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Sample records for safety margins due

  1. Pickering seismic safety margin

    International Nuclear Information System (INIS)

    Ghobarah, A.; Heidebrecht, A.C.; Tso, W.K.

    1992-06-01

    A study was conducted to recommend a methodology for the seismic safety margin review of existing Canadian CANDU nuclear generating stations such as Pickering A. The purpose of the seismic safety margin review is to determine whether the nuclear plant has sufficient seismic safety margin over its design basis to assure plant safety. In this review process, it is possible to identify the weak links which might limit the seismic performance of critical structures, systems and components. The proposed methodology is a modification the EPRI (Electric Power Research Institute) approach. The methodology includes: the characterization of the site margin earthquake, the definition of the performance criteria for the elements of a success path, and the determination of the seismic withstand capacity. It is proposed that the margin earthquake be established on the basis of using historical records and the regional seismo-tectonic and site specific evaluations. The ability of the components and systems to withstand the margin earthquake is determined by database comparisons, inspection, analysis or testing. An implementation plan for the application of the methodology to the Pickering A NGS is prepared

  2. Containment safety margins

    International Nuclear Information System (INIS)

    Von Riesemann, W.A.

    1980-01-01

    Objective of the Containment Safety Margins program is the development and verification of methodologies which are capable of reliably predicting the ultimate load-carrying capability of light water reactor containment structures under accident and severe environments. The program was initiated in June 1980 at Sandia and this paper addresses the first phase of the program which is essentially a planning effort. Brief comments are made about the second phase, which will involve testing of containment models

  3. Safety margins in deterministic safety analysis

    International Nuclear Information System (INIS)

    Viktorov, A.

    2011-01-01

    The concept of safety margins has acquired certain prominence in the attempts to demonstrate quantitatively the level of the nuclear power plant safety by means of deterministic analysis, especially when considering impacts from plant ageing and discovery issues. A number of international or industry publications exist that discuss various applications and interpretations of safety margins. The objective of this presentation is to bring together and examine in some detail, from the regulatory point of view, the safety margins that relate to deterministic safety analysis. In this paper, definitions of various safety margins are presented and discussed along with the regulatory expectations for them. Interrelationships of analysis input and output parameters with corresponding limits are explored. It is shown that the overall safety margin is composed of several components each having different origins and potential uses; in particular, margins associated with analysis output parameters are contrasted with margins linked to the analysis input. While these are separate, it is possible to influence output margins through the analysis input, and analysis method. Preserving safety margins is tantamount to maintaining safety. At the same time, efficiency of operation requires optimization of safety margins taking into account various technical and regulatory considerations. For this, basic definitions and rules for safety margins must be first established. (author)

  4. Texas curve margin of safety.

    Science.gov (United States)

    2013-01-01

    This software can be used to assist with the assessment of margin of safety for a horizontal curve. It is intended for use by engineers and technicians responsible for safety analysis or management of rural highway pavement or traffic control devices...

  5. Technical specification improvement through safety margin considerations

    International Nuclear Information System (INIS)

    Howard, R.C.; Jansen, R.L.

    1986-01-01

    Westinghouse has developed an approach for utilizing safety analysis margin considerations to improve plant operability through technical specification revision. This approach relies on the identification and use of parameter interrelations and sensitivities to identify acceptable operating envelopes. This paper summarizes technical specification activities to date and presents the use of safety margin considerations as another viable method to obtain technical specification improvement

  6. Time Safety Margin: Theory and Practice

    Science.gov (United States)

    2016-09-01

    Air Education and Training Command Handbook 99-107, T-38 Road to Wings, Randolph Air Force Base, Texas, July 2013. 65 This page was intentionally left...412TW-TIH-16-01 TIME SAFETY MARGIN: THEORY AND PRACTICE WILLIAM R. GRAY, III Chief Test Pilot USAF Test Pilot School SEPTEMBER 2016... Safety Margin: The01y and Practice) was submitted by the Commander, 4 I 2th Test Wing, Edwards AFB, Ca lifornia 93524-6843. Foreign announcement and

  7. Seismic safety margins research program overview

    International Nuclear Information System (INIS)

    Tokarz, F.J.; Smith, P.D.

    1978-01-01

    A multiyear seismic research program has been initiated at the Lawrence Livermore Laboratory. This program, the Seismic Safety Margins Research Program (SSMRP) is funded by the U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research. The program is designed to develop a probabilistic systems methodology for determining the seismic safety margins of nuclear power plants. Phase I, extending some 22 months, began in July 1978 at a funding level of approximately $4.3 million. Here we present an overview of the SSMRP. Included are discussions on the program objective, the approach to meet the program goal and objectives, end products, the probabilistic systems methodology, and planned activities for Phase I

  8. Structural safety - Is the safety margin measurable

    International Nuclear Information System (INIS)

    Rintamaa, R.

    1992-01-01

    In ensuring the structural safety of the nuclear components one must be aware of the uncertainties related to the material deorientation, loadings and other operational conditions, geometrical dimensions as well as the service environment. Furthermore, the validation of the analysis tools and procedures is of great importance in overall safety assessment of a pressure retaining component. In order to identify and quantify the concerns and risks arising from the uncertainties in the safety related issue intensive research is being carried out all over the world, in particular, on the ageing, plant life extension and management of old nuclear power plants. The presentation includes a general survey of the factors relevant to the assessment of safe and reliable operation of a nuclear component throughout its planned service life. Certain aspects are outlined based on the research work being carried out at the Technical Research Centre of Finland (VTT)(orig.)

  9. RISK-INFORMED SAFETY MARGIN CHARACTERIZATION

    International Nuclear Information System (INIS)

    Dinh, Nam; Szilard, Ronaldo

    2009-01-01

    The concept of safety margins has served as a fundamental principle in the design and operation of commercial nuclear power plants (NPPs). Defined as the minimum distance between a system's 'loading' and its 'capacity', plant design and operation is predicated on ensuring an adequate safety margin for safety-significant parameters (e.g., fuel cladding temperature, containment pressure, etc.) is provided over the spectrum of anticipated plant operating, transient and accident conditions. To meet the anticipated challenges associated with extending the operational lifetimes of the current fleet of operating NPPs, the United States Department of Energy (USDOE), the Idaho National Laboratory (INL) and the Electric Power Research Institute (EPRI) have developed a collaboration to conduct coordinated research to identify and address the technological challenges and opportunities that likely would affect the safe and economic operation of the existing NPP fleet over the postulated long-term time horizons. In this paper we describe a framework for developing and implementing a Risk-Informed Safety Margin Characterization (RISMC) approach to evaluate and manage changes in plant safety margins over long time horizons

  10. Quantifying Safety Margin Using the Risk-Informed Safety Margin Characterization (RISMC)

    Energy Technology Data Exchange (ETDEWEB)

    Grabaskas, David; Bucknor, Matthew; Brunett, Acacia; Nakayama, Marvin

    2015-04-26

    The Risk-Informed Safety Margin Characterization (RISMC), developed by Idaho National Laboratory as part of the Light-Water Reactor Sustainability Project, utilizes a probabilistic safety margin comparison between a load and capacity distribution, rather than a deterministic comparison between two values, as is usually done in best-estimate plus uncertainty analyses. The goal is to determine the failure probability, or in other words, the probability of the system load equaling or exceeding the system capacity. While this method has been used in pilot studies, there has been little work conducted investigating the statistical significance of the resulting failure probability. In particular, it is difficult to determine how many simulations are necessary to properly characterize the failure probability. This work uses classical (frequentist) statistics and confidence intervals to examine the impact in statistical accuracy when the number of simulations is varied. Two methods are proposed to establish confidence intervals related to the failure probability established using a RISMC analysis. The confidence interval provides information about the statistical accuracy of the method utilized to explore the uncertainty space, and offers a quantitative method to gauge the increase in statistical accuracy due to performing additional simulations.

  11. Task Group on Safety Margins Action Plan (SMAP). Safety Margins Action Plan - Final Report

    International Nuclear Information System (INIS)

    Hrehor, Miroslav; Gavrilas, Mirela; Belac, Josef; Sairanen, Risto; Bruna, Giovanni; Reocreux, Michel; Touboul, Francoise; Krzykacz-Hausmann, B.; Park, Jong Seuk; Prosek, Andrej; Hortal, Javier; Sandervaag, Odbjoern; Zimmerman, Martin

    2007-01-01

    The international nuclear community has expressed concern that some changes in existing plants could challenge safety margins while fulfilling all the regulatory requirements. In 1998, NEA published a report by the Committee on Nuclear Regulatory Activities on Future Nuclear Regulatory Challenges. The report recognized 'Safety margins during more exacting operating modes' as a technical issue with potential regulatory impact. Examples of plant changes that can cause such exacting operating modes include power up-rates, life extension or increased fuel burnup. In addition, the community recognized that the cumulative effects of simultaneous changes in a plant could be larger than the accumulation of the individual effects of each change. In response to these concerns, CSNI constituted the safety margins action plan (SMAP) task group with the following objectives: 'To agree on a framework for integrated assessments of the changes to the overall safety of the plant as a result of simultaneous changes in plant operation / condition; To develop a CSNI document which can be used by member countries to assess the effect of plant change on the overall safety of the plant; To share information and experience.' The two approaches to safety analysis, deterministic and probabilistic, use different methods and have been developed mostly independently of each other. This makes it difficult to assure consistency between them. As the trend to use information on risk (where the term risk means results of the PSA/PRA analysis) to support regulatory decisions is growing in many countries, it is necessary to develop a method of evaluating safety margin sufficiency that is applicable to both approaches and, whenever possible, integrated in a consistent way. Chapter 2 elaborates on the traditional view of safety margins and the means by which they are currently treated in deterministic analyses. This chapter also discusses the technical basis for safety limits as they are used today

  12. Safety margins in older adults increase with improved control of a dynamic object

    Science.gov (United States)

    Hasson, Christopher J.; Sternad, Dagmar

    2014-01-01

    Older adults face decreasing motor capabilities due to pervasive neuromuscular degradations. As a consequence, errors in movement control increase. Thus, older individuals should maintain larger safety margins than younger adults. While this has been shown for object manipulation tasks, several reports on whole-body activities, such as posture and locomotion, demonstrate age-related reductions in safety margins. This is despite increased costs for control errors, such as a fall. We posit that this paradox could be explained by the dynamic challenge presented by the body or also an external object, and that age-related reductions in safety margins are in part due to a decreased ability to control dynamics. To test this conjecture we used a virtual ball-in-cup task that had challenging dynamics, yet afforded an explicit rendering of the physics and safety margin. The hypotheses were: (1) When manipulating an object with challenging dynamics, older adults have smaller safety margins than younger adults. (2) Older adults increase their safety margins with practice. Nine young and 10 healthy older adults practiced moving the virtual ball-in-cup to a target location in exactly 2 s. The accuracy and precision of the timing error quantified skill, and the ball energy relative to an escape threshold quantified the safety margin. Compared to the young adults, older adults had increased timing errors, greater variability, and decreased safety margins. With practice, both young and older adults improved their ability to control the object with decreased timing errors and variability, and increased their safety margins. These results suggest that safety margins are related to the ability to control dynamics, and may explain why in tasks with simple dynamics older adults use adequate safety margins, but in more complex tasks, safety margins may be inadequate. Further, the results indicate that task-specific training may improve safety margins in older adults. PMID:25071566

  13. Safety Margins in Older Adults Increase with Improved Control of a Dynamic Object

    Directory of Open Access Journals (Sweden)

    Christopher James Hasson

    2014-07-01

    Full Text Available Older adults face decreasing motor capabilities due to pervasive neuromuscular degradations. As a consequence errors in movement control increase. Thus, older individuals should maintain larger safety margins than younger adults. While this has been shown for object manipulation tasks, several reports on whole-body activities, such as posture and locomotion, however demonstrate age-related reductions in safety margins. This is despite increased costs for control errors, such as a fall. We posit that this paradox could be explained by the dynamic challenge presented by the body or an external object, and that age-related reductions in safety margins are in part due to a decreased ability to control dynamics. To test this conjecture we used a virtual ball-in-cup task that had challenging dynamics, yet afforded an explicit rendering of the physics and safety margin. The hypotheses were: 1 When manipulating an object with challenging dynamics, older adults have smaller safety margins than younger adults. 2 Older adults increase their safety margins with practice. Nine young and 10 healthy older adults practiced moving the virtual ball-in-cup to a target location in exactly two seconds. The accuracy and precision of the timing error quantified skill and the ball energy relative to an escape threshold quantified the safety margin. Compared to the young adults, older adults had increased timing errors, greater variability, and decreased safety margins. With practice, both young and older adults improved their ability to control the object with decreased timing errors and variability, and increased their safety margins. These results suggest that safety margins are related to the ability to control dynamics, and may explain why in tasks with simple dynamics older adults use adequate safety margins, but in more complex tasks, safety margins may be inadequate. Further, the results indicate that task-specific training may improve safety margins in older

  14. Extensive formation of sinkholes in unconsolidated rock due to underground erosive removal of sand at a marginal batter of an opencast mine - causes, process and geotechnical safety measures. Grossflaechige Erdfallbildungen im Lockergestein durch unterirdische erosive Ausraeumung von Sand and einer Tagebauendboeschung - Ursachen, Verlauf und geotechnische Sicherung

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, H

    1991-08-01

    When the ground water rose in the marginal batter of an opencast mine damage occurred. This was caused by the processes of internal erosion and suffusion in fine sand layers of slight thickness and by the disintegration of the overlying strata due to the formation of sinkholes. Effective safety measures involved lowering the ground-water level in the zone immediately in front of the area in question and installing an auxiliary filter unit at the marginal batter. (orig.).

  15. Anticipation and the adaptive control of safety margins in driving

    NARCIS (Netherlands)

    van der Hulst, M.; Meijman, T.F.; Rothengatter, J.A.

    Driving is a task that requires the timely detection of critical events and relevant changes in traffic circumstances. Adaptation of speed and safety margins allows drivers to control the time available to react to potential hazards. One of the basic safety margins in driving is the time headway

  16. Analysis of safety margins for PuO2 containers

    International Nuclear Information System (INIS)

    Hubert, P.; Tomachevsky, E.

    1987-11-01

    In the regular manner the containers for PuO 2 transport are type B(U) and give satisfaction to the AIEA proofs. However the vigour of this conception's containers and the analysis of other radioactive containers permit to think that large safety margins exist. In this paper, the importance and the kind of these margins are studied [fr

  17. Safety margins of operating reactors. Analysis of uncertainties and implications for decision making

    International Nuclear Information System (INIS)

    2003-01-01

    Maintaining safety in the design and operation of nuclear power plants (NPPs) is a very important task under the conditions of a challenging environment, affected by the deregulated electricity market and implementation of risk informed regulations. In Member States, advanced computer codes are widely used as safety analysis tools in the framework of licensing of new NPP projects, safety upgrading programmes of existing NPPs, periodic safety reviews, renewal of operating licences, use of the safety margins for reactor power uprating, better utilization of nuclear fuel and higher operational flexibility, for justification of lifetime extensions, development of new emergency operating procedures, analysis of operational events, and development of accident management programmes. The issue of inadequate quality of safety analysis is becoming important due to a general tendency to use advanced tools for better establishment and utilization of safety margins, while the existence of such margins assure that NPPs operate safely in all modes of operation and at all times. The most important safety margins relate to physical barriers against release of radioactive material, such as fuel matrix and fuel cladding, reactor coolant system boundary, and the containment. Typically, safety margins are determined with use of computational tools for safety analysis. Advanced best estimate computer codes are suggested e.g. in the IAEA Safety Guide on Safety Assessment and Verification for Nuclear Power Plants to be used for current safety analysis. Such computer codes require their careful application to avoid unjustified reduction in robustness of the reactor safety. The issue of uncertainties in safety analyses and their impact on evaluation of safety margins is addressed in a number of IAEA guidance documents, in particular in the Safety Report on Accident Analysis for Nuclear Power Plants. It is also discussed in various technical meetings and workshops devoted to this area. The

  18. Seismic and tsunami safety margin assessment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    Nuclear Regulation Authority is going to establish new seismic and tsunami safety guidelines to increase the safety of NPPs. The main purpose of this research is testing structures/components important to safety and tsunami resistant structures/components, and evaluating the capacity of them against earthquake and tsunami. Those capacity data will be utilized for the seismic and tsunami back-fit review based on the new seismic and tsunami safety guidelines. The summary of the program in 2012 is as follows. 1. Component seismic capacity test and quantitative seismic capacity evaluation. PWR emergency diesel generator partial-model seismic capacity tests have been conducted and quantitative seismic capacities have been evaluated. 2. Seismic capacity evaluation of switching-station electric equipment. Existing seismic test data investigation, specification survey and seismic response analyses have been conducted. 3. Tsunami capacity evaluation of anti-inundation measure facilities. Tsunami pressure test have been conducted utilizing a small breakwater model and evaluated basic characteristics of tsunami pressure against seawall structure. (author)

  19. Seismic and tsunami safety margin assessment

    International Nuclear Information System (INIS)

    2013-01-01

    Nuclear Regulation Authority is going to establish new seismic and tsunami safety guidelines to increase the safety of NPPs. The main purpose of this research is testing structures/components important to safety and tsunami resistant structures/components, and evaluating the capacity of them against earthquake and tsunami. Those capacity data will be utilized for the seismic and tsunami back-fit review based on the new seismic and tsunami safety guidelines. The summary of the program in 2012 is as follows. 1. Component seismic capacity test and quantitative seismic capacity evaluation. PWR emergency diesel generator partial-model seismic capacity tests have been conducted and quantitative seismic capacities have been evaluated. 2. Seismic capacity evaluation of switching-station electric equipment. Existing seismic test data investigation, specification survey and seismic response analyses have been conducted. 3. Tsunami capacity evaluation of anti-inundation measure facilities. Tsunami pressure test have been conducted utilizing a small breakwater model and evaluated basic characteristics of tsunami pressure against seawall structure. (author)

  20. EPR meeting international safety standards with margin

    International Nuclear Information System (INIS)

    Mazurkiewicz, S.M.; Brauns, J.; Blombach, J.

    2005-01-01

    The EPR provides technology that offers a solution to the market's need for safe, economic power. The EPR was originally developed through a joint effort between Framatome ANP and Siemens by incorporating the best technological features from the French and German nuclear reactor fleets into a cost-competitive product capable of international licensing. As such, the EPR is a global product with commercial units currently being built in Finland at the Olkiluoto site, and planned for France, at the Flamanville site. Framatome ANP has recently proposed four EPR units to China in response to a request for vendor bids. In addition, Framatome ANP has announced their intent to pursue design certification with the United States Nuclear Regulatory Commission (NRC). This paper discusses how EPR's innovative safety philosophy ensures compliance with international safety standards for advanced light-water reactors (ALWRs). (author)

  1. EPR meeting international safety standards with margin

    International Nuclear Information System (INIS)

    Mazurkiewicz, S.M.; Brauns, J.; Blombach, J.

    2005-01-01

    The EPR provides technology that offers a solution to the market's need for safe, economic power. The EPR was originally developed through a joint effort between Framatome ANP and Siemens by incorporating the best technological features from the French and German nuclear reactor fleets into a cost-competitive product capable of international licensing. As such, the EPR is a global product with commercial units currently being built in Finland at the Olkiluoto site, and planned for France, at the Flamanville site. Framatome ANP has recently proposed four EPR units to China in response to a request for vendor bids. In addition, Framatome ANP has announced their intent to pursue design certification in with the United States Nuclear Regulatory Commission (NRC). This paper discusses how EPR's innovative safety philosophy ensures compliance with international safety standards for advanced light-water reactors (ALWRs). (author)

  2. Safety margins associated with containment structures under dynamic loading

    International Nuclear Information System (INIS)

    Lu, S.C.

    1978-01-01

    A technical basis for assessing the true safety margins of containment structures involved with MARK I boiling water reactor reevaluation activities is presented. It is based on the results of a plane-strain, large displacement, elasto-plastic, finite-element analysis of a thin cylindrical shell subjected to external and internal pressure pulses. An analytical procedure is presented for estimating the ultimate load capacity of the thin shell structure, and subsequently, for quantifying the design margins of safety for the type of loads under consideration. For defining failure of structures, a finite strain failure criterion is derived that accounts for multiaxiality effects

  3. Criticality safety margins for mixtures of fissionable materials

    International Nuclear Information System (INIS)

    Williamson, T.G.; Mincey, J.F.

    1992-01-01

    In the determination of criticality safety margins, approximations for combinations of fissile and fissionable isotopes are sometimes used that go by names such as the rule of fractions or equivalency relations. Use of the rule of fractions to ensure criticality safety margins was discussed in an earlier paper. The purpose of this paper is to correct errors and to clarify some of the implications. Deviations of safety margins from those calculated by the rule of fractions are still noted; however, the deviations are less severe. Caution in applying such rules is still urged. In general, these approximations are based on American National Standard ANSI/ANS-8.15, Sec. 5.2. This section allows that ratios of material masses to their limits may be summed for fissile nuclides in aqueous solutions. It also allows the addition of nonfissile nuclides if an aqueous moderator is present and addresses the effects of infinite water or equivalent reflector. Water-reflected binary combinations of aqueous solutions of fissile materials, as well as binary combinations of fissile and fissionable metals, were considered. Some combinations were shown to significantly decrease the margin of subcriticality compared to the single-unit margins. In this study, it is confirmed that some combinations of metal units in an optimum geometry may significantly decrease the margin of subcriticality. For some combinations of aqueous solutions of fissile materials, the margin of subcriticality may also be reduced by very small amounts. The conclusion of Ref. 1 that analysts should be careful in applying equivalency relations for combining materials remains valid and sound advice. The ANSI/ANS standard, which allows the use of ratios of masses to their limits, applies to aqueous, fully water-reflected, single-unit solutions. Extensions to other situations should be considered with extreme care

  4. Statistical margin to DNB safety analysis approach for LOFT

    International Nuclear Information System (INIS)

    Atkinson, S.A.

    1982-01-01

    A method was developed and used for LOFT thermal safety analysis to estimate the statistical margin to DNB for the hot rod, and to base safety analysis on desired DNB probability limits. This method is an advanced approach using response surface analysis methods, a very efficient experimental design, and a 2nd-order response surface equation with a 2nd-order error propagation analysis to define the MDNBR probability density function. Calculations for limiting transients were used in the response surface analysis thereby including transient interactions and trip uncertainties in the MDNBR probability density

  5. Seismic Safety Margins Research Program: a concluding look

    International Nuclear Information System (INIS)

    Cummings, G.E.

    1984-01-01

    The Seismic Safety Margins Research Program (SSMRP) was started in 1978 with the goal of developing tools and data bases to compute the probability of earthquake - caused radioactive release from commercial nuclear power plants. These tools and data bases were to help NRC to assess seismic safety at nuclear plants. The methodology to be used was finalized in 1982 and applied to the Zion Nuclear Power Station. The SSMRP will be completed this year with the development of a more simplified method of analysis and a demonstration of its use on Zion. This simplified method is also being applied to a boiling-water-reactor, LaSalle

  6. A dynamic probabilistic safety margin characterization approach in support of Integrated Deterministic and Probabilistic Safety Analysis

    International Nuclear Information System (INIS)

    Di Maio, Francesco; Rai, Ajit; Zio, Enrico

    2016-01-01

    The challenge of Risk-Informed Safety Margin Characterization (RISMC) is to develop a methodology for estimating system safety margins in the presence of stochastic and epistemic uncertainties affecting the system dynamic behavior. This is useful to support decision-making for licensing purposes. In the present work, safety margin uncertainties are handled by Order Statistics (OS) (with both Bracketing and Coverage approaches) to jointly estimate percentiles of the distributions of the safety parameter and of the time required for it to reach these percentiles values during its dynamic evolution. The novelty of the proposed approach consists in the integration of dynamic aspects (i.e., timing of events) into the definition of a dynamic safety margin for a probabilistic Quantification of Margin and Uncertainties (QMU). The system here considered for demonstration purposes is the Lead–Bismuth Eutectic- eXperimental Accelerator Driven System (LBE-XADS). - Highlights: • We integrate dynamic aspects into the definition of a safety margins. • We consider stochastic and epistemic uncertainties affecting the system dynamics. • Uncertainties are handled by Order Statistics (OS). • We estimate the system grace time during accidental scenarios. • We apply the approach to an LBE-XADS accidental scenario.

  7. Safety margin evaluation concepts for plant Up rates and life extension. Results of the OECD/NEA/CSNI working group on Safety Margin Action Plan (SMAP)

    International Nuclear Information System (INIS)

    Belac, J

    2006-01-01

    This presentation summarizes results of the OECD/NEA/CSNI working group on Safety Margin Action Plan (SMAP) aimed to develop generalized safety margin concept and means of its quantification for the process of evaluating plant safety in the frame of plant life extension and power up rating activities to be used by OECD member countries. (author)

  8. Developing Probabilistic Safety Performance Margins for Unknown and Underappreciated Risks

    Science.gov (United States)

    Benjamin, Allan; Dezfuli, Homayoon; Everett, Chris

    2015-01-01

    Probabilistic safety requirements currently formulated or proposed for space systems, nuclear reactor systems, nuclear weapon systems, and other types of systems that have a low-probability potential for high-consequence accidents depend on showing that the probability of such accidents is below a specified safety threshold or goal. Verification of compliance depends heavily upon synthetic modeling techniques such as PRA. To determine whether or not a system meets its probabilistic requirements, it is necessary to consider whether there are significant risks that are not fully considered in the PRA either because they are not known at the time or because their importance is not fully understood. The ultimate objective is to establish a reasonable margin to account for the difference between known risks and actual risks in attempting to validate compliance with a probabilistic safety threshold or goal. In this paper, we examine data accumulated over the past 60 years from the space program, from nuclear reactor experience, from aircraft systems, and from human reliability experience to formulate guidelines for estimating probabilistic margins to account for risks that are initially unknown or underappreciated. The formulation includes a review of the safety literature to identify the principal causes of such risks.

  9. Example of a SWOV (Institute for Road Safety Research) safety study : "Avenida Marginal", Lisbon 1989.

    NARCIS (Netherlands)

    Janssen, S.T.M.C.

    1991-01-01

    This paper describes the accident study on the Marginal Road between Alges and Cascais in Portugal. The aim of this study was to produce a philosophy for a strategy to select the best safety measures out of several which had already been proposed. The general point of departure in this philosophy is

  10. Seismic safety margin research program. Program plan, Revision II

    International Nuclear Information System (INIS)

    Smith, P.D.; Tokarz, F.J.; Bernreuter, D.L.; Cummings, G.E.; Chou, C.K.; Vagliente, V.N.; Johnson, J.J.; Dong, R.G.

    1978-01-01

    The document has been prepared pursuant to the second meeting of the Senior Research Review Group of the Seismic Safety Margin Research Program (SSMRP), which was held on June 15, 16, 1978. The major portion of the material contained in the document is descriptions of specific subtasks to be performed on the SSMRP. This is preceded by a brief discussion of the objective of the SSMRP and the approach to be used. Specific subtasks to be performed in Phase I of the SSMRP are as follows: (1) plant/site selection, (2) seismic input, (3) soil structure interaction, (4) structural building response, (5) structural sub-system response, (6) fragility, (7) system analysis, and (8) Phase II task definition

  11. Seismic safety margins research program. Phase I final report - Overview

    International Nuclear Information System (INIS)

    Smith, P.D.; Dong, R.G.; Bernreuter, D.L.; Bohn, M.P.; Chuang, T.Y.; Cummings, G.E.; Johnson, J.J.; Mensing, R.W.; Wells, J.E.

    1981-04-01

    The Seismic Safety Margins Research Program (SSMRP) is a multiyear, multiphase program whose overall objective is to develop improved methods for seismic safety assessments of nuclear power plants, using a probabilistic computational procedure. The program is being carried out at the Lawrence Livermore National Laboratory and is sponsored by the U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research. Phase I of the SSMRP was successfully completed in January 1981: A probabilistic computational procedure for the seismic risk assessment of nuclear power plants has been developed and demonstrated. The methodology is implemented by three computer programs: HAZARD, which assesses the seismic hazard at a given site, SMACS, which computes in-structure and subsystem seismic responses, and SEISIM, which calculates system failure probabilities and radioactive release probabilities, given (1) the response results of SMACS, (2) a set of event trees, (3) a family of fault trees, (4) a set of structural and component fragility descriptions, and (5) a curve describing the local seismic hazard. The practicality of this methodology was demonstrated by computing preliminary release probabilities for Unit 1 of the Zion Nuclear Power Plant north of Chicago, Illinois. Studies have begun aimed at quantifying the sources of uncertainty in these computations. Numerous side studies were undertaken to examine modeling alternatives, sources of error, and available analysis techniques. Extensive sets of data were amassed and evaluated as part of projects to establish seismic input parameters and to produce the fragility curves. (author)

  12. Safety assessment for the passive system of the nuclear power plants (NPPs) using safety margin estimation

    International Nuclear Information System (INIS)

    Woo, Tae-Ho; Lee, Un-Chul

    2010-01-01

    The probabilistic safety assessment (PSA) for gas-cooled nuclear power plants has been investigated where the operational data are deficient, because there is not any commercial gas-cooled nuclear power plant. Therefore, it is necessary to use the statistical data for the basic event constructions. Several estimations for the safety margin are introduced for the quantification of the failure frequency in the basic event, which is made by the concept of the impact and affordability. Trend of probability of failure (TPF) and fuzzy converter (FC) are introduced using the safety margin, which shows the simplified and easy configurations for the event characteristics. The mass flow rate in the natural circulation is studied for the modeling. The potential energy in the gravity, the temperature and pressure in the heat conduction, and the heat transfer rate in the internal stored energy are also investigated. The values in the probability set are compared with those of the fuzzy set modeling. Non-linearity of the safety margin is expressed by the fuzziness of the membership function. This artificial intelligence analysis of the fuzzy set could enhance the reliability of the system comparing to the probabilistic analysis.

  13. Safety margins and retrofit. The technical calculation perspective; Sicherheitsmargen durch Nachruestung aus Sicht der technischen Berechnung

    Energy Technology Data Exchange (ETDEWEB)

    Daichendt, Matthias [Kraftanlagen Heidelberg GmbH, Heidelberg (Germany). Systemtechnik - Technische Berechnungen

    2016-01-15

    Safety margins are an essential factor of the safety philosophy for nuclear power plants. They support to cover future requirements even today. The basic safety concept is one key topic as also aspects of process engineering, the dimensioning and mechanical analysis of systems and ageing management. Calculations with today's capabilities are an integral part of the determination of safety margins. They can be used to analyse and to assess retrofit measures.

  14. PGSFR Core Thermal Design Procedure to Evaluate the Safety Margin

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sun Rock; Kim, Sang-Ji [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The Korea Atomic Energy Research Institute (KAERI) has performed a SFR design with the final goal of constructing a prototype plant by 2028. The main objective of the SFR prototype plant is to verify the TRU metal fuel performance, reactor operation, and transmutation ability of high-level wastes. The core thermal design is to ensure the safe fuel performance during the whole plant operation. Compared to the critical heat flux in typical light water reactors, nuclear fuel damage in SFR subassemblies arises from a creep induced failure. The creep limit is evaluated based on the maximum cladding temperature, power, neutron flux, and uncertainties in the design parameters, as shown in Fig. 1. In this work, the core thermal design procedures are compared to verify the present PGSFR methodology based on the nuclear plant design criteria/guidelines and previous SFR thermal design methods. The PGSFR core thermal design procedure is verified based on the nuclear plant design criteria/guidelines and previous methods in LWRs and SFRs. The present method aims to directly evaluate the fuel cladding failure and to assure more safety margin. The 2 uncertainty is similar to 95% one-side tolerance limit of 1.96 in LWRs. The HCFs, ITDP, and MCM reveal similar uncertainty propagation for cladding midwall temperature for typical SFR conditions. The present HCFs are mainly employed from the CRBR except the fuel-related uncertainty such as an incorrect fuel distribution. Preliminary PGSFR specific HCFs will be developed by the end of 2015.

  15. Seismic safety margin assessment program (Annual safety research report, JFY 2010)

    International Nuclear Information System (INIS)

    Suzuki, Kenichi; Iijima, Toru; Inagaki, Masakatsu; Taoka, Hideto; Hidaka, Shinjiro

    2011-01-01

    Seismic capacity test data, analysis method and evaluation code provided by Seismic Safety Margin Assessment Program have been utilized for the support of seismic back-check evaluation of existing plants. The summary of the program in 2010 is as follows. 1. Component seismic capacity test and quantitative seismic capacity evaluation. Many seismic capacity tests of various snubbers were conducted and quantitative seismic capacities were evaluated. One of the emergency diesel generator partial-model seismic capacity tests was conducted and quantitative seismic capacity was evaluated. Some of the analytical evaluations of piping-system seismic capacities were conducted. 2. Analysis method for minute evaluation of component seismic response. The difference of seismic response of large components such as primary containment vessel and reactor pressure vessel when they were coupled with 3-dimensional FEM building model or 1-dimensional lumped mass building model, was quantitatively evaluated. 3. Evaluation code for quantitative evaluation of seismic safety margin of systems, structures and components. As the example, quantitative evaluation of seismic safety margin of systems, structures and components were conducted for the reference plant. (author)

  16. Treatment of Passive Component Reliability in Risk-Informed Safety Margin Characterization FY 2010 Report

    Energy Technology Data Exchange (ETDEWEB)

    Robert W Youngblood

    2010-09-01

    The Risk-Informed Safety Margin Characterization (RISMC) pathway is a set of activities defined under the U.S. Department of Energy (DOE) Light Water Reactor Sustainability Program. The overarching objective of RISMC is to support plant life-extension decision-making by providing a state-of-knowledge characterization of safety margins in key systems, structures, and components (SSCs). A technical challenge at the core of this effort is to establish the conceptual and technical feasibility of analyzing safety margin in a risk-informed way, which, unlike conventionally defined deterministic margin analysis, is founded on probabilistic characterizations of SSC performance.

  17. Seismic Safety Margins Research Program (Phase I). Project IV. Structural building response; Structural Building Response Review

    International Nuclear Information System (INIS)

    Healey, J.J.; Wu, S.T.; Murga, M.

    1980-02-01

    As part of the Phase I effort of the Seismic Safety Margins Research Program (SSMRP) being performed by the University of California Lawrence Livermore Laboratory for the US Nuclear Regulatory Commission, the basic objective of Subtask IV.1 (Structural Building Response Review) is to review and summarize current methods and data pertaining to seismic response calculations particularly as they relate to the objectives of the SSMRP. This material forms one component in the development of the overall computational methodology involving state of the art computations including explicit consideration of uncertainty and aimed at ultimately deriving estimates of the probability of radioactive releases due to seismic effects on nuclear power plant facilities

  18. Summary report on the Seismic Safety Margins Research Program

    International Nuclear Information System (INIS)

    Cummings, G.E.

    1986-01-01

    The Seismic Safety Margins Research Program (SSMRP) was a program to develop a complete, fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake-induced radioactive release from a commercial nuclear power plant. The SSMRP was the first effort to trace seismically induced failure modes in a reactor system down to the individual component level, and to take into account common-cause earthquake-induced failures at the component level. This report summarizes methods and results generated by SSMRP. The SSMRP method makes use of three computer codes, HAZARD, SMACS and SEISIM to calculate ground motion acceleration time histories, structure and component responses and failure, and radioactive release probabilities. To demonstrate the methodology, an analysis was done of the Zion Nuclear Power Plant. The median frequency of core melt was computed to be 3E-5 per year, with upper (90%) and lower (10%) bounds of 8E-4 and 6E-7 per year. The main contribution to risk came from earthquakes about 2 through 4 times the design basis earthquake level. Risk was dominated by structural and inter-building piping failures and loss of off-site power. Sensitivity studies were undertaken to test assumptions and modeling procedures relative to soil-structure interaction effects, feed-and-bleed cooling, and structural failures. Assumptions made could have an order-of-magnitude effect on core melt frequency. Also, guidelines were developed for simplifying the SSMRP method, and importance rankings were generated based on the Zion analysis. 56 refs., 6 figs

  19. Seismic safety margins research program. Project I SONGS 1 AFWS Project

    International Nuclear Information System (INIS)

    Chuang, T.Y.; Smith, P.D.; Dong, R.G.; Bernreuter, D.L.; Bohn, M.P.; Cummings, G.E.; Wells, J.E.

