to determine how today's safeguards measures can be modified and extended to meet the needs of the demonstration facility. This work is part of GENIUS, the Swedish Gen IV research and development programme, which emphasizes lead-cooled fast reactors. (author)

  3. GEN IV reactors: Where we are, where we should go

    International Nuclear Information System (INIS)

    Locatelli, G.; Mancini, M.; Todeschini, N.

    2012-01-01

    GEN IV power plants represent the mid-long term option of the nuclear sector. International literature proposes many papers and reports dealing with these reactors, but there is an evident difference of type and shape of information making impossible each kind of detailed comparison. Moreover, authors are often strongly involved in some particular design; this creates many difficulties in their super-partes position. Therefore it is necessary to put order in the most relevant information to understand strengths and weaknesses of each design and derive an overview useful for technicians and policy makers. This paper presents the state-of the art for GEN IV nuclear reactors providing a comprehensive literature review of the different designs with a relate taxonomy. It presents the more relevant references, data, advantages, disadvantages and barriers to the adoptions. In order to promote an efficient and wide adoption of GEN IV reactors the paper provides the pre-conditions that must be accomplished, enabling factors promoting the implementation and barriers limiting the extent and intensity of its implementation. It concludes outlying the state of the art of the most important R and D areas and the future achievements that must be accomplished for a wide adoption of these technologies. (authors)

  4. Reactor physics challenges in GEN-IV reactor design

    International Nuclear Information System (INIS)

    Driscoll, Michael K.; Hejzlar, Pavel

    2005-01-01

    An overview of the reactor physics aspects of GENeration Four (GEN-IV) advanced reactors is presented, emphasizing how their special requirements for enhanced sustainability, safety and economics motivates consideration of features not thoroughly analyzed in the past. The resulting concept-specific requirements for better data and methods are surveyed, and some approaches and initiatives are suggested to meet the challenges faced by the international reactor physics community. No unresolvable impediments to successful development of any of the six major types of proposed reactors are identified, given appropriate and timely devotion of resources

  5. Reactor physics challenges in GEN-IV reactor design

    Energy Technology Data Exchange (ETDEWEB)

    Driscoll, Michael K.; Hejzlar, Pavel [Massachusetts Institute of Technology, MA (United States)

    2005-02-15

    An overview of the reactor physics aspects of GENeration Four (GEN-IV) advanced reactors is presented, emphasizing how their special requirements for enhanced sustainability, safety and economics motivates consideration of features not thoroughly analyzed in the past. The resulting concept-specific requirements for better data and methods are surveyed, and some approaches and initiatives are suggested to meet the challenges faced by the international reactor physics community. No unresolvable impediments to successful development of any of the six major types of proposed reactors are identified, given appropriate and timely devotion of resources.

  6. Market share scenarios for Gen-DIII and gen-IV reactors in Europe

    International Nuclear Information System (INIS)

    Roelofs, F.; Heek, A. V.; Durpel, L. V. D.

    2008-01-01

    Nuclear energy is back on the agenda worldwide in order to meet growing energy demand and especially the growth in electricity demand. Many objectives direct to an increased use of nuclear energy, i.e. minimising energy costs, reducing climate change effects and others. In the light of the potential renewed growth of nuclear energy, the public demands a clear view on what nuclear energy may contribute towards meeting these objectives and especially how nuclear energy may address some socio-political obstructions with respect to economics, radioactive waste, safety and proliferation of fissile materials. To address these questions, the future nuclear reactor park mix in Europe has been analysed applying an integrated dynamic process modelling technique. Various market share scenarios for nuclear energy are derived including sub-variants with regard to the intra-nuclear options. In the analyses, it is assumed that different types of new reactors may be built, taking into account the introduction date of considered Gen-Ill (i.e. EPR) and Gen-IV (i.e. SCWR, HTR, FR) reactors, and the economic evaluation of the complete fuel cycle. The assessment was undertaken using the DANESS code (Dynamic Analysis of Nuclear Energy System Strategies). The analyses show that given the considered realistic nuclear energy demand and given a limited number of available Gen-III and Gen-IV reactor types, the future European nuclear park will exist of combinations of Gen-III and Gen-IV reactors. This mix will always consist of a set of reactor types each having its specific strengths. The analyses also highlight the triggers influencing the choice between different nuclear energy deployment scenarios. (authors)

  7. Developing new nuclear curricula for GEN IV needs

    International Nuclear Information System (INIS)

    Ghitescu, P.; Pavel, G.L.

    2014-01-01

    States who wish to start and develop a nuclear program must take into consideration a strong proven strategy for developing a sustainable program. A complete nuclear research program must include: a good national strategy and support on the topic; strong research laboratories supported by good personnel; education component to provide sustainable and qualified workforce; national/international interest from stakeholders and governments and a well informed society. New demonstrators are foreseen for the next period to be built in Europe and skilled supporting personnel is strongly needed. Current situation in nuclear higher education with perspective will be analysed. EURATOM strongly supports development of multidisciplinary co-operational projects in order to built such novel initiatives. An example of such program supported by European Commission, ARCADIA, will be given. The project is based on the cooperation of a large number of participants all over Europe and the main purpose is to develop a road-map for Gen IV reactor. (authors)

  8. The status of proliferation resistance evaluation methodology development in GEN IV international forum

    International Nuclear Information System (INIS)

    Inoue, Naoko; Kawakubo, Yoko; Seya, Michio; Suzuki, Mitsutoshi; Kuno, Yusuke; Senzaki, Masao

    2010-01-01

    The Generation IV Nuclear Energy Systems International Forum (GIF) Proliferation Resistance and Physical Protection Working Group (PR and PP WG) was established in December 2002 in order to develop the PR and PP evaluation methodology for GEN IV nuclear energy systems. The methodology has been studied and established by international consensus. The PR and PP WG activities include development of the measures and metrics; establishment of the framework of PR and PP evaluation, the demonstration study using Example Sodium Fast Reactor (ESFR), which included the development of three evaluation approaches; the Case Study using ESFR and four kinds of threat scenarios; the joint study with GIF System Steering Committees (SSCs) of the six reactor design concepts; and the harmonization study with the IAEA's International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO). This paper reviews the status of GIF PR and PP studies and identifies the challenges and directions for applying the methodology to evaluate future nuclear energy systems in Japan. (author)

  9. Decay Heat Removal in GEN IV Gas-Cooled Fast Reactors

    International Nuclear Information System (INIS)

    Lap-Yan, C.; Wie, T. Y. C.

    2009-01-01

    The safety goal of the current designs of advanced high-temperature thermal gas-cooled reactors (HTRs) is that no core meltdown would occur in a depressurization event with a combination of concurrent safety system failures. This study focused on the analysis of passive decay heat removal (DHR) in a GEN IV direct-cycle gas-cooled fast reactor (GFR) which is based on the technology developments of the HTRs. Given the different criteria and design characteristics of the GFR, an approach different from that taken for the HTRs for passive DHR would have to be explored. Different design options based on maintaining core flow were evaluated by performing transient analysis of a depressurization accident using the system code RELAP5-3D. The study also reviewed the conceptual design of autonomous systems for shutdown decay heat removal and recommends that future work in this area should be focused on the potential for Brayton cycle DHRs.

  10. Environmental sensitivity studies for Gen-IV roadmap DUPIC scenario

    International Nuclear Information System (INIS)

    Jeong, Chang Joon

    2004-03-01

    The environmental effect of the DUPIC (Direct Use of Spent PWR Fuel in CANDU Reactors) fuel cycle, which is considered as one of the partial recycle scenario in Gen-IV roadmap, has been analyzed by using the dynamic analysis method. Through the parametric calculations for the DUPIC fuel cycle deployment time and the fraction of the DUPIC reactors, the environmental effects of the fuel cycle for important parameters such as the amount of spent fuel and the combined amounts of plutonium and minor actinides were estimated and compared to those of the once-through LWR fuel cycle. The results of the sensitivity calculations showed that an early deployment of the DUPIC fuel cycle with a high DUPIC reactor fraction can reduce the accumulation of spent fuel by up to 40%. More important is the associated reduction in the combined amount of plutonium and minor actinides, which may reduce the key repository parameter (long term decay heat). Therefore it is expected that favorable environmental effects will be the outcome of the implementation of the DUPIC fuel cycle

  11. A preliminary safety analysis for the prototype Gen IV Sodium-Cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwi Lim; Ha, Kwi Seok; Jeong, Jae Ho; Choi, Chi Woong; Jeong, Tae Kyeong; Ahn, Sang June; Lee, Seung Won; Chang, Won Pyo; Kang, Seok Hun; Yoo, Jae Woon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Korea Atomic Energy Research Institute has been developing a pool-type sodium-cooled fast reactor of the Prototype Gen-IV Sodium-cooled Fast Reactor (PGSFR). To assess the effectiveness of the inherent safety features of the PGSFR, the system transients during design basis accidents and design extended conditions are analyzed with MARS-LMR and the subchannel blockage events are analyzed with MATRA-LMR-FB. In addition, the in-vessel source term is calculated based on the super-safe, small, and simple reactor methodology. The results show that the PGSFR meets safety acceptance criteria with a sufficient margin during the events and keeps accidents from deteriorating into more severe accidents.

  12. A Virtual Reality Framework to Optimize Design, Operation and Refueling of GEN-IV Reactors

    International Nuclear Information System (INIS)

    Rizwan-uddin; Nick Karancevic; Stefano Markidis; Joel Dixon; Cheng Luo; Jared Reynolds

    2008-01-01

    Many GEN-IV candidate designs are currently under investigation. Technical issues related to material, safety and economics are being addressed at research laboratories, industry and in academia. After safety, economic feasibility is likely to be the most important criterion in the success of GEN-IV design(s). Lessons learned from the designers and operators of GEN-II (and GEN-III) reactors must play a vital role in achieving both safety and economic feasibility goals

  13. A Virtual Reality Framework to Optimize Design, Operation and Refueling of GEN-IV Reactors.

    Energy Technology Data Exchange (ETDEWEB)

    Rizwan-uddin; Nick Karancevic; Stefano Markidis; Joel Dixon; Cheng Luo; Jared Reynolds

    2008-04-23

    many GEN-IV candidate designs are currently under investigation. Technical issues related to material, safety and economics are being addressed at research laboratories, industry and in academia. After safety, economic feasibility is likely to be the most important crterion in the success of GEN-IV design(s). Lessons learned from the designers and operators of GEN-II (and GEN-III) reactors must play a vital role in achieving both safety and economic feasibility goals.

  14. The safety R and D for GEN-IV reactors in the European nuclear energy technology platform strategic research agenda

    International Nuclear Information System (INIS)

    Bruna, G.

    2009-01-01

    In the fall 2007 EC launched the Sustainable Nuclear Energy Technology Platform (SNE-TP). The SNE-TP governing board set-up three working groups (WG): 1) Strategic Research Agenda (SRA) WG, in charge of drafting road-maps to support research, development and demonstration for current and future NPPs; 2) Deployment Strategy (DS) WG, in charge of defining the research road-map implementation and 3) Education, Training and Knowledge management (ETKM) WG, which was aimed at issuing proposal to reinforce European education and attract young in the nuclear field. The SRA WG was mandated to prepare the SRA vision document based on the preliminary road-map sketched in the document published by the Commission earlier in 2007. The SRA WG was originally organized in 5 sub-groups covering specific topics (1) GEN II and III, III+, including Advanced LWR, 2) Advanced Fuel Cycle for waste minimization and resource optimization; 3) GEN IV Fast Systems (SFR, LFR, GFR, ADS); 4) GEN IV (V) HTR and non-electricity-production applications; 5) New Nuclear Large Research Infrastructures) and 5 other sub-groups dealing with more generic cross-cutting research activities applicable to many specific topics, namely: 1) Structural material research; 2) modeling, simulation and methods, including physical data and tools and means for qualification and validation; 3) Reactor Safety, including severe accidents and human factor; 4) Advanced Driver and Minor Actinide Fuels: science and properties; 5) Pre-normative Research, Codes and Standards.The present paper is mainly aimed at summarizing the content of the SRA Safety sub-chapter focusing on GEN-IV aspects

  15. European project SARGEN IV: safety approach and assessment of GEN IV reactors

    International Nuclear Information System (INIS)

    Ammirabile, L.

    2013-01-01

    • SARGEN I V has elaborated a proposal for the harmonization of safety assessment practices for GEN IV NPP. • An overall reinforcement of DiD is expected for GEN I V NPP, including improved independence between all levels of DiD. • An inherent approach should reinforce the fulfillment of fundamental safety functions e.g. the consequences for some situations should be reduced and the grace periods should be extended. For the same reason, the use of passive systems can be envisaged. • The need of complementary and integrated deterministic and probabilistic approaches is reiterated. • Methodologies: Some of them are not yet applied. • Assessment of hazards would be a challenging aspect of next generation of NPP safety assessment and should be improved, which is confirmed by the first insights of Fukushima Daiichi TEPCO reactors accidents. • Provisions to cope with extreme events notably to improve the grace period before cliff-edge effects and thus allowing back-up measures to be implemented have to be defined and should be considered as hardened equipments

  16. Overview of nuclear safety activities performed by JRC-IE on Gen IV fast reactor concepts

    Energy Technology Data Exchange (ETDEWEB)

    Tsige-Tamirat, H.; Ammirabile, L.; D' Agata, E.; Fuetterer, M.; Ranguelova, V. [European Commission, Joint Research Centre, Institute for Energy, Westerduinweg 3, 1755LE Petten (Netherlands)

    2010-07-01

    The European Strategic Energy Technology (SET) Plan recognizes the need to develop new energy technologies, in order to reduce greenhouse gas emissions and secure energy supply in Europe. Besides renewable energy and improved energy efficiency, a new generation of nuclear power plants and innovative nuclear power applications can play a significant role to achieve this goal. The JRC Institute for Energy 'Safety of Future Nuclear Reactors' (SFNR) Unit is engaged in experimental research, numerical simulation and modelling, scientific, feasibility and engineering studies on innovative nuclear reactor systems. This also represents a significant EURATOM contribution to the Generation IV International Forum. Its activities deal with, among others, the performance assessment of innovative fuels and materials, development of new reactor core concepts and safety solutions, and knowledge management and preservation. Special attention is given to fast reactor concepts, namely the sodium (SFR) and lead (LFR) cooled reactors. Recognizing the maturity of the SFR technology, the European Sustainable Nuclear Energy Technology Platform (SNETP) considers a prototype SFR to be built as a next-step towards the deployment of a first-of-a-kind Gen IV SFR. This paper gives an overview of current research preformed at JRC-IE with emphasis on the work performed in the Collaborative Project on European Sodium Fast Reactor (CP-ESFR) within the European Commission's Seventh Framework Program. (authors)

  17. Overview of nuclear safety activities performed by JRC-IE on Gen IV fast reactor concepts

    International Nuclear Information System (INIS)

    Tsige-Tamirat, H.; Ammirabile, L.; D'Agata, E.; Fuetterer, M.; Ranguelova, V.

    2010-01-01

    The European Strategic Energy Technology (SET) Plan recognizes the need to develop new energy technologies, in order to reduce greenhouse gas emissions and secure energy supply in Europe. Besides renewable energy and improved energy efficiency, a new generation of nuclear power plants and innovative nuclear power applications can play a significant role to achieve this goal. The JRC Institute for Energy 'Safety of Future Nuclear Reactors' (SFNR) Unit is engaged in experimental research, numerical simulation and modelling, scientific, feasibility and engineering studies on innovative nuclear reactor systems. This also represents a significant EURATOM contribution to the Generation IV International Forum. Its activities deal with, among others, the performance assessment of innovative fuels and materials, development of new reactor core concepts and safety solutions, and knowledge management and preservation. Special attention is given to fast reactor concepts, namely the sodium (SFR) and lead (LFR) cooled reactors. Recognizing the maturity of the SFR technology, the European Sustainable Nuclear Energy Technology Platform (SNETP) considers a prototype SFR to be built as a next-step towards the deployment of a first-of-a-kind Gen IV SFR. This paper gives an overview of current research preformed at JRC-IE with emphasis on the work performed in the Collaborative Project on European Sodium Fast Reactor (CP-ESFR) within the European Commission's Seventh Framework Program. (authors)

  18. Gen IV International Forum - GIF, 2010 Annual Report

    International Nuclear Information System (INIS)

    Anon.

    2011-01-01

    being down for 15 years, and the China experimental fast reactor (CEFR) reached its first criticality in July. Despite the closure of PBMR, projects for new VHTR are ongoing, including the HTR-PM in China, now ready for construction, and the NGNP in United States, while the HTTR prototype in Japan achieved successfully 50 days of continuous operation at 950 deg. C. This fourth GIF Annual Report includes four chapters in addition to this introduction plus three appendices. Chapter 2 describes the membership and organization of GIF, the structure of its cooperative research and development arrangements as well as the status of members' participation in such arrangements. Chapter 3 summarizes GIF R and D plans, activities and achievements during 2010. It highlights the R and D challenges facing the teams developing Generation IV systems and the major milestones towards the development of these systems. It also describes the progress made on the development of methodologies for assessing Generation IV systems with respect to the established goals of GIF. Chapter 4 reviews the cooperation between GIF and other international programs dealing with the development of nuclear energy. Appendix 1 provides an overview on the goals of Generation IV nuclear energy systems and an outline of the main characteristics of the six systems selected for joint development by GIF. Appendix 2 presents the objectives that have been set for the various System Steering Committees and the associated Project Management Boards for the period extending from 2010 to 2015. Finally, Appendix 3 provides a list of abbreviations and acronyms (with the corresponding definitions) which are used in this report or are relevant to GIF activities

  19. Development of Basic Key Technologies for Gen IV SFR Safety Evaluation

    International Nuclear Information System (INIS)

    Jeong, Hae Yong; Kwon, Young Min; Kim, Tae Woon; Park, Soo Yong; Suk, Soo Dong; Lee, Kwi Lim; Lee, Yong Bum; Chang, Won Pyo; Ha, Kwi Seok; Hahn, Sang Hoon

    2010-07-01

    Safety issues and design requirements on control rod worth were identified through the evaluation of safety design characteristics and the preliminary safety evaluation. This results will be taken into account for the conceptual design studies of the demonstration reactor in the next stage. The Level-1 Pasa has been performed and a quantitative Cdf value was produced for the selected design from the several candidates. The inherent safety characteristics of the selected design were evaluated through the DBE and ATWS analyses. A surrogate material for Tru has been selected which is applicable to the study of liquidus/solidus temperature test for the metallic fuel containing Tru. A methodology for the regression analysis with surrogate material has been developed and valuable data on metal fuel liquidus/solidus temperature have been measured. A simple mechanistic model describing a bending of subassemblies has been formulated based on the foreign test data and existing models. Its applicability has been evaluated for the Phenix design. New criteria of the core damage for the SFR PSA were identified. The list of initiating events, system response event tree, and core response event tree, which constitute a PSA methodology for an SFR, have been introduced. By developing the SFR PIRT, phenomenological model features, which have to be satisfied in a safety code, were defined and the PIRT results were applied to the design of the PDRC test facility. Bases for a safety evaluation methodology for the SFR DBEs have been also prepared. A draft version of the topical report on the code for local fault analysis has been completed. Since 2007, the MARS-LMR code has been developed and assessments for model validation with the test data from EBR-II and Phenix reactor have been continued. The code has been applied to the evaluation of passive safety of a conceptual design of Gen IV SFR

  20. Development of Basic Key Technologies for Gen IV SFR

    International Nuclear Information System (INIS)

    Han, Do Hee; Kim, Young In; Won, Byung Chool

    2008-11-01

    Technical specifications such as power capacity, type of core, clad alloy, clad barrier material, number of loops, type of SG tube have been evaluated and a optimal design concept has been identified to satisfy the technology goals of Generation IV nuclear systems. The concept for breakeven design is featured by the heat capacity of 1,200 MWe, enrichment-separated core, 2-loop, double-walled SG tube, and a long-life sensor system for in-service inspection

  1. Thermal stability study for candidate stainless steels of GEN IV reactors

    International Nuclear Information System (INIS)

    Simeg Veternikova, J.; Degmova, J.; Pekarcikova, M.; Simko, F.; Petriska, M.; Skarba, M.; Mikula, P.; Pupala, M.

    2016-01-01

    Highlights: • Thermal resistance of advanced stainless steels were observed at 1000 °C. • GEN IV candidate steels were confronted to classic AISI steels. • ODS AISI 316 has weaker thermal resistance than classic AISI steel. • Ferritic ODS steels and NF 709 has better thermal resistance than AISI steels. - Abstract: Candidate stainless steels for GEN IV reactors were investigated in term of thermal and corrosion stability at high temperatures. New austenitic steel (NF 709), austenitic ODS steel (ODS 316) and two ferritic ODS steels (MA 956 and MA 957) were exposed to around 1000 °C in inert argon atmosphere at pressure of ∼8 MPa. The steels were further studied in a light of vacancy defects presence by positron annihilation spectroscopy and their thermal resistance was confronted to classic AISI steels. The thermal strain supported a creation of oxide layers observed by scanning electron microscopy (SEM).

  2. Thermal stability study for candidate stainless steels of GEN IV reactors

    Energy Technology Data Exchange (ETDEWEB)

    Simeg Veternikova, J., E-mail: jana.veternikova@stuba.sk [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Degmova, J. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Pekarcikova, M. [Institute of Materials Science, Faculty of Materials Science and Technology, Slovak University of Technology, Paulinska 16, 917 24 Trnava (Slovakia); Simko, F. [Department of Molten Salts, Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, 845 36 Bratislava (Slovakia); Petriska, M. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Skarba, M. [Slovak University of Technology, Vazovova 5, 812 43 Bratislava (Slovakia); Mikula, P. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Pupala, M. [Department of Molten Salts, Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, 845 36 Bratislava (Slovakia)

    2016-11-30

    Highlights: • Thermal resistance of advanced stainless steels were observed at 1000 °C. • GEN IV candidate steels were confronted to classic AISI steels. • ODS AISI 316 has weaker thermal resistance than classic AISI steel. • Ferritic ODS steels and NF 709 has better thermal resistance than AISI steels. - Abstract: Candidate stainless steels for GEN IV reactors were investigated in term of thermal and corrosion stability at high temperatures. New austenitic steel (NF 709), austenitic ODS steel (ODS 316) and two ferritic ODS steels (MA 956 and MA 957) were exposed to around 1000 °C in inert argon atmosphere at pressure of ∼8 MPa. The steels were further studied in a light of vacancy defects presence by positron annihilation spectroscopy and their thermal resistance was confronted to classic AISI steels. The thermal strain supported a creation of oxide layers observed by scanning electron microscopy (SEM).

  3. GIF (Gen-IV International Forum) Symposium 2009. Proceedings

    International Nuclear Information System (INIS)

    2009-01-01

    The objective of this symposium is to give a well documented state of the art of the initiative and to report and discuss the most significant technical progress and evolution in the different areas during these last ten years. Another significant objective is to provide a forum for an open and hopefully lively discussion of the perspectives, priorities and challenges for the next few years, accounting for a rapidly evolving environment. The symposium has been organized into three sessions that have dealt with the following issues: -) Generation IV International Forum (GIF): 10 years of achievements and the path forward, -) Methodology Overviews and Focus on Applications, -) Very High Temperature Reactor (VHTR), -) Gas-cooled Fast Reactor (GFR), -) Super-Critical Water-cooled Reactor (SCWR), -) Lead-cooled Fast Reactor (LFR), -) Molten Salt Reactor (MSR), -) Sodium-cooled Fast Reactor (SFR), -) International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) and its potential synergy with GIF, and -) GIF priority objectives for the next 5 years

  4. Development of basic key technologies for Gen IV SFR

    International Nuclear Information System (INIS)

    Kim, Yeongil; Kim, Sungoh; Choi, Sukgi

    2012-04-01

    The advanced concepts, for the breakeven reactor(1,200MWe) and TRU burner(600MWe), were defined to satisfy the technology goals of Generation IV nuclear systems. Based on the advanced design concepts, a conceptual design of the demonstration SFR has been developed using the available licensing technology. The conceptual core design has been developed for the TRU burner in which an initial core is fueled with less than 20wt% enriched U235, and finally transformed to a self-recycled TRU core. The passive decay heat removal circuit ensuring reactor safety even in case of loss of emergency power has been developed and minimization of a reactor vessel and simplification of reactor internals have been conducted in the conceptual design. For development of advanced technologies, control logics for various power levels and the optimal design concept of heat exchanger applicable to supercritical CO 2 Brayton cycle as an energy conversion system was developed. A novel under-sodium waveguide sensor and a prototype under-sodium inspection system have been developed for under-sodium viewing of in-vessel structures submerged in an opaque liquid sodium. The fabrication technology of fuel slugs using the advanced fuel slug casting system was developed, and U-Zr alloy fuel rods were fabricated and examined. And a HT 9 cladding tube was manufactured using the developed cladding tube fabrication technology. For development of basic technologies, the cross section adjustment code ATCROSS and the MATRA-LMR code with HCFs have been developed to reduce core design uncertainties. The SIE ASME-NH computer program to evaluate high temperature structural design for 60 years design life, and the safety analysis code MARS-LMR with thermal-hydraulic and reactivity feedback models have been developed and validated. In addition, the sodium impurity measurement and control technology, the sodium water reaction event propagation model to predict the sodium leak propagation in a steam generator, and

  5. GEN IV: Carbide Fuel Elaboration for the 'Futurix Concepts' experiment

    International Nuclear Information System (INIS)

    Vaudez, Stephane; Riglet-Martial, Chantal; Paret, Laurent; Abonneau, Eric

    2008-01-01

    In order to collect information on the behaviour of the future GFR (Gas Fast Reactor) fuel under fast neutron irradiation, an experimental irradiation program, called 'Futurix-concepts' has been launched at the CEA. The considered concept is a composite material made of a fissile fuel embedded in an inert ceramic matrix. Fissile fuel pellets are made of UPuN or UPuC while ceramics are SiC for the carbide fuel and TiN for the nitride fuel. This paper focuses on the description of the carbide composite fabrication. The UPuC pellets are manufactured using a metallurgical powder process. Fabrication and handling of the fuels are carried out in glove boxes under a nitrogen atmosphere. Carbide fuel is synthesized by carbo-thermic reduction under vacuum of a mixture of actinide oxide and graphitic carbon up to 1550 deg. C. After ball milling, the UPuC powder is pressed to create hexagonal or spherical compacts. They are then sintered up to 1750 deg. C in order to obtain a density of 85 % of the theoretical one. The sintered pellets are inserted into an inert and tight capsule of SiC. In order to control the gap between the fuel and the matrix precisely, the pellets are abraded. The inert matrix is then filled with the pellets and the whole system is sealed by a BRASiC R process at high temperature under a helium atmosphere. Fabrication of the sample to be irradiated was done in 2006 and the irradiation began in May 2007 in the Phenix reactor. This presentation will detail and discuss the results obtained during this fabrication phase. (authors)

  6. Conceptual Design on Primary Control Rod Drive Mechanism of a Prototype Gen-IV SFR

    International Nuclear Information System (INIS)

    Lee, Jae Han; Koo, Gyeong Hoi

    2013-01-01

    This paper describes the key concept of the drive mechanism, and suggests a required motor power and reducer gears to meet the functional design requirements, and a seismic response analysis of CRDM housing is performed to check its structural integrity. An AC servo motor is selected as a CRA driving power because it uses permanent magnets and is brushless type while DC motor needs a brush and a coil rotates. The control shim motor size is constrained by a housing diameter of 250mm. The driving system has several design requirements. To calculate the motor power, the drive shaft torque is needed. One part of the drive shaft has a lead screw, driving by a ball-nut. The ball screw driver torque (Tr) is calculated by some equations as follow; A servo motor with a nominal power of 100W, a nominal torque of 0.32 N-m (max. 0.48N-m) is selected considering a safety margin. Its diameter is about 50mm. The fast drive-in motor needs a strong power to insert enforcedly the stuck CRA into core within a required time. The motor sizes are calculated by the same procedure. The diameters are in the range of 80mm to 110mm by the insertion time (10 ∼ 24 seconds). The prototype Gen-IV SFR (sodium-cooled Fast Reactor) is of 150MWe capacity. The reactor has six primary control rod assemblies(CRAs). The primary control rod is used for power control, burn-up compensation and reactor shutdown in response to demands from the plant control or protection systems. The control rod drive mechanism (CRDM) consists of the drive motor assembly, the driveline, and its housing. The driveline consists of three concentric members of a drive shaft, a tension tube, and a position indicator rod, and it connects the drive motor assembly to the CRA. Main issue is that these many driving parts shall be enclosed within a limited housing diameter because the available pitch of CRDMs is limited by 300mm

  7. Conceptual Design on Primary Control Rod Drive Mechanism of a Prototype Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Han; Koo, Gyeong Hoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    This paper describes the key concept of the drive mechanism, and suggests a required motor power and reducer gears to meet the functional design requirements, and a seismic response analysis of CRDM housing is performed to check its structural integrity. An AC servo motor is selected as a CRA driving power because it uses permanent magnets and is brushless type while DC motor needs a brush and a coil rotates. The control shim motor size is constrained by a housing diameter of 250mm. The driving system has several design requirements. To calculate the motor power, the drive shaft torque is needed. One part of the drive shaft has a lead screw, driving by a ball-nut. The ball screw driver torque (Tr) is calculated by some equations as follow; A servo motor with a nominal power of 100W, a nominal torque of 0.32 N-m (max. 0.48N-m) is selected considering a safety margin. Its diameter is about 50mm. The fast drive-in motor needs a strong power to insert enforcedly the stuck CRA into core within a required time. The motor sizes are calculated by the same procedure. The diameters are in the range of 80mm to 110mm by the insertion time (10 ∼ 24 seconds). The prototype Gen-IV SFR (sodium-cooled Fast Reactor) is of 150MWe capacity. The reactor has six primary control rod assemblies(CRAs). The primary control rod is used for power control, burn-up compensation and reactor shutdown in response to demands from the plant control or protection systems. The control rod drive mechanism (CRDM) consists of the drive motor assembly, the driveline, and its housing. The driveline consists of three concentric members of a drive shaft, a tension tube, and a position indicator rod, and it connects the drive motor assembly to the CRA. Main issue is that these many driving parts shall be enclosed within a limited housing diameter because the available pitch of CRDMs is limited by 300mm.

  8. Gen IV Materials Handbook Functionalities and Operation (2B) Handbook Version 2.0

    International Nuclear Information System (INIS)

    Ren, Weiju

    2011-01-01

    This document is prepared for navigation and operation of the Gen IV Materials Handbook, with architecture description and new user access initiation instructions. Development rationale and history of the Handbook is summarized. The major development aspects, architecture, and design principles of the Handbook are briefly introduced to provide an overview of its past evolution and future prospects. Detailed instructions are given with examples for navigating the constructed Handbook components and using the main functionalities. Procedures are provided in a step-by-step fashion for Data Upload Managers to upload reports and data files, as well as for new users to initiate Handbook access.

  9. Gen IV Materials Handbook Functionalities and Operation (4A) Handbook Version 4.0

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL

    2013-09-01

    This document is prepared for navigation and operation of the Gen IV Materials Handbook, with architecture description and new user access initiation instructions. Development rationale and history of the Handbook is summarized. The major development aspects, architecture, and design principles of the Handbook are briefly introduced to provide an overview of its past evolution and future prospects. Detailed instructions are given with examples for navigating the constructed Handbook components and using the main functionalities. Procedures are provided in a step-by-step fashion for Data Upload Managers to upload reports and data files, as well as for new users to initiate Handbook access.

  10. Gen IV Materials Handbook Functionalities and Operation (2B) Handbook Version 2.0

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL

    2011-08-01

    This document is prepared for navigation and operation of the Gen IV Materials Handbook, with architecture description and new user access initiation instructions. Development rationale and history of the Handbook is summarized. The major development aspects, architecture, and design principles of the Handbook are briefly introduced to provide an overview of its past evolution and future prospects. Detailed instructions are given with examples for navigating the constructed Handbook components and using the main functionalities. Procedures are provided in a step-by-step fashion for Data Upload Managers to upload reports and data files, as well as for new users to initiate Handbook access.

  11. Progress reports for Gen IV sodium fast reactor activities FY 2007

    International Nuclear Information System (INIS)

    Cahalan, J. E.; Tentner, A. M.

    2007-01-01

    for prevention of progression into severe accident conditions (prevention of core melting) or for mitigation of severe accident consequences (mitigation of the impact of core melting to protect public health and safety). Because design measures for severe accident prevention and mitigation are beyond the normal design basis, established regulatory guidelines and codes do not provide explicit identification of the design performance requirements for severe accident accommodation. The treatment of severe accidents is one of the key issues of R and D plans for the Gen IV systems in general, and for the Sodium Fast Reactor (SFR) in particular. Despite the lack of an unambiguous definition of safety approach applicable for severe accidents, there is an emerging consensus on the need for their consideration for the design. The US SFR program and Argonne National Laboratory (ANL) in particular have actively studied the potential scenarios and consequences of Hypothetical Core Disruptive Accidents (HCDA) for SFRs with oxide fuel during the Fast Flux Test Facility (FFTF) and Clinch River Breeder Reactor Plant (CRBRP) programs in the 70s and 80s. Later, the focus of the US SFR safety R and D activities shifted to the prevention of all HCDAs through passive safety features of the SFRs with metal fuel in the Integral Fast Reactor (IFR) program, and the study of severe accident consequences was de-emphasized. The goal of this paper is to provide an overview of the current SFR safety approach and the role of severe accidents in Japan and France, in preparation for an expected and more active collaboration in this area between the US, Japan, and France

  12. Summary of Structural Concept Development and High Temperature Structural Integrity Evaluation Technology for a Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Han; Joo, Young Sang; Lee, Hyeong Yeon (and others)

    2008-04-15

    The economic improvement is a hot issue as one of Gen IV nuclear plant goals. It requires many researches and development works to meet the goal by securing the same level of plant safety. One of the key research items is the increase of the plant capacity with the minimum number of components and loops. Through the successful conceptual design experience for the KALIMER-600, the structural design study for a 1200MWe large capacity of sodium-cooled fast reactor has been performed to achieve the above plant size effects. The component number and reactor structural sizing were determined based on the core and fluid system design information. Several researches were performed to reduce the construction cost of NSSS in structural point of view, for example, a simplified component arrangement, concept proposals of integrated components, a high temperature LBB application technology, and an innovative in-service inspection (ISI) tool, and a computer program development of the ASME-NH design procedure of the class 1 structure and component under high temperature over 500 .deg. C. The IHTS piping arrangement was also proposed to minimize the length through the properly locating the SG and pump by 126m. Further studies of these concepts are required to confirm on the fabricability and the structural integrity for the operating and design loads. The proposed concepts will be optimized to a unified conceptual design through several trade-off studies.

  13. Environmental sensitivity studies for Gen-IV roadmap fast reactor scenario

    International Nuclear Information System (INIS)

    Jeong, Chang Joon

    2004-03-01

    The environmental effect of the self-sufficient fast reactor scenario, which is considered as one of the full fissile plutonium and transuranic recycle scenario in Gen-IV roadmap, has been analyzed by using the dynamic analysis method. Through the parametric calculations for the fast reactor deployment time and capacity, the environmental effects of the fuel cycle for important parameters such as the amount of spent fuel and the combined amounts of plutonium and minor actinides were estimated and compared to those of the once-through LWR fuel cycle. The results of the sensitivity calculations showed that an early deployment of the fast reactor with a high capacity can reduce the accumulation of spent fuel by up to 37%. Furthermore, the recycling of plutonium and minor actinides can reduce the key repository parameter (long term decay heat). Therefore the favorable environmental effects can be expected with the implementation of the symbiotic fast reactor scenario

  14. Mechanical Design Concept of Fuel Assembly for Prototype GEN-IV Sodium-cooled Fast Reactor

    International Nuclear Information System (INIS)

    Yoon, K. H.; Lee, C. B.

    2014-01-01

    The prototype GEN-IV sodium-cooled fast reactor (PGSFR) is an advanced fast reactor plant design that utilizes compact modular pool-type reactors sized to enable factory fabrication and an affordable prototype test for design certification at minimum cost and risk. The design concepts of the fuel assembly (FA) were introduced for a PGSFR. Unlike that for the pressurized water reactor, there is a neutron shielding concept in the FA and recycling metal fuel. The PGSFR core is a heterogeneous, uranium-10% zirconium (U-10Zr) metal alloy fuel design with 112 assemblies: 52 inner core fuel assemblies, 60 outer core fuel assemblies, 6 primary control assemblies, 3 secondary control assemblies, 90 reflector assemblies and 102 B4C shield assemblies. This configuration is shown in Fig. 1. The core is designed to produce 150 MWe with an average temperature rise of 155 .deg. C. The inlet temperature is 390 .deg. C and the bulk outlet temperature is 545 .deg. C. The core height is 900 mm and the gas plenum length is 1,250 mm. A mechanical design of a fuel assembly for a PGSFR was established. The mechanical design concepts are well realized in the design. In addition to this, the analytical and experimental works will be carries out for verifying the design soundness

  15. Mechanical Design Concept of Fuel Assembly for Prototype GEN-IV Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, K. H.; Lee, C. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The prototype GEN-IV sodium-cooled fast reactor (PGSFR) is an advanced fast reactor plant design that utilizes compact modular pool-type reactors sized to enable factory fabrication and an affordable prototype test for design certification at minimum cost and risk. The design concepts of the fuel assembly (FA) were introduced for a PGSFR. Unlike that for the pressurized water reactor, there is a neutron shielding concept in the FA and recycling metal fuel. The PGSFR core is a heterogeneous, uranium-10% zirconium (U-10Zr) metal alloy fuel design with 112 assemblies: 52 inner core fuel assemblies, 60 outer core fuel assemblies, 6 primary control assemblies, 3 secondary control assemblies, 90 reflector assemblies and 102 B4C shield assemblies. This configuration is shown in Fig. 1. The core is designed to produce 150 MWe with an average temperature rise of 155 .deg. C. The inlet temperature is 390 .deg. C and the bulk outlet temperature is 545 .deg. C. The core height is 900 mm and the gas plenum length is 1,250 mm. A mechanical design of a fuel assembly for a PGSFR was established. The mechanical design concepts are well realized in the design. In addition to this, the analytical and experimental works will be carries out for verifying the design soundness.

  16. Level II Probabilistic Safety Analysis Methodology for the Application to GEN-IV Sodium-cooled Fast Reactor

    International Nuclear Information System (INIS)

    Park, S. Y.; Kim, T. W.; Han, S. H.; Jeong, H. Y.

    2010-03-01

    The Korea Atomic Energy Research Institute (KAERI) has been developing liquid metal reactor (LMR) design technologies under a National Nuclear R and D Program. Nevertheless, there is no experience of the probabilistic safety assessment (PSA) domestically for a fast reactor with the metal fuel. Therefore, the objective of this study is to establish the methodologies of risk assessment for the reference design of GEN-IV sodium fast reactor (SFR). An applicability of the PSA methodology of U. S. NRC and PRISM plant to the domestic GEN-IV SFR has been studied. The study contains a plant damage state analysis, a containment event tree analysis, and a source-term release category binning process

  17. The ENEN-III project: Technical Training on the Concepts and Design of GEN IV nuclear reactors

    International Nuclear Information System (INIS)

    Berkvens, T.; Renault, C.; Alonso, M.; Salomaa, R.; Schönfelder, C.

    2013-01-01

    Some conclusions: • Not enough training courses to cover the LO’s: – Especially GEN IV; – Many introductory courses, little specific courses; – Reach out to other partners for more courses. • Skills and Attitudes: – Much more difficult to train/measure; – To be treated in a separate project. • Use of Learning Outcomes must be promoted; • Involvement of human resources necessary for the successful implementation of the schemes: – End of project workshop

  18. A Qualitative Assessment of Diversion Scenarios for a GEN IV Example Sodium Fast Reactor Using the GEN IV PR and PP Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Zentner, M.D.; Coles, G.A. [PNNL, P.O. Box 999, 902 Battelle Boulvard, Richland, WA 99336 (United States); Therios, I.U. [Argonne National Lab. - ANL (United States)

    2009-06-15

    An experts working group was created in 2002 by The Generation IV International Forum for the purpose of developing an internationally accepted methodology for assessing the proliferation resistance of a nuclear energy system (NES) and its individual elements. A two year case study was performed by the working group using this methodology to assess the proliferation resistance of a hypothetical NES called the Example Sodium Fast Reactor (ESFR). This work demonstrates how the PR and PP methodology can be used to provide important information to designers at various levels of details, including pre-conceptual design stage. The study analyzes the response of the ESFR entire nuclear energy system to different proliferation and theft strategies. The challenges considered comprise concealed diversion, concealed misuse and abrogation strategies. This paper describes the work done in performing a qualitative assessment of potential concealed diversion scenarios from the ESFR, and includes an evaluation of the potential effect of changes in the conversion ratio on diversion strategies. (authors)

  19. Multi-criteria methodology to design a sodium-cooled carbide-fueled Gen-IV reactor

    International Nuclear Information System (INIS)

    Stauff, N.

    2011-01-01

    Compared with earlier plant designs (Phenix, Super-Phenix, EFR), Gen IV Sodium-cooled Fast Reactor requires improved economics while meeting safety and non-proliferation criteria. Mixed Oxide (U-Pu)O 2 fuels are considered as the reference fuels due to their important and satisfactory feedback experience. However, innovative carbide (U-Pu)C fuels can be considered as serious competitors for a prospective SFR fleet since carbide-fueled SFRs can offer another type of optimization which might overtake on some aspects the oxide fuel technology. The goal of this thesis is to reveal the potentials of carbide by designing an optimum carbide-fueled SFR with competitive features and a naturally safe behavior during transients. For a French nuclear fleet, a 1500 MW(e) break-even core is considered. To do so, a multi-physic approach was developed taking into account neutronics, fuel thermo-mechanics and thermal-hydraulic at a pre-design stage. Simplified modeling with the calculation of global neutronic feedback coefficients and a quasi-static evaluation was developed to estimate the behavior of a core during overpower transients, loss of flow and/or loss of heat removal transients. The breakthrough of this approach is to provide the designer with an overall view of the iterative process, emphasizing the well-suited innovations and the most efficient directions that can improve the SFR design project.This methodology was used to design a core that benefits from the favorable features of carbide fuels. The core developed is a large carbide-fueled SFR with high power density, low fissile inventory, break-even capability and forgiving behaviors during the un-scrammed transients studied that should prevent using expensive mitigate systems. However, the core-peak burnup is unlikely to significantly exceed 100 MWd/kg because of the large swelling of the carbide fuel leading to quick pellet-clad mechanical interaction and the low creep capacity of carbide. Moderate linear power fuel

  20. Innovative materials for GEN IV systems and transmutation facilities (cross-cutting research project GETMAT)

    International Nuclear Information System (INIS)

    Fazio, Concetta; Rieth, Michael; Gomez Briceno, Dolores; Gessi, Alessandro; Henry, Jean; Malerba, Lorenzo

    2010-01-01

    The objectives of the 'Generation IV and Transmutation Materials' (GETMAT) project is to contribute to the development, qualification and ranking of different types of ODS steels and to qualify Ferritic/Martensitic steels in a wide irradiation condition range. The experimental approach is complemented by the development of physical models with the aim to understand and improve the predictability of the materials performance. The GETMAT consortium is composed of fourteen Research centres, nine Universities and one Utility, from eleven European countries. The R and D tasks address (i) the materials availability, fabricability, weldability and their fundamental mechanical properties, (ii) their compatibility with aggressive coolants and development of corrosion protection methods; (iii) their performance under neutron irradiation, and (iv) starting from model alloys relevant for the two classes of alloys, the development and validation of physical models. The exploitation of results to potential end-users will occur through the 'GETMAT User Group', where exchange of information with the nuclear and steel industries, international (outside Europe) Research Organisations and engineers involved in the design of the new reactors, will occur. The exploitation of results to potential end-users will occur through the G ETMAT User Group , where exchange of information with the nuclear and steel industries, international (outside Europe) Research Organisations and engineers involved in the design of the new reactors, will occur

  1. On the safety and performance demonstration tests of Prototype Gen-IV Sodium-Cooled Fast Reactor and validation and verification of computational codes

    International Nuclear Information System (INIS)

    Kim, Jong Bum; Jeong, Ji Young; Lee, Tae Ho; Kim, Sung Kyun; Euh, Dong Jin; Joo, Hyung Kook

    2016-01-01

    The design of Prototype Gen-IV Sodium-Cooled Fast Reactor (PGSFR) has been developed and the validation and verification (V and V) activities to demonstrate the system performance and safety are in progress. In this paper, the current status of test activities is described briefly and significant results are discussed. The large-scale sodium thermal-hydraulic test program, Sodium Test Loop for Safety Simulation and Assessment-1 (STELLA-1), produced satisfactory results, which were used for the computer codes V and V, and the performance test results of the model pump in sodium showed good agreement with those in water. The second phase of the STELLA program with the integral effect tests facility, STELLA-2, is in the detailed design stage of the design process. The sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger performance test, the intermediate heat exchanger test facility, and the test facility for the reactor flow distribution are underway. Flow characteristics test in subchannels of a wire-wrapped rod bundle has been carried out for safety analysis in the core and the dynamic characteristic test of upper internal structure has been performed for the seismic analysis model for the PGSFR. The performance tests for control rod assemblies (CRAs) have been conducted for control rod drive mechanism driving parts and drop tests of the CRA under scram condition were performed. Finally, three types of inspection sensors under development for the safe operation of the PGSFR were explained with significant results

  2. On the safety and performance demonstration tests of Prototype Gen-IV Sodium-Cooled Fast Reactor and validation and verification of computational codes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Bum; Jeong, Ji Young; Lee, Tae Ho; Kim, Sung Kyun; Euh, Dong Jin; Joo, Hyung Kook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The design of Prototype Gen-IV Sodium-Cooled Fast Reactor (PGSFR) has been developed and the validation and verification (V and V) activities to demonstrate the system performance and safety are in progress. In this paper, the current status of test activities is described briefly and significant results are discussed. The large-scale sodium thermal-hydraulic test program, Sodium Test Loop for Safety Simulation and Assessment-1 (STELLA-1), produced satisfactory results, which were used for the computer codes V and V, and the performance test results of the model pump in sodium showed good agreement with those in water. The second phase of the STELLA program with the integral effect tests facility, STELLA-2, is in the detailed design stage of the design process. The sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger performance test, the intermediate heat exchanger test facility, and the test facility for the reactor flow distribution are underway. Flow characteristics test in subchannels of a wire-wrapped rod bundle has been carried out for safety analysis in the core and the dynamic characteristic test of upper internal structure has been performed for the seismic analysis model for the PGSFR. The performance tests for control rod assemblies (CRAs) have been conducted for control rod drive mechanism driving parts and drop tests of the CRA under scram condition were performed. Finally, three types of inspection sensors under development for the safe operation of the PGSFR were explained with significant results.

  3. Design and Selection of Innovative Primary Circulation Pumps for GEN-IV Lead Fast Reactors

    Directory of Open Access Journals (Sweden)

    Walter Borreani

    2017-12-01

    Full Text Available Although Lead-cooled Fast Reactor (LFR is not a new concept, it continues to be an example of innovation in the nuclear field. Recently, there has been strong interest in liquid lead (Pb or liquid lead–bismuth eutectic (LBE both critical and subcritical systems in a relevant number of Countries, including studies performed in the frame of GENERATION-IV initiative. In this paper, the theoretical and computational findings for three different designs of Primary Circulation Pump (PCP evolving liquid lead (namely the jet pump, the Archimedean pump and the blade pump are presented with reference to the ALFRED (Advanced Lead Fast Reactor European Demonstrator design. The pumps are first analyzed from the theoretical point of view and then modeled with a 3D CFD code. Required design performance of the pumps are approximatively around an effective head of 2 bar with a mass flow rate of 5000 kg/s. Taking into account the geometrical constraints of the reactor and the fluid dynamics characteristics of the molten lead, the maximum design velocity for molten lead fluid flow of 2 m/s may be exceeded giving rise to unacceptable erosion phenomena of the blade or rotating component of the primary pumping system. For this reason a deep investigation of non-conventional axial pumps has been performed. The results presented shows that the design of the jet pump looks like beyond the current technological feasibility while, once the mechanical challenges of the Archimedean (screw pump and the fluid-dynamic issues of the blade pump will be addressed, both could represent viable solutions as PCP for ALFRED. Particularly, the blade pump shows the best performance in terms of pressure head generated in normal operation conditions as well as pressure drop in locked rotor conditions. Further optimizations (mainly for what the geometrical configuration is concerned are still necessary.

  4. Unprotected Accident Analyses of the 1200MWe GEN-IV Sodium-Cooled Fast Reactor Using the SSC-K Code

    International Nuclear Information System (INIS)

    Kwon, Young Min; Lee, Kwi Lim; Ha, Kwi Seok; Jeong, Hae Yong; Chang, Won Pyo; Seok, Su Dong; Lee, Yong Bum

    2010-02-01

    A conceptual design of an advanced breakeven sodium-cooled fast reactor (G4SFR) has recently been developed by KAERI under the national nuclear R and D plan. The G4SFR is a 1,200MWe metal-fueled pool-type sodium-cooled fast reactor adopting advanced safety design features. The G4SFR development plan focuses on particular technology development efforts to effectively meet the goals of the Generation-IV (GEN-IV) nuclear system such as efficient utilization of resources, economic competitiveness, a high standard of safety, and enhanced proliferation resistance. To enhance the safety of G4SFR, advanced design features of metal-fueled core, simple and large sodium-inventory primary heat transport system, and passive safety decay heat removal system are included in the reactor design. To evaluate potential safety characteristics of such advanced design features, the plant responses and safety margins were investigated using the system transient code SSC-K for three unprotected accidents of UTOP, ULOF, and ULOHS. It was shown that the G4SFR design has inherent and passive safety characteristics and is accommodating the selected ATWS events. The inherent safety mechanism of the reactor design makes the core shutdown with sufficient margin and passive removal of decay heat with matching the core power to heat sink by passive self-regulation. The self-regulation of power without scram is mainly due to the inherent negative reactivity feedback in conjunction with the large thermal inertia of the primary heat transport system and the passive decay heat removal. Such favorable inherent and passive safety behaviors of G4SFR are expected to virtually exclude the probability of severe accidents with potential for core damage

  5. On the Safety and Performance Demonstration Tests of Prototype Gen-IV Sodium-Cooled Fast Reactor and Validation and Verification of Computational Codes

    Directory of Open Access Journals (Sweden)

    Jong-Bum Kim

    2016-10-01

    Full Text Available The design of Prototype Gen-IV Sodium-Cooled Fast Reactor (PGSFR has been developed and the validation and verification (V&V activities to demonstrate the system performance and safety are in progress. In this paper, the current status of test activities is described briefly and significant results are discussed. The large-scale sodium thermal-hydraulic test program, Sodium Test Loop for Safety Simulation and Assessment-1 (STELLA-1, produced satisfactory results, which were used for the computer codes V&V, and the performance test results of the model pump in sodium showed good agreement with those in water. The second phase of the STELLA program with the integral effect tests facility, STELLA-2, is in the detailed design stage of the design process. The sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger performance test, the intermediate heat exchanger test facility, and the test facility for the reactor flow distribution are underway. Flow characteristics test in subchannels of a wire-wrapped rod bundle has been carried out for safety analysis in the core and the dynamic characteristic test of upper internal structure has been performed for the seismic analysis model for the PGSFR. The performance tests for control rod assemblies (CRAs have been conducted for control rod drive mechanism driving parts and drop tests of the CRA under scram condition were performed. Finally, three types of inspection sensors under development for the safe operation of the PGSFR were explained with significant results.

  6. Status of the French R/D program on the severe accident issue to develop Gen IV SFRs - 15373

    International Nuclear Information System (INIS)

    Serre, F.; Bertrand, F.; Journeau, C.; Suteau, C.; Verwaede, D.; Schmitt, D.; Farges, B.

    2015-01-01

    The ASTRID reactor (Advanced Sodium Technological Reactor for Industrial Demonstration) is a technological demonstrator designed by the CEA with its industrial partners, with very high levels of requirements. In the ASTRID project, the safety objectives are to prevent core melting, in particular by the development of an innovative core with complementary safety prevention devices, and to enhance the reactor resistance to severe accident by design. To mitigate the consequences of hypothetical core melting situations, specific dispositions or mitigation devices will be added to the core and to the reactor. It is also required to provide a robust safety demonstration (with high level of confidence). Therefore a new approach for severe accident issue has been defined: to the well-known 'lines of defense' method, a 'lines of mitigation' method is added. To meet these ASTRID, or future SFR, requirements, a large R/D program was launched in the Severe Accident domain, with a large number of partners. This paper will present the status of the CEA R/D related to the SFR Severe Accident issue, the collaboration framework (with industrial partners and R/D foreign organizations), and the future R/D plans to support the ASTRID project and possible developments for future Gen IV commercial SFR. (authors)

  7. Uranium enrichment reduction in the Prototype Gen-IV sodium-cooled fast reactor (PGSFR) with PBO reflector

    Energy Technology Data Exchange (ETDEWEB)

    Hartanto, Donny; Kim, Chi Hyung; Kim, Yong Hee [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of)

    2016-04-15

    The Korean Prototype Gen-IV sodium-cooled fast reactor (PGSFR) is supposed to be loaded with a relatively-costly low-enriched U fuel, while its envisaged transuranic fuels are not available for transmutation. In this work, the U-enrichment reduction by improving the neutron economy is pursued to save the fuel cost. To improve the neutron economy of the core, a new reflector material, PbO, has been introduced to replace the conventional HT9 reflector in the current PGSFR core. Two types of PbO reflectors are considered: one is the conventional pin-type and the other one is an inverted configuration. The inverted PbO reflector design is intended to maximize the PbO volume fraction in the reflector assembly. In addition, the core radial configuration is also modified to maximize the performance of the PbO reflector. For the baseline PGSFR core with several reflector options, the U enrichment requirement has been analyzed and the fuel depletion analysis is performed to derive the equilibrium cycle parameters. The linear reactivity model is used to determine the equilibrium cycle performances of the core. Impacts of the new PbO reflectors are characterized in terms of the cycle length, neutron leakage, radial power distribution, and operational fuel cost.