    1981-01-01

    The seismic qualification requirements of auxiliary feedwater systems (AFWS) of Pressurized Water Reactors (PWR) were developed over a number of years. These are formalized in the publication General Design Criteria (Appendix A to 10CFR50). The full recognition of the system as an engineered safety feature did not occur until publication of the Standard Review Plan (1975). Efforts to determine how to backfit seismic requirements to earlier plants has been undertaken primarily in the Systematic Evaluation Program (SEP) for a limited number of operating reactors. Nuclear Reactor Research (RES) and NRR have requested LLNL to perform a probabilistic study on the AFWS of San Onofre Nuclear Generating Station (SONGS) Unit 1 utilizing the tools developed by the Seismic Safety Margins Research Program (SSMRP). The main objectives of this project are to: identify the weak links of AFWS; compare the failure probabilities of SONGS 1 and Zion 1 AFWS: and compare the seismic responses due to different input spectra and design values

  20. Improving safety margin of LWRs by rethinking the emergency core cooling system criteria and safety system capacity

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youho, E-mail: euo@kaist.ac.kr; Kim, Bokyung, E-mail: bkkim2@kaist.ac.kr; NO, Hee Cheon, E-mail: hcno@kaist.ac.kr

    2016-10-15

    Highlights: • Zircaloy embrittlement criteria can increase to 1370 °C for CP-ECR lower than 13%. • The draft ECCS criteria of U.S. NRC allow less than 5% in power margin. • The Japanese fracture-based criteria allow around 5% in power margin. • Increasing SIT inventory is effective in assuring safety margin for power uprates. - Abstract: This study investigates the engineering compatibility between emergency core cooling system criteria and safety water injection systems, in the pursuit of safety margin increase of light water reactors. This study proposes an acceptable temperature increase to 1370 °C as long as equivalent cladding reacted calculated by the Cathcart–Pawel equation is below 13%, after an extensive literature review. The influence of different ECCS criteria on the safety margin during large break loss of coolant accident is investigated for OPR-1000 by the system code MARS-KS, implemented with the KINS-REM method. The fracture-based emergency core cooling system (ECCS) criteria proposed in this study are shown to enable power margins up to 10%. In the meantime, the draft U.S. NRC’s embrittlement criteria (burnup-sensitive) and Japanese fracture-based criteria are shown to allow less than 5%, and around 5% of power margins, respectively. Increasing safety injection tank (SIT) water inventory is the key, yet convenient, way of assuring safety margin for power increase. More than 20% increase in the SIT water inventory is required to allow 15% power margins, for the U.S. NRC’s burnup-dependent embrittlement criteria. Controlling SIT water inventory would be a useful option that could allow the industrial desire to pursue power margins even under the recent atmosphere of imposing stricter ECCS criteria for the considerable burnup effects.

  1. ALWR - regulatory stabilization through simplicity, margin, and improved safety

    International Nuclear Information System (INIS)

    Vine, G.; Gray, S.

    1989-01-01

    The Electric Power Research Institute Advanced Light Water Reactor (ALWR) program is discussed with respect to the following topics: fundamental acceptance criteria for the ALWR; program approach; utility steering committee technical guidance; safety principles; utility requirements document; design bases; generic safety issue resolution; reactor accidents prevention and mitigation; and programmatic plans

  2. Evaluation of safety margin of packaging for radioactive materials transport during a severe fire

    International Nuclear Information System (INIS)

    Gilles, P.; Ringot, C.; Warniez, P.; Grall, L.; Perrot, J.

    1986-06-01

    A high safety is obtained by International regulations on radioactive materials transport. It is obtained by packaging design adapted to the potential risk. An important accident to consider is fire for two reasons: the probability of fire occuring for time and temperature higher than conditions applied to type B packaging (800 deg C, 1/2 hr) is not negligible, particularly for air or maritime transport. Safety margins are studied by computation and experimental tests. This report presents results obtained for different types of packagings. Results show a large safety margin [fr

  3. Improved Safety Margin Characterization of Risk from Loss of Offsite Power

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Paul [Texas A & M Univ., College Station, TX (United States)

    2017-11-07

    Original intent: The original intent of this task was “support of the Risk-Informed Safety Margin Characteristic (RISMC) methodology in order” “to address … efficiency of computation so that more accurate and cost-effective techniques can be used to address safety margin characterizations” (S. M. Hess et al., “Risk-Informed Safety Margin Characterization,” Procs. ICONE17, Brussels, July 2009, CD format). It was intended that “in Task 1 itself this improvement will be directed toward upon the very important issue of Loss of Offsite Power (LOOP) events,” more specifically toward the challenge of efficient computation of the multidimensional nonrecovery integral that has been discussed by many previous contributors to the theory of nuclear safety. It was further envisioned that “three different computational approaches will be explored,” corresponding to the three subtasks listed below; deliverables were tied to the individual subtasks.

  4. Light Water Reactor Sustainability Program: Risk-Informed Safety Margins Characterization (RISMC) Pathway Technical Program Plan

    International Nuclear Information System (INIS)

    Smith, Curtis; Rabiti, Cristian; Martineau, Richard; Szilard, Ronaldo

    2016-01-01

    Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). As the current Light Water Reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of Systems, Structures, and Components (SSCs) degradations or failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly ''over-design'' portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as ''safety margin.'' Historically, specific safety margin provisions have been formulated, primarily based on ''engineering judgment.''

  5. Light Water Reactor Sustainability Program: Risk-Informed Safety Margins Characterization (RISMC) Pathway Technical Program Plan

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Curtis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Martineau, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Szilard, Ronaldo [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). As the current Light Water Reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of Systems, Structures, and Components (SSCs) degradations or failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly “over-design” portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as “safety margin.” Historically, specific safety margin provisions have been formulated, primarily based on “engineering judgment.”

  6. Implications of power uprates on safety margins of nuclear power plants. Report of a technical meeting

    International Nuclear Information System (INIS)

    2004-09-01

    The safety of nuclear power plants (NPPs) is based on the defence in depth concept, which relies on successive physical barriers (fuel matrix, cladding, primary system pressure boundary and containment) and other provisions to control radioactive materials and on multiple levels of protection against damage to these barriers. Deterministic safety analysis is an important tool for conforming the adequacy and efficiency of provisions within the defence in depth concept and is used to predict the response of an NPP in predetermined operational states. This type of safety analysis applies a specific set of rules and specific acceptance criteria. Deterministic analysis is typically focused on neutronic, thermohydraulic, radiological and structural aspects, which are often analysed with different computational tools. The advanced computational tools developed for deterministic safety analysis are used for better establishment and utilization of licensing margins or safety margins in consideration of analysis results. At the same time, the existence of such margins ensures that NPPs operate safely in all modes of operation and at all times. To properly assess and address the existing margins and to be able to take advantage of unnecessary conservatisms, state of the art analytical tools intended for safety assessment have been developed. Progress made in the development and application of modern codes for safety analysis and better understanding of phenomena involved in plant design and operation enable the analysts to determine safety margins in consideration of analysis results (licensing margins) with higher precision. There is a general tendency for utilities to take advantage of unnecessarily large conservatisms in safety analyses and to utilize them for reactor power uprates, better utilization of nuclear fuel, higher operational flexibility and for justification of lifetime extension. The present publication sets forth the results of a Technical Meeting on the

  7. Evaluation of the safety margins during shutdown for NPP Krsko

    International Nuclear Information System (INIS)

    Bencik, V.; Sadek, S.; Bajs, T.

    2004-01-01

    In the paper the results of RELAP5/mod3.3 calculations of critical parameters during shutdown for NPP Krsko are presented. Conservative evaluations have been performed at NPP Krsko to determine the minimum configuration of systems required for the safe shutdown operation. Critical parameters in these evaluations are defined as the time to start of the boiling and the time of the core dry-out. In order to have better insight into the available margins, the best estimate code RELAP5/mod3.3 has been used to calculate the same parameters. The analyzed transient is the loss of the Residual Heat Removal (RHR) system, which is used to remove decay heat during shutdown conditions. Several configurations that include open and closed Reactor Coolant System (RCS) were considered in the evaluation. The RELAP5/mod3.3 analysis of the loss of the RHR system has been performed for the following cases: 1) RCS closed and water solid, 2) RCS closed and partially drained, 3) Pressurizer manway open, Steam Generator (SG) U tubes partially drained, 4) Pressurizer and SG manways open, SG U tubes completely drained, 5) Pressurizer manway open, SGs drained, SG nozzle dams installed and 6) SG nozzle dams installed, pressurizer manway open, 1 inch break at RHR pump discharge in the loop with pressurizer. Both RHR trains were assumed in operation prior to start of the transient. The maximum average steady state temperature for all analyzed cases was limited to 333 K. (author)

  8. Savannah River Site TRU Drum Waste Criticality Safety Margin Improvements

    International Nuclear Information System (INIS)

    Blanchard, A.; Hammer, K.

    1998-01-01

    The text of the paper will include an overview of the methodology used to determine the credible scenarios, summary of the analysis of the results, challenges overcome during compliance and implementation, and cost savings due to reduced operational expanses

  9. 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.

  10. Safety margins of PWR irradiated vessels - The Chooz A issue

    Energy Technology Data Exchange (ETDEWEB)

    Hedin, F; Barthelet, B [Electricite de France (EDF), 75 - Paris (France); Guilleret, J C

    1988-12-31

    In 1986, some irradiated specimen of CHOOZ A (SENA) vessel showed a significant excess of {delta} RTNDT to former previsions. The lack of data on one of the two irradiated shells, and discrepancies between dosimeters results and available previous fluence calculations whose accuracy was questionable, cause the safety authorities to require an important complementary work program before putting again the plant on the grid after 1987 fuel reloading. These works are presented and discussed. They lead to a state that a conservative to day value of the vessel RTNDT is 64 degrees Celsius and that there is no underclad defect in the vessel wall and welds. Then the plant was allowed to restart with certitude that vessel irradiation will not impair its lifetime. (author). 4 refs.

  11. Seismic safety margin research program. Program plan, Revision I

    International Nuclear Information System (INIS)

    Smith, P.D.; Tokarz, F.J.; Bernreuter, D.L.; Cummings, G.E.; Chou, C.K.; Vagliente, V.N.

    1978-01-01

    The overall objective of the SSMRP is to develop mathematical models that realistically predict the probability of radioactive releases from seismically induced events in nuclear power plants. These models will be used for four purposes: (1) To perform sensitivity studies to determine the weak links in seismic methodology. The weak links will then be improved by research and development. (2) To estimate the probability of release for a plant. It is believed that the major difficulty in the program will be to obtain acceptably small confidence limits on the probability of release. (3) To estimate the conservatisms in the Standard Review Plan (SRP) seismic design methodology. This will be done by comparing the results of the SRP methodology and the methodology resulting from the research and development in (1). (4) To develop an improved seismic design methodology based on probability. The Phase I objective proposed in this report is to develop mathematical models which will accomplish the purposes No. 1 and No. 2 with simplified assumptions such as linear elastic analysis, limited assessment on component fragility (considering only accident sequences leading to core melt), and simplified safety system

  12. Reload safety evaluation of boron dilution accident related to shutdown margin proportional to boron concentration

    International Nuclear Information System (INIS)

    Zee, Sung Kyun; Lee, Ki Bog; Song, Jae Woong

    1993-06-01

    This report investigates the efficient safety evaluation method and analysis procedure on Boron Dilution Accident(BDA) under the proportional shutdown margin to boron concentration. Also investigated are problems caused by applying this shutdown margin limit. Through this investigation, the safety of Kori-3 Cycle-8, Yonggwang-2 Cycle-7, Kori-4 Cycle-8 and Yonggwang-1 Cycle-8 with respect to BDA is verified. In order to satisfy the shutdown margin requirement in the Technical Specifications, it is shown that the High Flux Alarm at Shutdown Setting for Kori-4 Cycle-8 and Yonggwang-1 Cycle-8 at Mode 5 should be set at 2 or the Technical Specification should be revised. (Author)

  13. ENSI’s synopsis concerning the enhancement of safety margins; Zusammenfassung des ENSI zur Erhöhung der Sicherheitsmargen

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    This press release issued by the Swiss Federal Nuclear Safety Inspectorate ENSI discusses the results of its probabilistic safety analysis on the safety margins for Swiss nuclear power stations that was made after the Fukushima nuclear accident. External incidents such as earthquakes and flooding and their impact on the power stations are analysed by the ERSIM project concerning the enhancement of safety margins. Three shut-down scenarios are discussed. The safety margins with respect to earthquakes and flooding for all four nuclear power station sites are discussed in detail.

  14. Margins of safety provided by COSHH Essentials and the ILO Chemical Control Toolkit.

    Science.gov (United States)

    Jones, Rachael M; Nicas, Mark

    2006-03-01

    COSHH Essentials, developed by the UK Health and Safety Executive, and the Chemical Control Toolkit (Toolkit) proposed by the International Labor Organization, are 'control banding' approaches to workplace risk management intended for use by proprietors of small and medium-sized businesses. Both systems group chemical substances into hazard bands based on toxicological endpoint and potency. COSSH Essentials uses the European Union's Risk-phrases (R-phrases), whereas the Toolkit uses R-phrases and the Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. Each hazard band is associated with a range of airborne concentrations, termed exposure bands, which are to be attained by the implementation of recommended control technologies. Here we analyze the margin of safety afforded by the systems and, for each hazard band, define the minimal margin as the ratio of the minimum airborne concentration that produced the toxicological endpoint of interest in experimental animals to the maximum concentration in workplace air permitted by the exposure band. We found that the minimal margins were always occupational exposure limits, we argue that the minimal margins are better indicators of health protection. Further, given the small margins observed, we feel it is important that revisions of these systems provide the exposure bands to users, so as to permit evaluation of control technology capture efficiency.

  15. Safety Margins and Their Economical Value in a De-regulated Market

    International Nuclear Information System (INIS)

    Vidard, Michel

    2002-01-01

    The definition of safety margins is sometimes ambiguous. Depending on assumptions used to evaluate the evolution of plant parameters and on acceptance criteria, the same design could well turn out to have positive, zero, or negative margin for the same operating situation. Very often, considering that an optimized reactor would have to operate with zero margin compared to at least one safety criterion, designers or utilities considered in their analyses penalizing assumptions. This was done for example either considering reduced component capability or very high core peaking factors, the latter generally exceeding by far what would be anticipated in perturbed situations. This approach has three major drawbacks: -having a reasonable understanding of the real importance of safety margins is difficult, -if a non-conservatism is identified in a methodology, there is a high risk of being in a no-compliance situation from a regulatory standpoint, -it leads to a limitation on allowable electrical output and constraints on technical specifications for example. In a regulated market, such a situation can be tolerable as the final customer has to pay the extra financial burden in any case. In a de-regulated market, the situation is significantly different. The final customer can choose his supplier, and is likely to go to those offering the best prices, i.e. those making optimal use of their available resources. There is so a need for better understanding of real plant capabilities. Revisiting assumptions used for evaluating safety margins is so highly recommended, if not imperative, to electricity companies. This will helpful to reshape company strategies in case of evolution of market conditions. (author)

  16. Plant safety margin against frost damages has declined in Switzerland over the last four decades

    Science.gov (United States)

    Vitasse, Yann; Schneider, Léonard; Klein, Geoffrey; Rixen, Christian; Rebetez, Martine

    2017-04-01

    Winters and early springs have become warmer over the last decades which has in turn promoted earlier plant development in temperate regions. While temperatures will on average continue to increase in the coming decades due to the rise of greenhouse gases concentration in the atmosphere, there is no consensus about how the occurrence of late spring frosts will change. If the frequency and the severity of late spring frosts remain unchanged in the future or advance less than vegetation onset, vulnerable plant organs (young leaves, flowers or dehardened buds) may be more exposed to frost damage. Here we analyzed long-term series of temperature data during the period 1975-2016 at 50 locations in Switzerland. We used different thresholds of growing degree days (GDD) as a proxy for spring phenology of fruit trees based on long-term series of phenological observations. Finally, we tested whether the time lag between the date when the GDD is reached and the latest occurrence of frost has changed over the study period. Overall we found that the safety margin against potential frost damage to plants has slightly decreased during the study period, irrespective of elevation (from 203 to 2283 m). Our results suggest that the cost for preventing frost damages on fruit trees could increase in the coming decades and the introduction of new varieties of fruit trees adapted to warmer climate should be carefully considered as they generally exhibit earlier spring phenology.

  17. Risk-Informed Safety Margin Characterization (RISMC): Integrated Treatment of Aleatory and Epistemic Uncertainty in Safety Analysis

    International Nuclear Information System (INIS)

    Youngblood, R.W.

    2010-01-01

    The concept of 'margin' has a long history in nuclear licensing and in the codification of good engineering practices. However, some traditional applications of 'margin' have been carried out for surrogate scenarios (such as design basis scenarios), without regard to the actual frequencies of those scenarios, and have been carried out with in a systematically conservative fashion. This means that the effectiveness of the application of the margin concept is determined in part by the original choice of surrogates, and is limited in any case by the degree of conservatism imposed on the evaluation. In the RISMC project, which is part of the Department of Energy's 'Light Water Reactor Sustainability Program' (LWRSP), we are developing a risk-informed characterization of safety margin. Beginning with the traditional discussion of 'margin' in terms of a 'load' (a physical challenge to system or component function) and a 'capacity' (the capability of that system or component to accommodate the challenge), we are developing the capability to characterize probabilistic load and capacity spectra, reflecting both aleatory and epistemic uncertainty in system response. For example, the probabilistic load spectrum will reflect the frequency of challenges of a particular severity. Such a characterization is required if decision-making is to be informed optimally. However, in order to enable the quantification of probabilistic load spectra, existing analysis capability needs to be extended. Accordingly, the INL is working on a next-generation safety analysis capability whose design will allow for much more efficient parameter uncertainty analysis, and will enable a much better integration of reliability-related and phenomenology-related aspects of margin.

  18. Improved Safety Margin Characterization of Risk from Loss of Offsite Power

    International Nuclear Information System (INIS)

    Nelson, Paul

    2017-01-01

    Original intent: The original intent of this task was ''support of the Risk-Informed Safety Margin Characteristic (RISMC) methodology in order'' ''to address ... efficiency of computation so that more accurate and cost-effective techniques can be used to address safety margin characterizations'' (S. M. Hess et al., ''Risk-Informed Safety Margin Characterization,'' Procs. ICONE17, Brussels, July 2009, CD format). It was intended that ''in Task 1 itself this improvement will be directed toward upon the very important issue of Loss of Offsite Power (LOOP) events,'' more specifically toward the challenge of efficient computation of the multidimensional nonrecovery integral that has been discussed by many previous contributors to the theory of nuclear safety. It was further envisioned that ''three different computational approaches will be explored,'' corresponding to the three subtasks listed below; deliverables were tied to the individual subtasks.

  19. Safety Margin Assessment (SM2A): Stimulation for Further Development of BEPU Approaches?

    International Nuclear Information System (INIS)

    Zimmermann, Martin A.

    2013-01-01

    During recent years, many nuclear power plants underwent significant modifications, e.g. power up-rating. While compliance with all the deterministic acceptance criteria must be shown during the licensing process, the larger core inventory and the facts that the plant response might get closer to the limits after a power up-rate, suggest an increase of the core damage frequency (CDF) and other possible risk indicators. Hence, a framework to quantitatively assess a change in plant safety margin becomes very desirable. The Committee on the Safety of Nuclear Installations (CSNI) mandated the Safety Margin Action Plan expert group (SMAP) to develop a framework for the assessment of such changes to safety margin. This framework combines PSA and the analytical techniques developed in BEPU. CSNI then mandated the SM2A expert group to especially explore the practicability of the SMAP framework. This pilot study was completed end of 2010. An increase of the (conditional) probability of exceedance for a surrogate acceptance limit (PCT) indicating core damage was successfully evaluated for the selected sequences from several initiating event trees, and it was found that only a restricted number of sequences need to be analyzed. Based on the insights gained from this study, areas of methodology improvement have been identified and related proposals for further R and D work will be discussed. (authors)

  20. Seasonal Variability in Regional Ice Flow Due to Meltwater Injection Into the Shear Margins of Jakobshavn Isbræ

    Science.gov (United States)

    Cavanagh, J. P.; Lampkin, D. J.; Moon, T.

    2017-12-01

    The impact of meltwater injection into the shear margins of Jakobshavn Isbræ via drainage from water-filled crevasses on ice flow is examined. We use Landsat-8 Operational Land Imager panchromatic, high-resolution imagery to monitor the spatiotemporal variability of seven water-filled crevasse ponds during the summers of 2013 to 2015. The timing of drainage from water-filled crevasses coincides with an increase of 2 to 20% in measured ice velocity beyond Jakobshavn Isbræ shear margins, which we define as extramarginal ice velocity. Some water-filled crevasse groups demonstrate multiple drainage events within a single melt season. Numerical simulations show that hydrologic shear weakening due to water-filled crevasse drainage can accelerate extramarginal flow by as much as 35% within 10 km of the margins and enhance mass flux through the shear margins by 12%. This work demonstrates a novel mechanism through which surface melt can influence regional ice flow.

  1. Is it necessary to plan with safety margins for actively scanned proton therapy?

    Science.gov (United States)

    Albertini, F.; Hug, E. B.; Lomax, A. J.

    2011-07-01

    In radiation therapy, a plan is robust if the calculated and the delivered dose are in agreement, even in the case of different uncertainties. The current practice is to use safety margins, expanding the clinical target volume sufficiently enough to account for treatment uncertainties. This, however, might not be ideal for proton therapy and in particular when using intensity modulated proton therapy (IMPT) plans as degradation in the dose conformity could also be found in the middle of the target resulting from misalignments of highly in-field dose gradients. Single field uniform dose (SFUD) and IMPT plans have been calculated for different anatomical sites and the need for margins has been assessed by analyzing plan robustness to set-up and range uncertainties. We found that the use of safety margins is a good way to improve plan robustness for SFUD and IMPT plans with low in-field dose gradients but not necessarily for highly modulated IMPT plans for which only a marginal improvement in plan robustness could be detected through the definition of a planning target volume.

  2. Workshop on Program for Elimination of Requirements Marginal to Safety: Proceedings

    International Nuclear Information System (INIS)

    Dey, M.

    1993-09-01

    These are the proceedings of the Public Workshop on the US Nuclear Regulatory Commission's Program for Elimination of Requirements Marginal to Safety. The workshop was held at the Holiday Inn, Bethesda, on April 27 and 28, 1993. The purpose of the workshop was to provide an opportunity for public and industry input to the program. The workshop addressed the institutionalization of the program to review regulations with the purpose of eliminating those that are marginal. The objective is to avoid the dilution of safety efforts. One session was devoted to discussion of the framework for a performance-based regulatory approach. In addition, panelists and attendees discussed scope, schedules and status of specific regulatory items: containment leakage testing requirements, fire protection requirements, requirements for environmental qualification of electrical equipment, requests for information under 10CFR50.54(f), requirements for combustible gas control systems, and quality assurance requirements

  3. Workshop on Program for Elimination of Requirements Marginal to Safety: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Dey, M. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Safety Issue Resolution; Arsenault, F.; Patterson, M.; Gaal, M. [SCIENTECH, Inc., Rockville, MD (United States)

    1993-09-01

    These are the proceedings of the Public Workshop on the US Nuclear Regulatory Commission`s Program for Elimination of Requirements Marginal to Safety. The workshop was held at the Holiday Inn, Bethesda, on April 27 and 28, 1993. The purpose of the workshop was to provide an opportunity for public and industry input to the program. The workshop addressed the institutionalization of the program to review regulations with the purpose of eliminating those that are marginal. The objective is to avoid the dilution of safety efforts. One session was devoted to discussion of the framework for a performance-based regulatory approach. In addition, panelists and attendees discussed scope, schedules and status of specific regulatory items: containment leakage testing requirements, fire protection requirements, requirements for environmental qualification of electrical equipment, requests for information under 10CFR50.54(f), requirements for combustible gas control systems, and quality assurance requirements.

  4. Margins Associated with Loss of Assured Safety for Systems with Multiple Time-Dependent Failure Modes.

    Energy Technology Data Exchange (ETDEWEB)

    Helton, Jon C. [Arizona State Univ., Tempe, AZ (United States); Brooks, Dusty Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sallaberry, Cedric Jean-Marie. [Engineering Mechanics Corp. of Columbus, OH (United States)

    2018-02-01

    Representations for margins associated with loss of assured safety (LOAS) for weak link (WL)/strong link (SL) systems involving multiple time-dependent failure modes are developed. The following topics are described: (i) defining properties for WLs and SLs, (ii) background on cumulative distribution functions (CDFs) for link failure time, link property value at link failure, and time at which LOAS occurs, (iii) CDFs for failure time margins defined by (time at which SL system fails) – (time at which WL system fails), (iv) CDFs for SL system property values at LOAS, (v) CDFs for WL/SL property value margins defined by (property value at which SL system fails) – (property value at which WL system fails), and (vi) CDFs for SL property value margins defined by (property value of failing SL at time of SL system failure) – (property value of this SL at time of WL system failure). Included in this presentation is a demonstration of a verification strategy based on defining and approximating the indicated margin results with (i) procedures based on formal integral representations and associated quadrature approximations and (ii) procedures based on algorithms for sampling-based approximations.

  5. Seismic Safety Margins Research Program. Phase I. Interim definition of terms

    International Nuclear Information System (INIS)

    Smith, P.D.; Dong, R.G.

    1980-01-01

    This report documents interim definitions of terms in the Seismic Safety Margins Research Program (SSMRP). Intent is to establish a common-based terminology integral to the probabilistic methods that predict more realistically the behavior of nuclear power plants during an earthquake. These definitions are a response to a request by the Nuclear Regulatory Commission Advisory Committee on Reactor Safeguards at its meeting held November 15-16, 1979

  6. A soft-contact model for computing safety margins in human prehension.

    Science.gov (United States)

    Singh, Tarkeshwar; Ambike, Satyajit

    2017-10-01

    The soft human digit tip forms contact with grasped objects over a finite area and applies a moment about an axis normal to the area. These moments are important for ensuring stability during precision grasping. However, the contribution of these moments to grasp stability is rarely investigated in prehension studies. The more popular hard-contact model assumes that the digits exert a force vector but no free moment on the grasped object. Many sensorimotor studies use this model and show that humans estimate friction coefficients to scale the normal force to grasp objects stably, i.e. the smoother the surface, the tighter the grasp. The difference between the applied normal force and the minimal normal force needed to prevent slipping is called safety margin and this index is widely used as a measure of grasp planning. Here, we define and quantify safety margin using a more realistic contact model that allows digits to apply both forces and moments. Specifically, we adapt a soft-contact model from robotics and demonstrate that the safety margin thus computed is a more accurate and robust index of grasp planning than its hard-contact variant. Previously, we have used the soft-contact model to propose two indices of grasp planning that show how humans account for the shape and inertial properties of an object. A soft-contact based safety margin offers complementary insights by quantifying how humans may account for surface properties of the object and skin tissue during grasp planning and execution. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Reliability-based approaches for safety margin assessment in the French nuclear industry

    International Nuclear Information System (INIS)

    Ardillon, E.; Barthelet, B.; Meister, E.; Cambefort, P.; Hornet, P.; Le Delliou, P.

    2003-01-01

    The prevention of the fast fracture damage of the mechanical equipment important for the safety of nuclear islands of the French PWR relies on deterministic rules. These rules include flaw acceptance criteria involving safety factors applied to characteristic values (implicit margins) of the physical variables. The sets of safety factors that are currently under application in the industrial analyses with the agreement of the Safety Authority, are distributed across the two main physical parameters and have partly been based on a semi-probabilistic approach. After presenting the generic probabilistic pro-codification approach this paper shows its application to the evaluation of the performances of the existing regulatory flaw acceptance criteria. This application can be carried out in a realistic manner or in a more simplified one. These two approaches are applied to representative mechanical components. Their results are consistent. (author)

  8. Risk Informed Safety Margin Characterization Case Study: Selection of Electrical Equipment To Be Subjected to Environmental Qualification

    Energy Technology Data Exchange (ETDEWEB)

    D. Blanchard; R. Youngblood

    2012-04-01

    In general, the margins-based safety case helps the decision-maker manage plant margins most effectively. It tells the plant decision-maker such things as what margin is present (at the plant level, at the functional level, at the barrier level, at the component level), and where margin is thin or perhaps just degrading. If the plant is safe, it tells the decision-maker why the plant is safe and where margin needs to be maintained, and perhaps where the plant can afford to relax.

  9. Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to Account for Daily Head and Neck Pose Variations.

    Science.gov (United States)

    Stoll, Markus; Stoiber, Eva Maria; Grimm, Sarah; Debus, Jürgen; Bendl, Rolf; Giske, Kristina

    2016-01-01

    Intensity modulated radiation therapy (IMRT) of head and neck tumors allows a precise conformation of the high-dose region to clinical target volumes (CTVs) while respecting dose limits to organs a risk (OARs). Accurate patient setup reduces translational and rotational deviations between therapy planning and therapy delivery days. However, uncertainties in the shape of the CTV and OARs due to e.g. small pose variations in the highly deformable anatomy of the head and neck region can still compromise the dose conformation. Routinely applied safety margins around the CTV cause higher dose deposition in adjacent healthy tissue and should be kept as small as possible. In this work we evaluate and compare three approaches for margin generation 1) a clinically used approach with a constant isotropic 3 mm margin, 2) a previously proposed approach adopting a spatial model of the patient and 3) a newly developed approach adopting a biomechanical model of the patient. All approaches are retrospectively evaluated using a large patient cohort of over 500 fraction control CT images with heterogeneous pose changes. Automatic methods for finding landmark positions in the control CT images are combined with a patient specific biomechanical finite element model to evaluate the CTV deformation. The applied methods for deformation modeling show that the pose changes cause deformations in the target region with a mean motion magnitude of 1.80 mm. We found that the CTV size can be reduced by both variable margin approaches by 15.6% and 13.3% respectively, while maintaining the CTV coverage. With approach 3 an increase of target coverage was obtained. Variable margins increase target coverage, reduce risk to OARs and improve healthy tissue sparing at the same time.

  10. Fracture mechanics characteristics and associated safety margins for integrity assessment; Bruchmechanische Kennwerte und zugeordnete Sicherheitsfaktoren bei Integritaetsanalysen

    Energy Technology Data Exchange (ETDEWEB)

    Roos, E.; Schuler, X.; Stumpfrock, L.; Silcher, H. [Stuttgart Univ. (DE). Materialpruefungsanstalt (MPA)

    2008-07-01

    Within the integrity assessment of components and structural members of plants safety margins have to be applied, whose magnitude depend on several factors. Important factors influencing the magnitude of the safety margins are as for instance: Material behaviour (ductile / brittle behaviour), the event to be considered (local deformation / fracture), possible consequences of failure (human health, environmental damage, economic consequences) and many others. One important factor also is the fact, how precisely and reliably the appropriate material characteristics can be determined and how precisely and reliably the components behaviour can be predicted and assessed by means of this material characteristic. In contemporary safety assessment procedures by means of fracture mechanics evaluation tools (e.g. [1]) a concept of partial safety margins is proposed for application. The basic idea with this procedure is that only those sources of uncertainty have to be considered, which are relevant or may be relevant for the structure to be considered. For this purpose each source of possible uncertainty has to be quantified individually, finally only those singular safety margins are superimposed to a total safety margin which are relevant. The more the uncertainties have to be taken into account, the total safety margin to be applied, consequently will be larger. If some sources of uncertainty can be eliminated totally or can be minimized (for instance by a more reliable calculational procedure of the component loading or by more precise material characteristics), the total safety margin can be reduced. In this contribution the different procedures for the definition of safety margins within the integrity assessment by means of fracture mechanics procedures will be discussed. (orig.)

  11. An empirical assessment of driver motivation and emotional states in perceived safety margins under varied driving conditions.

    Science.gov (United States)

    Zhang, Yu; Kaber, David B

    2013-01-01

    Motivation models in driving behaviour postulate that driver motives and emotional states dictate risk tolerance under various traffic conditions. The present study used time and driver performance-based payment systems to manipulate motivation and risk-taking behaviour. Ten participants drove to a predefined location in a simulated driving environment. Traffic patterns (density and velocity) were manipulated to cause driver behaviour adjustments due to the need to conform with the social norms of the roadway. The driving environment complexity was investigated as a mediating factor in risk tolerance. Results revealed the performance-based payment system to closely relate to risk-taking behaviour as compared with the time-based payment system. Drivers conformed with social norms associated with specific traffic patterns. Higher roadway complexity led to a more conservative safety margins and speeds. This research contributes to the further development of motivational models of driver behaviour. This study provides empirical justification for two motivation factors in driver risk-taking decisions, including compliance with social norm and emotions triggered by incentives. Environment complexity was identified as a mediating factor in motivational behaviour model. This study also recommended safety margin measures sensitive to changes in driver risk tolerance.

  12. Bootstrap and Order Statistics for Quantifying Thermal-Hydraulic Code Uncertainties in the Estimation of Safety Margins

    Directory of Open Access Journals (Sweden)

    Enrico Zio

    2008-01-01

    Full Text Available In the present work, the uncertainties affecting the safety margins estimated from thermal-hydraulic code calculations are captured quantitatively by resorting to the order statistics and the bootstrap technique. The proposed framework of analysis is applied to the estimation of the safety margin, with its confidence interval, of the maximum fuel cladding temperature reached during a complete group distribution blockage scenario in a RBMK-1500 nuclear reactor.

  13. Safety margin improvement by adopting the feature of interleaving in 700 MWe PHWR

    International Nuclear Information System (INIS)

    Kumar, Nrependra; Yadav, S.K.; Khan, T.A.; Dixit, A.; Singhal, Mukesh; Nair, Suma R.

    2015-01-01

    Indian Pressurised Heavy Water Reactors (IPHWRs) of 700 MWe are under construction at Kakrapar Atomic Power Project -3,4 and Rajasthan Atomic Power Project-7,8. These units have enhanced safety features with respect to standard IPHWRs. One of the enhanced features is interleaving of feeders/channels. In interleaved feeder configuration, each header located at either end of reactor gets connected to one quarter of core channels, which are uniformly distributed. The core is divided into two loops with feeder connected in interleaved fashioned. In this paper a comparative study has been performed between the two cases: 1) The core splits in two vertical halves and each vertical half is a loop of PHT (TAPS-3 and 4 Type configuration). 2) The core is divided into two loops with feeders/ channels connected in interleaved fashioned (700 MWe Configuration). LOCA studies have been performed for 700 MWe PHWR considering interleaving of feeders configuration using in-house developed computer code ATMIKA and 3-D neutron kinetics code IQS-3D. The issue of interleaving is closely linked to an inherent reactivity characteristic of PHWR reactors (viz., positive void reactivity coefficient) which leads to a power increase following a Large LOCA. In 700 MWe PHWR with intent to improve the safety margin, adopted the feature of interleaving of feeders which causes in reduction in the magnitude of void coefficient and results in reduction of peak power during LBLOCA. The systematic LBLOCA study demonstrates that interleaved configuration of feeder/channels of two loops has higher safety margins (i.e. with respect to peak power, prompt-criticality margin, adiabatic heat deposition on the fuel pins, sheath temperature excursion and clad oxidation) with regard to the effectiveness of shutdown system. (author)

  14. Seismic Safety Margins Research Program (Phase I). Project VII. Systems analysis specification of computational approach

    International Nuclear Information System (INIS)

    Wall, I.B.; Kaul, M.K.; Post, R.I.; Tagart, S.W. Jr.; Vinson, T.J.

    1979-02-01

    An initial specification is presented of a computation approach for a probabilistic risk assessment model for use in the Seismic Safety Margin Research Program. This model encompasses the whole seismic calculational chain from seismic input through soil-structure interaction, transfer functions to the probability of component failure, integration of these failures into a system model and thereby estimate the probability of a release of radioactive material to the environment. It is intended that the primary use of this model will be in sensitivity studies to assess the potential conservatism of different modeling elements in the chain and to provide guidance on priorities for research in seismic design of nuclear power plants

  15. A generalized framework for assessment of safety margins in nuclear power plants

    International Nuclear Information System (INIS)

    Gavrilas, M.; Youngblood, B.; Prelewicz, D.; Meyer, Jim

    2004-01-01

    The protection of public health and safety, and the environment from inadvertent releases of radioactive materials from nuclear power plants relies on the implementation of the defense-in-depth strategy. The term defense-in-depth evolved historically, and thus its application has not always been uniform. The use of the term in the context of the U.S. Nuclear Regulatory Commission (NRC) safety philosophy entails the reliance of a nuclear facility on successive compensatory measures in preventing accidents or mitigating damage caused by malfunctions, accidents, or naturally occurring events. The introduction of probabilistic risk analyses with NUREG-74/014 and subsequent evolution in risk assessment techniques, are leading to the implementation of risk informed regulation to ensure the safety of the public and the environment. Risk informed regulation minimizes the likelihood of overlooking potentially significant accident sequences while limiting unnecessary burdens imposed on licensees. The proposed framework merges fundamental elements of safety regulation: defense-in depth, safety margins and probabilistic risk. It formalizes the relationship between probabilistic risk assessment (PRA) methods and data, and deterministic analyses in a manner consistent with NRC's defense-in-depth philosophy. Succinctly put, the likelihood and consequences of accident scenarios are considered simultaneously and quantified by a plant safety metric. The integration of these fundamental elements into a practically applicable safety framework is consistent with the NRC policy statement on use of probabilistic risk assessment methods and the November 2002 Regulatory Guide on risk informed decisions on plant-specific changes to the licensing basis. Safety information resulting from the application of the framework supersedes traditional safety figures of merit. Safety quantifiers, referred herein as safety indices, expand on the qualifier outcomes that currently accompany fault tree

  16. Handbook of nuclear power plant seismic fragilities, Seismic Safety Margins Research Program

    International Nuclear Information System (INIS)

    Cover, L.E.; Bohn, M.P.; Campbell, R.D.; Wesley, D.A.

    1983-12-01

    The Seismic Safety Margins Research Program (SSMRP) has a gola to develop a complete fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake-induced radioactive release from a commercial nuclear power plant. As part of this program, calculations of the seismic risk from a typical commercial nuclear reactor were made. These calculations required a knowledge of the probability of failure (fragility) of safety-related components in the reactor system which actively participate in the hypothesized accident scenarios. This report describes the development of the required fragility relations and the data sources and data reduction techniques upon which they are based. Both building and component fragilities are covered. The building fragilities are for the Zion Unit 1 reactor which was the specific plant used for development of methodology in the program. Some of the component fragilities are site-specific also, but most would be usable for other sites as well

  17. Light Water Reactor Sustainability Program Risk-Informed Safety Margins Characterization (RISMC) PathwayTechnical Program Plan

    Energy Technology Data Exchange (ETDEWEB)

    Curtis Smith; Cristian Rabiti; Richard Martineau

    2012-11-01

    Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). As the current Light Water Reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of Systems, Structures, and Components (SSCs) degradations or failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly “over-design” portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as “safety margin.” Historically, specific safety margin provisions have been formulated, primarily based on “engineering judgment.”

  18. Dose establishing a safety margin reduce local recurrence in subsegmental transarterial chemoembolization for small nodular hepatocellular carcinomas?

    International Nuclear Information System (INIS)

    Kang, Hyo Jin; Kim, Young Il; Kim, Hyo Cheol; Jae, Hwan Jun; Hur, Sae Beam; Chung, Jin Wook

    2015-01-01

    To test the hypothesis that a safety margin may affect local tumor recurrence (LTR) in subsegmental chemoembolization. In 101 patients with 128 hepatocellular carcinoma (HCC) nodules (1-3 cm in size and ≤ 3 in number), cone-beam CT-assisted subsegmental lipiodol chemoembolization was performed. Immediately thereafter, a non-contrast thin-section CT image was obtained to evaluate the presence or absence of intra-tumoral lipiodol uptake defect and safety margin. The effect of lipiodol uptake defect and safety margin on LTR was evaluated. Univariate and multivariate analyses were performed to indentify determinant factors of LTR. Of the 128 HCC nodules in 101 patients, 49 (38.3%) nodules in 40 patients showed LTR during follow-up period (median, 34.1 months). Cumulative 1- and 2-year LTR rates of nodules with lipiodol uptake defect (n = 27) and those without defect (n = 101) were 58.1% vs. 10.1% and 72.1% vs. 19.5%, respectively (p < 0.001). Among the 101 nodules without a defect, the 1- and 2-year cumulative LTR rates for nodules with complete safety margin (n = 52) and those with incomplete safety margin (n = 49) were 9.8% vs. 12.8% and 18.9% vs. 19.0% (p = 0.912). In multivariate analyses, ascites (p = 0.035), indistinct tumor margin on cone-beam CT (p = 0.039), heterogeneous lipiodol uptake (p = 0.023), and intra-tumoral lipiodol uptake defect (p < 0.001) were determinant factors of higher LTR. In lipiodol chemoembolization, the safety margin in completely lipiodolized nodule without defect will not affect LTR in small nodular HCCs

  19. Analysis of safety impacts from external flooding using the risk-informed safety margin characterization (RISMC) Toolkit

    International Nuclear Information System (INIS)

    Smith, Curtis L.; Mandelli, Diego; Prescott, Steve

    2015-01-01

    The existing fleet of U.S. nuclear power plants is in the process of extending its lifetime and increasing the power generated from these plants via power uprates. In order to evaluate the impact of these factors on the safety of the plant, the Risk-Informed Safety Margin Characterization (RISMC) project aims to provide insight to decision makers through a series of simulations of the plant dynamics for different initial conditions (e.g., probabilistic analysis and uncertainty quantification). This paper demonstrates how Idaho National Laboratory (INL) researchers use the RISMC Toolkit to investigate complex nuclear plant phenomena using RAVEN and RELAP-7. The analysis focused on a highly relevant topic currently facing some nuclear power plants – specifically flooding issues. This research and development looked at challenges to a hypothetical pressurized water reactor, including: (1) a potential loss of off-site power followed by the possible loss of all diesel generators (i.e., a station black-out event), (2) earthquake induced station-blackout, and (3) a potential earthquake induced tsunami flood. The analysis is performed by using a set of codes: a thermal-hydraulic code (RELAP-7), a flooding simulation tool (NEUTRINO) and a stochastic analysis tool (RAVEN) – these are currently under development at INL. Using RAVEN, we were able to perform multiple RELAP-7 simulation runs by changing specific parts of the model in order to reflect specific aspects of different scenarios, including both the failure and recovery of critical components. The simulation employed traditional statistical tools (such as Monte-Carlo sampling) and more advanced machine-learning based algorithms to perform uncertainty quantification in order to understand changes in system performance and limitations as a consequence of power uprate. Qualitative and quantitative results obtained gave a detailed picture of the issues associated with potential accident scenarios. These types of

  20. Major structural response methods used in the seismic safety margins research program

    International Nuclear Information System (INIS)

    Chou, C.K.; Lo, T.; Vagliente, V.

    1979-01-01

    In order to evaluate the conservatisms in present nuclear power plant seismic safety requirements, a probabilistic based systems model is being developed. This model will also be used to develop improved requirements. In Phase I of the Seismic Safety Margins Research Program (SSMRP), this methodology will be developed for a specific nuclear power plant and used to perform probabilistic sensitivity studies to gain engineering insights into seismic safety requirements. Random variables in the structural response analysis area, or parameters which cause uncertainty in the response, are discussed and classified into three categories; i.e., material properties, structural dynamic characteristics and related modeling techniques, and analytical methods. The sensitivity studies are grouped into two categories; deterministic and probabilistic. In a system analysis, transfer functions in simple form are needed since there are too many responses which have to be calculated in a Monte Carlo simulation to use the usual straightforward calculation approach. Therefore, the development of these simple transfer functions is one of the important tasks in SSMRP. Simplified as well as classical transfer functions are discussed

  1. Application of the Integrated Safety Assessment methodology to safety margins. Dynamic Event Trees, Damage Domains and Risk Assessment

    International Nuclear Information System (INIS)

    Ibánez, L.; Hortal, J.; Queral, C.; Gómez-Magán, J.; Sánchez-Perea, M.; Fernández, I.; Meléndez, E.; Expósito, A.; Izquierdo, J.M.; Gil, J.; Marrao, H.; Villalba-Jabonero, E.

    2016-01-01

    The Integrated Safety Assessment (ISA) methodology, developed by the Consejo de Seguridad Nuclear, has been applied to an analysis of Zion NPP for sequences with Loss of the Component Cooling Water System (CCWS). The ISA methodology proposal starts from the unfolding of the Dynamic Event Tree (DET). Results from this first step allow assessing the sequence delineation of standard Probabilistic Safety Analysis results. For some sequences of interest of the outlined DET, ISA then identifies the Damage Domain (DD). This is the region of uncertain times and/or parameters where a safety limit is exceeded, which indicates the occurrence of certain damage situation. This paper illustrates application of this concept obtained simulating sequences with MAAP and with TRACE. From information of simulation results of sequence transients belonging to the DD and the time-density probability distributions of the manual actions and of occurrence of stochastic phenomena, ISA integrates the dynamic reliability equations proposed to obtain the sequence contribution to the global Damage Exceedance Frequency (DEF). Reported results show a slight increase in the DEF for sequences investigated following a power uprate from 100% to 110%. This demonstrates the potential use of the method to help in the assessment of design modifications. - Highlights: • This paper illustrates an application of the ISA methodology to safety margins. • Dynamic Event Trees are useful tool for verifying the standard PSA Event Trees. • The ISA methodology takes into account the uncertainties in human action times. • The ISA methodology shows the Damage Exceedance Frequency increase in power uprates.

  2. Improving safety margins for control room habitability, through heating/ventilation/air conditioning modifications

    International Nuclear Information System (INIS)

    Beach, D.R.; Fillingim, W.; Bell, G.; Eurich, R.G.

    1989-01-01

    The Fort Calhoun power station began operation in September 1973. Since that time, modifications to the plant have required the addition of a substantial number of electrical and control components in the control room, which has resulted in an increased heat load in this area. Additionally, NUREG-0737, Item III.D.3.4, imposed requirements on the ventilating system related to protection of personnel from the effects of toxic and radioactive gas releases, which were not considered in the original design. Omaha Public Power District (OPPD) has recently undertaken a major modification to the Fort Calhoun station control room ventilating system to improve the safety margins for control room habitability. The goals of the modification were to achieve adequate cooling capacity with fully redundant equipment, improve habitability under accident conditions, and eliminate several potential problems related to steam line break and equipment qualification. Additionally, the scope of the project grew as design problems emerged

  3. Methodology for the Assessment of Confidence in Safety Margin for Small Break Loss of Coolant Accident Sequences

    Energy Technology Data Exchange (ETDEWEB)

    Nagrale, D. B.; Prasad, M.; Rao, R. S.; Gaikwad, A.J., E-mail: avinashg@aerb.gov.in [Nuclear Safety Analysis Division, Atomic Energy Regulatory Board, Mumbai (India)

    2014-10-15

    Deterministic Safety Analysis and Probabilistic Safety Assessment (PSA) analyses are used concurrently to assess the Nuclear Power Plant (NPP) safety. The conventional deterministic analysis is conservative. The best estimate plus uncertainty analysis is increasingly being used for deterministic calculation in NPPs. The PSA methodology aims to be as realistic as possible while integrating information about accident phenomena, plant design, operating practices, component reliability and human behaviour. The peak clad temperature (PCT) distribution provides an insight into the confidence in safety margin for an initiating event. The paper deals with the concept of calculating the peak clad temperature with 95 percent confidence and 95 percent probability (PCT{sub 95/95}) in small break loss of coolant accident (SBLOCA) and methodologies for assessing safety margin. Five input parameters mainly, nominal power level, decay power, fuel clad gap conductivity, fuel thermal conductivity and discharge coefficient, were selected. A Uniform probability density function was assigned to the uncertain parameters and these uncertainties are propagated using Latin Hypercube Sampling (LHS) technique. The sampled data for 5 parameters were randomly mixed by LHS to obtain 25 input sets. A non-core damage accident sequence was selected from the SBLOCA event tree of a typical VVER study to estimate the PCTs and safety margin. A Kolmogorov– Smirnov goodness-of-fit test was carried out for PCTs. The smallest value of safety margin would indicate the robustness of the system with 95% confidence and 95% probability. Regression analysis was also carried out using 1000 sample size for the estimating PCTs. Mean, variance and finally safety margin were analysed. (author)

  4. Determination of safety margins for whole blood concentrations of alcohol and nineteen drugs in driving under the influence cases.

    Science.gov (United States)

    Kristoffersen, Lena; Strand, Dag Helge; Liane, Veronica Horpestad; Vindenes, Vigdis; Tvete, Ingunn Fride; Aldrin, Magne

    2016-02-01

    Legislative limits for driving under the influence of 20 non-alcohol drugs were introduced in Norway in February 2012. Per se limits corresponding to blood alcohol concentrations (BAC) of 0.2g/kg were established for 20 psychoactive drugs, and limits for graded sanctions corresponding to BACs of 0.5 and 1.2g/kg were determined for 13 of these drugs. This new legislation made it possible for the courts to make sentences based on the analytical results, similar to the situation for alcohol. To ensure that the reported concentration is as least as high as the true concentration, with a 99% safety level, safety margins had to be calculated for each of the substances. Diazepam, tetrahydrocannabinol (THC) and alcohol were used as model substances to establish a new model for estimating the safety margins. The model was compared with a previous used model established several years ago, by a similar yet much simpler model, and they were found to be in agreement. The measurement uncertainties depend on the standard batch used, the work list and the measurements' replicate. A Bayesian modelling approach was used to determine the parameters in the model, using a dataset of 4700 diazepam positive specimens and 5400 THC positive specimens. Different safety margins were considered for low and high concentration levels of diazepam (≤2μM (0.6mg/L) and >2μM) and THC (≤0.01μM (0.003mg/L) and >0.01μM). The safety margins were for diazepam 19.5% (≤2μM) and 34% (>2μM), for THC 19.5% (≤0.01μM) and 24.9% (>0.01μM). Concentration dependent safety margins for BAC were based on a dataset of 29500 alcohol positive specimens, and were in the range 10.4% (0.1g/kg) to 4.0% (4.0g/kg) at a 99% safety level. A simplified approach was used to establish safety margins for the compounds amphetamine, MDMA, methamphetamine, alprazolam, phenazepam, flunitrazepam, clonazepam, nitrazepam, oxazepam, buprenorphine, GHB, methadone, ketamine, cocaine, morphine, zolpidem and zopiclone. The

  5. Hydraulic safety margins and embolism reversal in stems and leaves: Why are conifers and angiosperms so different?

    Science.gov (United States)

    Daniel M. Johnson; Katherine A. McCulloh; David R. Woodruff; Frederick C. Meinzer

    2012-01-01

    Angiosperm and coniferous tree species utilize a continuum of hydraulic strategies. Hydraulic safety margins (defined as differences between naturally occurring xylem pressures and pressures that would cause hydraulic dysfunction, or differences between pressures resulting in loss of hydraulic function in adjacent organs (e.g., stems vs. leaves) tend to be much greater...

  6. Safety margin evaluation of pre-stressed concrete nuclear containment vessel model with BARC code ULCA

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  7. Continuous Assessment of Safety Margin for the 14-MW TRIGA Reactor

    International Nuclear Information System (INIS)

    Ciocanescu, M.; Georgescu, D.; Doru, O.

    2008-01-01

    The assessment of reactor safety implies analyses of the reactor and its systems response to a range of postulated initiating events (such as malfunction or failures of equipment, operator errors, external events and so on which could lead to either anticipated operational occurrences or to accident conditions. Decreasing in heat removal by the reactor cooling system may be considered as a process disturbance which may lead to a postulated initiating event. The cold source for the reactor cooling system, in case of TRIGA-14 MW reactor is the atmosphere by the secondary cooling towers. The ability to evacuate the heat produced by the reactor core ranges between the outlet temperature of the core flow and the outdoors temperature in air, which is subject to season and day variation. Selected values for safety limits, safety system settings and limiting condition(s) are derived from safety analysis and are consistent with the operational state of the reactor. When a limiting condition for safe operation is not satisfied, the operating personal is supposed to take the appropriate action(s) to ensure safety. Operating requirements and the safety system are presented. The reactor operating safety parameters from the main Data Acquisition System are transferred to an AT personal computer. These selected parameters are the following: - average inlet temperature which is calculated as an average temperature measured by 20 type K thermocouples distributed within a 4 x 5 matrix located on the top of the reactor core; - average outlet temperature which is calculated as an average record from 10 type K thermocouples placed in the outlet pipe; - average flow rate which is calculated as an average value from four transducers (two for the inlet flow rate and two for the outlet flow rate). Due to its high instability, this value is also filtered using a two-pole low-pass filter (software); - reactor thermal power value derivable from the previous parameters or obtained from the

  8. Single-Coil Defibrillator Leads Yield Satisfactory Defibrillation Safety Margin in Hypertrophic Cardiomyopathy.

    Science.gov (United States)

    Okamura, Hideo; Friedman, Paul A; Inoue, Yuko; Noda, Takashi; Aiba, Takeshi; Yasuda, Satoshi; Ogawa, Hisao; Kamakura, Shiro; Kusano, Kengo; Espinosa, Raul E

    2016-09-23

    Single-coil defibrillator leads have gained favor because of their potential ease of extraction. However, a high defibrillation threshold remains a concern in patients with hypertrophic cardiomyopathy (HCM), and in many cases, dual-coil leads have been used for this patient group. There is little data on using single-coil leads for HCM patients. We evaluated 20 patients with HCM who received an implantable cardioverter-defibrillator (ICD) on the left side in combination with a dual-coil lead. Two sets of defibrillation tests were performed in each patient, one with the superior vena cava (SVC) coil "on" and one with the SVC coil "off". ICDs were programmed to deliver 25 joules (J) for the first attempt followed by maximum energy (35 J or 40 J). Shock impedance and shock pulse width at 25 J in each setting as well as the results of the shock were analyzed. All 25-J shocks in both settings successfully terminated ventricular fibrillation. However, shock impedance and pulse width increased substantially with the SVC coil programmed "off" compared with "on" (66.4±6.1 ohm and 14.0±1.3 ms "off" vs. 41.9±5.0 ohm and 9.3±0.8 ms "on", Psatisfactory safety margin for 35-J devices. Single-coil leads appear appropriate for left-sided implantation in this patient group. (Circ J 2016; 80: 2199-2203).

  9. Seismic Safety Margins Research Program: Phase II program plan (FY 83-FY 84)

    International Nuclear Information System (INIS)

    Bohn, M.P.; Bernreuter, D.L.; Cover, L.E.; Johnson, J.J.; Shieh, L.C.; Shukla, S.N.; Wells, J.E.

    1982-01-01

    The Seismic Safety Margins Research Program (SSMRP) is an NRC-funded, multiyear program conducted by Lawrence Livermore National Laboratory (LLNL). Its goal is to develop a complete, fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake-caused radioactive release from a commercial nuclear power plant. The analysis procedure is based upon a state-of-the-art evaluation of the current seismic analysis and design process and explicitly includes the uncertainties inherent in such a process. The results will be used to improve seismic licensing requirements for nuclear power plants. As currently planned, the SSMRP will be completed in September, 1984. This document presents the program plan for work to be done during the remainder of the program. In Phase I of the SSMRP, the necessary tools (both computer codes and data bases) for performing a detailed seismic risk analysis were identified and developed. Demonstration calculations were performed on the Zion Nuclear Power Plant. In the remainder of the program (Phase II) work will be concentrated on developing a simplified SSMRP methodology for routine probabilistic risk assessments, quantitative validation of the tools developed and application of the simplified methodology to a Boiling Water Reactor. (The Zion plant is a pressurized water reactor.) In addition, considerable effort will be devoted to making the codes and data bases easily accessible to the public

  10. Comparison of safety margins for leak-before-break assessment of 500 MWe PHWR straight pipes: using contemporary techniques

    International Nuclear Information System (INIS)

    Rastogi, Rohit; Bhasin, Vivek; Kushwaha, H.S.

    1998-01-01

    The Leak Before Break (LBB) analysis of Primary Heat Transport (PHT) Piping of 500 MWe Indian PHWR is being performed using different well established techniques like R6 method (Nuclear Electric UK) and J-Tearing based methods (USNRC). These methods show that PHT piping has required safety margins and can be qualified for LBB. These analysis also showed that the piping has high fracture toughness and plastic collapse is the dominant mode of failure. To enhance the confidence in the results obtained from the above methods, further studies were done on the PHT piping. Procedures which predicted margins against plastic collapse were used. The analysis procedures used were Modified Limit Load Method, MPA Method (both from Germany), Moments Method (from Italy) and the Z-Factor method given in ASME Boiler and Pressure Vessel Code. The safety margins obtained from these analysis satisfied the LBB requirements. A table was generated which compared the safety margins obtained using all the above mentioned procedures. This report presents the results of this study. (author)

  11. A new assessment method for demonstrating the sufficiency of the safety assessment and the safety margins of the geological disposal system

    International Nuclear Information System (INIS)

    Ohi, Takao; Kawasaki, Daisuke; Chiba, Tamotsu; Takase, Toshio; Hane, Koji

    2013-01-01

    A new method for demonstrating the sufficiency of the safety assessment and safety margins of the geological disposal system has been developed. The method is based on an existing comprehensive sensitivity analysis method and can systematically identify the successful conditions, under which the dose rate does not exceed specified safety criteria, using analytical solutions for nuclide migration and the results of a statistical analysis. The successful conditions were identified using three major variables. Furthermore, the successful conditions at the level of factors or parameters were obtained using relational equations between the variables and the factors or parameters making up these variables. In this study, the method was applied to the safety assessment of the geological disposal of transuranic waste in Japan. Based on the system response characteristics obtained from analytical solutions and on the successful conditions, the classification of the analytical conditions, the sufficiency of the safety assessment and the safety margins of the disposal system were then demonstrated. A new assessment procedure incorporating this method into the existing safety assessment approach is proposed in this study. Using this procedure, it is possible to conduct a series of safety assessment activities in a logical manner. (author)

  12. Light Water Reactor Sustainability Program Technical Basis Guide Describing How to Perform Safety Margin Configuration Risk Management

    Energy Technology Data Exchange (ETDEWEB)

    Curtis Smith; James Knudsen; Bentley Harwood

    2013-08-01

    The INL has carried out a demonstration of the RISMC approach for the purpose of configuration risk management. We have shown how improved accuracy and realism can be achieved by simulating changes in risk – as a function of different configurations – in order to determine safety margins as the plant is modified. We described the various technical issues that play a role in these configuration-based calculations with the intent that future applications can take advantage of the analysis benefits while avoiding some of the technical pitfalls that are found for these types of calculations. Specific recommendations have been provided on a variety of topics aimed at improving the safety margin analysis and strengthening the technical basis behind the analysis process.

  13. History of aviation safety; the satisfying sighs of relief due to developments in Aviation safety

    NARCIS (Netherlands)

    Stoop, J.A.A.M.

    2014-01-01

    ”Aviation safety is an Integral part of my career. Being part of TU Delft’s impressive record of research on Aviation safety, my career has been with a sense of purpose and a responsibility to equip students to deal with the status quo challenges on Aviation safety, developments, Investigations and

  14. Seismic safety margins research program. Phase I final report - Major structure response (Project IV)

    International Nuclear Information System (INIS)

    Benda, B.J.; Johnson, J.J.; Lo, T.Y.

    1981-08-01

    The primary task of the Major Structure Response Project within the Seismic Safety Margins Research Program (SSMRP) was to develop detailed finite element models of the Zion Nuclear Power Plant's containment building and auxiliary-fuel-turbine (AFT) complex. The resulting models served as input to the seismic methodology analysis chain. The containment shell was modeled as a series of beam elements with the shear and bending characteristics of a circular cylindrical shell. Masses and rotary inertias were lumped at nodal points; thirteen modes were included in the analysis. The internal structure was modeled with three-dimensional finite elements, with masses again lumped at selected nodes; sixty modes were included in the analysis. The model of the AFT complex employed thin plate and shell elements to represent the concrete shear walls and floor diaphragms, and beam and truss elements to model the braced frames. Because of the size and complexity of the model, and the potentially large number of degrees of freedom, masses were lumped at a limited number of node points. These points were selected so as to minimize the effect of the discrete mass distribution on structural response. One hundred and thirteen modes were extracted. A second objective of Project IV was to investigate the effects of uncertainty and variability on structural response. To this end, four side studies were conducted. Three of them, briefly summarized in this volume, addressed themselves respectively to an investigation of sources of random variability in the dynamic response of nuclear power plant structures; formulation of a methodology for modeling and evaluating the effects of structural uncertainty on predicted modal characteristics of major nuclear power plant structures and substructures; and a preliminary evaluation of nonlinear responses in shear-wall structures. A fourth side study, reported in detail in this volume, quantified variations in dynamic characteristics and seismic

  15. On the functional failures concept and probabilistic safety margins: challenges in application for evaluation of effectiveness of shutdown systems - 15318

    International Nuclear Information System (INIS)

    Serghiuta, D.; Tholammakkil, J.

    2015-01-01

    The use of level-3 reliability approach and the concept of functional failure probability could provide the basis for defining a safety margin metric which would include a limit for the probability of functional failure, in line with the definition of a reliability-based design. It can also allow a quantification of level of confidence, by explicit modeling and quantification of uncertainties, and provide a better framework for representation of actual design and optimization of design margins within an integrated probabilistic-deterministic model. This paper reviews the attributes and challenges in application of functional failure concept in evaluation of risk-informed safety margins using as illustrative example the case of CANDU reactors shutdown systems effectiveness. A risk-informed formulation is first introduced for estimation of a reasonable limit for the functional failure probability using a Swiss cheese model. It is concluded that more research is needed in this area and a deterministic - probabilistic approach may be a reasonable intermediate step for evaluation of functional failure probability at the system level. The views expressed in this paper are those of the authors and do not necessarily reflect those of CNSC, or any part thereof. (authors)

  16. Verification of Safety Margins of Battery Banks Capacity of Class 1E DC System in a Nuclear Power Plant

    International Nuclear Information System (INIS)

    Lukman, Abdulrauf; Zhu, Oon-Pyo

    2015-01-01

    According to Ref 'Station blackout (SBO) is generally a plant condition with complete loss of all alternating current (AC) power from off-site sources, from the main generator and from standby AC power sources important to safety to the essential and nonessential switchgear buses. Direct current (DC) power supplies and uninterruptible AC power supplies may be available as long as batteries can supply the loads, alternate AC power supplies are available'. The above IAEA document indicated the importance of batteries during SBO. Prior to the Fukushima accident, most batteries might be designed with coping capability of four hours. However, the accident showed the need for the coping capability to be increased to at least eight hours. The purpose of this research is to verify the safety capacity margin of the nuclear qualified battery banks of class 1E DC system and test the response to SBO using the load profile of a Korean design nuclear power plant (NPP). The capacity margins of class 1E batteries of DC power system batteries in a nuclear power plant were determined using the load profile of the plant. It was observed that if appropriate manufacturer Kt data are not available, the accuracy of the battery capacity might not be accurately calculated. The result obtained shows that the batteries have the coping capability of two hours for channel A and B, and eight hours for channel C and D. Also capacity margin as show in figure show a reasonable margin for each batteries of the DC system

  17. Potential improvement of CANDU NPP safety margins by shortening the response time of shutdown systems using FPGA based implementation

    Energy Technology Data Exchange (ETDEWEB)

    Jingke She, E-mail: jshe2@uwo.ca [Department of Electrical and Computer Engineering, University of Western Ontario, London, Ontario N6A 5B9 (Canada); Jin Jiang, E-mail: jjiang@eng.uwo.ca [Department of Electrical and Computer Engineering, University of Western Ontario, London, Ontario N6A 5B9 (Canada)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Quantitative analysis of the safety margin improvement through thermalhydraulic simulation and analysis. Black-Right-Pointing-Pointer Hardware-in-the-loop simulation of realizing the improvement by an FPGA-based SDS1. Black-Right-Pointing-Pointer Verification of potential operating power upgrade without endangering the plant safety. - Abstract: The relationship between the peak values of critical reactor variables, such as neutronic power, inside a CANDU reactor and the speed of the response of its shutdown system has been analyzed in the event of a large loss of coolant accident (LOCA). The advantage of shortening the response time of the shutdown action has been demonstrated in term of the improved safety margin. A field programmable gate array (FPGA) platform has been chosen to implement such a shutdown system. Hardware-in-the-loop (HIL) simulations have been performed to demonstrate the feasibility of this concept. Furthermore, connections between the speed of response of the shutdown system and the nominal operating power level of the reactor have been drawn to support for potential power upgrade for existing power plants.

  18. A practical due diligence strategy for managing the safety of contractors

    International Nuclear Information System (INIS)

    Catton, C.

    1998-01-01

    Ontario Hydro's Fossil Business has developed and implemented a practical program to ensure that the due diligence requirements for contractors are met, particularly in the health and safety area. Companies in the power generation business are hiring contractors to protect their competitive potential by having them perform specialty work outside the core business of generating electricity. The reasons behind this trend, and the need for companies to develop comprehensive contractor safety management systems to avoid legislative liability and cost overruns, and to have contractors work safely, are examined. The main elements of Ontario Hydro's Fossil Business Contractor Safety Management Program (contractor safety policy, contractor safety manual, contractor safety training, and a contractor safety performance database) are discussed. 2 figs., 2 appendices

  19. SSI sensitivity studies and model improvements for the US NRC Seismic Safety Margins Research Program. Rev. 1

    International Nuclear Information System (INIS)

    Johnson, J.J.; Maslenikov, O.R.; Benda, B.J.

    1984-10-01

    The Seismic Safety Margins Research Program (SSMRP) is a US NRC-funded program conducted by Lawrence Livermore National Laboratory. Its goal is to develop a complete fully coupled analysis procedure for estimating the risk of an earthquake-induced radioactive release from a commercial nuclear power plant. In Phase II of the SSMRP, the methodology was applied to the Zion nuclear power plant. Three topics in the SSI analysis of Zion were investigated and reported here - flexible foundation modeling, structure-to-structure interaction, and basemat uplift. The results of these investigations were incorporated in the SSMRP seismic risk analysis. 14 references, 51 figures, 13 tables

  20. Differences in safety margins between nuclear and conventional design standards with regards to seismic hazard definition and design criteria

    International Nuclear Information System (INIS)

    Elgohary, M.; Saudy, A.; Orbovic, N.; Dejan, D.

    2006-01-01

    With the surging interest in new build nuclear all over the world and a permanent interest in earthquake resistance of nuclear plants, there is a need to quantify the safety margins in nuclear buildings design in comparison to conventional buildings in order to increase the public confidence in the safety of nuclear power plants. Nuclear (CAN3-N289 series) and conventional (NBCC 2005) seismic standards have different approaches regarding the design of civil structures. The origin of the differences lays in the safety philosophy behind the seismic nuclear and conventional standards. Conventional seismic codes contain the minimal requirement destined primarily to safeguard against major structural failure and loss of life. It doesn't limit damage to a certain acceptable degree or maintain function. Nuclear seismic code requires that structures, systems and components important to safety, withstand the effects of earthquakes. The requirement states that for equipment important to safety, both integrity and functionality should be ascertained. The seismic hazard is generally defined on the basis of the annual probability of exceedence (return period). There is a major difference on the return period and the confidence level for design earthquakes between the conventional and the nuclear seismic standards. The seismic design criteria of conventional structures are based on the use of Force Modification Factors to take into account the energy dissipation by incursion in non-elastic domain and the reserve of strength. The use of such factors to lower intentionally the seismic input is consistent with the safety philosophy of the conventional seismic standard which is the 'non collapse' rather than the integrity and/or the operability of the structures or components. Nuclear seismic standard requires that the structure remain in the elastic domain; energy dissipation by incursion in non-elastic domain is not allowed for design basis earthquake conditions. This is

  1. Robust Adaptation? Assessing the sensitivity of safety margins in flood defences to uncertainty in future simulations - a case study from Ireland.

    Science.gov (United States)

    Murphy, Conor; Bastola, Satish; Sweeney, John

    2013-04-01

    Climate change impact and adaptation assessments have traditionally adopted a 'top-down' scenario based approach, where information from different Global Climate Models (GCMs) and emission scenarios are employed to develop impacts led adaptation strategies. Due to the tradeoffs in the computational cost and need to include a wide range of GCMs for fuller characterization of uncertainties, scenarios are better used for sensitivity testing and adaptation options appraisal. One common approach to adaptation that has been defined as robust is the use of safety margins. In this work the sensitivity of safety margins that have been adopted by the agency responsible for flood risk management in Ireland, to the uncertainty in future projections are examined. The sensitivity of fluvial flood risk to climate change is assessed for four Irish catchments using a large number of GCMs (17) forced with three emissions scenarios (SRES A1B, A2, B1) as input to four hydrological models. Both uncertainty within and between hydrological models is assessed using the GLUE framework. Regionalisation is achieved using a change factor method to infer changes in the parameters of a weather generator using monthly output from the GCMs, while flood frequency analysis is conducted using the method of probability weighted moments to fit the Generalised Extreme Value distribution to ~20,000 annual maxima series. The sensitivity of design margins to the uncertainty space considered is visualised using risk response surfaces. The hydrological sensitivity is measured as the percentage change in flood peak for specified recurrence intervals. Results indicate that there is a considerable residual risk associated with allowances of +20% when uncertainties are accounted for and that the risk of exceedence of design allowances is greatest for more extreme, low frequency events with considerable implication for critical infrastructure, e.g., culverts, bridges, flood defences whose designs are normally

  2. Seismic Safety Margins Research Program. Phase 1. Project V. Structural sub-system response: subsystem response review

    International Nuclear Information System (INIS)

    Fogelquist, J.; Kaul, M.K.; Koppe, R.; Tagart, S.W. Jr.; Thailer, H.; Uffer, R.

    1980-03-01

    This project is directed toward a portion of the Seismic Safety Margins Research Program which includes one link in the seismic methodology chain. The link addressed here is the structural subsystem dynamic response which consists of those components and systems whose behavior is often determined decoupled from the major structural response. Typically the mathematical model utilized for the major structural response will include only the mass effects of the subsystem and the main model is used to produce the support motion inputs for subsystem seismic qualification. The main questions addressed in this report have to do with the seismic response uncertainty of safety-related components or equipment whose seismic qualification is performed by (a) analysis, (b) tests, or (c) combinations of analysis and tests, and where the seismic input is assumed to have no uncertainty

  3. Average years of life lost due to breast and cervical cancer and the association with the marginalization index in Mexico in 2000 and 2010

    Directory of Open Access Journals (Sweden)

    Claudio Alberto Dávila Cervantes

    2014-05-01

    Full Text Available The objective of this study was to calculate average years of life lost due to breast and cervical cancer in Mexico in 2000 and 2010. Data on mortality in women aged between 20 and 84 years was obtained from the National Institute for Statistics and Geography. Age-specific mortality rates and average years of life lost, which is an estimate of the number of years that a person would have lived if he or she had not died prematurely, were estimated for both diseases. Data was disaggregated into five-year age groups and socioeconomic status based on the 2010 marginalization index obtained from the National Population Council. A decrease in average years of life lost due to cervical cancer (37.4% and an increase in average years of life lost due breast cancer (8.9% was observed during the period studied. Average years of life lost due to cervical cancer was greater among women living in areas with a high marginalization index, while average years of life lost due to breast cancer was greater in women from areas with a low marginalization index.

  4. Average years of life lost due to breast and cervical cancer and the association with the marginalization index in Mexico in 2000 and 2010.

    Science.gov (United States)

    Cervantes, Claudio Alberto Dávila; Botero, Marcela Agudelo

    2014-05-01

    The objective of this study was to calculate average years of life lost due to breast and cervical cancer in Mexico in 2000 and 2010. Data on mortality in women aged between 20 and 84 years was obtained from the National Institute for Statistics and Geography. Age-specific mortality rates and average years of life lost, which is an estimate of the number of years that a person would have lived if he or she had not died prematurely, were estimated for both diseases. Data was disaggregated into five-year age groups and socioeconomic status based on the 2010 marginalization index obtained from the National Population Council. A decrease in average years of life lost due to cervical cancer (37.4%) and an increase in average years of life lost due breast cancer (8.9%) was observed during the period studied. Average years of life lost due to cervical cancer was greater among women living in areas with a high marginalization index, while average years of life lost due to breast cancer was greater in women from areas with a low marginalization index.

  5. Quantification and Assessment of Interfraction Setup Errors Based on Cone Beam CT and Determination of Safety Margins for Radiotherapy.

    Directory of Open Access Journals (Sweden)

    Macarena Cubillos Mesías

    Full Text Available To quantify interfraction patient setup-errors for radiotherapy based on cone-beam computed tomography and suggest safety margins accordingly.Positioning vectors of pre-treatment cone-beam computed tomography for different treatment sites were collected (n = 9504. For each patient group the total average and standard deviation were calculated and the overall mean, systematic and random errors as well as safety margins were determined.The systematic (and random errors in the superior-inferior, left-right and anterior-posterior directions were: for prostate, 2.5(3.0, 2.6(3.9 and 2.9(3.9mm; for prostate bed, 1.7(2.0, 2.2(3.6 and 2.6(3.1mm; for cervix, 2.8(3.4, 2.3(4.6 and 3.2(3.9mm; for rectum, 1.6(3.1, 2.1(2.9 and 2.5(3.8mm; for anal, 1.7(3.7, 2.1(5.1 and 2.5(4.8mm; for head and neck, 1.9(2.3, 1.4(2.0 and 1.7(2.2mm; for brain, 1.0(1.5, 1.1(1.4 and 1.0(1.1mm; and for mediastinum, 3.3(4.6, 2.6(3.7 and 3.5(4.0mm. The CTV-to-PTV margins had the smallest value for brain (3.6, 3.7 and 3.3mm and the largest for mediastinum (11.5, 9.1 and 11.6mm. For pelvic treatments the means (and standard deviations were 7.3 (1.6, 8.5 (0.8 and 9.6 (0.8mm.Systematic and random setup-errors were smaller than 5mm. The largest errors were found for organs with higher motion probability. The suggested safety margins were comparable to published values in previous but often smaller studies.

  6. Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastases

    Directory of Open Access Journals (Sweden)

    Seidensticker Max

    2010-03-01

    Full Text Available Abstract Backround Micrometastases of colorectal liver metastases are present in up to 50% of lesions. In this study we sought to determine the threshold dose for local control of occult micrometastases in patients undergoing CT (computed tomography-guided brachytherapy of colorectal liver metastases. Materials and methods Nineteen patients demonstrated 34 local tumor recurrences originating from micrometastases after CT-guided brachytherapy of 27 colorectal liver metastases. We considered a local tumor recurrence as originating from a micrometastasis if tumor regrowth occurred adjacent to a formerly irradiated lesion and the distance of the 3D isocenter of the new lesion was ≤ 23.5 mm from the previous tumor margin. Follow-up MRI was fused with the planning-CT and dosimetry data. Two reviewers independently indicated the dose exposure at the isocenter of the micrometastases. Statistical analysis included an analysis of variance (ANOVA using backward selection. 95% tolerance intervals with coverage of 87.5 and 75% of the data of the normal distribution were calculated. Results The median distance of the micrometastases to the margin of the originating colorectal metastases was 8.75 mm (1-21 mm. Dose exposure at the isocenter was 12.25 Gy (7-19.8 in median. We stratified according to the distance from the isocenter to the initial tumor margin: ≤ 9 mm, > 9-15 mm and > 15 mm. The median dose in the according isocenters was 13.18, 11.6 and 11.85 Gy. The threshold dose failing to prevent micrometastasis growth was sigificantly higher in a subgroup of lesions with ≤ 9 mm distance as compared to > 15 mm (13.18 vs 11.85 Gy. Adjuvant chemotherapy correlated with greater distance of micrometastasis growth to the tumor but not with the threshold dose. Conclusion To prevent loss of local tumor control by continuous growth of micrometastases a threshold dose of 15,4 Gy (single fraction should be delivered at a distance of 21 mm to the gross tumor

  7. Implicit Treatment of Technical Specification and Thermal Hydraulic Parameter Uncertainties in Gaussian Process Model to Estimate Safety Margin

    Directory of Open Access Journals (Sweden)

    Douglas A. Fynan

    2016-06-01

    Full Text Available The Gaussian process model (GPM is a flexible surrogate model that can be used for nonparametric regression for multivariate problems. A unique feature of the GPM is that a prediction variance is automatically provided with the regression function. In this paper, we estimate the safety margin of a nuclear power plant by performing regression on the output of best-estimate simulations of a large-break loss-of-coolant accident with sampling of safety system configuration, sequence timing, technical specifications, and thermal hydraulic parameter uncertainties. The key aspect of our approach is that the GPM regression is only performed on the dominant input variables, the safety injection flow rate and the delay time for AC powered pumps to start representing sequence timing uncertainty, providing a predictive model for the peak clad temperature during a reflood phase. Other uncertainties are interpreted as contributors to the measurement noise of the code output and are implicitly treated in the GPM in the noise variance term, providing local uncertainty bounds for the peak clad temperature. We discuss the applicability of the foregoing method to reduce the use of conservative assumptions in best estimate plus uncertainty (BEPU and Level 1 probabilistic safety assessment (PSA success criteria definitions while dealing with a large number of uncertainties.