  8. Enhanced radiation resistance through interface modification of nano-structured steels for Gen IV in-core applications

    International Nuclear Information System (INIS)

    Jang, Jinsung; Kang, Suk Hoon; Kim, Min Chul

    2013-06-01

    This project is to increase radiation tolerance of candidate alloys for Gen IV core component through the optimization of grain size and grain boundary characteristics. The focus is on nanocrystalline metal alloys with a fcc crystal structure. The long-term goal is to design and develop bulk nanostructured austenitic steels with enhanced void swelling resistance and substantial ductility, and to enhance their creep resistance at elevated temperatures via grain boundary engineering. An austenitic stainless steel, HT-UPS (high temperature ultra-fine precipitates strengthened) was developed at ORNL, and is expected to show enhanced void swelling resistance through the trapping of point defects at nanometer-sized carbides. Reducing the grain size and increasing the fraction-induced point defects (due to the increased sink area of the grain boundaries), to make bubble nucleation at the boundaries less likely (by reducing the fraction of high-energy boundaries), and to improve the strength and ductility under radiation by producing a higher density of nanometer sized carbides on the boundaries

  9. Control Rod Withdrawal Events Analyses for the Prototype Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chiwoong; Ha, Kwiseo; Jeong, Taekyeong; Jeong, Jaeho; Chang, Wonpyo; Lee, Seungwon; An, Sangjun; Lee, Kwilim [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    To confirm the limiting condition, based on the maximum allowable reactivity insertion of 0.3 $, three cases from the end of cycle (EOC) are selected. In addition, assuming the failure of CRSS by earthquake, additional cases is defined at beginning of cycle (BOC). When the CRW occurs, the reactor can be protected by plant protection system (PPS). In this study, PPS mechanism is sequentially studied for all initiating events. For design basis accidents (DBA), the reactor can be scrammed by reactor protection system (RPS). The first and seconds RPS signals are checked during transients. When RPS is failed, so called as anticipated transient without scram (ATWS), the reactor will be protected by diverse protection system (DPS). In this study, in order to analyze various initiating events related control rod withdrawal, four kinds of operating condition is defined. TOP events are analyzed using MARS-LMR. The influence of various plant protection system such as RPS and DPS are investigated.

  10. Transportable criticality alarm system

    International Nuclear Information System (INIS)

    Clem, W.E.

    1988-09-01

    The Transportable Criticality Alarm System was developed at the Hanford Site in 1982 to comply with the requirements of US Department of Energy Order DOE 5480.1, 12/18/80, and ANSI/ANS-8.3- 1979. The portable unit that it replaced failed to comply with the new requirements in that it did not provide the necessary warning of malfunctions, nor did it provide the Hanford Site standard criticality alarm signal. Modern technology allowed the Transportable Criticality Alarm System to comply with the criticality requirements cited and to incorporate other features that make it more usable, maintainable, and reliable. The Transportable Criticality Alarm System (TCAS) provides temporary criticality coverage in manned areas where the facility criticality alarm system is not operable. This gamma radiation-sensitive system has been in use for the past 6 yr at the Hanford Site. 2 refs., 4 figs., 1 tab

  11. Status of the Gen-IV Proliferation Resistance and Physical Protection (PRPP) Evaluation Methodology

    International Nuclear Information System (INIS)

    Whitlock, J.; Bari, R.; Peterson, P.; Padoani, F.; Cojazzi, G.G.M.; Renda, G.; ); Cazalet, J.; Haas, E.; Hori, K.; Kawakubo, Y.; Chang, S.; Kim, H.; Kwon, E.-H.; Yoo, H.; Chebeskov, A.; Pshakin, G.; Pilat, J.F.; Therios, I.; Bertel, E.

    2015-01-01

    Methodologies have been developed within the Generation IV International Forum (GIF) to support the assessment and improvement of system performance in the areas safeguards, security, economics and safety. Of these four areas, safeguards and security are the subjects of the GIF working group on Proliferation Resistance and Physical Protection (PRPP). Since the PRPP methodology (now at Revision 6) represents a mature, generic, and comprehensive evaluation approach, and is freely available on the GIF public website, several non-GIF technical groups have chosen to utilize the PRPP methodology for their own goals. Indeed, the results of the evaluations performed with the methodology are intended for three types of generic users: system designers, programme policy makers, and external stakeholders. The PRPP Working Group developed the methodology through a series of demonstration and case studies. In addition, over the past few years various national and international groups have applied the methodology to inform nuclear energy system designs, as well as to support the development of approaches to advanced safeguards. A number of international workshops have also been held which have introduced the methodology to design groups and other stakeholders. In this paper we summarize the technical progress and accomplishments of the PRPP evaluation methodology, including applications outside GIF, and we outline the PRPP methodology's relationship with the IAEA's INPRO methodology. Current challenges with the efficient implementation of the methodology are outlined, along with our path forward for increasing its accessibility to a broader stakeholder audience - including supporting the next generation of skilled professionals in the nuclear non-proliferation field. (author)

  12. Project planning of Gen-IV sodium cooled fast reactor technology

    International Nuclear Information System (INIS)

    Yoo, Jaewoon; Joo, H. K.; Cho, C. H.; Kim, Y. G.; Lee, D. U.; Jin, M. W.

    2013-05-01

    The project program will be established to shorten the design schedule by sharing the design man power and experimental facility, and by introducing the proven technology through international collaboration and the project plan including preliminary specific design, technology validation and fuel design validation plan will be more detail by reviewing the plan at the International Technical Review Meeting (ITRM). Periodic project progress review meeting will be held to find the technical issues and to resolve them. The results of the progress review meeting will be reflected into the final assessment of research project. The project progress review meeting will be held every quarter and external expert will also participate in the meeting. In parallel with the PGSFR development, innovative small modular SFR will be developed aiming to the international nuclear market. The system and component technologies of both system can be shared but innovative concept will be implemented into the design. Ultra long life core design concept and supercritical CO 2 Brayton cycle will be considered as the innovative concept for enhancing the plant economy and safety

  13. Millimeter-Wave Thermal Analysis Development and Application to GEN IV Reactor Materials

    Energy Technology Data Exchange (ETDEWEB)

    Wosko, Paul; Sundram, S. K.

    2012-10-16

    New millimeter-wave thermal analysis instrumentation has been developed and studied for characterization of materials required for diverse fuel and structural needs in high temperature reactor environments such as the Next Generation Nuclear Plant (NGNP). A two-receiver 137 GHz system with orthogonal polarizations for anisotropic resolution of material properties has been implemented at MIT. The system was tested with graphite and silicon carbide specimens at temperatures up to 1300 ºC inside an electric furnace. The analytic and hardware basis for active millimeter-wave radiometry of reactor materials at high temperature has been established. Real-time, non contact measurement sensitivity to anisotropic surface emissivity and submillimeter surface displacement was demonstrated. The 137 GHz emissivity of reactor grade graphite (NBG17) from SGL Group was found to be low, ~ 5 %, in the 500 – 1200 °C range and increases by a factor of 2 to 4 with small linear grooves simulating fracturing. The low graphite emissivity would make millimeter-wave active radiometry a sensitive diagnostic of graphite changes due to environmentally induced stress fracturing, swelling, or corrosion. The silicon carbide tested from Ortek, Inc. was found to have a much higher emissivity at 137 GHz of ~90% Thin coatings of silicon carbide on reactor grade graphite supplied by SGL Group were found to be mostly transparent to millimeter-waves, increasing the 137 GHz emissivity of the coated reactor grade graphite to about ~14% at 1250 ºC.

  14. Project planning of Gen-IV sodium cooled fast reactor technology

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jaewoon; Joo, H. K.; Cho, C. H.; Kim, Y. G.; Lee, D. U.; Jin, M. W.

    2013-05-15

    The project program will be established to shorten the design schedule by sharing the design man power and experimental facility, and by introducing the proven technology through international collaboration and the project plan including preliminary specific design, technology validation and fuel design validation plan will be more detail by reviewing the plan at the International Technical Review Meeting (ITRM). Periodic project progress review meeting will be held to find the technical issues and to resolve them. The results of the progress review meeting will be reflected into the final assessment of research project. The project progress review meeting will be held every quarter and external expert will also participate in the meeting. In parallel with the PGSFR development, innovative small modular SFR will be developed aiming to the international nuclear market. The system and component technologies of both system can be shared but innovative concept will be implemented into the design. Ultra long life core design concept and supercritical CO{sub 2} Brayton cycle will be considered as the innovative concept for enhancing the plant economy and safety.

  15. Minor actinides transmutation potential: state of art for GEN IV sodium cooled fast reactors

    International Nuclear Information System (INIS)

    Buiron, Laurent

    2015-01-01

    In the frame of the R and D program relative to the 1991 French act on nuclear waste management, fast neutron systems have shown relevant characteristics that meet both requirements on sustainable resources management and waste minimization. They also offer flexibility by mean of burner or breeder configurations allowing mastering plutonium inventory without significant impact on core safety. From the technological point of view, sodium cooled fast reactor are considered in order to achieve mean term industrial deployment. The present document summaries the main results of R and D program on minor actinides transmutation in sodium fast reactor since 2006 following recommendation of the first part of the 1991 French act. Both homogeneous and heterogeneous management achievable performances are presented for 'evolutionary' SFR V2B core as well as low void worth CFV core for industrial scale configurations (1500 MWe). Minor actinides transmutation could be demonstrated in the ASTRID reactor with the following configurations: - a 2%vol Americium content for the homogeneous mode, - a 10%vol Americium content for the heterogeneous mode, without any substantial modification of the main core safety parameters and only limited impacts on the associated fuel cycle (manufacturing issues are not considered here). In order to achieve such goal, a wide range of experimental irradiations driven by transmutation scenarios have to be performed for both homogeneous and heterogeneous minor actinides management. (author) [fr

  16. Optimized, Competitive Supercritical-CO2 Cycle GFR for Gen IV Service

    International Nuclear Information System (INIS)

    M.J. Driscoll; P. Hejzlar; G. Apostolakis

    2008-01-01

    An overall plant design was developed for a gas-cooled fast reactor employing a direct supercritical Brayton power conversion system. The most important findings were that (1) the concept could be capital-cost competitive, but startup fuel cycle costs are penalized by the low core power density, specified in large part to satisfy the goal of significant post-accident passive natural convection cooling; (2) active decay heat removal is preferable as the first line of defense, with passive performance in a backup role; (3) an innovative tube-in-duct fuel assembly, vented to the primary coolant, appears to be practicable; and (4) use of the S-Co2 GFR to support hydrogen production is a synergistic application, since sufficient energy can be recuperated from the product H2 and 02 to allow the electrolysis cell to run 250 C hotter than the reactor coolant, and the water boilers can be used for reactor decay heat removal. Increasing core power density is identified as the top priority for future work on GFRs of this type

  17. GEN IV: Carbide Fuel Elaboration for the 'Futurix Concepts' experiment

    Energy Technology Data Exchange (ETDEWEB)

    Vaudez, Stephane; Riglet-Martial, Chantal; Paret, Laurent; Abonneau, Eric [Commissariat a l' Energie Atomique (C.E.A.), Direction de l' Energie Nucleaire, Centre d' Etudes de Cadarache, 13108 Saint Paul lez Durance Cedex (France)

    2008-07-01

    In order to collect information on the behaviour of the future GFR (Gas Fast Reactor) fuel under fast neutron irradiation, an experimental irradiation program, called 'Futurix-concepts' has been launched at the CEA. The considered concept is a composite material made of a fissile fuel embedded in an inert ceramic matrix. Fissile fuel pellets are made of UPuN or UPuC while ceramics are SiC for the carbide fuel and TiN for the nitride fuel. This paper focuses on the description of the carbide composite fabrication. The UPuC pellets are manufactured using a metallurgical powder process. Fabrication and handling of the fuels are carried out in glove boxes under a nitrogen atmosphere. Carbide fuel is synthesized by carbo-thermic reduction under vacuum of a mixture of actinide oxide and graphitic carbon up to 1550 deg. C. After ball milling, the UPuC powder is pressed to create hexagonal or spherical compacts. They are then sintered up to 1750 deg. C in order to obtain a density of 85 % of the theoretical one. The sintered pellets are inserted into an inert and tight capsule of SiC. In order to control the gap between the fuel and the matrix precisely, the pellets are abraded. The inert matrix is then filled with the pellets and the whole system is sealed by a BRASiC{sup R} process at high temperature under a helium atmosphere. Fabrication of the sample to be irradiated was done in 2006 and the irradiation began in May 2007 in the Phenix reactor. This presentation will detail and discuss the results obtained during this fabrication phase. (authors)

  18. Analyses of Design Extended Condition Events for the Prototype Gen-IV SFR

    International Nuclear Information System (INIS)

    Choi, Chiwoong; Jeong, Taekyung; Lee, Kwilim; Jeong, Jaeho; Ha, Kwiseok

    2015-01-01

    In this study, the sensitivity tests are conducted. In the case of the UTOP event, a sensitivity test for the reactivity insertion amount and rate were conducted. This analysis can give a requirement for margin of control rod stop system (CRSS). For example, the CRSS in the PRISM designed based on the 0.4 $ reactivity insertion, which is analyzed with safety analysis of UTOP event. Moreover, the sensitivity tests for weighting factor in the core radial expansion reactivity feedback model were also carried out for all ATWS events. Currently, the reactivity feedback model for the PGSFR is not validated yet. However, the reactivity feedback models in the MARS-LMR are validating with various plant-based data including EBR-II SHRT. The ATWS events for the PGSFR classified in the design extended condition including UTOP, ULOF, and ULOHS are analyzed with MARS-LMR. In this study, the sensitivity tests for reactivity insertion amount and rate in the UTOP event are conducted. The reactivity insertion amount is obviously an influential parameter. The reactivity insertion amount can give a requirement for design of the CRSS, therefore, this sensitivity result is very important to the CRSS. In addition, sensitivity tests for the weighting factor in the radial expansion reactivity model are carried out. The weighting factor for a grid plate, W GP , which means contribution of feedback in the grid plate is changed for all unprotected events. The grid plate expansion is governed by a core inlet temperature. As the W GP is increased, the power in the UTOP and the ULOF is increased, however, the power in the ULOHS is decreased. The higher power during transient means lower reactivity feedback and smaller expansion. Thus, the core outlet temperature rise is dominant in the UTOP and ULOF events, however, the core inlet temperature rise is dominant in the ULOHS. Therefore, the grid plate expansion in the ULOHS is predominant

  19. Sensitivity Tests for the Unprotected Events of the Prototype Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chiwoong; Lee, Kwilim; Jeong, Jaeho; Yu, Jin; An, Sangjun; Lee, Seung Won; Chang, Wonpyo; Ha, Kwiseok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Unprotected Transient Over Power, (UTOP), Unprotected Loss Of Flow (ULOF), and Unprotected Loss Of Heat Sink (ULOHS) are selected as ATWS events. Among these accidents, the ULOF event shows the lowest clad temperature. However, the ULOHS event showed the highest peak clad temperature, due to the positive CRDL/RV expansion reactivity feedback and insufficient DHRS capacity. In this study, the sensitivity tests are conducted. In the case of the UTOP event, a sensitivity test for the reactivity insertion amount and rate were conducted. This analysis can give a requirement for margin of control rod stop system (CRSS). Currently, the reactivity feedback model for the PGSFR is not validated yet. However, the reactivity feedback models in the MARS-LMR are validating with various plant-based data including EBR-II SHRT. The ATWS events for the PGSFR classified in the design extended condition including UTOP, ULOF, and ULOHS are analyzed with MARS-LMR. In this study, the sensitivity tests for reactivity insertion amount and rate in the UTOP event are conducted. The reactivity insertion amount is obviously an influential parameter. The reactivity insertion amount can give a requirement for design of the CRSS, therefore, this sensitivity result is very important to the CRSS. In addition, sensitivity tests for the weighting factor in the radial expansion reactivity model are carried out. The weighting factor for a grid plate, W{sub GP}, which means contribution of feedback in the grid plate is changed for all unprotected events. The grid plate expansion is governed by a core inlet temperature. As the W{sub GP} is increased, the power in the UTOP and the ULOF is increased, however, the power in the ULOHS is decreased. The higher power during transient means lower reactivity feedback and smaller expansion. Thus, the core outlet temperature rise is dominant in the UTOP and ULOF events, however, the core inlet temperature rise is dominant in the ULOHS. Therefore, the grid plate

  20. Minimum critical mass systems

    International Nuclear Information System (INIS)

    Dam, H. van; Leege, P.F.A. de

    1987-01-01

    An analysis is presented of thermal systems with minimum critical mass, based on the use of materials with optimum neutron moderating and reflecting properties. The optimum fissile material distributions in the systems are obtained by calculations with standard computer codes, extended with a routine for flat fuel importance search. It is shown that in the minimum critical mass configuration a considerable part of the fuel is positioned in the reflector region. For 239 Pu a minimum critical mass of 87 g is found, which is the lowest value reported hitherto. (author)

  1. Nuclear criticality information system

    International Nuclear Information System (INIS)

    Koponen, B.L.; Hampel, V.E.

    1981-01-01

    The nuclear criticality safety program at LLNL began in the 1950's with a critical measurements program which produced benchmark data until the late 1960's. This same time period saw the rapid development of computer technology useful for both computer modeling of fissile systems and for computer-aided management and display of the computational benchmark data. Database management grew in importance as the amount of information increased and as experimental programs were terminated. Within the criticality safety program at LLNL we began at that time to develop a computer library of benchmark data for validation of computer codes and cross sections. As part of this effort, we prepared a computer-based bibliography of criticality measurements on relatively simple systems. However, it is only now that some of these computer-based resources can be made available to the nuclear criticality safety community at large. This technology transfer is being accomplished by the DOE Technology Information System (TIS), a dedicated, advanced information system. The NCIS database is described

  2. Critical/non-critical system methodology report

    International Nuclear Information System (INIS)

    1989-01-01

    The method used to determine how the waste Isolation Pilot Plant (WIPP) facilities/systems were classified as critical or non-critical to the receipt of CH waste is described within this report. All WIPP critical facilities/systems are listed in the Operational Readiness Review Dictionary. Using the Final Safety Analysis Report (FSAR) as a guide to define the boundaries of the facilities/systems, a direct correlation of the ORR Dictionary to the FSAR can be obtained. The critical facilities/systems are those which are directly related to or have a critical support role in the receipt of CH waste. The facility/systems must meet one of the following requirements to be considered critical: (a) confinement or measure of the release of radioactive materials; (b) continued receipt and/or storage of transuranic waste (TRU) without an interruption greater than one month according to the shipping plan schedule; (c) the environmental and occupational safety of personnel meets the established site programs; and (d) the physical security of the WIPP facilities

  3. Criticality accident alarm system

    International Nuclear Information System (INIS)

    Malenfant, R.E.

    1991-01-01

    The American National Standard ANSI/ANS-8.3-1986, Criticality Accident Alarm System provides guidance for the establishment and maintenance of an alarm system to initiate personnel evacuation in the event of inadvertent criticality. In addition to identifying the physical features of the components of the system, the characteristics of accidents of concern are carefully delineated. Unfortunately, this ANSI Standard has led to considerable confusion in interpretation, and there is evidence that the ''minimum accident of concern'' may not be appropriate. Furthermore, although intended as a guide, the provisions of the standard are being rigorously applied, sometimes with interpretations that are not consistent. Although the standard is clear in the use of absorbed dose in free air of 20 rad, at least one installation has interpreted the requirement to apply to dose in soft tissue. The standard is also clear in specifying the response to both neutrons and gamma rays. An assembly of uranyl fluoride enriched to 5% 235 U was operated to simulate a potential accident. The dose, delivered in a free run excursion 2 m from the surface of the vessel, was greater than 500 rad, without ever exceeding a rate of 20 rad/min, which is the set point for activating an alarm that meets the standard. The presence of an alarm system would not have prevented any of the five major accidents in chemical operations nor is it absolutely certain that the alarms were solely responsible for reducing personnel exposures following the accident. Nevertheless, criticality alarm systems are now the subject of great effort and expense. 13 refs

  4. Preliminary Design of Critical Function Monitoring System of PGSFR

    International Nuclear Information System (INIS)

    2015-01-01

    A PGSFR (Prototype Gen-IV Sodium-cooled Fast Reactor) is under development at Korea Atomic Energy Research Institute. A critical function monitoring system of the PGSFR is preliminarily studied. The functions of CFMS are to display critical plant variables related to the safety of the plant during normal and accident conditions and guide the operators corrective actions to keep the plant in a safe condition and mitigate the consequences of accidents. The minimal critical functions of the PGSFR are composed of reactivity control, reactor core cooling, reactor coolant system integrity, primary heat transfer system(PHTS) heat removal, sodium water reaction mitigation, radiation control and containment conditions. The variables and alarm legs of each critical function of the PGSFR are as follows; - Reactivity control: The variables of reactivity control function are power range neutron flux instrumentation, intermediate range neutron flux instrumentation, source range neutron flux instrumentation, and control rod bottom contacts. The alarm leg to display the reactivity controls consists of status of control drop malfunction, high post trip power and thermal reactivity addition. - Reactor core cooling: The variables are PHTS sodium level, hot pool temperature of PHTS, subassembly exit temperature, cold pool temperature of the PHTS, PHTS pump current, and PHTS pump breaker status. The alarm leg consists of high core delta temperature, low sodium level of the PHTS, high subassembly exit temperature, and low PHTS pump load. - Reactor coolant system integrity: The variables are PHTS sodium level, cover gas pressure, and safeguard vessel sodium level. The alarm leg is composed of low sodium level of PHTS, high cover gas pressure and high sodium level of the safety guard vessel. - PHTS heat removal: The variables are PHTS sodium level, hot pool temperature of PHTS, core exit temperature, cold pool temperature of the PHTS, flow rate of passive residual heat removal system

  5. Preliminary Design of Critical Function Monitoring System of PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-07-01

    A PGSFR (Prototype Gen-IV Sodium-cooled Fast Reactor) is under development at Korea Atomic Energy Research Institute. A critical function monitoring system of the PGSFR is preliminarily studied. The functions of CFMS are to display critical plant variables related to the safety of the plant during normal and accident conditions and guide the operators corrective actions to keep the plant in a safe condition and mitigate the consequences of accidents. The minimal critical functions of the PGSFR are composed of reactivity control, reactor core cooling, reactor coolant system integrity, primary heat transfer system(PHTS) heat removal, sodium water reaction mitigation, radiation control and containment conditions. The variables and alarm legs of each critical function of the PGSFR are as follows; - Reactivity control: The variables of reactivity control function are power range neutron flux instrumentation, intermediate range neutron flux instrumentation, source range neutron flux instrumentation, and control rod bottom contacts. The alarm leg to display the reactivity controls consists of status of control drop malfunction, high post trip power and thermal reactivity addition. - Reactor core cooling: The variables are PHTS sodium level, hot pool temperature of PHTS, subassembly exit temperature, cold pool temperature of the PHTS, PHTS pump current, and PHTS pump breaker status. The alarm leg consists of high core delta temperature, low sodium level of the PHTS, high subassembly exit temperature, and low PHTS pump load. - Reactor coolant system integrity: The variables are PHTS sodium level, cover gas pressure, and safeguard vessel sodium level. The alarm leg is composed of low sodium level of PHTS, high cover gas pressure and high sodium level of the safety guard vessel. - PHTS heat removal: The variables are PHTS sodium level, hot pool temperature of PHTS, core exit temperature, cold pool temperature of the PHTS, flow rate of passive residual heat removal system

  6. Small angle neutron scattering study of nano sized microstructure in Fe-Cr ODS steels for gen IV in-core applications.

    Science.gov (United States)

    Han, Young-Soo; Mao, Xiadong; Jang, Jinsung

    2013-11-01

    The nano-sized microstructures in Fe-Cr oxide dispersion strengthened steel for Gen IV in-core applications were studied using small angle neutron scattering. The oxide dispersion strengthened steel was manufactured through hot isostatic pressing with various chemical compositions and fabrication conditions. Small angle neutron scattering experiments were performed using a 40 m small angle neutron scattering instrument at HANARO. Nano sized microstructures, namely, yttrium oxides and Cr-oxides were quantitatively analyzed by small angle neutron scattering. The yttrium oxides and Cr-oxides were also observed by transmission electron microscopy. The microstructural analysis results from small angle neutron scattering were compared with those obtained by transmission electron microscopy. The effects of the chemical compositions and fabrication conditions on the microstructure were investigated in relation to the quantitative microstructural analysis results obtained by small angle neutron scattering. The volume fraction of Y-oxide increases after fabrication, and this result is considered to be due to the formation of non-stochiometric Y-Ti-oxides.

  7. A Qualitative Assessment Of Diversion Scenarios For A Example Sodium Fast Reactor Using The Gen IV PR And PP Methodology

    International Nuclear Information System (INIS)

    Zentner, Michael D.

    2008-01-01

    A working group was created in 2002 by the Generation IV International Forum (GIF) for the purpose of developing an internationally accepted methodology for assessing the Proliferation Resistance of a nuclear energy system (NES) and its individual elements. A two year case study is being performed by the experts group using this methodology to assess the proliferation resistance of a hypothetical NES called the Example Sodium Fast Reactor (ESFR). This work demonstrates how the PR and PP methodology can be used to provide important information at various levels of details to NES designers, safeguard administrators and decision makers. The study analyzes the response of the complete ESFR nuclear energy system to different proliferation and theft strategies. The challenges considered include concealed diversion, concealed misuse and 'break out' strategies. This paper describes the work done in performing a qualitative assessment of concealed diversion scenarios from the ESFR.

  8. A Qualitative Assessment of Diversion Scenarios for an Example Sodium Fast Reactor Using the GEN IV PR and PP Methodology

    International Nuclear Information System (INIS)

    Zentner, Michael D.; Coles, Garill A.; Therios, Ike

    2012-01-01

    FAST REACTORS;NUCLEAR ENERGY;NUCLEAR MATERIALS MANAGEMENT;PROLIFERATION;SAFEGUARDS;THEFT; A working group was created in 2002 by the Generation IV International Forum (GIF) for the purpose of developing an internationally accepted methodology for assessing the Proliferation Resistance of a nuclear energy system (NES) and its individual elements. A two year case study is being performed by the experts group using this methodology to assess the proliferation resistance of a hypothetical NES called the Example Sodium Fast Reactor (ESFR). This work demonstrates how the PR and PP methodology can be used to provide important information at various levels of details to NES designers, safeguard administrators and decision makers. The study analyzes the response of the complete ESFR nuclear energy system to different proliferation and theft strategies. The challenges considered include concealed diversion, concealed misuse and 'break out' strategies. This paper describes the work done in performing a qualitative assessment of concealed diversion scenarios from the ESFR.

  9. Multi-scale approach to the modeling of fission gas discharge during hypothetical loss-of-flow accident in gen-IV sodium fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Behafarid, F.; Shaver, D. R. [Rensselaer Polytechnic Inst., Troy, NY (United States); Bolotnov, I. A. [North Carolina State Univ., Raleigh, NC (United States); Jansen, K. E. [Univ. of Colorado, Boulder, CO (United States); Antal, S. P.; Podowski, M. Z. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2012-07-01

    The required technological and safety standards for future Gen IV Reactors can only be achieved if advanced simulation capabilities become available, which combine high performance computing with the necessary level of modeling detail and high accuracy of predictions. The purpose of this paper is to present new results of multi-scale three-dimensional (3D) simulations of the inter-related phenomena, which occur as a result of fuel element heat-up and cladding failure, including the injection of a jet of gaseous fission products into a partially blocked Sodium Fast Reactor (SFR) coolant channel, and gas/molten sodium transport along the coolant channels. The computational approach to the analysis of the overall accident scenario is based on using two different inter-communicating computational multiphase fluid dynamics (CMFD) codes: a CFD code, PHASTA, and a RANS code, NPHASE-CMFD. Using the geometry and time history of cladding failure and the gas injection rate, direct numerical simulations (DNS), combined with the Level Set method, of two-phase turbulent flow have been performed by the PHASTA code. The model allows one to track the evolution of gas/liquid interfaces at a centimeter scale. The simulated phenomena include the formation and breakup of the jet of fission products injected into the liquid sodium coolant. The PHASTA outflow has been averaged over time to obtain mean phasic velocities and volumetric concentrations, as well as the liquid turbulent kinetic energy and turbulence dissipation rate, all of which have served as the input to the core-scale simulations using the NPHASE-CMFD code. A sliding window time averaging has been used to capture mean flow parameters for transient cases. The results presented in the paper include testing and validation of the proposed models, as well the predictions of fission-gas/liquid-sodium transport along a multi-rod fuel assembly of SFR during a partial loss-of-flow accident. (authors)

  10. ASTRID, the SFR Gen IV technology demonstrator project: where are we, where do we stand for? - 15439

    International Nuclear Information System (INIS)

    Rouault, J.; Abonneau, E.; Settimo, D.; Hamy, J.M.; Hayafune, H.; Gefflot, R.; Benard, R.P.; Mandement, O.; Chauveau, T.; Lambert, G.; Audouin, P.; Mochida, H.; Iitsuka, T.; Fukuie, M; Molyneux, J.; Mazel, J.L.

    2015-01-01

    The Preconceptual Design phase (AVP1) of the ASTRID Project ended late 2012, the main goal was to evaluate innovative options. It is now followed by the AVP2 phase planned until the end of 2015 whose objectives are both to focus the design in order to finalize a coherent reactor outline and to finalize by December 2015 the Safety Option Report. The CEA acts as the industrial architect of the project. In 2014, twelve industrial partners were involved in the project. Japan which participates now in the design studies and also in Research/Development in support of the ASTRID Project and VELAN of the French 'Pole Nucleaire de Bourgogne', are the latest partners to join the Project. The Option Selection Process (RCO) is continuing during the AVP2 phase although structuring decisions remain to be made (the choice of the Energy Conversion System between Rankine cycle and Gas Brayton cycle). Other important option selections, which could nevertheless be reconsidered before starting the core of the Basic Design phase are: the choice of an internal fuel storage and a gas fuel handling chain, a rectangular reactor building with a single wall containment, the steam generator size the vertical handling of components. In addition, BOP studies considering the Marcoule site as a possible one are going on. The next important milestone is at the end of 2015 with the release by the Project team of a convincing and coherent Conceptual Design file. (authors)

  11. New RELAP5-3D Lead and LBE Thermophysical Properties Implementation for Safety Analysis of Gen IV Reactors

    Directory of Open Access Journals (Sweden)

    P. Balestra

    2016-01-01

    Full Text Available The latest versions of RELAP5-3D© code allow the simulation of thermodynamic system, using different type of working fluids, that is, liquid metals, molten salt, diathermic oil, and so forth, thanks to the ATHENA code integration. The RELAP5-3D© water thermophysical properties are largely verified and validated; however there are not so many experiments to generate the liquid metals ones in particular for the Lead and the Lead Bismuth Eutectic. Recently, new and more accurate experimental data are available for liquid metals. The comparison between these state-of-the-art data and the RELAP5-3D© default thermophysical properties shows some discrepancy; therefore a tool for the generation of new properties binary files has been developed. All the available data came from experiments performed at atmospheric pressure. Therefore, to extend the pressure domain below and above this pressure, the tool fits a semiempirical model (soft sphere model with inverse-power-law potential, specific for the liquid metals. New binary files of thermophysical properties, with a detailed mesh grid of point to reduce the code mass error (especially for the Lead, were generated with this tool. Finally, calculations using a simple natural circulation loop were performed to understand the differences between the default and the new properties.

  12. Critical points in magnetic systems

    International Nuclear Information System (INIS)

    Bongaarts, A.L.M.

    1975-01-01

    The magnetical phase transitions of CsCoCl 3 .2H 2 O and CsCoCl 3 .2D 2 O are investigated by neutron diffraction techniques with special attention to the critical points in the phase diagrams. CsCoCl 3 .2H 2 O turned out to be a one-dimentional magnetic antiferromagnet with ferromagnetic and antiferromagnetic interactions. In the vicinity of the Neel point, the critical behavior in zero magnetic field could be described as a three-dimentional long range ordering, while the fluctuations in the system are one-dimensional. In the presence of a magnetic field, the behavior of the system in the critical region of the magnetic phase diagram between the Neel temperature at zero field (3.3degK) and 1.85degK, was in good agreement with the theory. Below 1.85degK, the phase transition in a magnetic field changes into a line of triple points whose end point could be identified as a tricritical point, i.e., an intersection of three critical lines. The parameters derived from observations in the neighborhood of this tricritical point obey the scaling laws but are not in numerical agreement with theoretical predictions

  13. 75 FR 11918 - Hewlett Pachard Company, Business Critical Systems, Mission Critical Business Software Division...

    Science.gov (United States)

    2010-03-12

    ... Pachard Company, Business Critical Systems, Mission Critical Business Software Division, Openvms Operating... Colorado, Marlborough, Massachuetts; Hewlett Pachard Company, Business Critical Systems, Mission Critical... Company, Business Critical Systems, Mission Critical Business Software Division, OpenVMS Operating System...

  14. Outsourcing critical financial system operations.

    Science.gov (United States)

    Cox, Nora; Pilbauer, Jan

    2018-01-01

    Payments Canada provides Canada's national payments systems and is responsible for the clearing and settlement infrastructure, processes and rules that underpin the exchange of billions of dollars each day through the Canadian economy. Strategic sourcing is a reality for this small organisation with a broad scope of national regulations and global standards to comply with. This paper outlines Payments Canada's approach to outsourcing its critical financial system operations, which centres on four key principles: strong relationship management; continuous learning, recording and reporting; evaluating the business landscape; and a commitment to evolving the organisation to greater resilience. This last point is covered in detail with an exploration of the organisation's resilience and security strategy as well as its risk appetite. As Payments Canada progresses to its future state, which includes modernising its core payment systems, underlying rules and standards, risk management for the industry as a whole will remain at the forefront of its collective mind. The expectation is that outsourcing will remain a fundamental element of its operating model in future, a strategy that will ensure the organisation can focus on its core business competencies and eliminate the need to develop and support in-house expertise in commodity areas.

  15. Critical function monitoring system algorithm development

    International Nuclear Information System (INIS)

    Harmon, D.L.

    1984-01-01

    Accurate critical function status information is a key to operator decision-making during events threatening nuclear power plant safety. The Critical Function Monitoring System provides continuous critical function status monitoring by use of algorithms which mathematically represent the processes by which an operating staff would determine critical function status. This paper discusses in detail the systematic design methodology employed to develop adequate Critical Function Monitoring System algorithms

  16. Design and development of self-powered sensors on wireless sensor network for standalone plant critical data management during SBO and beyond design basis events

    International Nuclear Information System (INIS)

    Aparna, J.; Dulera, I.V.; Rama Rao, A.; Vijayan, P.K.

    2015-01-01

    Advanced reactors are designed with an aim of maximum safety, optimized fuel utilization and effective system design. Safety aspects in reactor designs are being viewed for all possible vulnerabilities, and as a result, robust self-regulating passive safety features have been favored in Gen IV and advanced reactor designs. In addition to passive systems, the accidents scenarios at Fukushima indicate the dire need of reliable and stand-alone self-powered sensors, for monitoring plant critical parameters for effective damage control actions. There is a strong need for plant critical data management and situation awareness during the unavailability of all conventional power sources in a nuclear power plant, during extended station blackout (SBO) conditions. These self-powered sensors would assist the operators in managing events like SBO and help in containing any Beyond Design Basis Events (BDBE) conditions, well away from the public domain

  17. From a LWR monoculture to a synergistic use of nuclear systems. Introducing a new way of looking at GEN-IV economics

    International Nuclear Information System (INIS)

    Laeuferts, U.; Heek, A. van; Anderluh, J.

    2009-01-01

    The authors discuss the value that fast reactor technologies add to the current LWR design by hedging against uncertainties in the front-end and back-end of the fuel cycle. Using Monte Carlo simulation for these underlying uncertainties in fuel cycle costs the authors found in a first explorative attempt an approximation for the real option value. The model oversimplifies the demand/supply site of the fuel cycle services and is not exhaustive concerning all fuel cycle options, but gives first impression over the benefits of introducing real option thinking.Future work could give a good indication about the thresholds of fuel cycle services and transaction costs, including the development and timing of additional reprocessing and fuel fabrication plants.

  18. Critical enrichment and critical density of infinite systems for nuclear criticality safety evaluation

    International Nuclear Information System (INIS)

    Naito, Yoshitaka; Koyama, Takashi; Komuro, Yuichi

    1986-03-01

    Critical enrichment and critical density of homogenous infinite systems, such as U-H 2 O, UO 2 -H 2 O, UO 2 F 2 aqueous solution, UO 2 (NO 3 ) 2 aqueous solution, Pu-H 2 O, PuO 2 -H 2 O, Pu(NO 3 ) 4 aqueous solution and PuO 2 ·UO 2 -H 2 O, were calculated with the criticality safety evaluation computer code system JACS for nuclear criticality safety evaluation on fuel facilities. The computed results were compared with the data described in European and American criticality handbooks and showed good agreement with each other. (author)

  19. Systems pathology: a critical review.

    Science.gov (United States)

    Costa, Jose

    2012-02-01

    The technological advances of the last twenty years together with the dramatic increase in computational power have injected new life into systems-level thinking in Medicine. This review emphasizes the close relationship of Systems Pathology to Systems Biology and delineates the differences between Systems Pathology and Clinical Systems Pathology. It also suggests an algorithm to support the application of systems-level thinking to clinical research, proposes applying systems-level thinking to the health care systems and forecasts an acceleration of preventive medicine as a result of the coupling of personal genomics with systems pathology. Copyright © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  20. Condensation and homogenization of cross sections for the deterministic transport codes with Monte Carlo method: Application to the GEN IV fast neutron reactors

    International Nuclear Information System (INIS)

    Cai, Li

    2014-01-01

    In the framework of the Generation IV reactors neutronic research, new core calculation tools are implemented in the code system APOLLO3 for the deterministic part. These calculation methods are based on the discretization concept of nuclear energy data (named multi-group and are generally produced by deterministic codes) and should be validated and qualified with respect to some Monte-Carlo reference calculations. This thesis aims to develop an alternative technique of producing multi-group nuclear properties by a Monte-Carlo code (TRIPOLI-4). At first, after having tested the existing homogenization and condensation functionalities with better precision obtained nowadays, some inconsistencies are revealed. Several new multi-group parameters estimators are developed and validated for TRIPOLI-4 code with the aid of itself, since it has the possibility to use the multi-group constants in a core calculation. Secondly, the scattering anisotropy effect which is necessary for handling neutron leakage case is studied. A correction technique concerning the diagonal line of the first order moment of the scattering matrix is proposed. This is named the IGSC technique and is based on the usage of an approximate current which is introduced by Todorova. An improvement of this IGSC technique is then presented for the geometries which hold an important heterogeneity property. This improvement uses a more accurate current quantity which is the projection on the abscissa X. The later current can represent the real situation better but is limited to 1D geometries. Finally, a B1 leakage model is implemented in the TRIPOLI-4 code for generating multi-group cross sections with a fundamental mode based critical spectrum. This leakage model is analyzed and validated rigorously by the comparison with other codes: Serpent and ECCO, as well as an analytical case.The whole development work introduced in TRIPOLI-4 code allows producing multi-group constants which can then be used in the core

  1. Intelligent Transportation Systems : critical standards

    Science.gov (United States)

    1999-06-01

    Intelligent Transportation Systems (ITS) standards are industry-consensus standards that provide the details about how different systems interconnect and communicate information to deliver the ITS user services described in the National ITS Architect...

  2. Achieving Critical System Survivability Through Software Architectures

    National Research Council Canada - National Science Library

    Knight, John C; Strunk, Elisabeth A

    2006-01-01

    .... In a system with a survivability architecture, under adverse conditions such as system damage or software failures, some desirable function will be eliminated but critical services will be retained...

  3. Critical infrastructure systems of systems assessment methodology.

    Energy Technology Data Exchange (ETDEWEB)

    Sholander, Peter E.; Darby, John L.; Phelan, James M.; Smith, Bryan; Wyss, Gregory Dane; Walter, Andrew; Varnado, G. Bruce; Depoy, Jennifer Mae

    2006-10-01

    Assessing the risk of malevolent attacks against large-scale critical infrastructures requires modifications to existing methodologies that separately consider physical security and cyber security. This research has developed a risk assessment methodology that explicitly accounts for both physical and cyber security, while preserving the traditional security paradigm of detect, delay, and respond. This methodology also accounts for the condition that a facility may be able to recover from or mitigate the impact of a successful attack before serious consequences occur. The methodology uses evidence-based techniques (which are a generalization of probability theory) to evaluate the security posture of the cyber protection systems. Cyber threats are compared against cyber security posture using a category-based approach nested within a path-based analysis to determine the most vulnerable cyber attack path. The methodology summarizes the impact of a blended cyber/physical adversary attack in a conditional risk estimate where the consequence term is scaled by a ''willingness to pay'' avoidance approach.

  4. Safety-critical Java for embedded systems

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Dalsgaard, Andreas Engelbredt; Hansen, René Rydhof

    2016-01-01

    This paper presents the motivation for and outcomes of an engineering research project on certifiable Javafor embedded systems. The project supports the upcoming standard for safety-critical Java, which defines asubset of Java and libraries aiming for development of high criticality systems....... The outcome of this projectinclude prototype safety-critical Java implementations, a time-predictable Java processor, analysis tools formemory safety, and example applications to explore the usability of safety-critical Java for this applicationarea. The text summarizes developments and key contributions...

  5. NCIS: a nuclear criticality information system

    International Nuclear Information System (INIS)

    Koponen, B.L.; Hampel, V.E.

    1984-01-01

    The NCIS is one of the developments carried out to meet the requirements in the field of criticality safety information. Its primary goal is to enhance nuclear criticality safety by dissemination of data, standards, and training material. This paper presents the ''NCIS'' progess since 1950: computer-searching, database management, nuclear critical experiments bibliography. American Nuclear Society transactions criticality safety publications compilation, edition of a personnel directory representing over 140 organizations located in 16 countries and showing a wide range of specialists involved in the field of nuclear criticality safety. The NCIS uses the information management and communication resources of TIS (Technology Information System): automated access procedures; creation of program-dependent information systems; communications. The NCIS is still in a growing, formative stage; it has concentrated first on collecting and organizing the nuclear criticality literature; nuclear critical data, calculational tools, standards, and training materials will follow. Finally the planned and contemplated resources are dealt with: expansion of bibliographic compilations; news database; fundamental criticality safety reference; criticality benchmarck database; user community; training resources; related resources; criticality accident database; dynamic databook; dynamic textbook; expert knowledge system; and, extraction of intelligence

  6. Mission-Critical Systems Design Framework

    Directory of Open Access Journals (Sweden)

    Kyriakos Houliotis

    2018-03-01

    Full Text Available Safety-critical systems are well documented and standardized (e.g. IEC 61508, RTCA DO-178B within system design cycles. However in Defence and Security, systems that are critical to the success of a Mission are not defined within the literature nor are there any guidelines in defining criticality in their design or operational capabilities. When it comes to Vetronics (Vehicle Electronics, a mission-critical system, is a system with much complexity and mixed criticality levels that is a part of the overall platform (military vehicle offering integrated system capabilities. In this paper, a framework is presented, providing guidelines in designing efficiently and effectively mission-critical systems considering principles of Interoperable Open Architectures (IOA, mission-critical integrity levels and following new standardization activities such as NATO Generic Vehicle Architecture (NGVA. A Defensive Aid Suite (DAS system is used as a case study to illustrate how this framework can be exploited. The indention of this extension is to provide an approach to precisely estimate threats in order to de-risk missions in the very early stages.

  7. Criticality and entanglement in random quantum systems

    International Nuclear Information System (INIS)

    Refael, G; Moore, J E

    2009-01-01

    We review studies of entanglement entropy in systems with quenched randomness, concentrating on universal behavior at strongly random quantum critical points. The disorder-averaged entanglement entropy provides insight into the quantum criticality of these systems and an understanding of their relationship to non-random ('pure') quantum criticality. The entanglement near many such critical points in one dimension shows a logarithmic divergence in subsystem size, similar to that in the pure case but with a different universal coefficient. Such universal coefficients are examples of universal critical amplitudes in a random system. Possible measurements are reviewed along with the one-particle entanglement scaling at certain Anderson localization transitions. We also comment briefly on higher dimensions and challenges for the future.

  8. Validation Of Critical Knowledge-Based Systems

    Science.gov (United States)

    Duke, Eugene L.

    1992-01-01

    Report discusses approach to verification and validation of knowledge-based systems. Also known as "expert systems". Concerned mainly with development of methodologies for verification of knowledge-based systems critical to flight-research systems; e.g., fault-tolerant control systems for advanced aircraft. Subject matter also has relevance to knowledge-based systems controlling medical life-support equipment or commuter railroad systems.

  9. NCIS - a Nuclear Criticality Information System (overview)

    International Nuclear Information System (INIS)

    Koponen, B.L.; Hampel, V.E.

    1983-07-01

    A Nuclear Criticality Information System (NCIS) is being established at the Lawrence Livermore National Laboratory (LLNL) in order to serve personnel responsible for safe storage, transport, and handling of fissile materials and those concerned with the evaluation and analysis of nuclear, critical experiments. Public concern for nuclear safety provides the incentive for improved access to nuclear safety information

  10. Critical Thresholds in Earth-System Dynamics

    Science.gov (United States)

    Rothman, D.

    2017-12-01

    The history of the Earth system is a story of change. Some changesare gradual and benign, but others, especially those associated withcatastrophic mass extinction, are relatively abrupt and destructive.What sets one group apart from the other? Here I hypothesize thatperturbations of Earth's carbon cycle lead to mass extinction if theyexceed either a critical rate at long time scales or a critical sizeat short time scales. By analyzing 31 carbon-isotopic events duringthe last 542 million years, I identify the critical rate with a limitimposed by mass conservation. Further analysis identifies thecrossover timescale separating fast from slow events with thetimescale of the ocean's homeostatic response to a change in pH. Theproduct of the critical rate and the crossover timescale then yieldsthe critical size. The modern critical size for the marine carboncycle is roughly similar to the mass of carbon that human activitieswill likely have added to the oceans by the year 2100.

  11. System Predicts Critical Runway Performance Parameters

    Science.gov (United States)

    Millen, Ernest W.; Person, Lee H., Jr.

    1990-01-01

    Runway-navigation-monitor (RNM) and critical-distances-process electronic equipment designed to provide pilot with timely and reliable predictive navigation information relating to takeoff, landing and runway-turnoff operations. Enables pilot to make critical decisions about runway maneuvers with high confidence during emergencies. Utilizes ground-referenced position data only to drive purely navigational monitor system independent of statuses of systems in aircraft.

  12. Technical guide to criticality alarm system design

    International Nuclear Information System (INIS)

    Greenfield, B.

    2009-01-01

    An instructional manual was created to guide criticality safety engineers through the technical aspects of designing a criticality alarm system (CAS) for Dept. of Energy (DOE) hazard class 1 and 2 facilities. The manual was structured such that it can be used by engineers designing completely new systems and by those who are working with existing facilities. Major design tasks are thoroughly analyzed to provide concise direction for how to complete the analysis. Regulatory and technical performance requirements were both addressed. (authors)

  13. Critical infrastructure system security and resiliency

    CERN Document Server

    Biringer, Betty; Warren, Drake

    2013-01-01

    Security protections for critical infrastructure nodes are intended to minimize the risks resulting from an initiating event, whether it is an intentional malevolent act or a natural hazard. With an emphasis on protecting an infrastructure's ability to perform its mission or function, Critical Infrastructure System Security and Resiliency presents a practical methodology for developing an effective protection system that can either prevent undesired events or mitigate the consequences of such events.Developed at Sandia National Labs, the authors' analytical approach and

  14. Critical Points in Distance Learning System

    Directory of Open Access Journals (Sweden)

    Airina Savickaitė

    2013-08-01

    Full Text Available Purpose – This article presents the results of distance learning system analysis, i.e. the critical elements of the distance learning system. The critical points of distance learning are a part of distance education online environment interactivity/community process model. The most important is the fact that the critical point is associated with distance learning participants. Design/methodology/approach – Comparative review of articles and analysis of distance learning module. Findings – A modern man is a lifelong learner and distance learning is a way to be a modern person. The focus on a learner and feedback is the most important thing of learning distance system. Also, attention should be paid to the lecture-appropriate knowledge and ability to convey information. Distance system adaptation is the way to improve the learner’s learning outcomes. Research limitations/implications – Different learning disciplines and learning methods may have different critical points. Practical implications – The information of analysis could be important for both lecturers and students, who studies distance education systems. There are familiar critical points which may deteriorate the quality of learning. Originality/value – The study sought to develop remote systems for applications in order to improve the quality of knowledge. Keywords: distance learning, process model, critical points. Research type: review of literature and general overview.

  15. Critical Incident Reporting Systems: Perceived Competing Social ...

    African Journals Online (AJOL)

    The safe operation of complex socio-technical systems is dependent upon the reporting of safety critical incidents by operators within a system. Through the action of reporting, systems develop the capability as a learning organisation to improve human and organisational performance. The aim of the study is therefore to ...

  16. The Nuclear Criticality Information System: An update

    International Nuclear Information System (INIS)

    Koponen, B.L.

    1991-07-01

    The US Department of Energy's Nuclear Criticality Information System (NCIS) has served the criticality community for the past ten years with publications and with an online information system. NCIS provides a mean for widely distributed nuclear criticality specialists to communicate and work together instantly. Users of the system may receive assistance from all members of the NCIS community, which provides a much broader base of support than is available at any single site. When unified by NCIS, these diverse specialists provide a resource that has proven to be very useful in the safe handling of fissile material. NCIS also is a source of current nuclear criticality safety information; the rapid access of such up-to-date information on the handling of fissile materials outside of nuclear reactors is international in scope, extending beyond political and geographical boundaries

  17. Regulatory Safety Issues in the Structural Design Criteria of ASME Section III Subsection NH and for Very High Temperatures for VHTR and GEN IV

    International Nuclear Information System (INIS)

    O'Donnell, William J.; Griffin, Donald S.

    2007-01-01

    The objective of this task is to identify issues relevant to ASME Section III, Subsection NH [1], and related Code Cases that must be resolved for licensing purposes for VHTGRs (Very High Temperature Gas Reactor concepts such as those of PBMR, Areva, and GA); and to identify the material models, design criteria, and analysis methods that need to be added to the ASME Code to cover the unresolved safety issues. Subsection NH was originally developed to provide structural design criteria and limits for elevated-temperature design of Liquid Metal Fast Breeder Reactor (LMFBR) systems and some gas-cooled systems. The U.S. Nuclear Regulatory Commission (NRC) and its Advisory Committee for Reactor Safeguards (ACRS) reviewed the design limits and procedures in the process of reviewing the Clinch River Breeder Reactor (CRBR) for a construction permit in the late 1970s and early 1980s, and identified issues that needed resolution. In the years since then, the NRC and various contractors have evaluated the applicability of the ASME Code and Code Cases to high-temperature reactor designs such as the VHTGRs, and identified issues that need to be resolved to provide a regulatory basis for licensing. This Report describes: (1) NRC and ACRS safety concerns raised during the licensing process of CRBR , (2) how some of these issues are addressed by the current Subsection NH of the ASME Code; and (3) the material models, design criteria, and analysis methods that need to be added to the ASME Code and Code Cases to cover unresolved regulatory issues for very high temperature service.

  18. Regulatory Safety Issues in the Structural Design Criteria of ASME Section III Subsection NH and for Very High Temperatures for VHTR & GEN IV

    Energy Technology Data Exchange (ETDEWEB)

    William J. O’Donnell; Donald S. Griffin

    2007-05-07

    The objective of this task is to identify issues relevant to ASME Section III, Subsection NH [1], and related Code Cases that must be resolved for licensing purposes for VHTGRs (Very High Temperature Gas Reactor concepts such as those of PBMR, Areva, and GA); and to identify the material models, design criteria, and analysis methods that need to be added to the ASME Code to cover the unresolved safety issues. Subsection NH was originally developed to provide structural design criteria and limits for elevated-temperature design of Liquid Metal Fast Breeder Reactor (LMFBR) systems and some gas-cooled systems. The U.S. Nuclear Regulatory Commission (NRC) and its Advisory Committee for Reactor Safeguards (ACRS) reviewed the design limits and procedures in the process of reviewing the Clinch River Breeder Reactor (CRBR) for a construction permit in the late 1970s and early 1980s, and identified issues that needed resolution. In the years since then, the NRC and various contractors have evaluated the applicability of the ASME Code and Code Cases to high-temperature reactor designs such as the VHTGRs, and identified issues that need to be resolved to provide a regulatory basis for licensing. This Report describes: (1) NRC and ACRS safety concerns raised during the licensing process of CRBR , (2) how some of these issues are addressed by the current Subsection NH of the ASME Code; and (3) the material models, design criteria, and analysis methods that need to be added to the ASME Code and Code Cases to cover unresolved regulatory issues for very high temperature service.

  19. Critical care nursing: Embedded complex systems.

    Science.gov (United States)

    Trinier, Ruth; Liske, Lori; Nenadovic, Vera

    2016-01-01

    Variability in parameters such as heart rate, respiratory rate and blood pressure defines healthy physiology and the ability of the person to adequately respond to stressors. Critically ill patients have lost this variability and require highly specialized nursing care to support life and monitor changes in condition. The critical care environment is a dynamic system through which information flows. The critical care unit is typically designed as a tree structure with generally one attending physician and multiple nurses and allied health care professionals. Information flow through the system allows for identification of deteriorating patient status and timely interventionfor rescue from further deleterious effects. Nurses provide the majority of direct patient care in the critical care setting in 2:1, 1:1 or 1:2 nurse-to-patient ratios. The bedside nurse-critically ill patient relationship represents the primary, real-time feedback loop of information exchange, monitoring and treatment. Variables that enhance information flow through this loop and support timely nursing intervention can improve patient outcomes, while barriers can lead to errors and adverse events. Examining patient information flow in the critical care environment from a dynamic systems perspective provides insights into how nurses deliver effective patient care and prevent adverse events.

  20. 75 FR 5146 - Hewlett Packard Company Business Critical Systems, Mission Critical Business Software Division...

    Science.gov (United States)

    2010-02-01

    ... Packard Company Business Critical Systems, Mission Critical Business Software Division, OpenVMS Operating... Colorado, Marlborough, MA; Hewlett Packard Company Business Critical Systems, Mission Critical Business... Assistance on August 27, 2009, applicable to workers of Hewlett Packard Company, Business Critical Systems...

  1. Critically Important Object Security System Element Model

    Directory of Open Access Journals (Sweden)

    I. V. Khomyackov

    2012-03-01

    Full Text Available A stochastic model of critically important object security system element has been developed. The model includes mathematical description of the security system element properties and external influences. The state evolution of the security system element is described by the semi-Markov process with finite states number, the semi-Markov matrix and the initial semi-Markov process states probabilities distribution. External influences are set with the intensity of the Poisson thread.

  2. DEVELOPMENT OF RISK-BASED AND TECHNOLOGY-INDEPENDENT SAFETY CRITERIA FOR GENERATION IV SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    William E. Kastenberg; Edward Blandford; Lance Kim

    2009-03-31

    This project has developed quantitative safety goals for Generation IV (Gen IV) nuclear energy systems. These safety goals are risk based and technology independent. The foundations for a new approach to risk analysis has been developed, along with a new operational definition of risk. This project has furthered the current state-of-the-art by developing quantitative safety goals for both Gen IV reactors and for the overall Gen IV nuclear fuel cycle. The risk analysis approach developed will quantify performance measures, characterize uncertainty, and address a more comprehensive view of safety as it relates to the overall system. Appropriate safety criteria are necessary to manage risk in a prudent and cost-effective manner. This study is also important for government agencies responsible for managing, reviewing, and for approving advanced reactor systems because they are charged with assuring the health and safety of the public.

  3. DEVELOPMENT OF RISK-BASED AND TECHNOLOGY-INDEPENDENT SAFETY CRITERIA FOR GENERATION IV SYSTEMS

    International Nuclear Information System (INIS)

    Kastenberg, William E.; Blandford, Edward; Kim, Lance

    2009-01-01

    This project has developed quantitative safety goals for Generation IV (Gen IV) nuclear energy systems. These safety goals are risk based and technology independent. The foundations for a new approach to risk analysis has been developed, along with a new operational definition of risk. This project has furthered the current state-of-the-art by developing quantitative safety goals for both Gen IV reactors and for the overall Gen IV nuclear fuel cycle. The risk analysis approach developed will quantify performance measures, characterize uncertainty, and address a more comprehensive view of safety as it relates to the overall system. Appropriate safety criteria are necessary to manage risk in a prudent and cost-effective manner. This study is also important for government agencies responsible for managing, reviewing, and for approving advanced reactor systems because they are charged with assuring the health and safety of the public

  4. Building competencies for New Gen IV Reactors

    International Nuclear Information System (INIS)

    Pavel, G.L.; Ghitescu, P.

    2015-01-01

    The Advanced Lead Fast Reactor European Demonstrator - ALFRED is designed and sustained by several European countries. It is a 300 MWt (125 MWe) reactor, intended to be built in Romania, near the Pitesti site. Pure lead is used as primary coolant and it is foreseen to have a 40% thermal efficiency. Secondary cycle contains superheated water steam at around 450 Celsius degrees. Through ARCADIA cooperation, 26 partners from all over Europe joined their forces to provide the necessary research support for ALFRED. In Romania, several entities are providing nuclear courses but only the University Politechnica of Bucharest is offering a complete training program for nuclear industry but targeted courses for LFR technology need to be developed and implemented. Issues like physics of breeding, coolant analysis and behavior, targeted computer codes, core design and dynamics, safety still needs to be tackled

  5. New Materials for NGNP/Gen IV

    International Nuclear Information System (INIS)

    Swindeman, Robert W.; Marriott, Douglas L.

    2009-01-01

    The bounding conditions were briefly summarized for the Next Generation Nuclear Plant (NGNP) that is the leading candidate in the Department of Energy Generation IV reactor program. Metallic materials essential to the successful development and proof of concept for the NGNP were identified. The literature bearing on the materials technology for high-temperature gas-cooled reactors was reviewed with emphasis on the needs identified for the NGNP. Several materials were identified for a more thorough study of their databases and behavioral features relative to the requirements ASME Boiler and Pressure Vessel Code, Section III, Division 1, Subsection NH.

  6. Systems biology in critical-care nursing.

    Science.gov (United States)

    Schallom, Lynn; Thimmesch, Amanda R; Pierce, Janet D

    2011-01-01

    Systems biology applies advances in technology and new fields of study including genomics, transcriptomics, proteomics, and metabolomics to the development of new treatments and approaches of care for the critically ill and injured patient. An understanding of systems biology enhances a nurse's ability to implement evidence-based practice and to educate patients and families on novel testing and therapies. Systems biology is an integrated and holistic view of humans in relationship with the environment. Biomarkers are used to measure the presence and severity of disease and are rapidly expanding in systems biology endeavors. A systems biology approach using predictive, preventive, and participatory involvement is being utilized in a plethora of conditions of critical illness and injury including sepsis, cancer, pulmonary disease, and traumatic injuries.

  7. A critical incident reporting system in anaesthesia.

    Science.gov (United States)

    Madzimbamuto, F D; Chiware, R

    2001-01-01

    To audit the recently established Critical Incident Reporting System in the Department of Anaesthesia and Critical Care Medicine, University of Zimbabwe Medical School. The system was set up with the purpose of improving the quality of care delivered by the department. Cross sectional study. A critical incident was defined as 'any adverse and reversible event in theatre, during or immediately after surgery that if it persisted without correction would cause harm to the patient'. The anaesthetic or recovery room staff filled a critical incident form anonymously. Data was collected from critical incident reporting forms for analysis. The anaesthetic service in the two teaching hospitals of Harare Central and Parirenyatwa General Hospitals. Between May and October 2000, 62 completed critical incident forms were collected. The nature of the incident and the monitoring used were recorded, the cause was classified as human, equipment or monitoring failure and the outcome for each patient reported. There was no formal system for reminding staff to fill in their critical incident forms. A total of 14,165 operations were performed over the reporting period: 62 critical incident forms were collected, reporting 130 incidents, giving a rate of 0.92% (130/14,165). Of these, 42 patients were emergencies and 20 elective. The incidents were hypotension, hypoxia, bradycardia, ECG changes, aspiration, laryngospasm, high spinal, and cardiac arrest. Monitoring present on patients who had critical incidents was: capnography 57%, oxymetry 90% and ECG 100%. Other monitors are not reported. Human error contributed in 32/62 of patients and equipment failure in 31/62 of patients. Patient outcome showed 15% died, 23% were unplanned admissions to HDU while 62% were discharged to the ward with little or no adverse outcome. Despite some under reporting, the critical incident rate was within the range reported in the literature. Supervision of juniors is not adequate, especially on call. The

  8. Transactions of the criticality alarm systems workshop

    International Nuclear Information System (INIS)

    1988-01-01

    The first Criticality Alarm workshop was held by the US Department of Energy Albuquerque Operations Office in 1985. This second workshop is the first held on an international level. There were 98 persons in attendance. They represented the Department of Energy (DOE) field offices, DOE contractors, the Nuclear Regulatory Commission (NRC), NRC licensees, and agencies in the United Kingdom, France, West Germany, and Japan. Topics were on practices experience, and development. A key value of the workshop was the sharing of critical alarm system experiences, problems, and advances in the state of the art. In addition, several Criticality Alarm Systems (CAS) equipment systems were exhibited. Papers were presented on: nature of criticality accidents; lessons learned from past accidents; application of ANS 8.3 standard; gamma and neutron detection systems; research and development in progress; testing at Oak Ridge and Los Alamos; methods used to place detectors; centralized readout feature; false alarms; trip-point settings; and testing and maintenance. The individual papers have been cataloged separately

  9. Critical Systems Thinking on Decentralization: the Corporate ...

    African Journals Online (AJOL)

    This article calls for the devolution of power by large organizations to their subsidiaries or subordinate units – mainly Strategic Business Units (SBUs). It proposes more decentralized models of management and outlines a new theory taking a critical systems thinking approach. Corporations are advised to attack and ...

  10. Critical opalescence in the pure Coulomb system

    Energy Technology Data Exchange (ETDEWEB)

    Bobrov, V.B., E-mail: vic5907@mail.r [Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaia St., 13, Bd. 2. Moscow 125412 (Russian Federation); Trigger, S.A., E-mail: satron@mail.r [Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaia St., 13, Bd. 2. Moscow 125412 (Russian Federation); Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstrasse 15, D-12489 Berlin (Germany)

    2011-04-18

    Highlights: The review of the critical opalescence problem is presented. Light scattering in a two-component electron-nuclear system is studied. The exact relations between the structure factors and compressibility are found. The obtained relations are valid for strong interaction for the Coulomb systems. The experimental verification of these relations is possible for various elements. - Abstract: Based on the dielectric formalism and quantum field theory methods, the phenomenon of critical opalescence is explained for light scattering in pure matter as a two-component electron-nuclear system with Coulomb interaction. A similar phenomenon is shown to occur in the case of neutron scattering in pure substances as well. The obtained results are valid for quantum case and arbitrary strong Coulomb interaction. Thus, the relations between structure factors derived for the electron-nuclear system are the exact result of the quantum statistical mechanics.

  11. Critical opalescence in the pure Coulomb system

    International Nuclear Information System (INIS)

    Bobrov, V.B.; Trigger, S.A.

    2011-01-01

    Highlights: → The review of the critical opalescence problem is presented. → Light scattering in a two-component electron-nuclear system is studied. → The exact relations between the structure factors and compressibility are found. → The obtained relations are valid for strong interaction for the Coulomb systems. → The experimental verification of these relations is possible for various elements. - Abstract: Based on the dielectric formalism and quantum field theory methods, the phenomenon of critical opalescence is explained for light scattering in pure matter as a two-component electron-nuclear system with Coulomb interaction. A similar phenomenon is shown to occur in the case of neutron scattering in pure substances as well. The obtained results are valid for quantum case and arbitrary strong Coulomb interaction. Thus, the relations between structure factors derived for the electron-nuclear system are the exact result of the quantum statistical mechanics.

  12. The critical care cascade: a systems approach.

    Science.gov (United States)

    Ghosh, Rishi; Pepe, Paul

    2009-08-01

    To emphasize the evolving body of evidence that supports the need for a more seamless and interconnected continuum of patient care for a growing compendium of critical care conditions, starting in the prehospital and emergency department (ED) phases of management and continuing through ICU and rehabilitation services. The care of critically ill and injured patients has become increasingly complex. It now has been demonstrated that, for a number of such critical care conditions, optimal management not only relies heavily on the talents of highly coordinated, multidisciplinary teams, but it also may require shared responsibilities across a continuum of longitudinal care involving numerous specialties and departments. This continuum usually needs to begin in the prehospital and ED settings with management extending through specialized in-hospital diagnostic and interventional suites to traditional ICU and rehabilitation programs. In recent years, examples of these conditions have included the development of systems of care for trauma, cardiac arrest, myocardial infarction, stroke, sepsis syndromes, toxicology and other critical illnesses. Although the widespread implementation of such multidisciplinary, multispecialty critical care cascades of care has been achieved most commonly in trauma care, current healthcare delivery systems generally tend to employ compartmentalized organization for the majority of other critical care patients. Accordingly, optimal systematic care often breaks down in the management of these complex patients due to barriers such as lack of interoperable communication between teams, disjointed transfers between services, unnecessary time-consuming, re-evaluations and transitional pauses in time-dependent circumstances, deficiencies in cross-disciplinary education and quality assurance loops, and significant variability in patient care practices. Such barriers can lead to adverse outcomes in this fragile patient population. This article discusses

  13. Microservices: Migration of a Mission Critical System

    OpenAIRE

    Dragoni, Nicola; Dustdar, Schahram; Larsen, Stephan T.; Mazzara, Manuel

    2017-01-01

    The microservices paradigm aims at changing the way in which software is perceived, conceived and designed. One of the foundational characteristics of this new promising paradigm, compared for instance to monolithic architectures, is scalability. In this paper, we present a real world case study in order to demonstrate how scalability is positively affected by re-implementing a monolithic architecture into microservices. The case study is based on the FX Core system, a mission critical system...

  14. Security for safety critical space borne systems

    Science.gov (United States)

    Legrand, Sue

    1987-01-01

    The Space Station contains safety critical computer software components in systems that can affect life and vital property. These components require a multilevel secure system that provides dynamic access control of the data and processes involved. A study is under way to define requirements for a security model providing access control through level B3 of the Orange Book. The model will be prototyped at NASA-Johnson Space Center.

  15. Report and analysis on 'PR and PP evaluation. Example sodium fast reactor full system case study'

    International Nuclear Information System (INIS)

    Sagara, Hiroshi; Inoue, Naoko; Kawakubo, Yoko; Watahiki, Masaru

    2011-01-01

    The Generation IV (GEN IV) Nuclear Energy Systems International Forum (GIF) Proliferation Resistance and Physical Protection Working Group (PRPP WG) was established in December 2002 in order to develop the PR and valuation methodology for GEN IV nuclear energy systems. In the final report of 'PR and PP Evaluation: Example Sodium Fast Reactor (ESFR) Full System Case Study,' issued in October 2009, the demonstration study of PR and PP evaluation with the qualitative approach are summarized using ESFR with four scenario threats. The present paper reviews and analyzes some results of the ESFR case study, and identifies the challenges and direction for the PR and PP evaluation methodology with quantitative approach. (author)

  16. Safety-Critical Java for Embedded Systems

    DEFF Research Database (Denmark)

    Rios Rivas, Juan Ricardo

    for Java aims at providing a reduced set of the Java programming language that can be used for systems that need to be certified at the highest levels of criticality. Safety-critical Java (SCJ) restricts how a developer can structure an application by providing a specific programming model...... and by restricting the set of methods and libraries that can be used. Furthermore, its memory model do not use a garbage-collected heap but scoped memories. In this thesis we examine the use of the SCJ specification through an implementation in a time-predictable, FPGA-based Java processor. The specification is now...

  17. The octopus burnup and criticality code system

    Energy Technology Data Exchange (ETDEWEB)

    Kloosterman, J.L.; Kuijper, J.C. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands); Leege, P.F.A. de

    1996-09-01

    The OCTOPUS burnup and criticality code system is described. This system links the spectrum codes from the SCALE4.1, WIMS7 and MCNP4A packages to the ORIGEN-S and FISPACT4.2 fuel depletion and activation codes, which enables us to perform very accurate burnup calculations in complicated three-dimensional geometries. The data used by all codes are consistently based on the JEF2.2 evaluated nuclear data file. Some special features of OCTOPUS not available in other codes are described, as well as the validation of the system. (author)

  18. The OCTOPUS burnup and criticality code system

    Energy Technology Data Exchange (ETDEWEB)

    Kloosterman, J.L. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands); Kuijper, J.C. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands); Leege, P.F.A. de [Technische Univ. Delft (Netherlands). Interfacultair Reactor Inst.

    1996-06-01

    The OCTOPUS burnup and criticality code system is described. This system links the spectrum codes from the SCALE4.1, WIMS7 and MCNP4A packages to the ORIGEN-S and FISPACT4.2 fuel depletion and activation codes, which enables us to perform very accurate burnup calculations in complicated three-dimensional goemetries. The data used by all codes are consistently based on the JEF2.2 evaluated nuclear data file. Some special features of OCTOPUS not available in other codes are described, as well as the validation of the system. (orig.).

  19. The octopus burnup and criticality code system

    International Nuclear Information System (INIS)

    Kloosterman, J.L.; Kuijper, J.C.; Leege, P.F.A. de.

    1996-01-01

    The OCTOPUS burnup and criticality code system is described. This system links the spectrum codes from the SCALE4.1, WIMS7 and MCNP4A packages to the ORIGEN-S and FISPACT4.2 fuel depletion and activation codes, which enables us to perform very accurate burnup calculations in complicated three-dimensional geometries. The data used by all codes are consistently based on the JEF2.2 evaluated nuclear data file. Some special features of OCTOPUS not available in other codes are described, as well as the validation of the system. (author)

  20. The OCTOPUS burnup and criticality code system

    International Nuclear Information System (INIS)

    Kloosterman, J.L.; Kuijper, J.C.; Leege, P.F.A. de

    1996-06-01

    The OCTOPUS burnup and criticality code system is described. This system links the spectrum codes from the SCALE4.1, WIMS7 and MCNP4A packages to the ORIGEN-S and FISPACT4.2 fuel depletion and activation codes, which enables us to perform very accurate burnup calculations in complicated three-dimensional goemetries. The data used by all codes are consistently based on the JEF2.2 evaluated nuclear data file. Some special features of OCTOPUS not available in other codes are described, as well as the validation of the system. (orig.)

  1. Percolation Systems away from the Critical Point

    OpenAIRE

    Dhar, Deepak

    2001-01-01

    This article reviews some effects of disorder in percolation systems even away from the critical density p_c. For densities below p_c, the statistics of large clusters defines the animals problem. Its relation to the directed animals problem and the Lee-Yang edge singularity problem is described. Rare compact clusters give rise to Griffiths singuraties in the free energy of diluted ferromagnets, and lead to a very slow relaxation of magnetization. In biassed diffusion on percolation clusters,...

  2. Chemical dosimetry system for criticality accidents.

    Science.gov (United States)

    Miljanić, Saveta; Ilijas, Boris

    2004-01-01

    Ruder Bosković Institute (RBI) criticality dosimetry system consists of a chemical dosimetry system for measuring the total (neutron + gamma) dose, and a thermoluminescent (TL) dosimetry system for a separate determination of the gamma ray component. The use of the chemical dosemeter solution chlorobenzene-ethanol-trimethylpentane (CET) is based on the radiolytic formation of hydrochloric acid, which protonates a pH indicator, thymolsulphonphthalein. The high molar absorptivity of its red form at 552 nm is responsible for a high sensitivity of the system: doses in the range 0.2-15 Gy can be measured. The dosemeter has been designed as a glass ampoule filled with the CET solution and inserted into a pen-shaped plastic holder. For dose determinations, a newly constructed optoelectronic reader has been used. The RBI team took part in the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002, with the CET dosimetry system. For gamma ray dose determination TLD-700 TL detectors were used. The results obtained with CET dosemeter show very good agreement with the reference values.

  3. Critical opalescence in the pure Coulomb system

    Science.gov (United States)

    Bobrov, V. B.; Trigger, S. A.

    2011-04-01

    Based on the dielectric formalism and quantum field theory methods, the phenomenon of critical opalescence is explained for light scattering in pure matter as a two-component electron-nuclear system with Coulomb interaction. A similar phenomenon is shown to occur in the case of neutron scattering in pure substances as well. The obtained results are valid for quantum case and arbitrary strong Coulomb interaction. Thus, the relations between structure factors derived for the electron-nuclear system are the exact result of the quantum statistical mechanics.

  4. Formal verification of algorithms for critical systems

    Science.gov (United States)

    Rushby, John M.; Von Henke, Friedrich

    1993-01-01

    We describe our experience with formal, machine-checked verification of algorithms for critical applications, concentrating on a Byzantine fault-tolerant algorithm for synchronizing the clocks in the replicated computers of a digital flight control system. First, we explain the problems encountered in unsynchronized systems and the necessity, and criticality, of fault-tolerant synchronization. We give an overview of one such algorithm, and of the arguments for its correctness. Next, we describe a verification of the algorithm that we performed using our EHDM system for formal specification and verification. We indicate the errors we found in the published analysis of the algorithm, and other benefits that we derived from the verification. Based on our experience, we derive some key requirements for a formal specification and verification system adequate to the task of verifying algorithms of the type considered. Finally, we summarize our conclusions regarding the benefits of formal verification in this domain, and the capabilities required of verification systems in order to realize those benefits.

  5. 3rd International Workshop on Critical Systems Development with UML

    OpenAIRE

    Jan Jürjens; Eduardo B. Fernandez; Robert France; Bernhard Rumpe

    2017-01-01

    Topics of the Workshop include: --- Applications of UML to real-time systems security-critical systems dependable / safety-critical systems performance-critical systems embedded systems hybrid systems reactive systems --- Extensions of UML (UML-RT, UMLsec, Automotive UML, Embedded UML, ...) and new developments (UML 2.0, MDA) --- Modeling, synthesis, model transformation, code generation, testing, validation, and verification of critical systems using UML --- Aspect-oriented or Component-base...

  6. Critical issues in NASA information systems

    Science.gov (United States)

    1987-01-01

    The National Aeronautics and Space Administration has developed a globally-distributed complex of earth resources data bases since LANDSAT 1 was launched in 1972. NASA envisages considerable growth in the number, extent, and complexity of such data bases, due to the improvements expected in its remote sensing data rates, and the increasingly multidisciplinary nature of its scientific investigations. Work already has begun on information systems to support multidisciplinary research activities based on data acquired by the space station complex and other space-based and terrestrial sources. In response to a request from NASA's former Associate Administrator for Space Science and Applications, the National Research Council convened a committee in June 1985 to identify the critical issues involving information systems support to space science and applications. The committee has suggested that OSSA address four major information systems issues; centralization of management functions, interoperability of user involvement in the planning and implementation of its programs, and technology.

  7. Critical Time Crystals in Dipolar Systems.

    Science.gov (United States)

    Ho, Wen Wei; Choi, Soonwon; Lukin, Mikhail D; Abanin, Dmitry A

    2017-07-07

    We analyze the quantum dynamics of periodically driven, disordered systems in the presence of long-range interactions. Focusing on the stability of discrete time crystalline (DTC) order in such systems, we use a perturbative procedure to evaluate its lifetime. For 3D systems with dipolar interactions, we show that the corresponding decay is parametrically slow, implying that robust, long-lived DTC order can be obtained. We further predict a sharp crossover from the stable DTC regime into a regime where DTC order is lost, reminiscent of a phase transition. These results are in good agreement with the recent experiments utilizing a dense, dipolar spin ensemble in diamond [Nature (London) 543, 221 (2017)NATUAS0028-083610.1038/nature21426]. They demonstrate the existence of a novel, critical DTC regime that is stabilized not by many-body localization but rather by slow, critical dynamics. Our analysis shows that the DTC response can be used as a sensitive probe of nonequilibrium quantum matter.

  8. Critical quench dynamics in confined systems.

    Science.gov (United States)

    Collura, Mario; Karevski, Dragi

    2010-05-21

    We analyze the coherent quantum evolution of a many-particle system after slowly sweeping a power-law confining potential. The amplitude of the confining potential is varied in time along a power-law ramp such that the many-particle system finally reaches or crosses a critical point. Under this protocol we derive general scaling laws for the density of excitations created during the nonadiabatic sweep of the confining potential. It is found that the mean excitation density follows an algebraic law as a function of the sweeping rate with an exponent that depends on the space-time properties of the potential. We confirm our scaling laws by first order adiabatic calculation and exact results on the Ising quantum chain with a varying transverse field.

  9. Plutonium Finishing Plant (PFP) Criticality Alarm System Commercial Grade Item (CGI) Critical Characteristics

    International Nuclear Information System (INIS)

    WHITE, W.F.

    1999-01-01

    This document specifies the critical characteristics for Commercial Grade Items (CGI) procured for PFP's criticality alarm system as required by HNF-PRO-268 and HNF-PRO-1819. These are the minimum specifications that the equipment must meet in order to properly perform its safety function. There may be several manufacturers or models that meet the critical characteristics for any one item. PFP's Criticality Alarm System includes the nine criticality alarm system panels and their associated hardware. This includes all parts up to the first breaker in the electrical distribution system. Specific system boundaries and justifications are contained in HNF-SD-CP-SDD-003, ''Definition and Means of Maintaining the Criticality Detectors and Alarms Portion of the PFP Safety Envelope.'' The procurement requirements associated with the system necessitates procurement of some system equipment as Commercial Grade Items in accordance with HNF-PRO-268, ''Control of Purchased Items and Services.''

  10. Critical behavior in the system cyclopentanone + water + secondary butyl alcohol

    Science.gov (United States)

    Krishna, U. Santhi; Unni, P. K. Madhavan

    2018-05-01

    We report detailed measurements of coexistence surface in the ternary system cylcopentanone + water + secondary butyl alcohol. The coexistence surface is seen to have an unusual tunnel like feature and is a potential system in which special critical points such as the Quadruple Critical Point (QCP) could be studied. Analysis of coexistence curves indicates that the system shows 3D-Ising like critical behavior.

  11. Nuclear Criticality Information System. Database examples

    Energy Technology Data Exchange (ETDEWEB)

    Foret, C.A.

    1984-06-01

    The purpose of this publication is to provide our users with a guide to using the Nuclear Criticality Information System (NCIS). It is comprised of an introduction, an information and resources section, a how-to-use section, and several useful appendices. The main objective of this report is to present a clear picture of the NCIS project and its available resources as well as assisting our users in accessing the database and using the TIS computer to process data. The introduction gives a brief description of the NCIS project, the Technology Information System (TIS), online user information, future plans and lists individuals to contact for additional information about the NCIS project. The information and resources section outlines the NCIS database and describes the resources that are available. The how-to-use section illustrates access to the NCIS database as well as searching datafiles for general or specific data. It also shows how to access and read the NCIS news section as well as connecting to other information centers through the TIS computer.

  12. Nuclear Criticality Information System. Database examples

    International Nuclear Information System (INIS)

    Foret, C.A.

    1984-06-01

    The purpose of this publication is to provide our users with a guide to using the Nuclear Criticality Information System (NCIS). It is comprised of an introduction, an information and resources section, a how-to-use section, and several useful appendices. The main objective of this report is to present a clear picture of the NCIS project and its available resources as well as assisting our users in accessing the database and using the TIS computer to process data. The introduction gives a brief description of the NCIS project, the Technology Information System (TIS), online user information, future plans and lists individuals to contact for additional information about the NCIS project. The information and resources section outlines the NCIS database and describes the resources that are available. The how-to-use section illustrates access to the NCIS database as well as searching datafiles for general or specific data. It also shows how to access and read the NCIS news section as well as connecting to other information centers through the TIS computer

  13. Critical management system for nuclear fuels

    International Nuclear Information System (INIS)

    Tai, Ichiro; Seki, Eiji.

    1981-01-01

    Purpose: To enable to provide display for the scale of accidents and critical state by detecting gamma-rays issued from nuclear fuels by gamma-ray level indicators to obtain outputs in proportion to the input level of the gamma-rays based on the detected pulse signals. Constitution: The gamma-ray level indicators comprises a plastic scintillator that emits light upon input of gamma-rays and a photomultiplier that amplifies weak fluorescence obtained from the scintillator. The photomultiplier is applied with a high voltage from a power source. A pre-amplifier amplifies pulse signals corresponding to individual gamma-rays at a high amplification factor and send them to a pulse counter circuit if the detected signal level from the gamma-ray level indicators is low, or amplifies the pulse detection signals at a low amplification factor and sends them to a voltage pulse averaging circuit if the detection signal level is high. A signal procession circuit selects the output from the pulse counter circuit or the voltage pulse averaging circuit. Thus, the system has a linear characteristic over a wide range equivalent to a wide range of incident gamma-rays. (Horiuchi, T.)

  14. 'System-of-systems' approach for interdependent critical infrastructures

    International Nuclear Information System (INIS)

    Eusgeld, Irene; Nan, Cen; Dietz, Sven

    2011-01-01

    The study of the interdependencies within critical infrastructures (CI) is a growing field of research as the importance of potential failure propagation among infrastructures may lead to cascades affecting all supply networks. New powerful methods are required to model and describe such 'systems-of-systems' (SoS) as a whole. An overall model is required to provide security and reliability assessment taking into account various kinds of threats and failures. A significant challenge associated with this model may be to create 'what-if' scenarios for the analysis of interdependencies. In this paper the interdependencies between industrial control systems (ICS), in particular SCADA (Supervisory Control and Data Acquisition), and the underlying critical infrastructures to address the vulnerabilities related to the coupling of these systems are analyzed. The modeling alternatives for system-of-systems, integrated versus coupled models, are discussed. An integrated model contains detailed low level models of (sub)systems as well as a high level model, covering all hierarchical levels. On the other hand, a coupled model aggregates different simulated outputs of the low level models as inputs at a higher level. Strengths and weaknesses of both approaches are analyzed and a model architecture for SCADA and the 'system under control' are proposed. Furthermore, the HLA simulation standard is introduced and discussed in this paper as a promising approach to represent interdependencies between infrastructures. To demonstrate the capabilities of the HLA standard for the interdependencies study, an exemplary application and some first results are also briefly presented in this paper.

  15. Why Mission-Critical Systems Are Critical to the Future of Academic Libraries

    Science.gov (United States)

    Oberlander, Cyril

    2012-01-01

    A mission-critical system is one that is so intertwined with the operation of an organization that the organization can scarcely function without it. Just as in corporations, mission-critical library systems offer the capability to unlock talent and time. They are essential to the transformation of higher education and the learning environment. A…

  16. Percolation systems away from the critical point

    Indian Academy of Sciences (India)

    DEEPAK DHAR. Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India ... There is more to percolation theory than the critical exponents. Of course, an experi- .... simple qualitative arguments. In the summation ...

  17. Critical behavior of non-ideal systems

    CERN Document Server

    Ivanov, Dmitry Yu

    2008-01-01

    Dmitry Yu. Ivanov is a professor at the Baltic State Technical University (St. Petersburg, Russia). His research focuses on thermodynamics, critical phenomena and phase transitions, theoretical and experimental investigations of multiple light scattering and correlation spectroscopy in application to Material Science and critical phenomena. His research activities included projects at the Nuclear Research Center in Dubna and Krichevsky Laboratory (Russia) and at the CNRS laboratories and Universities of Paris and Nice (France). He has authored about 70 scientific publications.

  18. Dynamical critical phenomena in driven-dissipative systems.

    Science.gov (United States)

    Sieberer, L M; Huber, S D; Altman, E; Diehl, S

    2013-05-10

    We explore the nature of the Bose condensation transition in driven open quantum systems, such as exciton-polariton condensates. Using a functional renormalization group approach formulated in the Keldysh framework, we characterize the dynamical critical behavior that governs decoherence and an effective thermalization of the low frequency dynamics. We identify a critical exponent special to the driven system, showing that it defines a new dynamical universality class. Hence critical points in driven systems lie beyond the standard classification of equilibrium dynamical phase transitions. We show how the new critical exponent can be probed in experiments with driven cold atomic systems and exciton-polariton condensates.

  19. The evaluation of set of criticality parameters using scale system

    International Nuclear Information System (INIS)

    Abe, Alfredo; Sanchez, Andrea; Yamaguchi, Mistuo

    2009-01-01

    In evaluating the criticality safety of the nuclear fuel facility, it is important to apply a consistent methodology, which consider every aspects concerning various types of criticality parameters. Usually, the critical parameters are compiled and arranged into handbooks, and these handbooks are based on experience with nuclear facilities, experimental data from criticality safety research facilities, and theoretical studies performed using numerical simulations. Most of criticality safety evaluation can be addressed using the criticality parameters data directly from handbook, but some critical parameters for a specific chemical mixtures and/or enrichment are not be available. Consequently, not available parameters has to be evaluated. This work present the methodology to evaluate a set of critical parameters using SCALE system for various types of mixtures present at nuclear fuel cycle facilities for two different level of enrichment, the results are verified in the independent calculation using MCNP Monte Carlo Code. (author)

  20. A critical systems perspective on the design of organizational space

    NARCIS (Netherlands)

    Mobach, Mark P.

    2007-01-01

    This paper is the first to introduce critical systems thinking into a new emerging research strand: the design of organizational space. The study revealed two things. First, critical systems thinking provides a thorough framework to understand the possibilities to connect organization and building;

  1. "Actionable" critical success factors for supply chain information system implementations

    NARCIS (Netherlands)

    Denolf, Janne M.; Trienekens, Jacques H.; Nel Wognum, P.M.; Schütz, Verena; Vorst, Van Der Jack G.A.J.; Onno Omta, S.W.F.

    2018-01-01

    Implementing a supply chain information system (SCIS) incurs organizational and technical complexities. For managing these complexities, information system researchers have identified generic critical success factors. However, CSFs are abstract and, therefore, difficult to use in practice. To

  2. System Hardening Architecture for Safer Access to Critical Business ...

    African Journals Online (AJOL)

    System Hardening Architecture for Safer Access to Critical Business Data. ... and the threat is growing faster than the potential victims can deal with. ... in this architecture are applied to the host, application, operating system, user, and the ...

  3. Design criteria and principles for criticality detection and alarm systems

    International Nuclear Information System (INIS)

    Delafield, H.J.; Clifton, J.J.

    1984-10-01

    The report gives design principles and criteria for criticality detection and alarm systems based on earlier work and revised in the light of more recent experience. In particular, account is taken of the developments which have taken place in the field of radiation detection and in the understanding of the different types of criticality excursion. General guidance is given on the principles to apply in deciding upon the need for a criticality system. The characteristics of a criticality incident are described in terms of the minimum incident of concern, and the radiation field. Criteria for the threshold of detection of a criticality incident are then derived and the methods of detection considered. The selection and siting of criticality detectors is discussed, and design principles are given for alarm systems. Finally, testing and post-alarm procedures are outlined, followed by a summary of the principal recommendations. The supporting Appendices include a discussion of reliability and a summary of radiation detector characteristics. (author)

  4. Rationing in health systems: A critical review.

    Science.gov (United States)

    Keliddar, Iman; Mosadeghrad, Ali Mohammad; Jafari-Sirizi, Mehdi

    2017-01-01

    Background: It is difficult to provide health care services to all those in need of such services due to limited resources and unlimited demands. Thus, priority setting and rationing have to be applied. This study aimed at critically examining the concept of rationing in health sector and identifying its purposes, influencing factors, mechanisms, and outcomes. Methods: The critical interpretive synthesis methodology was used in this study. PubMed, Cochrane, and Proquest databases were searched using the related key words to find related documents published between 1970 and 2015. In total, 161 published reports were reviewed and included in the study. Thematic content analysis was applied for data analysis. Results: Health services rationing means restricting the access of some people to useful or potentially useful health services due to budgetary limitation. The inherent features of the health market and health services, limited resources, and unlimited needs necessitate health services rationing. Rationing can be applied in 4 levels: health care policy- makers, health care managers, health care providers, and patients. Health care rationing can be accomplished through fixed budget, benefit package, payment mechanisms, queuing, copayments, and deductibles. Conclusion: This paper enriched our understanding of health services rationing and its mechanisms at various levels and contributed to the literature by broadly conceptualizing health services rationing.

  5. Sensor Systems Collect Critical Aerodynamics Data

    Science.gov (United States)

    2010-01-01

    With the support of Small Business Innovation Research (SBIR) contracts with Dryden Flight Research Center, Tao of Systems Integration Inc. developed sensors and other components that will ultimately form a first-of-its-kind, closed-loop system for detecting, measuring, and controlling aerodynamic forces and moments in flight. The Hampton, Virginia-based company commercialized three of the four planned components, which provide sensing solutions for customers such as Boeing, General Electric, and BMW and are used for applications such as improving wind turbine operation and optimizing air flow from air conditioning systems. The completed system may one day enable flexible-wing aircraft with flight capabilities like those of birds.

  6. Status, plans, and capabilities of the Nuclear Criticality Information System

    International Nuclear Information System (INIS)

    Koponen, B.L.

    1984-01-01

    The Nuclear Criticality Information System (NCIS), in preparation since 1981, has substantially evolved and now contains a growing number of resources pertinent to nuclear criticality safety. These resources include bibliographic compilations, experimental data, communications media, and the International Directory of Nuclear Criticality Safety Personnel. These resources are part of the LLNL Technology Information System (TIS) which provides the host computer for NCIS. The TIS provides nationwide access to authorized members of the nuclear criticality community via interactive dial-up from computer terminals that utilize communication facilities such as commercial and federal telephone networks, toll-free WATS lines, TYMNET, and the ARPANET/MILNET computer network

  7. SCALE system cross-section validation for criticality safety analysis

    International Nuclear Information System (INIS)

    Hathout, A.M.; Westfall, R.M.; Dodds, H.L. Jr.

    1980-01-01

    The purpose of this study is to test selected data from three cross-section libraries for use in the criticality safety analysis of UO 2 fuel rod lattices. The libraries, which are distributed with the SCALE system, are used to analyze potential criticality problems which could arise in the industrial fuel cycle for PWR and BWR reactors. Fuel lattice criticality problems could occur in pool storage, dry storage with accidental moderation, shearing and dissolution of irradiated elements, and in fuel transport and storage due to inadequate packing and shipping cask design. The data were tested by using the SCALE system to analyze 25 recently performed critical experiments

  8. 'Critical' behaviour of weakly bound systems

    International Nuclear Information System (INIS)

    Lassaut, M.; Lombard, R.J.; Bulboaca, I.

    1995-11-01

    The class of 3-dimensional finite range or similar potentials λW(r) is discussed, depending on a strength constant λ. The behaviour of the eigenvalue E as function of λ-λ c is studied, where λ c is the critical value at the transition from 0 → 1 bound state. For the l=0 case, E α (λ-λ c ) 2 was found, whereas the relationship is linear for l≥1. Treating l as a continuous parameter in the radial Schroedinger equation, the evolution of the power-law between l=0 and l=1 is given. Besides spherically symmetric scalar potentials, the case of a repulsive scalar potential combined with a spin-orbit component of the Thomas form is also discussed. (author)

  9. Life-critical digital flight control systems

    Science.gov (United States)

    Mcwha, James

    1990-01-01

    Digital autopilot systems were first used on commercial airplanes in the late 1970s. The A-320 airplane was the first air transport airplane with a fly-by-wire primary flight control system. On the 767-X (777) airplane Boeing will install all fly-by-wire flight controls. Activities related to safety, industry status and program phases are discussed.

  10. Utilization of Keno system for criticality calculation

    International Nuclear Information System (INIS)

    Maragni, M.G.

    1990-01-01

    Several studies involving benchmarks have been performed with the KENO-IV code in order to utilize it in a more efficient way at IPEN-COPESP. The influence of different cross section libraries has been verifed. The Hansen-Roach library produced better results for fast systems, while GAMTEC-II code was more efficient for thermal systems. For reflectors it has been shown that the differential albedo and automatic reflection options are more appropriate for infinite and finite reflectors, respectively. A number of histories greater than 30.000 did not seem to improve the results. Plutonium systems should be treated with special care. (author) [pt

  11. Systemic trade risk of critical resources.

    Science.gov (United States)

    Klimek, Peter; Obersteiner, Michael; Thurner, Stefan

    2015-11-01

    In the wake of the 2008 financial crisis, the role of strongly interconnected markets in causing systemic instability has been increasingly acknowledged. Trade networks of commodities are susceptible to cascades of supply shocks that increase systemic trade risks and pose a threat to geopolitical stability. We show that supply risk, scarcity, and price volatility of nonfuel mineral resources are intricately connected with the structure of the worldwide trade networks spanned by these resources. At the global level, we demonstrate that the scarcity of a resource is closely related to the susceptibility of the trade network with respect to cascading shocks. At the regional level, we find that, to some extent, region-specific price volatility and supply risk can be understood by centrality measures that capture systemic trade risk. The resources associated with the highest systemic trade risk indicators are often those that are produced as by-products of major metals. We identify significant strategic shortcomings in the management of systemic trade risk, in particular in the European Union.

  12. Criticality monitoring with digital systems and solid state neutron detectors

    International Nuclear Information System (INIS)

    Willhoite, S.B.

    1984-01-01

    A commercially available system for criticality monitoring combines the well established technology of digital radiation monitoring with state-of-the art detector systems capable of detecting criticality excursions of varying length and intensity with a high degree of confidence. The field microcomputer servicing the detector clusters contains hardware and software to acquire detector information in both the digital count rate and bit sensing modes supported by the criticality detectors. In both cases special criticality logic in the field microcomputer is used to determine the validity of the criticality event. The solid-state neutron detector consists of a 6 LiF wafer coupled to a diffused-junction charged particle detector. Alpha particles resulting from (n,α) interactions within the lithium wafer produce a pulsed signal corresponding to neutron intensity. Special detector circuitry causes the setting of a criticality bit recognizable by the microcomputer should neutron field intensities either exceed a hardware selectable frequency or saturate the detector resulting in a high current condition. These two modes of criticality sensing, in combination with the standard method of comparing an operator selectable alarm setpoint with the detector count rate, results in a criticality system capable of effective operation under the most demanding criticality monitoring conditions

  13. Criticality calculation of non-ordinary systems

    Energy Technology Data Exchange (ETDEWEB)

    Kalugin, A. V., E-mail: Kalugin-AV@nrcki.ru; Tebin, V. V. [National Research Centre Kurchatov Institute (Russian Federation)

    2016-12-15

    The specific features of calculation of the effective multiplication factor using the Monte Carlo method for weakly coupled and non-asymptotic multiplying systems are discussed. Particular examples are considered and practical recommendations on detection and Monte Carlo calculation of systems typical in numerical substantiation of nuclear safety for VVER fuel management problems are given. In particular, the problems of the choice of parameters for the batch mode and the method for normalization of the neutron batch, as well as finding and interpretation of the eigenvalue spectrum for the integral fission matrix, are discussed.

  14. Comparison study of hybrid VS critical systems in point kinetics

    International Nuclear Information System (INIS)

    Ritter, G.; Tommasi, J.; Slessarev, L.; Salvatores, M.; Mouney, H.; Vergnes, J.

    1999-01-01

    An essential motivation for hybrid systems is a potentially high level of intrinsic safety against reactivity accidents. In this respect, it is necessary to assess the behaviour of an Accelerator Driven System during a TOP, LOF or TOC accident. A comparison between a critical and sub-critical reactor shows a larger sensitivity for the critical system. The ADS has an unquestionable advantage in case of TOP but a less favourable behaviour as for LOFWS type of accidents. However in the ADS cases, the beam could be easily shut off during the transient. Therefore, a part of the R and D effort should be focused on the monitoring and control of power. (author)

  15. Systems approach critical to agroecosystems management

    Science.gov (United States)

    Sustainable dryland agriculture in the semi-arid Great Plains of the U.S. depends on achieving economic yields while maintaining soil resources. The traditional system of conventional tillage wheat-fallow was vulnerable to excessive soil erosion which resulted in excessive organic matter loss. No-...

  16. Triggers for the critical engagement with decision support systems

    NARCIS (Netherlands)

    Hartmann, Timo; Javernick-Will, A.; Chinowsky, P.

    2012-01-01

    In previous work, we showed that the critical engagement with a decision sup- port system during its implementation by a project team is an important an- tecedent for the successful later use of the technology. However, the mechanisms that trigger such critical engagement are so far not well

  17. Critical issues in an electronic documentation system.

    Science.gov (United States)

    Weir, Charlene R; Nebeker, Jonathan R

    2007-10-11

    The Veterans Health Administration (VHA), of the U.S. Department of Veteran Affairs has instituted a medical record (EMR) that includes electronic documentation of all narrative components of the medical record. To support clinicians using the system, multiple efforts have been instituted to ease the creation of narrative reports. Although electronic documentation is easier to read and improves access to information, it also may create new and additional hazards for users. This study is the first step in a series of studies to evaluate the issues surrounding the creation and use of electronic documentation. Eighty-eight providers across multiple clinical roles were interviewed in 10 primary care sites in the VA system. Interviews were tape-recorded, transcribed and qualitatively analyzed for themes. In addition, specific questions were asked about perceived harm due to electronic documentation practices. Five themes relating to difficulties with electronic documentation were identified: 1) information overload; 2) hidden information; 3) lack of trust; 4) communication; 5) decision-making. Three providers reported that they knew of an incident where current documentation practices had caused patient harm and over 75% of respondents reported significant mis-trust of the system.

  18. Nuclear data requirements for accelerator driven sub-critical systems

    Indian Academy of Sciences (India)

    The development of accelerator driven sub-critical systems (ADSS) require significant amount of new nuclear data in extended energy regions as well as for a variety of new materials. This paper reviews these perspectives in the Indian context.

  19. Cognitive systems engineering analysis of the JCO criticality accident

    International Nuclear Information System (INIS)

    Tanabe, Fumiya; Yamaguchi, Yukichi

    2000-01-01

    The JCO Criticality Accident is analyzed with a framework based on cognitive systems engineering. With the framework, analysis is conducted integrally both from the system viewpoint and actors viewpoint. The occupational chemical risk was important as safety constraint for the actors as well as the nuclear risk, which is due to criticality accident, to the public and to actors. The inappropriate actor's mental model of the work system played a critical role and several factors (e.g. poor training and education, lack of information on criticality safety control in the procedures and instructions, and lack of warning signs at workplace) contributed to form and shape the mental model. Based on the analysis, several countermeasures, such as warning signs, information system for supporting actors and improved training and education, are derived to prevent such an accident. (author)

  20. CRITICAL INFORMATION INFRASTRUCTURE SECURITY - NETWORK INTRUSION DETECTION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Cristea DUMITRU

    2011-12-01

    Full Text Available Critical Information Infrastructure security will always be difficult to ensure, just because of the features that make it irreplaceable tor other critical infrastructures normal operation. It is decentralized, interconnected interdependent, controlled by multiple actors (mainly private and incorporating diverse types of technologies. It is almost axiomatic that the disruption of the Critical Information Infrastructure affects systems located much farther away, and the cyber problems have direct consequences on the real world. Indeed the Internet can be used as a multiplier in order to amplify the effects of an attack on some critical infrastructures. Security challenges increase with the technological progress. One of the last lines of defense which comes to complete the overall security scheme of the Critical Information Infrastructure is represented by the Network Intrusion Detection Systems.

  1. Systems thinking, critical realism and philosophy a confluence of ideas

    CERN Document Server

    Mingers, John

    2014-01-01

    Systems Thinking, Critical Realism and Philosophy: A Confluence of Ideas seeks to re-address the whole question of philosophy and systems thinking for the twenty first century and provide a new work that would be of value to both systems and philosophy. This is a highly opportune time when different fields - critical realism, philosophy of science and systems thinking - are all developing around the same set of concepts and yet not realizing it. This book will be of interest to the academic systems community worldwide and due to it's interdisciplinary coverage, it will also

  2. A Critical Systems Metamethodology for Problem Situation Structuring

    OpenAIRE

    Slavica P. Petrovic

    2012-01-01

    The increasing complexity and diversity of management problem situations in organizations, as well as the increasing variety of theories, methodologies, methods, techniques, and models that can be employed in problem situation structuring and solving, must be considered as relevant aspects of management process in contemporary circumstances. Creative holism in management problem situations in organizations is enabled by means of Critical Systems Thinking (CST) as well as Critical Systems Prac...

  3. Computational methods for criticality safety analysis within the scale system

    International Nuclear Information System (INIS)

    Parks, C.V.; Petrie, L.M.; Landers, N.F.; Bucholz, J.A.

    1986-01-01

    The criticality safety analysis capabilities within the SCALE system are centered around the Monte Carlo codes KENO IV and KENO V.a, which are both included in SCALE as functional modules. The XSDRNPM-S module is also an important tool within SCALE for obtaining multiplication factors for one-dimensional system models. This paper reviews the features and modeling capabilities of these codes along with their implementation within the Criticality Safety Analysis Sequences (CSAS) of SCALE. The CSAS modules provide automated cross-section processing and user-friendly input that allow criticality safety analyses to be done in an efficient and accurate manner. 14 refs., 2 figs., 3 tabs

  4. Program computes single-point failures in critical system designs

    Science.gov (United States)

    Brown, W. R.

    1967-01-01

    Computer program analyzes the designs of critical systems that will either prove the design is free of single-point failures or detect each member of the population of single-point failures inherent in a system design. This program should find application in the checkout of redundant circuits and digital systems.

  5. An Architecture Design Method for Critical Embedded Systems

    NARCIS (Netherlands)

    Feitosa, Daniel

    2014-01-01

    Critical embedded systems (CES) have become ubiquitous in the modern society, like in cars and energy appliances. However, besides their popularity, engineering of these systems is still particularly challenging. One of the greatest challenges in the development of such systems is their expected

  6. Surveying the critical success factors of BPM-systems implementation.

    NARCIS (Netherlands)

    Ravesteyn, P.; Batenburg, R.

    2010-01-01

    Purpose – The purpose of this paper is to explore if there is a common ground for the definition of business process management (BPM) and BPM-systems, as well as the critical success factors (CSFs) for BPM-system implementation. A BPM-system implementation framework is validated that classifies the

  7. Formal methods for industrial critical systems a survey of applications

    CERN Document Server

    Margaria-Steffen, Tiziana

    2012-01-01

    "Today, formal methods are widely recognized as an essential step in the design process of industrial safety-critical systems. In its more general definition, the term formal methods encompasses all notations having a precise mathematical semantics, together with their associated analysis methods, that allow description and reasoning about the behavior of a system in a formal manner.Growing out of more than a decade of award-winning collaborative work within the European Research Consortium for Informatics and Mathematics, Formal Methods for Industrial Critical Systems: A Survey of Applications presents a number of mainstream formal methods currently used for designing industrial critical systems, with a focus on model checking. The purpose of the book is threefold: to reduce the effort required to learn formal methods, which has been a major drawback for their industrial dissemination; to help designers to adopt the formal methods which are most appropriate for their systems; and to offer a panel of state-of...

  8. Systems modeling and simulation applications for critical care medicine

    Science.gov (United States)

    2012-01-01

    Critical care delivery is a complex, expensive, error prone, medical specialty and remains the focal point of major improvement efforts in healthcare delivery. Various modeling and simulation techniques offer unique opportunities to better understand the interactions between clinical physiology and care delivery. The novel insights gained from the systems perspective can then be used to develop and test new treatment strategies and make critical care delivery more efficient and effective. However, modeling and simulation applications in critical care remain underutilized. This article provides an overview of major computer-based simulation techniques as applied to critical care medicine. We provide three application examples of different simulation techniques, including a) pathophysiological model of acute lung injury, b) process modeling of critical care delivery, and c) an agent-based model to study interaction between pathophysiology and healthcare delivery. Finally, we identify certain challenges to, and opportunities for, future research in the area. PMID:22703718

  9. Systems modeling and simulation applications for critical care medicine.

    Science.gov (United States)

    Dong, Yue; Chbat, Nicolas W; Gupta, Ashish; Hadzikadic, Mirsad; Gajic, Ognjen

    2012-06-15

    Critical care delivery is a complex, expensive, error prone, medical specialty and remains the focal point of major improvement efforts in healthcare delivery. Various modeling and simulation techniques offer unique opportunities to better understand the interactions between clinical physiology and care delivery. The novel insights gained from the systems perspective can then be used to develop and test new treatment strategies and make critical care delivery more efficient and effective. However, modeling and simulation applications in critical care remain underutilized. This article provides an overview of major computer-based simulation techniques as applied to critical care medicine. We provide three application examples of different simulation techniques, including a) pathophysiological model of acute lung injury, b) process modeling of critical care delivery, and c) an agent-based model to study interaction between pathophysiology and healthcare delivery. Finally, we identify certain challenges to, and opportunities for, future research in the area.