  8. Two-stream cyclotron radiative instabilities due to the marginally mirror-trapped fraction for fustion alphas in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Arunasalam, V.

    1995-07-01

    It is shown here that the marginally mirror-trapped fraction of the newly-born fusion alpha particles in the deuterium-tritium (DT) reaction dominated tokamak plasmas can induce a two-stream cyclotron radiative instability for the fast Alfven waves propagating near the harmonics of the alpha particle cyclotron frequency {omega}{sub c{alpha}}. This can explain both the experimentally observed time behavior and the spatially localized origin of the fusion product ion cyclotron emission (ICE) in TFTR at frequencies {omega} {approx} m{omega}{sub c{alpha}}.

  9. Two-stream cyclotron radiative instabilities due to the marginally mirror-trapped fraction for fustion alphas in tokamaks

    International Nuclear Information System (INIS)

    Arunasalam, V.

    1995-07-01

    It is shown here that the marginally mirror-trapped fraction of the newly-born fusion alpha particles in the deuterium-tritium (DT) reaction dominated tokamak plasmas can induce a two-stream cyclotron radiative instability for the fast Alfven waves propagating near the harmonics of the alpha particle cyclotron frequency ω cα . This can explain both the experimentally observed time behavior and the spatially localized origin of the fusion product ion cyclotron emission (ICE) in TFTR at frequencies ω ∼ mω cα

  10. Vertiefungskurs 2014. Safety margins in nuclear power plants. Identify, quantify and extend; Vertiefungskurs 2014 zum Thema ''Sicherheitsmargen in Kernkraftwerken. Identifizieren, quantifizieren, erweitern''

    Energy Technology Data Exchange (ETDEWEB)

    Rey, Matthias

    2015-02-15

    Fifteen speakers dealt with the topic safety margins in nuclear power plants from different points of view at the ''Vertiefungskurs 2014'' of the Nuklearforum Schweiz in Olten, 4 and 5 November 2014. In the context of the ''Vertiefungskurs 2014'' the safety margins in power plants were considered and quantified and possible extensions have been discussed. The conference started with an in-depth introduction of the basis design of existing nuclear power plants. Thereafter speakers told about the main topics emergency preparedness, knowledge management and safety retrofit of nuclear power plants in operation.

  11. Data Analysis Approaches for the Risk-Informed Safety Margins Characterization Toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Mandelli, Diego [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alfonsi, Andrea [Idaho National Lab. (INL), Idaho Falls, ID (United States); Maljovec, Daniel P. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Parisi, Carlo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cogliati, Joshua J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Talbot, Paul W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smith, Curtis L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Picoco, Claudia [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    In the past decades, several numerical simulation codes have been employed to simulate accident dynamics (e.g., RELAP5-3D, RELAP-7, MELCOR, MAAP). In order to evaluate the impact of uncertainties into accident dynamics, several stochastic methodologies have been coupled with these codes. These stochastic methods range from classical Monte-Carlo and Latin Hypercube sampling to stochastic polynomial methods. Similar approaches have been introduced into the risk and safety community where stochastic methods (such as RAVEN, ADAPT, MCDET, ADS) have been coupled with safety analysis codes in order to evaluate the safety impact of timing and sequencing of events. These approaches are usually called Dynamic PRA or simulation-based PRA methods. These uncertainties and safety methods usually generate a large number of simulation runs (database storage may be on the order of gigabytes or higher). The scope of this paper is to present a broad overview of methods and algorithms that can be used to analyze and extract information from large data sets containing time dependent data. In this context, “extracting information” means constructing input-output correlations, finding commonalities, and identifying outliers. Some of the algorithms presented here have been developed or are under development within the RAVEN statistical framework.

  12. Data Analysis Approaches for the Risk-Informed Safety Margins Characterization Toolkit

    International Nuclear Information System (INIS)

    Mandelli, Diego; Alfonsi, Andrea; Maljovec, Daniel P.; Parisi, Carlo; Cogliati, Joshua J.; Talbot, Paul W.; Smith, Curtis L.; Rabiti, Cristian; Picoco, Claudia

    2016-01-01

    In the past decades, several numerical simulation codes have been employed to simulate accident dynamics (e.g., RELAP5-3D, RELAP-7, MELCOR, MAAP). In order to evaluate the impact of uncertainties into accident dynamics, several stochastic methodologies have been coupled with these codes. These stochastic methods range from classical Monte-Carlo and Latin Hypercube sampling to stochastic polynomial methods. Similar approaches have been introduced into the risk and safety community where stochastic methods (such as RAVEN, ADAPT, MCDET, ADS) have been coupled with safety analysis codes in order to evaluate the safety impact of timing and sequencing of events. These approaches are usually called Dynamic PRA or simulation-based PRA methods. These uncertainties and safety methods usually generate a large number of simulation runs (database storage may be on the order of gigabytes or higher). The scope of this paper is to present a broad overview of methods and algorithms that can be used to analyze and extract information from large data sets containing time dependent data. In this context, ''extracting information'' means constructing input-output correlations, finding commonalities, and identifying outliers. Some of the algorithms presented here have been developed or are under development within the RAVEN statistical framework.

  13. Gross margin losses due to Salmonella Dublin infection in Danish dairy cattle herds estimated by simulation modelling

    DEFF Research Database (Denmark)

    Nielsen, Torben Dahl; Kudahl, Anne Braad; Østergaard, S.

    2013-01-01

    and dynamic simulation model. The model incorporated six age groups (neonatal, pre-weaned calves, weaned calves, growing heifers, breeding heifers and cows) and five infection stages (susceptible, acutely infected, carrier, super shedder and resistant). The effects of introducing one S. Dublin infectious......Salmonella Dublin affects production and animal health in cattle herds. The objective of this study was to quantify the gross margin (GM) losses following introduction and spread of S. Dublin within dairy herds. The GM losses were estimated using an age-structured stochastic, mechanistic...... with poorer management and herd size, e.g. average annual GM losses were estimated to 49 euros per stall for the first year after infection, and to 8 euros per stall annually averaged over the 10 years after herd infection for a 200 cow stall herd with very good management. In contrast, a 200 cow stall herd...

  14. International demands for retrofitting, trends in the nuclear industry, safety margins, concepts and options for retrofit; Nachfrage nach Nachruestungen international; industrielle Trends; Rolle von Sicherheitsmargen, Nachruestkonzepte und -moeglichkeiten

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Rolf; Stoll, Uwe; Grasnick, Claudius [AREVA GmbH, Erlangen (Germany). E and P, P-G

    2016-02-15

    The serious accidents at Fukushima in 2011 pointed out the missing implementation of existing international safety standards for nuclear power plants as also new aspects for nuclear safety. The main safety aspects in the aftermath of Fukushima are: robustness against internal and external impacts; sufficient safety margins; prolonged periods for safety measures; inherent and passive systems and mechanisms; enhanced independent operation of the plant in case of external failures; independent long-term supply with AC; accident management procedures; enhanced retention of radionuclides. Technologies for retrofit are available and are under implementation with respect to the demands and options in the countries using nuclear power.

  15. The ASN and nuclear facilities: towards a strengthening of safety margins

    International Nuclear Information System (INIS)

    Anon.

    2012-01-01

    The new measures taken by the French Nuclear Safety Authority (ASN) as a consequence of the complementary safety assessments performed recently on nuclear facilities are reviewed in this article. The main measures are the following. Concerning EDF: -) the setting of a hard core of measures in order to assure a few safety-vital functions in any case, for instance one of this measures is to bunker some of the emergency diesel sets; -) the setting of a rapid intervention force able to provide any damaged nuclear plant with extra means in cooling and power in a very short time; -) a better training of the staff in case of severe accident. Concerning AREVA: the setting of robust means to assure the water supply of the fuel pool at La Hague plant and the setting of efficient means to mitigate the consequences of a leak of ClF 3 , HF, UF 6 in the premises of Eurodif, Socatri, TU5, GB 2 and Comurhex. Concerning CEA: -) the removal of fissile materials from the Masurca facility, -) the setting up of improved means concerning flood and sodium fires at the Phenix reactor, -) the setting up of improved means concerning the loss of coolant at the Osiris reactor, -) the setting up of improved means in case of flood, earthquake and loss of coolant at the Jules Horowitz reactor. (A.C.)

  16. Uncertainties assessment for safety margins evaluation in MTR reactors core thermal-hydraulic design

    International Nuclear Information System (INIS)

    Gimenez, M.; Schlamp, M.; Vertullo, A.

    2002-01-01

    This report contains a bibliographic review and a critical analysis of different methodologies used for uncertainty evaluation in research reactors core safety related parameters. Different parameters where uncertainties are considered are also presented and discussed, as well as their intrinsic nature regarding the way their uncertainty combination must be done. Finally a combined statistical method with direct propagation of uncertainties and a set of basic parameters as wall and DNB temperatures, CHF, PRD and their respective ratios where uncertainties should be considered is proposed. (author)

  17. New Safety Margins for Melanoma Surgery: Nice Possibility for Drinking of "Just That Cup of Coffee"?

    Science.gov (United States)

    Tchernev, Georgi; Chokoeva, Anastasiya Atanasova

    2017-06-15

    The American Joint Committee on Cancer (AJCC's) skin melanoma surgical treatment recommendations from 2011 are characterised by a prima facie "freedom of choice" regarding how extensive should be the excisions for melanomas with tumour thickness up to 2 mm and melanoma in situ. It is unclear why the recommended surgical security margins vary between 0.5 and 1 cm for melanoma in situ, whereas for melanomas with a tumour thickness of up to 1.99 mm, the range of variation is also between 1 and 2 cm, without specifying when the surgical field should be broader and, narrower, accordingly. This "uncertainty or lack of intent" of the guilders often leads to the same surgical approach to melanomas at different stages, or to a different approach in cases of melanomas at the same stage, in contrast. Therefore, this should be defined as wrong, logically. We present 3 patients with cutaneous melanomas, treated with similar fields of surgical security. Current issues, generated within the framework of melanoma's surgery guided by the recommendations of the AJCC are also discussed. A new surgical approach in patients with melanoma is recommended, discussed for the first time in world literature. We hypothesize that the introduction of a certain recommendations for a 2 cm surgical field in all directions during the initial excision, combined with the parallel performance of a sentinel lymph node biopsy, will lead in fact to several important advantages: 1) avoiding of the secondary excision in at least 70% - 90% of the patients (depending on the tumor thickness), 2) minimizing the risk of lymphatic effusion change and misinterpretation of the sentinel lymph node biopsy's results in patients with secondary excision; 3) optimization of the surgical team's work; 4) minimizing the possibility of unprepared/uninformed personnel to take part in decisions for treating a specific disease such as skin melanoma, 4) facilitating the appropriate patients' group selection at the appropriate

  18. A summary of the low upper shelf toughness safety margin issue

    International Nuclear Information System (INIS)

    Merkle, J.G.

    1991-01-01

    The low upper shelf toughness issue has a long history, beginning with the choice of materials for the submerged arc welding process, but also potentially involving the use of A302-B plate. Criteria for vessels containing low upper shelf materials have usually been expressed in terms of the Charpy upper shelf impact energy. Although these criteria have had several different bases, the range of limiting values for wall thicknesses approaching 229 mm (9 in.) has remained between 54 to 68J (40 to 50 ft lbs). Allowable values for vessels with thinner walls and/or only circumferential low upper shelf welds might conceivably be less. A decision on criteria to be incorporated into the ASME Code is now being made. Choices to be made concern the method for estimating the decrease in upper shelf impact energy, flaw geometry for circumferential welds, statistical significance of toughness values, the choice between J D and J M , reference pressure, safety factors and the inclusion of tearing stability calculations by means of R curve extrapolation. NRC research programs have contributed significantly to the resolution of the low upper shelf issue. These programs embrace all aspects of the issue, including material characterization, large scale testing, analysis and criteria development. 52 refs., 5 figs

  19. Seismic safety margins research program. Phase I. Project VII: systems analysis specifications of computational approach

    International Nuclear Information System (INIS)

    Collins, J.D.; Hudson, J.M.; Chrostowski, J.D.

    1979-02-01

    A computational methodology is presented for the prediction of core melt probabilities in a nuclear power plant due to earthquake events. The proposed model has four modules: seismic hazard, structural dynamic (including soil-structure interaction), component failure and core melt sequence. The proposed modules would operate in series and would not have to be operated at the same time. The basic statistical approach uses a Monte Carlo simulation to treat random and systematic error but alternate statistical approaches are permitted by the program design

  20. Seismic Safety Margins Research Program. Phase I final report - Subsystem response (Project V)

    International Nuclear Information System (INIS)

    Shieh, L.C.; Chuang, T.Y.; O'Connell, W.J.

    1981-10-01

    This document reports on (1) the computation of the responses of subsystems, given the input subsystem support motion for components and systems whose failure can lead to an accident sequence (radioactive release), and (2) the results of a sensitivity study undertaken to determine the contributions of the several links in the seismic methodology chain (SMC) - seismic input (SI), soil-structure interaction (SSI), structure response (STR), and subsystem response (SUB) - to the uncertainty in subsystem response. For the singly supported subsystems (e.g., pumps, turbines, electrical control panels, etc.), we used the spectral acceleration response of the structure at the point where the subsystem components were mounted. For the multiple supported subsystems, we developed 13 piping models of five safety-related systems, and then used the pseudostatic-mode method with multisupport input motion to compute the response parameters in terms of the parameters used in the fragility descriptions (i.e., peak resultant accelerations for valves and peak resultant moments for piping). Damping and frequency were varied to represent the sources of modeling and random uncertainty. Two codes were developed: a modified version of SAPIV which assembles the piping supports into groups depending on the support's location relative to the attached structure, and SAPPAC a stand-alone modular program from which the time-history analysis module is extracted. On the basis of our sensitivity study, we determined that the variability in the combined soil-structure interaction, structural response, and subsystem response areas contribute more to uncertainty in subsystem response than does the variability in the seismic input area, assuming an earthquake within the limited peak ground acceleration range, i.e., 0.15 to 0.30g. The seismic input variations were in terms of different earthquake time histories. (author)

  1. Reliability of COPVs Accounting for Margin of Safety on Design Burst

    Science.gov (United States)

    Murthy, Pappu L.N.

    2012-01-01

    In this paper, the stress rupture reliability of Carbon/Epoxy Composite Overwrapped Pressure Vessels (COPVs) is examined utilizing the classic Phoenix model and accounting for the differences between the design and the actual burst pressure, and the liner contribution effects. Stress rupture life primarily depends upon the fiber stress ratio which is defined as the ratio of stress in fibers at the maximum expected operating pressure to actual delivered fiber strength. The actual delivered fiber strength is calculated using the actual burst pressures of vessels established through burst tests. However, during the design phase the actual burst pressure is generally not known and to estimate the reliability of the vessels calculations are usually performed based upon the design burst pressure only. Since the design burst is lower than the actual burst, this process yields a much higher value for the stress ratio and consequently a conservative estimate for the reliability. Other complications arise due to the fact that the actual burst pressure and the liner contributions have inherent variability and therefore must be treated as random variables in order to compute the stress rupture reliability. Furthermore, the model parameters, which have to be established based on stress rupture tests of subscale vessels or coupons, have significant variability as well due to limited available data and hence must be properly accounted for. In this work an assessment of reliability of COPVs including both parameter uncertainties and physical variability inherent in liner and overwrap material behavior is made and estimates are provided in terms of degree of uncertainty in the actual burst pressure and the liner load sharing.

  2. Material presented to advisory committee on reactor safeguards, subcommittee on extreme external phenomena, January 29-30, 1981, Los Angeles, California. Seismic safety margins research program

    International Nuclear Information System (INIS)

    Smith, P.D.; Bernreuter, D.L.; Bohn, M.P.; Chuang, T.Y.; Cummings, G.E.; Dong, R.G.; Johnson, J.J.; Wells, J.E.

    1981-01-01

    The January 29-30, 1981, meeting of the Advisory Committee on Reactor Safeguards (ACRS), Subcommittee on Extreme External Phenomena, mark the close of Phase I efforts on the Seismic Safety Margins Research Program (SSMRP). Presentations at the meeting focused on results produced. These included computer codes, response computations, failure and release probabilities, data bases, and fragilities and parameter characteristics

  3. Assessment of occupational exposure due to external sources of radiation. Safety guide

    International Nuclear Information System (INIS)

    2000-01-01

    Occupational exposure to ionizing radiation can occur in a range of industries, medical institutions, educational and research establishments and nuclear fuel cycle facilities. Adequate radiation protection of workers is essential for the safe and acceptable use of radiation, radioactive materials and nuclear energy. The three Safety Guides on occupational radiation protection are jointly sponsored by the IAEA and the International Labour Office. The Agency gratefully acknowledges the contribution of the European Commission to the development of the present Safety Guide. The present Safety Guide addresses the assessment of exposure due to external sources of radiation in the workplace. Such exposure can result from a number of sources within a workplace, and the monitoring of workers and the workplace in such situations is an integral part of any occupational radiation protection programme. The assessment of exposure due to external radiation sources depends critically upon knowledge of the radiation type and energy and the conditions of exposure. The present Safety Guide reflects the major changes over the past decade in international practice in external dose assessment

  4. Assessment of occupational exposure due to external sources of radiation. Safety guide

    International Nuclear Information System (INIS)

    2004-01-01

    Occupational exposure to ionizing radiation can occur in a range of industries, medical institutions, educational and research establishments and nuclear fuel cycle facilities. Adequate radiation protection of workers is essential for the safe and acceptable use of radiation, radioactive materials and nuclear energy. The three Safety Guides on occupational radiation protection are jointly sponsored by the IAEA and the International Labour Office. The Agency gratefully acknowledges the contribution of the European Commission to the development of the present Safety Guide. The present Safety Guide addresses the assessment of exposure due to external sources of radiation in the workplace. Such exposure can result from a number of sources within a workplace, and the monitoring of workers and the workplace in such situations is an integral part of any occupational radiation protection programme. The assessment of exposure due to external radiation sources depends critically upon knowledge of the radiation type and energy and the conditions of exposure. The present Safety Guide reflects the major changes over the past decade in international practice in external dose assessment

  5. Assessment of occupational exposure due to external sources of radiation. Safety guide

    International Nuclear Information System (INIS)

    1999-01-01

    Occupational exposure to ionizing radiation can occur in a range of industries, medical institutions, educational and research establishments and nuclear fuel cycle facilities. Adequate radiation protection of workers is essential for the safe and acceptable use of radiation, radioactive materials and nuclear energy. The three Safety Guides on occupational radiation protection are jointly sponsored by the IAEA and the International Labour Office. The Agency gratefully acknowledges the contribution of the European Commission to the development of the present Safety Guide. The present Safety Guide addresses the assessment of exposure due to external sources of radiation in the workplace. Such exposure can result from a number of sources within a workplace, and the monitoring of workers and the workplace in such situations is an integral part of any occupational radiation protection programme. The assessment of exposure due to external radiation sources depends critically upon knowledge of the radiation type and energy and the conditions of exposure. The present Safety Guide reflects the major changes over the past decade in international practice in external dose assessment

  6. Rethinking the Zircaloy Embrittlement Criteria and Its Impact on Safety Margin

    Energy Technology Data Exchange (ETDEWEB)

    Lee, You Ho; Kim, Bo Kyung; No, Hee Cheon [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    These fuel rod failure modes include integral thermal shock fracture, and impact tests. It is quite remarkable to see that the proposed Zircaloy embrittlemt criteria attained from ring compression tests, in general, successfully assure structural integrity of fuel rods subject to relevant failure modes in accidents. This fact demonstrates that ductility of Zircaloy is the key metric to structural integrity of fuel rods. However, the Zircaloy embrittlement criteria set in 1970s inevitably pose limitations that have become increasingly important for today's nuclear fuel and reactor operations. In particular, the criteria do not take into account the steady-state hydrogen embrittlement with burnup. This may be understandable considering the markedly lower discharge burnup in 1970s compared to that of today. The revision of the rule has been already conducted by the U.S NRC to account for high burnup effects on ECR while the temperature limit remains unchanged. The newly proposed rule of the U.S NRC stick to the similar ring compression tests conducted in the early 1970s. In the monumental experimental investigation of Hobson and Rittenhouse in 1972 and 1973, the experimental evidence for the current 1204oC was first addressed. The study found a reasonably accurate correlation between zero ductility temperature and the sum of alpha and oxide layer thickness for the specimens oxidized below 2200oF (1204 .deg. C). However, in spite of the similar oxidation degree, specimens oxidized at 2400 .deg. F (1315 deg. C) were markedly more brittle than specimens oxidized at 2200 .deg. F (1204 .deg. C). The study explained this by the increase in solid-solution hardening due to a higher oxygen solubility at a higher temperature. Such a nice experimental correlation attained between the nil ductility temperature and the remaining beta layer thickness fraction below 1204 .deg. C has become a critical basis for the current temperature limit; at 1315 .deg. C- thecorrelation

  7. Modeling safety risk perception due to mobile phone distraction among four wheeler drivers

    Directory of Open Access Journals (Sweden)

    Raghunathan Rajesh

    2017-04-01

    Full Text Available Nowadays, there is an increasing trend in the use of information and communication technology devices in new vehicles. Due to these increasing service facilities, driver distraction has become a major concern for transportation safety. To reduce safety risks, it is crucial to understand how distracting activities affect driver behavior at different levels of vehicle control. The objective of this work is to understand how the vehicle and driver characteristics influence mobile phone usage while driving and associated risk perception of road safety incidents. Based on literature review, a man–machine framework for distracted driving and a mobile phone distraction model is presented. The study highlights the findings from a questionnaire survey conducted in Kerala, India. The questionnaire uses a 5-point Likert scale. Responses from 1203 four-wheeler drivers are collected using random sampling approach. The questionnaire items associated with three driver-drive characteristics are: (i Human Factors (age, experience, emotional state, behavior of driver, (ii Driver space (meter, controls, light, heat, steering, actuators of vehicle, (iii Driving conditions (speed, distance, duration, traffic, signals. This mobile phone distraction model is tested using structural equation modeling procedure. The study indicates that among the three characteristics, ‘Human Factors’ has the highest influence on perceived distraction due to mobile phones. It is also observed that safety risk perception due to mobile phone usage while driving is moderate. The practical relevance of the study is to place emphasis on behavior-based controls and to focus on strategies leveraging perception of distraction due to mobile phones while driving.

  8. Seismic safety margins research program. Phase I final report - Plant/site selection and data collection (Project I)

    International Nuclear Information System (INIS)

    Chuang, T.Y.

    1981-07-01

    Project I of Phase I of the Seismic Safety Margins Research Program (SSMRP) comprised two parts: the selection of a representative nuclear power plant/site for study in Phase I and the collection of data needed by the other SSMRP projects. Unit 1 of the Zion Nuclear Power Plant in Zion, Illinois, was selected for the SSMRP Phase I studies. Unit 1 of the Zion plant has been validated as a good choice for the Phase I study plant. Although no single nuclear power plant can represent all such plants equally well, selection criteria were developed to maximize the generic implications of Phase I of the SSMRP. On the basis of the selection criteria, the Zion plant and its site were found to be reasonably representative of operating and future plants with regard to its nuclear steam supply system; the type of containment structure (prestressed concrete); its electrical capacity (1100 MWe); its location (the Midwest); the peak seismic acceleration used for design (0.17g); and the properties of the underlying soil (the low-strain shear-wave velocity is 1650 ft/s in a 50- to 100-ft-thick layer of soil overlying sedimentary bedrock). (author)

  9. Quantifying reactor safety margins: Part 1: An overview of the code scaling, applicability, and uncertainty evaluation methodology

    International Nuclear Information System (INIS)

    Boyack, B.E.; Duffey, R.B.; Griffith, P.

    1988-01-01

    In August 1988, the Nuclear Regulatory Commission (NRC) approved the final version of a revised rule on the acceptance of emergency core cooling systems (ECCS) entitled ''Emergency Core Cooling System; Revisions to Acceptance Criteria.'' The revised rule states an alternate ECCS performance analysis, based on best-estimate methods, may be used to provide more realistic estimates of plant safety margins, provided the licensee quantifies the uncertainty of the estimates and included that uncertainty when comparing the calculated results with prescribed acceptance limits. To support the revised ECCS rule, the NRC and its contractors and consultants have developed and demonstrated a method called the Code Scaling, Applicability, and Uncertainty (CSAU) evaluation methodology. It is an auditable, traceable, and practical method for combining quantitative analyses and expert opinions to arrive at computed values of uncertainty. This paper provides an overview of the CSAU evaluation methodology and its application to a postulated cold-leg, large-break loss-of-coolant accident in a Westinghouse four-loop pressurized water reactor with 17 /times/ 17 fuel. The code selected for this demonstration of the CSAU methodology was TRAC-PF1/MOD1, Version 14.3. 23 refs., 5 figs., 1 tab

  10. Additional costs to Finnish dairy farms due to occupational safety and health

    Directory of Open Access Journals (Sweden)

    Tapio Klen

    1988-03-01

    Full Text Available The additional costs incurred by work safety measures to dairy farms were estimated by interviewing 95 dairy farmers and inspecting with them production buildings, machines and the need for personal protective devices at a commune. The present value of the implemented safety and health improvements rose to FIM 22 000 per farm in 1983. About FIM 17000 were due to the tractors, FIM 3 000 to the cow houses and FIM 2 000 to other machines and tools than tractors. The protective equipment of tractors caused the annual maintenance cost of FIM 4 350 and cow house FIM 650, if the interest rate were 10 %. The annual total cost was over FIM 6 000. The replacement value would have been about FIM 31 000 in 1983. If all deficiences still remaining in 1983 had been corrected at once, the total cost would have been about FIM 12000 per farm, which leads to an annual cost of FIM 3 100. As for still remaining deficiencies, the study suggested need for an annual cost of about FIM 1 500 due to personal protectors. Half of this sum was due to need for the acquisition of personal safety equipment for forest work. Correcting the safety and health deficiencies of the cowshed and agricultural machines would produce each an annual cost of about FIM 800 per farm. The present value of the labor protection investments in 1983 was FIM 22 000 per farm, and there still remained need to invest an additional FIM 12000 in order to eliminate the remaining deficiencies. So, the theoretical total of the annual maintenance cost would have been FIM 6 600—9 200 per farm depending on the interest rate. Because the study concerned only one commune, the results cannot be generalized to the whole country.

  11. Assessment of occupational exposure due to intakes of radionuclides. Safety guide

    International Nuclear Information System (INIS)

    2004-01-01

    Occupational exposure due to radioactive materials can occur as a result of various human activities. These include work associated with the different stages of the nuclear fuel cycle, the use of radioactive sources in medicine, scientific research, agriculture and industry, and occupations which involve the handling of materials containing enhanced concentrations of naturally occurring radionuclides. In order to control this exposure, it is necessary to be able to assess the magnitude of the doses involved. Three interrelated Safety Guides, prepared jointly by the IAEA and the International Labour Office (ILO), provide guidance on the application of the requirements of the Basic Safety Standards with respect to occupational exposure. Reference [3] gives general advice on the exposure conditions for which monitoring programmes should be set up to assess radiation doses arising from external radiation and from intakes of radionuclides by workers. More specific guidance on the assessment of doses from external sources of radiation can be found in Ref. [4] and the present Safety Guide deals with intakes of radioactive materials. Recommendations related to occupational radiation protection have also been developed by the International Commission on Radiological Protection (ICRP) [5]. These and other current recommendations of the ICRP [6] have been taken into account in preparing this Safety Guide. The purpose of this Safety Guide is to provide guidance for regulatory authorities on conducting assessments of intakes of radioactive material arising from occupational exposure. This Guide will also be useful to those concerned with the planning, management and operation of occupational monitoring programmes, and to those involved in the design of equipment for use in internal dosimetry and workplace monitoring

  12. Assessment of occupational exposure due to intakes of radionuclides. Safety guide

    International Nuclear Information System (INIS)

    2000-01-01

    Occupational exposure due to radioactive materials can occur as a result of various human activities. These include work associated with the different stages of the nuclear fuel cycle, the use of radioactive sources in medicine, scientific research, agriculture and industry, and occupations which involve the handling of materials containing enhanced concentrations of naturally occurring radionuclides. In order to control this exposure, it is necessary to be able to assess the magnitude of the doses involved. Three interrelated Safety Guides, prepared jointly by the IAEA and the International Labour Office (ILO), provide guidance on the application of the requirements of the Basic Safety Standards with respect to occupational exposure. Reference [3] gives general advice on the exposure conditions for which monitoring programmes should be set up to assess radiation doses arising from external radiation and from intakes of radionuclides by workers. More specific guidance on the assessment of doses from external sources of radiation can be found in Ref. [4] and the present Safety Guide deals with intakes of radioactive materials. Recommendations related to occupational radiation protection have also been developed by the International Commission on Radiological Protection (ICRP) [5]. These and other current recommendations of the ICRP [6] have been taken into account in preparing this Safety Guide. The purpose of this Safety Guide is to provide guidance for regulatory authorities on conducting assessments of intakes of radioactive material arising from occupational exposure. This Guide will also be useful to those concerned with the planning, management and operation of occupational monitoring programmes, and to those involved in the design of equipment for use in internal dosimetry and workplace monitoring

  13. Assessment of occupational exposure due to intakes of radionuclides. Safety guide

    International Nuclear Information System (INIS)

    2001-01-01

    Occupational exposure due to radioactive materials can occur as a result of various human activities. These include work associated with the different stages of the nuclear fuel cycle, the use of radioactive sources in medicine, scientific research, agriculture and industry, and occupations which involve the handling of materials containing enhanced concentrations of naturally occurring radionuclides. In order to control this exposure, it is necessary to be able to assess the magnitude of the doses involved. Three interrelated Safety Guides, prepared jointly by the IAEA and the International Labour Office (ILO), provide guidance on the application of the requirements of the Basic Safety Standards with respect to occupational exposure. Reference [3] gives general advice on the exposure conditions for which monitoring programmes should be set up to assess radiation doses arising from external radiation and from intakes of radionuclides by workers. More specific guidance on the assessment of doses from external sources of radiation can be found in Ref. [4] and the present Safety Guide deals with intakes of radioactive materials. Recommendations related to occupational radiation protection have also been developed by the International Commission on Radiological Protection (ICRP) [5]. These and other current recommendations of the ICRP [6] have been taken into account in preparing this Safety Guide. The purpose of this Safety Guide is to provide guidance for regulatory authorities on conducting assessments of intakes of radioactive material arising from occupational exposure. This Guide will also be useful to those concerned with the planning, management and operation of occupational monitoring programmes, and to those involved in the design of equipment for use in internal dosimetry and workplace monitoring

  14. Assessment of occupational exposure due to intakes of radionuclides. Safety guide

    International Nuclear Information System (INIS)

    2002-01-01

    Occupational exposure due to radioactive materials can occur as a result of various human activities. These include work associated with the different stages of the nuclear fuel cycle, the use of radioactive sources in medicine, scientific research, agriculture and industry, and occupations which involve the handling of materials containing enhanced concentrations of naturally occurring radionuclides. In order to control this exposure, it is necessary to be able to assess the magnitude of the doses involved. Three interrelated Safety Guides, prepared jointly by the IAEA and the International Labour Office (ILO), provide guidance on the application of the requirements of the Basic Safety Standards with respect to occupational exposure. Reference [3] gives general advice on the exposure conditions for which monitoring programmes should be set up to assess radiation doses arising from external radiation and from intakes of radionuclides by workers. More specific guidance on the assessment of doses from external sources of radiation can be found in Ref. [4] and the present Safety Guide deals with intakes of radioactive materials. Recommendations related to occupational radiation protection have also been developed by the International Commission on Radiological Protection (ICRP) [5]. These and other current recommendations of the ICRP [6] have been taken into account in preparing this Safety Guide. The purpose of this Safety Guide is to provide guidance for regulatory authorities on conducting assessments of intakes of radioactive material arising from occupational exposure. This Guide will also be useful to those concerned with the planning, management and operation of occupational monitoring programmes, and to those involved in the design of equipment for use in internal dosimetry and workplace monitoring

  15. Assessment of occupational exposure due to intakes of radionuclides. Safety guide

    International Nuclear Information System (INIS)

    1999-01-01

    Occupational exposure due to radioactive materials can occur as a result of various human activities. These include work associated with the different stages of the nuclear fuel cycle, the use of radioactive sources in medicine, scientific research, agriculture and industry, and occupations which involve the handling of materials containing enhanced concentrations of naturally occurring radionuclides. In order to control this exposure, it is necessary to be able to assess the magnitude of the doses involved. Three interrelated Safety Guides, prepared jointly by the IAEA and the International Labour Office (ILO), provide guidance on the application of the requirements of the Basic Safety Standards with respect to occupational exposure. Reference [3] gives general advice on the exposure conditions for which monitoring programmes should be set up to assess radiation doses arising from external radiation and from intakes of radionuclides by workers. More specific guidance on the assessment of doses from external sources of radiation can be found in Ref. [4] and the present Safety Guide deals with intakes of radioactive materials. Recommendations related to occupational radiation protection have also been developed by the International Commission on Radiological Protection (ICRP) [5]. These and other current recommendations of the ICRP [6] have been taken into account in preparing this Safety Guide. The purpose of this Safety Guide is to provide guidance for regulatory authorities on conducting assessments of intakes of radioactive material arising from occupational exposure. This Guide will also be useful to those concerned with the planning, management and operation of occupational monitoring programmes, and to those involved in the design of equipment for use in internal dosimetry and workplace monitoring

  16. Co-ordination of growth, gas exchange and hydraulics define the carbon safety margin in tree species with contrasting drought strategies.

    Science.gov (United States)

    Mitchell, P J; O'Grady, A P; Tissue, D T; Worledge, D; Pinkard, E A

    2014-05-01

    Gas exchange, growth, water transport and carbon (C) metabolism diminish during drought according to their respective sensitivities to declining water status. The timing of this sequence of declining physiological functions may determine how water and C relations compromise plant survival. In this paper, we test the hypothesis that the degree of asynchrony between declining C supply (photosynthesis) and C demand (growth and respiration) determines the rate and magnitude of changes in whole-plant non-structural carbohydrates (NSC) during drought. Two complementary experiments using two tree species (Eucalyptus globulus Labill. and Pinus radiata D. Don) with contrasting drought response strategies were performed to (i) assess changes in radial stem growth, transpiration, leaf water potential and gas exchange in response to chronic drought, and (ii) evaluate the concomitant impacts of these drought responses on the temporal patterns of NSC during terminal drought. The three distinct phases of water stress were delineated by thresholds of growth cessation and stomatal closure that defined the 'carbon safety margin' (i.e., the difference between leaf water potential when growth is zero and leaf water potential when net photosynthesis is zero). A wider C safety margin in E. globulus was defined by an earlier cessation of growth relative to photosynthesis that reduced the demand for NSC while maintaining C acquisition. By contrast, the narrower C safety margin in P. radiata was characterized by a synchronous decline in growth and photosynthesis, whereby growth continued under a declining supply of NSC from photosynthesis. The narrower C safety margin in P. radiata was associated with declines in starch concentrations after ∼ 90 days of chronic drought and significant depletion of starch in all organs at mortality. The observed divergence in the sensitivity of drought responses is indicative of a potential trade-off between maintaining hydraulic safety and adequate C

  17. Seismic structural fragility investigation for the Zion Nuclear Power Plant. Seismic safety margins research program (phase 1)

    International Nuclear Information System (INIS)

    Wesley, D.A.; Hashimoto, P.S.

    1981-10-01

    An evaluation of the seismic capacity of the essential structures for the Zion Nuclear Power Plant in Zion, Illinois, was conducted as part of the Seismic Safety Margins Research Program (SSMRP). The structures included the reactor containment building, the turbine/auxiliary building, and the crib house (intake structure). The evaluation was devoted to seismically induced failures rather than those resulting from combined Loss of Coolant Accident (LOCA) or other extreme load combinations. The seismic loads used in the investigation were based on elastic analyses. The loads for the reactor containment and turbine/auxiliary buildings were developed by Lawrence Livermore Laboratory using time history analyses. The loads used for the crib house were the original seismic design loads developed by Sargent and Lundy. No non-linear seismic analyses were conducted. The seismic capacity of the structures accounted for the actual concrete and steel material properties including the aging of the concrete. Median centered properties were used throughout the evaluation including levels of damping considered appropriate for structures close to collapse as compared to the more conservative values used for design. The inelastic effects were accounted for using ductility modified response spectrum techniques based on system ductility ratios expected for structures near collapse. Sources of both inherent randomness and uncertainties resulting from lack of knowledge or approximations in analytical modelling were considered in developing the dispersion of the structural dynamic characteristics. Coefficients of variation were developed assuming lognormal distributions for all variables. The earthquake levels for many of the seismically induced failure modes are so high as to be considered physically incredible. (author)

  18. Soil-structure interaction for transient loads due to safety relief valve discharges

    International Nuclear Information System (INIS)

    Tseng, W.S.; Tsai, N.C.