  10. A Cost Effective System Design Approach for Critical Space Systems

    Science.gov (United States)

    Abbott, Larry Wayne; Cox, Gary; Nguyen, Hai

    2000-01-01

    NASA-JSC required an avionics platform capable of serving a wide range of applications in a cost-effective manner. In part, making the avionics platform cost effective means adhering to open standards and supporting the integration of COTS products with custom products. Inherently, operation in space requires low power, mass, and volume while retaining high performance, reconfigurability, scalability, and upgradability. The Universal Mini-Controller project is based on a modified PC/104-Plus architecture while maintaining full compatibility with standard COTS PC/104 products. The architecture consists of a library of building block modules, which can be mixed and matched to meet a specific application. A set of NASA developed core building blocks, processor card, analog input/output card, and a Mil-Std-1553 card, have been constructed to meet critical functions and unique interfaces. The design for the processor card is based on the PowerPC architecture. This architecture provides an excellent balance between power consumption and performance, and has an upgrade path to the forthcoming radiation hardened PowerPC processor. The processor card, which makes extensive use of surface mount technology, has a 166 MHz PowerPC 603e processor, 32 Mbytes of error detected and corrected RAM, 8 Mbytes of Flash, and I Mbytes of EPROM, on a single PC/104-Plus card. Similar densities have been achieved with the quad channel Mil-Std-1553 card and the analog input/output cards. The power management built into the processor and its peripheral chip allows the power and performance of the system to be adjusted to meet the requirements of the application, allowing another dimension to the flexibility of the Universal Mini-Controller. Unique mechanical packaging allows the Universal Mini-Controller to accommodate standard COTS and custom oversized PC/104-Plus cards. This mechanical packaging also provides thermal management via conductive cooling of COTS boards, which are typically

  11. Critical phenomena in quasi-two-dimensional vibrated granular systems.

    Science.gov (United States)

    Guzmán, Marcelo; Soto, Rodrigo

    2018-01-01

    The critical phenomena associated to the liquid-to-solid transition of quasi-two-dimensional vibrated granular systems is studied using molecular dynamics simulations of the inelastic hard sphere model. The critical properties are associated to the fourfold bond-orientational order parameter χ_{4}, which measures the level of square crystallization of the system. Previous experimental results have shown that the transition of χ_{4}, when varying the vibration amplitude, can be either discontinuous or continuous, for two different values of the height of the box. Exploring the amplitude-height phase space, a transition line is found, which can be either discontinuous or continuous, merging at a tricritical point and the continuous branch ends in an upper critical point. In the continuous transition branch, the critical properties are studied. The exponent associated to the amplitude of the order parameter is β=1/2, for various system sizes, in complete agreement with the experimental results. However, the fluctuations of χ_{4} do not show any critical behavior, probably due to crossover effects by the close presence of the tricritical point. Finally, in quasi-one-dimensional systems, the transition is only discontinuous, limited by one critical point, indicating that two is the lower dimension for having a tricritical point.

  12. Network Randomization and Dynamic Defense for Critical Infrastructure Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Adrian R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Mitchell Tyler [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hamlet, Jason [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stout, William M.S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lee, Erik [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-04-01

    Critical Infrastructure control systems continue to foster predictable communication paths, static configurations, and unpatched systems that allow easy access to our nation's most critical assets. This makes them attractive targets for cyber intrusion. We seek to address these attack vectors by automatically randomizing network settings, randomizing applications on the end devices themselves, and dynamically defending these systems against active attacks. Applying these protective measures will convert control systems into moving targets that proactively defend themselves against attack. Sandia National Laboratories has led this effort by gathering operational and technical requirements from Tennessee Valley Authority (TVA) and performing research and development to create a proof-of-concept solution. Our proof-of-concept has been tested in a laboratory environment with over 300 nodes. The vision of this project is to enhance control system security by converting existing control systems into moving targets and building these security measures into future systems while meeting the unique constraints that control systems face.

  13. Critical behavior of spin systems with quenched disorder

    International Nuclear Information System (INIS)

    Murtazaev, Akai K.; Kamilov, Ibragimkhan K.; Babaev, Albert B.

    2006-01-01

    A static critical behavior of three-dimensional diluted quenched Ising model on a cubic lattice is studied by Monte-Carlo methods. The static critical exponents of a specific heat α, susceptibility γ, magnetization β and exponent of correlation radius ν in a wide interval of change the values of spin concentrations p are calculated on the basis of the finite-size scaling theory using the common technique. The problem about universality classes of critical behavior for three-dimensional diluted systems is considered

  14. Intelligent monitoring, control, and security of critical infrastructure systems

    CERN Document Server

    Polycarpou, Marios

    2015-01-01

    This book describes the challenges that critical infrastructure systems face, and presents state of the art solutions to address them. How can we design intelligent systems or intelligent agents that can make appropriate real-time decisions in the management of such large-scale, complex systems? What are the primary challenges for critical infrastructure systems? The book also provides readers with the relevant information to recognize how important infrastructures are, and their role in connection with a society’s economy, security and prosperity. It goes on to describe state-of-the-art solutions to address these points, including new methodologies and instrumentation tools (e.g. embedded software and intelligent algorithms) for transforming and optimizing target infrastructures. The book is the most comprehensive resource to date for professionals in both the private and public sectors, while also offering an essential guide for students and researchers in the areas of modeling and analysis of critical in...

  15. Traceability of Software Safety Requirements in Legacy Safety Critical Systems

    Science.gov (United States)

    Hill, Janice L.

    2007-01-01

    How can traceability of software safety requirements be created for legacy safety critical systems? Requirements in safety standards are imposed most times during contract negotiations. On the other hand, there are instances where safety standards are levied on legacy safety critical systems, some of which may be considered for reuse for new applications. Safety standards often specify that software development documentation include process-oriented and technical safety requirements, and also require that system and software safety analyses are performed supporting technical safety requirements implementation. So what can be done if the requisite documents for establishing and maintaining safety requirements traceability are not available?

  16. Detection of criticality accidents. The Intertechnique EDAC II system

    International Nuclear Information System (INIS)

    Prigent, R.

    1991-01-01

    The chief aim of the new generation of EDAC II criticality accidents detection system is to reduce the risks associated to the handling of fissile material by providing a swift and safe warning of the development of any criticality accident. To this function already devolving on the EDAC system of the previous generation, the EDAC II adds the possibility of storing in memory the characteristics of the accident, providing a daily follow-up of the striking events in the system through the print-out of a log book and providing assistance to the operators during the periodical tests. (Author)

  17. On Critical Behaviour in Systems of Hamiltonian Partial Differential Equations.

    Science.gov (United States)

    Dubrovin, Boris; Grava, Tamara; Klein, Christian; Moro, Antonio

    2015-01-01

    We study the critical behaviour of solutions to weakly dispersive Hamiltonian systems considered as perturbations of elliptic and hyperbolic systems of hydrodynamic type with two components. We argue that near the critical point of gradient catastrophe of the dispersionless system, the solutions to a suitable initial value problem for the perturbed equations are approximately described by particular solutions to the Painlevé-I (P[Formula: see text]) equation or its fourth-order analogue P[Formula: see text]. As concrete examples, we discuss nonlinear Schrödinger equations in the semiclassical limit. A numerical study of these cases provides strong evidence in support of the conjecture.

  18. Tank waste remediation system nuclear criticality safety program management review

    International Nuclear Information System (INIS)

    BRADY RAAP, M.C.

    1999-01-01

    This document provides the results of an internal management review of the Tank Waste Remediation System (TWRS) criticality safety program, performed in advance of the DOE/RL assessment for closure of the TWRS Nuclear Criticality Safety Issue, March 1994. Resolution of the safety issue was identified as Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-40-12, due September 1999

  19. Acknowledging the Infrasystem: A Critical Feminist Analysis of Systems Theory.

    Science.gov (United States)

    Creedon, Pamela J.

    1993-01-01

    Examines the absence of a critical feminist perspective in the application of systems theory as a unifying model for public relations. Describes an unacknowledged third system, the infrasystem, that constructs both suprasystem and subsystem interactions. Concludes with a case analysis of sport as illustration. (HB)

  20. Critical assessment of Nigeria criminal justice system and the ...

    African Journals Online (AJOL)

    Critical assessment of Nigeria criminal justice system and the perennial problem of awaiting trial in Port Harcourt maximum prison, Rivers State. ... Global Journal of Social Sciences ... Keywords: Nigeria criminal justice system, awaiting trial, rigidity of the penal law, holding charges, delay in the disposal of cases ...

  1. Critical experiments analysis by ABBN-90 constant system

    Energy Technology Data Exchange (ETDEWEB)

    Tsiboulia, A.; Nikolaev, M.N.; Golubev, V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)] [and others

    1997-06-01

    The ABBN-90 is a new version of the well-known Russian group-constant system ABBN. Included constants were calculated based on files of evaluated nuclear data from the BROND-2, ENDF/B-VI, and JENDL-3 libraries. The ABBN-90 is intended for the calculation of different types of nuclear reactors and radiation shielding. Calculations of criticality safety and reactivity accidents are also provided by using this constant set. Validation of the ABBN-90 set was made by using a computerized bank of evaluated critical experiments. This bank includes the results of experiments conducted in Russia and abroad of compact spherical assemblies with different reflectors, fast critical assemblies, and fuel/water-solution criticalities. This report presents the results of the calculational analysis of the whole collection of critical experiments. All calculations were produced with the ABBN-90 group-constant system. Revealed discrepancies between experimental and calculational results and their possible reasons are discussed. The codes and archives INDECS system is also described. This system includes three computerized banks: LEMEX, which consists of evaluated experiments and their calculational results; LSENS, which consists of sensitivity coefficients; and LUND, which consists of group-constant covariance matrices. The INDECS system permits us to estimate the accuracy of neutronics calculations. A discussion of the reliability of such estimations is finally presented. 16 figs.

  2. The nuclear criticality information system's project to archive unpublished critical experiment data

    International Nuclear Information System (INIS)

    Koponen, B.L.; Doherty, A.L.; Clayton, E.D.

    1991-01-01

    Critical experiment facilities produced a large amount of important data during the past forty-five years. However, much useful data remains unpublished. The unpublished material exists in the form of experimenters' logbooks, notes, photographs, material descriptions, etc. These data could be important for computer code validation, understanding the physics of criticality, facility design, or for setting process limits. In the past, criticality specialists have been able to obtain unpublished details by direct contact with the experimenters. The closure of facilities and the loss of personnel is likely to lead to the loss of the facility records unless an effort is made to ensure that the records are preserved. It has been recognized for some time that the unpublished records of critical experiment facilities comprise a valuable resource, thus the Nuclear Criticality Information System (NCIS) is working to ensure that the records are preserved and made available via NCIS. As a first step in the archiving project, we identified criteria to help judge which series of experiments should be considered for archiving. Data that are used for validating calculations or the basis for subcritical limits in standards, handbooks, and guides are of particular importance. In this paper we will discuss the criteria for archiving, the priority list of experiments for archiving, and progress in developing an NCIS image database using current CD-ROM technology. (Author)

  3. The generation IV nuclear reactor systems - Energy of future

    International Nuclear Information System (INIS)

    Ohai, Dumitru; Jianu, Adrian

    2006-01-01

    Ten nations joined within the Generation IV International Forum (GIF), agreeing on a framework for international cooperation in research. Their goal is to develop future-generation nuclear energy systems that can be licensed, constructed, and operated in an economically competitive way while addressing the issues of safety, proliferation, and other public perception concerns. The objective is for the Gen IV systems to be available for deployment by 2030. Using more than 100 nuclear experts from its 10 member nations, the GIF has developed a Gen IV Technology Roadmap to guide the research and development of the world's most advanced, efficient and safe nuclear power systems. The Gen IV Technology Roadmap calls for extensive research and development of six different potential future reactor systems. These include water-cooled, gas-cooled, liquid metal-cooled and nonclassical systems. One or more of these reactor systems will provide the best combination of safety, reliability, efficiency and proliferation resistance at a competitive cost. The main goals for the Gen IV Nuclear Energy Systems are: - Provide sustainable energy generation that meets clean air objectives and promotes long-term availability of systems and effective fuel use for worldwide energy production; - Minimize and manage their nuclear waste and noticeably reduce the long-term stewardship burden in the future, improving the protection of public health and the environment; - Increase the assurance that these reactors are very unattractive and the least desirable route for diversion or theft of weapons-usable materials, and provide increased protection against acts of terrorism; - Have a clear life-cycle cost advantage over other energy sources; - Have a level of financial risk comparable to other energy projects; - Excel in safety and reliability; - Have a low likelihood and degree of reactor core damage. (authors)

  4. Assessments of the kinetic and dynamic transient behavior of sub-critical systems (ADS) in comparison to critical reactor systems

    International Nuclear Information System (INIS)

    Schikorr, W.M.

    2001-01-01

    The neutron kinetic and the reactor dynamic behavior of Accelerator Driven Systems (ADS) is significantly different from those of conventional power reactor systems currently in use for the production of power. It is the objective of this study to examine and to demonstrate the intrinsic differences of the kinetic and dynamic behavior of accelerator driven systems to typical plant transient initiators in comparison to the known, kinetic and dynamic behavior of critical thermal and fast reactor systems. It will be shown that in sub-critical assemblies, changes in reactivity or in the external neutron source strength lead to an asymptotic power level essentially described by the instantaneous power change (i.e. prompt jump). Shutdown of ADS operating at high levels of sub-criticality, (i.e. k eff ∼0.99), without the support of reactivity control systems (such as control or safety rods), may be problematic in case the ability of cooling of the core should be impaired (i.e. loss of coolant flow). In addition, the dynamic behavior of sub-critical systems to typical plant transients such as protected or unprotected loss of flow (LOF) or heat sink (LOH) transients are not necessarily substantially different from the plant dynamic behavior of critical systems if the reactivity feedback coefficients of the ADS design are unfavorable. As expected, the state of sub-criticality and the temperature feedback coefficients, such as Doppler and coolant temperature coefficient, play dominant roles in determining the course and direction of plant transients. Should the combination of these safety coefficients be very unfavorable, not much additional margin in safety may be gained by making a critical system only sub-critical (i.e. k eff ∼0.95). A careful optimization procedure between the selected operating level of sub-criticality, the safety reactivity coefficients and the possible need for additional reactivity control systems seems, therefore, advisable during the early

  5. Progress report of the critical equipment monitoring system

    International Nuclear Information System (INIS)

    Pantis, M.J.

    1984-01-01

    The Philadelphia Electric Company has contracted with Energy Data Systems to develop a Critical Equipment Monitoring System for its Peach Bottom Nuclear Plant. This computerized system is designed to acquire and maintain accurate and timely status information on plant equipment. It will provide auditable record of plant and equipment transactions. Positive equipment identification and location will be provided. Errors in complex logical checking will be minimized. This system should reduce operator loading and improve operator communicatin with the plant personnel. Phase I of this system was installed at Peach Bottom Nuclear Station May 1982. It provides the necessary hardware and software to do check-off lists on critical plant systems. This paper describes some of the start-up and operational problems encountered

  6. Specialized computer system to diagnose critical lined equipment

    Science.gov (United States)

    Yemelyanov, V. A.; Yemelyanova, N. Y.; Morozova, O. A.; Nedelkin, A. A.

    2018-05-01

    The paper presents data on the problem of diagnosing the lining condition at the iron and steel works. The authors propose and describe the structure of the specialized computer system to diagnose critical lined equipment. The relative results of diagnosing lining condition by the basic system and the proposed specialized computer system are presented. To automate evaluation of lining condition and support in making decisions regarding the operation mode of the lined equipment, the specialized software has been developed.

  7. Criticality safety validation: Simple geometry, single unit 233U systems

    International Nuclear Information System (INIS)

    Putman, V.L.

    1997-06-01

    Typically used LMITCO criticality safety computational methods are evaluated for suitability when applied to INEEL 233 U systems which reasonably can be modeled as simple-geometry, single-unit systems. Sixty-seven critical experiments of uranium highly enriched in 233 U, including 57 aqueous solution, thermal-energy systems and 10 metal, fast-energy systems, were modeled. These experiments include 41 cylindrical and 26 spherical cores, and 41 reflected and 26 unreflected systems. No experiments were found for intermediate-neutron-energy ranges, or with interstitial non-hydrogenous materials typical of waste systems, mixed 233 U and plutonium, or reflectors such as steel, lead, or concrete. No simple geometry experiments were found with cubic or annular cores, or approximating infinite sea systems. Calculations were performed with various tools and methodologies. Nine cross-section libraries, based on ENDF/B-IV, -V, or -VI.2, or on Hansen-Roach source data, were used with cross-section processing methods of MCNP or SCALE. The k eff calculations were performed with neutral-particle transport and Monte Carlo methods of criticality codes DANT, MCNP 4A, and KENO Va

  8. Battery-Aware Scheduling of Mixed Criticality Systems

    DEFF Research Database (Denmark)

    Wognsen, Erik Ramsgaard; Hansen, Rene Rydhof; Larsen, Kim Guldstrand

    2014-01-01

    . Mixed criticality and soft real-time systems may accept deadline violations and therefore enable trade-offs and evaluation of performance by criteria such as the number of tasks that can be completed with a given battery. We model a task set in combination with the kinetic battery model as a stochastic...

  9. Bolted Flanged Connection for Critical Plant/Piping Systems

    International Nuclear Information System (INIS)

    Efremov, Anatoly

    2006-01-01

    A novel type of Bolted Flanged Connection with bolts and gasket manufactured on a basis of advanced Shape Memory Alloys is examined. Presented approach combined with inverse flexion flange design of plant/piping joint reveals a significant increase of internal pressure under conditions of a variety of operating temperatures relating to critical plant/piping systems. (author)

  10. The commons from a critical social systems perspective

    Directory of Open Access Journals (Sweden)

    Wolfgang Hofkirchner

    2014-04-01

    Full Text Available Normal 0 21 false false false IT JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:DE; mso-fareast-language:EN-US;} When developing the so-called Salzburg Approach to Information and Communication Technologies (ICTs and Society in the years 2004 to 2010, the sociology of technology the then working group of mine at the University of Salzburg used was based upon a combination of critical thinking and systems thinking – of Critical Theory and Systems Theory. Criticism and systemism both include what I’m used to calling the Logic of the Third. The Logic of the Third is the foundation of a critical social systems theory.  

  11. Disease scoring systems for oral lichen planus; a critical appraisal

    NARCIS (Netherlands)

    Wang, J.; van der Waal, I.

    2015-01-01

    The aim of the present study has been to critically review 22 disease scoring systems (DSSs) on oral lichen planus (OLP) that have been reported in the literature during the past decades. Although the presently available DSSs may all have some merit, particularly for research purposes, the diversity

  12. 'One physical system': Tansley's ecosystem as Earth's critical zone.

    Science.gov (United States)

    Richter, Daniel deB; Billings, Sharon A

    2015-05-01

    Integrative concepts of the biosphere, ecosystem, biogeocenosis and, recently, Earth's critical zone embrace scientific disciplines that link matter, energy and organisms in a systems-level understanding of our remarkable planet. Here, we assert the congruence of Tansley's (1935) venerable ecosystem concept of 'one physical system' with Earth science's critical zone. Ecosystems and critical zones are congruent across spatial-temporal scales from vegetation-clad weathering profiles and hillslopes, small catchments, landscapes, river basins, continents, to Earth's whole terrestrial surface. What may be less obvious is congruence in the vertical dimension. We use ecosystem metabolism to argue that full accounting of photosynthetically fixed carbon includes respiratory CO₂ and carbonic acid that propagate to the base of the critical zone itself. Although a small fraction of respiration, the downward diffusion of CO₂ helps determine rates of soil formation and, ultimately, ecosystem evolution and resilience. Because life in the upper portions of terrestrial ecosystems significantly affects biogeochemistry throughout weathering profiles, the lower boundaries of most terrestrial ecosystems have been demarcated at depths too shallow to permit a complete understanding of ecosystem structure and function. Opportunities abound to explore connections between upper and lower components of critical-zone ecosystems, between soils and streams in watersheds, and between plant-derived CO₂ and deep microbial communities and mineral weathering. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  13. SUPERCOMPUTER SIMULATION OF CRITICAL PHENOMENA IN COMPLEX SOCIAL SYSTEMS

    Directory of Open Access Journals (Sweden)

    Petrus M.A. Sloot

    2014-09-01

    Full Text Available The paper describes a problem of computer simulation of critical phenomena in complex social systems on a petascale computing systems in frames of complex networks approach. The three-layer system of nested models of complex networks is proposed including aggregated analytical model to identify critical phenomena, detailed model of individualized network dynamics and model to adjust a topological structure of a complex network. The scalable parallel algorithm covering all layers of complex networks simulation is proposed. Performance of the algorithm is studied on different supercomputing systems. The issues of software and information infrastructure of complex networks simulation are discussed including organization of distributed calculations, crawling the data in social networks and results visualization. The applications of developed methods and technologies are considered including simulation of criminal networks disruption, fast rumors spreading in social networks, evolution of financial networks and epidemics spreading.

  14. Energy dependence of critical state of single-component systems

    International Nuclear Information System (INIS)

    Volchenkova, R.A.

    1985-01-01

    Equations of critical states of the single-component systems: Psub(cr)(/Psub(o)=(Tsub(cr)/Tsub(o))x0.73, Tsub(cr)=K(Tsub(boil))sup(1.116) and Hsub(cr)(/Hsub(B)=Tsub(sr)/Tsub(B))sup(1.48) where Tsub(B)=1K, Hsub(B)-2 kcal/g-at, K-dimension factor are presented. It is shown that the revealed dependence Hsub(cr)=H(Tsub(cr)) is an energy boundary of a liquid-vapour phase state of the single-component systems beyond limits of which difference between liquid and vapour phases vanishes in increasing the system energy content. The given equations of state are true for all the single-component systems and permit to consider physicomechanical properties of substances in dynamic state depending on external conditions. Critical temperatures and dependences for elements from the most fusible He to infusible W and Re have been calculated

  15. Application of SAE ARP4754A to Flight Critical Systems

    Science.gov (United States)

    Peterson, Eric M.

    2015-01-01

    This report documents applications of ARP4754A to the development of modern computer-based (i.e., digital electronics, software and network-based) aircraft systems. This study is to offer insight and provide educational value relative to the guidelines in ARP4754A and provide an assessment of the current state-of-the- practice within industry and regulatory bodies relative to development assurance for complex and safety-critical computer-based aircraft systems.

  16. Seminar in Critical Inquiry Twenty-first Century Nuclear Systems

    Energy Technology Data Exchange (ETDEWEB)

    LeMone, D. V.

    2002-02-25

    Critical Inquiry, has not only been successful in increasing university student retention rate but also in improving student academic performance beyond the initial year of transition into the University. The seminar course herein reviewed is a balanced combination of student personal and academic skill development combined with a solid background in modern nuclear systems. It is a valid premise to assume that entering students as well as stakeholders of the general public demonstrate equal levels of capability. Nuclear systems is designed to give a broad and basic knowledge of nuclear power, medical, industrial, research, and military systems (nuclear systems) in 20-25 hours.

  17. Seminar in Critical Inquiry Twenty-first Century Nuclear Systems

    International Nuclear Information System (INIS)

    LeMone, D. V.

    2002-01-01

    Critical Inquiry, has not only been successful in increasing university student retention rate but also in improving student academic performance beyond the initial year of transition into the University. The seminar course herein reviewed is a balanced combination of student personal and academic skill development combined with a solid background in modern nuclear systems. It is a valid premise to assume that entering students as well as stakeholders of the general public demonstrate equal levels of capability. Nuclear systems is designed to give a broad and basic knowledge of nuclear power, medical, industrial, research, and military systems (nuclear systems) in 20-25 hours

  18. The theory of critical phenomena in two-dimensional systems

    International Nuclear Information System (INIS)

    Olvera de la C, M.

    1981-01-01

    An exposition of the theory of critical phenomena in two-dimensional physical systems is presented. The first six chapters deal with the mean field theory of critical phenomena, scale invariance of the thermodynamic functions, Kadanoff's spin block construction, Wilson's renormalization group treatment of critical phenomena in configuration space, and the two-dimensional Ising model on a triangular lattice. The second part of this work is made of four chapters devoted to the application of the ideas expounded in the first part to the discussion of critical phenomena in superfluid films, two-dimensional crystals and the two-dimensional XY model of magnetic systems. Chapters seven to ten are devoted to the following subjects: analysis of long range order in one, two, and three-dimensional physical systems. Topological defects in the XY model, in superfluid films and in two-dimensional crystals. The Thouless-Kosterlitz iterated mean field theory of the dipole gas. The renormalization group treatment of the XY model, superfluid films and two-dimensional crystal. (author)

  19. Neural Network Based Intrusion Detection System for Critical Infrastructures

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Ondrej Linda; Milos Manic

    2009-07-01

    Resiliency and security in control systems such as SCADA and Nuclear plant’s in today’s world of hackers and malware are a relevant concern. Computer systems used within critical infrastructures to control physical functions are not immune to the threat of cyber attacks and may be potentially vulnerable. Tailoring an intrusion detection system to the specifics of critical infrastructures can significantly improve the security of such systems. The IDS-NNM – Intrusion Detection System using Neural Network based Modeling, is presented in this paper. The main contributions of this work are: 1) the use and analyses of real network data (data recorded from an existing critical infrastructure); 2) the development of a specific window based feature extraction technique; 3) the construction of training dataset using randomly generated intrusion vectors; 4) the use of a combination of two neural network learning algorithms – the Error-Back Propagation and Levenberg-Marquardt, for normal behavior modeling. The presented algorithm was evaluated on previously unseen network data. The IDS-NNM algorithm proved to be capable of capturing all intrusion attempts presented in the network communication while not generating any false alerts.

  20. A criticism of ANSI/ANS-8.3-1986: Criticality accident alarm system

    International Nuclear Information System (INIS)

    Malenfant, R.E.

    1991-01-01

    The American National Standard on criticality accident alarm systems has given rise to confusion in interpretation and implementation of the requirements. In addition, some of the standards have recently been incorporated into US Department of Energy (DOE) orders, and others have been paraphrased in the DOE orders. Some of the DOE orders referencing these standards are being incorporated into law by means of the Code of Federal Regulations. As such, the intent of the authors of the standards to recommend a code of good practice is now being codified into law with attendant civil and criminal penalties for failure to comply. It is suggested that ANSI/ANS-8.3-1986, Critically Accident Alarm System, be carefully reviewed to alleviate the confusion that has been experienced in practice, to clarify the minimum accident of concern, to further define the dose (or dose rate) criteria for activation, and to stress the fact that a prime consideration in any safety system is the overall reduction of risk

  1. Description of Fracture Systems for External Criticality Reports

    International Nuclear Information System (INIS)

    Nicot, Jean-Philippe

    2001-01-01

    The purpose of this Analysis/Model Report (AMR) is to describe probabilistically the main features of the geometry of the fracture system in the vicinity of the repository. They will be used to determine the quantity of fissile material that could accumulate in the fractured rock underneath a waste package as it degrades. This AMR is to feed the geochemical calculations for external criticality reports. This AMR is done in accordance with the technical work plan (BSC (Bechtel SAIC Company) 2001 b). The scope of this AMR is restricted to the relevant parameters of the fracture system. The main parameters of interest are fracture aperture and fracture spacing distribution parameters. The relative orientation of the different fracture sets is also important because of its impact on criticality, but they will be set deterministically. The maximum accumulation of material depends primarily on the fracture porosity, combination of the fracture aperture, and fracture intensity. However, the fracture porosity itself is not sufficient to characterize the potential for accumulation of a fracture system. The fracture aperture is also important because it controls both the flow through the fracture and the potential plugging of the system. Other features contributing to the void space such as lithophysae are also investigated. On the other hand, no analysis of the matrix porosity is done. The parameters will be used in sensitivity analyses of geochemical calculations providing actinide accumulations and in the subsequent Monte Carlo criticality analyses

  2. Architecture Level Safety Analyses for Safety-Critical Systems

    Directory of Open Access Journals (Sweden)

    K. S. Kushal

    2017-01-01

    Full Text Available The dependency of complex embedded Safety-Critical Systems across Avionics and Aerospace domains on their underlying software and hardware components has gradually increased with progression in time. Such application domain systems are developed based on a complex integrated architecture, which is modular in nature. Engineering practices assured with system safety standards to manage the failure, faulty, and unsafe operational conditions are very much necessary. System safety analyses involve the analysis of complex software architecture of the system, a major aspect in leading to fatal consequences in the behaviour of Safety-Critical Systems, and provide high reliability and dependability factors during their development. In this paper, we propose an architecture fault modeling and the safety analyses approach that will aid in identifying and eliminating the design flaws. The formal foundations of SAE Architecture Analysis & Design Language (AADL augmented with the Error Model Annex (EMV are discussed. The fault propagation, failure behaviour, and the composite behaviour of the design flaws/failures are considered for architecture safety analysis. The illustration of the proposed approach is validated by implementing the Speed Control Unit of Power-Boat Autopilot (PBA system. The Error Model Annex (EMV is guided with the pattern of consideration and inclusion of probable failure scenarios and propagation of fault conditions in the Speed Control Unit of Power-Boat Autopilot (PBA. This helps in validating the system architecture with the detection of the error event in the model and its impact in the operational environment. This also provides an insight of the certification impact that these exceptional conditions pose at various criticality levels and design assurance levels and its implications in verifying and validating the designs.

  3. Software Safety Risk in Legacy Safety-Critical Computer Systems

    Science.gov (United States)

    Hill, Janice L.; Baggs, Rhoda

    2007-01-01

    Safety Standards contain technical and process-oriented safety requirements. Technical requirements are those such as "must work" and "must not work" functions in the system. Process-Oriented requirements are software engineering and safety management process requirements. Address the system perspective and some cover just software in the system > NASA-STD-8719.13B Software Safety Standard is the current standard of interest. NASA programs/projects will have their own set of safety requirements derived from the standard. Safety Cases: a) Documented demonstration that a system complies with the specified safety requirements. b) Evidence is gathered on the integrity of the system and put forward as an argued case. [Gardener (ed.)] c) Problems occur when trying to meet safety standards, and thus make retrospective safety cases, in legacy safety-critical computer systems.

  4. Software Reliability Issues Concerning Large and Safety Critical Software Systems

    Science.gov (United States)

    Kamel, Khaled; Brown, Barbara

    1996-01-01

    This research was undertaken to provide NASA with a survey of state-of-the-art techniques using in industrial and academia to provide safe, reliable, and maintainable software to drive large systems. Such systems must match the complexity and strict safety requirements of NASA's shuttle system. In particular, the Launch Processing System (LPS) is being considered for replacement. The LPS is responsible for monitoring and commanding the shuttle during test, repair, and launch phases. NASA built this system in the 1970's using mostly hardware techniques to provide for increased reliability, but it did so often using custom-built equipment, which has not been able to keep up with current technologies. This report surveys the major techniques used in industry and academia to ensure reliability in large and critical computer systems.

  5. The under-critical reactors physics for the hybrid systems

    International Nuclear Information System (INIS)

    Schapira, J.P.; Vergnes, J.; Zaetta, A.

    1998-01-01

    This day, organized by the SFEN, took place at Paris the 12 march 1998. Nine papers were presented. They take stock on the hybrid systems and more specifically the under-critical reactors. One of the major current preoccupation of nuclear industry is the problems of the increase of radioactive wastes produced in the plants and the destruction of the present stocks. To solve these problems a solution is the utilisation of hybrid systems: the coupling of a particle acceleration to an under-critical reactor. Historical aspects, advantages and performances of such hybrid reactors are presented in general papers. More technical papers are devoted to the spallation, the MUSE and the TARC experiments. (A.L.B.)

  6. Emerging and Future Cyber Threats to Critical Systems

    OpenAIRE

    Djambazova , Edita; Almgren , Magnus; Dimitrov , Kiril; Jonsson , Erland

    2010-01-01

    Part 2: Adversaries; International audience; This paper discusses the emerging and future cyber threats to critical systems identified during the EU/FP7 project ICT-FORWARD. Threats were identified after extensive discussions with both domain experts and IT security professionals from academia, industry, and government organizations. The ultimate goal of the work was to identify the areas in which cyber threats could occur and cause serious and undesirable consequences, based on the character...

  7. Recent and proposed changes in criticality alarm system requirements

    International Nuclear Information System (INIS)

    Putman, V.L.

    1998-01-01

    Various changes in criticality alarm system (CAS) requirements of American Nuclear Society (ANS) standards, US Department of Energy (DOE) orders, US Nuclear Regulatory Commission (NRC) regulations and guidance, and Occupational Safety and Health Administration (OSHA) standards or regulations were approved or proposed in the last 5 yr. Many changes interpreted or clarified existing requirements or accommodated technological or organizational developments. However, some changes could substantively affect CAS programs, including several changes originally thought to be editorial. These changes are discussed here

  8. Spacecraft System Integration and Test: SSTI Lewis critical design audit

    Science.gov (United States)

    Brooks, R. P.; Cha, K. K.

    1995-01-01

    The Critical Design Audit package is the final detailed design package which provides a comprehensive description of the SSTI mission. This package includes the program overview, the system requirements, the science and applications activities, the ground segment development, the assembly, integration and test description, the payload and technology demonstrations, and the spacecraft bus subsystems. Publication and presentation of this document marks the final requirements and design freeze for SSTI.

  9. Universality classes and critical phenomena in confined liquid systems

    Directory of Open Access Journals (Sweden)

    A.V. Chalyi

    2013-06-01

    Full Text Available It is well known that the similar universal behavior of infinite-size (bulk systems of different nature requires the same basic conditions: space dimensionality; number components of order parameter; the type (short- or long-range of the intermolecular interaction; symmetry of the fluctuation part of thermodynamical potential. Basic conditions of similar universal behavior of confined systems needs the same supplementary conditions such as the number of monolayers for a system confinement; low crossover dimensionality, i.e., geometric form of restricted volume; boundary conditions on limiting surfaces; physical properties under consideration. This review paper is aimed at studying all these conditions of similar universal behavior for diffusion processes in confined liquid systems. Special attention was paid to the effects of spatial dispersion and low crossover dimensionality. This allowed us to receive receiving correct nonzero expressions for the diffusion coefficient at the critical point and to take into account the specific geometric form of the confined liquid volume. The problem of 3D⇔2D dimensional crossover was analyzed. To receive a smooth crossover for critical exponents, the Kawasaki-like approach from the theory of mode coupling in critical dynamics was proposed. This ensured a good agreement between data of computer experiment and theoretical calculations of the size dependence of the critical temperature Tc(H of water in slitlike pores. The width of the quasi-elastic scattering peak of slow neutrons near the structural phase transition in the aquatic suspensions of plasmatic membranes (mesostructures with the typical thickness up to 10 nm was studied. It was shown that the width of quasi-elastic peak of neutron scattering decreases due to the process of cell proliferation, i.e., with an increase of the membrane size (including the membrane thickness. Thus, neutron studies could serve as an additional diagnostic test for the

  10. Protecting Commercial Space Systems: A Critical National Security Issue

    Science.gov (United States)

    1999-04-01

    systems. Part two will describe, at the operational level , this author’s theory for space protection and recommend a course of action to work...minimal loss of life. These factors force us to conclude this is a critical national security issue just as many in high- level government positions...Command and Staff College Operational Forces Coursebook (Academic Year 1999), 35. 3 The USCG is not a Title 10 Service, thus Posse Comitatus is not a

  11. Systems Engineering-Based Tool for Identifying Critical Research Systems

    Science.gov (United States)

    Abbott, Rodman P.; Stracener, Jerrell

    2016-01-01

    This study investigates the relationship between the designated research project system independent variables of Labor, Travel, Equipment, and Contract total annual costs and the dependent variables of both the associated matching research project total annual academic publication output and thesis/dissertation number output. The Mahalanobis…

  12. Critical interfaces in geosynthetic multilayer liner system of a landfill

    Directory of Open Access Journals (Sweden)

    Qian Xuede

    2008-12-01

    Full Text Available This study is to identify the critical interface in a geosynthetic multilayer liner system by examining the effects of the interface shear strength of liner components, leachate level, leachate buildup cases, and peak and residual interface strengths. According to current landfill design procedures, conducting stability analysis along the same interface at both the back slope and base may result in a non-conservative result. The critical interfaces with the minimum factor of safety are generally found at different locations along the back slope and base. The critical interface for a multilayer liner system cannot simply be assumed during stability analysis. It can shift from one interface to another with changes in the leachate level and with different leachate buildup cases. The factor of safety for an interface with a high friction angle and low apparent cohesion generally drops much more quickly than it does under inverse conditions when the leachate level increases. The failure interface in a liner system under residual conditions is usually different from the failure interface under peak conditions.

  13. Analyzing Software Requirements Errors in Safety-Critical, Embedded Systems

    Science.gov (United States)

    Lutz, Robyn R.

    1993-01-01

    This paper analyzes the root causes of safety-related software errors in safety-critical, embedded systems. The results show that software errors identified as potentially hazardous to the system tend to be produced by different error mechanisms than non- safety-related software errors. Safety-related software errors are shown to arise most commonly from (1) discrepancies between the documented requirements specifications and the requirements needed for correct functioning of the system and (2) misunderstandings of the software's interface with the rest of the system. The paper uses these results to identify methods by which requirements errors can be prevented. The goal is to reduce safety-related software errors and to enhance the safety of complex, embedded systems.

  14. Disease scoring systems for oral lichen planus; a critical appraisal

    Science.gov (United States)

    Wang, Jing

    2015-01-01

    The aim of the present study has been to critically review 22 disease scoring systems (DSSs) on oral lichen planus (OLP) that have been reported in the literature during the past decades. Although the presently available DSSs may all have some merit, particularly for research purposes, the diversity of both the objective and subjective parameters used in these systems and the lack of acceptance of one of these systems for uniform use, there is a need for an international, authorized consensus meeting on this subject. Because of the natural course of OLP characterized by remissions and exacerbations and also due to the varying distribution pattern and the varying clinical types, e.g. reticular and erosive, the relevance of a DSS based on morphologic parameters is somewhat questionable. Instead, one may consider to only look for a quality of life scoring system adapted for use in OLP patients. Key words:Oral lichen planus, disease scoring system, classification. PMID:25681372

  15. Bowel management systems in critical care: a service evaluation.

    Science.gov (United States)

    Ritzema, Jennifer

    2017-01-25

    Aim Many patients who are critically ill develop faecal incontinence associated with diarrhoea, and require a bowel management system (BMS) to prevent skin excoriation. Following guidelines produced by the National Institute for Health and Care Excellence, early rehabilitation has resulted in a reduction in the number of days that patients receive mechanical ventilation. However, patients with a BMS are potentially mechanically ventilated for longer because they are cared for in bed. The aim of this evaluation was to investigate whether patients with a BMS are mechanically ventilated for longer than those without a BMS. Method This was a retrospective service evaluation, in which a database search was conducted to identify patients admitted to the critical care department in one healthcare organisation during 2013. The search was narrowed to identify patients admitted to the critical care department who had received advanced respiratory support (mechanical ventilation), to compare the mean number of mechanically ventilated days between patients with and without a BMS (n = 122). Data were analysed using the Mann-Whitney U test. Results There was a significant difference in the number of mechanically ventilated days (Pcritically ill patients with a BMS are placed in a sitting position for short periods of time. Further research should explore alternative bowel care options for patients who are critically ill.

  16. On self-organized criticality in nonconserving systems

    International Nuclear Information System (INIS)

    Socolar, J.E.S.; Grinstein, G.; Jayaprakash, C.

    1993-01-01

    Two models with nonconserving dynamics and slow continuous deterministic driving, a stick-slip model (SSM) of earthquake dynamics and a toy forest-fire model (FFM), have recently been argued to show numerical evidence of self-organized criticality (generic, scale-invariant steady states). To determine whether the observed criticality is indeed generic, we study these models as a function of a parameter γ which was implicitly tuned to a special value, γ=1, in their original definitions. In both cases, the maximum Lyapunov exponent vanishes at γ=1. We find that the FFM does not exhibit self-organized criticality for any γ, including γ=1; nor does the SSM with periodic boundary conditions. Both models show evidence of macroscopic periodic oscillations in time for some range of γ values. We suggest that such oscillations may provide a mechanism for the generation of scale-invariant structure in nonconserving systems, and, in particular, that they underlie the criticality previously observed in the SSM with open boundary conditions

  17. Evaluating Models of Human Performance: Safety-Critical Systems Applications

    Science.gov (United States)

    Feary, Michael S.

    2012-01-01

    This presentation is part of panel discussion on Evaluating Models of Human Performance. The purpose of this panel is to discuss the increasing use of models in the world today and specifically focus on how to describe and evaluate models of human performance. My presentation will focus on discussions of generating distributions of performance, and the evaluation of different strategies for humans performing tasks with mixed initiative (Human-Automation) systems. I will also discuss issues with how to provide Human Performance modeling data to support decisions on acceptability and tradeoffs in the design of safety critical systems. I will conclude with challenges for the future.

  18. Verification and Validation for Flight-Critical Systems (VVFCS)

    Science.gov (United States)

    Graves, Sharon S.; Jacobsen, Robert A.

    2010-01-01

    On March 31, 2009 a Request for Information (RFI) was issued by NASA s Aviation Safety Program to gather input on the subject of Verification and Validation (V & V) of Flight-Critical Systems. The responses were provided to NASA on or before April 24, 2009. The RFI asked for comments in three topic areas: Modeling and Validation of New Concepts for Vehicles and Operations; Verification of Complex Integrated and Distributed Systems; and Software Safety Assurance. There were a total of 34 responses to the RFI, representing a cross-section of academic (26%), small & large industry (47%) and government agency (27%).

  19. Review on modeling and simulation of interdependent critical infrastructure systems

    International Nuclear Information System (INIS)

    Ouyang, Min

    2014-01-01

    Modern societies are becoming increasingly dependent on critical infrastructure systems (CISs) to provide essential services that support economic prosperity, governance, and quality of life. These systems are not alone but interdependent at multiple levels to enhance their overall performance. However, recent worldwide events such as the 9/11 terrorist attack, Gulf Coast hurricanes, the Chile and Japanese earthquakes, and even heat waves have highlighted that interdependencies among CISs increase the potential for cascading failures and amplify the impact of both large and small scale initial failures into events of catastrophic proportions. To better understand CISs to support planning, maintenance and emergency decision making, modeling and simulation of interdependencies across CISs has recently become a key field of study. This paper reviews the studies in the field and broadly groups the existing modeling and simulation approaches into six types: empirical approaches, agent based approaches, system dynamics based approaches, economic theory based approaches, network based approaches, and others. Different studies for each type of the approaches are categorized and reviewed in terms of fundamental principles, such as research focus, modeling rationale, and the analysis method, while different types of approaches are further compared according to several criteria, such as the notion of resilience. Finally, this paper offers future research directions and identifies critical challenges in the field. - Highlights: • Modeling approaches on interdependent critical infrastructure systems are reviewed. • I mainly review empirical, agent-based, system-dynamics, economic, network approaches. • Studies by each approach are sorted out in terms of fundamental principles. • Different approaches are further compared with resilience as the main criterion

  20. Towards a lessons learned system for critical software

    International Nuclear Information System (INIS)

    Andrade, J.; Ares, J.; Garcia, R.; Pazos, J.; Rodriguez, S.; Rodriguez-Paton, A.; Silva, A.

    2007-01-01

    Failure can be a major driver for the advance of any engineering discipline and Software Engineering is no exception. But failures are useful only if lessons are learned from them. In this article we aim to make a strong defence of, and set the requirements for, lessons learned systems for safety-critical software. We also present a prototype lessons learned system that includes many of the features discussed here. We emphasize that, apart from individual organizations, lessons learned systems should target industrial sectors and even the Software Engineering community. We would like to encourage the Software Engineering community to use this kind of systems as another tool in the toolbox, which complements or enhances other approaches like, for example, standards and checklists

  1. Towards a lessons learned system for critical software

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, J. [University of A Coruna. Campus de Elvina, s/n. 15071, A Coruna (Spain)]. E-mail: jag@udc.es; Ares, J. [University of A Coruna. Campus de Elvina, s/n. 15071, A Coruna (Spain)]. E-mail: juanar@udc.es; Garcia, R. [University of A Coruna. Campus de Elvina, s/n. 15071, A Coruna (Spain)]. E-mail: rafael@udc.es; Pazos, J. [Technical University of Madrid. Campus de Montegancedo, s/n. 28660, Boadilla del Monte, Madrid (Spain)]. E-mail: jpazos@fi.upm.es; Rodriguez, S. [University of A Coruna. Campus de Elvina, s/n. 15071, A Coruna (Spain)]. E-mail: santi@udc.es; Rodriguez-Paton, A. [Technical University of Madrid. Campus de Montegancedo, s/n. 28660, Boadilla del Monte, Madrid (Spain)]. E-mail: arpaton@fi.upm.es; Silva, A. [Technical University of Madrid. Campus de Montegancedo, s/n. 28660, Boadilla del Monte, Madrid (Spain)]. E-mail: asilva@fi.upm.es

    2007-07-15

    Failure can be a major driver for the advance of any engineering discipline and Software Engineering is no exception. But failures are useful only if lessons are learned from them. In this article we aim to make a strong defence of, and set the requirements for, lessons learned systems for safety-critical software. We also present a prototype lessons learned system that includes many of the features discussed here. We emphasize that, apart from individual organizations, lessons learned systems should target industrial sectors and even the Software Engineering community. We would like to encourage the Software Engineering community to use this kind of systems as another tool in the toolbox, which complements or enhances other approaches like, for example, standards and checklists.

  2. Probabilistic DHP adaptive critic for nonlinear stochastic control systems.

    Science.gov (United States)

    Herzallah, Randa

    2013-06-01

    Following the recently developed algorithms for fully probabilistic control design for general dynamic stochastic systems (Herzallah & Káarnáy, 2011; Kárný, 1996), this paper presents the solution to the probabilistic dual heuristic programming (DHP) adaptive critic method (Herzallah & Káarnáy, 2011) and randomized control algorithm for stochastic nonlinear dynamical systems. The purpose of the randomized control input design is to make the joint probability density function of the closed loop system as close as possible to a predetermined ideal joint probability density function. This paper completes the previous work (Herzallah & Káarnáy, 2011; Kárný, 1996) by formulating and solving the fully probabilistic control design problem on the more general case of nonlinear stochastic discrete time systems. A simulated example is used to demonstrate the use of the algorithm and encouraging results have been obtained. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Diversity requirements for safety critical software-based automation systems

    International Nuclear Information System (INIS)

    Korhonen, J.; Pulkkinen, U.; Haapanen, P.

    1998-03-01

    System vendors nowadays propose software-based systems even for the most critical safety functions in nuclear power plants. Due to the nature and mechanisms of influence of software faults new methods are needed for the safety and reliability evaluation of these systems. In the research project 'Programmable automation systems in nuclear power plants (OHA)' various safety assessment methods and tools for software based systems are developed and evaluated. This report first discusses the (common cause) failure mechanisms in software-based systems, then defines fault-tolerant system architectures to avoid common cause failures, then studies the various alternatives to apply diversity and their influence on system reliability. Finally, a method for the assessment of diversity is described. Other recently published reports in OHA-report series handles the statistical reliability assessment of software based (STUK-YTO-TR 119), usage models in reliability assessment of software-based systems (STUK-YTO-TR 128) and handling of programmable automation in plant PSA-studies (STUK-YTO-TR 129)

  4. International conference on sub-critical accelerator driven systems. Proceedings

    International Nuclear Information System (INIS)

    Litovkina, L.P.; Titarenko, Yu.E.

    1999-01-01

    The International Meeting on Sub-Critical Accelerator Driven Systems was organized by the State Scientific Center - Institute for Theoretical and Experimental Physics with participation of Atomic Ministry of RF. The Meeting objective was to analyze the recent achievements and tendencies of the accelerator-driven systems development. The Meeting program covers a broad range of problems including the accelerator-driven systems (ADS) conceptual design; analyzing the ADS role in nuclear fuel cycle; accuracy of modeling the main parameters of ADS; conceptual design of high-current accelerators. Moreover, the results of recent experimental and theoretical studies on nuclear data accumulation to support the ADS technologies are presented. About 70 scientists from the main scientific centers of Russia, as well as scientists from USA, France, Belgium, India, and Yugoslavia, attended the meeting and presented 44 works [ru

  5. Information Retrieval and Criticality in Parity-Time-Symmetric Systems.

    Science.gov (United States)

    Kawabata, Kohei; Ashida, Yuto; Ueda, Masahito

    2017-11-10

    By investigating information flow between a general parity-time (PT-)symmetric non-Hermitian system and an environment, we find that the complete information retrieval from the environment can be achieved in the PT-unbroken phase, whereas no information can be retrieved in the PT-broken phase. The PT-transition point thus marks the reversible-irreversible criticality of information flow, around which many physical quantities such as the recurrence time and the distinguishability between quantum states exhibit power-law behavior. Moreover, by embedding a PT-symmetric system into a larger Hilbert space so that the entire system obeys unitary dynamics, we reveal that behind the information retrieval lies a hidden entangled partner protected by PT symmetry. Possible experimental situations are also discussed.

  6. Quantitative reliability assessment for safety critical system software

    International Nuclear Information System (INIS)

    Chung, Dae Won; Kwon, Soon Man

    2005-01-01

    An essential issue in the replacement of the old analogue I and C to computer-based digital systems in nuclear power plants is the quantitative software reliability assessment. Software reliability models have been successfully applied to many industrial applications, but have the unfortunate drawback of requiring data from which one can formulate a model. Software which is developed for safety critical applications is frequently unable to produce such data for at least two reasons. First, the software is frequently one-of-a-kind, and second, it rarely fails. Safety critical software is normally expected to pass every unit test producing precious little failure data. The basic premise of the rare events approach is that well-tested software does not fail under normal routine and input signals, which means that failures must be triggered by unusual input data and computer states. The failure data found under the reasonable testing cases and testing time for these conditions should be considered for the quantitative reliability assessment. We will present the quantitative reliability assessment methodology of safety critical software for rare failure cases in this paper

  7. A Study on the Planning of Technology Development and Research for Generation IV Nuclear Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Moon Hee; Kim, H. R.; Kim, H. J. and others

    2005-08-15

    This study aimed at the planning the domestic technology development of the Gen IV and the formulating the international collaborative project contents and executive plan for 'A Validity Assessment and Policies of the R and D of Generation IV Nuclear Energy Systems'. The results of the study include follows; - Survey of the technology state in the fields of the Gen IV system specific technologies and the common technologies, and the plans of the international collaborative research - Drawing up the executive research and development plan by the experts of the relevant technology field for the systems which Korean will participate in. - Formulating the effective conduction plan of the program reflecting the view of the experts from the industry, the university and the research institute. - Establishing the plan for estimation of the research fund and the manpower for the efficient utilization of the domestic available resources. This study can be useful material for evaluating the appropriateness of the Korea's participation in the international collaborative development of the Gen IV, and can be valuably utilized to establish the strategy for the effective conduction of the program. The executive plan of the research and development which was produced in this study will be used to the basic materials for the establishing the guiding direction and the strategic conduction of the program when the research and development is launched in the future.

  8. Using event-B for critical device software systems

    CERN Document Server

    Singh, Neeraj Kumar

    2013-01-01

    Defining a new development life-cycle methodology, together with a set of associated techniques and tools to develop highly critical systems using formal techniques, this book adopts a rigorous safety assessment approach explored via several layers (from requirements analysis to automatic source code generation). This is assessed and evaluated via a standard case study: the cardiac pacemaker. Additionally a formalisation of an Electrocardiogram (ECG) is used to identify anomalies in order to improve existing medical protocols. This allows the key issue - that formal methods are not currently i

  9. Reliability assessment for safety critical systems by statistical random testing

    International Nuclear Information System (INIS)

    Mills, S.E.

    1995-11-01

    In this report we present an overview of reliability assessment for software and focus on some basic aspects of assessing reliability for safety critical systems by statistical random testing. We also discuss possible deviations from some essential assumptions on which the general methodology is based. These deviations appear quite likely in practical applications. We present and discuss possible remedies and adjustments and then undertake applying this methodology to a portion of the SDS1 software. We also indicate shortcomings of the methodology and possible avenues to address to follow to address these problems. (author). 128 refs., 11 tabs., 31 figs

  10. Reliability assessment for safety critical systems by statistical random testing

    Energy Technology Data Exchange (ETDEWEB)

    Mills, S E [Carleton Univ., Ottawa, ON (Canada). Statistical Consulting Centre

    1995-11-01

    In this report we present an overview of reliability assessment for software and focus on some basic aspects of assessing reliability for safety critical systems by statistical random testing. We also discuss possible deviations from some essential assumptions on which the general methodology is based. These deviations appear quite likely in practical applications. We present and discuss possible remedies and adjustments and then undertake applying this methodology to a portion of the SDS1 software. We also indicate shortcomings of the methodology and possible avenues to address to follow to address these problems. (author). 128 refs., 11 tabs., 31 figs.

  11. Critical Technologies for the Development of Future Space Elevator Systems

    Science.gov (United States)

    Smitherman, David V., Jr.

    2005-01-01

    A space elevator is a tether structure extending through geosynchronous earth orbit (GEO) to the surface of the earth. Its center of mass is in GEO such that it orbits the earth in sync with the earth s rotation. In 2004 and 2005, the NASA Marshall Space Flight Center and the Institute for Scientific Research, Inc. worked under a cooperative agreement to research the feasibility of space elevator systems, and to advance the critical technologies required for the future development of space elevators for earth to orbit transportation. The discovery of carbon nanotubes in the early 1990's was the first indication that it might be possible to develop materials strong enough to make space elevator construction feasible. This report presents an overview of some of the latest NASA sponsored research on space elevator design, and the systems and materials that will be required to make space elevator construction possible. In conclusion, the most critical technology for earth-based space elevators is the successful development of ultra high strength carbon nanotube reinforced composites for ribbon construction in the 1OOGPa range. In addition, many intermediate technology goals and demonstration missions for the space elevator can provide significant advancements to other spaceflight and terrestrial applications.

  12. A Study on planning of promotion for international collaborative development of Generation IV Nuclear Energy Systems

    International Nuclear Information System (INIS)

    Hee, Chang Moon; Yang, M. S.; Ha, J. J.

    2006-06-01

    Korea has participated in the international collaboration programs for the development of future nuclear energy systems driven by the countries holding advanced nuclear technology and Korea and U. S. have cooperated in the INERI. This study is mainly at developing the plan for participation in the collaborative development of the Gen IV, searching the participation strategy for INERI and the INPRO, and the international cooperation in these programs. Contents and scope of the study for successful achievement are as follows; - Investigation and analysis of international and domestic trends related to advanced nuclear technologies - Development of the plan for collaborative development of the Gen IV and conducting the international cooperation activities - Support for the activities related to I-NERI between Korea and U. S. and conducting the international cooperation - International cooperation activities for the INPRO This study can be useful for planning the research plan and setting up of the strategy of integrating the results of the international collaboration and the domestic R and D results by combining the Gen IV and the domestic R and D in the field of future nuclear technology. Furthermore, this study can contribute to establishing the effective foundation and broadening the cooperation activities not only with the advanced countries for acquisition of the advanced technologies but also with the developing countries for the export of the domestic nuclear energy systems

  13. FEATURES, EVENTS, AND PROCESSES: SYSTEM-LEVEL AND CRITICALITY

    International Nuclear Information System (INIS)

    D.L. McGregor

    2000-01-01

    The primary purpose of this Analysis/Model Report (AMR) is to identify and document the screening analyses for the features, events, and processes (FEPs) that do not easily fit into the existing Process Model Report (PMR) structure. These FEPs include the 3 1 FEPs designated as System-Level Primary FEPs and the 22 FEPs designated as Criticality Primary FEPs. A list of these FEPs is provided in Section 1.1. This AMR (AN-WIS-MD-000019) documents the Screening Decision and Regulatory Basis, Screening Argument, and Total System Performance Assessment (TSPA) Disposition for each of the subject Primary FEPs. This AMR provides screening information and decisions for the TSPA-SR report and provides the same information for incorporation into a project-specific FEPs database. This AMR may also assist reviewers during the licensing-review process

  14. Use of modern software - based instrumentation in safety critical systems

    International Nuclear Information System (INIS)

    Emmett, J.; Smith, B.

    2005-01-01

    Many Nuclear Power Plants are now ageing and in need of various degrees of refurbishment. Installed instrumentation usually uses out of date 'analogue' technology and is often no longer available in the market place. New technology instrumentation is generally un-qualified for nuclear use and specifically the new 'smart' technology contains 'firmware', (effectively 'soup' (Software of Uncertain Pedigree)) which must be assessed in accordance with relevant safety standards before it may be used in a safety application. Particular standards are IEC 61508 [1] and the British Energy (BE) PES (Programmable Electronic Systems) guidelines EPD/GEN/REP/0277/97. [2] This paper outlines a new instrument evaluation system, which has been developed in conjunction with the UK Nuclear Industry. The paper concludes with a discussion about on-line monitoring of Smart instrumentation in safety critical applications. (author)

  15. Time dependent non-extinction probability for prompt critical systems

    International Nuclear Information System (INIS)

    Gregson, M. W.; Prinja, A. K.

    2009-01-01

    The time dependent non-extinction probability equation is presented for slab geometry. Numerical solutions are provided for a nested inner/outer iteration routine where the fission terms (both linear and non-linear) are updated and then held fixed over the inner scattering iteration. Time dependent results are presented highlighting the importance of the injection position and angle. The iteration behavior is also described as the steady state probability of initiation is approached for both small and large time steps. Theoretical analysis of the nested iteration scheme is shown and highlights poor numerical convergence for marginally prompt critical systems. An acceleration scheme for the outer iterations is presented to improve convergence of such systems. Theoretical analysis of the acceleration scheme is also provided and the associated decrease in computational run time addressed. (authors)

  16. FEATURES, EVENTS, AND PROCESSES: SYSTEM-LEVEL AND CRITICALITY

    Energy Technology Data Exchange (ETDEWEB)

    D.L. McGregor

    2000-12-20

    The primary purpose of this Analysis/Model Report (AMR) is to identify and document the screening analyses for the features, events, and processes (FEPs) that do not easily fit into the existing Process Model Report (PMR) structure. These FEPs include the 3 1 FEPs designated as System-Level Primary FEPs and the 22 FEPs designated as Criticality Primary FEPs. A list of these FEPs is provided in Section 1.1. This AMR (AN-WIS-MD-000019) documents the Screening Decision and Regulatory Basis, Screening Argument, and Total System Performance Assessment (TSPA) Disposition for each of the subject Primary FEPs. This AMR provides screening information and decisions for the TSPA-SR report and provides the same information for incorporation into a project-specific FEPs database. This AMR may also assist reviewers during the licensing-review process.

  17. Structural Materials for Innovative Nuclear Systems (SMINS-3) - Workshop Proceedings, Idaho National Laboratory, Idaho Falls, United States, 7-10 October 2013

    International Nuclear Information System (INIS)

    2015-01-01

    The development of innovative nuclear systems such as Gen IV reactors or critical and subcritical transmutation systems requires a good knowledge of the properties of the materials used for designing these reactors. A common feature in developing nuclear systems is the widely recognised need for experimental programmes to select and characterise structural materials. Structural materials research, both at national and international level, can significantly contribute to the future deployment of new systems. Since 2007, the OECD Nuclear Energy Agency Nuclear Science Committee organises a series of workshop on Structural Materials for Innovative Nuclear Systems (SMINS) to stimulate an exchange of information on current materials research programmes for innovative nuclear systems with a view to identifying and developing potential synergies. The third workshop was held on 7-10 October 2013 in Idaho Falls (United States) and organised through the collaboration of the Working Party on Scientific Issues of the Fuel Cycle (WPFC) and the Working Party on Multi-Scale Modelling of Fuels and Structural Materials for Nuclear Systems (WPMM) in co-operation with the European Community (EC) and the International Atomic Energy Agency (IAEA). A total of 74 abstracts were received for either an oral and poster presentation. These proceedings include the papers presented at the workshop

  18. Flight critical system design guidelines and validation methods

    Science.gov (United States)

    Holt, H. M.; Lupton, A. O.; Holden, D. G.

    1984-01-01

    Efforts being expended at NASA-Langley to define a validation methodology, techniques for comparing advanced systems concepts, and design guidelines for characterizing fault tolerant digital avionics are described with an emphasis on the capabilities of AIRLAB, an environmentally controlled laboratory. AIRLAB has VAX 11/750 and 11/780 computers with an aggregate of 22 Mb memory and over 650 Mb storage, interconnected at 256 kbaud. An additional computer is programmed to emulate digital devices. Ongoing work is easily accessed at user stations by either chronological or key word indexing. The CARE III program aids in analyzing the capabilities of test systems to recover from faults. An additional code, the semi-Markov unreliability program (SURE) generates upper and lower reliability bounds. The AIRLAB facility is mainly dedicated to research on designs of digital flight-critical systems which must have acceptable reliability before incorporation into aircraft control systems. The digital systems would be too costly to submit to a full battery of flight tests and must be initially examined with the AIRLAB simulation capabilities.

  19. Critical Education for Systemic Change: A World-Systems Analysis Perspective

    Science.gov (United States)

    Griffiths, Tom G.

    2015-01-01

    This paper both draws on, and seeks to apply, world-systems analysis to a broad, critical education project that builds mass schooling's potential contribution to the process of world-systemic change. In short, this is done by first setting out the world-systems analysis account of the current state, and period of transition, of the capitalist…

  20. Verification and Validation of Flight-Critical Systems

    Science.gov (United States)

    Brat, Guillaume

    2010-01-01

    For the first time in many years, the NASA budget presented to congress calls for a focused effort on the verification and validation (V&V) of complex systems. This is mostly motivated by the results of the VVFCS (V&V of Flight-Critical Systems) study, which should materialize as a a concrete effort under the Aviation Safety program. This talk will present the results of the study, from requirements coming out of discussions with the FAA and the Joint Planning and Development Office (JPDO) to technical plan addressing the issue, and its proposed current and future V&V research agenda, which will be addressed by NASA Ames, Langley, and Dryden as well as external partners through NASA Research Announcements (NRA) calls. This agenda calls for pushing V&V earlier in the life cycle and take advantage of formal methods to increase safety and reduce cost of V&V. I will present the on-going research work (especially the four main technical areas: Safety Assurance, Distributed Systems, Authority and Autonomy, and Software-Intensive Systems), possible extensions, and how VVFCS plans on grounding the research in realistic examples, including an intended V&V test-bench based on an Integrated Modular Avionics (IMA) architecture and hosted by Dryden.

  1. Smart Power Supply Systems for Mission Critical Facilities

    Science.gov (United States)

    Hirose, Keiichi; Babasaki, Tadatoshi

    To develop the advanced and rich life, and the also economy and social activity continuously, various types of energy are necessary. At the same time, to protect the global environment and to prevent the depletion of natural resources, the effective and moreover efficient use of energy is becoming important. Electric power is one of the most important forms of energy for our life and society. This paper describes topics and survey results of technical trends regarding the electric power supply systems which are playing a core role as the important infrastructure to support the emergence of information-oriented society. Specifically, the power supply systems that enhance high power quality and reliability (PQR) are important for the steady growth of information and communication services. The direct current (DC) power, which has been used for telecommunications power systems and information and communications technologies (ICT), enables existing utilities' grid and distributed energy resources to keep a balance between supply and demand of small-scaled power systems or microgirds. These techniques are expected to be part of smartgrid technologies and facilitate the installation of distributed generators in mission critical facilities.

  2. Scaling Law for Irreversible Entropy Production in Critical Systems.

    Science.gov (United States)

    Hoang, Danh-Tai; Prasanna Venkatesh, B; Han, Seungju; Jo, Junghyo; Watanabe, Gentaro; Choi, Mahn-Soo

    2016-06-09

    We examine the Jarzynski equality for a quenching process across the critical point of second-order phase transitions, where absolute irreversibility and the effect of finite-sampling of the initial equilibrium distribution arise in a single setup with equal significance. We consider the Ising model as a prototypical example for spontaneous symmetry breaking and take into account the finite sampling issue by introducing a tolerance parameter. The initially ordered spins become disordered by quenching the ferromagnetic coupling constant. For a sudden quench, the deviation from the Jarzynski equality evaluated from the ideal ensemble average could, in principle, depend on the reduced coupling constant ε0 of the initial state and the system size L. We find that, instead of depending on ε0 and L separately, this deviation exhibits a scaling behavior through a universal combination of ε0 and L for a given tolerance parameter, inherited from the critical scaling laws of second-order phase transitions. A similar scaling law can be obtained for the finite-speed quench as well within the Kibble-Zurek mechanism.

  3. Using fuzzy self-organising maps for safety critical systems

    International Nuclear Information System (INIS)

    Kurd, Zeshan; Kelly, Tim P.

    2007-01-01

    This paper defines a type of constrained artificial neural network (ANN) that enables analytical certification arguments whilst retaining valuable performance characteristics. Previous work has defined a safety lifecycle for ANNs without detailing a specific neural model. Building on this previous work, the underpinning of the devised model is based upon an existing neuro-fuzzy system called the fuzzy self-organising map (FSOM). The FSOM is type of 'hybrid' ANN which allows behaviour to be described qualitatively and quantitatively using meaningful expressions. Safety of the FSOM is argued through adherence to safety requirements-derived from hazard analysis and expressed using safety constraints. The approach enables the construction of compelling (product-based) arguments for mitigation of potential failure modes associated with the FSOM. The constrained FSOM has been termed a 'safety critical artificial neural network' (SCANN). The SCANN can be used for non-linear function approximation and allows certified learning and generalisation for high criticality roles. A discussion of benefits for real-world applications is also presented

  4. Analysis of Creep Crack Growth Behavior of Alloy 617 for Use in a VHTR System

    International Nuclear Information System (INIS)

    Kim, Woo-Gon; Kim, Min-Hwan; Park, Jae-Young; Ekaputra, I. M. W.; Kim, Seon-Jin

    2015-01-01

    Alloy 617 is a major candidate material for the IHX component. The design of the component, which will operate well into the creep range, will require a good understanding of creep crack growth deformation. Efforts are now being undertaken in the Gen-IV program to provide data needed for the design and licensing of the nuclear plants, and with this goal in mind, to meet the needs of the conceptual designers of the VHTR system, 'Gen-IV Materials Handbook' is being established through an international collaboration program of GIF (Gen-IV Forum) countries. To logically obtain the B and q values in the CCGR equation, three methods in terms of LSFM, MVM, and PDM were adopted. The PDM was most useful. Both the B and q coefficients followed a lognormal distribution. Using a lognormal distribution in the PDM, a number of random variables were generated by Monte Carlo Simulation, and the CCGR lines could be successfully predicted from the viewpoint of reliability

  5. Critical factors in the implementation process of integrated management systems

    Directory of Open Access Journals (Sweden)

    Ademir Antonio Ferreira

    2015-09-01

    Full Text Available This study is the result of research whose purpose was to study the implementation process of integrated management systems, called ERP Enterprise Resource Planning in the business environment. This study, more specifically, tried to identify the variables in this process and that, somehow, made it easy or caused some type of difficulty implementing the system. Based on the mixed method approach (Creswell, 2003, the study was performed by means of the content analysis of technical and scientific publications about this theme and by means of a field research for data collection from primary sources. The content analysis was based on the per mile procedure by Bardin (1977, making it possible to identify critical factors that may be found in the implementation of ERP system projects. Primary data was collected from structured interviews with the managers in charge of the implementation of the system, in each of the 12 companies in different sectors of the economy and based in Brazil. Based on this information, it was possible to test the factors extracted from the content analysis and then develop a list of factors that may effectively influence the implementation process of the system. In order to recognize the possible relations between the selected factors, the Spearman (rsp correlation coefficient was applied and the multiple regression analysis was performed by means of the stepwise procedure. The purpose of the regression analysis was to determine the relation of the “Assessment of the Implementation” dependent variable with other dependent variables in the selected categories. The results of these analyses showed that the support of the top management, the communication process for the clear evidence of this support, the technical support of the ERP program provider together with the project team expertise, training and qualification processes of the team in the system operation are significantly correlated and relevant factors for a

  6. Quantum uncertainty in critical systems with three spins interaction

    International Nuclear Information System (INIS)

    Carrijo, Thiago M; Avelar, Ardiley T; Céleri, Lucas C

    2015-01-01

    In this article we consider two spin-1/2 chains described, respectively, by the thermodynamic limit of the XY model with the usual two site interaction, and an extension of this model (without taking the thermodynamics limit), called XYT, were a three site interaction term is presented. To investigate the critical behaviour of such systems we employ tools from quantum information theory. Specifically, we show that the local quantum uncertainty, a quantity introduced in order to quantify the minimum quantum share of the variance of a local measurement, can be used to indicate quantum phase transitions presented by these models at zero temperature. Due to the connection of this quantity with the quantum Fisher information, the results presented here may be relevant for quantum metrology and quantum thermodynamics. (paper)

  7. Critical mm-wave components for synthetic automatic test systems

    CERN Document Server

    Hrobak, Michael

    2015-01-01

    Michael Hrobak studied hybrid integrated front end modules for high frequency measurement equipment and especially for synthetic automatic test systems. Recent developments of innovative, critical millimeter-wave components like frequency multipliers, directional couplers, filters, triple balanced mixers and power detectors are illustrated by the author separately and in combination.  Contents Synthetic Instruments Resistive Diode Frequency Multipliers Planar Directional Couplers and Filters Triple Balanced Mixers Zero Bias Schottky Power Detectors Integrated Front End Assemblies  Target Groups Scientists and students in the field of electrical engineering with main emphasis on high frequency technology Engineers and Practitioners dealing with the development of micro- and millimeter-wave measurement instruments  About the Author Dr. Michael Hrobak is with the Microwave Department of the Ferdinand-Braun-Institut (FBH), Berlin, Germany, where he is involved in the development and measurement of monolithic i...

  8. A critical review of clinical trials in systemic lupus erythematosus

    Science.gov (United States)

    Mahieu, Mary A.; Strand, Vibeke; Simon, Lee S.; Lipsky, Peter E.; Ramsey-Goldman, Rosalind

    2016-01-01

    One challenge in caring for patients with systemic lupus erythematosus (SLE) is a paucity of approved therapeutics for treatment of the diverse disease manifestations. In the last 60 years, only one drug, belimumab, has been approved for SLE treatment. Critical evaluation of investigator initiated and pharma-sponsored randomized controlled trials (RCTs) highlights barriers to successful drug development in SLE, including disease heterogeneity, inadequate trial size or duration, insufficient dose finding before initiation of large trials, handling of background medications, and choice of primary endpoint. Herein we examine lessons learned from landmark SLE RCTs and subsequent advances in trial design, as well as discuss efforts to address limitations in current SLE outcome measures that will improve detection of true therapeutic responses in future RCTs. PMID:27497257

  9. Development of a criticality monitoring and alarm system

    International Nuclear Information System (INIS)

    Egey, Julio; Izraelevitch, Federico H.; Matatagui, Emilio

    2009-01-01

    In this work we are presenting the development of a Criticality Monitor and Alarm System (SIMAC). It monitors the burst of radiation produced during such an accident and triggers an alarm for evacuation in case the radiation exceeds a pre-established threshold. It consists of two subsystems, one for gamma rays and the other for neutrons. Each subsystem has three independent detectors modules. Each module is composed of an ion chamber plus its associated electronics, feeding a logic module that in turn would trigger the evacuation alarm. An additional feature is a PC interface for data acquisition. The radiation detectors are ion chambers working in current mode. The electronics associated to each detector can manage a wide signal range using a logarithmic converter. (author)

  10. Critical Vulnerability: Defending the Decisive Point of United States Computer Networked Information Systems

    National Research Council Canada - National Science Library

    Virden, Roy

    2003-01-01

    .... The military's use of computer networked information systems is thus a critical strength. These systems are then critical vulnerabilities because they may lack adequate protection and are open to enemy attack...

  11. Effects of stressor characteristics on early warning signs of critical transitions and "critical coupling" in complex dynamical systems.

    Science.gov (United States)

    Blume, Steffen O P; Sansavini, Giovanni

    2017-12-01

    Complex dynamical systems face abrupt transitions into unstable and catastrophic regimes. These critical transitions are triggered by gradual modifications in stressors, which push the dynamical system towards unstable regimes. Bifurcation analysis can characterize such critical thresholds, beyond which systems become unstable. Moreover, the stochasticity of the external stressors causes small-scale fluctuations in the system response. In some systems, the decomposition of these signal fluctuations into precursor signals can reveal early warning signs prior to the critical transition. Here, we present a dynamical analysis of a power system subjected to an increasing load level and small-scale stochastic load perturbations. We show that the auto- and cross-correlations of bus voltage magnitudes increase, leading up to a Hopf bifurcation point, and further grow until the system collapses. This evidences a gradual transition into a state of "critical coupling," which is complementary to the established concept of "critical slowing down." Furthermore, we analyze the effects of the type of load perturbation and load characteristics on early warning signs and find that gradient changes in the autocorrelation provide early warning signs of the imminent critical transition under white-noise but not for auto-correlated load perturbations. Furthermore, the cross-correlation between all voltage magnitude pairs generally increases prior to and beyond the Hopf bifurcation point, indicating "critical coupling," but cannot provide early warning indications. Finally, we show that the established early warning indicators are oblivious to limit-induced bifurcations and, in the case of the power system model considered here, only react to an approaching Hopf bifurcation.

  12. Evaluation of Critical Parameters to Improve Slope Drainage System

    Directory of Open Access Journals (Sweden)

    Yong Weng Long

    2017-01-01

    Full Text Available This study focuses on identifying and evaluating critical parameters of various drainage configurations, arrangement, and filter which affect the efficiency of water draining system in slopes. There are a total of seven experiments with different types of homogeneous soil, drainage envelope, filter material, and quantity of pipes performed utilizing a model box with a dimension of 0.8 m × 0.8 m × 0.6 m. The pipes were orientated at 5 degrees from the horizontal. Rainfall event was introduced via a rainfall simulator with rainfall intensity of 434.1 mm/h. From the experiments performed, the expected outcomes when utilizing double pipes and geotextile as envelope filter were verified in this study. The results obtained from these experiments were reviewed and compared with Chapter 14 “Subsurface Drainage Systems” of DID’s Irrigation and Agricultural Drainage Manual of Malaysia and the European standard. It is recommended that the pipe installed in the slope could be wrapped with geotextile and in tandem with application of granular filter to minimize clogging without affecting the water discharge rate. Terzaghi’s filter criteria could be followed closely when deciding on new materials to act as aggregate filter. A caging system could be introduced as it could maintain the integrity of the drainage system and could ease installation.

  13. Nanostructured delivery systems with improved leishmanicidal activity: a critical review.

    Science.gov (United States)

    Bruni, Natascia; Stella, Barbara; Giraudo, Leonardo; Della Pepa, Carlo; Gastaldi, Daniela; Dosio, Franco

    2017-01-01

    Leishmaniasis is a vector-borne zoonotic disease caused by protozoan parasites of the genus Leishmania , which are responsible for numerous clinical manifestations, such as cutaneous, visceral, and mucocutaneous leishmaniasis, depending on the site of infection for particular species. These complexities threaten 350 million people in 98 countries worldwide. Amastigotes living within macrophage phagolysosomes are the principal target of antileishmanial treatment, but these are not an easy target as drugs must overcome major structural barriers. Furthermore, limitations on current therapy are related to efficacy, toxicity, and cost, as well as the length of treatment, which can increase parasitic resistance. Nanotechnology has emerged as an attractive alternative as conventional drugs delivered by nanosized carriers have improved bioavailability and reduced toxicity, together with other characteristics that help to relieve the burden of this disease. The significance of using colloidal carriers loaded with active agents derives from the physiological uptake route of intravenous administered nanosystems (the phagocyte system). Nanosystems are thus able to promote a high drug concentration in intracellular mononuclear phagocyte system (MPS)-infected cells. Moreover, the versatility of nanometric drug delivery systems for the deliberate transport of a range of molecules plays a pivotal role in the design of therapeutic strategies against leishmaniasis. This review discusses studies on nanocarriers that have greatly contributed to improving the efficacy of antileishmaniasis drugs, presenting a critical review and some suggestions for improving drug delivery.

  14. Martin Marietta Energy Systems Nuclear Criticality Safety Improvement Program

    International Nuclear Information System (INIS)

    Speas, I.G.

    1987-01-01

    This report addresses questions raised by criticality safety violation at several DOE plants. Two charts are included that define the severity and reporting requirements for the six levels of accidents. A summary is given of all reported criticality incident at the DOE plants involved. The report concludes with Martin Marietta's Nuclear Criticality Safety Policy Statement

  15. Coulomb systems seen as critical systems: Finite-size effects in two dimensions

    International Nuclear Information System (INIS)

    Jancovici, B.; Manificat, G.; Pisani, C.

    1994-01-01

    It is known that the free energy at criticality of a finite two-dimensional system of characteristic size L has in general a term which behaves like log L as L → ∞; the coefficient of this term is universal. There are solvable models of two-dimensional classical Coulomb systems which exhibit the same finite-size correction (except for its sign) although the particle correlations are short-ranged, i.e., noncritical. Actually, the electrical potential and electrical field correlations are critical at all temperatures (as long as the Coulomb system is a conductor), as a consequence of the perfect screening property of Coulomb systems. This is why Coulomb systems have to exhibit critical finite-size effects

  16. Inverse Problems in Systems Biology: A Critical Review.

    Science.gov (United States)

    Guzzi, Rodolfo; Colombo, Teresa; Paci, Paola

    2018-01-01

    Systems Biology may be assimilated to a symbiotic cyclic interplaying between the forward and inverse problems. Computational models need to be continuously refined through experiments and in turn they help us to make limited experimental resources more efficient. Every time one does an experiment we know that there will be some noise that can disrupt our measurements. Despite the noise certainly is a problem, the inverse problems already involve the inference of missing information, even if the data is entirely reliable. So the addition of a certain limited noise does not fundamentally change the situation but can be used to solve the so-called ill-posed problem, as defined by Hadamard. It can be seen as an extra source of information. Recent studies have shown that complex systems, among others the systems biology, are poorly constrained and ill-conditioned because it is difficult to use experimental data to fully estimate their parameters. For these reasons was born the concept of sloppy models, a sequence of models of increasing complexity that become sloppy in the limit of microscopic accuracy. Furthermore the concept of sloppy models contains also the concept of un-identifiability, because the models are characterized by many parameters that are poorly constrained by experimental data. Then a strategy needs to be designed to infer, analyze, and understand biological systems. The aim of this work is to provide a critical review to the inverse problems in systems biology defining a strategy to determine the minimal set of information needed to overcome the problems arising from dynamic biological models that generally may have many unknown, non-measurable parameters.

  17. A PEDAGOGICAL CRITICAL REVIEW OF ONLINE LEARNING SYSTEM

    Directory of Open Access Journals (Sweden)

    Dwi SULISWORO

    2016-08-01

    Full Text Available E-learning which have various shapes such as blog, classroom learning which is facilitated the World Wide Web; a mix of online instruction and meeting the class known as additional models or hybrid; or the full online experience, where all assessment and instruction is done electronically. Object relationship of learning and constructivist educational philosophy and confirmed that online learning has the orientation which is basically a constructivist ideology, where the combination of some of the knowledge is an inquiry-oriented activities and authentic and also promote the progress of the construction of new knowledge. Description of the online learning system in theory and practice can be illustrated in a few examples that have been found in the research that has been done and found new discoveries obtained in the study, but not everything can be done because of several factors. Please note that the components in the online learning system can serve as a learning system which is very strong influence on learning in the class. The objective of this research is to a pedagogical critical review of online learning system in theory and practice that can be applied by teachers in the teaching process in the classroom. The results obtained in this study were teachers and students need extra effort to make online classes and virtual. Further research is needed on appropriate strategies in order to determine the next result is more useful. There some advices for any studies that discuss online learning system are done in certain areas, namely the use of electricity and other disciplines such as social and humanities.

  18. Licensing process for safety-critical software-based systems

    Energy Technology Data Exchange (ETDEWEB)

    Haapanen, P. [VTT Automation, Espoo (Finland); Korhonen, J. [VTT Electronics, Espoo (Finland); Pulkkinen, U. [VTT Automation, Espoo (Finland)

    2000-12-01

    System vendors nowadays propose software-based technology even for the most critical safety functions in nuclear power plants. Due to the nature of software faults and the way they cause system failures new methods are needed for the safety and reliability evaluation of these systems. In the research project 'Programmable automation systems in nuclear power plants (OHA)', financed together by the Radiation and Nuclear Safety Authority (STUK), the Ministry of Trade and Industry (KTM) and the Technical Research Centre of Finland (VTT), various safety assessment methods and tools for software based systems are developed and evaluated. As a part of the OHA-work a reference model for the licensing process for software-based safety automation systems is defined. The licensing process is defined as the set of interrelated activities whose purpose is to produce and assess evidence concerning the safety and reliability of the system/application to be licensed and to make the decision about the granting the construction and operation permissions based on this evidence. The parties of the licensing process are the authority, the licensee (the utility company), system vendors and their subcontractors and possible external independent assessors. The responsibility about the production of the evidence in first place lies at the licensee who in most cases rests heavily on the vendor expertise. The evaluation and gauging of the evidence is carried out by the authority (possibly using external experts), who also can acquire additional evidence by using their own (independent) methods and tools. Central issue in the licensing process is to combine the quality evidence about the system development process with the information acquired through tests, analyses and operational experience. The purpose of the licensing process described in this report is to act as a reference model both for the authority and the licensee when planning the licensing of individual applications

  19. Licensing process for safety-critical software-based systems

    International Nuclear Information System (INIS)

    Haapanen, P.; Korhonen, J.; Pulkkinen, U.

    2000-12-01

    System vendors nowadays propose software-based technology even for the most critical safety functions in nuclear power plants. Due to the nature of software faults and the way they cause system failures new methods are needed for the safety and reliability evaluation of these systems. In the research project 'Programmable automation systems in nuclear power plants (OHA)', financed together by the Radiation and Nuclear Safety Authority (STUK), the Ministry of Trade and Industry (KTM) and the Technical Research Centre of Finland (VTT), various safety assessment methods and tools for software based systems are developed and evaluated. As a part of the OHA-work a reference model for the licensing process for software-based safety automation systems is defined. The licensing process is defined as the set of interrelated activities whose purpose is to produce and assess evidence concerning the safety and reliability of the system/application to be licensed and to make the decision about the granting the construction and operation permissions based on this evidence. The parties of the licensing process are the authority, the licensee (the utility company), system vendors and their subcontractors and possible external independent assessors. The responsibility about the production of the evidence in first place lies at the licensee who in most cases rests heavily on the vendor expertise. The evaluation and gauging of the evidence is carried out by the authority (possibly using external experts), who also can acquire additional evidence by using their own (independent) methods and tools. Central issue in the licensing process is to combine the quality evidence about the system development process with the information acquired through tests, analyses and operational experience. The purpose of the licensing process described in this report is to act as a reference model both for the authority and the licensee when planning the licensing of individual applications. Many of the

  20. 48 CFR 1852.246-70 - Mission Critical Space System Personnel Reliability Program.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Mission Critical Space... CONTRACT CLAUSES Texts of Provisions and Clauses 1852.246-70 Mission Critical Space System Personnel Reliability Program. As prescribed in 1846.370(a), insert the following clause: Mission Critical Space System...

  1. Critical care providers refer to information tools less during communication tasks after a critical care clinical information system introduction.

    Science.gov (United States)

    Ballermann, Mark; Shaw, Nicola T; Mayes, Damon C; Gibney, R T Noel

    2011-01-01

    Electronic documentation methods may assist critical care providers with information management tasks in Intensive Care Units (ICUs). We conducted a quasi-experimental observational study to investigate patterns of information tool use by ICU physicians, nurses, and respiratory therapists during verbal communication tasks. Critical care providers used tools less at 3 months after the CCIS introduction. At 12 months, care providers referred to paper and permanent records, especially during shift changes. The results suggest potential areas of improvement for clinical information systems in assisting critical care providers in ensuring informational continuity around their patients.

  2. System Dynamics Approach for Critical Infrastructure and Decision Support. A Model for a Potable Water System.

    Science.gov (United States)

    Pasqualini, D.; Witkowski, M.

    2005-12-01

    The Critical Infrastructure Protection / Decision Support System (CIP/DSS) project, supported by the Science and Technology Office, has been developing a risk-informed Decision Support System that provides insights for making critical infrastructure protection decisions. The system considers seventeen different Department of Homeland Security defined Critical Infrastructures (potable water system, telecommunications, public health, economics, etc.) and their primary interdependencies. These infrastructures have been modeling in one model called CIP/DSS Metropolitan Model. The modeling approach used is a system dynamics modeling approach. System dynamics modeling combines control theory and the nonlinear dynamics theory, which is defined by a set of coupled differential equations, which seeks to explain how the structure of a given system determines its behavior. In this poster we present a system dynamics model for one of the seventeen critical infrastructures, a generic metropolitan potable water system (MPWS). Three are the goals: 1) to gain a better understanding of the MPWS infrastructure; 2) to identify improvements that would help protect MPWS; and 3) to understand the consequences, interdependencies, and impacts, when perturbations occur to the system. The model represents raw water sources, the metropolitan water treatment process, storage of treated water, damage and repair to the MPWS, distribution of water, and end user demand, but does not explicitly represent the detailed network topology of an actual MPWS. The MPWS model is dependent upon inputs from the metropolitan population, energy, telecommunication, public health, and transportation models as well as the national water and transportation models. We present modeling results and sensitivity analysis indicating critical choke points, negative and positive feedback loops in the system. A general scenario is also analyzed where the potable water system responds to a generic disruption.

  3. Reforming EIA systems: A critical review of proposals in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Alberto, E-mail: albertof@em.ufop.br [Federal University of Ouro Preto, Minas Gerais (Brazil); Sánchez, Luis Enrique [University of São Paulo, São Paulo (Brazil); Ribeiro, José Claudio Junqueira [Escola Superior Dom Helder Câmara, Belo Horizonte, Minas Gerais (Brazil)

    2017-01-15

    Environmental Impact Assessment (EIA) systems are under pressure in many countries, driven by a call for efficiency and streamlining. Such a phenomenon is particularly clear in Brazil, where, in the past few years, a number of influential associations put forward documents proposing significant changes to environmental licensing and impact assessment regulations. So far, there is no publicly available information about any initiative towards scrutinizing those proposals. The objective of this study was to critically review the merits and drawbacks of the changes proposed in those documents. The analysis triangulated content analysis, focus group and online survey data. The focus group included ten seasoned Brazilian EIA specialists; the survey, based on Likert-scale and open-ended questions, resulted in 322 valid responses from EIA professionals. Results show that the proposals generally agree that the current EIA system, while playing a key role in mitigating impacts and enhancing project design, needs many changes. Nonetheless, the proposals neither offered solutions to overcome political, technical and budget barriers, nor established a sense of priority of the most urgent issues. Findings from the focus group and the survey signaled that a number of proposed actions might face public outcry, and that those changes that do not depend on legislative action are more likely to be implementable. Previous studies about EIA reform focused mostly on the context of developed countries after changes had taken place. This study, while addressing the perspective of a large developing country in a “before-reform” stage, shows that capacity-building is a key requirement in EIA reform. - Highlights: • Brazil's EIA system is under strong pressure for change. • Findings corroborate ineffectiveness in current system. • There are tensions as to the best approaches to overcome problems. • Exact effects of proposals are uncertain. • Low institutional capacity can

  4. Criticality safety analysis of accelerator transmutation waste system

    International Nuclear Information System (INIS)

    Landeyro, P.A.; Cepraga, D.G.; Orazi, A.

    1993-01-01

    The Accelerator Transmutation Waste system (ATW) is under development at the Los Alamos National Laboratory. It consists of a particle accelerator producing a proton beam having an energy of 1.5 GeV. These particles are introduced into the upper part of a molten Pb-Bi column and they produce, by a spallation reaction, a high strength neutron flux, 1.0x10 16 n/(square centimeters sec). The neutrons enter a heavy water blanket where actinides and long-lived fission products circulate in vertical tubes. The goal of this research effort is to perform an independent verification of the feasibility of actinide burning in the ATW system. The work is divided into four tasks: a) production of an actinide and long-lived fission product cross section library from JEF 2.2; b) simulation, using MCNP and KENO IV Monte Carlo codes, of the ATW configurations existing in literature; c) validation of the cross sections by comparison of Keff and reaction rate results, calculated with MCNP and KENO IV, with experimental benchmarks and intercomparison between calculations of a PWR unit cell and the computations carried out with various codes and cross section libraries (NEACRF criticality working group data); d) simulation of the ATW configuration. The two first tasks are almost complete with excellent agreement between this study's results and those of Los Alamos

  5. Lack of Critical Slowing Down Suggests that Financial Meltdowns Are Not Critical Transitions, yet Rising Variability Could Signal Systemic Risk

    Science.gov (United States)

    Hoarau, Quentin

    2016-01-01

    Complex systems inspired analysis suggests a hypothesis that financial meltdowns are abrupt critical transitions that occur when the system reaches a tipping point. Theoretical and empirical studies on climatic and ecological dynamical systems have shown that approach to tipping points is preceded by a generic phenomenon called critical slowing down, i.e. an increasingly slow response of the system to perturbations. Therefore, it has been suggested that critical slowing down may be used as an early warning signal of imminent critical transitions. Whether financial markets exhibit critical slowing down prior to meltdowns remains unclear. Here, our analysis reveals that three major US (Dow Jones Index, S&P 500 and NASDAQ) and two European markets (DAX and FTSE) did not exhibit critical slowing down prior to major financial crashes over the last century. However, all markets showed strong trends of rising variability, quantified by time series variance and spectral function at low frequencies, prior to crashes. These results suggest that financial crashes are not critical transitions that occur in the vicinity of a tipping point. Using a simple model, we argue that financial crashes are likely to be stochastic transitions which can occur even when the system is far away from the tipping point. Specifically, we show that a gradually increasing strength of stochastic perturbations may have caused to abrupt transitions in the financial markets. Broadly, our results highlight the importance of stochastically driven abrupt transitions in real world scenarios. Our study offers rising variability as a precursor of financial meltdowns albeit with a limitation that they may signal false alarms. PMID:26761792

  6. Reactor noise in critical and accelerator driven sub-critical systems

    International Nuclear Information System (INIS)

    Degweker, S.B.; Rana, Y.S.

    2007-01-01

    Noise methods have long been used for reactor kinetics parameters measurement and as diagnostic tools for monitoring the health of a nuclear power plant. It is conceivable that noise techniques would find similar applications in ADS. Measurement/monitoring the degree of sub-criticality of an ADS is one such application for which noise based methods are being considered, among others such as the pulsed source method. For this reason, theoretical studies on ADS noise have appeared since the late nineties. The principal difference between critical reactor noise and ADS noise is due to the statistical properties of the source. Unlike the source due to radioactive decay present in ordinary reactors, the machine produced ADS source cannot be assumed to be a Poisson process. In addition the source is pulsed. All this requires a new theoretical approach to the subject. In a number of papers (beginning in 2000) such a theoretical approach has been developed in BARC. Over the years, our approach has received general acceptance. The paper gives a description of the subject of reactor noise and its applications in critical reactors. The theory of noise in ADS is then outlined, highlighting the differences in approach and results from that of critical reactors. (author)

  7. The Microcirculation System in Critical Conditions Caused by Abdominal Sepsis

    Directory of Open Access Journals (Sweden)

    S. L. Kan

    2011-01-01

    Full Text Available Objective: to evaluate the microcirculation system in critical conditions caused by abdominal sepsis for a further differentiated approach to intensive care. Subjects and methods. Twenty-four patients with abdominal sepsis (mean age 42.9±0.9 years were examined; a control group consisted of 35 apparently healthy individuals (mean age 40.1±2.1 years. Over 11 days, the microcirculatory bed was evaluated by cutaneous laser Doppler flowmetry by means of a ЛАКК-02 laser capillary blood flow analyzer made in the Russian Federation (LAZMA Research-and-Production Association, by using a basic light guide for percutaneous microcirculation studies. Results. Throughout the study, tissue blood perfusion remained in the patients with sepsis due to the higher effect of mainly active components of vascular tone regulation on the microvascular bed. In a poor outcome, there was a reduction in both active and passive regulatory effects on tissue perfusion chiefly due to local (myogenic factors. Conclusion. The findings suggest that the patients with sepsis have microcirculatory regulation changes aimed at maintaining tissue perfusion. A follow-up of the microcirculation may be useful in choosing intensive care tactics and predicting disease outcome. Key words: sepsis, microcirculation, microvascular bed, micro blood flow, tissue perfusion.

  8. Urban Systems and Energy Consumptions: A Critical Approach

    Directory of Open Access Journals (Sweden)

    Rocco Papa

    2014-05-01

    Full Text Available City transformations are also due to the development of new energy sources, which have influenced economy and lifestyles, as well as the physical and functional organization of urban systems. Cities are the key place where it is need to act for the achievement of strategic environmental objectives, such as reducing greenhouse gas emissions and energy saving. The hard resolution of these challenges depends on several factors: their multidimensional nature, the change of the economic and settlement development model, and also the complexity of the relationships between the elements that constitute the urban systems and that affect energy consumption. According to this awareness the Project Smart Energy Master for the energy management of territory financed by PON 04A2_00120 R & C Axis II, from 2012 to 2015 has been developed: it is aimed at supporting local authorities in the development of strategies for the reduction of energy consumption through actions designed to change behavior (in terms of use and energy consumption and to improve the energy efficiency of equipment and infrastructure. With the goal of describing some of the results of the methodological phase of this project, this paper proposes a review of the major studies on the issue of energy consumption at the urban scale in the first section; in the second section the outcomes of the first phase of the development of the comprehension/interpretive model related to the identification of the set of physical/environmental variables at urban scale, that most affect the energy consumption, are described; the third makes a critical review of the reference scientific literature, characterised by a too sectoral approach, compared to the complexity of the topic.

  9. Multi-critical points in weakly anisotropic magnetic systems

    International Nuclear Information System (INIS)

    Basten, J.A.J.

    1979-02-01

    This report starts with a rather extensive presentation of the concepts and ideas which constitute the basis of the modern theory of static critical phenomena. It is shown how at a critical point the semi-phenomenological concepts of universality and scaling are directly related to the divergence of the correlation length and how they are extended to a calculational method for critical behaviour in Wilson's Renormalization-Group (RG) approach. Subsequently the predictions of the molecular-field and RG-theories on the phase transitions and critical behaviour in weakly anisotropic antiferromagnets are treated. In a magnetic field applied along the easy axis, these materials can display an (H,T) phase diagram which contains either a bicritical point or a tetracritical point. Especially the behaviour close to these multi-critical points, as predicted by the extended-scaling theory, is discussed. (Auth.)

  10. Health systems guidance appraisal--a critical interpretive synthesis.

    Science.gov (United States)

    Ako-Arrey, Denis E; Brouwers, Melissa C; Lavis, John N; Giacomini, Mita K

    2016-01-22

    Health systems guidance (HSG) are systematically developed statements that assist with decisions about options for addressing health systems challenges, including related changes in health systems arrangements. However, the development, appraisal, and reporting of HSG poses unique conceptual and methodological challenges related to the varied types of evidence that are relevant, the complexity of health systems, and the pre-eminence of contextual factors. To address this gap, we are conducting a program of research that aims to create a tool to support the appraisal of HSG and further enhance HSG development and reporting. The focus of this paper was to conduct a knowledge synthesis of the published and grey literatures to determine quality criteria (concepts) relevant for this process. We applied a critical interpretive synthesis (CIS) approach to knowledge synthesis that enabled an iterative, flexible, and dynamic analysis of diverse bodies of literature in order to generate a candidate list of concepts that will constitute the foundational components of the HSG tool. Using our review questions as compasses, we were able to guide the search strategy to look for papers based on their potential relevance to HSG appraisal, development, and reporting. The search strategy included various electronic databases and sources, subject-specific journals, conference abstracts, research reports, book chapters, unpublished data, dissertations, and policy documents. Screening the papers and data extraction was completed independently and in duplicate, and a narrative approach to data synthesis was executed. We identified 43 papers that met eligibility criteria. No existing review was found on this topic, and no HSG appraisal tool was identified. Over one third of the authors implicitly or explicitly identified the need for a high-quality tool aimed to systematically evaluate HSG and contribute to its development/reporting. We identified 30 concepts that may be relevant to the

  11. The design of a new criticality incident detection and alarm system

    International Nuclear Information System (INIS)

    Nobes, T.S.

    1999-01-01

    This paper presents a general review of criticality and its detection. After a brief description of what a criticality incident involves, an outline is given of detection methods and warning systems. (author)

  12. Critical behaviour in very pure Ni-Ta systems

    International Nuclear Information System (INIS)

    Oddou, J.L.; Berthier, J.; Peretto, P.

    1978-01-01

    The authors use the perturbed angular correlation technique to follow the behaviour of the magnetic hyperfine field on 181 Ta in nickel in the critical region of the matrix. Contrary to what is expected, it is observed that the critical exponent associated to the hyperfine field is different from the critical exponent associated to the bulk magnetization. Because the concentrations of the various impurities are very low, the authors think that the explanation of the phenomenon is to be found in the framework of a one-impurity model interacting with the surrounding spins via an isotropic exchange energy

  13. Maintaining Mission Critical Systems in a 247 Environment

    CERN Document Server

    Curtis, Peter M

    2011-01-01

    "This book is meant to offer Architects, Property Mangers, Facility Managers, Building Engineers, Information Technology Professionals, Data Center Personnel, Electrical & Mechanical Technicians and students in undergraduate, graduate, or continuing education programs relevant insight into the Mission Critical Environment with an emphasis on business resiliency, data center efficiency, and green power technology. Industry improvements, standards, and techniques have been incorporated into the text and address the latest issues prevalent in the Mission Critical Industry. An emphasis on green technologies and certifications is presented throughout the book. In addition, a description of the United States energy infrastructure's dependency on oil, in relation to energy security in the mission critical industry, is discussed. In conjunction with this, either a new chapter will be created on updated policies and regulations specifically related to the mission critical industry or updates to policies and regula...

  14. Dependability analysis of a safety critical system the LHC beam dumping system at CERN

    CERN Document Server

    Filippini, R

    2006-01-01

    This thesis presents the dependability study of the Beam Dumping System of the Large Hadron Collider (LHC), the high energy particle accelerator to be commissioned at CERN in summer 2007. There are two identical, independent LHC Beam Dumping Systems (LBDS), one per LHC beam, each consisting of a series of magnets that extract the particle beam from the LHC ring into the extraction line leading to the absorbing block. The consequences of a failure within the LBDS can be very severe. This risk is reduced by applying redundancy to the design of the most critical components and on-line surveillance that, in case of a detected failure, issues a safe operation abort, called false beam dump. The system has been studied applying Failure Modes Effects and Criticality Analysis (FMECA) and reliability prediction. The system failure processes have been represented with a state transition diagram, governed by a Markov regenerative stochastic process, and analysed for different operational scenarios for one year of operati...

  15. Washing and chilling as critical control points in pork slaughter hazard analysis and critical control point (HACCP) systems.

    Science.gov (United States)

    Bolton, D J; Pearce, R A; Sheridan, J J; Blair, I S; McDowell, D A; Harrington, D

    2002-01-01

    The aim of this research was to examine the effects of preslaughter washing, pre-evisceration washing, final carcass washing and chilling on final carcass quality and to evaluate these operations as possible critical control points (CCPs) within a pork slaughter hazard analysis and critical control point (HACCP) system. This study estimated bacterial numbers (total viable counts) and the incidence of Salmonella at three surface locations (ham, belly and neck) on 60 animals/carcasses processed through a small commercial pork abattoir (80 pigs d(-1)). Significant reductions (P HACCP in pork slaughter plants. This research will provide a sound scientific basis on which to develop and implement effective HACCP in pork abattoirs.

  16. Parametric Optimization of Some Critical Operating System Functions--An Alternative Approach to the Study of Operating Systems Design

    Science.gov (United States)

    Sobh, Tarek M.; Tibrewal, Abhilasha

    2006-01-01

    Operating systems theory primarily concentrates on the optimal use of computing resources. This paper presents an alternative approach to teaching and studying operating systems design and concepts by way of parametrically optimizing critical operating system functions. Detailed examples of two critical operating systems functions using the…

  17. Role of the surface in the critical behavior of finite systems

    Energy Technology Data Exchange (ETDEWEB)

    Duflot, V.; Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Gulminelli, F. [Laboratoire de Physique Corpusculaire, LPC-ISMRa, CNRS-IN2P3, 14 - Caen (France)

    2000-07-01

    The role of surfaces in a finite system undergoing a critical phenomenon is discussed in a canonical lattice-gas model. Surfaces are constrained by a mean volume defined via a La grange multiplier. We show that critical fragment size distributions are conserved even in very small systems with surfaces. This implies that critical signals are still relevant in the study of phase transitions in finite systems. (authors)

  18. Major factors in critical equipment reliability - Auxiliary systems; The development of an auxiliary system

    International Nuclear Information System (INIS)

    Forsthoffer, W.E.

    1992-01-01

    In this article, the author details the development of an actual auxiliary system in order to fully understand the function of each major component and how it contributes to the total operation and reliability of the system. Only after the function of an auxiliary system is thoroughly understood, can one proceed to discuss specifications, design audits, testing, operation and preventive maintenance. The application selected will be to develop a pressurized lubrication and steam turbine control oil system for the critical equipment unit. This example was selected since many readers will be familiar with this type and because it provides a good foundation towards understanding fluid sealing systems. In the exercise that follow, he will define the system requirements and determine the system parameters. This information will then be used for component sizing

  19. Lambda phage genetic switch as a system with critical behaviour

    Czech Academy of Sciences Publication Activity Database

    Vohradský, Jiří

    2017-01-01

    Roč. 431, OCT 27 2017 (2017), s. 32-38 ISSN 0022-5193 R&D Projects: GA MŠk(CZ) LM2015055 Institutional support: RVO:61388971 Keywords : Critical behaviour * Phage lambda * Genetic networks Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 2.113, year: 2016

  20. DNS as critical infrastructure, the energy system case study

    NARCIS (Netherlands)

    Casalicchio, E.; Gheorghe, A.V.; Caselli, M.; Coletta, A.; Nai Fovino, I.

    2013-01-01

    Modern critical infrastructures (e.g., power plants, energy grids, oil pipelines, etc.), make nowadays extensive use of information and communication technologies (ICT). As a direct consequence their exposure to cyber-attacks is becoming a matter of public security. In this paper, we analyse a

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

    Energy Technology Data Exchange (ETDEWEB)

    Stevens-Guille, P D

    1974-02-28

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

  2. Critical masses of miniexplosion in fission-fusion hybrid systems

    Energy Technology Data Exchange (ETDEWEB)

    Kaliski, S [Polska Akademia Nauk, Warsaw. Inst. Podstawowych Problemow Techniki

    1976-01-01

    The critical mass of the fissionable material subjected to the explosive compression and the action of the neutron stream originating from the process of D-T fusion in the spherical cavity was estimated. High energy recovery from the fissionable material was obtained and the energy of the laser pulse was minimized.

  3. Critical scaling of a jammed system after a quench of temperature.

    Science.gov (United States)

    Otsuki, Michio; Hayakawa, Hisao

    2012-09-01

    Critical behavior of soft repulsive particles after quench of temperature near the jamming transition is numerically investigated. It is found that the plateau of the mean-square displacement of tracer particles and the pressure satisfy critical scaling laws. The critical density for the jamming transition depends on the protocol to prepare the system, while the values of the critical exponents which are consistent with the prediction of a phenomenology are independent of the protocol.

  4. Critical incidence reporting systems - an option in equine anaesthesia? Results from a panel meeting.

    Science.gov (United States)

    Hartnack, Sonja; Bettschart-Wolfensberger, Regula; Driessen, Bernd; Pang, Daniel; Wohlfender, Franziska

    2013-11-01

    To provide a brief introduction into Critical Incident Reporting Systems (CIRS) as used in human medicine, and to report the discussion from a recent panel meeting discussion with 23 equine anaesthetists in preparation for a new CEPEF-4 (Confidential Enquiry into Perioperative Equine Fatalities) study. Moderated group discussions, and review of literature. The first group discussion focused on the definition of 'preventable critical incidents' and/or 'near misses' in the context of equine anaesthesia. The second group discussion focused on categorizing critical incidents according to an established framework for analysing risk and safety in clinical medicine. While critical incidents do occur in equine anaesthesia, no critical incident reporting system including systematic collection and analysis of critical incidents is in place. Critical incident reporting systems could be used to improve safety in equine anaesthesia - in addition to other study types such as mortality studies. © 2013 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

  5. Increment 23/24 Critical Readiness Review Health Maintenance System

    Science.gov (United States)

    Nieschwitz, Linda

    2010-01-01

    This slide presentation reviews the Health Maintenance System. It includes information on the carbon dioxide (CO2) and moisture removal system (CMRS), the variable oxygen system,rendevous station panels, and the crew contamination protection kit (CCPK).

  6. Critical dynamics of an interacting magnetic nanoparticle system

    DEFF Research Database (Denmark)

    Hansen, Mikkel Fougt; Jonsson, P.E.; Nordblad, P.

    2002-01-01

    Effects of dipole-dipole interactions on the magnetic relaxation have been investigated for three Fe-C nanoparticle samples with volume concentrations of 0.06, 5 and 17 vol%. While both the 5 and 17 vol% samples exhibit collective behaviour due to dipolar interactions, only the 17 vol% sample dis...... displays critical behaviour close to its transition temperature. The behaviour of the 5 vol% sample can be attributed to a mixture of collective and single-particle dynamics....

  7. Life extension decision making of safety critical systems: An overview

    OpenAIRE

    Shafiee, Mahmood; Animah, I.

    2017-01-01

    In recent years, the concept of “asset life extension” has become increasingly important to safety critical industries including nuclear power, offshore oil and gas, petrochemical, renewable energy, rail transport, aviation, shipping, electricity distribution and transmission, etc. Extending the service life of industrial assets can offer a broad range of economic, technical, social and environmental benefits as compared to other end-of-life management strategies such as decommissioning and r...

  8. Year 2000 Compliance of Selected Mission Critical Command, Control, and Communications Systems Managed by The Defense Information Systems Agency

    National Research Council Canada - National Science Library

    1999-01-01

    ...) has adequately planned for and managed year 2000 conversion risks to avoid undue disruption to selected mission critical command, control, and communications systems used in support of Unified...

  9. RICIS Symposium 1992: Mission and Safety Critical Systems Research and Applications

    Science.gov (United States)

    1992-01-01

    This conference deals with computer systems which control systems whose failure to operate correctly could produce the loss of life and or property, mission and safety critical systems. Topics covered are: the work of standards groups, computer systems design and architecture, software reliability, process control systems, knowledge based expert systems, and computer and telecommunication protocols.

  10. Developments in solar still desalination systems: A critical review

    KAUST Repository

    Ayoub, George M.

    2012-10-01

    Solar still desalination uses a sustainable and pollution-free source to produce high-quality water. The main limitation is low productivity and this has been the focus of intensive research. A major concern while increasing productivity is to maintain economic feasibility and simplicity. The authors present a critical review of the research work conducted on solar stills development. Studies addressing each parameter of concern are grouped together and results compared. Novelty in design and newly introduced features are presented. Modeling efforts of flow circulation within the still and methods to estimate internal heat transfer coefficients are discussed and future research needs are outlined. © 2012 Taylor & Francis Group, LLC.

  11. Critical review of expert system validation in transportation

    Science.gov (United States)

    1997-01-01

    Expert system validationthat is, testing systems to ascertain whether they achieve acceptable performance levelshas with few exceptions been ad hoc, informal, and of dubious value. Very few efforts have been made in this regard in the transport...