    1978-01-01

    Dynamic responses of BWR Mark II containment structures subjected to axisymmetric transient pressure loadings due to simultaneous safety relief valve discharges were investigated using finite element analysis, including the soil-structure interaction effect. To properly consider the soil-structure interaction effect, a simplified lumped parameter foundation model and axisymmetric finite element foundation model with viscous boundary impedance are used. Analytical results are presented to demonstrate the effectiveness of the simplified foundation model and to exhibit the dynamic response behavior of the structure as the transient loading frequency and the foundation rigidity vary. The impact of the dynamic structural response due to this type of loading on the equipment design is also discussed. (Auth.)

  19. Effect of Smaller Left Ventricular Capture Threshold Safety Margins to Improve Device Longevity in Recipients of Cardiac Resynchronization-Defibrillation Therapy.

    Science.gov (United States)

    Steinhaus, Daniel A; Waks, Jonathan W; Collins, Robert; Kleckner, Karen; Kramer, Daniel B; Zimetbaum, Peter J

    2015-07-01

    Device longevity in cardiac resynchronization therapy (CRT) is affected by the pacing capture threshold (PCT) and programmed pacing amplitude of the left ventricular (LV) pacing lead. The aims of this study were to evaluate the stability of LV pacing thresholds in a nationwide sample of CRT defibrillator recipients and to determine potential longevity improvements associated with a decrease in the LV safety margin while maintaining effective delivery of CRT. CRT defibrillator patients in the Medtronic CareLink database were eligible for inclusion. LV PCT stability was evaluated using ≥2 measurements over a 14-day period. Separately, a random sample of 7,250 patients with programmed right atrial and right ventricular amplitudes ≤2.5 V, LV thresholds ≤ 2.5 V, and LV pacing ≥90% were evaluated to estimate theoretical battery longevity improvement using LV safety margins of 0.5 and 1.5 V. Threshold stability analysis in 43,256 patients demonstrated LV PCT stability of 1 V had the greatest increases in battery life (mean increase 0.86 years, 95% confidence interval 0.85 to 0.87). In conclusion, nearly all CRT defibrillator patients had LV PCT stability <1.0 V. Decreasing the LV safety margin from 1.5 to 0.5 V provided consistent delivery of CRT for most patients and significantly improved battery longevity. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. A novel respiratory motion compensation strategy combining gated beam delivery and mean target position concept - A compromise between small safety margins and long duty cycles

    International Nuclear Information System (INIS)

    Guckenberger, Matthias; Kavanagh, Anthony; Webb, Steve; Brada, Michael

    2011-01-01

    Purpose: To evaluate a novel respiratory motion compensation strategy combining gated beam delivery with the mean target position (MTP) concept for pulmonary stereotactic body radiotherapy (SBRT). Materials and methods: Four motion compensation strategies were compared for 10 targets with motion amplitudes between 6 mm and 31 mm: the internal target volume concept (plan ITV ); the MTP concept where safety margins were adapted based on 4D dose accumulation (plan MTP ); gated beam delivery without margins for motion compensation (plan gated ); a novel approach combining gating and the MTP concept (plan gated and MTP ). Results: For 5/10 targets with an average motion amplitude of 9 mm, the differences in the mean lung dose (MLD) between plan gated and plan MTP were gated and MTP . Despite significantly shorter duty cycles, plan gated reduced the MLD by gated and MTP . The MLD was increased by 18% in plan MTP compared to that of plan gated and MTP . Conclusions: For pulmonary targets with motion amplitudes >10-15 mm, the combination of gating and the MTP concept allowed small safety margins with simultaneous long duty cycles.

  1. 75 FR 14243 - Pipeline Safety: Girth Weld Quality Issues Due to Improper Transitioning, Misalignment, and...

    Science.gov (United States)

    2010-03-24

    ... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No..., and Welding Practices of Large Diameter Line Pipe AGENCY: Pipeline and Hazardous Materials Safety... bulletin to notify owners and operators of recently constructed large diameter natural gas pipeline and...

  2. Comparison of APR1400 safety between brake site and shin-Kori site Due to the difference in the climate conditions

    International Nuclear Information System (INIS)

    Yoon, Ho Joon; Lee, Jeong Ik; Lee, Jeong Ik

    2012-01-01

    Brake Nuclear Power Plant (BNPP) is now under the construction based on APR1400 designed by Korean Electric Power Corporation (KEPCO). APR1400 is a two loop pressurized water reactor, the nuclear steam supply system (NSSS) US designed for about put of 4,000 MWt, with a corresponding electrical output of approximately 1,390 MWe. The first APR1400 (SKN 3 and 4) constructed in Shin-Kori, Korea has been modified according to the surrounding environment of the United Arab Emirates. In this paper, authors would like to compare safety issues between B NPP and Skin due to the changes of surroundings, since the site characteristics are very different. For instance, the mean annual air temperature in the UAE is 28 .deg. C and the peak air temperature was recorded as 48.8 .deg. C. Sea temperatures are varying from 17. deg. C in January to 35. deg. C in August, while that of Korea is in 9-16. deg. C range. Hot climate of UAE and the malfunction of HVAC system can lead the increasing of the water temperature in safety injection system (SIS). The heated water in SIS may affect the safety margin of the peak cladding temperature (PCT). The change of PCT and response time according to design basis accident scenarios such as large break LOCA are analyzed in detail. To evaluate such effect, Mars code was utilized to evaluate assumed condition by KAIST and the analyses of the results were carried out by Khalifa Univ.

  3. Inquiry relating to safety due to modification of usage of nuclear fuel material (establishment of waste safety testing facility) in Tokai Laboratory, Japan Atomic Energy Research Institute

    International Nuclear Information System (INIS)

    1979-01-01

    Application was made to the director of the Science and Technology Agency (STA) for the license relating to the modification of usage of nuclear fuel material (the establishment of waste safety testing facility) from the director of the Japan Atomic Energy Research Institute on November 30, 1978. After passing through the safety evaluation in the Nuclear Safety Bureau of STA, inquiry was conducted to the head of the Atomic Energy Safety Commission (AESC) on June 6, 1979, from the director of the STA. The head of AESC directed to conduct the safety examination to the head of the Nuclear Fuel Safety Examination Specialist Committee on June 7, 1979. The content of the modification of usage of nuclear fuel material is the establishment of waste safety testing facility to study and test the safety relating to the treatment and disposal of high level radioactive liquid wastes due to the reprocessing of spent fuel. As for the results of the safety examination, the siting of the waste safety testing facility which is located in the Tokai Laboratory, Japan Atomic Energy Research Institute (JAERI), and the test plan of the glass solidification of high level radioactive liquid are presented as the outline of the study plan. The building, main equipments including six cells, the isolation room and the glove box, the storage, and the disposal facilities for gas, liquid and solid wastes are explained as the outline of the facilities. Concerning the items from the viewpoint of safety, aseismatic design, slightly vacuum operation, shielding, decay heat removal, fire protection, explosion protection, criticality management, radiation management and environmental effect were evaluated, and the safety was confirmed. (Nakai, Y.)

  4. Safety analysis of dual purpose metal cask subjected to impulsive loads due to aircraft engine crash

    International Nuclear Information System (INIS)

    Shirai, Koji; Namba, Kosuke; Saegusa, Toshiari

    2009-01-01

    In Japan, the first Interim Storage Facility of spent nuclear fuel away from reactor site is being planned to start its commercial operation around 2010, in use of dual-purpose metal cask in the northern part of Main Japan Island. Business License Examination for safety design approval has started since March, 2007. To demonstrate the more scientific and rational performance of safety regulation activities on each phase for the first license procedure, CREPEI has executed demonstration tests with full scale casks, such as drop tests onto real targets without impact limiters and seismic tests subjected to strong earthquake motions. Moreover, it is important to develop the knowledge for the inherent security of metal casks under extreme mechanical-impact conditions, especially for increasing interest since the terrorist attacks from 11th September 2001. This paper presents dynamic mechanical behavior of the metal cask lid closure system caused by direct aircraft engine crash and describes calculated results (especially, leak tightness based on relative dynamic displacements between metallic seals). Firstly, the local penetration damage of the interim storage facility building by a big passenger aircraft engine research (diameter 2.7m, length 4.3m, weight 4.4ton, impact velocity 90m/s) has been examined. The reduced velocity is calculated by the local damage formula for concrete structure with its thickness of 70cm. The load vs. time function for this reduced velocity (60m/s) is estimated by the impact analysis using Finite Element code LS-DYNA with the full scale engine model onto a hypothetically rigid target. Secondly, as the most critical scenarios for the metal cask, two impact scenarios (horizontal impact hitting the cask and vertical impact onto the lid metallic seal system) are chosen. To consider the geometry of all bolts for two lids, the gasket reaction forces and the inner pressure of the cask cavity, the detailed three dimensional FEM models are developed

  5. Safety Analysis of Dual Purpose Metal Cask Subjected to Impulsive Loads due to Aircraft Engine Crash

    Science.gov (United States)

    Shirai, Koji; Namba, Kosuke; Saegusa, Toshiari

    In Japan, the first Interim Storage Facility of spent nuclear fuel away from reactor site is being planned to start its commercial operation around 2010, in use of dual-purpose metal cask in the northern part of Main Japan Island. Business License Examination for safety design approval has started since March, 2007. To demonstrate the more scientific and rational performance of safety regulation activities on each phase for the first license procedure, CREPEI has executed demonstration tests with full scale casks, such as drop tests onto real targets without impact limiters(1) and seismic tests subjected to strong earthquake motions(2). Moreover, it is important to develop the knowledge for the inherent security of metal casks under extreme mechanical-impact conditions, especially for increasing interest since the terrorist attacks from 11th September 2001(3)-(6). This paper presents dynamic mechanical behavior of the metal cask lid closure system caused by direct aircraft engine crash and describes calculated results (especially, leak tightness based on relative dynamic displacements between metallic seals). Firstly, the local penetration damage of the interim storage facility building by a big passenger aircraft engine crash (diameter 2.7m, length 4.3m, weight 4.4ton, impact velocity 90m/s) has been examined. The reduced velocity is calculated by the local damage formula for concrete structure with its thickness of 70cm. The load vs. time function for this reduced velocity (60m/s) is estimated by the impact analysis using Finite Element code LS-DYNA with the full scale engine model onto a hypothetically rigid target. Secondly, as the most critical scenarios for the metal cask, two impact scenarios (horizontal impact hitting the cask and vertical impact onto the lid metallic seal system) are chosen. To consider the geometry of all bolts for two lids, the gasket reaction forces and the inner pressure of the cask cavity, the detailed three dimensional FEM models are

  6. Readmissions for Selected Infections Due to Medical Care: Expanding the Definition of a Patient Safety Indicator

    National Research Council Canada - National Science Library

    Gallagher, Brian; Cen, Liyi; Hannan, Edward L

    2005-01-01

    Objective: Evaluate the Agency for Healthcare Research and Quality's Patient Safety Indicator that identifies patients with selected infections that result from medical care during hospital inpatient treatment...

  7. Refining margins and prospects

    International Nuclear Information System (INIS)

    Baudouin, C.; Favennec, J.P.

    1997-01-01

    Refining margins throughout the world have remained low in 1996. In Europe, in spite of an improvement, particularly during the last few weeks, they are still not high enough to finance new investments. Although the demand for petroleum products is increasing, experts are still sceptical about any rapid recovery due to prevailing overcapacity and to continuing capacity growth. After a historical review of margins and an analysis of margins by regions, we analyse refining over-capacities in Europe and the unbalances between production and demand. Then we discuss the current situation concerning barriers to the rationalization, agreements between oil companies, and the consequences on the future of refining capacities and margins. (author)

  8. Guidelines for Safety Evaluation of a Potential for PWR Steam Generator Tube Failure due to Fluid elastic Instability

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jong Chull; Do, Kyu Sik; Sheen, Cheol [Nuclear System Evaluation Dept., Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2013-05-15

    It was found that both SG tube rupture events occurred at North Anna Unit 1 in 1987 and at Mihama Unit 2 in 1991 were caused by a high cycle fatigue due to fluid elastic instability. Therefore, with regard to nuclear safety it is important to design the SG properly in a conservative manner so that the potential for SG U-tube failures due to fluid elastic instability can be minimized. This article provides guidelines for assessing the potential for SG U-tube damage due to fluid elastic instability. This article described guidelines for safety evaluation of a potential for PWR steam generator tube failure due to fluid elastic instability. The guidelines address the requirements for realistically performing the SG thermal-hydraulic analysis and the modal analysis of tubes as well as the criteria for conservatively determining the added mass, the damping ratio and the fluid elastic instability coefficient. The guidelines can be used to predict the potential SG tubes which are susceptible to failure due to fluid elastic instability at operating nuclear power plants and also to evaluate the safety and structural integrity of new SG designs at the licensing review stage. Failure of a pressurized water reactor (PWR) steam generator (SG) tube leads to a leakage of contaminated primary coolant to the secondary system, which has serious safety implications such as the potential for direct release of radioactive fission products to the environment and the loss of coolant. Excessive tube vibration excited by dynamic forces of internal or external fluid flow is called flow-induced vibration (FIV). Among the FIV mechanisms, the so-called fluid elastic instability of SG tubes in cross flow is the most important safety issue in the design of SGs because it may cause severe tube failure in a very short time.

  9. Methodology for assessment of safety risk due to potential accidents in US gaseous diffusion plants

    International Nuclear Information System (INIS)

    Turner, J.H.; O'Kain, D.U.

    1991-01-01

    Gaseous diffusion plants that operate in the United States represent a unique combination of nuclear and chemical hazards. Assessing and controlling the health, safety, and environmental risks that can result from natural phenomena events, process upset conditions, and operator errors require a unique methodology. Such a methodology has been developed for the diffusion plants and is being utilized to assess and control the risk of operating the plants. A summary of the methodology developed to assess the unique safety risks at the US gaseous diffusion plants is presented in this paper

  10. Generic analyses for evaluation of low Charpy upper-shelf energy effects on safety margins against fracture of reactor pressure vessel materials

    International Nuclear Information System (INIS)

    Dickson, T.L.

    1993-07-01

    Appendix G to 10 CFR Part 50 requires that reactor pressure vessel beltline material maintain Charpy upper-shelf energies of no less than 50 ft-lb during the plant operating life, unless it is demonstrated in a manner approved by the Nuclear Regulatory Commission (NRC), that lower values of Charpy upper-shelf energy provide margins of safety against fracture equivalent to those in Appendix G to Section XI of the ASME Code. Analyses based on acceptance criteria and analysis methods adopted in the ASME Code Case N-512 are described herein. Additional information on material properties was provided by the NRC, Office of Nuclear Regulatory Research, Materials Engineering Branch. These cases, specified by the NRC, represent generic applications to boiling water reactor and pressurized water reactor vessels. This report is designated as HSST Report No. 140

  11. Investigation of safety margin for turbine generator foundation affected by Alkali Silica reaction based on non-linear structure analysis

    International Nuclear Information System (INIS)

    Shimizu, H.; Asai, Y.; Hosokawa, T.; Sekimoto, H.; Sato, K.; Oshima, R.; Takiguchi, K.; Masuda, Y.; Nishiguchi, I.

    2005-01-01

    A turbine generator foundation is a reinforced concrete structure having a table deck and columns to support equipments. After operation of the plant, the expansion of the table deck in turbine longitudinal axis has been observed. By investigation of concrete material properties, it was found that the expansion has been caused by alkali-silica reaction. This study has been performed to evaluate the safety allowance of strength capacity of the turbine generator foundation by nonlinear analysis using beam element model with elongation, rebar strain and material properties data which have been measured for almost 30 years in actual foundation. (authors)

  12. Xylem hydraulic safety margins in woody plants: coordination of stomatal control of xylem tension with hydraulic capacitance

    Science.gov (United States)

    Frederick C. Meinzer; Daniel M. Johnson; Barbara Lachenbruch; Katherine A. McCulloh; David R. Woodruff

    2009-01-01

    The xylem pressure inducing 50% loss of hydraulic conductivity due to embolism (P50) is widely used for comparisons of xylem vulnerability among species and across aridity gradients. However, despite its utility as an index of resistance to catastrophic xylem failure under extreme drought, P50 may have no special...

  13. ACED devices and SECAF supports for the control of structure, pipe network and equipment behaviour at seismic movements in order to enhance the safety margin

    International Nuclear Information System (INIS)

    Serban, Viorel; Prisecaru, I.; Cretu, D.; Moldoveanu, T.

    2002-01-01

    In order to enhance the safety margin of structure, pipe networks and equipment associated to the existing NPPs, the classic consolidation solutions are very expensive and many times, impossible to be implemented. Structures, pipe networks, systems and equipment have geometries imposed by the basic construction requirements, operating and safety requirements and their modifications is not always possible. In order to enhance the strength capacity of (new or old) structures, systems and equipment mechanical devices with controlled elasticity and damping (ACED) have been designed, constructed and experimented. These devices are capable to support very large static loads over which dynamic loads (shock, vibration and seismic movements) overlap (which are damped). To increase the strength capacity of (new or existing) pipe networks and equipment connecting with pipes, SECAF supports that allow displacements from thermal expansions with low reaction force have been designed, constructed and experimented. SECAF supports are capable elastically to take permanent loads over which shocks, vibrations and seismic movements (which are damp) overlap. ACED devices and SECAF supports can be used to rehabilitate the existing NPPs with law financial costs and an increase of their strength capacity up to 100% under seismic movements, shocks and vibrations. ACED devices and SECAF supports do not require maintenance, are not affected by presence of a radiation field and their estimated service-life is similar to the NPPs

  14. Enhanced safety margins during wet transport of irradiated fuel by catalytic recombination of radiolysis hydrogen and oxygen

    International Nuclear Information System (INIS)

    Spencer, J.T.; Bankhead, M.; Hodge, N.A.

    2004-01-01

    BNFL has developed and tested a new method for use in wet transport of irradiated fuel. The method uses a catalyst to recombine the hydrogen and oxygen produced from radiolysis. The catalyst is installed in the nitrogen ullage gas region. It has twin benefits as it eliminates a gas mixture that could, in principle, exceed the safe target levels set to ensure safety during Transport, and it also reduces overall gas pressure. Pure water radiolysis predictions, from experiment and theory, indicate very low levels of hydrogen and oxygen generation. BNFL's historic experience is that in some transport packages it is possible to produce higher levels of hydrogen and oxygen. This drives the need to improve on our existing ullage gas remediation technology. Our studies of the radiolysis science and our flask data suggest it is the interaction of the liquors and material surfaces that is giving rise to the enhanced levels of hydrogen and/or oxygen. This technical paper demonstrates the performance of the recombiner catalyst under normal and extreme conditions of transport. The paper will present experimental data that shows the recombiner catalyst working to manage the hydrogen and oxygen levels

  15. Safety requirements for buildings under induced earthquakes due to gas extraction

    NARCIS (Netherlands)

    Steenbergen, R.D.J.M.; Vrouwenvelder, A.C.W.M.

    2017-01-01

    In the Dutch province of Groningen over the last year shallow earthquakes are induced due to large scale gas extraction from the gas field at 3 km depth. The induced earthquakes differ from the better known tectonic earthquakes all over the world, caused by movement of the earth at large depths. The

  16. Marginal Matter

    Science.gov (United States)

    van Hecke, Martin

    2013-03-01

    All around us, things are falling apart. The foam on our cappuccinos appears solid, but gentle stirring irreversibly changes its shape. Skin, a biological fiber network, is firm when you pinch it, but soft under light touch. Sand mimics a solid when we walk on the beach but a liquid when we pour it out of our shoes. Crucially, a marginal point separates the rigid or jammed state from the mechanical vacuum (freely flowing) state - at their marginal points, soft materials are neither solid nor liquid. Here I will show how the marginal point gives birth to a third sector of soft matter physics: intrinsically nonlinear mechanics. I will illustrate this with shock waves in weakly compressed granular media, the nonlinear rheology of foams, and the nonlinear mechanics of weakly connected elastic networks.

  17. Thermal-Hydraulic Effects of Stud Shape and Size on the Safety Margin of Core Catcher System

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kyusang; Son, Hong Hyun; Jeong, Uiju; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

    2015-10-15

    effect of studs on the performance of boiling heat transfer is significant. In this work, an experimental study has been conducted to investigate the effects of stud shape and size on the pool boiling CHF of saturated water under the atmospheric pressure. The major conclusions from this study are summarized as follows. (1). The experimental result confirmed that the installation of the stud influenced the CHF value due thermal-hydraulic restriction. With the presence of studs, the CHF value was measured lower than the bare specimen up and the reduction ranged from 18% to 55% depending on the stud shape and size. (2). It was observed that CHF data generally decreases as the stud size becomes larger. Especially, when the size of the studs was 25 mm, the CHF value drastically decreased in all studs' shape.

  18. Thermal-Hydraulic Effects of Stud Shape and Size on the Safety Margin of Core Catcher System

    International Nuclear Information System (INIS)

    Song, Kyusang; Son, Hong Hyun; Jeong, Uiju; Kim, Sung Joong

    2015-01-01

    effect of studs on the performance of boiling heat transfer is significant. In this work, an experimental study has been conducted to investigate the effects of stud shape and size on the pool boiling CHF of saturated water under the atmospheric pressure. The major conclusions from this study are summarized as follows. (1). The experimental result confirmed that the installation of the stud influenced the CHF value due thermal-hydraulic restriction. With the presence of studs, the CHF value was measured lower than the bare specimen up and the reduction ranged from 18% to 55% depending on the stud shape and size. (2). It was observed that CHF data generally decreases as the stud size becomes larger. Especially, when the size of the studs was 25 mm, the CHF value drastically decreased in all studs' shape

  19. Determination of safety margins for creep loaded primary circuit components in case of loss of pressure accidents of a HTR plant (SR 383)

    International Nuclear Information System (INIS)

    Breitbach, G.; Ahmed, K.; Over, H.; Schubert, F.; Nickel, H.

    1991-10-01

    The wall thickness of tubes in high temperature plants must be limited in such a way that pressure differences can not produce unadmissible deformations. For HTR (PNP-Plant) the postulated loss of secondary pressure is one of the considered accidents. In that case the tubes of the heat exchangers are loaded by the outher pressure of the primary coolant. So the risk of a creep collapse is given. The report is related to experimental and theoretical work for the creep collapse phenomena. HTR relevant tube geometries of the high temperature alloys NiCr22Co12Mo (INCONEL 617) and X10NiCrAlTi 32 20 (INCOLOY 800) were tested at temperatures of 900 and 950deg C and outer pressure loads in the range 40 bars. The experimental results are compared with theoretically computed values and discussed. The problem of safety margin is treated. Further, simplified procedures are developed for the estimation of the collapse time. (orig.) [de

  20. Radiological safety and environmental implications in beach mineral industry due to naturally occurring radioactive materials

    International Nuclear Information System (INIS)

    Pillai, P.M.B.; Haridasan, P.P.; Maniyan, C.G.; Khan, A.H.

    2002-01-01

    The presence of monazite (primary ore of Thorium) along with ilmenite and other minerals in the beach sand deposits of coastal regions of South India has made some of these coastal areas prominent among Natural High Background Radiation Areas (NHBRA) in the world. The beach mineral industries are situated in populated areas in these NHBRAs. The radiation background prevailing in these areas due to the presence of the Naturally Occurring Radioactive Materials (NORM) Thorium with traces of Uranium and their decay products had been found to result in estimated percaput annual external exposures ranging from 3 to 25 mSv to the population at NHBRA depending on the monazite content of the soil in the area. The internal exposures estimated are of the order of 1 to 2 mSv per year. The mining of minerals and refilling of the mined out areas with mineral free sand and rehabilitation of the area is found to reduce the external radiation fields by a factor of 3. The notional environmental external radiation exposures to the population occupying this modified NHBRA also reduce correspondingly. (author)

  1. Refining margins: recent trends

    International Nuclear Information System (INIS)

    Baudoin, C.; Favennec, J.P.

    1999-01-01

    Despite a business environment that was globally mediocre due primarily to the Asian crisis and to a mild winter in the northern hemisphere, the signs of improvement noted in the refining activity in 1996 were borne out in 1997. But the situation is not yet satisfactory in this sector: the low return on invested capital and the financing of environmental protection expenditure are giving cause for concern. In 1998, the drop in crude oil prices and the concomitant fall in petroleum product prices was ultimately rather favorable to margins. Two elements tended to put a damper on this relative optimism. First of all, margins continue to be extremely volatile and, secondly, the worsening of the economic and financial crisis observed during the summer made for a sharp decline in margins in all geographic regions, especially Asia. Since the beginning of 1999, refining margins are weak and utilization rates of refining capacities have decreased. (authors)

  2. Oriented growth due to topotactic replacement of antigorite by olivine as a mechanism for the formation of B-type olivine CPO in convergent margins

    Science.gov (United States)

    Nagaya, T.; Wallis, S.; Kobayashi, H.; Michibayashi, K.; Mizukami, T.

    2012-12-01

    B-type olivine (Ol) CPO patterns are characterized by an a-axis concentration parallel to the intermediate principle axis of strain and have been proposed by many workers as the cause of seismic anisotropy in the mantle wedge of subduction zones that shows the fast direction perpendicular to the plate movement direction. Experimental work has shown that B-type Ol CPO can form by dislocation creep at relatively high stresses and in the presence of water. Natural examples of B-type Ol CPO have also been reported, but there are several discrepancies with the experimental results. 1) Some natural B-type CPO formed at relatively high temperatures and low stress outside the ranges predicted by experiments. 2) Natural examples lack evidence for the c-slip expected for the formation of B-type Ol CPO by dislocation creep. 3) The high shear stresses expected along subduction boundaries promote the formation of B-type Ol CPO, but these regions are also expected to be associated with the formation of serpentine minerals and even relatively small amounts prevent strong CPO patterns from forming because of grain-boundary sliding occurring between Ol and serpentine. We show B-type Ol CPO can form as a result of static topotactic growth of olivine after high-temperature breakdown of antigorite (Atg) schist. In the Happo-One region of the Hida Marginal belt, Japan, dehydration of foliated Atg produces non-deformed secondary Ol formed in veins or patches and peridotite-hornfels where the conversion is complete.The CPO of non-deformed Ol in veins and in the hornfels shows a strong B-type fabric. The veins show consistent Ol CPO irrespective of the vein orientation, implying the CPO is not related to the vein opening direction. The CPO of Atg bordering the vein Ol shows a strong concentration of c-axes at a high angle to the foliation and a strong alignment of b-axes parallel to the lineation. Numerous recent studies have shown this type of Atg CPO is the most widespread in the

  3. Margin improvement initiatives: realistic approaches

    Energy Technology Data Exchange (ETDEWEB)

    Chan, P.K.; Paquette, S. [Royal Military College of Canada, Chemistry and Chemical Engineering Dept., Kingston, ON (Canada); Cunning, T.A. [Department of National Defence, Ottawa, ON (Canada); French, C.; Bonin, H.W. [Royal Military College of Canada, Chemistry and Chemical Engineering Dept., Kingston, ON (Canada); Pandey, M. [Univ. of Waterloo, Waterloo, ON (Canada); Murchie, M. [Cameco Fuel Manufacturing, Port Hope, ON (Canada)

    2014-07-01

    With reactor core aging, safety margins are particularly tight. Two realistic and practical approaches are proposed here to recover margins. The first project is related to the use of a small amount of neutron absorbers in CANDU Natural Uranium (NU) fuel bundles. Preliminary results indicate that the fuelling transient and subsequent reactivity peak can be lowered to improve the reactor's operating margins, with minimal impact on burnup when less than 1000 mg of absorbers is added to a fuel bundle. The second project involves the statistical analysis of fuel manufacturing data to demonstrate safety margins. Probability distributions are fitted to actual fuel manufacturing datasets provided by Cameco Fuel Manufacturing, Inc. They are used to generate input for ELESTRES and ELOCA. It is found that the fuel response distributions are far below industrial failure limits, implying that margin exists in the current fuel design. (author)

  4. 32-Phosphorus for bone pain palliation due to bone metastases, its safety and efficacy in patients with advanced cancer

    International Nuclear Information System (INIS)

    Fettich, J.; Nair, G.; Padky, A.K.; Stare, J.; Nair, N.; Moralles, R.; Riccabona, G.; Tanumihardia, M.

    2001-01-01

    Bone pain due to bony metastases can seriously affect a patient's quality of life. External irradiation, narcotic drugs and polyphosphates may cause important side effects or are expensive, therefore in many patients radionuclide treatment using a single dose of beta emitting bone seeking radiopharmaceuticals has become widely accepted. Except 32-Phosphorus (32-P) all of them are expensive and difficult to obtain in certain countries. The aim of the study was to evaluate safety and efficacy of 32-P for palliation of bone pain due to bony metastases by comparing it to 89-Strontium (89-Sr), the most commonly used radiopharmaceutical for bone pain palliation in the framework of a prospective IAEA co-ordinated multicenter study. A very strict protocol for unified patient inclusion and follow up was used. 93 cancer patients with osteoblastic bony metastases were included into the study, 48 were treated by 89-Sr (150 MBq) and 45 by 32-P (450 MBq). Pain score, analgesic consumption, quality of life, and indices of bone marrow depression were monitored 2 weeks pre- and up to 4 months post treatment. Favourable response to treatment was recorded in 75% of the patients treated with 89-Sr and in 60% of those treated with 32-P (p=0,122). There was no significant difference between the duration of favourable effect for both radiopharmaceuticals. Moderate decrease of white blood cell (WBC) and platelet counts, and haemoglobin (Hb) levels was detected more often in the 32-P treated group. Although 32-P appears to be more toxic, no toxic effects requiring specific treatment were seen in either group. Due to its comparable efficacy and safety, general availability and low cost its more widespread use should be encouraged to increase quality of life and reduce cost of medical care of patients with intractable bone pain due to cancer metastases. (author)

  5. Marginal kidney donor

    Directory of Open Access Journals (Sweden)

    Ganesh Gopalakrishnan

    2007-01-01

    Full Text Available Renal transplantation is the treatment of choice for a medically eligible patient with end stage renal disease. The number of renal transplants has increased rapidly over the last two decades. However, the demand for organs has increased even more. This disparity between the availability of organs and waitlisted patients for transplants has forced many transplant centers across the world to use marginal kidneys and donors. We performed a Medline search to establish the current status of marginal kidney donors in the world. Transplant programs using marginal deceased renal grafts is well established. The focus is now on efforts to improve their results. Utilization of non-heart-beating donors is still in a plateau phase and comprises a minor percentage of deceased donations. The main concern is primary non-function of the renal graft apart from legal and ethical issues. Transplants with living donors outnumbered cadaveric transplants at many centers in the last decade. There has been an increased use of marginal living kidney donors with some acceptable medical risks. Our primary concern is the safety of the living donor. There is not enough scientific data available to quantify the risks involved for such donation. The definition of marginal living donor is still not clear and there are no uniform recommendations. The decision must be tailored to each donor who in turn should be actively involved at all levels of the decision-making process. In the current circumstances, our responsibility is very crucial in making decisions for either accepting or rejecting a marginal living donor.

  6. Safety of greenlight photoselective vaporisation of prostate in lower urinary tract symptoms due to benign prostatic hyperplasia in patients using anticoagulants due to cardiovascular comorbidities

    Directory of Open Access Journals (Sweden)

    Basri Cakiroglu

    2015-07-01

    Full Text Available Lasers have been used in the management of benign prostatic hyperplasia for the last two decades. To be comparable, they should reduce or avoid the immediate and long-term complications of transurethral resection of the prostate (TURP or open prostatectomy (OP, especially bleeding and need for blood transfusion. Although Holmium laser treatment of the prostate was compared frequently in terms of cardiovascular safety with TURP or OP, photoselective vaporisation of the prostate (PVP was not largely evaluated. In this article we analyzed the current literature to see if there is convincing data to support the observation of some authors that use of PVP is associated with increased safety in patients on anticoagulants with cardiovascular comorbidities. With this purpose a Medline search between January 2004 to March 2013 was performed using evidence obtained from randomised trials, well-designed controlled studies without randomisation, individual cohort studies, individual case control studies and case reports Results: In the last 10 years, several case-control and cohort studies have demonstrated the efficacy of PVP as well as its safety in patients with cardiovascular comorbidities using anticoagulants. The results confirmed the overall lower perioperative and postoperative morbidity of PVP, whereas the efficacy was comparable to TURP in the short term, despite a higher reoperation rate. Conclusion: Although it is still developing, PVP with KTP or LBO seems to be a promising alternative to both TURP and OP in terms of cardiovascular safety and in patients using anticoagulants.

  7. Seismic Margin of 500MWe PFBR Beyond Safe Shutdown Earthquake

    International Nuclear Information System (INIS)

    Sajish, S.D.; Chellapandi, P.; Chetal, S.C.

    2012-01-01

    Summary: • Seismic design aspects of safety related systems and components of PFBR is discussed with a focus on reactor assembly components. • PFBR is situated in a low seismic area with a peak ground acceleration value of 0.156 g. • The design basis ground motion parameters for the seismic design are evaluated by deterministic method and confirmed by probabilistic seismic hazard analysis. • Review of the seismic design of various safety related systems and components indicate that margin is available to meet any demand due to an earthquake beyond SSE. • Reactor assembly vessels are the most critical components w.r.t seismic loading. • Minimum safety margin is 1.41 for plastic deformation and 1.46 against buckling. • From the preliminary investigation we come to the conclusion that PFBR can withstand an earthquake up to 0.22 g without violating any safety limits. • Additional margin can be estimated by detailed fragility analysis and seismic margin assessment methods

  8. Safety

    International Nuclear Information System (INIS)

    1998-01-01

    A brief account of activities carried out by the Nuclear power plants Jaslovske Bohunice in 1997 is presented. These activities are reported under the headings: (1) Nuclear safety; (2) Industrial and health safety; (3) Radiation safety; and Fire protection

  9. Operating without a Safety Net: Gay Male Adolescents and Emerging Adults' Experiences of Marginalization and Migration, and Implications for Theory of Syndemic Production of Health Disparities

    Science.gov (United States)

    Bruce, Douglas; Harper, Gary W.

    2011-01-01

    Health disparities among gay men (HIV, substance use, depression) have been described as a mutually occurring "syndemic" that is socially produced through two overarching dynamics: marginalization and migration. Although the syndemic theory proposes a developmental trajectory, it has been largely based on epidemiological studies of adult gay men…

  10. SAFETY

    CERN Multimedia

    M. Plagge, C. Schaefer and N. Dupont

    2013-01-01

    Fire Safety – Essential for a particle detector The CMS detector is a marvel of high technology, one of the most precise particle measurement devices we have built until now. Of course it has to be protected from external and internal incidents like the ones that can occur from fires. Due to the fire load, the permanent availability of oxygen and the presence of various ignition sources mostly based on electricity this has to be addressed. Starting from the beam pipe towards the magnet coil, the detector is protected by flooding it with pure gaseous nitrogen during operation. The outer shell of CMS, namely the yoke and the muon chambers are then covered by an emergency inertion system also based on nitrogen. To ensure maximum fire safety, all materials used comply with the CERN regulations IS 23 and IS 41 with only a few exceptions. Every piece of the 30-tonne polyethylene shielding is high-density material, borated, boxed within steel and coated with intumescent (a paint that creates a thick co...

  11. Margins related to equipment design

    International Nuclear Information System (INIS)

    Devos, J.

    1994-01-01

    Safety margins related to design of reactor equipment are defined according to safety regulations. Advanced best estimate methods are proposed including some examples which were computed and compared to experimental results. Best estimate methods require greater computation effort and more material data but give better variable accuracy and need careful experimental validation. Simplified methods compared to the previous are less sensitive to material data, sometimes are more accurate but very long to elaborate

  12. Caught in the competitive crossfire: safety-net providers balance margin and mission in a profit-driven health care market.

    Science.gov (United States)

    Cunningham, Peter J; Bazzoli, Gloria J; Katz, Aaron

    2008-01-01

    This paper describes how intensifying competitive pressures in the health system are simultaneously driving increased demand for safety-net care and taxing safety-net providers' ability to maintain the mission of serving all, regardless of ability to pay. Although safety-net providers adapted to previous challenges arising from managed care, health system pressures have been more intense and more generalized across different sectors in recent years than in the past. Providers are adopting some of the same strategies being used in the private sector to attract higher-paying patients and changing their "image" as a safety-net provider.

  13. Due diligence

    International Nuclear Information System (INIS)

    Sanghera, G.S.