  12. Optical System Critical Design Review (CDR) Flight Software Summary

    Science.gov (United States)

    Khorrami, Mori

    2006-01-01

    The Mid Infrared Instrument (MIRI FSW presentation covers: (1) Optical System FSW only and Cooling System FSW is covered at its CDR (2) Requirements & Interfaces (3) Relationship with the ISIM FSW (4) FSW Design Drivers & Solutions.

  13. Critical Infrastructure: Control Systems and the Terrorist Threat

    National Research Council Canada - National Science Library

    Shea, Dana A

    2003-01-01

    .... Industrial control computer systems involved in this infrastructure are specific points of vulnerability, as cyber-security for these systems has not been previously perceived as a high priority...

  14. Critical Infrastructure: Control Systems and the Terrorist Threat

    National Research Council Canada - National Science Library

    Shea, Dana A

    2004-01-01

    .... Industrial control computer systems involved in this infrastructure are specific points of vulnerability, as cyber-security for these systems has not been previously perceived as a high priority...

  15. Critical location identification and vulnerability analysis of interdependent infrastructure systems under spatially localized attacks

    International Nuclear Information System (INIS)

    Ouyang, Min

    2016-01-01

    Infrastructure systems are usually spatially distributed in a wide area and are subject to many types of hazards. For each type of hazards, modeling their direct impact on infrastructure components and analyzing their induced system-level vulnerability are important for identifying mitigation strategies. This paper mainly studies spatially localized attacks that a set of infrastructure components located within or crossing a circle shaped spatially localized area is subject to damage while other components do not directly fail. For this type of attacks, taking interdependent power and gas systems in Harris County, Texas, USA as an example, this paper proposes an approach to exactly identify critical locations in interdependent infrastructure systems and make pertinent vulnerability analysis. Results show that (a) infrastructure interdependencies and attack radius largely affect the position of critical locations; (b) spatially localized attacks cause less vulnerability than equivalent random failures; (c) in most values of attack radius critical locations identified by considering only node failures do not change when considering both node and edge failures in the attack area; (d) for many values of attack radius critical locations identified by topology-based model are also critical from the flow-based perspective. - Highlights: • We propose a method to identify critical locations in interdependent infrastructures. • Geographical interdependencies and attack radius largely affect critical locations. • Localized attacks cause less vulnerability than equivalent random failures. • Whether considering both node and edge failures affects critical locations. • Topology-based critical locations are also critical from flow-based perspective.

  16. Existing experimental criticality data applicable to nuclear-fuel-transportation systems

    International Nuclear Information System (INIS)

    Bierman, S.R.

    1983-02-01

    Analytical techniques are generally relied upon in making criticality evaluations involving nuclear material outside reactors. For these evaluations to be accepted the calculations must be validated by comparison with experimental data for a known set of conditions having physical and neutronic characteristics similar to those conditions being evaluated analytically. The purpose of this report is to identify those existing experimental data that are suitable for use in verifying criticality calculations on nuclear fuel transportation systems. In addition, near term needs for additional data in this area are identified. Of the considerable amount of criticality data currently existing, that are applicable to non-reactor systems, those particularly suitable for use in support of nuclear material transportation systems have been identified and catalogued into the following groups: (1) critical assemblies of fuel rods in water; (2) critical assemblies of fuel rods in water containing soluble neutron absorbers; (3) critical assemblies containing solid neutron absorber; (4) critical assemblies of fuel rods in water with heavy metal reflectors; and (5) critical assemblies of fuel rods in water with irregular features. A listing of the current near term needs for additional data in each of the groups has been developed for future use in planning criticality research in support of nuclear fuel transportation systems. The criticality experiments needed to provide these data are briefly described and identified according to priority and relative cost of performing the experiments

  17. Composable Virtual Platforms for Mixed-Criticality Embedded Systems

    NARCIS (Netherlands)

    Beyranvand Nejad, A.

    2014-01-01

    Recent trends show a steady increase towards concurrently executing more and more applications on a single embedded system. Multi-Processor System-on-Chip (MPSoC) architectures are proposed to allow complex design of embedded systems. This is achieved by integrating as many processing resources as

  18. Composable virtual platforms for mixed-criticality embedded systems

    NARCIS (Netherlands)

    Nejad, A.B.

    2014-01-01

    Recent trends show a steady increase towards concurrently executing more and more applications on a single embedded system. Multi-Processor System-on-Chip (MPSoC) architectures are proposed to allow complex design of embedded systems. This is achieved by integrating as many processing resources as

  19. Identifying bottlenecks in manufacturing systems using stochastic criticality analysis

    NARCIS (Netherlands)

    Nogueira Bastos, J.P.; van der Sanden, L.J.; Donk, O.; Voeten, J.P.M.; Stuijk, S.; Schiffelers, R.R.H.; Corporaal, H.

    2018-01-01

    System design is a difficult process with many design-choices for which the impact may be difficult to foresee. Manufacturing system design is no exception to this. Increased use of flexible manufacturing systems which are able to perform different operations/use-cases further raises the design

  20. Productivity Implications of Employee Performance Appraisal System : A Critical Survey.

    OpenAIRE

    Dr. VSR Subramaniam

    2004-01-01

    The Productivity of any organisation is directly correlated to the Effectiveness of the Employee Performance Appraisal System, subject to the Effectiveness of the Support Systems, depending upon the type of organizational business. INFERENCE : Technology, Systems and Manpower are linked in an inter- related circle focusing towards Productivity =============================================================== DOCTORAL (Ph.D) RESEARCH WORK OF DR.VSR.SUBRAMANIAM IN JAMNALAL BAJAJ INSTITUTE OF MANA...

  1. A Review of Accident Modelling Approaches for Complex Critical Sociotechnical Systems

    National Research Council Canada - National Science Library

    Qureshi, Zahid H

    2008-01-01

    .... This report provides a review of key traditional accident modelling approaches and their limitations, and describes new system-theoretic approaches to the modelling and analysis of accidents in safety-critical systems...

  2. Systems analysis determining critical items, critical assembly processes, primary failure modes and corrective actions on ASST magnets

    International Nuclear Information System (INIS)

    Arden, C.S.

    1993-04-01

    During the assembly process through the completion of the Accelerator Surface String Test (ASST) phase one test, Magnet Systems Division Reliability Engineering has tracked all the known discrepancies utilizing the Failure Reporting, Analysis and Corrective Action System (FRACAS) and data base. This paper discusses the critical items, critical assembly processes, primary failure modes and corrective actions (lessons learned) based on actual data for the ASST magnets. The ASST magnets include seven Brookhaven Lab Dipoles (DCA-207 through 213), fourteen Fermi Lab Dipoles (DCA-310 through 323) and five Lawrence Berkeley Lab Quadrupoles (QCC-402 through 406). Between all the ASST magnets built there were one hundred eighty six (186) class one discrepancies reported out of approximately eleven hundred total discrepancy reports. The class one or critical discrepancies are defined as form, fit, function, safety or reliability problem. Each and every ASST magnet is considered a success, as they all achieved the quench performance requirements and were capable of being incorporated into the string test. This paper also discuss some specific magnet discrepancies, including failure cause(s), corrective action and possible open issues

  3. Systems analysis determining critical items, critical assembly processes, primary failure modes and corrective actions on ASST magnets

    International Nuclear Information System (INIS)

    Arden, C.S.

    1994-01-01

    During the assembly process through the completion of the Accelerator Surface String Test (ASST) phase one test, Magnet Systems Division Reliability Engineering has tracked all the known discrepancies utilizing the Failure Reporting, Analysis and Corrective Action System (FRACAS) and data base. This paper discusses the critical items, critical assembly processes, primary failure modes and corrective actions (lessons learned) based on actual data for the ASST magnets. The ASST magnets include seven Brookhaven Lab Dipoles (DCA-207 through 213), fourteen Fermi Lab Dipoles (DCA-310 through 323) and five Lawrence Berkeley Lab Quadrupoles (QCC-402 through 406). Between all the ASST magnets built there were one hundred eighty six (186) class one discrepancies reported out of approximately eleven hundred total discrepancy reports. The class one or critical discrepancies are defined as form, fit, function, safety or reliability problem. Each and every ASST magnet is considered a success, as they all achieved the quench performance requirements and were capable of being incorporated into the string test. This paper will also discuss some specific magnet discrepancies, including failure cause(s), corrective action and possible open issues

  4. System for prediction and determination of the sub critic multiplication

    International Nuclear Information System (INIS)

    Martinez, Aquilino S.; Pereira, Valmir; Silva, Fernando C. da

    1997-01-01

    It is presented a concept of a system which may be used to calculate and anticipate the subcritical multiplication of a PWR nuclear power plant. The system is divided into two different modules. The first module allows the theoretical prediction of the subcritical multiplication factor through the solution of the multigroup diffusion equation. The second module determines this factor based on the data acquired from the neutron detectors of a NPP external nuclear detection system. (author). 3 refs., 3 figs., 2 tabs

  5. Design of Mixed-Criticality Applications on Distributed Real-Time Systems

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian

    the concept of virtual links, and temporal separation, enforced through schedule tables for TT messages and bandwidth allocation for RC messages. The objective of this thesis is to develop methods and tools for distributed mixed-criticality real-time systems. At the processor level, we are interested......A mixed-criticality system implements applications of different safety-criticality levels onto the same platform. In such cases, the certification standards require that applications of different criticality levels are protected so they cannot influence each other. Otherwise, all tasks have...

  6. Critical Success Factors of Suggestions Systems. | Marx | IFE ...

    African Journals Online (AJOL)

    A literature study approach is followed to establish which factors contribute to the success and failure of various suggestion systems. It was found ... The value of the paper firstly, shows the importance of creativity and innovation within the organisation's own culture and the framework of a formal suggestion system. Secondly ...

  7. Critical Uses of College Resources. Part I: Personnel Utilization System.

    Science.gov (United States)

    Vlahos, Mantha

    A Personnel Utilization System has been designed at Broward Community College, which combines payroll, personnel, course, and function information in order to determine the actual duties performed by personnel for the amount of remuneration received. Objectives of the system are (1) to define the tasks being performed by faculty, staff, and…

  8. Systems biology of lactic acid bacteria: a critical review.

    Science.gov (United States)

    Teusink, Bas; Bachmann, Herwig; Molenaar, Douwe

    2011-08-30

    Understanding the properties of a system as emerging from the interaction of well described parts is the most important goal of Systems Biology. Although in the practice of Lactic Acid Bacteria (LAB) physiology we most often think of the parts as the proteins and metabolites, a wider interpretation of what a part is can be useful. For example, different strains or species can be the parts of a community, or we could study only the chemical reactions as the parts of metabolism (and forgetting about the enzymes that catalyze them), as is done in flux balance analysis. As long as we have some understanding of the properties of these parts, we can investigate whether their interaction leads to novel or unanticipated behaviour of the system that they constitute. There has been a tendency in the Systems Biology community to think that the collection and integration of data should continue ad infinitum, or that we will otherwise not be able to understand the systems that we study in their details. However, it may sometimes be useful to take a step back and consider whether the knowledge that we already have may not explain the system behaviour that we find so intriguing. Reasoning about systems can be difficult, and may require the application of mathematical techniques. The reward is sometimes the realization of unexpected conclusions, or in the worst case, that we still do not know enough details of the parts, or of the interactions between them. We will discuss a number of cases, with a focus on LAB-related work, where a typical systems approach has brought new knowledge or perspective, often counterintuitive, and clashing with conclusions from simpler approaches. Also novel types of testable hypotheses may be generated by the systems approach, which we will illustrate. Finally we will give an outlook on the fields of research where the systems approach may point the way for the near future.

  9. Coupled CFD - system-code simulation of a gas cooled reactor

    International Nuclear Information System (INIS)

    Yan, Yizhou; Rizwan-uddin

    2011-01-01

    A generic coupled CFD - system-code thermal hydraulic simulation approach was developed based on FLUENT and RELAP-3D, and applied to LWRs. The flexibility of the coupling methodology enables its application to advanced nuclear energy systems. Gas Turbine - Modular Helium Reactor (GT-MHR) is a Gen IV reactor design which can benefit from this innovative coupled simulation approach. Mixing in the lower plenum of the GT-MHR is investigated here using the CFD - system-code coupled simulation tool. Results of coupled simulations are presented and discussed. The potential of the coupled CFD - system-code approach for next generation of nuclear power plants is demonstrated. (author)

  10. Detecting, anticipating, and predicting critical transitions in spatially extended systems.

    Science.gov (United States)

    Kwasniok, Frank

    2018-03-01

    A data-driven linear framework for detecting, anticipating, and predicting incipient bifurcations in spatially extended systems based on principal oscillation pattern (POP) analysis is discussed. The dynamics are assumed to be governed by a system of linear stochastic differential equations which is estimated from the data. The principal modes of the system together with corresponding decay or growth rates and oscillation frequencies are extracted as the eigenvectors and eigenvalues of the system matrix. The method can be applied to stationary datasets to identify the least stable modes and assess the proximity to instability; it can also be applied to nonstationary datasets using a sliding window approach to track the changing eigenvalues and eigenvectors of the system. As a further step, a genuinely nonstationary POP analysis is introduced. Here, the system matrix of the linear stochastic model is time-dependent, allowing for extrapolation and prediction of instabilities beyond the learning data window. The methods are demonstrated and explored using the one-dimensional Swift-Hohenberg equation as an example, focusing on the dynamics of stochastic fluctuations around the homogeneous stable state prior to the first bifurcation. The POP-based techniques are able to extract and track the least stable eigenvalues and eigenvectors of the system; the nonstationary POP analysis successfully predicts the timing of the first instability and the unstable mode well beyond the learning data window.

  11. Analyzing Software Errors in Safety-Critical Embedded Systems

    Science.gov (United States)

    Lutz, Robyn R.

    1994-01-01

    This paper analyzes the root causes of safty-related software faults identified as potentially hazardous to the system are distributed somewhat differently over the set of possible error causes than non-safety-related software faults.

  12. Critical early mission design considerations for lunar data systems architecture

    Science.gov (United States)

    Hei, Donald J., Jr.; Stephens, Elaine

    1992-01-01

    This paper outlines recent early mission design activites for a lunar data systems architecture. Each major functional element is shown to be strikingly similar when viewed in a common reference system. While this similarity probably deviates with lower levels of decomposition, the sub-functions can always be arranged into similar and dissimilar categories. Similar functions can be implemented as objects - implemented once and reused several times like today's advanced integrated circuits. This approach to mission data systems, applied to other NASA programs, may result in substantial agency implementation and maintenance savings. In today's zero-sum-game budgetary environment, this approach could help to enable a lunar exploration program in the next decade. Several early mission studies leading to such an object-oriented data systems design are recommended.

  13. A Testbed for Highly-Scalable Mission Critical Information Systems

    National Research Council Canada - National Science Library

    Birman, Kenneth P

    2005-01-01

    ... systems in a networked environment. Headed by Professor Ken Birman, the project is exploring a novel fusion of classical protocols for reliable multicast communication with a new style of peer-to-peer protocol called scalable "gossip...

  14. system hardening architecture for safer access to critical business

    African Journals Online (AJOL)

    eobe

    System hardening is a defence strategy, where several different security measures are applied at various layers, all of which .... commerce have tremendously imparted on corporate services ..... Technology and Exploring Engineering, Vol. 2,.

  15. Performance modeling in critical engineering systems using RAM analysis

    International Nuclear Information System (INIS)

    Sharma, Rajiv Kumar; Kumar, Sunand

    2008-01-01

    Reliability, availability and maintainability (RAM) analysis of system is helpful in carrying out design modifications, if any, required to achieve minimum failures or to increase mean time between failures (MTBF) and thus to plan maintainability requirements, optimize reliability and maximize equipment availability. To this effect, the paper presents the application of RAM analysis in a process industry. Markovian approach is used to model the system behavior. For carrying out analysis, transition diagrams for various subsystems are drawn and differential equations associated with them are formulated. After obtaining the steady state solution the corresponding values of reliability and maintainability are estimated at different mission times. The computed results are presented to plant personnel for their active consideration. The results proved helpful to them for analyzing the system behavior and thereby to improve the system performance considerably by adopting and practicing suitable maintenance policies/strategies

  16. Detecting critical illness outside the ICU: the role of track and trigger systems.

    Science.gov (United States)

    Jansen, Jan O; Cuthbertson, Brian H

    2010-06-01

    Critical illness is often preceded by physiological deterioration. Track and trigger systems are intended to facilitate the timely recognition of patients with potential or established critical illness outside critical care areas. The aim of this article is to review the evidence for the use of such systems. Existing track and trigger systems have low sensitivity, low positive predictive values, and high specificity. They often fail to identify patients who need additional care and have not been shown to improve outcomes. The development of such systems must be based on robust methodological and statistical principles. At present, few track and trigger systems meet these standards. Although track and trigger systems, combined with appropriate response algorithms, have the potential to improve the recognition and management of critical illness, further work is required to validate their utility.

  17. Critical Theory as a foundation for Pragmatic Information Systems Design

    OpenAIRE

    Gerald Benoît

    2001-01-01

    This paper considers how designers of information systems and end-user perspectives, communication models and linguistic behaviors differ. A critique of these differences is made by applying Habermas's communicative action principles. An empirical study of human-human information seeking, based on those principles, indicates which behaviors are predictors of successful interactions and so are candidate behaviors may be integrated into computerized information systems.

  18. A System for Managing Critical Knowledge for Accelerator Subsystems: Pansophy

    International Nuclear Information System (INIS)

    C. Reece; V. Bookwalter; B. Madre

    2001-01-01

    Accelerator development and construction projects often intentionally push the envelope of well-established technical performance and manageable complexity. In addition, the desire for efficient retention and exploitation of accumulated experience across the multi-decade life cycles of major installations calls for a robust, yet user-friendly knowledge management system. To meet these needs, we are presently deploying a new web-based system at Jefferson Lab: Pansophy. This system is a custom integration of several commercial software utilities, DocushareTM, ColdFusionTM, MatlabTM, IngresTM, and common desktop programs. Users of the system range from process managers, shop-floor technicians, test engineers, to after-the-fact data miners and operations staff. The system integrates important QA elements of procedural control, automated data accumulation into a secured central database, prompt and reliable data query and retrieval, and online analysis tools, all accessed by the user via their platform-independent web browser. A system overview, completed pilot project, and implementation experience to date will be presented

  19. Time-critical multirate scheduling using contemporary real-time operating system services

    Science.gov (United States)

    Eckhardt, D. E., Jr.

    1983-01-01

    Although real-time operating systems provide many of the task control services necessary to process time-critical applications (i.e., applications with fixed, invariant deadlines), it may still be necessary to provide a scheduling algorithm at a level above the operating system in order to coordinate a set of synchronized, time-critical tasks executing at different cyclic rates. The scheduling requirements for such applications and develops scheduling algorithms using services provided by contemporary real-time operating systems.

  20. Critical Components in Microfluidic Systems for Drug Delivery

    DEFF Research Database (Denmark)

    Bitsch, Lennart

    2006-01-01

    Formålet med denne afhandling har været at evaluere mulighederne for at anvende mikrofluide systemer til medicinsk behandling. Vi har især fokuseret på sikkerhed i reciprokerende pumper, med henblik på en kontinuer insulin behandling, og har identificeret mikroventiler som værende kritiske......-mikroventil. Sammenlignet med systemer der benytter passive ventiler opnår vi et markant højere sikkerhedsniveau med en drejeventil. Teknologien bygger på konstruktion med bløde inkompressible gummimaterialer, og hårde overflader. Grundlæggende studier af dynamisk friktion mellem gummi og en hård overflade viser...... dreje-mikroventiler med gode pakninsgsegenskaber. De overvejende fordele ved nedskalering af mekaniske systemer er mere kompakte, lavenergi-apparater. Vi har vist muligheden for at lave dreje-mikroventiler med lavt energiforbrug og gode pakningsegenskaber ved konstruktion og test af en demonstrator med...

  1. Intermediate probabilistic safety assessment approach for safety critical digital systems

    International Nuclear Information System (INIS)

    Taeyong, Sung; Hyun Gook, Kang

    2001-01-01

    Even though the conventional probabilistic safety assessment methods are immature for applying to microprocessor-based digital systems, practical needs force to apply it. In the Korea, UCN 5 and 6 units are being constructed and Korean Next Generation Reactor is being designed using the digital instrumentation and control equipment for the safety related functions. Korean regulatory body requires probabilistic safety assessment. This paper analyzes the difficulties on the assessment of digital systems and suggests an intermediate framework for evaluating their safety using fault tree models. The framework deals with several important characteristics of digital systems including software modules and fault-tolerant features. We expect that the analysis result will provide valuable design feedback. (authors)

  2. Retention systems for extraoral maxillofacial prosthetic implants: a critical review.

    Science.gov (United States)

    Cobein, M V; Coto, N P; Crivello Junior, O; Lemos, J B D; Vieira, L M; Pimentel, M L; Byrne, H J; Dias, R B

    2017-10-01

    We describe the techniques available for retention of implant-supported prostheses: bar-clips, O-rings, and magnets. We present reported preferences and, although this is limited by the heterogeneity of methods used and patients studied, we hope we have identified the best retention systems for maxillofacial prosthetic implants. If practitioners know the advantages and disadvantages of each system, they can choose the most natural and comfortable prosthesis. We searched the PubMed and Scopus databases, and restricted our search to papers published 2001-13. MeSH terms used were Maxillofacial prosthesis and Craniofacial prosthesis OR Craniofacial prostheses. We found a total of 2630 papers, and after duplicates had been removed we analysed the rest and found 25 papers for review. Of these, 12 were excluded because they were case reports or non-systematic reviews. Of the remaining 13, 10 described group analyses and seemed appropriate to find practitioner's choices, as cited in the abstract (n=1611 prostheses). Three papers did not mention the type of prosthetic connection used, so were excluded. The most popular choices for different conditions were analysed, though the sites and retention systems were not specified in all 10 papers. The bar-clip system was the most used in auricular (6/10 papers) and nasal prostheses (4/10). For the orbital region, 6/10 favoured magnets. Non-osseointegrated mechanical or adhesive retention techniques are the least expensive and have no contraindications. When osseointegrated implants are possible, each facial region has a favoured system. The choice of system is influenced by two factors: standard practice and the abilities of the maxillofacial surgeon and maxillofacial prosthetist. Copyright © 2017 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  3. Current and Future Critical Issues in Rocket Propulsion Systems

    Science.gov (United States)

    Navaz, Homayun K.; Dix, Jeff C.

    1998-01-01

    The objective of this research was to tackle several problems that are currently of great importance to NASA. In a liquid rocket engine several complex processes take place that are not thoroughly understood. Droplet evaporation, turbulence, finite rate chemistry, instability, and injection/atomization phenomena are some of the critical issues being encountered in a liquid rocket engine environment. Pulse Detonation Engines (PDE) performance, combustion chamber instability analysis, 60K motor flowfield pattern from hydrocarbon fuel combustion, and 3D flowfield analysis for the Combined Cycle engine were of special interest to NASA. During the summer of 1997, we made an attempt to generate computational results for all of the above problems and shed some light on understanding some of the complex physical phenomena. For this purpose, the Liquid Thrust Chamber Performance (LTCP) code, mainly designed for liquid rocket engine applications, was utilized. The following test cases were considered: (1) Characterization of a detonation wave in a Pulse Detonation Tube; (2) 60K Motor wall temperature studies; (3) Propagation of a pressure pulse in a combustion chamber (under single and two-phase flow conditions); (4) Transonic region flowfield analysis affected by viscous effects; (5) Exploring the viscous differences between a smooth and a corrugated wall; and (6) 3D thrust chamber flowfield analysis of the Combined Cycle engine. It was shown that the LTCP-2D and LTCP-3D codes are capable of solving complex and stiff conservation equations for gaseous and droplet phases in a very robust and efficient manner. These codes can be run on a workstation and personal computers (PC's).

  4. National Plant Germplasm System: Critical Role of Customer Service

    Science.gov (United States)

    The National Plant Germplasm System (NPGS) conserves plant genetic resources, not only for use by future generations, but for immediate use by scientists and educators around the world. With a great deal of interaction between genebank curators and users of plant genetic resources, customer service...

  5. Critical parameters in the design of urban soakaway systems in ...

    African Journals Online (AJOL)

    The influence of the hydraulic characteristics of subsurface soils in the performance of septicsoakaway systems is studied to achieve a very realistic design. In-situ infiltration tests were conducted on three marked horizons between 0 and 400 cm below the ground surface. Soil samples taken from the same locations were ...

  6. A Multiscale Modeling System: Developments, Applications, and Critical Issues

    Science.gov (United States)

    Tao, Wei-Kuo; Lau, William; Simpson, Joanne; Chern, Jiun-Dar; Atlas, Robert; Khairoutdinov, David Randall Marat; Li, Jui-Lin; Waliser, Duane E.; Jiang, Jonathan; Hou, Arthur; hide

    2009-01-01

    The foremost challenge in parameterizing convective clouds and cloud systems in large-scale models are the many coupled dynamical and physical processes that interact over a wide range of scales, from microphysical scales to the synoptic and planetary scales. This makes the comprehension and representation of convective clouds and cloud systems one of the most complex scientific problems in Earth science. During the past decade, the Global Energy and Water Cycle Experiment (GEWEX) Cloud System Study (GCSS) has pioneered the use of single-column models (SCMs) and cloud-resolving models (CRMs) for the evaluation of the cloud and radiation parameterizations in general circulation models (GCMs; e.g., GEWEX Cloud System Science Team 1993). These activities have uncovered many systematic biases in the radiation, cloud and convection parameterizations of GCMs and have led to the development of new schemes (e.g., Zhang 2002; Pincus et al, 2003; Zhang and Wu 2003; Wu et al. 2003; Liang and Wu 2005; Wu and Liang 2005, and others). Comparisons between SCMs and CRMs using the same large-scale forcing derived from field campaigns have demonstrated that CRMs are superior to SCMs in the prediction of temperature and moisture tendencies (e.g., Das et al. 1999; Randall et al 2003b; Xie et al. 2005).

  7. Critical Appraisal of the System of Education and Prospects of ...

    African Journals Online (AJOL)

    The main purpose of this article is to review the South African system of education and assess the country's prospects of meeting current and future manpower and developmental needs. This inquiry is based primarily on an assessment of the current status quo in education in South Africa in order to gain a better ...

  8. Calculation of critical fault recovery time for nonlinear systems based on region of attraction analysis

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Blanke, Mogens

    2014-01-01

    of a system. It must be guaranteed that the trajectory of a system subject to fault remains in the region of attraction (ROA) of the post-fault system during this time. This paper proposes a new algorithm to compute the critical fault recovery time for nonlinear systems with polynomial vector elds using sum...

  9. Hospital accounting and information systems: a critical assessment.

    Science.gov (United States)

    Macintosh, N B

    1991-01-01

    Public sector organisations seem to be caught up in the global wave of 'neo-Thatcherism'. As such, they are being held 'accountable' today by their respective government finance departments for the costs and benefits of the services they provide to the general public. As the public purse tightens, hospitals (and related health service units) more and more compete with other public sector organisations (old-age pensions and services, post-secondary education, day-care centres, port authorities, unemployment insurance, parks and recreation, elite sport programs, aboriginal peoples aid and development, and so on) for a diminishing piece of what seems a smaller and smaller pie. In this 'fight-for-funding', hospitals seem particularly vulnerable. Sky-rocketing costs, public resentment of doctors' high income and a deliberate restriction and limiting of medical school places, among other things, contribute to general public antagonism. The message for hospitals is that cost-effective accountability will loom large when hospitals come begging at the public trough. Even left-wing politicians today seem to be heeding the words of free-market economists like Freedman of Chicago. 'Privatisation' is the constant threat for those deemed inefficient. As a consequence, hospital administrators around the world, caught up in this trend, seem to be stampeding to 'boot-up' some kind of new accounting information system. For example, at my own university hospital (Queen's University, Kingston, Canada), the hospital administrators are in the process of introducing a version of the Johns Hopkins Hospital (Baltimore, Maryland) case-mix-loading cost-accumulation system. In other parts of the world they are known by other fancy names such as 'patient-costing', 'diagnosis-related-groups' (or DRGs). Trendy accounting systems seem to be the order of the day, a sort of panacea for the current plague of problems hospitals face. As the new systems become operational, however, traditional

  10. Damage Evaluation of Critical Components of Tilted Support Spring Nonlinear System under a Rectangular Pulse

    Directory of Open Access Journals (Sweden)

    Ningning Duan

    2015-01-01

    Full Text Available Dimensionless nonlinear dynamical equations of a tilted support spring nonlinear packaging system with critical components were obtained under a rectangular pulse. To evaluate the damage characteristics of shocks to packaged products with critical components, a concept of the damage boundary surface was presented and applied to a titled support spring system, with the dimensionless critical acceleration of the system, the dimensionless critical velocity, and the frequency parameter ratio of the system taken as the three basic parameters. Based on the numerical results, the effects of the frequency parameter ratio, the mass ratio, the dimensionless peak pulse acceleration, the angle of the system, and the damping ratio on the damage boundary surface of critical components were discussed. It was demonstrated that with the increase of the frequency parameter ratio, the decrease of the angle, and/or the increase of the mass ratio, the safety zone of critical components can be broadened, and increasing the dimensionless peak pulse acceleration or the damping ratio may lead to a decrease of the damage zone for critical components. The results may lead to a thorough understanding of the design principles for the tilted support spring nonlinear system.

  11. 75 FR 81264 - Critical Path Transmission, LLC; Clear Power, LLC; v. California Independent System Operator, Inc...

    Science.gov (United States)

    2010-12-27

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL11-11-000] Critical Path Transmission, LLC; Clear Power, LLC; v. California Independent System Operator, Inc.; Notice of Complaint... and 306 of the Federal Power Act, 16 U.S.C. 824e and 825e (2006), Critical Path Transmission, LLC and...

  12. 2010 Critical Success Factors for the North Carolina Community College System. Twenty First Annual Report

    Science.gov (United States)

    North Carolina Community College System (NJ1), 2010

    2010-01-01

    First mandated by the North Carolina General Assembly in 1989 (S.L. 1989; C. 752; S. 80), the Critical Success Factors report has evolved into the major accountability document for the North Carolina Community College System. This twenty first annual report on the critical success factors is the result of a process undertaken to streamline and…

  13. Blow-up Mechanism of Classical Solutions to Quasilinear Hyperbolic Systems in the Critical Case

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper deals with the blow-up phenomenon, particularly, the geometric blow-up mechanism, of classical solutions to the Cauchy problem for quasilinear hyperbolic systems in the critical case. We prove that it is still the envelope of the same family of characteristics which yields the blowup of classical solutions to the Cauchy problem in the critical case.

  14. Tank waste remediation system nuclear criticality safety inspection and assessment plan

    International Nuclear Information System (INIS)

    VAIL, T.S.

    1999-01-01

    This plan provides a management approved procedure for inspections and assessments of sufficient depth to validate that the Tank Waste Remediation System (TWRS) facility complies with the requirements of the Project Hanford criticality safety program, NHF-PRO-334, ''Criticality Safety General, Requirements''

  15. CSER 95-003: Exemption from Criticality Alarm System requirement for 232-Z building

    International Nuclear Information System (INIS)

    Nirider, L.T.; Miller, E.M.

    1995-01-01

    This CSER establishes an exemption for 232-Z from the requirement for a Criticality Alarm System, because the formation of a critical configuration is not a credible event for any circumstance involving the cleaning out and removal of the Burning Hood and associated equipment

  16. A Critical Element to Successful Implementation Of Future Safeguards Systems

    International Nuclear Information System (INIS)

    Dickman, Deborah A.

    2003-01-01

    As we look to the future of nuclear materials management and safeguards systems, it is essential to place significant emphasis on creation of a strong infrastructure to support and sustain modern systems. Traditionally, safeguards infrastructure development has focused on such elements as equipment development, strengthening of the national regulatory base, creation of state-of-the-art accounting and control systems, and procedure development. Less emphasis has been placed on recognition of the 'human element' as a primary component of the necessary infrastructure and the key to successful implementation of new or existing systems. The importance of the human element can be recognized by considering the broad span of influence and control, direction, regulation and implementation of safeguards systems exhibited by a large number of professionals: diplomats, scholars, politicians, facility managers, program directors and technical specialists. These individuals provide the connectivity or 'glue' that binds together a myriad of smaller safeguards program elements and ensures a holistic approach is fostered and maintained. The education and training of our future leaders and experts must receive the highest priority. In addition, this effort must consider factors beyond development of technical capabilities. Given the rapidly evolving world climate since the end of the cold war, our safeguards leaders and experts need education and training that will provide a well-developed understanding of the broader political dimensions of current nonproliferation challenges. They need to learn how to think, rather than what to think. A sustained effort is required to highlight the importance of the human dimension of safeguards and nuclear materials management and how these systems support international nonproliferation efforts. New educational initiatives are needed to better prepare the next generation of leaders and experts. Increased regional and national cooperation in the

  17. Key Factors for the Linkage Strategy between R and D and Commercialization for Gen-ΙV

    International Nuclear Information System (INIS)

    Lee, Kyoungmi; Hong, Jung Suk

    2013-01-01

    The Fukushima nuclear disaster has leaded to enhance the safety and the cost-effectiveness of technology for the future so that advanced countries such as United Sates and France have concerned about a next generation nuclear power plant, Gen-IV(Generation-IV Reactor). Considering various characteristics of nuclear R and D, it is necessary to have more elaborated strategies for the effective development of the next generation of nuclear technology. In this study, we suggest 5 key factors for the successful commercialization of Gen-IV by analyzing the distinct characteristics of nuclear R and D with Gen-IV and CSF(Critical Success Factor)s of several cases in these field and conducting the FGI(Focus Group Interview). Considering these results, we could find and suggest some important points for further strategy for Gen-IV. That is, following five key factors for the linkage improvement between R and D and commercialization of Gen-IV should be considered: the participation of nuclear power plant operators from the beginning, the establishment of consistent and comprehensive plan/roadmap/detailed strategy, the technology development based on global energy issues and international cooperation, the stable and clear funding plans for long-term projects, the cooperation of relative ministries. Gen-IV system is getting a positive response in that it accompanies long-term R and D plans in Korea. We think that the standard of Gen-IV would lead the next generation of nuclear industry if the proper strategy for the cooperation between the private sector and the regulation from the beginning. Moreover, we expect that this study will facilitate its development process from R and D to commercialization

  18. Key Factors for the Linkage Strategy between R and D and Commercialization for Gen-ΙV

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoungmi; Hong, Jung Suk [Korean Institute of S and T Evaluation and Planning, Seoul (Korea, Republic of)

    2013-05-15

    The Fukushima nuclear disaster has leaded to enhance the safety and the cost-effectiveness of technology for the future so that advanced countries such as United Sates and France have concerned about a next generation nuclear power plant, Gen-IV(Generation-IV Reactor). Considering various characteristics of nuclear R and D, it is necessary to have more elaborated strategies for the effective development of the next generation of nuclear technology. In this study, we suggest 5 key factors for the successful commercialization of Gen-IV by analyzing the distinct characteristics of nuclear R and D with Gen-IV and CSF(Critical Success Factor)s of several cases in these field and conducting the FGI(Focus Group Interview). Considering these results, we could find and suggest some important points for further strategy for Gen-IV. That is, following five key factors for the linkage improvement between R and D and commercialization of Gen-IV should be considered: the participation of nuclear power plant operators from the beginning, the establishment of consistent and comprehensive plan/roadmap/detailed strategy, the technology development based on global energy issues and international cooperation, the stable and clear funding plans for long-term projects, the cooperation of relative ministries. Gen-IV system is getting a positive response in that it accompanies long-term R and D plans in Korea. We think that the standard of Gen-IV would lead the next generation of nuclear industry if the proper strategy for the cooperation between the private sector and the regulation from the beginning. Moreover, we expect that this study will facilitate its development process from R and D to commercialization.

  19. Medical record management systems: criticisms and new perspectives.

    Science.gov (United States)

    Frénot, S; Laforest, F

    1999-06-01

    The first generation of computerized medical records stored the data as text, but these records did not bring any improvement in information manipulation. The use of a relational database management system (DBMS) has largely solved this problem as it allows for data requests by using SQL. However, this requires data structuring which is not very appropriate to medicine. Moreover, the use of templates and icon user interfaces has introduced a deviation from the paper-based record (still existing). The arrival of hypertext user interfaces has proven to be of interest to fill the gap between the paper-based medical record and its electronic version. We think that further improvement can be accomplished by using a fully document-based system. We present the architecture, advantages and disadvantages of classical DBMS-based and Web/DBMS-based solutions. We also present a document-based solution and explain its advantages, which include communication, security, flexibility and genericity.

  20. Biomimetics in drug delivery systems: A critical review.

    Science.gov (United States)

    Sheikhpour, Mojgan; Barani, Leila; Kasaeian, Alibakhsh

    2017-05-10

    Today, the advanced drug delivery systems have been focused on targeted drug delivery fields. The novel drug delivery is involved with the improvement of the capacity of drug loading in drug carriers, cellular uptake of drug carriers, and the sustained release of drugs within target cells. In this review, six groups of therapeutic drug carriers including biomimetic hydrogels, biomimetic micelles, biomimetic liposomes, biomimetic dendrimers, biomimetic polymeric carriers and biomimetic nanostructures, are studied. The subject takes advantage of the biomimetic methods of productions or the biomimetic techniques for the surface modifications, similar to what accrues in natural cells. Moreover, the effects of these biomimetic approaches for promoting the drug efficiency in targeted drug delivery are visible. The study demonstrates that the fabrication of biomimetic nanocomposite drug carriers could noticeably promote the efficiency of drugs in targeted drug delivery systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. A critical review of the system of radiation protection

    International Nuclear Information System (INIS)

    2000-01-01

    Our modern, information society is increasingly interested in transparency and participation in many aspects of government, and this is particularly true in areas involving public health and environmental protection. Radiation protection is no exception to this trend. Scientific rationale that was once sufficient to explain radiation protection theory and practice is no longer adequate. The need to address and communicate theory, practice and the decision-making process to a wider audience has given rise to numerous debates and led the radiation protection community to revisit the framework of the system of radiation protection. The very fundamentals of the system of radiation protection continue to be questioned in a healthy fashion, and many aspects have been identified which could better serve stakeholders given some additional thought in the light of modern societal needs. This report is the summary of the NEA's first reflections in this area, and describes those aspects of the current international system of radiation protection that could be improved. Suggested directions for improvement are provided. (author)

  2. Universal conductance and conductivity at critical points in integer quantum Hall systems.

    Science.gov (United States)

    Schweitzer, L; Markos, P

    2005-12-16

    The sample averaged longitudinal two-terminal conductance and the respective Kubo conductivity are calculated at quantum critical points in the integer quantum Hall regime. In the limit of large system size, both transport quantities are found to be the same within numerical uncertainty in the lowest Landau band, and , respectively. In the second-lowest Landau band, a critical conductance is obtained which indeed supports the notion of universality. However, these numbers are significantly at variance with the hitherto commonly believed value . We argue that this difference is due to the multifractal structure of critical wave functions, a property that should generically show up in the conductance at quantum critical points.

  3. Critical Aspects regarding the Implementation of Managerial Accounting Systems

    Directory of Open Access Journals (Sweden)

    Guinea Flavius-Andrei

    2017-01-01

    This implementation is a genuine organisational revolution that includes the managerial systemused. Any implementation process should take into account the scope of the change in mentalityand culture that the people involved should undergo. The implementation should not be made byimposing hierarchically adopted decisions, but focus on the daily contribution of each andeveryone. A new system which has not been properly internalised and accepted is doomed todisappear. The training effort should be oriented more towards the change of mentality than on thepresentation of the techniques. Within this context, putting the decisions into practice becomesextremely important, especially when it comes to studying the impact on the organisation of theleaders’ attempt to impose their vision.

  4. Non-destructive system to evaluate critical properties of asphalt compaction : [research brief].

    Science.gov (United States)

    2013-12-01

    The Wisconsin Highway Research Program sponsored a two-stage investigation to develop a non-destructive system to evaluate critical compaction properties and characteristics of asphalt pavements during the densification process. Stage One activities ...

  5. A Scalable Semantics-Based Verification System for Flight Critical Software, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Flight-critical systems rely on an ever increasing amount of software—the Boe- ing 777 contains over 2 million lines of code. Most of this code is written in the C...

  6. Providing Survivable Real-Time Communication Service for Distributed Mission Critical Systems

    National Research Council Canada - National Science Library

    Zhao, Wei; Bettati, Riccardo; Vaidya, Nitin

    2005-01-01

    This document is the final report for Providing Survivable Real-Time Communication Service for Distributed Mission Critical Systems, a Texas A AND M project funded through the DARPA Fault Tolerant Networks Program...

  7. Critical Systems Thinking for the Facilitation of Conservation Planning in Philippine Coastal Management

    NARCIS (Netherlands)

    Larsen, R.K.

    2011-01-01

    In Critical Systems Thinking, the notion of boundary judgements represents a constructionist view on knowing as the bounding of components of reality into knowable objects. Cognitive boundary judgements determine observations (facts) and evaluations (values), which knowers appreciate and act in

  8. Nonlinear Schrodinger elliptic systems involving exponential critical growth in R^2

    Directory of Open Access Journals (Sweden)

    Francisco S. B. Albuquerque Albuquerque

    2014-02-01

    Full Text Available This article concerns the existence and multiplicity of solutions for elliptic systems with weights, and nonlinearities having exponential critical growth. Our approach is based on the Trudinger-Moser inequality and on a minimax theorem.

  9. Characteristics of the French system for the detection of criticity accidents

    International Nuclear Information System (INIS)

    Barbry, F.; Prigent, R.

    1983-01-01

    The first versions of these devices were put in operation in the industry during 1976, i.e., more than 10 years after the very first criticity detection and warning systems in France. Today some 350 probes are installed

  10. A reflective lens: applying critical systems thinking and visual methods to ecohealth research.

    Science.gov (United States)

    Cleland, Deborah; Wyborn, Carina

    2010-12-01

    Critical systems methodology has been advocated as an effective and ethical way to engage with the uncertainty and conflicting values common to ecohealth problems. We use two contrasting case studies, coral reef management in the Philippines and national park management in Australia, to illustrate the value of critical systems approaches in exploring how people respond to environmental threats to their physical and spiritual well-being. In both cases, we used visual methods--participatory modeling and rich picturing, respectively. The critical systems methodology, with its emphasis on reflection, guided an appraisal of the research process. A discussion of these two case studies suggests that visual methods can be usefully applied within a critical systems framework to offer new insights into ecohealth issues across a diverse range of socio-political contexts. With this article, we hope to open up a conversation with other practitioners to expand the use of visual methods in integrated research.

  11. A Practical Risk Assessment Methodology for Safety-Critical Train Control Systems

    Science.gov (United States)

    2009-07-01

    This project proposes a Practical Risk Assessment Methodology (PRAM) for analyzing railroad accident data and assessing the risk and benefit of safety-critical train control systems. This report documents in simple steps the algorithms and data input...

  12. Year 2000 Certification of Mission-Critical DoD Information Technology Systems

    National Research Council Canada - National Science Library

    1998-01-01

    Our objective was to determine whether the year 2000 certification process is adequate to ensure that mission critical DoD information technology systems will continue to operate properly after the year 2000...

  13. Robustness of critical points in a complex adaptive system: Effects of hedge behavior

    Science.gov (United States)

    Liang, Yuan; Huang, Ji-Ping

    2013-08-01

    In our recent papers, we have identified a class of phase transitions in the market-directed resource-allocation game, and found that there exists a critical point at which the phase transitions occur. The critical point is given by a certain resource ratio. Here, by performing computer simulations and theoretical analysis, we report that the critical point is robust against various kinds of human hedge behavior where the numbers of herds and contrarians can be varied widely. This means that the critical point can be independent of the total number of participants composed of normal agents, herds and contrarians, under some conditions. This finding means that the critical points we identified in this complex adaptive system (with adaptive agents) may also be an intensive quantity, similar to those revealed in traditional physical systems (with non-adaptive units).

  14. Synthesis of Communication Schedules for TTEthernet-Based Mixed-Criticality Systems

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian; Pop, Paul; Steiner, Wilfried

    2012-01-01

    In this paper we are interested in safety-critical distributed systems, composed of heterogeneous processing elements interconnected using the TTEthernet protocol. We address hard real-time mixed-criticality applications, which may have different criticality levels, and we focus on the optimization...... be integrated onto the same architecture only if there is enough spatial and temporal separation among them. TTEthernet offers spatial separation for mixed-criticality messages through the concept of virtual links, and temporal separation, enforced through schedule tables for TT messages and bandwidth...... allocation for RC messages. Given the set of mixed-criticality messages in the system and the topology of the virtual links on which the messages are transmitted, we are interested to synthesize offline the static schedules for the TT messages, such that the deadlines for the TT and RC messages are satisfied...

  15. Measurements of Critical Heat Flux using Mass Transfer System

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seung Hyun; Chung Bum Jin [Kyunghee University, Yongin (Korea, Republic of)

    2016-05-15

    In a severe accident, the reactor vessel is heated by the decay heat from core melts and the outer surface of reactor vessel is cooled by the natural convection of water pool. When the heat flux increases, boiling will start. Further increase of the heat flux may result in the CHF, which is generated by the bubble combinations. The CHF means that the reactor vessel was separated with coolant and wall temperature is raised rapidly. It may damage the reactor vessel. Also the CHF indicates the maximum cooling capability of the system. Therefore, the CHF has been used as a criterion for the regulatory and licensing. Mechanism of hydrogen vapor bubbles generated and combined can be simulated water bubbles mechanism. And also the both heat and mass transfer mechanism of CHF can be identified in the same methods. Therefore, the CHF phenomena can be simulated enough by mass transfer.

  16. Automatic Verification of Timing Constraints for Safety Critical Space Systems

    Science.gov (United States)

    Fernandez, Javier; Parra, Pablo; Sanchez Prieto, Sebastian; Polo, Oscar; Bernat, Guillem

    2015-09-01

    In this paper is presented an automatic process of verification. We focus in the verification of scheduling analysis parameter. This proposal is part of process based on Model Driven Engineering to automate a Verification and Validation process of the software on board of satellites. This process is implemented in a software control unit of the energy particle detector which is payload of Solar Orbiter mission. From the design model is generated a scheduling analysis model and its verification model. The verification as defined as constraints in way of Finite Timed Automatas. When the system is deployed on target the verification evidence is extracted as instrumented points. The constraints are fed with the evidence, if any of the constraints is not satisfied for the on target evidence the scheduling analysis is not valid.

  17. Criticality calculations by source-collision iteration technique for cylindrical systems

    International Nuclear Information System (INIS)

    Sundaram, V.K.; Gopinath, D.V.

    1977-01-01

    A fast-converging iterative technique is presented which uses first collision probabilities developed for obtaining criticality parameters in two-region cylindrical systems with multigroup structure in energy of the neutrons. The space transmission matrix is obtained part analytically and part numerically through evaluation of a single-fold integral. Critical dimensions for condensed systems of uranium and plutonium computed using this method are presented and compared with published values

  18. Firm Size, a Self-Organized Critical Phenomenon: Evidence from the Dynamical Systems Theory

    Science.gov (United States)

    Chandra, Akhilesh

    This research draws upon a recent innovation in the dynamical systems literature called the theory of self -organized criticality (SOC) (Bak, Tang, and Wiesenfeld 1988) to develop a computational model of a firm's size by relating its internal and the external sub-systems. As a holistic paradigm, the theory of SOC implies that a firm as a composite system of many degrees of freedom naturally evolves to a critical state in which a minor event starts a chain reaction that can affect either a part or the system as a whole. Thus, the global features of a firm cannot be understood by analyzing its individual parts separately. The causal framework builds upon a constant capital resource to support a volume of production at the existing level of efficiency. The critical size is defined as the production level at which the average product of a firm's factors of production attains its maximum value. The non -linearity is inferred by a change in the nature of relations at the border of criticality, between size and the two performance variables, viz., the operating efficiency and the financial efficiency. The effect of breaching the critical size is examined on the stock price reactions. Consistent with the theory of SOC, it is hypothesized that the temporal response of a firm breaching the level of critical size should behave as a flicker noise (1/f) process. The flicker noise is characterized by correlations extended over a wide range of time scales, indicating some sort of cooperative effect among a firm's degrees of freedom. It is further hypothesized that a firm's size evolves to a spatial structure with scale-invariant, self-similar (fractal) properties. The system is said to be self-organized inasmuch as it naturally evolves to the state of criticality without any detailed specifications of the initial conditions. In this respect, the critical state is an attractor of the firm's dynamics. Another set of hypotheses examines the relations between the size and the

  19. The effect of disorder geometry on the critical force in disordered elastic systems

    International Nuclear Information System (INIS)

    Démery, Vincent; Lecomte, Vivien; Rosso, Alberto

    2014-01-01

    We address the effect of disorder geometry on the critical force in disordered elastic systems. We focus on the model system of a long-range elastic line driven in a random landscape. In the collective pinning regime, we compute the critical force perturbatively. Not only does our expression for the critical force confirm previous results on its scaling with respect to the microscopic disorder parameters, but it also provides its precise dependence on the disorder geometry (represented by the disorder two-point correlation function). Our results are successfully compared with the results of numerical simulations for random field and random bond disorders. (paper)

  20. Identification of the low-energy excitations in a quantum critical system

    Directory of Open Access Journals (Sweden)

    Tom Heitmann

    2017-05-01

    Full Text Available We have identified low-energy magnetic excitations in a doped quantum critical system by means of polarized neutron scattering experiments. The presence of these excitations could explain why Ce(Fe0.76Ru0.242Ge2 displays dynamical scaling in the absence of local critical behavior or long-range spin-density wave criticality. The low-energy excitations are associated with the reorientations of the superspins of fully ordered, isolated magnetic clusters that form spontaneously upon lowering the temperature. The system houses both frozen clusters and dynamic clusters, as predicted by Hoyos and Vojta [Phys. Rev. B 74, 140401(R (2006].

  1. Application of queueing models to multiprogrammed computer systems operating in a time-critical environment

    Science.gov (United States)

    Eckhardt, D. E., Jr.

    1979-01-01

    A model of a central processor (CPU) which services background applications in the presence of time critical activity is presented. The CPU is viewed as an M/M/1 queueing system subject to periodic interrupts by deterministic, time critical process. The Laplace transform of the distribution of service times for the background applications is developed. The use of state of the art queueing models for studying the background processing capability of time critical computer systems is discussed and the results of a model validation study which support this application of queueing models are presented.

  2. Radionuclide partitioning in environmental systems: a critical analysis

    International Nuclear Information System (INIS)

    Cremers, A.; Maes, A.

    1986-01-01

    A survey is given of some of the important processes involved in the solid-liquid distribution behaviour of radionuclides in both well-defined adsorbents and multicomponent natural systems. The thermodynamic significance of distribution coefficients is analyzed and the various parameters affecting partition behaviour are discussed in relation to possible retention mechanisms. Attention is being given to factors such as solid/liquid ratio, pH-Eh, reversibility, liquid phase composition and speciation effects. Various processes are discussed such as ion exchange and complex formation involving clays, oxides, humic acids. It is shown that, only in rare cases, Ksub(D) values can be rationalized in terms of process mechanistics. In addition, it is indicated that, in general, radionuclide distribution coefficients cannot be considered as constants unless the conditions are restricted to very small loading intervals. It is furthermore suggested that, in order to produce meaningful data on radionuclide partitioning behaviour, efforts should be made to operate under conditions which are representative for the 'in situ' situation. (author)

  3. NASA-LaRc Flight-Critical Digital Systems Technology Workshop

    Science.gov (United States)

    Meissner, C. W., Jr. (Editor); Dunham, J. R. (Editor); Crim, G. (Editor)

    1989-01-01

    The outcome is documented of a Flight-Critical Digital Systems Technology Workshop held at NASA-Langley December 13 to 15 1988. The purpose of the workshop was to elicit the aerospace industry's view of the issues which must be addressed for the practical realization of flight-critical digital systems. The workshop was divided into three parts: an overview session; three half-day meetings of seven working groups addressing aeronautical and space requirements, system design for validation, failure modes, system modeling, reliable software, and flight test; and a half-day summary of the research issues presented by the working group chairmen. Issues that generated the most consensus across the workshop were: (1) the lack of effective design and validation methods with support tools to enable engineering of highly-integrated, flight-critical digital systems, and (2) the lack of high quality laboratory and field data on system failures especially due to electromagnetic environment (EME).

  4. Diversity for security: case assessment for FPGA-based safety-critical systems

    Directory of Open Access Journals (Sweden)

    Kharchenko Vyacheslav

    2016-01-01

    Full Text Available Industrial safety critical instrumentation and control systems (I&Cs are facing more with information (in general and cyber, in particular security threats and attacks. The application of programmable logic, first of all, field programmable gate arrays (FPGA in critical systems causes specific safety deficits. Security assessment techniques for such systems are based on heuristic knowledges and the expert judgment. Main challenge is how to take into account features of FPGA technology for safety critical I&Cs including systems in which are applied diversity approach to minimize risks of common cause failure. Such systems are called multi-version (MV systems. The goal of the paper is in description of the technique and tool for case-based security assessment of MV FPGA-based I&Cs.

  5. [Medical hemostasis. II. Systemic hemostatics, a critical evaluation].

    Science.gov (United States)

    van den Bogaard, A E

    1989-02-01

    The control of spontaneous and traumatic haemorrhage is a matter of constant concern to veterinary practitioners. In some instances, the control of bleeding may be relatively simple using some topical therapeutic procedure, but when haemostatic defects are present, treatment with topical agents alone might not be sufficient, and more radical and life-saving procedures are indicated: replacement therapy with blood or blood products. As this is not easy to perform in most veterinary clinical situations, any therapeutic agent, which facilitates control of haemorrhage is a welcome addition to the therapeutic armament. Besides vitamin K, blood products and agents for topical use, there are only a few agents having a well-defined action on the mechanism of haemostasis. On the other hand several drugs are propagated in the Netherlands as systemic haemostatics in the treatment of bleeding disorders and prevention of haemorrhage during operation. None of these is of proven clinical value in veterinary practice. The only agent, which possibly showed some clinical effect: ethamsylate, has recently been withdrawn from the Dutch market by the manufacturers. Double-blind prospective trials with quantitation of loss of blood showed that antifibrinolytic agents such as tranexamic acid are clinically effective in certain conditions in humans. Because of their mode of action, it might reasonably be expected that these drugs might have positive results in veterinary medicine. Therefore, clinical trials with antifibrinolytic agents are urgently indicated to evaluate the effectiveness and side-effects of these drugs in animals showing severe bleeding or in the prevention of peroperative haemorrhage.

  6. SOME CRITICAL ASPECTS CONCERNING THE INSTITUTIONAL SYSTEM OF EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    Timofte Claudia Simona

    2013-07-01

    Full Text Available In this paper we want to clarify and understand the decisional process in European which is related to the determination of the identity of the Union, answering to several questions concerning the implementation of the European Union into an organization, the different relations with other organizations and with the international law. In the family of the international organizations, the European Union has its own place because it realizes an economic integration project and a political one, a supranational but refusing the traditional categories of constitution and the international law. Qualifying as an international organization sui generis, EU developed a new legal order, deciding to create a supranational organization, formed by Member States and their citizens. The integration process is a permanent challenge opened to a new and developing process for solving all the internal and external problems of the EU. The States have an international "sensitivity" when the application of EU rules exceeds their obligations laid down in the Treaties to third countries and international organizations to which they have not exempted obligations. It was argued that the concept of "demos" or acting people is intrinsically linked to that of the nation-State. The issue of democratic deficit of the European Union is bound to four basic problems: the construction as a whole and therefore of the institutional system, under the principle of conferral, the Union shall act only within the limits that Member States have been conferred in the Treaties to attain the objectives that they set, The Treaty of Lisbon reinforces the legitimacy of the operation of the Union based on free and democratic will expressed by Member States. European construction is achieved through a democratic transfer of competences of the democratic States to a Commission subject to a weak democratic control, while the European Central Bank preserves absolute dominion over its monetary policy

  7. Heterogeneity of critical systems as the main factor determining their radiostability

    International Nuclear Information System (INIS)

    Gudkov, I.N.

    1984-01-01

    It is shown that meristem can be considered as a convenient object for investigating regularities in the propagation kinetics of cells of critical systems and mechanisms of its regulation. Critical organs are rather perfect heterogeneous systems of automatic control where processes of their propagation and functional activity occur under strict control of spectral regulation systems to provide permanent composition and amount of cells. These systems influence purposeful cell alterations when they pass separate stages of the cell cycle. They provide the formation of funds of reserve cells and reliability of functioning of these highely sensitive organism tissues

  8. Review of battery powered embedded systems design for mission-critical low-power applications

    Science.gov (United States)

    Malewski, Matthew; Cowell, David M. J.; Freear, Steven

    2018-06-01

    The applications and uses of embedded systems is increasingly pervasive. Mission and safety critical systems relying on embedded systems pose specific challenges. Embedded systems is a multi-disciplinary domain, involving both hardware and software. Systems need to be designed in a holistic manner so that they are able to provide the desired reliability and minimise unnecessary complexity. The large problem landscape means that there is no one solution that fits all applications of embedded systems. With the primary focus of these mission and safety critical systems being functionality and reliability, there can be conflicts with business needs, and this can introduce pressures to reduce cost at the expense of reliability and functionality. This paper examines the challenges faced by battery powered systems, and then explores at more general problems, and several real-world embedded systems.

  9. A universal indicator of critical state transitions in noisy complex networked systems.

    Science.gov (United States)

    Liang, Junhao; Hu, Yanqing; Chen, Guanrong; Zhou, Tianshou

    2017-02-23

    Critical transition, a phenomenon that a system shifts suddenly from one state to another, occurs in many real-world complex networks. We propose an analytical framework for exactly predicting the critical transition in a complex networked system subjected to noise effects. Our prediction is based on the characteristic return time of a simple one-dimensional system derived from the original higher-dimensional system. This characteristic time, which can be easily calculated using network data, allows us to systematically separate the respective roles of dynamics, noise and topology of the underlying networked system. We find that the noise can either prevent or enhance critical transitions, playing a key role in compensating the network structural defect which suffers from either internal failures or environmental changes, or both. Our analysis of realistic or artificial examples reveals that the characteristic return time is an effective indicator for forecasting the sudden deterioration of complex networks.

  10. Application of an integrated PC-based neutronics code system to criticality safety

    International Nuclear Information System (INIS)

    Briggs, J.B.; Nigg, D.W.

    1991-01-01

    An integrated system of neutronics and radiation transport software suitable for operation in an IBM PC-class environment has been under development at the Idaho National Engineering Laboratory (INEL) for the past four years. Four modules within the system are particularly useful for criticality safety applications. Using the neutronics portion of the integrated code system, effective neutron multiplication values (k eff values) have been calculated for a variety of benchmark critical experiments for metal systems (Plutonium and Uranium), Aqueous Systems (Plutonium and Uranium) and LWR fuel rod arrays. A description of the codes and methods used in the analysis and the results of the benchmark critical experiments are presented in this paper. In general, excellent agreement was found between calculated and experimental results. (Author)

  11. Dynamical effects and the critical behavior of random-field systems (invited)

    International Nuclear Information System (INIS)

    Shapir, Y.

    1985-01-01

    A variety of phenomena is observed experimentally in random-field (RF) systems realized by the application of an external field to diluted antiferromagnets. At low temperatures, infinitely long hysteretic effects are manifested by the history dependence of the final states: long-range order is observed if the field is applied after cooling, while domain states are reached when field cooled. While no indications for critical fluctuations are detected in 2-D systems, scaling behavior, for both the correlation length and the specific heat, is observed in 3-D systems over an intermediate range of temperatures. The related critical properties seem to be well described by the corresponding ones in the 2-D pure Ising model. The renormalization-group approach, which yields for the equilibrium critical exponents their values of the pure model in d-2 dimensions, is reviewed. A generalization of the dimensional-reduction approach, which accounts self-consistently for renormalized responses of the RF system, is presented. The dynamical effects are implicitly incorporated through the variation in the critical response between the local and the global regimes, associated with short- and long-time scales, respectively. In both regimes the lower critical dimension is found to be d = 2 in accordance with stability arguments. The short-time critical behavior indicates a dimensional reduction by one for the 3-D thermal exponents, in agreement with the experimental results

  12. Developing thinking skill system for modelling creative thinking and critical thinking of vocational high school student

    Science.gov (United States)

    Dewanto, W. K.; Agustianto, K.; Sari, B. E.

    2018-01-01

    Vocational students must have practical skills in accordance with the purpose of vocational school that creating the skilled graduates according to their field. Graduates of vocational education are required not just as users, but be able to create. Thus requiring critical and creative thinking skills to assist students in generating ideas, analyzing and creating a product of value. Based on this, then this research aims to develop a system to know the level of ability to think critically and creative students, that resulted students can do self-reflection in improving the ability to think critically and creatively as a supporter of practical ability. The system testing using Naïve Bayes Correlation shown an average accuracy of 93.617% in assessing the students’ critical and creative thinking ability. By using modeling with this system will be known level of students’ critical and creative thinking ability, then the output of the system is used to determine the type of innovation in the learning process to improve the critical and creative thinking skills to support the practical skills of students as skilled vocational students.

  13. Dynamical effects and the critical behavior of random-field systems

    International Nuclear Information System (INIS)

    Shapir, Y.

    1985-01-01

    A variety of phenomena is observed experimentally in random-field (RF) systems realized by the application of an external field to diluted antiferromagnets. At low temperatures, infinitely long hysteretic effects are manifested by the history dependence of the final states: long-range order is observed if the field is applied after cooling, while domain states are reached when field cooled. While no indications for critical fluctuations are detected in 2-D systems, scaling behavior, for both the correlation length and the specific heat, is observed in 3-D systems over an intermediate range of temperatures. The related critical properties seem to be well described by the corresponding ones in the 2-D pure Ising model. The renormalization-group approach, which yields for the equilibrium critical exponents their values of the pure model in d-2 dimensions, is reviewed. A generalization of the dimensional-reduction approach, which accounts self-consistently for renormalized responses of the RF system, is presented. The dynamical effects are implicitly incorporated through the variation in the critical response between the local and the global regimes, associated with short- and long-time scales, respectively. In both regimes the lower critical dimension is found to be d = 2 in accordance with stability arguments. The short-time critical behavior indicates a dimensional reduction by one for the 3-D thermal exponents, in agreement with the experimental results. 37 references

  14. Use of virtual reality gaming systems for children who are critically ill.

    Science.gov (United States)

    Salem, Yasser; Elokda, Ahmed

    2014-01-01

    Children who are critically ill are frequently viewed as "too sick" to tolerate physical activity. As a result, these children often fail to develop strength or cardiovascular endurance as compared to typically developing children. Previous reports have shown that early participation in physical activity in is safe and feasible for patients who are critically ill and may result in a shorter length of stay and improved functional outcomes. The use of the virtual reality gaming systems has become a popular form of therapy for children with disabilities and has been supported by a growing body of evidence substantiating its effectiveness with this population. The use of the virtual reality gaming systems in pediatric rehabilitation provides the children with opportunity to participate in an exercise program that is fun, enjoyable, playful, and at the same time beneficial. The integration of those systems in rehabilitation of children who are critically ill is appealing and has the potential to offer the possibility of enhancing physical activities. The lack of training studies involving children who are critically ill makes it difficult to set guidelines on the recommended physical activities and virtual reality gaming systems that is needed to confer health benefits. Several considerations should be taken into account before recommended virtual reality gaming systems as a training program for children who are critically ill. This article highlighted guidelines, limitations and challenges that need to be considered when designing exercise program using virtual reality gaming systems for critically ill children. This information is helpful given the popular use of virtual reality gaming systems in rehabilitation, particularly in children who are critically ill.

  15. Preliminary Failure Modes, Effects and Criticality Analysis (FMECA) of the conceptual Brayton Isotope Power System (BIPS) Flight System

    International Nuclear Information System (INIS)

    Miller, L.G.

    1976-01-01

    A failure modes, effects and criticality analysis (FMECA) was made of the Brayton Isotope Power System Flight System (BIPS-FS) as presently conceived. The components analyzed include: Mini-BRU; Heat Source Assembly (HSA); Mini-Brayton Recuperator (MBR); Space Radiator; Ducts and Bellows, Insulation System; Controls; and Isotope Heat Source (IHS)

  16. Thermal properties of ionic systems near the liquid-liquid critical point.

    Science.gov (United States)

    Méndez-Castro, Pablo; Troncoso, Jacobo; Pérez-Sánchez, Germán; Peleteiro, José; Romaní, Luis

    2011-12-07

    Isobaric heat capacity per unit volume, C(p), and excess molar enthalpy, h(E), were determined in the vicinity of the critical point for a set of binary systems formed by an ionic liquid and a molecular solvent. Moreover, and, since critical composition had to be accurately determined, liquid-liquid equilibrium curves were also obtained using a calorimetric method. The systems were selected with a view on representing, near room temperature, examples from clearly solvophobic to clearly coulombic behavior, which traditionally was related with the electric permittivity of the solvent. The chosen molecular compounds are: ethanol, 1-butanol, 1-hexanol, 1,3-dichloropropane, and diethylcarbonate, whereas ionic liquids are formed by imidazolium-based cations and tetrafluoroborate or bis-(trifluromethylsulfonyl)amide anions. The results reveal that solvophobic critical behavior-systems with molecular solvents of high dielectric permittivity-is very similar to that found for molecular binary systems. However, coulombic systems-those with low permittivity molecular solvents-show strong deviations from the results usually found for these magnitudes near the liquid-liquid phase transition. They present an extremely small critical anomaly in C(p)-several orders of magnitude lower than those typically obtained for binary mixtures-and extremely low h(E)-for one system even negative, fact not observed, up to date, for any liquid-liquid transition in the nearness of an upper critical solution temperature. © 2011 American Institute of Physics

  17. Bibliography for nuclear criticality accident experience, alarm systems, and emergency management

    International Nuclear Information System (INIS)

    Putman, V.L.

    1995-09-01

    The characteristics, detection, and emergency management of nuclear criticality accidents outside reactors has been an important component of criticality safety for as long as the need for this specialized safety discipline has been recognized. The general interest and importance of such topics receives special emphasis because of the potentially lethal, albeit highly localized, effects of criticality accidents and because of heightened public and regulatory concerns for any undesirable event in nuclear and radiological fields. This bibliography lists references which are potentially applicable to or interesting for criticality alarm, detection, and warning systems; criticality accident emergency management; and their associated programs. The lists are annotated to assist bibliography users in identifying applicable: industry and regulatory guidance and requirements, with historical development information and comments; criticality accident characteristics, consequences, experiences, and responses; hazard-, risk-, or safety-analysis criteria; CAS design and qualification criteria; CAS calibration, maintenance, repair, and testing criteria; experiences of CAS designers and maintainers; criticality accident emergency management (planning, preparedness, response, and recovery) requirements and guidance; criticality accident emergency management experience, plans, and techniques; methods and tools for analysis; and additional bibliographies

  18. Critical heat flux and exit film flow rate in a flow boiling system

    International Nuclear Information System (INIS)

    Ueda, Tatsuhiro; Isayama, Yasushi

    1981-01-01

    The critical heat flux in a flowing boiling system is an important problem in the evaporating tubes with high thermal load such as nuclear reactors and boilers, and gives the practical design limit. When the heat flux in uniformly heated evaporating tubes is gradually raised, the tube exit quality increases, and soon, the critical heat flux condition arises, and the wall temperature near tube exit rises rapidly. In the region of low exit quality, the critical heat flux condition is caused by the transition from nucleating boiling, and in the region of high exit quality, it is caused by dry-out. But the demarcation of both regions is not clear. In this study, for the purpose of obtaining the knowledge concerning the critical heat flux condition in a flowing boiling system, the relation between the critical heat flux and exit liquid film flow rate was examined. For the experiment, a uniformly heated vertical tube supplying R 113 liquid was used, and the measurement in the range of higher heating flux and mass velocity than the experiment by Ueda and Kin was carried out. The experimental setup and experimental method, the critical heat flux and exit quality, the liquid film flow rate at heating zone exit, and the relation between the critical heat flux and the liquid film flow rate at exit are described. (Kako, I.)

  19. Critical and subcritical parameters of the system simulating plutonium metal dissolution

    International Nuclear Information System (INIS)

    Vasilev, Yury Yu.; Ryazanov, Boris G.; Sviridov, Victor I.; Mozhayeva, Lubov I.

    2003-01-01

    Dissolution of plutonium metal was simulated using the Monte Carlo computer code to calculate criticality safety limits for the process. Calculations were made for the constant masses of plutonium charged to the dissolving vessel considering distribution of plutonium in metal and solution phases. Critical parameters and limits were calculated as a function of dissolving vessel volume and plutonium metal mass. 240 Pu content was assumed to be from 0% to 10% (mass). Critical parameters were evaluated for the system with a water reflector. Results of this paper may be used in the designing process equipment for plutonium metal dissolution. (author)

  20. Network Attack Detection and Defense: Securing Industrial Control Systems for Critical Infrastructures (Dagstuhl Seminar 14292)

    NARCIS (Netherlands)

    Dacer, Marc; Kargl, Frank; König, Hartmut; Valdes, Alfonso

    2014-01-01

    This report documents the program and the outcomes of Dagstuhl Seminar 14292 “Network Attack Detection and Defense: Securing Industrial Control Systems for Critical Infrastructures”. The main objective of the seminar was to discuss new approaches and ideas for securing industrial control systems. It

  1. Extending a real-time operating system with a mechanism for criticality-level changes

    NARCIS (Netherlands)

    Gupta, T.

    2015-01-01

    Systems robustness, cost reduction and certification play an important role in the automotive domain. If there is a fault, e.g. task overshooting its allocated execution time, sufficient mechanisms should be available to safeguard the system against those. Applications of different criticalities

  2. Estimating Impact and Frequency of Risks to Safety and Mission Critical Systems Using CVSS

    NARCIS (Netherlands)

    Houmb, S.H.; Nunes Leal Franqueira, V.; Engum, E.A.

    2008-01-01

    Many safety and mission critical systems depend on the correct and secure operation of both supportive and core software systems. E.g., both the safety of personnel and the effective execution of core missions on an oil platform depend on the correct recording storing, transfer and interpretation of

  3. Algorithm for preparation of multilayer systems with high critical angle of total reflection

    International Nuclear Information System (INIS)

    Carron, I.; Ignatovich, V.

    2002-01-01

    The new development of theory of multilayer systems is presented. It shows precisely how to calculate thickness and number of layers to get reflectivity close to unity for a given, in principle, arbitrary critical angle. Application of the new approach to real systems is demonstrated

  4. Reliability analysis of scram system of a critical nuclear power plant

    International Nuclear Information System (INIS)

    Vieira Neto, A.S.; Souza Borges, W. de

    1986-01-01

    The object of this paper is to show the relevancy of reliability analysis of nuclear systems as a mean of evaluating their prospect performance in design phase. For this purpose a typical scram system design for light water cooled critical facilities is analized to verify the effects of alternative maintenance procedure and design redundancies in realibility characteristics. (Author) [pt

  5. Critical control points for the management of microbial growth in HVAC systems

    NARCIS (Netherlands)

    Gommers, S; Franchimon, F.; Bronswijk, van J.E.M.H.; Strøm-Tejsen, P; Olesen, BW; Wargocki, P; Zukowska, D; Toftum, J

    2008-01-01

    Office buildings with HVAC systems consistently report Sick Building Symptoms that are derived from microbial growth. We used the HACCP methodology to find the main critical control points (CCPs) for microbial management of HVAC systems in temperate climates. Desk research revealed relative humidity

  6. Inner-Resonance Conditions for Honeycomb Paperboard Cushioning Packaging System with Critical Component

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2013-01-01

    Full Text Available A dynamic model was proposed for a honeycomb paperboard cushioning packaging system with critical component. Then the coupled equations of the system were solved by the variational iteration method, from which the conditions for inner-resonance were obtained, which should be avoided in the cushioning packaging design.

  7. Vulnerability analysis and critical areas identification of the power systems under terrorist attacks

    Science.gov (United States)

    Wang, Shuliang; Zhang, Jianhua; Zhao, Mingwei; Min, Xu

    2017-05-01

    This paper takes central China power grid (CCPG) as an example, and analyzes the vulnerability of the power systems under terrorist attacks. To simulate the intelligence of terrorist attacks, a method of critical attack area identification according to community structures is introduced. Meanwhile, three types of vulnerability models and the corresponding vulnerability metrics are given for comparative analysis. On this basis, influence of terrorist attacks on different critical areas is studied. Identifying the vulnerability of different critical areas will be conducted. At the same time, vulnerabilities of critical areas under different tolerance parameters and different vulnerability models are acquired and compared. Results show that only a few number of vertex disruptions may cause some critical areas collapse completely, they can generate great performance losses the whole systems. Further more, the variation of vulnerability values under different scenarios is very large. Critical areas which can cause greater damage under terrorist attacks should be given priority of protection to reduce vulnerability. The proposed method can be applied to analyze the vulnerability of other infrastructure systems, they can help decision makers search mitigation action and optimum protection strategy.

  8. Criticality parameters for uranyl nitrate or plutonium nitrate systems in tributyl phosphate/kerosine and water

    International Nuclear Information System (INIS)

    Weber, W.

    1985-01-01

    This report presents the calculated values of smallest critical masses and volumina and neutron physical parameters for uranyl nitrate (3, 4, 5% U-235) or plutonium nitrate (5% Pu-240), each in a 30 per cent solution of tributyl phosphate (TBP)/kerosine. For the corresponding nitrate-water solutions, newly calculated results are presented together with a revised solution density model. A comparison of the data shows to what extent the criticality of nitrate-TBP/kerosine systems can be assessed on the basis of nitrate-water parameters, revealing that such data can be applied to uranyl nitrate/water systems, taking into account that the smallest critical mass of uranyl nitrate-TBP/kerosine systems, up to a 5 p.c. U-235 enrichment, is by 4.5 p.c. at the most smaller than that of UNH-water solutions. Plutonium nitrate (5% Pu-240) in the TBP/kerosine solution will have a smallest critical mass of up to 7 p.c. smaller, as compared with the water data. The suitability of the computing methods and cross-sections used is verified by recalculating experiments carried out to determine the lowest critical enrichment of uranyl nitrate. The calculated results are well in agreement with experimental data. The lowest critical enrichment is calculated to be 2.10 p.c. in the isotope U-235. (orig.) [de

  9. Determination of Critical Parameters of Carbon Dioxide+ Butyraldehyde System with Different Compositions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-chang; GAO Xi-xin; CAO Wei-liang

    2005-01-01

    Supercritical carbon dioxide( SC-CO2 ) is considered in green chemistry as a substitute for conventional solvents in chemical reactions due to its environmentally benign character. Recently we have reported the homogeneous hydroformylation of propylene in supercritical carbon dioxide( SC-CO2 ), which is an example of this kind of application of carbon dioxide. The determination for the critical parameters of carbon dioxide + butyraldehyde mixtures is necessary for this reaction design which is the focus of the present paper. The critical parameters of the binary systems were determined via the static visual method at a constant volume with the molar fraction of butyraldehyde ranging from 1.0%to 2. 2% and the pressure ranging from 5 to 10 MPa. The experimental results show that the critical pressure and temperature increased with increasing the molar fraction of butyraldehyde. The bubble(dew) temperatures and the bubble (dew) pressures for the binary systems were also determined experimentally. The p-T Figures at different compositions of the binary systems were described. In addition, the critical compressibility factors Zc of the binary systems at different concentrations of n-butyraldehyde were calculated. It was found that the critical compressibility factor values of the binary systems decreased with increasing the molar fraction of n-butyraldehyde in the experimental range.

  10. Quantum criticality around metal-insulator transitions of strongly correlated electron systems

    Science.gov (United States)

    Misawa, Takahiro; Imada, Masatoshi

    2007-03-01

    Quantum criticality of metal-insulator transitions in correlated electron systems is shown to belong to an unconventional universality class with violation of the Ginzburg-Landau-Wilson (GLW) scheme formulated for symmetry breaking transitions. This unconventionality arises from an emergent character of the quantum critical point, which appears at the marginal point between the Ising-type symmetry breaking at nonzero temperatures and the topological transition of the Fermi surface at zero temperature. We show that Hartree-Fock approximations of an extended Hubbard model on square lattices are capable of such metal-insulator transitions with unusual criticality under a preexisting symmetry breaking. The obtained universality is consistent with the scaling theory formulated for Mott transitions and with a number of numerical results beyond the mean-field level, implying that preexisting symmetry breaking is not necessarily required for the emergence of this unconventional universality. Examinations of fluctuation effects indicate that the obtained critical exponents remain essentially exact beyond the mean-field level. It further clarifies the whole structure of singularities by a unified treatment of the bandwidth-control and filling-control transitions. Detailed analyses of the criticality, containing diverging carrier density fluctuations around the marginal quantum critical point, are presented from microscopic calculations and reveal the nature as quantum critical “opalescence.” The mechanism of emerging marginal quantum critical point is ascribed to a positive feedback and interplay between the preexisting gap formation present even in metals and kinetic energy gain (loss) of the metallic carrier. Analyses of crossovers between GLW type at nonzero temperature and topological type at zero temperature show that the critical exponents observed in (V,Cr)2O3 and κ-ET -type organic conductors provide us with evidence for the existence of the present marginal

  11. Design Information from the PSA for Digital Safety-Critical Systems

    International Nuclear Information System (INIS)

    Kang, Hyun Gook; Jang, Seung Cheol

    2005-01-01

    Many safety-critical applications such as nuclear field application usually adopt a similar design strategy for digital safety-critical systems. Their differences from the normal design for the non-safety-critical applications could be summarized as: multiple-redundancy, highly reliable components, strengthened monitoring mechanism, verified software, and automated test procedure. These items are focusing on maintaining the capability to perform the given safety function when it is requested. For the past several decades, probabilistic safety assessment (PSA) techniques are used in the nuclear industry to assess the relative effects of contributing events on plant risk and system reliability. They provide a unifying means of assessing physical faults, recovery processes, contributing effects, human actions, and other events that have a high degree of uncertainty. The applications of PSA provide not only the analysis results of already installed system but also the useful information for the system under design. The information could be derived from the PSA experience of the various safety-critical systems. Thanks to the design flexibility, the digital system is one of the most suitable candidates for risk-informed design (RID). In this article, we will describe the feedbacks for system design and try to develop a procedure for RID. Even though the procedure is not sophisticated enough now, it could be the start point of the further investigation for developing more complete and practical methodology

  12. Maintaining scale as a realiable computational system for criticality safety analysis

    International Nuclear Information System (INIS)

    Bowmann, S.M.; Parks, C.V.; Martin, S.K.

    1995-01-01

    Accurate and reliable computational methods are essential for nuclear criticality safety analyses. The SCALE (Standardized Computer Analyses for Licensing Evaluation) computer code system was originally developed at Oak Ridge National Laboratory (ORNL) to enable users to easily set up and perform criticality safety analyses, as well as shielding, depletion, and heat transfer analyses. Over the fifteen-year life of SCALE, the mainstay of the system has been the criticality safety analysis sequences that have featured the KENO-IV and KENO-V.A Monte Carlo codes and the XSDRNPM one-dimensional discrete-ordinates code. The criticality safety analysis sequences provide automated material and problem-dependent resonance processing for each criticality calculation. This report details configuration management which is essential because SCALE consists of more than 25 computer codes (referred to as modules) that share libraries of commonly used subroutines. Changes to a single subroutine in some cases affect almost every module in SCALE exclamation point Controlled access to program source and executables and accurate documentation of modifications are essential to maintaining SCALE as a reliable code system. The modules and subroutine libraries in SCALE are programmed by a staff of approximately ten Code Managers. The SCALE Software Coordinator maintains the SCALE system and is the only person who modifies the production source, executables, and data libraries. All modifications must be authorized by the SCALE Project Leader prior to implementation

  13. Conceptual design of a digital control system for nuclear criticality experiments

    International Nuclear Information System (INIS)

    Rojas, S.P.

    1994-04-01

    Nuclear criticality is a concern in many areas of nuclear engineering including waste management, nuclear weapons testing and design, basic nuclear research, and nuclear reactor design and analysis. As in many areas of science and engineering, experimental work conducted in this field has provided a wealth of data and insight essential to the formulation of theory and the advancement in knowledge of fissioning systems. In light of the many diverse applications of nuclear criticality, there is a continuing interest to learn and understand more about the fundamental physical processes through continued experimentation. This thesis addresses the problem of setting up and programming a microprocessor-based digital control system (PLC) for a proposed critical experiment using, among other devices, a stepper motor, a joystick control mechanism, and switches. This experiment represents a revised configuration to test cylindrical nuclear waste packages. A Monte Carlo numerical study for the proposed critical assembly has been performed in order to illustrate how results from numerical calculations are used in the process of assembling the control system and to corroborate previous experimental data. In summary, a control system utilizing some common devices necessary to perform a critical experiment (stepper motor, push-buttons, etc.) has been assembled. Control components were sized using the results of a probabilistic computer code (MCNP). Finally, a program was written that illustrates the coupling between the hardware and the devices being controlled in the new test fixture

  14. Systems of transversal sections near critical energy levels of hamiltonian systems in $Mathbb{R}^{4}$

    CERN Document Server

    de, Naiara V

    2018-01-01

    In this article the authors study Hamiltonian flows associated to smooth functions H:\\mathbb R^4 \\to \\mathbb R restricted to energy levels close to critical levels. They assume the existence of a saddle-center equilibrium point p_c in the zero energy level H^{-1}(0). The Hamiltonian function near p_c is assumed to satisfy Moser's normal form and p_c is assumed to lie in a strictly convex singular subset S_0 of H^{-1}(0). Then for all E \\gt 0 small, the energy level H^{-1}(E) contains a subset S_E near S_0, diffeomorphic to the closed 3-ball, which admits a system of transversal sections \\mathcal F_E, called a 2-3 foliation. \\mathcal F_E is a singular foliation of S_E and contains two periodic orbits P_2,E\\subset \\partial S_E and P_3,E\\subset S_E\\setminus \\partial S_E as binding orbits. P_2,E is the Lyapunoff orbit lying in the center manifold of p_c, has Conley-Zehnder index 2 and spans two rigid planes in \\partial S_E. P_3,E has Conley-Zehnder index 3 and spans a one parameter family of planes in S_E \\setmin...

  15. Critical and precious materials consumption and requirement in wind energy system in the EU 27

    International Nuclear Information System (INIS)

    Kim, Junbeum; Guillaume, Bertrand; Chung, Jinwook; Hwang, Yongwoo

    2015-01-01

    Graphical abstract: Critical and precious materials requirement in the wind energy system in the EU 27 by 2020. - Highlights: • The critical and precious materials consumption were calculated in wind energy system in the EU 27. • The future requirement of critical and precious materials was estimated in the EU 27 by 2020. • Fluorspar, silver, magnesium, indium, gold and tantalum are the mainly used and required materials. • This research approach could be applied to other industrial sectors as well as other renewable technology. - Abstract: Critical materials as well as rare earth elements and precious metals such as platinum, gold and silver are used significantly for computer hard disk drives, mobile phones, hybrid electric vehicles, batteries, renewable energy system and many other applications. It is therefore important to quantify and estimate both current stocks and flows of such materials, as well as future requirement for industries and economies. In this study, which is focused on wind energy system in the European Union (EU) 27, the current consumption and future requirement of critical and precious materials were calculated and estimated using the wind power production dataset from ecoinvent and data from National Renewable Energy Action Plan (NREAP). It is shown that fluorspar has been the most consumed material to date, and will probably be the most required material in the future. Among other critical and valuable materials, the main materials used for current wind energy system are silver, magnesium, indium, gold and tantalum. These materials will also be required significantly by 2020 for the wind energy system in the EU 27. It is argued that these results should be connected to the future energy and material policy and management

  16. Experimental and Numerical Analysis of S-CO2 Critical Flow for SFR Recovery System Design

    International Nuclear Information System (INIS)

    Kim, Min Seok; Jung, Hwa-Young; Ahn, Yoonhan; Lee, Jekyoung; Lee, Jeong Ik

    2016-01-01

    This paper presents both numerical and experimental studies of the critical flow of S-CO 2 while special attention is given to the turbo-machinery seal design. A computational critical flow model is described first. The experiments were conducted to validate the critical flow model. Various conditions have been tested to study the flow characteristic and provide validation data for the model. The comparison of numerical and experimental results of S-CO 2 critical flow will be presented. In order to eliminate SWR, a concept of coupling the Supercritical CO 2 (S-CO 2 ) cycle with SFR has been proposed. It is known that for a closed system controlling the inventory is important for stable operation and achieving high efficiency. Since the S-CO 2 power cycle is a highly pressurized system, certain amount of leakage flow is inevitable in the rotating turbo-machinery via seals. To simulate the CO 2 leak flow in a turbo-machinery with higher accuracy in the future, the real gas effect and friction factor will be considered for the CO 2 critical flow model. Moreover, experimentally obtained temperature data were somewhat different from the numerically obtained temperature due to the insufficient insulation and large thermal inertia of the CO 2 critical flow facility. Insulation in connecting pipes and the low-pressure tank will be added and additional tests will be conducted

  17. Critical success factors for implementing supply chain information systems : insights from the pork industry

    OpenAIRE

    Denolf, J.M.

    2014-01-01

    Critical success factors for implementing supply chain information systems – Janne M. Denolf Due to intensified competition, companies realize that they should closely collaborate with their supply-chain partners to further cut costs and stay competitive. To do so, supply-chain partners should intensify information sharing, which is often facilitated through supply chain information systems (SCIS). Implementation of such a system is a complex undertaking due to the umpteen technical and organ...

  18. R and D study on on-line criticality surveillance system (V)

    International Nuclear Information System (INIS)

    Yamada, Sumasu

    2001-02-01

    In view of necessity and importance of criticality surveillance systems for ensuring the safety of nuclear fuel manufacturing and reprocessing plants, 5-year basic studies and 4 year R and D studies on an on-line criticality surveillance system were carried out since 1991. This report is a summary of these series of studies. Noticing that the signal from a neutron detector is random in principle, these series of studies aimed to accumulate knowledge for developing an inexpensive criticality surveillance system with quick response based on the Auto-Regressive Moving Average (ARMA) model identification algorithm. During five-year basic studies on criticality surveillance system since 1991, we obtained knowledge required for developing a criticality surveillance system based on the ARMA model identification algorithm through 1) studies on recursive ARMA model identification algorithms most appropriate for estimating subcriticality form time series data under a steady state condition, 2) studies on pre-processing of signal from neutron detectors, 3) developing a new recursive ARMA model identification algorithm with small time delay to estimate time-dependent subcriticality, 4) proposing a basic concept for the elements required for an on-line criticality surveillance system, and 5) numerical analysis of data from the DCA experiments. During next four-year R and D studies on a criticality surveillance system since 1996, we 1) proposed modules required for a no-line criticality surveillance system, 2) revealed effectiveness of a adaptive digital filter (ADF) algorithm, as an important redundancy to the recursive ARMA model identification algorithm to be used in the signal processing module through numerical analysis of real data, 3) proposed a module of the Feynman-α method over γ ray signal and a fast signal processing module for γ ray signal, 4) developed a line-noise removal filter(Notch filter) and revealed its effectiveness for the DCA data corrupted with power

  19. Tests of HAMMER (original) and HAMMER-TECHNION systems with critical experiments

    International Nuclear Information System (INIS)

    Santos, A. dos

    1986-01-01

    Performances of the reactor cell codes HAMMER (original) and HAMMER-TECHNION were tested against experimental results of critical benchmarks. The option made was the utilization of consistent methodologies so that only the NIT (Nordheim Integral Technique) was utilized in the HAMMER-TECHNION. All differences encountered in the analysis made with these systems can be attributed to their basic nuclear data library. Five critical benchmarks was utilized on this study. Surprisingly, the performance of the original HAMMER system was betterthan that of the HAMMER-TECHNION. (Author) [pt

  20. A framework for modeling information propagation of biological systems at critical states.

    Science.gov (United States)

    Hu, Feng; Yang, Fang

    2016-03-01

    We explore the dynamics of information propagation at the critical state of a biologically inspired system by an individual-based computer model. "Quorum response", a type of social interaction which has been recognized taxonomically in animal groups, is applied as the sole interaction rule among individuals. In the model, we assume a truncated Gaussian distribution to depict the distribution of the individuals' vigilance level. Each individual can assume either a naïve state or an alarmed one and only switches from the former state to the latter one. If an individual has turned into an alarmed state, it stays in the state during the process of information propagation. Initially, each individual is set to be at the naïve state and information is tapped into the system by perturbing an individual at the boundaries (alerting it to the alarmed state). The system evolves as individuals turn into the alarmed state, according to the quorum response rules, consecutively. We find that by fine-tuning the parameters of the mean and the standard deviation of the Gaussian distribution, the system is poised at a critical state. We present the phase diagrams to exhibit that the parameter space is divided into a super-critical and a sub-critical zone, in which the dynamics of information propagation varies largely. We then investigate the effects of the individuals' mobility on the critical state, and allow a proportion of randomly chosen individuals to exchange their positions at each time step. We find that mobility breaks down criticality of the system. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. Clustering analysis of water distribution systems: identifying critical components and community impacts.

    Science.gov (United States)

    Diao, K; Farmani, R; Fu, G; Astaraie-Imani, M; Ward, S; Butler, D

    2014-01-01

    Large water distribution systems (WDSs) are networks with both topological and behavioural complexity. Thereby, it is usually difficult to identify the key features of the properties of the system, and subsequently all the critical components within the system for a given purpose of design or control. One way is, however, to more explicitly visualize the network structure and interactions between components by dividing a WDS into a number of clusters (subsystems). Accordingly, this paper introduces a clustering strategy that decomposes WDSs into clusters with stronger internal connections than external connections. The detected cluster layout is very similar to the community structure of the served urban area. As WDSs may expand along with urban development in a community-by-community manner, the correspondingly formed distribution clusters may reveal some crucial configurations of WDSs. For verification, the method is applied to identify all the critical links during firefighting for the vulnerability analysis of a real-world WDS. Moreover, both the most critical pipes and clusters are addressed, given the consequences of pipe failure. Compared with the enumeration method, the method used in this study identifies the same group of the most critical components, and provides similar criticality prioritizations of them in a more computationally efficient time.

  2. Analysis of strain distribution and critical current of superconductors based on a strain-critical current measurement system

    International Nuclear Information System (INIS)

    Liu Fang; Wu Yu; Long Feng

    2010-01-01

    Based on Pacman device which is widely used to investigate the axial strain dependence of the critical current in superconductors, the finite element analysis method is employed to carry out the force analysis of the spring and the superconducting strand, thereby the axial and lateral strain distributions of the superconducting strand are obtained. According to the two extreme assumptions(low inter-filament resistance and high inter-filament resistance), the effects of the strain homogeneity at the cross section of the superconductor on the critical current is analyzed combined with the Nb 3 Sn deviatoric strain-critical current scaling law. (authors)

  3. Modeling of requirement specification for safety critical real time computer system using formal mathematical specifications

    International Nuclear Information System (INIS)

    Sankar, Bindu; Sasidhar Rao, B.; Ilango Sambasivam, S.; Swaminathan, P.

    2002-01-01

    Full text: Real time computer systems are increasingly used for safety critical supervision and control of nuclear reactors. Typical application areas are supervision of reactor core against coolant flow blockage, supervision of clad hot spot, supervision of undesirable power excursion, power control and control logic for fuel handling systems. The most frequent cause of fault in safety critical real time computer system is traced to fuzziness in requirement specification. To ensure the specified safety, it is necessary to model the requirement specification of safety critical real time computer systems using formal mathematical methods. Modeling eliminates the fuzziness in the requirement specification and also helps to prepare the verification and validation schemes. Test data can be easily designed from the model of the requirement specification. Z and B are the popular languages used for modeling the requirement specification. A typical safety critical real time computer system for supervising the reactor core of prototype fast breeder reactor (PFBR) against flow blockage is taken as case study. Modeling techniques and the actual model are explained in detail. The advantages of modeling for ensuring the safety are summarized

  4. An Improved Method to Control the Critical Parameters of a Multivariable Control System

    Science.gov (United States)

    Subha Hency Jims, P.; Dharmalingam, S.; Wessley, G. Jims John

    2017-10-01

    The role of control systems is to cope with the process deficiencies and the undesirable effect of the external disturbances. Most of the multivariable processes are highly iterative and complex in nature. Aircraft systems, Modern Power Plants, Refineries, Robotic systems are few such complex systems that involve numerous critical parameters that need to be monitored and controlled. Control of these important parameters is not only tedious and cumbersome but also is crucial from environmental, safety and quality perspective. In this paper, one such multivariable system, namely, a utility boiler has been considered. A modern power plant is a complex arrangement of pipework and machineries with numerous interacting control loops and support systems. In this paper, the calculation of controller parameters based on classical tuning concepts has been presented. The controller parameters thus obtained and employed has controlled the critical parameters of a boiler during fuel switching disturbances. The proposed method can be applied to control the critical parameters like elevator, aileron, rudder, elevator trim rudder and aileron trim, flap control systems of aircraft systems.

  5. Initial conceptual design study of self-critical nuclear pumped laser systems

    Science.gov (United States)

    Rodgers, R. J.

    1979-01-01

    An analytical study of self-critical nuclear pumped laser system concepts was performed. Primary emphasis was placed on reactor concepts employing gaseous uranium hexafluoride (UF6) as the fissionable material. Relationships were developed between the key reactor design parameters including reactor power level, critical mass, neutron flux level, reactor size, operating pressure, and UF6 optical properties. The results were used to select a reference conceptual laser system configuration. In the reference configuration, the 3.2 m cubed lasing volume is surrounded by a graphite internal moderator and a region of heavy water. Results of neutronics calculations yield a critical mass of 4.9 U(235) in the form (235)UF6. The configuration appears capable of operating in a continuous steady-state mode. The average gas temperature in the core is 600 K and the UF6 partial pressure within the lasing volume is 0.34 atm.

  6. Critical Characteristics of Radiation Detection System Components to be Dedicated for use in Safety Class and Safety Significant System

    International Nuclear Information System (INIS)

    DAVIS, S.J.

    2000-01-01

    This document identifies critical characteristics of components to be dedicated for use in Safety Significant (SS) Systems, Structures, or Components (SSCs). This document identifies the requirements for the components of the common, radiation area, monitor alarm in the WESF pool cell. These are procured as Commercial Grade Items (CGI), with the qualification testing and formal dedication to be performed at the Waste Encapsulation Storage Facility (WESF) for use in safety significant systems. System modifications are to be performed in accordance with the approved design. Components for this change are commercially available and interchangeable with the existing alarm configuration This document focuses on the operational requirements for alarm, declaration of the safety classification, identification of critical characteristics, and interpretation of requirements for procurement. Critical characteristics are identified herein and must be verified, followed by formal dedication, prior to the components being used in safety related applications

  7. Masters Thesis- Criticality Alarm System Design Guide with Accompanying Alarm System Development for the Radioisotope Production Laboratory in Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Greenfield, Bryce A. [Univ. of New Mexico, Albuquerque, NM (United States)

    2009-12-01

    A detailed instructional manual was created to guide criticality safety engineers through the process of designing a criticality alarm system (CAS) for Department of Energy (DOE) hazard class 1 and 2 facilities. Regulatory and technical requirements were both addressed. A list of design tasks and technical subtasks are thoroughly analyzed to provide concise direction for how to complete the analysis. An example of the application of the design methodology, the Criticality Alarm System developed for the Radioisotope Production Laboratory (RPL) of Richland, Washington is also included. The analysis for RPL utilizes the Monte Carlo code MCNP5 for establishing detector coverage in the facility. Significant improvements to the existing CAS were made that increase the reliability, transparency, and coverage of the system.

  8. Supervisory Control and Data Acquisition (SCADA) Systems and Cyber-Security: Best Practices to Secure Critical Infrastructure

    Science.gov (United States)

    Morsey, Christopher

    2017-01-01

    In the critical infrastructure world, many critical infrastructure sectors use a Supervisory Control and Data Acquisition (SCADA) system. The sectors that use SCADA systems are the electric power, nuclear power and water. These systems are used to control, monitor and extract data from the systems that give us all the ability to light our homes…

  9. Neonatal and pediatric regionalized systems in pediatric emergency mass critical care.

    Science.gov (United States)

    Barfield, Wanda D; Krug, Steven E; Kanter, Robert K; Gausche-Hill, Marianne; Brantley, Mary D; Chung, Sarita; Kissoon, Niranjan

    2011-11-01

    Improved health outcomes are associated with neonatal and pediatric critical care in well-organized, cohesive, regionalized systems that are prepared to support and rehabilitate critically ill victims of a mass casualty event. However, present systems lack adequate surge capacity for neonatal and pediatric mass critical care. In this document, we outline the present reality and suggest alternative approaches. In May 2008, the Task Force for Mass Critical Care published guidance on provision of mass critical care to adults. Acknowledging that the critical care needs of children during disasters were unaddressed by this effort, a 17-member Steering Committee, assembled by the Oak Ridge Institute for Science and Education with guidance from members of the American Academy of Pediatrics, convened in April 2009 to determine priority topic areas for pediatric emergency mass critical care recommendations.Steering Committee members established subcommittees by topic area and performed literature reviews of MEDLINE and Ovid databases. The Steering Committee produced draft outlines through consensus-based study of the literature and convened October 6-7, 2009, in New York, NY, to review and revise each outline. Eight draft documents were subsequently developed from the revised outlines as well as through searches of MEDLINE updated through March 2010.The Pediatric Emergency Mass Critical Care Task Force, composed of 36 experts from diverse public health, medical, and disaster response fields, convened in Atlanta, GA, on March 29-30, 2010. Feedback on each manuscript was compiled and the Steering Committee revised each document to reflect expert input in addition to the most current medical literature. States and regions (facilitated by federal partners) should review current emergency operations and devise appropriate plans to address the population-based needs of infants and children in large-scale disasters. Action at the state, regional, and federal levels should address

  10. Cooperation, competition and the emergence of criticality in communities of adaptive systems

    International Nuclear Information System (INIS)

    Hidalgo, Jorge; Muñoz, Miguel A; Grilli, Jacopo; Suweis, Samir; Maritan, Amos

    2016-01-01

    The hypothesis that living systems can benefit from operating at the vicinity of critical points has gained momentum in recent years. Criticality may confer an optimal balance between too ordered and exceedingly noisy states. Here we present a model, based on information theory and statistical mechanics, illustrating how and why a community of agents aimed at understanding and communicating with each other converges to a globally coherent state in which all individuals are close to an internal critical state, i.e. at the borderline between order and disorder. We study—both analytically and computationally—the circumstances under which criticality is the best possible outcome of the dynamical process, confirming the convergence to critical points under very generic conditions. Finally, we analyze the effect of cooperation (agents trying to enhance not only their fitness, but also that of other individuals) and competition (agents trying to improve their own fitness and to diminish those of competitors) within our setting. The conclusion is that, while competition fosters criticality, cooperation hinders it and can lead to more ordered or more disordered consensual outcomes. (paper: classical statistical mechanics, equilibrium and non-equilibrium)

  11. Criticality safety validation: Simple geometry, single unit {sup 233}U systems

    Energy Technology Data Exchange (ETDEWEB)

    Putman, V.L.

    1997-06-01

    Typically used LMITCO criticality safety computational methods are evaluated for suitability when applied to INEEL {sup 233}U systems which reasonably can be modeled as simple-geometry, single-unit systems. Sixty-seven critical experiments of uranium highly enriched in {sup 233}U, including 57 aqueous solution, thermal-energy systems and 10 metal, fast-energy systems, were modeled. These experiments include 41 cylindrical and 26 spherical cores, and 41 reflected and 26 unreflected systems. No experiments were found for intermediate-neutron-energy ranges, or with interstitial non-hydrogenous materials typical of waste systems, mixed {sup 233}U and plutonium, or reflectors such as steel, lead, or concrete. No simple geometry experiments were found with cubic or annular cores, or approximating infinite sea systems. Calculations were performed with various tools and methodologies. Nine cross-section libraries, based on ENDF/B-IV, -V, or -VI.2, or on Hansen-Roach source data, were used with cross-section processing methods of MCNP or SCALE. The k{sub eff} calculations were performed with neutral-particle transport and Monte Carlo methods of criticality codes DANT, MCNP 4A, and KENO Va.

  12. Ethics Leadership in Research, Healthcare and Organizational Systems: Commentary and Critical Reflections

    Science.gov (United States)

    Gabriele, Edward F.

    2011-01-01

    In the last decades there has arisen a greater awareness of the ever present need for critical academic reflection on the nature of ethics leadership and committees in research, healthcare, and organizational systems. Yet what is meant by ethics itself? How is ethics understood as a historical phenomenon? What challenges must ethics leaders face…

  13. Teaching the Banking System According to Critical Education. A Study of a Schoolbook on Economics

    Science.gov (United States)

    Vaina, Maria; Katidioti, Evaggelia; Ktitikos, Antonis

    2013-01-01

    The main objective of the current paper is to establish the deficiencies of teaching Economics in the Greek educational system. It also proposes critical education as a way of partially overcoming these issues and the way it can contribute to the protection of the everyday man and woman against the rising and current existential threats of the…

  14. Self-organized criticality in a sheared granular stick-slip system

    International Nuclear Information System (INIS)

    Dalton, Fergal; Corcoran, David

    2001-01-01

    We present an analysis of results obtained from a mechanical apparatus consisting of an annular plate shearing over a granular bed. The size, energy dissipation, and duration of slips in the system exhibit power-law distributions and a 1/f 2 power spectrum, in accordance with self-organized criticality. We draw similarities with earthquakes

  15. Preface of Special issue on Automated Verification of Critical Systems (AVoCS'14)

    NARCIS (Netherlands)

    Huisman, Marieke; van de Pol, Jaco

    2016-01-01

    AVoCS 2014, the 14th International Conference on Automated Verification of Critical Systems has been hosted by the University of Twente, and has taken place in Enschede, Netherlands, on 24–26 September, 2014. The aim of the AVoCS series is to contribute to the interaction and exchange of ideas among

  16. Hispanic American Degree Attainment and the Effects of Critical Events and Support Systems

    Science.gov (United States)

    Hernandez, Eduardo

    2012-01-01

    The purpose of this study is to identify the critical events and support systems that have contributed to the attainment of an academic doctorate by Hispanics and to discern the similarities that existed in their parental educational level, socioeconomic status, and cultural background. The study will furthermore seek to identify major obstacles…

  17. Critical success factors for implementing supply chain information systems : insights from the pork industry

    NARCIS (Netherlands)

    Denolf, J.M.

    2014-01-01

    Critical success factors for implementing supply chain information systems – Janne M. Denolf

    Due to intensified competition, companies realize that they should closely collaborate with their supply-chain partners to further cut costs and stay competitive. To do so,

  18. Towards a framework of critical success factors for implementing supply-chain information systems

    NARCIS (Netherlands)

    Denolf, J.M.; Wognum, P.M.; Trienekens, J.H.; Vorst, van der J.G.A.J.; Omta, S.W.F.

    2015-01-01

    Supply chain information systems (SCISs) have emerged as the core of successful management in supply chains. However, the difficulties of SCIS implementations have been widely cited in the literature. Research on the critical success factors (CSFs) for SCIS implementation is rather scarce and

  19. SLSF loop handling system. Volume III. AISC code evaluations and analysis of critical attachments

    International Nuclear Information System (INIS)

    Ahmed, H.; Cowie, A.; Malek, R.A.; Rafer, A.; Ma, D.; Tebo, F.

    1978-10-01

    SLSF loop handling system was analyzed for deadweight and postulated dynamic loading conditions using a linear elastic static equivalent method of stress analysis. Stress computations of Cradle and critical attachments per AISC Code guidelines are presented. HFEF is credited with in-depth review of initial phase of work

  20. A Critical Review of Instructional Design Process of Distance Learning System

    Science.gov (United States)

    Chaudry, Muhammad Ajmal; ur-Rahman, Fazal

    2010-01-01

    Instructional design refers to planning, development, delivery and evaluation of instructional system. It is an applied field of study aiming at the application of descriptive research outcomes in regular instructional settings. The present study was designed to critically review the process of instructional design at Allama Iqbal Open University…

  1. Degree of Schedulability of Mixed-Criticality Real-time Systems with Probabilistic Sporadic Tasks

    DEFF Research Database (Denmark)

    Boudjadar, Jalil; David, Alexandre; Kim, Jin Hyun

    2014-01-01

    We present the concept of degree of schedulability for mixed-criticality scheduling systems. This concept is given in terms of the two factors 1) Percentage of Missed Deadlines (PoMD), and 2) Degradation of the Quality of Service (DoQoS). The novel aspect is that we consider task arrival patterns...

  2. Unleashing the Effectiveness of Process-oriented Information Systems: Problem Analysis, Critical Success Factors, Implications

    NARCIS (Netherlands)

    Mutschler, B.B.; Reichert, M.U.; Bumiller, J.

    2008-01-01

    Process-oriented information systems (IS) aim at the computerized support of business processes. So far, contemporary IS have often fail to meet this goal. To better understand this drawback, to systematically identify its rationales, and to derive critical success factors for business process

  3. A Study on Critical Thinking Assessment System of College English Writing

    Science.gov (United States)

    Dong, Tian; Yue, Lu

    2015-01-01

    This research attempts to discuss the validity of introducing the evaluation of students' critical thinking skills (CTS) into the assessment system of college English writing through an empirical study. In this paper, 30 College English Test Band 4 (CET-4) writing samples were collected and analyzed. Students' CTS and the final scores of collected…

  4. Expressing best practices in (risk) analysis and testing of safety-critical systems using patterns

    DEFF Research Database (Denmark)

    Herzner, Wolfgang; Sieverding, Sven; Kacimi, Omar

    2014-01-01

    The continuing pervasion of our society with safety-critical cyber-physical systems not only demands for adequate (risk) analysis, testing and verification techniques, it also generates growing experience on their use, which can be considered as important as the tools themselves for their efficient...

  5. Singular elliptic systems involving concave terms and critical Caffarelli-Kohn-Nirenberg exponents

    Directory of Open Access Journals (Sweden)

    Mohammed E. O. El Mokhtar

    2012-03-01

    Full Text Available In this article, we establish the existence of at least four solutions to a singular system with a concave term, a critical Caffarelli-Kohn-Nirenberg exponent, and sign-changing weight functions. Our main tools are the Nehari manifold and the mountain pass theorem.