    1999-01-01

    The Occupational Health and Safety (OHS) Act requires that every employer shall ensure the health and safety of workers in the workplace. Issues regarding the practices at workplaces and how they should reflect the standards of due diligence were discussed. Due diligence was described as being the need for employers to identify hazards in the workplace and to take active steps to prevent workers from potentially dangerous incidents. The paper discussed various aspects of due diligence including policy, training, procedures, measurement and enforcement. The consequences of contravening the OHS Act were also described

  14. Evaluation of the effectiveness and safety of glucocorticoids intravitreal implant therapy in macular edema due to retinal vein occlusion

    Directory of Open Access Journals (Sweden)

    Michalska-Małecka K

    2016-05-01

    Full Text Available Katarzyna Michalska-Małecka,1,2 Aneta Gaborek,2 Mariusz Nowak,3 Tomasz Halat,4 Mariola Pawłowska,2 Dorota Śpiewak2 1Department of Ophthalmology, School of Medicine in Katowice, Medical University of Silesia, Katowice, 2University Center of Ophthalmology and Oncology, Independent Public Clinical Hospital, Medical University of Silesia, Katowice, 3Pathophysiology Division, Department of Pathophysiology and Endocrinology, Medical University of Silesia, School of Medicine with Division of Density, Zabrze, 4Education and Medical Simulation Center, Medical University of Silesia, Katowice, Poland Abstract: The purpose of this study was to evaluate the impact of intravitreal dexamethasone implant (Ozurdex on macular morphology and functions in eyes with macular edema (ME secondary to retinal vein occlusion. Efficacy outcomes of the treatment were best-corrected visual acuity (BCVA and central retinal thickness (CRT. Safety outcomes were intraocular pressure and cornea endothelial cell density. The study was conducted by the prospective analysis on 36 patients (17 women and 19 men aged 28–77 years (the average age was 58±15 years treated with the injection of dexamethasone implant because of the persistent ME at the Department of Ophthalmology and Ophthalmology Outpatient Clinic of the University Centre of Ophthalmology and Oncology in Katowice. The studied group included 16 patients with central retinal vein occlusion (16 eyes, and 20 patients with branch retinal vein occlusion (20 eyes. We found a significant increase of BCVA after first, second, and third month of treatment. Six months after the treatment, BCVA decreased, although not significantly compared with the value obtained in the third month. Two months after the intravitreal implantation of dexamethasone delivery system, CRT was 338±163 µm and was significantly lower compared with pretreatment value. Between third and sixth month after the treatment, we found insignificant increase of

  15. SAFETY

    CERN Multimedia

    Niels Dupont

    2013-01-01

    CERN Safety rules and Radiation Protection at CMS The CERN Safety rules are defined by the Occupational Health & Safety and Environmental Protection Unit (HSE Unit), CERN’s institutional authority and central Safety organ attached to the Director General. In particular the Radiation Protection group (DGS-RP1) ensures that personnel on the CERN sites and the public are protected from potentially harmful effects of ionising radiation linked to CERN activities. The RP Group fulfils its mandate in collaboration with the CERN departments owning or operating sources of ionising radiation and having the responsibility for Radiation Safety of these sources. The specific responsibilities concerning "Radiation Safety" and "Radiation Protection" are delegated as follows: Radiation Safety is the responsibility of every CERN Department owning radiation sources or using radiation sources put at its disposition. These Departments are in charge of implementing the requi...

  16. Craniocaudal Safety Margin Calculation Based on Interfractional Changes in Tumor Motion in Lung SBRT Assessed With an EPID in Cine Mode

    International Nuclear Information System (INIS)

    Ueda, Yoshihiro; Miyazaki, Masayoshi; Nishiyama, Kinji; Suzuki, Osamu; Tsujii, Katsutomo; Miyagi, Ken

    2012-01-01

    Purpose: To evaluate setup error and interfractional changes in tumor motion magnitude using an electric portal imaging device in cine mode (EPID cine) during the course of stereotactic body radiation therapy (SBRT) for non–small-cell lung cancer (NSCLC) and to calculate margins to compensate for these variations. Materials and Methods: Subjects were 28 patients with Stage I NSCLC who underwent SBRT. Respiratory-correlated four-dimensional computed tomography (4D-CT) at simulation was binned into 10 respiratory phases, which provided average intensity projection CT data sets (AIP). On 4D-CT, peak-to-peak motion of the tumor (M-4DCT) in the craniocaudal direction was assessed and the tumor center (mean tumor position [MTP]) of the AIP (MTP-4DCT) was determined. At treatment, the tumor on cone beam CT was registered to that on AIP for patient setup. During three sessions of irradiation, peak-to-peak motion of the tumor (M-cine) and the mean tumor position (MTP-cine) were obtained using EPID cine and in-house software. Based on changes in tumor motion magnitude (∆M) and patient setup error (∆MTP), defined as differences between M-4DCT and M-cine and between MTP-4DCT and MTP-cine, a margin to compensate for these variations was calculated with Stroom’s formula. Results: The means (±standard deviation: SD) of M-4DCT and M-cine were 3.1 (±3.4) and 4.0 (±3.6) mm, respectively. The means (±SD) of ∆M and ∆MTP were 0.9 (±1.3) and 0.2 (±2.4) mm, respectively. Internal target volume-planning target volume (ITV-PTV) margins to compensate for ∆M, ∆MTP, and both combined were 3.7, 5.2, and 6.4 mm, respectively. Conclusion: EPID cine is a useful modality for assessing interfractional variations of tumor motion. The ITV-PTV margins to compensate for these variations can be calculated.

  17. Quantification of design margins and safety factors based on the prediction uncertainty in tritium production rate from fusion integral experiments of the USDOE/JAERI collaborative program on fusion blanket neutronics

    International Nuclear Information System (INIS)

    Youssef, M.Z.; Konno, C.; Maekawa, F.; Ikeda, Y.; Kosako, K.; Nakagawa, M.; Mori, T.; Maekawa, H.

    1995-01-01

    Several fusion integral experiments were performed within a collaboration between the USA and Japan on fusion breeder neutronics aimed at verifying the prediction accuracy of key neutronics parameters in a fusion reactor blanket based on current neutron transport codes and basic nuclear databases. The focus has been on the tritium production rate (TRP) as an important design parameter to resolve the issue of tritium self-sufficiency in a fusion reactor. In this paper, the calculational and experimental uncertainties (errors) in local TPR in each experiment performed i were interpolated and propagated to estimate the prediction uncertainty u i in the line-integrated TPR and its standard deviation σ i . The measured data are based on Li-glass and NE213 detectors. From the quantities u i and σ i , normalized density functions (NDFs) were constructed, considering all the experiments and their associated analyses performed independently by the UCLA and JAERI. Several statistical parameters were derived, including the mean prediction uncertainties u and the possible spread ±σ u around them. Design margins and safety factors were derived from these NDFs. Distinction was made between the results obtained by UCLA and JAERI and between calculational results based on the discrete ordinates and Monte Carlo methods. The prediction uncertainties, their standard deviations and the design margins and safety factors were derived for the line-integrated TPR from Li-6 T 6 , and Li-7 T 7 . These parameters were used to estimate the corresponding uncertainties and safety factor for the line-integrated TPR from natural lithium T n . (orig.)

  18. Safety

    International Nuclear Information System (INIS)

    2001-01-01

    This annual report of the Senior Inspector for the Nuclear Safety, analyses the nuclear safety at EDF for the year 1999 and proposes twelve subjects of consideration to progress. Five technical documents are also provided and discussed concerning the nuclear power plants maintenance and safety (thermal fatigue, vibration fatigue, assisted control and instrumentation of the N4 bearing, 1300 MW reactors containment and time of life of power plants). (A.L.B.)

  19. Approach to uncertainty evaluation for safety analysis

    International Nuclear Information System (INIS)

    Ogura, Katsunori

    2005-01-01

    Nuclear power plant safety used to be verified and confirmed through accident simulations using computer codes generally because it is very difficult to perform integrated experiments or tests for the verification and validation of the plant safety due to radioactive consequence, cost, and scaling to the actual plant. Traditionally the plant safety had been secured owing to the sufficient safety margin through the conservative assumptions and models to be applied to those simulations. Meanwhile the best-estimate analysis based on the realistic assumptions and models in support of the accumulated insights could be performed recently, inducing the reduction of safety margin in the analysis results and the increase of necessity to evaluate the reliability or uncertainty of the analysis results. This paper introduces an approach to evaluate the uncertainty of accident simulation and its results. (Note: This research had been done not in the Japan Nuclear Energy Safety Organization but in the Tokyo Institute of Technology.) (author)

  20. Quantifying reactor safety margins: Application of code scaling, applicability, and uncertainty evaluation methodology to a large-break, loss-of-coolant accident

    International Nuclear Information System (INIS)

    Boyack, B.; Duffey, R.; Wilson, G.; Griffith, P.; Lellouche, G.; Levy, S.; Rohatgi, U.; Wulff, W.; Zuber, N.

    1989-12-01

    The US Nuclear Regulatory Commission (NRC) has issued a revised rule for loss-of-coolant accident/emergency core cooling system (ECCS) analysis of light water reactors to allow the use of best-estimate computer codes in safety analysis as an option. A key feature of this option requires the licensee to quantify the uncertainty of the calculations and include that uncertainty when comparing the calculated results with acceptance limits provided in 10 CFR Part 50. To support the revised ECCS rule and illustrate its application, the NRC and its contractors and consultants have developed and demonstrated an uncertainty evaluation methodology called code scaling, applicability, and uncertainty (CSAU). The CSAU methodology and an example application described in this report demonstrate that uncertainties in complex phenomena can be quantified. The methodology is structured, traceable, and practical, as is needed in the regulatory arena. The methodology is systematic and comprehensive as it addresses and integrates the scenario, experiments, code, and plant to resolve questions concerned with: (a) code capability to scale-up processes from test facility to full-scale nuclear power plants; (b) code applicability to safety studies of a postulated accident scenario in a specified nuclear power plant; and (c) quantifying uncertainties of calculated results. 127 refs., 55 figs., 40 tabs

  1. Safety Evaluation for IHTS Integrity due to the Steam Generator Sodium-Water Reaction Event in the PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sang-Jun; Lee, Kwi Lim; Ha, Kwi-Seok; Lee, Seung Won; Jeong, Taekyeong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    In this paper, the integrity of the IHTS and SG by the SWR event are evaluated using the SWAAMII code. A sodium has a chemical characteristics to rigorously react the water or steam and produce the high pressure waves and high temperature reaction heat. It has an excellent characteristics as a reactor coolant. But, there is an event to be considered in the sodium cooled fast reactor design. The Sodium-Water Reaction (SWR) event can be occurred by the water or steam leaks due to the break of the steam generator tubes. The propagated high pressure waves threathen the structural integrity of the affected Intermediate Heat Transport System (IHTS) and steam generator. If the IHTS pipes are failed, the sodium of the IHTS can be released to the containment building. To the peak pressure point of view, it is performed to evaluate the integrity of the major components due to the SWR event in the SG. The generated peak pressures due to the five SG tubes simultaneous break event are within the range of the design pressure for the SG, IHX and IHTS including the related pipes.

  2. The drone as an additional risk factor due to conditions not provided for in radiological safety at major events

    International Nuclear Information System (INIS)

    Oliveira, Gilberto de Jesus

    2015-01-01

    Major international events are potential targets of terrorist actions, seeking instant publicity that events of this magnitude provide, with the intention of causing terror and disseminate its power to a large number of people worldwide. In this context, the critical analysis of additional risk factor linked to procedures and protocols adopted on radiation safety is important. The possibility of unforeseen situations of risk, especially those resulting from the current global technological development, is a fact. Radioactive material can be used in this type of terrorism in a wide range of devices and illicit trafficking of this material is a reality that worries the International Atomic Energy Agency. In the current technological development scenario of the world, the potential occurrence of terrorist acts using drones combined with radioactive material dispersal devices, is real. The recent history of drones incidents presents cases where, despite not having been necessarily terrorist motivation, their circumstances and characteristics favor the occurrence of malicious acts. This paper proposes to alert the need of updating the current security protocols, considering the potential association of this technology with radioactive dispersal devices. (author)

  3. Potential seismic structural failure modes associated with the Zion Nuclear Plant. Seismic safety margins research program (Phase I). Project VI. Fragilities

    International Nuclear Information System (INIS)

    1979-10-01

    The Zion 1 and 2 Nuclear Power Plant consists of a number of structures. The most important of these from the viewpoint of safety are the containment buildings, the auxiliary building, the turbine building, and the crib house (or intake structure). The evaluation of the potential seismic failure modes and determination of the ultimate seismic capacity of the structures is a complex undertaking which will require a large number of detailed calculations. As the first step in this evaluation, a number of potential modes of structural failure have been determined and are discussed. The report is principally directed towards seismically induced failure of structures. To some extent, modes involving soil foundation failures are discussed in so far as they affect the buildings. However, failure modes involving soil liquefaction, surface faulting, tsunamis, etc., are considered outside the scope of this evaluation

  4. Quantifying reactor safety margins: Application of CSAU [Code Scalability, Applicability and Uncertainty] methodology to LBLOCA: Part 3, Assessment and ranging of parameters for the uncertainty analysis of LBLOCA codes

    International Nuclear Information System (INIS)

    Wulff, W.; Boyack, B.E.; Duffey, R.B.

    1988-01-01

    Comparisons of results from TRAC-PF1/MOD1 code calculations with measurements from Separate Effects Tests, and published experimental data for modeling parameters have been used to determine the uncertainty ranges of code input and modeling parameters which dominate the uncertainty in predicting the Peak Clad Temperature for a postulated Large Break Loss of Coolant Accident (LBLOCA) in a four-loop Westinghouse Pressurized Water Reactor. The uncertainty ranges are used for a detailed statistical analysis to calculate the probability distribution function for the TRAC code-predicted Peak Clad Temperature, as is described in an attendant paper. Measurements from Separate Effects Tests and Integral Effects Tests have been compared with results from corresponding TRAC-PF1/MOD1 code calculations to determine globally the total uncertainty in predicting the Peak Clad Temperature for LBLOCAs. This determination is in support of the detailed statistical analysis mentioned above. The analyses presented here account for uncertainties in input parameters, in modeling and scaling, in computing and in measurements. The analyses are an important part of the work needed to implement the Code Scalability, Applicability and Uncertainty (CSAU) methodology. CSAU is needed to determine the suitability of a computer code for reactor safety analyses and the uncertainty in computer predictions. The results presented here are used to estimate the safety margin of a particular nuclear reactor power plant for a postulated accident. 25 refs., 10 figs., 11 tabs

  5. Convexity and Marginal Vectors

    NARCIS (Netherlands)

    van Velzen, S.; Hamers, H.J.M.; Norde, H.W.

    2002-01-01

    In this paper we construct sets of marginal vectors of a TU game with the property that if the marginal vectors from these sets are core elements, then the game is convex.This approach leads to new upperbounds on the number of marginal vectors needed to characterize convexity.An other result is that

  6. "We call ourselves marginalized"

    DEFF Research Database (Denmark)

    Jørgensen, Nanna Jordt

    2014-01-01

    of the people we refer to as marginalized. In this paper, I discuss how young secondary school graduates from a pastoralist community in Kenya use and negotiate indigeneity, marginal identity, and experiences of marginalization in social navigations aimed at broadening their current and future opportunities. I...

  7. A study on method to identify actual causes and conditions of safety rule deviations through analyzing events due to unsafe acts of workers

    International Nuclear Information System (INIS)

    Hirotsu, Yuko; Takeda, Daisuke

    2010-01-01

    The purpose of this study is to establish a method to understand actual causes and condition of intentional deviation from safety rules (including norm and written rules that has developed to anticipate, prevent, detect and recover human errors) in an organization by analyzing events due to unsafe acts of workers (human factor events) and to propose effective measures. Firstly, by reviewing literature regarding safety violations, the following two advantages of investigating actual condition of safety rule deviation through human factor event analysis were extracted, such as (a) being able to clarify relationships between deviations, human errors, and events, and (b) being able to identify specific causal factors that influenced the decision to deviate, including acts of people concerned, problems with rules, task demands, environment and management. Next, through the analysis of human factor event data in accordance with existing human error analysis method on the basis of advantages above, the following three requirements for analyzing event data were extracted, such as (a) gathering information such as rules concerning to the work activities related to the human factor events, and whether there are intentional deviations of the rules, (b) gathering information and identify interrelations among causal factors of the intentional deviations, and (c) gathering information on general condition of deviations and the causal factors. (author)

  8. Efficacy and safety of vedolizumab as a treatment option for moderate to severe refractory ulcerative colitis in two patients after liver transplant due to primary sclerosing cholangitis

    Directory of Open Access Journals (Sweden)

    Raúl Vicente Olmedo-Martín

    Full Text Available Vedolizumab is a humanized IgG1 monoclonal antibody that selectively blocks the lymphocyte integrin α4β7 and prevents its interaction with endothelial adhesion molecules and subsequent transmigration to the gastrointestinal tract. The drug was approved in 2014 for the induction and maintenance treatment of ulcerative colitis and moderate to severe Crohn's disease that is refractory or intolerant to conventional treatment with corticoids and immunosuppressants and/or anti-TNFα drugs. However, inflammatory bowel disease has a variable behavior following liver transplant. One third of patients with ulcerative colitis associated with primary sclerosing cholangitis are expected to deteriorate despite receiving immunosuppression to prevent rejection. There is limited experience with anti-TNFα agents in patients with inflammatory bowel disease in the setting of liver transplantation and the studies to date involve a limited number of cases. The efficacy and safety data of vedolizumab in this situation are unreliable and very preliminary. We present two cases with the aim to present the efficacy and safety of vedolizumab after one year of treatment in two patients who underwent a transplant due to primary sclerosing cholangitis. One case had de novo post-transplant ulcerative colitis refractory to two anti-TNFα drugs (golimumab and infliximab. The other patient had a colostomy due to fulminant colitis and developed severe ulcerative proctitis refractory to infliximab after reconstruction with an ileorectal anastomosis.

  9. SAFETY

    CERN Multimedia

    C. Schaefer and N. Dupont

    2013-01-01

      “Safety is the highest priority”: this statement from CERN is endorsed by the CMS management. An interpretation of this statement may bring you to the conclusion that you should stop working in order to avoid risks. If the safety is the priority, work is not! This would be a misunderstanding and misinterpretation. One should understand that “working safely” or “operating safely” is the priority at CERN. CERN personnel are exposed to different hazards on many levels on a daily basis. However, risk analyses and assessments are done in order to limit the number and the gravity of accidents. For example, this process takes place each time you cross the road. The hazard is the moving vehicle, the stake is you and the risk might be the risk of collision between both. The same principle has to be applied during our daily work. In particular, keeping in mind the general principles of prevention defined in the late 1980s. These principles wer...

  10. Marginalization of the Youth

    DEFF Research Database (Denmark)

    Jensen, Niels Rosendal

    2009-01-01

    The article is based on a key note speach in Bielefeld on the subject "welfare state and marginalized youth", focusing upon the high ambition of expanding schooling in Denmark from 9 to 12 years. The unintended effect may be a new kind of marginalization.......The article is based on a key note speach in Bielefeld on the subject "welfare state and marginalized youth", focusing upon the high ambition of expanding schooling in Denmark from 9 to 12 years. The unintended effect may be a new kind of marginalization....

  11. Safety

    International Nuclear Information System (INIS)

    Jones, P.M.S.

    1987-01-01

    Aspects of fission reactors are considered - control, heat removal and containment. Brief descriptions of the reactor accidents at the SL-1 reactor (1961), Windscale (1957), Browns Ferry (1975), Three Mile Island (1979) and Chernobyl (1986) are given. The idea of inherently safe reactor designs is discussed. Safety assessment is considered under the headings of preliminary hazard analysis, failure mode analysis, event trees, fault trees, common mode failure and probabalistic risk assessments. These latter can result in a series of risk distributions linked to specific groups of fault sequences and specific consequences. A frequency-consequence diagram is shown. Fatal accident incidence rates in different countries including the United Kingdom for various industries are quoted. The incidence of fatal cancers from occupational exposure to chemicals is tabulated. Human factors and the acceptability of risk are considered. (U.K.)

  12. Characterization of Stream Channel Evolution Due to Extensional Tectonics Along the Western Margin of North Boulder Basin (Bull Mountain), SW Montana with the Use of Geologic Mapping and Thermochronologic (U-Th/He) Dating.

    Science.gov (United States)

    Cataldo, K.; Douglas, B. J.; Yanites, B.

    2017-12-01

    Landscape response to active tectonics, such as fault motion or regional uplift, can be recorded in river profiles as changes in slope (i.e. knickpoints) or topography. North Boulder basin region (SW Montana), experienced two separate phases of extension, from 45 - 35 Ma and again beginning 14 Ma to the present, producing basin-and-range style fault-blocks. Focusing on the Bull Mountain region, located on the western margin of the North Boulder basin, data is collected to test the hypothesis that Bull Mountain is located on the hanging wall of a half-graben. Our objective is to elucidate the active tectonics of the study area within a regional context by utilizing river profile analysis and thermochronometric data. High-resolution (distribution of water, which is an important commodity in SW Montana for ranchers and farmers. Thus, the ability to discern the probability of recurring tectonic events and the effects on the regional watersheds, could help facilitate solutions before these events take place.

  13. Study of the Efficacy, Safety and Tolerability of Low-Molecular-Weight Heparin vs. Unfractionated Heparin as Bridging Therapy in Patients with Embolic Stroke due to Atrial Fibrillation.

    Science.gov (United States)

    Feiz, Farnia; Sedghi, Reyhane; Salehi, Alireza; Hatam, Nahid; Bahmei, Jamshid; Borhani-Haghighi, Afshin

    2016-06-01

    Anticoagulation with adjusted dose warfarin is a well-accepted treatment for the prevention of recurrent stroke in patients with atrial fibrillation. Meanwhile, using bridging therapy with heparin or heparinoids before warfarin for initiation of anticoagulation is a matter of debate. We compared safety, efficacy, and tolerability of low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) as a bridging method in patients with recent ischemic stroke due to atrial fibrillation. This study was a randomized single-blind controlled trial in patients with acute ischemic stroke due to atrial fibrillation who were eligible for receiving warfarin and were randomly treated with 60 milligrams (mg) of LMWH (enoxaparin) subcutaneously every 12 h, or 1000 units/h of continuous intravenous heparin. The primary efficacy endpoints were recurrence of new ischemic stroke, myocardial infarction and/or death. The primary safety endpoint was central nervous system and/or systemic bleeding. Seventy-four subjects were recruited. Baseline demographic and clinical characteristics of two groups were matched. Composite endpoint outcome of new ischemic stroke, myocardial infarction, and/or death in follow-up period was seen in 10 subjects (27.03%) in UFH group and in four subjects (10.81%) in LMWH group (p value: 0.136). All hemorrhages and symptomatic central nervous system (CNS) hemorrhages in follow-up period were in 7 (18.9%) and 4 (10.8%) patients in UFH group, in 5 (13.5%), and 3 (8.1%) patients in LMWH group (p values: 0.754 and 0.751), respectively. Drop out and major adverse-effects such as heparin-induced thrombocytopenia and drug hypersensitivity were not seen in any patient. Enoxaparin can be a safe and efficient alternative for UFH as bridging therapy.

  14. On marginal regeneration

    NARCIS (Netherlands)

    Stein, H.N.

    1991-01-01

    On applying the marginal regeneration concept to the drainage of free liquid films, problems are encountered: the films do not show a "neck" of minimum thickness at the film/border transition; and the causes of the direction dependence of the marginal regeneration are unclear. Both problems can be

  15. Indian Ocean margins

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A

    in the latter two areas. Some of these fluxes are expected to be substantial in the case of Indonesian continental margins and probably also across the eastern coasts of Africa not covered in this chapter. However, a dearth of information makes these margins...

  16. Matthew and marginality

    Directory of Open Access Journals (Sweden)

    Denis C. Duling

    1995-12-01

    Full Text Available This article explores marginality theory as it was first proposed in  the social sciences, that is related to persons caught between two competing cultures (Park; Stonequist, and, then, as it was developed in sociology as related to the poor (Germani and in anthropology as it was related to involuntary marginality and voluntary marginality (Victor Turner. It then examines a (normative scheme' in antiquity that creates involuntary marginality at the macrosocial level, namely, Lenski's social stratification model in an agrarian society, and indicates how Matthean language might fit with a sample inventory  of socioreligious roles. Next, it examines some (normative schemes' in  antiquity for voluntary margi-nality at the microsocial level, namely, groups, and examines how the Matthean gospel would fit based on indications of factions and leaders. The article ,shows that the author of the Gospel of Matthew has an ideology of (voluntary marginality', but his gospel includes some hope for (involuntary  marginals' in  the  real world, though it is somewhat tempered. It also suggests that the writer of the Gospel is a (marginal man', especially in the sense defined by the early theorists (Park; Stone-quist.

  17. Fixing soft margins

    NARCIS (Netherlands)

    P. Kofman (Paul); A. Vaal, de (Albert); C.G. de Vries (Casper)

    1993-01-01

    textabstractNon-parametric tolerance limits are employed to calculate soft margins such as advocated in Williamson's target zone proposal. In particular, the tradeoff between softness and zone width is quantified. This may be helpful in choosing appropriate margins. Furthermore, it offers

  18. NRC Seismic Design Margins Program Plan

    International Nuclear Information System (INIS)

    Cummings, G.E.; Johnson, J.J.; Budnitz, R.J.

    1985-08-01

    Recent studies estimate that seismically induced core melt comes mainly from earthquakes in the peak ground acceleration range from 2 to 4 times the safe shutdown earthquake (SSE) acceleration used in plant design. However, from the licensing perspective of the US Nuclear Regulatory Commission, there is a continuing need for consideration of the inherent quantitative seismic margins because of, among other things, the changing perceptions of the seismic hazard. This paper discusses a Seismic Design Margins Program Plan, developed under the auspices of the US NRC, that provides the technical basis for assessing the significance of design margins in terms of overall plant safety. The Plan will also identify potential weaknesses that might have to be addressed, and will recommend technical methods for assessing margins at existing plants. For the purposes of this program, a general definition of seismic design margin is expressed in terms of how much larger that the design basis earthquake an earthquake must be to compromise plant safety. In this context, margin needs to be determined at the plant, system/function, structure, and component levels. 14 refs., 1 fig

  19. Evaluation of the Safety Issue Concerning the Potential for Loss of Decay Heat Removal Function due to Crude Oil Spill in the Ultimate Heat Sink of Nuclear Reactors

    International Nuclear Information System (INIS)

    Jo, Jong Chull; Roh, Kyung Wan; Yune, Young Gill; Kang, Dong Gu; Kim, Hho Jhung

    2008-01-01

    A barge crashed into a moored oil tanker at about 7:15 a.m., Dec. 12, 2007, dumping around 10,500 tons of crude oil into the sea in Korea. The incident took place about 15 kilometers northwest of Manripo beach in South Chungcheong where is Korea's west coast in the Yellow Sea. In a few days, the oil slicks spread to the northern and southern tips of the Taean Peninsula by strong winds and tides. As time went the spilled oil floating on the surface of sea water was volatilized to become tar-balls and lumps and drifted far away in the southern direction. 13 days after the incident, some of oil slicks and tar lumps were observed to flow in the service water intake at the Younggwang nuclear power plants (NPPs) operating 6 reactors, which are over 150 km away from the incident spot in the southeastern direction. According to the report by the Younggwang NPPs, a total weight 83 kg of tar lumps was removed for about 3 days. Oil spills in the sea can happen in any country or anytime due to human errors or mistakes, wars, terrors, intentional dumping of waste oils, and natural disasters like typhoon and tsunami. In fact, there have been 7 major oil spills over 10,000 tons that have occurred around the world since 1983. As such serious oil spill incidents may happen near the operating power plants using the sea water as ultimate heat sink. To ensure the safe operation of nuclear reactors it is required to evaluate the potential for loss of decay heat removal function of nuclear reactors due to the spilled oils flowing in the service water intake, from which the service water is pumped. Thus, Korea Institute of Nuclear Safety identified this problem as one of the important safety. When an incident of crude oil spill from an oil carrier occurs in the sea near the nuclear power plants, the spilled oil can be transported to the intake pit, where all service water pumps locate, by sea current and wind drift (induced) current. The essential service water pumps take the service

  20. Evaluation of the Safety Issue Concerning the Potential for Loss of Decay Heat Removal Function due to Crude Oil Spill in the Ultimate Heat Sink of Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jong Chull; Roh, Kyung Wan; Yune, Young Gill; Kang, Dong Gu; Kim, Hho Jhung [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2008-05-15

    A barge crashed into a moored oil tanker at about 7:15 a.m., Dec. 12, 2007, dumping around 10,500 tons of crude oil into the sea in Korea. The incident took place about 15 kilometers northwest of Manripo beach in South Chungcheong where is Korea's west coast in the Yellow Sea. In a few days, the oil slicks spread to the northern and southern tips of the Taean Peninsula by strong winds and tides. As time went the spilled oil floating on the surface of sea water was volatilized to become tar-balls and lumps and drifted far away in the southern direction. 13 days after the incident, some of oil slicks and tar lumps were observed to flow in the service water intake at the Younggwang nuclear power plants (NPPs) operating 6 reactors, which are over 150 km away from the incident spot in the southeastern direction. According to the report by the Younggwang NPPs, a total weight 83 kg of tar lumps was removed for about 3 days. Oil spills in the sea can happen in any country or anytime due to human errors or mistakes, wars, terrors, intentional dumping of waste oils, and natural disasters like typhoon and tsunami. In fact, there have been 7 major oil spills over 10,000 tons that have occurred around the world since 1983. As such serious oil spill incidents may happen near the operating power plants using the sea water as ultimate heat sink. To ensure the safe operation of nuclear reactors it is required to evaluate the potential for loss of decay heat removal function of nuclear reactors due to the spilled oils flowing in the service water intake, from which the service water is pumped. Thus, Korea Institute of Nuclear Safety identified this problem as one of the important safety. When an incident of crude oil spill from an oil carrier occurs in the sea near the nuclear power plants, the spilled oil can be transported to the intake pit, where all service water pumps locate, by sea current and wind drift (induced) current. The essential service water pumps take the

  1. SOCIAL MARGINALIZATION AND HEALTH

    Directory of Open Access Journals (Sweden)

    Marjana Bogdanović

    2007-04-01

    Full Text Available The 20th century was characterized by special improvement in health. The aim of WHO’s policy EQUITY IN HEALTH is to enable equal accessibility and equal high quality of health care for all citizens. More or less some social groups have stayed out of many social systems even out of health care system in the condition of social marginalization. Phenomenon of social marginalization is characterized by dynamics. Marginalized persons have lack of control over their life and available resources. Social marginalization stands for a stroke on health and makes the health status worse. Low socio-economic level dramatically influences people’s health status, therefore, poverty and illness work together. Characteristic marginalized groups are: Roma people, people with AIDS, prisoners, persons with development disorders, persons with mental health disorders, refugees, homosexual people, delinquents, prostitutes, drug consumers, homeless…There is a mutual responsibility of community and marginalized individuals in trying to resolve the problem. Health and other problems could be solved only by multisector approach to well-designed programs.

  2. Safety and long-term efficacy of transition from sildenafil to tadalafil due to side effects in patients with pulmonary arterial hypertension.

    Science.gov (United States)

    Lichtblau, Mona; Harzheim, Dominik; Ehlken, Nicola; Marra, Alberto; Pinado, Fabiola Pena; Grünig, Ekkehard; Egenlauf, Benjamin

    2015-02-01

    Two phosphodiesterase-type 5 (PDE-5) inhibitors, sildenafil and tadalafil, are approved for treatment of pulmonary arterial hypertension (PAH). It has not yet been observed if transition from sildenafil to tadalafil is beneficial in patients suffering from adverse reactions. Aim of this study was to analyze safety and long-term effects in PAH patients whose treatment was transitioned from sildenafil to tadalafil due to intolerable side-effects. A retrospective analysis of PAH-patients who were stable on sildenafil for >3 months and transitioned to tadalafil due to adverse events was performed. Data collected included demographics, PAH-etiology, WHO-functional class, 6 min walking distance (6MWD), echocardiography, lung function tests, and NTproBNP pre-transition and 3, 6, and 12 months post-transition. Included were 13 PAH patients (8 females mean age 64 ± 10 years) who had been on sildenafil for a mean of 12 ± 8.4 months. In six patients (46.1 %) a switch to tadalafil was feasible and resulted in tolerable side effects and a stable clinical course with improvement of symptoms, 6MWD, stable echocardiographic findings, and NTproBNP-levels during a follow-up of 11 ± 3 months. In 5 out of 13 patients (38.5 %) adverse events occurred under tadalafil as well and therapy with PDE-5 inhibitors was discontinued. In two patients (15.4 %) sildenafil-treatment could be successfully restarted after an intermittent switch to tadalafil. The observations of this study indicate that a transition of sildenafil to tadalafil in case of intolerable side effects is a reasonable therapy option in about 50 % of the patients. These results should be verified by a larger prospective study.

  3. Evaluation of thermal margin for HANARO core

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cheol; Chae, Hee Taek; Kim Heon Il; Lim, I. C.; Lee, C. S.; Kim, H

    1999-08-01

    During the commissioning and the start-up of the HANARO, various design parameters were confirmed and measured. For safer operation of HANARO and resolution of the CHF penalty issue which is one of unresolved licensing problems, thermal margins for normal and transient conditions were re-evaluated reflecting the commissioning and the start-up test results and the design modifications during operation. The re-evaluation shows that the HANARO meets the design criteria for ONB margin and fuel centerline temperature under normal condition. For upset condition, it also satisfies the safety limits for CHFR and fuel centerline temperature. (Author). 11 refs., 13 tabs., 4 figs.

  4. Quantification of microbial quality and safety in minimally processed foods

    NARCIS (Netherlands)

    Zwietering, M.H.

    2002-01-01

    To find a good equilibrium between quality and margin of safety of minimally processed foods, often various hurdles are used. Quantification of the kinetics should be used to approach an optimum processing and to select the main aspects. Due to many factors of which the exact quantitative effect is

  5. From Borders to Margins

    DEFF Research Database (Denmark)

    Parker, Noel

    2009-01-01

    of entities that are ever open to identity shifts.  The concept of the margin possesses a much wider reach than borders, and focuses continual attention on the meetings and interactions between a range of indeterminate entities whose interactions may determine both themselves and the types of entity...... upon Deleuze's philosophy to set out an ontology in which the continual reformulation of entities in play in ‘post-international' society can be grasped.  This entails a strategic shift from speaking about the ‘borders' between sovereign states to referring instead to the ‘margins' between a plethora...

  6. Splenic marginal zone lymphoma.

    Science.gov (United States)

    Piris, Miguel A; Onaindía, Arantza; Mollejo, Manuela

    Splenic marginal zone lymphoma (SMZL) is an indolent small B-cell lymphoma involving the spleen and bone marrow characterized by a micronodular tumoral infiltration that replaces the preexisting lymphoid follicles and shows marginal zone differentiation as a distinctive finding. SMZL cases are characterized by prominent splenomegaly and bone marrow and peripheral blood infiltration. Cells in peripheral blood show a villous cytology. Bone marrow and peripheral blood characteristic features usually allow a diagnosis of SMZL to be performed. Mutational spectrum of SMZL identifies specific findings, such as 7q loss and NOTCH2 and KLF2 mutations, both genes related with marginal zone differentiation. There is a striking clinical variability in SMZL cases, dependent of the tumoral load and performance status. Specific molecular markers such as 7q loss, p53 loss/mutation, NOTCH2 and KLF2 mutations have been found to be associated with the clinical variability. Distinction from Monoclonal B-cell lymphocytosis with marginal zone phenotype is still an open issue that requires identification of precise and specific thresholds with clinical meaning. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Komorbiditet ved marginal parodontitis

    DEFF Research Database (Denmark)

    Holmstrup, Palle; Damgaard, Christian; Olsen, Ingar

    2017-01-01

    Nærværende artikel præsenterer en oversigt over den foreliggende væsentligste viden om sammenhængen mellem marginal parodontitis og en række medicinske sygdomme, herunder hjerte-kar-sygdomme, diabetes mellitus, reumatoid arthritis, osteoporose, Parkinsons sygdom, Alzheimers sygdom, psoriasis og...

  8. Marginally Deformed Starobinsky Gravity

    DEFF Research Database (Denmark)

    Codello, A.; Joergensen, J.; Sannino, Francesco

    2015-01-01

    We show that quantum-induced marginal deformations of the Starobinsky gravitational action of the form $R^{2(1 -\\alpha)}$, with $R$ the Ricci scalar and $\\alpha$ a positive parameter, smaller than one half, can account for the recent experimental observations by BICEP2 of primordial tensor modes....

  9. Deep continental margin reflectors

    Science.gov (United States)

    Ewing, J.; Heirtzler, J.; Purdy, M.; Klitgord, Kim D.

    1985-01-01

    In contrast to the rarity of such observations a decade ago, seismic reflecting and refracting horizons are now being observed to Moho depths under continental shelves in a number of places. These observations provide knowledge of the entire crustal thickness from the shoreline to the oceanic crust on passive margins and supplement Consortium for Continental Reflection Profiling (COCORP)-type measurements on land.

  10. Marginalization and School Nursing

    Science.gov (United States)

    Smith, Julia Ann

    2004-01-01

    The concept of marginalization was first analyzed by nursing researchers Hall, Stevens, and Meleis. Although nursing literature frequently refers to this concept when addressing "at risk" groups such as the homeless, gays and lesbians, and those infected with HIV/AIDS, the concept can also be applied to nursing. Analysis of current school nursing…

  11. Design and safety aspects of nuclear district heating reactors

    International Nuclear Information System (INIS)

    Brogli, R.; Mathews, D.; Pelloni, S.

    1989-01-01

    Extensive studies on the rationale, the potential and the technology of nuclear district heating have been performed in Switzerland. Beside economics the safety aspects were of primary importance. Due to the high costs to transport heat the heating reactor tend to be small and therefore, minimally staffed and located close to population centers. Stringed safety rules are therefore applying. Gas cooled reactors are well suited as district heating reactors since they have due to their characteristics several inherent features, significant safety margins and a remarkable radioactivity retention potential. Some ways to mitigate the effects of water ingress and graphite corrosion are under investigation. (author). 5 refs, 3 figs

  12. A Phase 3, Randomized, Double-Blind, Multicenter Study to Evaluate the Safety and Efficacy of Intravenous Iclaprim Vs Vancomycin for the Treatment of Acute Bacterial Skin and Skin Structure Infections Suspected or Confirmed to be Due to Gram-Positive Pathogens: REVIVE-1.