  6. Student Satisfaction with Learning Management Systems: A Lens of Critical Success Factors

    Science.gov (United States)

    Naveh, Gali; Tubin, Dorit; Pliskin, Nava

    2012-01-01

    Institutions of higher education have invested heavily in learning management systems (LMS) for creating course websites. Yet, how to assess LMS effectiveness is not fully agreed upon. Based on institutional theory, this article considers student satisfaction as indicative of LMS success and proposes a lens of critical success factors (CSF) as a…

  7. Applicability of object-oriented design methods and C++ to safety-critical systems

    International Nuclear Information System (INIS)

    Cuthill, B.B.

    1994-01-01

    This paper reports on a study identifying risks and benefits of using a software development methodology containing object-oriented design (OOD) techniques and using C++ as a programming language relative to selected features of safety-critical systems development. These features are modularity, functional diversity, removing ambiguous code, traceability, and real-time performance

  8. Critical Incident Stress Management (CISM) in complex systems: cultural adaptation and safety impacts in healthcare.

    Science.gov (United States)

    Müller-Leonhardt, Alice; Mitchell, Shannon G; Vogt, Joachim; Schürmann, Tim

    2014-07-01

    In complex systems, such as hospitals or air traffic control operations, critical incidents (CIs) are unavoidable. These incidents can not only become critical for victims but also for professionals working at the "sharp end" who may have to deal with critical incident stress (CIS) reactions that may be severe and impede emotional, physical, cognitive and social functioning. These CIS reactions may occur not only under exceptional conditions but also during every-day work and become an important safety issue. In contrast to air traffic management (ATM) operations in Europe, which have readily adopted critical incident stress management (CISM), most hospitals have not yet implemented comprehensive peer support programs. This survey was conducted in 2010 at the only European general hospital setting which implemented CISM program since 2004. The aim of the article is to describe possible contribution of CISM in hospital settings framed from the perspective of organizational safety and individual health for healthcare professionals. Findings affirm that daily work related incidents also can become critical for healthcare professionals. Program efficiency appears to be influenced by the professional culture, as well as organizational structure and policies. Overall, findings demonstrate that the adaptation of the CISM program in general hospitals takes time but, once established, it may serve as a mechanism for changing professional culture, thereby permitting the framing of even small incidents or near misses as an opportunity to provide valuable feedback to the system. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Random-fractal Ansatz for the configurations of two-dimensional critical systems.

    Science.gov (United States)

    Lee, Ching Hua; Ozaki, Dai; Matsueda, Hiroaki

    2016-12-01

    Critical systems have always intrigued physicists and precipitated the development of new techniques. Recently, there has been renewed interest in the information contained in the configurations of classical critical systems, whose computation do not require full knowledge of the wave function. Inspired by holographic duality, we investigated the entanglement properties of the classical configurations (snapshots) of the Potts model by introducing an Ansatz ensemble of random fractal images. By virtue of the central limit theorem, our Ansatz accurately reproduces the entanglement spectra of actual Potts snapshots without any fine tuning of parameters or artificial restrictions on ensemble choice. It provides a microscopic interpretation of the results of previous studies, which established a relation between the scaling behavior of snapshot entropy and the critical exponent. More importantly, it elucidates the role of ensemble disorder in restoring conformal invariance, an aspect previously ignored. Away from criticality, the breakdown of scale invariance leads to a renormalization of the parameter Σ in the random fractal Ansatz, whose variation can be used as an alternative determination of the critical exponent. We conclude by providing a recipe for the explicit construction of fractal unit cells consistent with a given scaling exponent.

  10. Critical opalescence and the true dielectric state in a Coulomb system

    Science.gov (United States)

    Bobrov, V. B.; Trigger, S. A.

    2015-04-01

    To study the critical opalescence effect in a two-component Coulomb system consisting of single-type electrons and nuclei, we consider the limit relations for static structure factors and analyze the singularities of the dielectric permittivity. We show that the critical opalescence effect can be observed not only at the critical point corresponding to the gas-liquid phase transition but also near the true dielectric state with zero static conductivity. With the available experimental data taken into account, we assume that the true dielectric state is the limit state of the liquid-liquid phase transition accompanied by sharp variations in the electrical conduction of the substances. We find that if the thermodynamic parameters correspond to the true dielectric state, then the critical opalescence effect can arise in the case where the squared fluctuation in the total number of electrons and nuclei in a two-component Coulomb system becomes infinite, as this occurs at the critical point corresponding to the gas-liquid phase transition.

  11. Microgrids for Service Restoration to Critical Load in a Resilient Distribution System

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yin; Liu, Chen-Ching; Schneider, Kevin P.; Tuffner, Francis K.; Ton, Dan T.

    2018-01-01

    icrogrids can act as emergency sources to serve critical loads when utility power is unavailable. This paper proposes a resiliency-based methodology that uses microgrids to restore critical loads on distribution feeders after a major disaster. Due to limited capacity of distributed generators (DGs) within microgrids, dynamic performance of the DGs during the restoration process becomes essential. In this paper, the stability of microgrids, limits on frequency deviation, and limits on transient voltage and current of DGs are incorporated as constraints of the critical load restoration problem. The limits on the amount of generation resources within microgrids are also considered. By introducing the concepts of restoration tree and load group, restoration of critical loads is transformed into a maximum coverage problem, which is a linear integer program (LIP). The restoration paths and actions are determined for critical loads by solving the LIP. A 4-feeder, 1069-bus unbalanced test system with four microgrids is utilized to demonstrate the effectiveness of the proposed method. The method is applied to the distribution system in Pullman, WA, resulting in a strategy that uses generators on the Washington State University campus to restore service to the Hospital and City Hall in Pullman.

  12. Phase equilibria and critical phenomena in the cesium nitrate-water-diethylamine ternary system

    International Nuclear Information System (INIS)

    Il'in, K.K.; Kurskij, V.F.; Cherkasov, D.G.

    2008-01-01

    Phase equilibria and critical events in ternary cesium nitrate-water-diethylamine system, where border binary liquid system is characterized by aliquation with lower critical temperature of solution (LCTS), have been investigated by visual-polythermal method in the 60-150 Deg C range. Interaction of cesium nitrate in the water-diethylamine system leads to lowering of its LCTS from 146.1 to 69.3 Deg C and decrease of mutual solubility. Distribution ratios of diethylamine between water and organic phases of monotectic equilibrium are calculated at different temperatures. Diethylamine salting out from aqueous solutions by cesium nitrates becomes stronger with rising temperature. Plotted isotherms of phase confirms generalized scheme of topological transformations of ternary systems phase diagrams: salt-binary solvent with salting out

  13. Optimal system size for complex dynamics in random neural networks near criticality

    Energy Technology Data Exchange (ETDEWEB)

    Wainrib, Gilles, E-mail: wainrib@math.univ-paris13.fr [Laboratoire Analyse Géométrie et Applications, Université Paris XIII, Villetaneuse (France); García del Molino, Luis Carlos, E-mail: garciadelmolino@ijm.univ-paris-diderot.fr [Institute Jacques Monod, Université Paris VII, Paris (France)

    2013-12-15

    In this article, we consider a model of dynamical agents coupled through a random connectivity matrix, as introduced by Sompolinsky et al. [Phys. Rev. Lett. 61(3), 259–262 (1988)] in the context of random neural networks. When system size is infinite, it is known that increasing the disorder parameter induces a phase transition leading to chaotic dynamics. We observe and investigate here a novel phenomenon in the sub-critical regime for finite size systems: the probability of observing complex dynamics is maximal for an intermediate system size when the disorder is close enough to criticality. We give a more general explanation of this type of system size resonance in the framework of extreme values theory for eigenvalues of random matrices.

  14. Overview of Risk Mitigation for Safety-Critical Computer-Based Systems

    Science.gov (United States)

    Torres-Pomales, Wilfredo

    2015-01-01

    This report presents a high-level overview of a general strategy to mitigate the risks from threats to safety-critical computer-based systems. In this context, a safety threat is a process or phenomenon that can cause operational safety hazards in the form of computational system failures. This report is intended to provide insight into the safety-risk mitigation problem and the characteristics of potential solutions. The limitations of the general risk mitigation strategy are discussed and some options to overcome these limitations are provided. This work is part of an ongoing effort to enable well-founded assurance of safety-related properties of complex safety-critical computer-based aircraft systems by developing an effective capability to model and reason about the safety implications of system requirements and design.

  15. Optimal system size for complex dynamics in random neural networks near criticality

    International Nuclear Information System (INIS)

    Wainrib, Gilles; García del Molino, Luis Carlos

    2013-01-01

    In this article, we consider a model of dynamical agents coupled through a random connectivity matrix, as introduced by Sompolinsky et al. [Phys. Rev. Lett. 61(3), 259–262 (1988)] in the context of random neural networks. When system size is infinite, it is known that increasing the disorder parameter induces a phase transition leading to chaotic dynamics. We observe and investigate here a novel phenomenon in the sub-critical regime for finite size systems: the probability of observing complex dynamics is maximal for an intermediate system size when the disorder is close enough to criticality. We give a more general explanation of this type of system size resonance in the framework of extreme values theory for eigenvalues of random matrices

  16. CriticalEd

    DEFF Research Database (Denmark)

    Kjellberg, Caspar Mølholt; Meredith, David

    2014-01-01

    . Since the comments are not input sequentially, with regard to position, but in arbitrary order, this list must be sorted by copy/pasting the rows into place—an error-prone and time-consuming process. Scholars who produce critical editions typically use off-the-shelf music notation software......The best text method is commonly applied among music scholars engaged in producing critical editions. In this method, a comment list is compiled, consisting of variant readings and editorial emendations. This list is maintained by inserting the comments into a document as the changes are made......, consisting of a Sibelius plug-in, a cross-platform application, called CriticalEd, and a REST-based solution, which handles data storage/retrieval. A prototype has been tested at the Danish Centre for Music Publication, and the results suggest that the system could greatly improve the efficiency...

  17. Decomobil, Deliverable 3.6, Human Centred Design for Safety Critical Transport Systems

    OpenAIRE

    PAUZIE, Annie; MENDOZA, Lucile; SIMOES, Anabela; BELLET, Thierry; MOREAU, Fabien

    2014-01-01

    The scientific seminar on 'Human Centred Design for Safety Critical Transport Systems' organized in the framework of DECOMOBIL has been held the 8th of September 2014 in Lisbon, Portugal, hosted by ADI/ISG. The aims of the event were to present the scientific problematic related to the safety of the complex transport systems and the increasing importance of human-­centred design, with a specific focus on Resilience Engineering concept, a new approach to safety management in highly complex sys...

  18. The New Russian Budget System; A Critical Assessment and Future Reform Agenda

    OpenAIRE

    Jack Diamond

    2002-01-01

    This paper documents the main elements of the new budget system established in the Russian Federation through its revised budget system law, or the Budget Code, of 2000. It critically examines the budget preparation, budget approval, and budget execution processes, as well as the financial management and planning procedures that underlie the Budget Code. Based on this analysis, recent developments are discussed and a future reform agenda is indicated.

  19. A Methodological Framework for Software Safety in Safety Critical Computer Systems

    OpenAIRE

    P. V. Srinivas Acharyulu; P. Seetharamaiah

    2012-01-01

    Software safety must deal with the principles of safety management, safety engineering and software engineering for developing safety-critical computer systems, with the target of making the system safe, risk-free and fail-safe in addition to provide a clarified differentaition for assessing and evaluating the risk, with the principles of software risk management. Problem statement: Prevailing software quality models, standards were not subsisting in adequately addressing the software safety ...

  20. The Patient-Centered Medical Home Neighbor: A Critical Concept for a Redesigned Healthcare Delivery System

    Science.gov (United States)

    2011-01-25

    Sharing Knowledge: Achieving Breakthrough Performance 2010 Military Health System Conference The Patient -Centered Medical Home Neighbor: A Critical...DATE 25 JAN 2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE The Patient -Centered Medical Home Neighbor: A...Conference What is the Patient -Centered Medical Home?  …a vision of health care as it should be  …a framework for organizing systems of care at both the

  1. An overview of the V&V of Flight-Critical Systems effort at NASA

    Science.gov (United States)

    Brat, Guillaume P.

    2011-01-01

    As the US is getting ready for the Next Generation (NextGen) of Air Traffic System, there is a growing concern that the current techniques for verification and validation will not be adequate for the changes to come. The JPDO (in charge of implementing NextGen) has given NASA a mandate to address the problem and it resulted in the formulation of the V&V of Flight-Critical Systems effort. This research effort is divided into four themes: argument-based safety assurance, distributed systems, authority and autonomy, and, software intensive systems. This paper presents an overview of the technologies that will address the problem.

  2. ASIC-based design of NMR system health monitor for mission/safety?critical applications

    OpenAIRE

    Balasubramanian, P.

    2016-01-01

    N-modular redundancy (NMR) is a generic fault tolerance scheme that is widely used in safety?critical circuit/system designs to guarantee the correct operation with enhanced reliability. In passive NMR, at least a majority (N?+?1)/2 out of N function modules is expected to operate correctly at any time, where N is odd. Apart from a conventional realization of the NMR system, it would be useful to provide a concurrent indication of the system?s health so that an appropriate remedial action may...

  3. SACS2: Dynamic and Formal Safety Analysis Method for Complex Safety Critical System

    International Nuclear Information System (INIS)

    Koh, Kwang Yong; Seong, Poong Hyun

    2009-01-01

    Fault tree analysis (FTA) is one of the most widely used safety analysis technique in the development of safety critical systems. However, over the years, several drawbacks of the conventional FTA have become apparent. One major drawback is that conventional FTA uses only static gates and hence can not capture dynamic behaviors of the complex system precisely. Although several attempts such as dynamic fault tree (DFT), PANDORA, formal fault tree (FFT) and so on, have been made to overcome this problem, they can not still do absolute or actual time modeling because they adapt relative time concept and can capture only sequential behaviors of the system. Second drawback of conventional FTA is its lack of rigorous semantics. Because it is informal in nature, safety analysis results heavily depend on an analyst's ability and are error-prone. Finally reasoning process which is to check whether basic events really cause top events is done manually and hence very labor-intensive and timeconsuming for the complex systems. In this paper, we propose a new safety analysis method for complex safety critical system in qualitative manner. We introduce several temporal gates based on timed computational tree logic (TCTL) which can represent quantitative notion of time. Then, we translate the information of the fault trees into UPPAAL query language and the reasoning process is automatically done by UPPAAL which is the model checker for time critical system

  4. The Brazil socio-educational care system: contribution for an analysis critical of the policy

    Directory of Open Access Journals (Sweden)

    Candida de Souza

    2017-04-01

    Full Text Available The Socio-Educational system is the policy of care for juvenile delinquents in Brazil. This policy is challenged to differentiate the prison system, because it’s pedagogic and sanctionatory in the same time. In this paper we propose to make a critical analysis of the implementation of the policy of children and adolescents in Brazil, especially the socio-educational system, under a critical view, with foundation in dialectical historical materialism. So we present the historical evolution of the attention to the rights of children and adolescents in Brazil and aim the limitations and possibilities of this policy today, in addition to the current operation of this policy, followed by an analysis based on critical criminology. Finally, we indicate that the juvenile justice system, the socio-educational system and all social practices relating to offenses should be seen as part of an historical and social process that has as its central point the materiality of social relations, the relationship between society, market and State and the consequent contradictions that are placed there. As the socio-educational project is linked to a contemporary neoliberal state, he does not escape the pressure of capitalism. That is, you can not understand the socio-educational institutions and logic that supports policies so displaced from this broader socio-political system that perpetuates unevenly and exclusive.

  5. A safety-critical decision support system evaluation using situation awareness and workload measures

    International Nuclear Information System (INIS)

    Naderpour, Mohsen; Lu, Jie; Zhang, Guangquan

    2016-01-01

    To ensure the safety of operations in safety-critical systems, it is necessary to maintain operators' situation awareness (SA) at a high level. A situation awareness support system (SASS) has therefore been developed to handle uncertain situations [1]. This paper aims to systematically evaluate the enhancement of SA in SASS by applying a multi-perspective approach. The approach consists of two SA metrics, SAGAT and SART, and one workload metric, NASA-TLX. The first two metrics are used for the direct objective and subjective measurement of SA, while the third is used to estimate operator workload. The approach is applied in a safety-critical environment called residue treater, located at a chemical plant in which a poor human-system interface reduced the operator's SA and caused one of the worst accidents in US history. A counterbalanced within-subjects experiment is performed using a virtual environment interface with and without the support of SASS. The results indicate that SASS improves operators' SA, and specifically has benefits for SA levels 2 and 3. In addition, it is concluded that SASS reduces operator workload, although further investigations in different environments with a larger number of participants have been suggested. - Highlights: • The suitability of a cognitive decision support system is investigated. • An evaluation approach considering situation awareness and workload measures is proposed. • A computerized system based on the proposed approach is implemented. • The implemented system is used in a safety-critical environment.

  6. Determination of safety specifications as for criticality in pipelines systems with intersection

    International Nuclear Information System (INIS)

    Santos, R. dos; Vellozo, S.O.

    1982-01-01

    By the Monte Carlo method, criticality calculations were done for pipelines with several types of reflexion and configurations, filled with solution of plutonium nitrate, with 100 per cent of weight of Pu-239 isotope, in water. From the more simple pipeline intersection condition, type T, an intersection type cross and Double cross are studied. A second central column is aded. The intersections are studied in the minimal, nominal and maximal reflexion condition. Critical safety values are presented for some systems. (E.G.) [pt

  7. Benchmarks of subcriticality in accelerator-driven system at Kyoto University Critical Assembly

    Directory of Open Access Journals (Sweden)

    Cheol Ho Pyeon

    2017-09-01

    Full Text Available Basic research on the accelerator-driven system is conducted by combining 235U-fueled and 232Th-loaded cores in the Kyoto University Critical Assembly with the pulsed neutron generator (14 MeV neutrons and the proton beam accelerator (100 MeV protons with a heavy metal target. The results of experimental subcriticality are presented with a wide range of subcriticality level between near critical and 10,000 pcm, as obtained by the pulsed neutron source method, the Feynman-α method, and the neutron source multiplication method.

  8. System Guidelines for EMC Safety-Critical Circuits: Design, Selection, and Margin Demonstration

    Science.gov (United States)

    Lawton, R. M.

    1996-01-01

    Demonstration of safety margins for critical points (circuits) has traditionally been required since it first became a part of systems-level Electromagnetic Compatibility (EMC) requirements of MIL-E-6051C. The goal of this document is to present cost-effective guidelines for ensuring adequate Electromagnetic Effects (EME) safety margins on spacecraft critical circuits. It is for the use of NASA and other government agencies and their contractors to prevent loss of life, loss of spacecraft, or unacceptable degradation. This document provides practical definition and treatment guidance to contain costs within affordable limits.

  9. Emergence of criticality in the transportation passenger flow: scaling and renormalization in the Seoul bus system.

    Science.gov (United States)

    Goh, Segun; Lee, Keumsook; Choi, Moo Young; Fortin, Jean-Yves

    2014-01-01

    Social systems have recently attracted much attention, with attempts to understand social behavior with the aid of statistical mechanics applied to complex systems. Collective properties of such systems emerge from couplings between components, for example, individual persons, transportation nodes such as airports or subway stations, and administrative districts. Among various collective properties, criticality is known as a characteristic property of a complex system, which helps the systems to respond flexibly to external perturbations. This work considers the criticality of the urban transportation system entailed in the massive smart card data on the Seoul transportation network. Analyzing the passenger flow on the Seoul bus system during one week, we find explicit power-law correlations in the system, that is, power-law behavior of the strength correlation function of bus stops and verify scale invariance of the strength fluctuations. Such criticality is probed by means of the scaling and renormalization analysis of the modified gravity model applied to the system. Here a group of nearby (bare) bus stops are transformed into a (renormalized) "block stop" and the scaling relations of the network density turn out to be closely related to the fractal dimensions of the system, revealing the underlying structure. Specifically, the resulting renormalized values of the gravity exponent and of the Hill coefficient give a good description of the Seoul bus system: The former measures the characteristic dimensionality of the network whereas the latter reflects the coupling between distinct transportation modes. It is thus demonstrated that such ideas of physics as scaling and renormalization can be applied successfully to social phenomena exemplified by the passenger flow.

  10. Emergence of criticality in the transportation passenger flow: scaling and renormalization in the Seoul bus system.

    Directory of Open Access Journals (Sweden)

    Segun Goh

    Full Text Available Social systems have recently attracted much attention, with attempts to understand social behavior with the aid of statistical mechanics applied to complex systems. Collective properties of such systems emerge from couplings between components, for example, individual persons, transportation nodes such as airports or subway stations, and administrative districts. Among various collective properties, criticality is known as a characteristic property of a complex system, which helps the systems to respond flexibly to external perturbations. This work considers the criticality of the urban transportation system entailed in the massive smart card data on the Seoul transportation network. Analyzing the passenger flow on the Seoul bus system during one week, we find explicit power-law correlations in the system, that is, power-law behavior of the strength correlation function of bus stops and verify scale invariance of the strength fluctuations. Such criticality is probed by means of the scaling and renormalization analysis of the modified gravity model applied to the system. Here a group of nearby (bare bus stops are transformed into a (renormalized "block stop" and the scaling relations of the network density turn out to be closely related to the fractal dimensions of the system, revealing the underlying structure. Specifically, the resulting renormalized values of the gravity exponent and of the Hill coefficient give a good description of the Seoul bus system: The former measures the characteristic dimensionality of the network whereas the latter reflects the coupling between distinct transportation modes. It is thus demonstrated that such ideas of physics as scaling and renormalization can be applied successfully to social phenomena exemplified by the passenger flow.

  11. Validation of the Continuous-Energy Monte Carlo Criticality-Safety Analysis System MVP and JENDL-3.2 Using the Internationally Evaluated Criticality Benchmarks

    International Nuclear Information System (INIS)

    Mitake, Susumu

    2003-01-01

    Validation of the continuous-energy Monte Carlo criticality-safety analysis system, comprising the MVP code and neutron cross sections based on JENDL-3.2, was examined using benchmarks evaluated in the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments'. Eight experiments (116 configurations) for the plutonium solution and plutonium-uranium mixture systems performed at Valduc, Battelle Pacific Northwest Laboratories, and other facilities were selected and used in the studies. The averaged multiplication factors calculated with MVP and MCNP-4B using the same neutron cross-section libraries based on JENDL-3.2 were in good agreement. Based on methods provided in the Japanese nuclear criticality-safety handbook, the estimated criticality lower-limit multiplication factors to be used as a subcriticality criterion for the criticality-safety evaluation of nuclear facilities were obtained. The analysis proved the applicability of the MVP code to the criticality-safety analysis of nuclear fuel facilities, particularly to the analysis of systems fueled with plutonium and in homogeneous and thermal-energy conditions

  12. R and D study on on-line criticality surveillance system (IV)

    International Nuclear Information System (INIS)

    Yamada, Sumasu

    2000-02-01

    Developing an inexpensive on-line criticality surveillance system is required for ensuring the safety of nuclear fuel reprocessing plants. Based on the series of researches for five years, R and D study on On-line Criticality Surveillance system has been carried out since 1996. The concept of this Criticality Surveillance System is based on the Auto-Regressive Moving Average (ARMA) model identification algorithms to the time series of signal fluctuation of a neutron detector. We have proposed several new ideas of modification to the original design of the Criticality Surveillance System, and also reported some results of numerical analysis over the DCA experiments. In those days, DOS/V personal computers with Microsoft Windows have came into wide use instead of those based on the MS-DOS, which have been popular in Japan. NEC, a major maker of MS-DOS computers, stopped the production of MS-DOS computers and changed their management policy toward production of DOS/V personal computers. Our researches have been developed using MS-DOS computers. For the effective use of these important results, it became an urgent theme to transplant all programs developed on MS-DOS computers into computers with the OS, which is not easily affected by commercialism. Since the design concept should be based on high reliability, electromagnetic disturbance-free and high expandability, and also computers have achieved remarkably high performance as well as low price in these days, these computers should be used not only as a simple signal processing unit but also a totally integrated signal analyzing system along with conventional signal analyzing software in stead of IC chips with analyzing soft wares. This configuration enables us to easily introduce newly developed techniques and to provide supplement information. Then, this approach can enhance the reliability of the Criticality Surveillance System without addition of any special devices, and also provide the flexibility of the system

  13. Regulating Critical Period Plasticity: Insight from the Visual System to Fear Circuitry for Therapeutic Interventions

    Directory of Open Access Journals (Sweden)

    Elisa M. Nabel

    2013-11-01

    Full Text Available Early temporary windows of heightened brain plasticity called critical periods developmentally sculpt neural circuits and contribute to adult behavior. Regulatory mechanisms of visual cortex development –the preeminent model of experience-dependent critical period plasticity- actively limit adult plasticity and have proved fruitful therapeutic targets to reopen plasticity and rewire faulty visual system connections later in life. Interestingly, these molecular mechanisms have been implicated in the regulation of plasticity in other functions beyond vision. Applying mechanistic understandings of critical period plasticity in the visual cortex to fear circuitry may provide a conceptual framework for developing novel therapeutic tools to mitigate aberrant fear responses in post traumatic stress disorder. In this review, we turn to the model of experience-dependent visual plasticity to provide novel insights for the mechanisms regulating plasticity in the fear system. Fear circuitry, particularly fear memory erasure, also undergoes age-related changes in experience-dependent plasticity. We consider the contributions of molecular brakes that halt visual critical period plasticity to circuitry underlying fear memory erasure. A major molecular brake in the visual cortex, perineuronal net formation, recently has been identified in the development of fear systems that are resilient to fear memory erasure. The roles of other molecular brakes, myelin-related Nogo receptor signaling and Lynx family proteins– endogenous inhibitors for nicotinic acetylcholine receptor, are explored in the context of fear memory plasticity. Such fear plasticity regulators, including epigenetic effects, provide promising targets for therapeutic interventions.

  14. Minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, W.C.; Turner, J.C.

    1992-12-01

    A parametric calculational analysis has been performed in order to estimate the minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems. The analysis was performed using a version of the SCALE-4.0 code system and the 27-group ENDF/B-IV cross-section library. Water-moderated uranyl fluoride (UO{sub 2}F{sub 2} and H{sub 2}O) and hydrofluoric-acid-moderated uranium hexaflouride (UF{sub 6} and HF) systems were considered in the analysis over enrichments of 1.4 to 5 wt % {sup 235}U. Estimates of the minimum critical volume, minimum critical mass of uranium, and the minimum mass of moderator required for criticality are presented. There was significant disagreement between the values generated in this study when compared with a similar undocumented study performed in 1983 using ANISN and the Knight-modified Hansen-Roach cross sections. An investigation into the cause of the disagreement was made, and the results are presented.

  15. Minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, W.C.; Turner, J.C.

    1992-12-01

    A parametric calculational analysis has been performed in order to estimate the minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems. The analysis was performed using a version of the SCALE-4.0 code system and the 27-group ENDF/B-IV cross-section library. Water-moderated uranyl fluoride (UO[sub 2]F[sub 2] and H[sub 2]O) and hydrofluoric-acid-moderated uranium hexaflouride (UF[sub 6] and HF) systems were considered in the analysis over enrichments of 1.4 to 5 wt % [sup 235]U. Estimates of the minimum critical volume, minimum critical mass of uranium, and the minimum mass of moderator required for criticality are presented. There was significant disagreement between the values generated in this study when compared with a similar undocumented study performed in 1983 using ANISN and the Knight-modified Hansen-Roach cross sections. An investigation into the cause of the disagreement was made, and the results are presented.

  16. Validation of the Monte Carlo Criticality Program KENO V. a for highly-enriched uranium systems

    Energy Technology Data Exchange (ETDEWEB)

    Knight, J.R.

    1984-11-01

    A series of calculations based on critical experiments have been performed using the KENO V.a Monte Carlo Criticality Program for the purpose of validating KENO V.a for use in evaluating Y-12 Plant criticality problems. The experiments were reflected and unreflected systems of single units and arrays containing highly enriched uranium metal or uranium compounds. Various geometrical shapes were used in the experiments. The SCALE control module CSAS25 with the 27-group ENDF/B-4 cross-section library was used to perform the calculations. Some of the experiments were also calculated using the 16-group Hansen-Roach Library. Results are presented in a series of tables and discussed. Results show that the criteria established for the safe application of the KENO IV program may also be used for KENO V.a results.

  17. Critical behavior in reaction-diffusion systems exhibiting absorbing phase transition

    CERN Document Server

    Ódor, G

    2003-01-01

    Phase transitions of reaction-diffusion systems with site occupation restriction and with particle creation that requires n>1 parents and where explicit diffusion of single particles (A) exists are reviewed. Arguments based on mean-field approximation and simulations are given which support novel kind of non-equilibrium criticality. These are in contradiction with the implications of a suggested phenomenological, multiplicative noise Langevin equation approach and with some of recent numerical analysis. Simulation results for the one and two dimensional binary spreading 2A -> 4A, 4A -> 2A model display a new type of mean-field criticality characterized by alpha=1/3 and beta=1/2 critical exponents suggested in cond-mat/0210615.

  18. Attractive forces study in macromolecules and critical systems; Etude des forces attractives dans les macromolecules et les systemes critiques

    Energy Technology Data Exchange (ETDEWEB)

    Penninckx-Sans, A.

    1995-07-10

    The attractive forces effect is particularly interesting at the proximity of a critical point. In a liquid system, there are two kinds of attractive forces in presence : the forces bound to the solution volume and those generated by the presence of the solution surface or by a solution interface. In the first case, the attractive forces are the more important as the system is in a critical field. For this study, the selected example is a polymer solution in a two solvents mixture. A formulation in terms of way integrals as part of statistical physics has lead us to find again some known results on the polymer chain conformation in the presence of two solvents (collapse of the polymer on itself) far from the critical point and to extend these results to the critical field. In the case of attractive forces created by the surface in some critical systems (polymer of infinite size in solution and binary mixture near the de mixture point), the adsorption profile created by the attraction of one specie by the surface, follows a scale law. The optical methods usually used for the study of these systems do not give characteristic sign of concentration profile in power law. In the case where the interaction potential between radiation and matter is attractive, the reflectivity gives a separate mark of the existence of the scale law in the form of a resonance. After some theoretical forecasts, the author has used this method on the binary mixture methanol-cyclohexane in order to reveal experimentally a reflectivity pseudo-discontinuity and then the existence of the power law in the critical adsorption profile. (O.L.). 69 refs., 60 tabs.

  19. The impact of natural hazard on critical infrastructure systems: definition of an ontology

    Science.gov (United States)

    Dimauro, Carmelo; Bouchon, Sara; Frattini, Paolo; Giusto, Claudia

    2013-04-01

    According to the Council of the European Union Directive (2008), 'critical infrastructure' means an asset, system or part thereof which is essential for the maintenance of vital societal functions, health, safety, security, economic or social well-being of people, and the disruption or destruction of which would have a significant impact as a result of the failure to maintain those functions. Critical infrastructure networks are exposed to natural events, such as floods, storms, landslides, earthquakes, etc. Recent natural disasters show that socio-economic consequences can be very much aggravated by the impact on these infrastructures. Though, there is still a lack of a recognized approach or methodology to assess the vulnerability of critical infrastructure assets against natural threats. The difficulty to define such an approach is increased by the need to consider a very high number of natural events, which differ in nature, magnitude and probability, as well as the need to assess the vulnerability of a high variety of infrastructure assets (e.g. bridges, roads, tunnels, pipelines, etc.) To meet this challenge, the objective of the THREVI2 EU-CIPS project is to create a database linking the relationships between natural hazards and critical infrastructure assets. The query of the database will allow the end-users (critical infrastructure protection authorities and operators) to identify the relevant scenarios according to the own priorities and criteria. The database builds on an ontology optimized for the assessment of the impact of threats on critical infrastructures. The ontology aims at capturing the existing knowledge on natural hazards, critical infrastructures assets and their related vulnerabilities. Natural phenomena that can threaten critical infrastructures are classified as "events", and organized in a genetic-oriented hierarchy. The main attributes associated to each event are the probability, the magnitude and the "modus". The modus refers to the

  20. Critical transitions in chronic disease: transferring concepts from ecology to systems medicine.

    Science.gov (United States)

    Trefois, Christophe; Antony, Paul M A; Goncalves, Jorge; Skupin, Alexander; Balling, Rudi

    2015-08-01

    Ecosystems and biological systems are known to be inherently complex and to exhibit nonlinear dynamics. Diseases such as microbiome dysregulation or depression can be seen as complex systems as well and were shown to exhibit patterns of nonlinearity in their response to perturbations. These nonlinearities can be revealed by a sudden shift in system states, for instance from health to disease. The identification and characterization of early warning signals which could predict upcoming critical transitions is of primordial interest as prevention of disease onset is a major aim in health care. In this review, we focus on recent evidence for critical transitions in diseases and discuss the potential of such studies for therapeutic applications. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Regionalization in the SUS: implementation process, challenges and perspectives in the critical view of system managers.

    Science.gov (United States)

    Carvalho, Andre Luis Bonifácio de; Jesus, Washington Luiz Abreu de; Senra, Isabel Maria Vilas Boas

    2017-04-01

    This article examines the regionalization process in the Brazilian Health System, identifying frameworks and challenges of this process from critical dialogue on the subject, contextualized by the experience of the management system and in the light of an established theoretical debate in the last decade. We used the thematic content analysis of legal and documentary surveys of the regionalization process in SUS, collated by elements of the historical and political context in the period. As evidence, it appears that the regionalization process has been incremental decentralization/deconcentration of management and health actions and services. There are important challenges, particularly in relation to ensuring access and system governance structure, which contributes to critical thinking and construction of new perspectives by those who lead their implementation.

  2. Study on criticality safety evaluation of a system where flood will never occur

    International Nuclear Information System (INIS)

    Naito, Yoshitaka; Yamamoto, Toshihiro; Komuro, Yuichi; Itahara, Kuniyuki.

    1995-03-01

    Criticality safety evaluation for a single unit containing nuclear fuel has usually been performed on the assumption that there is a fully thick water reflector around the unit. For a system where flood will never occur, however, the thick reflector assumption is usually not applied recently. In such cases, a method is proposed, which models surrounding structural material and branch pipes as 2.5cm thick water reflector. This report shows that reactivity worth of structural material and branch pipes is, in many cases, less than that of 2.5cm thick water reflector. Further, another method is shown to evaluate criticality safety for a multiple unit system, using computed results with surrounding structural material and branch pipes neglected. And it is shown with many sample calculations that the method with 2.5cm thick water reflector in place of structural material and pipes gives safety side results to similar systems to real reprocessing plants. (author)

  3. Replacement of the criticality accident alarm system in the Tokai reprocessing plant

    International Nuclear Information System (INIS)

    Sanada, Yukihisa; Momose, Takumaro; Suzuki, Kei; Kawai, Keiichi

    2008-01-01

    A Criticality Accident Alarm System (CAAS) was installed as part of criticality safety management for use in reducing the radiation workers could be exposed to in the rare case of a criticality accident. The initial CAAS version was installed the Tokai Reprocessing Plant (TRP) in the 1980s. It includes units that can detect gamma-rays or neutron-rays released in criticality accidents (CADs), one of which consists of three plastic scintillation gamma detectors and three solid state neutron detectors with fissile material, and in being highly reliable utilizes the 2 out of 3 voting system. The purpose of this study is to give the design principles and procedures for determining the adequate relocation of the CADs within the TRP. The optimal places for the CADs to be relocated to were determined using a conservative evaluation method. Firstly, equipment needing to be monitored for criticality accidents was selected with consideration given to the risk of excessive exposure to workers. Secondly, the detection threshold of a minimum accident was set to be an increase in power of 10 15 fissions/s occurring within a rise-time of between 0.5 ms and 1 s. The sum of neutron and gamma doses of a minimum accident (10 15 fissions) was 0.3 Gy at an unshielded distance of 1 m. Finally, doses at where the CADs were installed were evaluated using parameters calculated with MCNP and ANISN. As a result, the alarm trip level of both the gamma detector and the neutron detector being set at 2.0 mGy/h enabled minimum criticality accidents to be conservatively detected. These results were then applied to the new CAD positions. (author)

  4. A semilinear parabolic–elliptic chemotaxis system with critical mass in any space dimension

    International Nuclear Information System (INIS)

    Montaru, Alexandre

    2013-01-01

    We study radial solutions in a ball of R N of a semilinear, parabolic–elliptic Patlak–Keller–Segel system with a nonlinear sensitivity involving a critical power. For N = 2, the latter reduces to the classical ‘linear’ model, well known for its critical mass 8π. We show that a critical mass phenomenon also occurs for N ⩾ 3, but with a strongly different qualitative behaviour. More precisely, if the total mass of cells is smaller or equal to the critical mass M-bar , then the cell density converges to a regular steady state that is supported strictly inside the ball as time goes to infinity. In the case of the critical mass, this result is nontrivial since there exists a continuum of stationary solutions and is moreover in sharp contrast with the case N = 2 where infinite-time blow-up occurs. If the total mass of cells is larger than M-bar , then all radial solutions blow up in finite time. This actually follows from the existence (unlike for N = 2) of a family of self-similar, blowing-up solutions that are supported strictly inside the ball. (paper)

  5. Physician satisfaction with a critical care clinical information system using a multimethod evaluation of usability.

    Science.gov (United States)

    Hudson, Darren; Kushniruk, Andre; Borycki, Elizabeth; Zuege, Danny J

    2018-04-01

    Physician satisfaction with electronic medical records has often been poor. Usability has frequently been identified as a source for decreased satisfaction. While surveys can identify many issues, and are logistically easier to administer, they may miss issues identified using other methods This study sought to understand the level of physician satisfaction and usability issues associated with a critical care clinical information system (eCritical Alberta) implemented throughout the province of Alberta, Canada. All critical care attending physicians using the system were invited to participate in an online survey. Questions included components of the User Acceptance of Information Technology and Usability Questionnaire as well as free text feedback on system components. Physicians were also invited to participate in a think aloud test using simulated scenarios. The transcribed think aloud text and questionnaire were subjected to textual analysis. 82% of all eligible physicians completed the on-line survey (n = 61). Eight physicians were invited and seven completed the think aloud test. Overall satisfaction with the system was moderate. Usability was identified as a significant factor contributing to satisfaction. The major usability factors identified were system response time and layout. The think aloud component identified additional factors beyond those identified in the on-line survey. This study found a modestly high level of physician satisfaction with a province-wide clinical critical care information system. Usability continues to be a significant factor in physician satisfaction. Using multiple methods of evaluation can capture the benefits of a large sample size and deeper understanding of the issues. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Development of the efficient emergency preparedness system for the nuclear critical infrastructure

    International Nuclear Information System (INIS)

    Kostadinov, V.; Marn, J.; Petelin, S.

    2007-01-01

    The evaluation of the critical nuclear infrastructure vulnerability to threats like human occurrences, terrorist attacks and natural disasters and the preparation of emergency response plans with the estimation of optimized costs are of the vital importance for the assurance of a safe nuclear facilities operation and the national security. In the past national emergency systems did not include vulnerability assessments of the critical nuclear infrastructure as the important part of the comprehensive preparedness framework. The fundamental aims of the efficient emergency preparedness and response system are to provide a sustained emergency readiness and to prevent an emergency situation and accidents. But when an event happens the mission is to mitigate consequences and to protect the people and environment against the nuclear and radiological damage. The efficient emergency response system, which would be activated in the case of the nuclear and/or radiological emergency and release of the radioactivity to the environment, is an important element of a comprehensive system of the nuclear and radiation safety. In the article the new methodology for the critical nuclear infrastructure vulnerability assessment as a missing part of an efficient emergency preparedness system is presented. It can help the overall national energy sectors to identify and better understand the terrorist threats and vulnerabilities of their critical infrastructure. The presented methodology could also facilitate national agencies to develop and implement a vulnerability awareness and education programs for their critical assets to enhance the security, reliability and safe operation of the whole energy infrastructure. The vulnerability assessment methodology will also assist nuclear power plants to develop, validate, and disseminate the assessment and survey of new efficient countermeasures. The significant benefits of the new vulnerability assessment research are to increase nuclear power

  7. Validation of the ABBN/CONSYST constants system. Part 1: Validation through the critical experiments on compact metallic cores

    International Nuclear Information System (INIS)

    Ivanova, T.T.; Manturov, G.N.; Nikolaev, M.N.; Rozhikhin, E.V.; Semenov, M.Yu.; Tsiboulia, A.M.

    1999-01-01

    Worldwide compilation of criticality safety benchmark experiments, evaluated due to an activity of the International Criticality Safety Benchmark Evaluation Project (ICSBEP), discovers new possibilities for validation of the ABBN-93.1 cross section library for criticality safety analysis. Results of calculations of small assemblies with metal-fuelled cores are presented in this paper. It is concluded that ABBN-93.1 predicts criticality of such systems with required accuracy

  8. A New Method to Detect and Correct the Critical Errors and Determine the Software-Reliability in Critical Software-System

    International Nuclear Information System (INIS)

    Krini, Ossmane; Börcsök, Josef

    2012-01-01

    In order to use electronic systems comprising of software and hardware components in safety related and high safety related applications, it is necessary to meet the Marginal risk numbers required by standards and legislative provisions. Existing processes and mathematical models are used to verify the risk numbers. On the hardware side, various accepted mathematical models, processes, and methods exist to provide the required proof. To this day, however, there are no closed models or mathematical procedures known that allow for a dependable prediction of software reliability. This work presents a method that makes a prognosis on the residual critical error number in software. Conventional models lack this ability and right now, there are no methods that forecast critical errors. The new method will show that an estimate of the residual error number of critical errors in software systems is possible by using a combination of prediction models, a ratio of critical errors, and the total error number. Subsequently, the critical expected value-function at any point in time can be derived from the new solution method, provided the detection rate has been calculated using an appropriate estimation method. Also, the presented method makes it possible to make an estimate on the critical failure rate. The approach is modelled on a real process and therefore describes two essential processes - detection and correction process.

  9. CETF Space Station payload pointing system design and analysis feasibility study. [Critical Evaluation Task Force

    Science.gov (United States)

    Smagala, Tom; Mcglew, Dave

    1988-01-01

    The expected pointing performance of an attached payload coupled to the Critical Evaluation Task Force Space Station via a payload pointing system (PPS) is determined. The PPS is a 3-axis gimbal which provides the capability for maintaining inertial pointing of a payload in the presence of disturbances associated with the Space Station environment. A system where the axes of rotation were offset from the payload center of mass (CM) by 10 in. in the Z axis was studied as well as a system having the payload CM offset by only 1 inch. There is a significant improvement in pointing performance when going from the 10 in. to the 1 in. gimbal offset.

  10. Predicting critical transitions in dynamical systems from time series using nonstationary probability density modeling.

    Science.gov (United States)

    Kwasniok, Frank

    2013-11-01

    A time series analysis method for predicting the probability density of a dynamical system is proposed. A nonstationary parametric model of the probability density is estimated from data within a maximum likelihood framework and then extrapolated to forecast the future probability density and explore the system for critical transitions or tipping points. A full systematic account of parameter uncertainty is taken. The technique is generic, independent of the underlying dynamics of the system. The method is verified on simulated data and then applied to prediction of Arctic sea-ice extent.

  11. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems.

    Science.gov (United States)

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-13

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha(-1) yr(-1), with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content.

  12. Review of design criteria for Criticality Accident Alarm System (CAAS) used in Fuel Reprocessing Facility

    International Nuclear Information System (INIS)

    Chandrasekaran, S.; Basu, Pew; Sivasubramaniyan, K.; Venkatraman, B.

    2016-01-01

    Though fuel cycle facilities handling fissile materials are designed with careful criticality safety analysis, the criticality accident cannot be ruled out completely. Criticality Accident Alarm System (CAAS) is being installed as part of criticality safety management in fuel cycle facilities. CAAS system being used in India, is ECIL make, ionization chamber based gamma detector, which houses three identical detectors and works on 2/3 logic. As per ISO 7753 and ANSI/ANS-8.3, the CAAS must be designed to be capable of detecting any minimum accident occurs which could be of concern. Based on this, alarm limit used in CAAS is: 4 R/h (fast transient excursion) and 3 mR in 0.5 sec (slow excursion). In case of reprocessing facilities wherein process tanks located in heavy shielding, identification of CAAS installation locations require detailed radiation transport calculations. A study has been taken to estimate the gamma dose rate from thick concrete hot cells in order to determine the locations of CAAS to meet the present design criteria of alarm limit

  13. Analytic evaluation of a new glucose meter system in 15 different critical care settings.

    Science.gov (United States)

    Mitsios, John V; Ashby, Lori A; Haverstick, Doris M; Bruns, David E; Scott, Mitchell G

    2013-09-01

    Maintaining appropriate glycemic control in critically ill patients reduces morbidity and mortality. The use of point-of-care (POC) glucose devices is necessary to obtain rapid results at the patient's bedside. However, the devices should be thoroughly tested in the intended population before implementation. The use of POC glucose meters in critically ill patients has been questioned both in the literature and by regulatory agencies. The aim of this study was to determine if the ACCU-CHEK® Inform II system (Roche Diagnostics) POC glucose meter demonstrated the desired accuracy and precision, as defined by Clinical and Laboratory Standards Institute guideline POCT12-A3, in a large number of critically ill patients from multiple intensive care settings at two academic medical centers. A total of 1200 whole blood meter results from 600 patients were compared with central laboratory plasma values. Whole blood aliquots from venous samples were used to obtain duplicate meter results with the remaining sample being processed to obtain plasma for central laboratory testing within 5 min of meter testing. A total of 1185 (98.8%) of the new meter's glucose values were within ± 12.5% (± 12 mg/dl for values ≥ 100 mg/dl) of the comparative laboratory glucose values, and 1198 (99.8%) were within ± 20% (± 20 mg/dl for values meter system appears to have sufficient analytic accuracy for use in critically ill patients. © 2013 Diabetes Technology Society.

  14. System implementation of hazard analysis and critical control points (HACCP) in a nitrogen production plant

    International Nuclear Information System (INIS)

    Barrantes Salazar, Alexandra

    2014-01-01

    System of hazard analysis and critical control points are deployed in a production plant of liquid nitrogen. The fact that the nitrogen has become a complement to food packaging to increase shelf life, or provide a surface that protect it from manipulation, has been the main objective. Analysis of critical control points for the nitrogen production plant has been the adapted methodology. The knowledge of both the standard and the production process, as well as the on site verification process, have been necessary. In addition, all materials and/or processing units that are found in contact with the raw material or the product under study were evaluated. Such a way that the intrinsic risks of each were detected, from the physical, chemical and biological points of view according to the origin or pollution source. For each found risk was evaluated the probability of occurrence according to the frequency and gravity of it, with these variables determined was achieved the definition of the type of risk detected. In the cases that was presented a greater risk or critical, these were subjected decision tree; with which is concluded the non determination of critical control points. However, for each one of them were established the maximum permitted limits. To generate each of the results it has literature or scientific reference of reliable provenance, where is indicated properly the support of the evaluated matter. In a general way, the material matrix and the process matrix are found without critical control points; so that the project is concluded in the analysis, and it has to generate without the monitoring system and verification. To increase this project is suggested in order to cover the packaging system of gaseous nitrogen, due to it was delimited to liquid nitrogen. Furthermore, the liquid nitrogen is a 100% automated and closed process so the introduction of contaminants is very reduced, unlike the gaseous nitrogen process. (author) [es

  15. System design and analysis of the trans-critical carbon-dioxide automotive air-conditioning system.

    Science.gov (United States)

    Mu, Jing-Yang; Chen, Jiang-Ping; Chen, Zhi-Jiu

    2003-01-01

    As an environmentally harmless and feasible alternate refrigerant, CO2 has attracted worldwide attention, especially in the area of automobile air-conditioning (AAC). The thermal property of CO2 and its trans-critical refrigeration cycle is very different from that of the traditional CFC or HCFC system. The detailed process of CO2 system thermal cycle design and optimization is described in this paper. System prototype and performance test bench were developed to analyze the performance of the CO2 AAC system.

  16. Audit of radiology communication systems for critical, urgent, and unexpected significant findings.

    Science.gov (United States)

    Duncan, K A; Drinkwater, K J; Dugar, N; Howlett, D C

    2016-03-01

    To determine the compliance of UK radiology departments and trusts/healthcare organisations with National Patient Safety Agency and Royal College of Radiologist's published guidance on the communication of critical, urgent, and unexpected significant radiological findings. A questionnaire was sent to all UK radiology department audit leads asking for details of their current departmental policy regarding the issuing of alerts; use of automated electronic alert systems; methods of notification of clinicians of critical, urgent, and unexpected significant radiological findings; monitoring of results receipt; and examples of the more common types of serious pathologies for which alerts were issued. One hundred and fifty-four of 229 departments (67%) responded. Eighty-eight percent indicated that they had a policy in place for the communication of critical, urgent, and unexpected significant radiological findings. Only 34% had an automated electronic alert system in place and only 17% had a facility for service-wide electronic tracking of radiology reports. In only 11 departments with an electronic acknowledgement system was someone regularly monitoring the read rate. There is wide variation in practice across the UK with regard to the communication and monitoring of reports with many departments/trusts not fully compliant with published UK guidance. Despite the widespread use of electronic systems, only a minority of departments/trusts have and use electronic tracking to ensure reports have been read and acted upon. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  17. Criticality safety of pipe systems which contain solutions of fissile materials

    International Nuclear Information System (INIS)

    Santos, R. dos.

    1982-03-01

    Criticality calculations for geometric configurations here studied make use of the neutron transport equation in its multigroup formulation, which is solved by the Monte Carlos statistical-probabilistic method. The computational code KENO IV, which use the Monte Carlo method, was utilized in all criticality calculations. All calculations were restricted to plutonium nitrate solutions, 100w% concentration of Pu-239, in water. Calculations were performed to obtain critical dimensions (radius) of a bare infinite cylinder and the effect produced by the addition of a 0.32 cm stainless steel cladding analyzed. Then, The most simple pipe intersection system is examined: the addition, of another cylinder to the one studied in the preceding case, constituting the type 'T' intersection. Further addition of a second cylinder, to the T-Type system is investigated; this is the cross-intersection type. Next, the effect produced by the introduction of a second central column to type 'T' system is analyzed. The effect of the introduction of several arms in the same quadrant is also studied. Infinite cylinders and cross-intersection type systems are analyzed in their nominal and maximum reflection conditions. (E.G.) [pt

  18. Modernization of control system of the beam critical parameters at a lu-10 industrial electron accelerator

    International Nuclear Information System (INIS)

    Pomatsalyuk, R.I.; Uvarov, V.L.; Shevchenko, V.A.; Shlyakhov, I.N.

    2017-01-01

    Continuous control and monitoring of critical parameters of radiation processing of products is one of the requirements of the international standard ISO 11137. The current system to monitoring the parameters of radiation treatment of products at the LU-10 accelerator is being in operation for more than 15 years. The life-time of the mayor part of measuring modules is over, and those modules are no longer produced. Modernization of monitoring system with the use of the multi-functional USB modules, single-board mini-computers and EPICS control system (Experimental Physics and Industrial Control System) is considered. The architecture and software for a new monitoring system have been developed. Debugging and operation of the system in a test mode is performed

  19. ASIC-based design of NMR system health monitor for mission/safety-critical applications.

    Science.gov (United States)

    Balasubramanian, P

    2016-01-01

    N-modular redundancy (NMR) is a generic fault tolerance scheme that is widely used in safety-critical circuit/system designs to guarantee the correct operation with enhanced reliability. In passive NMR, at least a majority (N + 1)/2 out of N function modules is expected to operate correctly at any time, where N is odd. Apart from a conventional realization of the NMR system, it would be useful to provide a concurrent indication of the system's health so that an appropriate remedial action may be initiated depending upon an application's safety criticality. In this context, this article presents the novel design of a generic NMR system health monitor which features: (i) early fault warning logic, that is activated upon the production of a conflicting result by even one output of any arbitrary function module, and (ii) error signalling logic, which signals an error when the number of faulty function modules unfortunately attains a majority and the system outputs may no more be reliable. Two sample implementations of NMR systems viz. triple modular redundancy and quintuple modular redundancy with the proposed system health monitoring are presented in this work, with a 4-bit ALU used for the function modules. The simulations are performed using a 32/28 nm CMOS process technology.

  20. Critical success factors in implementing an e-rostering system in a healthcare organisation.

    Science.gov (United States)

    Soomro, Zahoor A; Ahmed, Javed; Muhammad, Raza; Hayes, Dawn; Shah, Mahmood H

    2017-01-01

    Effective and efficient staff scheduling has always been a challenging issue, especially in health service organisations. Both the extremes of staff shortage and overage have an adverse impact on the performance of healthcare organisations. In this case, an electronic and systematic staff scheduling (e-rostering) system is the often seen as the best solution. Unless an organisation has an effective implementation of such a system, possible cost savings, efficiency, and benefits could be minimal. This study is aimed to research key success factors for the successful effective implementation of an electronic rostering system, especially at healthcare organisations. A case study research method was used to evaluate critical success factors for effectively implementing an e-rostering system. The data were collected through interviews and observations. The findings indicate that technical support, an effective policy, leadership, clear goals and objectives, gradual change, evidence of the advantages of the new system, senior management support, and effective communication are the critical success factors in implementing an e-rostering system in healthcare organisations. Prior to this study, no such factors were grounded in the current context, so this research would help in bridging the gap towards effective implementation of an e-rostering system in the healthcare sector. This research also suggests future studies in different cultures and contexts.