    Science.gov (United States)

    Huang, David B; O'Riordan, William; Overcash, J Scott; Heller, Barry; Amin, Faisal; File, Thomas M; Wilcox, Mark H; Torres, Antoni; Dryden, Matthew; Holland, Thomas L; McLeroth, Patrick; Shukla, Rajesh; Corey, G Ralph

    2018-04-03

    Our objective in this study was to demonstrate the safety and efficacy of iclaprim compared with vancomycin for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSIs). REVIVE-1 was a phase 3, 600-patient, double-blinded, randomized (1:1), active-controlled trial among patients with ABSSSI that compared the safety and efficacy of iclaprim 80 mg fixed dose with vancomycin 15 mg/kg, both administered intravenously every 12 hours for 5-14 days. The primary endpoint of this study was a ≥20% reduction in lesion size (early clinical response [ECR]) compared with baseline among patients randomized to iclaprim or vancomycin at the early time point (ETP), 48 to 72 hours after the start of administration of study drug in the intent-to-treat population. ECR among patients who received iclaprim and vancomycin at the ETP was 80.9% (241 of 298) of patients receiving iclaprim compared with 81.0% (243 of 300) of those receiving vancomycin (treatment difference, -0.13%; 95% confidence interval, -6.42%-6.17%). Iclaprim was well tolerated in the study, with most adverse events categorized as mild. Iclaprim achieved noninferiority (10% margin) at ETP compared with vancomycin and was well tolerated in this phase 3 clinical trial for the treatment of ABSSSI. Based on these results, iclaprim appears to be an efficacious and safe treatment for ABSSSI suspected or confirmed to be due to gram-positive pathogens. NCT02600611.

  13. Risk insights from seismic margin reviews

    International Nuclear Information System (INIS)

    Budnitz, R.J.

    1990-01-01

    This paper discusses the information that has been derived from the three seismic-margin reviews conducted so far, and the information that is potentially available from using the seismic-margin method more generally. There are two different methodologies for conducting seismic margin reviews of nuclear power plants, one developed under NRC sponsorship and one developed under sponsorship of the Electric Power Research Institute. Both methodologies will be covered in this paper. The paper begins with a summary of the steps necessary to complete a margin review, and will then outline the key technical difficulties that need to be addressed. After this introduction, the paper covers the safety and operational insights derived from the three seismic-margin reviews already completed: the NRC-sponsored review at Maine Yankee; the EPRI-sponsored review at Catawba; and the joint EPRI/NRC/utility effort at Hatch. The emphasis is on engineering insights, with attention to the aspects of the reviews that are easiest to perform and that provide the most readily available insights

  14. Middlemen Margins and Globalization

    OpenAIRE

    Pranab Bardhan; Dilip Mookherjee; Masatoshi Tsumagari

    2013-01-01

    We develop a theory of trading middlemen or entrepreneurs who perform financing, quality supervision and marketing roles for goods produced by suppliers or workers. Brand-name reputations are necessary to overcome product quality moral hazard problems; middlemen margins represent reputational incentive rents. We develop a two sector North-South model of competitive equilibrium, with endogenous sorting of agents with heterogenous entrepreneurial abilities into sectors and occupations. The Sout...

  15. Marginalized Youth. An Introduction.

    OpenAIRE

    Kessl, Fabian; Otto, Hans-Uwe

    2009-01-01

    The life conduct of marginalized groups has become subject to increasing levels of risk in advanced capitalist societies. In particular, children and young people are confronted with the harsh consequences of a “new poverty” in the contemporary era. The demographic complexion of today’s poverty is youthful, as a number of government reports have once again documented in recent years in Australia, Germany, France, Great Britain, the US or Scandinavian countries. Key youth studies have shown a ...

  16. Safety and efficacy of diaphragm pacing in patients with respiratory insufficiency due to amyotrophic lateral sclerosis (DiPALS): a multicentre, open-label, randomised controlled trial.

    Science.gov (United States)

    2015-09-01

    Non-invasive ventilation is part of the standard of care for treatment of respiratory failure in patients with amyotrophic lateral sclerosis (ALS). The NeuRx RA/4 Diaphragm Pacing System has received Humanitarian Device Exemption approval from the US Food and Drug Administration for treatment of respiratory failure in patients with ALS. We aimed to establish the safety and efficacy of diaphragm pacing with this system in patients with respiratory muscle weakness due to ALS. We undertook a multicentre, open-label, randomised controlled trial at seven specialist ALS and respiratory centres in the UK. Eligible participants were aged 18 years or older with laboratory supported probable, clinically probable, or clinically definite ALS; stable riluzole treatment for at least 30 days; and respiratory insufficiency. We randomly assigned participants (1:1), via a centralised web-based randomisation system with minimisation that balanced patients for age, sex, forced vital capacity, and bulbar function, to receive either non-invasive ventilation plus pacing with the NeuRx RA/4 Diaphragm Pacing System or non-invasive ventilation alone. Patients, carers, and outcome assessors were not masked to treatment allocation. The primary outcome was overall survival, defined as the time from randomisation to death from any cause. Analysis was by intention to treat. This trial is registered, ISRCTN number 53817913. Between Dec 5, 2011, and Dec 18, 2013, we randomly assigned 74 participants to receive either non-invasive ventilation alone (n=37) or non-invasive ventilation plus diaphragm pacing (n=37). On Dec 18, 2013, the Data Monitoring and Ethics Committee (DMEC) recommended suspension of recruitment on the basis of overall survival figures. Randomly assigned participants continued as per the study protocol until June 23, 2014, when the DMEC advised discontinuation of pacing in all patients. Follow-up assessments continued until the planned end of the study in December, 2014. Survival

  17. Marginal Models for Categorial Data

    NARCIS (Netherlands)

    Bergsma, W.P.; Rudas, T.

    2002-01-01

    Statistical models defined by imposing restrictions on marginal distributions of contingency tables have received considerable attention recently. This paper introduces a general definition of marginal log-linear parameters and describes conditions for a marginal log-linear parameter to be a smooth

  18. Masculinity at the margins

    DEFF Research Database (Denmark)

    Jensen, Sune Qvotrup

    2010-01-01

    and other types of material. Taking the concepts of othering, intersectionality and marginality as point of departure the article analyses how these young men experience othering and how they react to it. One type of reaction, described as stylization, relies on accentuating the latently positive symbolic...... of critique although in a masculinist way. These reactions to othering represent a challenge to researchers interested in intersectionality and gender, because gender is reproduced as a hierarchical form of social differentiation at the same time as racism is both reproduced and resisted....

  19. Refining prices and margins in 1998

    International Nuclear Information System (INIS)

    Favennec, J.P.; Baudoin, C.

    1999-01-01

    Despite a business environment that was globally mediocre due primarily to the Asian crisis and to a mild winter in the northern hemisphere, the signs of improvement noted in the refining activity in 1996 were borne out in 1997. But the situation is not yet satisfactory in this sector: the low return on invested capital and the financing of environmental protection expenditure are giving cause for concern. In 1998, the drop in crude oil prices and the concomitant fall in petroleum product prices was ultimately rather favorable to margins. Two elements tended to put a damper on this relative optimism. First of all, margins continue to be extremely volatile and, secondly, the worsening of the economic and financial crisis observed during the summer made for a sharp decline in margins in all geographic regions, especially Asia

  20. A Politics of Marginability

    DEFF Research Database (Denmark)

    Pallesen, Cecil Marie

    2015-01-01

    always been contested and to some extent vulnerable. However, the Indian communities are strong socially and economically, and the vast majority of its people have great international networks and several potential plans or strategies for the future, should the political climate in Tanzania become......In the end of the 19th century, Indians began settling in East Africa. Most of them left Gujarat because of drought and famine, and they were in search for business opportunities and a more comfortable life. Within the following decades, many of them went from being small-scale entrepreneurs to big...... hostile towards them. I argue that this migrant group is unique being marginalized and strong at the same time, and I explain this uniqueness by several features in the Indian migrants’ cultural and religious background, in colonial and post-colonial Tanzania, and in the Indians’ role as middlemen between...

  1. Preliminary safety evaluation for CSR1000 with passive safety system

    International Nuclear Information System (INIS)

    Wu, Pan; Gou, Junli; Shan, Jianqiang; Zhang, Bo; Li, Xiang

    2014-01-01

    Highlights: • The basic information of a Chinese SCWR concept CSR1000 is introduced. • An innovative passive safety system is proposed for CSR1000. • 6 Transients and 3 accidents are analysed with system code SCTRAN. • The passive safety systems greatly mitigate the consequences of these incidents. • The inherent safety of CSR1000 is enhanced. - Abstract: This paper describes the preliminary safety analysis of the Chinese Supercritical water cooled Reactor (CSR1000), which is proposed by Nuclear Power Institute of China (NPIC). The two-pass core design applied to CSR1000 decreases the fuel cladding temperature and flattens the power distribution of the core at normal operation condition. Each fuel assembly is made up of four sub-assemblies with downward-flow water rods, which is favorable to the core cooling during abnormal conditions due to the large water inventory of the water rods. Additionally, a passive safety system is proposed for CSR1000 to increase the safety reliability at abnormal conditions. In this paper, accidents of “pump seizure”, “loss of coolant flow accidents (LOFA)”, “core depressurization”, as well as some typical transients are analysed with code SCTRAN, which is a one-dimensional safety analysis code for SCWRs. The results indicate that the maximum cladding surface temperatures (MCST), which is the most important safety criterion, of the both passes in the mentioned incidents are all below the safety criterion by a large margin. The sensitivity analyses of the delay time of RCPs trip in “loss of offsite power” and the delay time of RMT actuation in “loss of coolant flowrate” were also included in this paper. The analyses have shown that the core design of CSR1000 is feasible and the proposed passive safety system is capable of mitigating the consequences of the selected abnormalities

  2. Criticality Safety Evaluation of Hanford Tank Farms Facility

    Energy Technology Data Exchange (ETDEWEB)

    WEISS, E.V.

    2000-12-15

    Data and calculations from previous criticality safety evaluations and analyses were used to evaluate criticality safety for the entire Tank Farms facility to support the continued waste storage mission. This criticality safety evaluation concludes that a criticality accident at the Tank Farms facility is an incredible event due to the existing form (chemistry) and distribution (neutron absorbers) of tank waste. Limits and controls for receipt of waste from other facilities and maintenance of tank waste condition are set forth to maintain the margin subcriticality in tank waste.

  3. Criticality Safety Evaluation of Hanford Tank Farms Facility

    International Nuclear Information System (INIS)

    WEISS, E.V.

    2000-01-01

    Data and calculations from previous criticality safety evaluations and analyses were used to evaluate criticality safety for the entire Tank Farms facility to support the continued waste storage mission. This criticality safety evaluation concludes that a criticality accident at the Tank Farms facility is an incredible event due to the existing form (chemistry) and distribution (neutron absorbers) of tank waste. Limits and controls for receipt of waste from other facilities and maintenance of tank waste condition are set forth to maintain the margin subcriticality in tank waste

  4. Project margins of advanced reactor design WWER-500

    International Nuclear Information System (INIS)

    Rogov, M.F.; Birukov, G.I.; Ershov, V.G.; Volkov, B.E.

    1994-01-01

    Project criteria for design of advanced WWER-500 reactor within design conditions are compared to the requirements of the Russian regulatory guides. Normal operation limits, safe operation limits for main anticipated operational occurrences and design limits accepted for design basis accidents are considered as in preliminary safety report. It is shown that the basic design criteria in the design of WWER-500 for the anticipated operational occurrences and for design basis accidents are more severe than required in the following regulatory guides General Safety Regulations for Nuclear Power Plants and Nuclear Safety Rules for Reactors of Nuclear Power Plants. This provides certain margins from safety point of view

  5. Reactor system safety assurance

    International Nuclear Information System (INIS)

    Mattson, R.J.

    1984-01-01

    The philosophy of reactor safety is that design should follow established and conservative engineering practices, there should be safety margins in all modes of plant operation, special systems should be provided for accidents, and safety systems should have redundant components. This philosophy provides ''defense in depth.'' Additionally, the safety of nuclear power plants relies on ''safety systems'' to assure acceptable response to design basis events. Operating experience has shown the need to study plant response to more frequent upset conditions and to account for the influence of operators and non-safety systems on overall performance. Defense in depth is being supplemented by risk and reliability assessment

  6. A comparative randomized prospective study to evaluate efficacy and safety of combination of tamsulosin and tadalafil vs. tamsulosin or tadalafil alone in patients with lower urinary tract symptoms due to benign prostatic hyperplasia.

    Science.gov (United States)

    Singh, Dig Vijay; Mete, Uttam Kumar; Mandal, Arup Kumar; Singh, Shrawan Kumar

    2014-01-01

    Lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) and erectile dysfunction are common disorders of advancing age. To evaluate the efficacy and safety of tamsulosin and tadalafil in patients with LUTS due to BPH. In this prospective randomized study, 133 men complaining of LUTS due to BPH were included. Forty-five patients received tamsulosin 0.4 mg/day alone (Group A), 44 patients received tadalafil 10 mg/day (Group B), and combination therapy (tamsulosin and tadalafil both) was instituted in 44 patients (Group C). After a 2-week medication free run-in period, they were evaluated for International Prostatic Symptom Score (IPSS), International Index of Erectile Function score (IIEF5), quality of life (IPSS QoL), maximum urinary flow rate (Qmax), post-void residual urine (PVR) volume, and safety parameters before and at 3 months of treatment. There were primary (IPSS, IPSS QoL index, Qmax, and PVR) and secondary (erectile function [EF] domain scores from IIEF5) efficacy end points. Safety assessment included laboratory tests and patient's reporting of adverse event. A significant improvement in IPSS score was observed in all the 3 groups A, B, and C (-50.90%, P tamsulosin and tadalafil alone or in combination cause a significant improvement in patients with LUTS. Their EF also improves with these medications. The improvement is better with combination therapy compared with single agent alone. © 2013 International Society for Sexual Medicine.

  7. Operation in low edge safety factor regime and passive disruption avoidance due to stellarator rotational transform in the Compact Toroidal Hybrid

    Science.gov (United States)

    Pandya, M. D.; Ennis, D. A.; Hartwell, G. J.; Maurer, D. A.

    2015-11-01

    Low edge safety factor operation at a value less than two (q (a) = 1 /ttot (a) routine on the Compact Toroidal Hybrid device. Presently, the operational space of this current carrying stellarator extends down to q (a) = 1 . 2 without significant n = 1 kink mode activity after the initial plasma current rise of the discharge. The disruption dynamics of these low q (a) plasmas depend upon the fraction of rotational transform produced by external stellarator coils to that generated by the plasma current. We observe that when about 10% of the total rotational transform is supplied by the stellarator coils, low q (a) disruptions are passively suppressed and avoided even though q (a) disrupt, the instability precursors measured and implicated as the cause are internal tearing modes with poloidal, m, and toroidal, n, mode numbers of m / n = 3 / 2 and 4 / 3 observed by external magnetic sensors, and m / n = 1 / 1 activity observed by core soft x-ray emissivity measurements. Even though q (a) passes through and becomes much less than two, external n = 1 kink mode activity does not appear to play a significant role in the observed disruption phenomenology. This work is supported by US Department of Energy Grant No. DE-FG02-00ER54610.

  8. The stability margin on EAST tokamak

    International Nuclear Information System (INIS)

    Jin-Ping, Qian; Bao-Nian, Wan; Biao, Shen; Bing-Jia, Xiao; Walker, M.L.; Humphreys, D.A.

    2009-01-01

    The experimental advanced superconducting tokamak (EAST) is the first full superconducting tokamak with a D-shaped cross-sectional plasma presently in operation. Its poloidal coils are relatively far from the plasma due to the necessary thermal isolation from the superconducting magnets, which leads to relatively weaker coupling between plasma and poloidal field. This may cause more difficulties in controlling the vertical instability by using the poloidal coils. The measured growth rates of vertical stability are compared with theoretical calculations, based on a rigid plasma model. Poloidal beta and internal inductance are varied to investigate their effects on the stability margin by changing the values of parameters α n and γ n (Howl et al 1992 Phys. Fluids B 4 1724), with plasma shape fixed to be a configuration with k = 1.9 and δ = 0.5. A number of ways of studying the stability margin are investigated. Among them, changing the values of parameters κ and l i is shown to be the most effective way to increase the stability margin. Finally, a guideline of stability margin M s (κ, l i , A) to a new discharge scenario showing whether plasmas can be stabilized is also presented in this paper

  9. Workers' marginal costs of commuting

    DEFF Research Database (Denmark)

    van Ommeren, Jos; Fosgerau, Mogens

    2009-01-01

    This paper applies a dynamic search model to estimate workers' marginal costs of commuting, including monetary and time costs. Using data on workers' job search activity as well as moving behaviour, for the Netherlands, we provide evidence that, on average, workers' marginal costs of one hour...

  10. Efficacy and safety of fosfomycin plus imipenem as rescue therapy for complicated bacteremia and endocarditis due to methicillin-resistant Staphylococcus aureus: a multicenter clinical trial.

    Science.gov (United States)

    del Río, Ana; Gasch, Oriol; Moreno, Asunción; Peña, Carmen; Cuquet, Jordi; Soy, Dolors; Mestres, Carlos A; Suárez, Cristina; Pare, Juan C; Tubau, Fe; Garcia de la Mària, Cristina; Marco, Francesc; Carratalà, Jordi; Gatell, José M; Gudiol, Francisco; Miró, José M

    2014-10-15

    There is an urgent need for alternative rescue therapies in invasive infections caused by methicillin-resistant Staphylococcus aureus (MRSA). We assessed the clinical efficacy and safety of the combination of fosfomycin and imipenem as rescue therapy for MRSA infective endocarditis and complicated bacteremia. The trial was conducted between 2001 and 2010 in 3 Spanish hospitals. Adult patients with complicated MRSA bacteremia or endocarditis requiring rescue therapy were eligible for the study. Treatment with fosfomycin (2 g/6 hours IV) plus imipenem (1 g/6 hours IV) was started and monitored. The primary efficacy endpoints were percentage of sterile blood cultures at 72 hours and clinical success rate assessed at the test-of-cure visit (45 days after the end of therapy). The combination was administered in 12 patients with endocarditis, 2 with vascular graft infection, and 2 with complicated bacteremia. Therapy had previously failed with vancomycin in 9 patients, daptomycin in 2, and sequential antibiotics in 5. Blood cultures were negative 72 hours after the first dose of the combination in all cases. The success rate was 69%, and only 1 of 5 deaths was related to the MRSA infection. Although the combination was safe in most patients (94%), a patient with liver cirrhosis died of multiorgan failure secondary to sodium overload. There were no episodes of breakthrough bacteremia or relapse. Fosfomycin plus imipenem was an effective and safe combination when used as rescue therapy for complicated MRSA bloodstream infections and deserves further clinical evaluation as initial therapy in these infections. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  11. Considerations about an administrative ''margin of prognosis''

    International Nuclear Information System (INIS)

    Tettinger, P.J.

    1982-01-01

    The investigation is concerned with the limitations of certain judicial concepts, and the descretion of the appropriate administrative authorities to interpret them, especially in the area of necessary precautionary measures with regard to nuclear power plants safety. Thereby the question arises, whether by interpreting undefined judicial concepts (such as ''the status of science and technology'', e.g. section 1 sub-section 2, number 3 of the Atomic Energy Law), administrative authorities should be given a flexible margin of judgement which could not be examined, by the administrative courts, especially in view of risk analysis and risk assessments. Diverging opinions in legal literature and the administration of justice will be presented and critically analyzed. The author argues for an integral administrative procedure. Controlling the licensing of nuclear power plants, which - if need be - should only be limited by a ''plausibility control'' in cases where several security-safety related technical solutions appear acceptable. (WBI) [de

  12. ANALYSIS OF LABOUR ACCIDENTS DUE TO ROCK FALL EVENTS IN CUTTING FACE OF TUNNEL AND STUDY OF THE COUNTERMEASURES FOR SAFETY

    Science.gov (United States)

    Kikkawa, Naotaka; Itoh, Kazuya; Hori, Tomohito; Tamate, Satoshi; Toyosawa, Yasuo

    In this paper, we analysed the labour accidents which had casualties due to rock fall events in the headings of tunnel and cleared the condition of the occurrence. It was clearly revealed that the accidents mostly happened when the workers mounted the explosive and the steel arch in the headings of the mountain tunnel. In addition, the dimension of the rocks fallen were averagely 0.6m diameter, it was not so much large. Therefore, the countermeasures based on both soft and hard faces would be useful and effective, such as the displacement measurement of a cutting face of tunnel, securing the sufficient lights to observe the cutting face, boring for drainage and shotcreting in a heading of tunnel.

  13. Tectonic signatures on active margins

    Science.gov (United States)

    Hogarth, Leah Jolynn

    High-resolution Compressed High-Intensity Radar Pulse (CHIRP) surveys offshore of La Jolla in southern California and the Eel River in northern California provide the opportunity to investigate the role of tectonics in the formation of stratigraphic architecture and margin morphology. Both study sites are characterized by shore-parallel tectonic deformation, which is largely observed in the structure of the prominent angular unconformity interpreted as the transgressive surface. Based on stratal geometry and acoustic character, we identify three sedimentary sequences offshore of La Jolla: an acoustically laminated estuarine unit deposited during early transgression, an infilling or "healing-phase" unit formed during the transgression, and an upper transparent unit. The estuarine unit is confined to the canyon edges in what may have been embayments during the last sea-level rise. The healing-phase unit appears to infill rough areas on the transgressive surface that may be related to relict fault structures. The upper transparent unit is largely controlled by long-wavelength tectonic deformation due to the Rose Canyon Fault. This unit is also characterized by a mid-shelf (˜40 m water depth) thickness high, which is likely a result of hydrodynamic forces and sediment grain size. On the Eel margin, we observe three distinct facies: a seaward-thinning unit truncated by the transgressive surface, a healing-phase unit confined to the edges of a broad structural high, and a highly laminated upper unit. The seaward-thinning wedge of sediment below the transgressive surface is marked by a number of channels that we interpret as distributary channels based on their morphology. Regional divergence of the sequence boundary and transgressive surface with up to ˜8 m of sediment preserved across the interfluves suggests the formation of subaerial accommodation during the lowstand. The healing-phase, much like that in southern California, appears to infill rough areas in the

  14. A Phase 3, Randomized, Double-Blind, Multicenter Study To Evaluate the Safety and Efficacy of Intravenous Iclaprim versus Vancomycin for Treatment of Acute Bacterial Skin and Skin Structure Infections Suspected or Confirmed To Be Due to Gram-Positive Pathogens (REVIVE-2 Study).

    Science.gov (United States)

    Holland, Thomas L; O'Riordan, William; McManus, Alison; Shin, Elliot; Borghei, Ali; File, Thomas M; Wilcox, Mark H; Torres, Antoni; Dryden, Matthew; Lodise, Thomas; Oguri, Toyoko; Corey, G Ralph; McLeroth, Patrick; Shukla, Rajesh; Huang, David B

    2018-05-01

    Iclaprim is a novel diaminopyrimidine antibiotic that may be an effective and safe treatment for serious skin infections. The safety and effectiveness of iclaprim were assessed in a global phase 3, double-blind, randomized, active-controlled trial. Six hundred thirteen adults with acute bacterial skin and skin structure infections (ABSSSIs) suspected or confirmed to be due to Gram-positive pathogens were randomized to iclaprim (80 mg) or vancomycin (15 mg/kg of body weight), both of which were administered intravenously every 12 h for 5 to 14 days. The primary endpoint was a ≥20% reduction in lesion size compared with that at the baseline at 48 to 72 h after the start of administration of study drug in the intent-to-treat population. Among patients randomized to iclaprim, 78.3% (231 of 295) met this primary endpoint, whereas 76.7% (234 of 305) of those receiving vancomycin met this primary endpoint (difference, 1.58%; 95% confidence interval, -5.10% to 8.26%). This met the prespecified 10% noninferiority margin. Iclaprim was well tolerated, with most adverse events being categorized as mild. In conclusion, iclaprim was noninferior to vancomycin in this phase 3 clinical trial for the treatment of acute bacterial skin and skin structure infections. On the basis of these results, iclaprim may be an efficacious and safe treatment for skin infections suspected or confirmed to be due to Gram-positive pathogens. (This trial has been registered at ClinicalTrials.gov under identifier NCT02607618.). Copyright © 2018 American Society for Microbiology.

  15. Influence of Crack Morphology on Leak Before Break Margins

    International Nuclear Information System (INIS)

    Weilin Zang

    2007-11-01

    The purpose of the project is to evaluate the deterministic LBB-margins for different pipe systems in a Swedish PWR-plant and using different crack morphology parameters. Results: - The influence of crack morphology on Leak Before Break (LBB) margins is studied. The subject of the report is a number of LBB-submittals to SKI where deterministic LBB-margins are reported. These submittals typically uses a surface roughness of 0.0762 mm (300 microinch) and number of turns equal to zero and an in-house code for the leak rate evaluations. The present report has shown that these conditions give the largest LBB-margins both in terms of the quotient between the critical crack length and the leakage crack size and for the leak rate margin. - Crack morphology parameters have a strong influence on the leak rate evaluations. Using the SQUIRT code and more recent recommendations for crack morphology parameters, it is shown that in many cases the evaluated margins, using 1 gpm as the reference leak rate detection limit, are below the safety factor of 2 on crack size and 10 on leak rate, which is generally required for LBB approval. - The effect of including weld residual stresses on the LBB margins is also investigated. It is shown that for the two examples studied, weld residual stresses were important for the small diameter thin wall pipe whereas it was negligible for the large diameter thick wall pipe which had a self-balanced weld residual stress distribution

  16. Study on the estimation of safety margin of piping system against seismic loading. 1st report, damage observations of the straight pipes subjected to cyclic load amplitudes of various levels

    International Nuclear Information System (INIS)

    Nakamura, Izumi; Otani, Akihito; Shiratori, Masaki

    2010-01-01

    Fatigue failure accompanied by ratchet deformation is well known as one of the failure modes of pressurized pipes under high-level cyclic load. In this research, the process of failure of such pipes was investigated based on the experimental result in which a straight pipe failed by repeatedly increasing cyclic input displacement amplitude in stages. The strain behavior, moment-deflection relationship, and observed damage were compared with the stress level used in the seismic design of the piping system. As a result, no significant damage was observed and the moment-deflection relationship remained almost linear within the primary stress limit of 3S m , although the strain showed elastic-plastic behavior at some measurement points. In the experiment, damage was observed at the applied load levels of approximately 5S m of the primary stress, and 0.15 and more of the fatigue damage index, i.e., the usage factor based on the design. The test results showed that there is a certain time margin before failure occurs to actual piping systems, compared with its designed stress limitation. (author)

  17. Bowel perforation due to break and distal passage of the safety ring of an adjustable intra-gastric balloon: A potentially life threatening situation.

    Science.gov (United States)

    Al-Zubaidi, Ali M; Alghamdi, Hassan U; Alzobydi, Abdu H; Dhiloon, Irshad A; Qureshi, Laeeque A

    2015-04-16

    A 45-year-old man of Middle Eastern origin, morbid obese, with a body mass index of 39 had an intra-gastric balloon, filled with 500 mL of saline/methylene blue and intended as definite therapy, inserted some 8 wk previously. He was admitted to the emergency department with abdominal cramps. An ultrasound of the abdomen was performed in ER which confirmed the balloon to be in place without any abnormality. He was discharged home on symptomatic medication. Patient remains symptomatic therefore he reported back to ER 2 d later. Computed tomography scan was performed this time for further evaluation which revealed a metallic ring present in the small bowel while the intra-gastric balloon was in its proper position. There was no clinical or radiological sign of intestinal obstruction. Patient was hospitalized for observation and conservative management. The following night, patient experienced sudden and severe abdominal pain, therefore an X-ray of the abdomen in erect position was done, which showed free air under the right dome of diaphragm. Patient was transferred to O.R for emergency laparotomy. There were two small perforations identified at the site of the metallic ring entrapment. The ring was removed and the perforations were repaired. Due to increasing prevalence of obesity and advances in modalities for its management, physicians should be aware of treatment options, their benefits, complications and clinical presentation of the known complications. Physicians need to be updated to approach these complications within time, to avoid life-threatening situations caused by these appliances.

  18. Learning Convex Inference of Marginals

    OpenAIRE

    Domke, Justin

    2012-01-01

    Graphical models trained using maximum likelihood are a common tool for probabilistic inference of marginal distributions. However, this approach suffers difficulties when either the inference process or the model is approximate. In this paper, the inference process is first defined to be the minimization of a convex function, inspired by free energy approximations. Learning is then done directly in terms of the performance of the inference process at univariate marginal prediction. The main ...

  19. Steel Industry Marginal Opportunity Analysis

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2005-09-01

    The Steel Industry Marginal Opportunity Analysis (PDF 347 KB) identifies opportunities for developing advanced technologies and estimates both the necessary funding and the potential payoff. This analysis determines what portion of the energy bandwidth can be captured through the adoption of state-of-the-art technology and practices. R&D opportunities for addressing the remainder of the bandwidth are characterized and plotted on a marginal opportunity curve.

  20. Veblen effect, marginal utility of money, and money illusion

    OpenAIRE

    Malakhov, Sergey

    2013-01-01

    The paper discovers microeconomic mechanism of Veblen effect as well as of Giffen case as results of the negative marginal utility of money. The marginal utility of consumption also becomes negative. The total consumption-leisure utility is increased due to the increase in leisure time. This overall effect results in the phenomenon of money illusion on the macroeconomic level. This general effect has deep historical and institutional grounds and, in order to minimize its disequilibrium econom...

  1. Univariate decision tree induction using maximum margin classification

    OpenAIRE

    Yıldız, Olcay Taner

    2012-01-01

    In many pattern recognition applications, first decision trees are used due to their simplicity and easily interpretable nature. In this paper, we propose a new decision tree learning algorithm called univariate margin tree where, for each continuous attribute, the best split is found using convex optimization. Our simulation results on 47 data sets show that the novel margin tree classifier performs at least as good as C4.5 and linear discriminant tree (LDT) with a similar time complexity. F...

  2. Thermal margin model for transition core of KSNP

    International Nuclear Information System (INIS)

    Nahm, Kee Yil; Lim, Jong Seon; Park, Sung Kew; Chun, Chong Kuk; Hwang, Sun Tack

    2004-01-01

    The PLUS7 fuel was developed with mixing vane grids for KSNP. For the transition core partly loaded with the PLUS7 fuels, the procedure to set up the optimum thermal margin model of the transition core was suggested by introducing AOPM concept into the screening method which determines the limiting assembly. According to the procedure, the optimum thermal margin model of the first transition core was set up by using a part of nuclear data for the first transition and the homogeneous core with PLUS7 fuels. The generic thermal margin model of PLUS7 fuel was generated with the AOPM of 138%. The overpower penalties on the first transition core were calculated to be 1.0 and 0.98 on the limiting assembly and the generic thermal margin model, respectively. It is not usual case to impose the overpower penalty on reload cores. It is considered that the lack of channel flow due to the difference of pressure drop between PLUS7 and STD fuels results in the decrease of DNBR. The AOPM of the first transition core is evaluated to be about 135% by using the optimum generic thermal margin model which involves the generic thermal margin model and the total overpower penalty. The STD fuel is not included among limiting assembly candidates in the second transition core, because they have much lower pin power than PLUS7 fuels. The reduced number of STD fuels near the limiting assembly candidates the flow from the limiting assembly to increase the thermal margin for the second transition core. It is expected that cycle specific overpower penalties increase the thermal margin for the transition core. Using the procedure to set up the optimum thermal margin model makes sure that the enhanced thermal margin of PLUS7 fuel can be sufficiently applied to not only the homogeneous core but also the transition core

  3. Nuclear safety in France

    International Nuclear Information System (INIS)

    Tanguy, P.

    1979-01-01

    A brief description of the main safety aspects of the French nuclear energy programme and of the general safety organization is followed by a discussion on the current thinking in CEA on some important safety issues. As far as methodology is concerned, the use of probabilistic analysis in the licensing procedure is being extensively developed. Reactor safety research is aimed at a better knowledge of the safety margins involved in the present designs of both PWRs and LMFBRs. A greater emphasis should be put during the next years in the safety of the nuclear fuel cycle installations, including waste disposals. Finally, it is suggested that further international cooperation in the field of nuclear safety should be developed in order to insure for all countries the very high safety level which has been achieved up till now. (author)

  4. Studies on correlation of positive surgical margin with clinicopathological factors and prognoses in breast conserving surgery

    International Nuclear Information System (INIS)

    Nishimura, Reiki; Nagao, Kazuharu; Miyayama, Haruhiko

    1999-01-01

    Out of 484 cases with breast conserving surgery between April 1989 and March 1999, surgical procedures of 34 cases were changed to total mastectomy due to positive surgical margins. In this study we evaluated a clinical significance of surgical margin in relation to clinicopathological factors and prognoses. Ninety-nine cases (20.5%) had positive margins that were judged when cancer cells existed within 5 mm from margin. In multivariate analysis of factors for surgical margin, EIC-comedo status, ly, located site, proliferative activity, and age were significant and independent factors. Regarding local recurrence, positive margin, age, ER and proliferative activity were significant factors in multivariate analysis, especially in cases not receiving postoperative radiation therapy. Radiation therapy may be beneficial for patients with positive surgical margin. And patients with breast recurrence alone had significantly higher survival rates. Therefore, it is suggested that surgical margin may not reflect survival, although it is a significant factor for local recurrence. (author)

  5. Studies on correlation of positive surgical margin with clinicopathological factors and prognoses in breast conserving surgery

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Reiki; Nagao, Kazuharu; Miyayama, Haruhiko [Kumamoto City Hospital (Japan)

    1999-09-01

    Out of 484 cases with breast conserving surgery between April 1989 and March 1999, surgical procedures of 34 cases were changed to total mastectomy due to positive surgical margins. In this study we evaluated a clinical significance of surgical margin in relation to clinicopathological factors and prognoses. Ninety-nine cases (20.5%) had positive margins that were judged when cancer cells existed within 5 mm from margin. In multivariate analysis of factors for surgical margin, EIC-comedo status, ly, located site, proliferative activity, and age were significant and independent factors. Regarding local recurrence, positive margin, age, ER and proliferative activity were significant factors in multivariate analysis, especially in cases not receiving postoperative radiation therapy. Radiation therapy may be beneficial for patients with positive surgical margin. And patients with breast recurrence alone had significantly higher survival rates. Therefore, it is suggested that surgical margin may not reflect survival, although it is a significant factor for local recurrence. (author)

  6. Evaluation of LBB margin of nuclear piping systems

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Il Soon; Kim, Ji Hyeon; Oh, Yeong Jin; Lim, Jun [Seoul Nationl Univ., Seoul (Korea, Republic of); Kim, In Seob; Kim, Yong Seon; Lee, Joo Seok [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1999-04-15

    Most of previous elastic-plastic fracture studies for LBB assessment of low alloy steel piping have been focused on base metals and weld metals. In contract, the heat affected zone of welded pipe has not been studied in detail primarily because the size of heat affected zone in welded pipe os too small to make specimens for mechanical properties measurement. When structural members are joined by welding, the base metal is heated to its melting point and then cooled rapidly. As a result of this very severe thermal cycle, mechanical properties in the heat affected zone can be degraded by grain coarsening, the precipitation and the segregation of trace impurities. In this study, a thermal and microstructural analysis is performed, and mechanical properties are measured for the weld heat affected zone of SA106Gr.C low allowed piping steel. In addition, inter critical annealing treatment. in two-phase (alpha+gamma) region was performed to investigate the possibilities of improving the toughness and reducing dynamic strain aging (DSA) susceptibility for giving allowable LBB safety margins. From the results, intercritical annealing is shown to give a smaller ductility loss due to DSA than the case of as-received material. Furthermore, the intercritical annealing was able to increase the impact toughness by a factor of 1.5 compared to the as-received material.

  7. Evaluation of LBB margin of nuclear piping systems

    International Nuclear Information System (INIS)

    Hwang, Il Soon; Kim, Ji Hyeon; Oh, Yeong Jin; Lim, Jun; Kim, In Seob; Kim, Yong Seon; Lee, Joo Seok

    1999-04-01

    Most of previous elastic-plastic fracture studies for LBB assessment of low alloy steel piping have been focused on base metals and weld metals. In contract, the heat affected zone of welded pipe has not been studied in detail primarily because the size of heat affected zone in welded pipe os too small to make specimens for mechanical properties measurement. When structural members are joined by welding, the base metal is heated to its melting point and then cooled rapidly. As a result of this very severe thermal cycle, mechanical properties in the heat affected zone can be degraded by grain coarsening, the precipitation and the segregation of trace impurities. In this study, a thermal and microstructural analysis is performed, and mechanical properties are measured for the weld heat affected zone of SA106Gr.C low allowed piping steel. In addition, inter critical annealing treatment. in two-phase (alpha+gamma) region was performed to investigate the possibilities of improving the toughness and reducing dynamic strain aging (DSA) susceptibility for giving allowable LBB safety margins. From the results, intercritical annealing is shown to give a smaller ductility loss due to DSA than the case of as-received material. Furthermore, the intercritical annealing was able to increase the impact toughness by a factor of 1.5 compared to the as-received material

  8. Efficacy and safety of two doses of Norditropin® (somatropin) in short stature due to Noonan syndrome: a 2-year randomized, double-blind, multicenter trial in Japanese patients.

    Science.gov (United States)

    Ozono, Keiichi; Ogata, Tsutomu; Horikawa, Reiko; Matsubara, Yoichi; Ogawa, Yoshihisa; Nishijima, Keiji; Yokoya, Susumu

    2018-02-26

    This randomized double-blind multicenter trial (NCT01927861) evaluated the growth-promoting effect and safety of Norditropin ® (NN220; somatropin) in Japanese children with short stature due to Noonan syndrome. Prepubertal children aged 3-Noonan syndrome were randomized to receive GH 0.033 mg/kg/day (n = 25, mean age 6.57 years, 11 females) or 0.066 mg/kg/day (n = 26, mean age 6.06 years, eight females) for 104 weeks. Change in height standard deviation score (HSDS) from baseline was analyzed based on an ANCOVA model. Baseline HSDS was -3.24. Estimated change in HSDS [95% CI] after 104 weeks' treatment was 0.84 [0.66, 1.02] and 1.47 [1.29, 1.64] for the lower and higher doses, respectively; estimated mean difference 0.63 [0.38, 0.88], p Noonan syndrome, with a favorable safety profile. The effect was greater with 0.066 mg/kg/day compared with 0.033 mg/kg/day.

  9. The basic principles for the assessment of occupational exposure due to intakes of radionuclides (The most important indirect methods used in the Protection and Safety Dept. for internal occupational exposure monitoring)

    International Nuclear Information System (INIS)

    Kharita, M. H.; Sakhita, K.

    2009-05-01

    This study shows the basic principles for the assessment of occupational exposure due to intakes of radionuclides in order to calculate the committed effective dose of each radionuclide separately. We also discussed when the routine monitoring of workers becomes useful and when the workplace monitoring is better than workers monitoring. In addition, this study contains the details of four indirect methods as they are validated in the protection and safety department, and their names are: Determination the concentration of total uranium by using fluorimetry technique, Determination the activity of two uranium isotopes 238 and 234, The activity of Polonium 210, and the activity of Radium 226 by using alpha spectrometry for urine samples collected from workers occupationally exposed to this isotope. (author)

  10. The Marginal Source of Finance

    OpenAIRE

    Lindhe, Tobias

    2002-01-01

    This paper addresses the ongoingdebate on which view of equity, traditional or new, that best describes firm behavior. According to the traditional view, the marginal source of finance is new equity, whereas under to the new view, marginal financing comes from retained earnings. In the theoretical part, we set up a model where the firm faces a cost of adjusting the dividend level because of an aggravated free cash flow problem. The existence of such a cost - which has been used in arguing the...

  11. Single-Center Experience Using Marginal Liver Grafts in Korea.

    Science.gov (United States)

    Park, P-J; Yu, Y-D; Yoon, Y-I; Kim, S-R; Kim, D-S

    2018-05-01

    Liver transplantation (LT) is an established therapeutic modality for patients with end-stage liver disease. The use of marginal donors has become more common worldwide due to the sharp increase in recipients, with a consequent shortage of suitable organs. We analyzed our single-center experience over the last 8 years in LT to evaluate the outcomes of using so-called "marginal donors." We retrospectively analyzed the database of all LTs performed at our institution from 2009 to 2017. Only patients undergoing deceased-donor LTs were analyzed. Marginal grafts were defined as livers from donors >60 years of age, livers from donors with serum sodium levels >155 mEq, graft steatosis >30%, livers with cold ischemia time ≥12 hours, livers from donors who were hepatitis B or C virus positive, livers recovered from donation after cardiac death, and livers split between 2 recipients. Patients receiving marginal grafts (marginal group) were compared with patients receiving standard grafts (standard group). A total of 106 patients underwent deceased-donor LT. There were 55 patients in the standard group and 51 patients in the marginal group. There were no significant differences in terms of age, sex, Model for End-Stage Liver Disease score, underlying liver disease, presence of hepatocellular carcinoma, and hospital stay between the 2 groups. Although the incidence of acute cellular rejection, cytomegalovirus infection, and postoperative complications was similar between the 2 groups, the incidence of early allograft dysfunction was higher in the marginal group. With a median follow-up of 26 months, the 1-, 3-, and 5-year overall and graft (death-censored) survivals in the marginal group were 85.5%, 75%, and 69.2% and 85.9%, 83.6%, and 77.2%, respectively. Patient overall survival and graft survival (death-censored) were significantly lower in the marginal group (P = .023 and P = .048, respectively). On multivariate analysis, receiving a marginal graft (hazard ratio [HR

  12. Safety considerations of PWR's

    International Nuclear Information System (INIS)

    Arnold, W.H. Jr.

    1977-01-01

    The safety of the central station pressurized water reactor is well established and substantiated by its excellent operating record. Operating data from 55 reactors of this type have established a record of safe operating history unparalleled by any modern large scale industry. The 186 plants under construction require a continuing commitment to maintain this outstanding record. The safety of the PWR has been further verified by the recently completed Reactor Safety Study (''Rasmussen'' Report). Not only has this study confirmed the exceptionally low risk associated with PWR operation, it has also introduced a valuable new tool in the decision making process. PWR designs, utilizing the philosophy of defense in depth, provide the bases for evaluating margins of safety. The design of the reactor coolant system, the containment system, emergency core cooling system and other related systems and components provide substantial margins of safety under both normal and postulated accident conditions even considering simultaneous effects of earthquakes and other environmental phenomena. Margins of safety in the assessment of various postulated accident conditions, with emphasis on the postulated loss of reactor coolant accident (LOCA), have been evaluated in depth as exemplified by the comprehensive ECCS rulemaking hearings followed by imposition of very conservative Nuclear Regulatory Commission requirements. When evaluated on an engineering best estimate approach, the significant margins to safety for a LOCA become more apparent. Extensive test programs have also substantiated margins to safety limits. These programs have included both separate effects and systems tests. Component testing has also been performed to substantiate performance levels under adverse combinations of environmental stress. The importance of utilizing past experience and of optimizing the deployment of incremental resources is self evident. Recent safety concerns have included specific areas such

  13. Characterizing Convexity of Games using Marginal Vectors

    NARCIS (Netherlands)

    van Velzen, S.; Hamers, H.J.M.; Norde, H.W.

    2003-01-01

    In this paper we study the relation between convexity of TU games and marginal vectors.We show that if specfic marginal vectors are core elements, then the game is convex.We characterize sets of marginal vectors satisfying this property, and we derive the formula for the minimum number of marginal

  14. Operational margin monitoring system for boiling water reactor power plants

    International Nuclear Information System (INIS)

    Fukutomi, S.; Takigawa, Y.

    1992-01-01

    This paper reports on an on-line operational margin monitoring system which has been developed for boiling water reactor power plants to improve safety, reliability, and quality of reactor operation. The system consists of a steady-state core status prediction module, a transient analysis module, a stability analysis module, and an evaluation and guidance module. This system quantitatively evaluates the thermal margin during abnormal transients as well as the stability margin, which cannot be evaluated by direct monitoring of the plant parameters, either for the current operational state or for a predicted operating state that may be brought about by the intended operation. This system also gives operator guidance as to appropriate or alternate operations when the operating state has or will become marginless

  15. Safety issues of botanicals and botanical preparations in functional foods

    International Nuclear Information System (INIS)

    Kroes, R.; Walker, R.

    2004-01-01

    Although botanicals have played a role in the marketing of health products for ages, there is an increased interest today due to their perceived health benefits. Not only do consumers increasingly take charge of their health, but the scientific information and understanding of the beneficial health effects of bioactive substances in food, functional foods and food supplements have improved. Increasing use of these products has also led to concerns about their actual safety. Recorded cases of intoxications have triggered such concerns. The safety assessment of these substances is complicated by, amongst others, the variability of composition. Furthermore, consumption of such functional products is expected to produce physiological effects, which may lead to low margins of safety as the margin between exposure of such products and the safe level of intake are likely to be small. The safety assessment of botanicals and botanical preparations in food and food supplement should at least involve: - the characterisation and quality of the material, its quality control; - the intended use and consequent exposure; - history of use and exposure; - product comparison(s); - toxicological information gathering; - Risk characterisation/safety assessment; As a guidance tool, a decision tree approach is proposed to assist in determining the extent of data requirements based on the nature of the such product. This guidance tool in safety assessment was developed by an expert group of the International Life Sciences Institute (ILSI), European Branch, and is currently in press. In this paper a summarised version of this tool is presented

  16. Marginality and Variability in Esperanto.

    Science.gov (United States)

    Brent, Edmund

    This paper discusses Esperanto as a planned language and refutes three myths connected to it, namely, that Esperanto is achronical, atopical, and apragmatic. The focus here is on a synchronic analysis. Synchronic variability is studied with reference to the structuralist determination of "marginality" and the dynamic linguistic…

  17. Ethnographies of marginality [Review article

    NARCIS (Netherlands)

    Beuving, J.J.

    2016-01-01

    Africanist discourse today displays a strong, widespread and growing sense of optimism about Africa's economic future. After decades of decline and stagnation in which Africa found itself reduced to the margins of the global economic stage, upbeat Afro-optimism seems fully justified. One only needs

  18. Profit margins in Japanese retailing

    NARCIS (Netherlands)

    J.C.A. Potjes; A.R. Thurik (Roy)

    1993-01-01

    textabstractUsing a rich data source, we explain differences and developments in profit margins of medium-sized stores in Japan. We conclude that the protected environment enables the retailer to pass on all operating costs to the customers and to obtain a relatively high basic income. High service

  19. Pushing the Margins of Responsibility

    DEFF Research Database (Denmark)

    Santoni de Sio, Filippo; Di Nucci, Ezio

    2018-01-01

    David Shoemaker has claimed that a binary approach to moral responsibility leaves out something important, namely instances of marginal agency, cases where agents seem to be eligible for some responsibility responses but not others. In this paper we endorse and extend Shoemaker’s approach by pres...

  20. Removing unreasonable conservatisms in DOE safety analysis

    International Nuclear Information System (INIS)

    BISHOP, G.E.

    1999-01-01

    While nuclear safety analyses must always be conservative, invoking excessive conservatisms does not provide additional margins of safety. Rather, beyond a fairly narrow point, conservatisms skew a facility's true safety envelope by exaggerating risks and creating unreasonable bounds on what is required for safety. The conservatism has itself become unreasonable. A thorough review of the assumptions and methodologies contained in a facility's safety analysis can provide substantial reward, reducing both construction and operational costs without compromising actual safety

  1. Safety system function trends

    International Nuclear Information System (INIS)

    Johnson, C.

    1989-01-01

    This paper describes research to develop risk-based indicators of plant safety performance. One measure of the safety-performance of operating nuclear power plants is the unavailability of important safety systems. Brookhaven National Laboratory and Science Applications International Corporation are evaluating ways to aggregate train-level or component-level data to provide such an indicator. This type of indicator would respond to changes in plant safety margins faster than the currently used indicator of safety system unavailability (i.e., safety system failures reported in licensee event reports). Trends in the proposed indicator would be one indication of trends in plant safety performance and maintenance effectiveness. This paper summarizes the basis for such an indicator, identifies technical issues to be resolved, and illustrates the potential usefullness of such indicators by means of computer simulations and case studies

  2. Seismic margin analysis technique for nuclear power plant structures

    International Nuclear Information System (INIS)

    Seo, Jeong Moon; Choi, In Kil

    2001-04-01

    In general, the Seismic Probabilistic Risk Assessment (SPRA) and the Seismic Margin Assessment(SAM) are used for the evaluation of realistic seismic capacity of nuclear power plant structures. Seismic PRA is a systematic process to evaluate the seismic safety of nuclear power plant. In our country, SPRA has been used to perform the probabilistic safety assessment for the earthquake event. SMA is a simple and cost effective manner to quantify the seismic margin of individual structural elements. This study was performed to improve the reliability of SMA results and to confirm the assessment procedure. To achieve this goal, review for the current status of the techniques and procedures was performed. Two methodologies, CDFM (Conservative Deterministic Failure Margin) sponsored by NRC and FA (Fragility Analysis) sponsored by EPRI, were developed for the seismic margin review of NPP structures. FA method was originally developed for Seismic PRA. CDFM approach is more amenable to use by experienced design engineers including utility staff design engineers. In this study, detailed review on the procedures of CDFM and FA methodology was performed

  3. Operational safety at the FFTF

    International Nuclear Information System (INIS)

    Baird, Q.L.; Hagan, J.W.; Seeman, S.E.; Baker, S.M.

    1981-02-01

    An extensive operational nuclear safety program has been an integral part of the design, startup, and initial operating phases of the Fast Flux Test Facility (FFTF). During the design and construction of the facility, a program of independent safety overviews and analyses assured the provision of responsible safety margins within the plant, protective systems, and engineered safety features for protection of the public, operating staff, and the facility. The program is continuing through surveillance of operations to verify continued adherence to the established operating envelope and for timely identification of any trends potentially adverse to those margins. Experience from operation of FFTF is being utilized in the development of enhanced operational nuclear safety aids for application in follow-on breeder reactor power systems. The commendable plant and personnel safety experiences of FFTF through its startup and ascension to full power demonstrate the overall effectiveness of the FFTF operational nuclear safety program

  4. Contributions to knowledge of the continental margin of Uruguay. Uruguayan continental margin: Physiographic and seismic analysis

    International Nuclear Information System (INIS)

    Preciozzi, F

    2014-01-01

    This work is about the kind of continental margins such as a )Atlantic type passive margins which can be hard or soft b) An active or Pacific margins that because of the very frequent earthquakes develop a morphology dominated by tectonic processes. The Uruguayan continental margin belongs to a soft Atlantic margin

  5. Volcanic passive margins: another way to break up continents.

    Science.gov (United States)

    Geoffroy, L; Burov, E B; Werner, P

    2015-10-07

    Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle.

  6. Indigenous women's voices: marginalization and health.

    Science.gov (United States)

    Dodgson, Joan E; Struthers, Roxanne

    2005-10-01

    Marginalization may affect health care delivery. Ways in which indigenous women experienced marginalization were examined. Data from 57 indigenous women (18 to 65 years) were analyzed for themes. Three themes emerged: historical trauma as lived marginalization, biculturalism experienced as marginalization, and interacting within a complex health care system. Experienced marginalization reflected participants' unique perspective and were congruent with previous research. It is necessary for health care providers to assess the detrimental impact of marginalization on the health status of individuals and/or communities.

  7. Barriers to Education for the Marginalized Adult Learner

    Science.gov (United States)

    Flynn, Sarah; Brown, Jason; Johnson, Andrew; Rodger, Susan

    2011-01-01

    This qualitative study examines barriers to adult education by the marginalized adult learner. We adopted an inclusive approach by interviewing potential adult learners who had not participated in adult education programs due to illiteracy. Five overlapping themes related to barriers emerged and were categorized as: family values and…

  8. Subsystem response analysis for the Seismic Safety Margins Research Program

    International Nuclear Information System (INIS)

    Chuang, T.Y.

    1981-01-01

    A review of the state-of-the-art of seismic qualification methods of subsystem has been completed. This task assesses the accuracy of seismic analysis techniques to predict dynamic response, and also identifies and quantifies sources of random and modeling undertainty in subsystem response determination. The subsystem has been classified as two categories according to the nature of support: multiply supported subsystems (e.g., piping systems) and singly supported subsystems (e.g., pumps, turbines, electrical control panels, etc.). The mutliply supported piping systems are analyzed by multisupport input time history method. The input motions are the responses of major structures. The dynamic models of the subsystems identified by the event/fault tree are created. The responses calculated by multisupport input time history method are consistent with the fragility parameters. These responses are also coordinated with the event/fault tree description. The subsystem responses are then evaluated against the fragility curves of components and systems and incorporated in the event/fault tree analysis. (orig./HP)

  9. Exploring the Safety Margin in Current Guidelines for Electromagnetic Exposure

    NARCIS (Netherlands)

    F. Adibzadeh (Fatemeh)

    2017-01-01

    markdownabstractExposure to radio-frequency (RF) electromagnetic fields (EMF) is unavoidable in today's modern life. This exposure is growing mainly because of rapid growth in telecommunication systems. Awareness of the possible risks of exposure to EMF has raised public concern. To avoid any

  10. Subsystem response review. Seismic safety margins research program

    International Nuclear Information System (INIS)

    Kennedy, R.P.; Campbell, R.D.; Wesley, D.A.; Kamil, H.; Gantayat, A.; Vasudevan, R.

    1981-07-01

    A study was conducted to document the state of the art in seismic qualification of nuclear power plant components and subsystems by analysis and testing and to identify the sources and magnitude of the uncertainties associated with analysis and testing methods. The uncertainties are defined in probabilistic terms for use in probabilistic seismic risk studies. Recommendations are made for the most appropriate subsystem response analysis methods to minimize response uncertainties. Additional studies, to further quantify testing uncertainties, are identified. Although the general effect of non-linearities on subsystem response is discussed, recommendations and conclusions are based principally on linear elastic analysis and testing models. (author)

  11. Marginalism, quasi-marginalism and critical phenomena in micellar solutions

    International Nuclear Information System (INIS)

    Reatto, L.

    1986-01-01

    The observed nonuniversal critical behaviour of some micellar solutions is interpreted in terms of quasi-marginalism, i.e. the presence of a coupling which scales with an exponent very close to the spatial dimensionality. This can give rise to a preasymptotic region with varying effective critical exponents with a final crossover to the Ising ones. The reduced crossover temperature is estimated to be below 10 -6 . The exponents β and γ measured in C 12 e 5 are in good agreement with the scaling law expected to hold for the effective exponents. The model considered by Shnidman is found unable to explain the nonuniversal critical behaviour

  12. Biological impact of geometric uncertainties: what margin is needed for intra-hepatic tumors?

    International Nuclear Information System (INIS)

    Kuo, Hsiang-Chi; Liu, Wen-Shan; Wu, Andrew; Mah, Dennis; Chuang, Keh-Shih; Hong, Linda; Yaparpalvi, Ravi; Guha, Chandan; Kalnicki, Shalom

    2010-01-01

    To evaluate and compare the biological impact on different proposed margin recipes for the same geometric uncertainties for intra-hepatic tumors with different tumor cell types or clinical stages. Three different margin recipes based on tumor motion were applied to sixteen IMRT plans with a total of twenty two intra-hepatic tumors. One recipe used the full amplitude of motion measured from patients to generate margins. A second used 70% of the full amplitude of motion, while the third had no margin for motion. The biological effects of geometric uncertainty in these three situations were evaluated with Equivalent Uniform Doses (EUD) for various survival fractions at 2 Gy (SF 2 ). There was no significant difference in the biological impact between the full motion margin and the 70% motion margin. Also, there was no significant difference between different tumor cell types. When the margin for motion was eliminated, the difference of the biological impact was significant among different cell types due to geometric uncertainties. Elimination of the motion margin requires dose escalation to compensate for the biological dose reduction due to the geometric misses during treatment. Both patient-based margins of full motion and of 70% motion are sufficient to prevent serious dosimetric error. Clinical implementation of margin reduction should consider the tumor sensitivity to radiation

  13. Margins in Swedish district heating systems; Marginaler i Fjaerrvaermesystem

    Energy Technology Data Exchange (ETDEWEB)

    Selinder, Patrik; Zinko, Heimo [ZW Energiteknik AB, Nykoeping (Sweden)

    2003-03-01

    It can be assumed on good reasons that the Swedish district heating nets are designed with relatively large margins concerning the transportable power. This is done historically to be able to transport the necessary power that can be called for on the coldest winter days but which occur rarely and also due to the former (until 2001) applied recommendations for the dimensioning of hot water flows. The aim of this project was to investigate the possibilities of reducing the connecting power to customers, both from a technical and from the customer point of view. The heating system of a building in Sweden is normally dimensioned according to a certain outdoor air temperature (DUT in Swedish). According to the Swedish Building Code, DUT20 is defined for a given location in such a way that if the heating system is designed for this temperature, the room temperature is allowed to decrease by 3 deg C in the average once in 20 years. That means that for economical reasons, a power deficiency is accounted for in the case of strong cold. The value of DUT is depending on the thermal inertia of the building. Buildings with high thermal inertia can have a higher DUT and vice versa. A reduced system size can in principle mean smaller size of pipes and consumer substations and more power available for additional customers to be connected. In principle, that means a more profitable district heating operation. Besides costs, another problem with oversized capacities are possible operational problems due to slow dynamic system responses, for instance at restarting occasions after a pump stop. A smaller valve size will result in a better system dynamic and may result in a more compliant system operation and increased delivery quality. By choosing just right DUT for every building and abandoning safety margins, it is shown in the report that the connecting power can be reduced in especially medium light to heavy buildings with larger time constants. However, this also means that the

  14. Reliabilityy and operating margins of LWR fuels

    International Nuclear Information System (INIS)

    Strasser, A.A.; Lindquist, K.O.

    1977-01-01

    The margins to fuel thermal operating limits under normal and accident conditions are key to plant operating flexibility and impact on availability and capacity factor. Fuel performance problems that do not result in clad breach, can reduce these margins. However, most have or can be solved with design changes. Regulatory changes have been major factors in eroding these margins. Various methods for regaining the margins are discussed

  15. Silenced, Silence, Silent: Motherhood in the Margins

    Science.gov (United States)

    Carpenter, Lorelei; Austin, Helena

    2007-01-01

    This project explores the experiences of women who mother children with ADHD. The authors use the metaphor of the text and the margin. The text is the "motherhood myth" that describes a particular sort of "good" mothering. The margin is the space beyond that text. This marginal space is inhabited by some or all of the mothers they spoke with, some…

  16. 12 CFR 220.4 - Margin account.

    Science.gov (United States)

    2010-01-01

    ... Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM CREDIT BY... securities. The required margin on a net long or net short commitment in a when-issued security is the margin...) Interest charged on credit maintained in the margin account; (ii) Premiums on securities borrowed in...

  17. Geophysical constraints on geodynamical processes at convergent margins

    DEFF Research Database (Denmark)

    Artemieva, Irina; Thybo, Hans; Shulgin, Alexey

    2016-01-01

    Convergent margins, being the boundaries between colliding lithospheric plates, form the most disastrous areas in the world due to intensive, strong seismicity and volcanism. We review global geophysical data in order to illustrate the effects of the plate tectonic processes at convergent margins......, at least, one of the plates is oceanic. However, the oldest oceanic plate in the Pacific ocean has the smallest convergence rate. (2) The presence of an oceanic plate is, in general, required for generation of high-magnitude (M>8.0) earthquakes and for generating intermediate and deep seismicity along...... to shallow mantle levels....

  18. Nuclear reactors safety issues

    International Nuclear Information System (INIS)

    Barre, Francois; Seiler, Nathalie

    2008-01-01

    fuels as well as the applied methodologies. The IRSN proceeds in a relevant and independent assessment of the submitted safety reports. To achieve this goal and maintain over time an independent and relevant assessment capability, the IRSN relies on the excellence of its experts and on state of art techniques and knowledge. The IRSN contributes by its work in key area to cutting edge research and development in order to drive nuclear industry towards making the best use of scientific and technological progress for improving safety, environmental protection and health. To maintain at all times the state of the art knowledge and the operational expertise necessary to deal efficiently with major nuclear accident consequences, the IRSN carries out, on the one hand, its own research and development programs to gain accurate knowledge on still unknown phenomena for safety analysis. On the other hand, the IRSN works out its own scientific calculation methodologies involving industrial calculation chain. Concerning more particularly the 'two-phase flows' thematic, The ISRN must correctly simulate the primary fluid behavior in the reactor in normal operation as well as in accidental situations, to estimate if, in such situations, the core reactor state is fully safe and any safety risk is undergone The research and development programs launched at the ISRN on two-phase flows gather work on advanced thermohydraulic configurations encounter in various reactor states (normal operation or accidental situations), in particular: (i)The estimation of the margin to the critical heat flux in normal operation (DNBR), (ii) The pressurized thermal shock, which is due to mechanical important constraints in the reactor vessel resulting from the injection of a cold fluid in case of emergency cooling (PTS), (iii) The reactivity insertion accident (RIA), (iv) The loss of coolant accident (LOCA), (vi) The accidents in spent-fuel pools and (vii) The severe accident, which could lead to core

  19. Shutdown Safety in NEK

    International Nuclear Information System (INIS)

    Gluhak, Mario; Senegovic, Marko

    2014-01-01

    Industry performance analysis since 2004 has revealed that 23% of the events reported to WANO occurred during outage periods. Given the fact that a plant is in the outage only 5 percent of the time, this emphasizes the importance of shutdown safety and measures station staffs undertake to maintain effective barriers to safety margins during the outage. Back in 1990s, the industry adopted guidance to meet safety requirements by focusing on safety functions. Both WANO and INPO released various documents, reports and guidelines to help accomplish those requirements. However, in the last decade inadequate 'defence in depth' has led to several events affecting shutdown safety and challenging one of the most important nuclear safety principles: 'The special characteristics of nuclear technology are taken into account in all decisions and actions. Reactivity control, continuity of core cooling, and integrity of fission product barriers are valued as essential, distinguishing attributes of nuclear station work environment'. NEK has recognized the importance of 'defence in depth'Industry performance analysis since 2004 has revealed that 23% of the events reported to WANO occurred during outage periods. Given the fact that a plant is in the outage only 5 percent of the time, this emphasizes the importance of shutdown safety and measures station staffs undertake to maintain effective barriers to safety margins during the outage. Back in 1990s, the industry adopted guidance to meet safety requirements by focusing on safety functions. Both WANO and INPO released various documents, reports and guidelines to help accomplish those requirements. However, in the last decade inadequate 'defence in depth' has led to several events affecting shutdown safety and challenging one of the most important nuclear safety principles: 'The special characteristics of nuclear technology are taken into account in all decisions and actions. Reactivity

  20. Model-Based Systems Engineering Approach to Managing Mass Margin

    Science.gov (United States)

    Chung, Seung H.; Bayer, Todd J.; Cole, Bjorn; Cooke, Brian; Dekens, Frank; Delp, Christopher; Lam, Doris

    2012-01-01

    When designing a flight system from concept through implementation, one of the fundamental systems engineering tasks ismanaging the mass margin and a mass equipment list (MEL) of the flight system. While generating a MEL and computing a mass margin is conceptually a trivial task, maintaining consistent and correct MELs and mass margins can be challenging due to the current practices of maintaining duplicate information in various forms, such as diagrams and tables, and in various media, such as files and emails. We have overcome this challenge through a model-based systems engineering (MBSE) approach within which we allow only a single-source-of-truth. In this paper we describe the modeling patternsused to capture the single-source-of-truth and the views that have been developed for the Europa Habitability Mission (EHM) project, a mission concept study, at the Jet Propulsion Laboratory (JPL).

  1. On the marginally relevant operator in z=2 Lifshitz holography

    International Nuclear Information System (INIS)

    Holsheimer, Kristian

    2014-01-01

    We study holographic renormalization and RG flow in a strongly-coupled Lifshitz-type theory in 2+1 dimensions with dynamical exponent z=2. The bottom-up gravity dual we use is 3+1 dimensional Einstein gravity coupled to a massive vector field. This model contains a marginally relevant operator around the Lifshitz fixed point. We show how holographic renormalization works in the presence of this marginally relevant operator without the need to introduce explicitly cutoff-dependent counterterms. A simple closed-form expression is found for the renormalized on-shell action. We also discuss how asymptotically Lifshitz geometries flow to AdS in the interior due to the marginally relevant operator. We study the behavior of the renormalized entanglement entropy and confirm that it decreases monotonically along the Lifshitz-to-AdS RG flow

  2. What is the risk of death or severe harm due to bone cement implantation syndrome among patients undergoing hip hemiarthroplasty for fractured neck of femur? A patient safety surveillance study

    Science.gov (United States)

    Rutter, Paul D; Panesar, Sukhmeet S; Darzi, Ara; Donaldson, Liam J

    2014-01-01

    Objective To estimate the risk of death or severe harm due to bone cement implantation syndrome (BCIS) among patients undergoing hip hemiarthroplasty for fractured neck of femur. Setting Hospitals providing secondary and tertiary care throughout the National Health Service (NHS) in England and Wales. Participants Cases reported to the National Reporting and Learning System (NRLS) in which the reporter clearly describes severe acute patient deterioration associated with cement use in hip hemiarthroplasty for fractured neck of femur (assessed independently by two reviewers). Outcome measures Primary—number of reported deaths, cardiac arrests and periarrests per year. Secondary—timing of deterioration and outcome in relation to cement insertion. Results Between 2005 and 2012, the NRLS received 62 reports that clearly describe death or severe harm associated with the use of cement in hip hemiarthroplasty for fractured neck of femur. There was one such incident for every 2900 hemiarthroplasties for fractured neck of femur during the period. Of the 62 reports, 41 patients died, 14 were resuscitated from cardiac arrest and 7 from periarrest. Most reports (55/62, 89%) describe acute deterioration occurring during or within a few minutes of cement insertion. The vast majority of deaths (33/41, 80%) occurred on the operating table. Conclusions These reports provide narrative evidence from England and Wales that cement use in hip hemiarthroplasty for fractured neck of femur is associated with instances of perioperative death or severe harm consistent with BCIS. In 2009, the National Patient Safety Agency publicised this issue and encouraged the use of mitigation measures. Three-quarters of the deaths in this study have occurred since that alert, suggesting incomplete implementation or effectiveness of those mitigation measures. There is a need for stronger evidence that weighs the risks and benefits of cement in hip hemiarthroplasty for fractured neck of femur. PMID

  3. Analysis and study on core power capability with margin method

    International Nuclear Information System (INIS)

    Liu Tongxian; Wu Lei; Yu Yingrui; Zhou Jinman

    2015-01-01

    Core power capability analysis focuses on the power distribution control of reactor within the given mode of operation, for the purpose of defining the allowed normal operating space so that Condition Ⅰ maneuvering flexibility is maintained and Condition Ⅱ occurrences are adequately protected by the reactor protection system. For the traditional core power capability analysis methods, such as synthesis method or advanced three dimension method, usually calculate the key safety parameters of the power distribution, and then verify that these parameters meet the design criteria. For PWR with on-line power distribution monitoring system, core power capability analysis calculates the most power level which just meets the design criteria. On the base of 3D FAC method of Westinghouse, the calculation model of core power capability analysis with margin method is introduced to provide reference for engineers. The core power capability analysis of specific burnup of Sanmen NPP is performed with the margin method. The results demonstrate the rationality of the margin method. The calculation model of the margin method not only helps engineers to master the core power capability analysis for AP1000, but also provides reference for engineers for core power capability analysis of other PWR with on-line power distribution monitoring system. (authors)

  4. A randomised, double-masked, controlled study of the efficacy and safety of intravitreal bevacizumab versus ranibizumab in the treatment of macular oedema due to branch retinal vein occlusion: MARVEL Report No. 1.

    Science.gov (United States)

    Narayanan, Raja; Panchal, Bhavik; Das, Taraprasad; Chhablani, Jay; Jalali, Subhadra; Ali, M Hasnat

    2015-07-01

    To assess the efficacy and safety of intravitreal bevacizumab (IVB) compared with ranibizumab (IVR) in the treatment of macular oedema due to branch retinal vein occlusion (BRVO). In this prospective, randomised, non-inferiority trial, 75 participants with macular oedema due to BRVO received intravitreal injections of ranibizumab or bevacizumab after 1:1 block randomisation. The primary outcome measure was the difference in mean changes in best-corrected visual acuity (BCVA) at 6 months. Secondary outcome measures included mean change in central retinal thickness (CRT), the proportion of patients improving by >15 letters and the proportion of patients developing neovascularisation. Participants received either IVR (n=37) or IVB (n=38). The mean BCVA at baseline was 52.8±14.4 letters (20/80) and 56.1±10.0 letters (20/80) (p=0.24) in the ranibizumab and bevacizumab groups, respectively. At 6 months, the mean gains in BCVA were +18.1 letters (p<0.0001; 95% CI, +12.8 to +22.6) in the ranibizumab group and +15.6 letters (p<0.0001; 95% CI +12.0 to +20.5) in the bevacizumab group. The difference between the mean visual gains of the treated groups (bevacizumab-ranibizumab) was -2.5 letters (95% CI -8.0 to +5.0; p=0.74). Mean reductions in CRT at 6 months were 177.1±122.3 µm in the ranibizumab group (p<0.0001) and 201.7±166.2 µm in the bevacizumab group (p<0.0001), with no significant difference between the two groups (p=0.48). The mean numbers of ranibizumab and bevacizumab injections were 3.2±1.5 and 3.0±1.4, respectively (p=0.55). Two serious adverse events occurred in the ranibizumab group and one in the bevacizumab group but both were unrelated to intravitreal injections. This study demonstrated significant gain in visual acuity in eyes with BRVO treated with either bevacizumab or ranibizumab. Pro-re-nata strategy was effective in maintaining the visual gain. http://www.ctri.nic.in/ CTRI/2012/01/003120. Published by the BMJ Publishing Group Limited

  5. An approximate marginal logistic distribution for the analysis of longitudinal ordinal data

    NARCIS (Netherlands)

    Nooraee, Nazanin; Abegaz, Fentaw; Ormel, Johan; Wit, Ernst; van den Heuvel, Edwin R

    Subject-specific and marginal models have been developed for the analysis of longitudinal ordinal data. Subject-specific models often lack a population-average interpretation of the model parameters due to the conditional formulation of random intercepts and slopes. Marginal models frequently lack

  6. Overview of seismic margin insights gained from seismic PRA results

    International Nuclear Information System (INIS)

    Kennedy, R.P.; Sues, R.H.; Campbell, R.D.

    1986-01-01

    This paper presents the findings of a study conducted under NRC and EPRI sponsorship in which published seismic PRAs were reviewed in order to gain insight to the seismic margins inherent in existing nuclear plants. The approach taken was to examine the fragilities of those components which have been found to be dominant contributors to seismic risk at plants in low-to-moderate seismic regions (SSE levels between 0.12g and 0.25g). It is concluded that there is significant margin inherent in the capacity of most critical components above the plant design basis. For ground motions less than about 0.3g, the predominant sources of seismic risk are loss of offsite power coupled with random failure of the emergency diesels, non-recoverable circuit breaker trip due to relay chatter, unanchored equipment, unreinforced non-load bearing block walls, vertical water storage tanks, systems interactions and possibly soil liquefaction. Recommendations as to which components should be reviewed in seismic margin studies for margin earthquakes less than 0.3g, between 0.3g and 0.5g, and greater than 0.5g, developed by the NRC expert panel on the quantification of seismic margins (based on the review of past PRA data, earthquake experience data, and their own personal experience) are presented

  7. Aviation safety and maintenance under major organizational changes, investigating non-existing accidents.

    Science.gov (United States)

    Herrera, Ivonne A; Nordskag, Arve O; Myhre, Grete; Halvorsen, Kåre

    2009-11-01

    The objective of this paper is to discuss the following questions: Do concurrent organizational changes have a direct impact on aviation maintenance and safety, if so, how can this be measured? These questions were part of the investigation carried out by the Accident Investigation Board, Norway (AIBN). The AIBN investigated whether Norwegian aviation safety had been affected due to major organizational changes between 2000 and 2004. The main concern was the reduction in safety margins and its consequences. This paper presents a summary of the techniques used and explains how they were applied in three airlines and by two offshore helicopter operators. The paper also discusses the development of safety related indicators in the aviation industry. In addition, there is a summary of the lessons learned and safety recommendations. The Norwegian Ministry of Transport has required all players in the aviation industry to follow up the findings and recommendations of the AIBN study.

  8. Playground Safety

    Science.gov (United States)

    ... Prevention Fall Prevention Playground Safety Poisoning Prevention Road Traffic Safety Sports Safety Get Email Updates To receive ... at the Consumer Product Safety Commission’s Playground Safety website . References U.S. Consumer Product Safety Commission. Injuries and ...

  9. On elastic limit margins for earthquake design

    International Nuclear Information System (INIS)

    Buchhardt, F.; Matthees, W.; Magiera, G.

    1987-01-01

    In the Federal Republic of Germany KTA rule 2201 being the basis for the design of nuclear power plants against seismic events is now under discussion for revisions. One of the main demands to modify KTA rule 2201 consists in cancelling the existing design philosophy, i.e. design against an operating basis earthquake (AEB) as well as against a safe shutdown earthquake (SEB). When using the present rule the 'lower' earthquake (AEB) can become design-predominant, since for AEB and SEB different types of load cases are to be superimposed with different safety factors. The scope of this study is to quantify by parametric analyses so-called 'elastic bearing capacity limit margins' for seismic events; hereby different seismic input criteria - conventional as well as recently proposed are taken into account to investigate the influence of eventual modifications in seismic design philosophy. This way a relation between AEB and SEB has to be defined so that SEB is just still predominant for the design while AEB still will yield to elastic behaviour. The study covers all German site conditions

  10. Seismic margins and calibration of piping systems

    International Nuclear Information System (INIS)

    Shieh, L.C.; Tsai, N.C.; Yang, M.S.; Wong, W.L.

    1985-01-01

    The Seismic Safety Margins Research Program (SSMRP) is a US Nuclear Regulatory Commission-funded, multiyear program conducted by Lawrence Livermore National Laboratory (LLNL). Its objective is to develop a complete, fully coupled analysis procedure for estimating the risk of earthquake-induced radioactive release from a commercial nuclear power plant and to determine major contributors to the state-of-the-art seismic and systems analysis process and explicitly includes the uncertainties in such a process. The results will be used to improve seismic licensing requirements for nuclear power plants. In Phase I of SSMRP, the overall seismic risk assessment methodology was developed and assembled. The application of this methodology to the seismic PRA (Probabilistic Risk Assessment) at the Zion Nuclear Power Plant has been documented. This report documents the method deriving response factors. The response factors, which relate design calculated responses to best estimate values, were used in the seismic response determination of piping systems for a simplified seismic probablistic risk assessment. 13 references, 31 figures, 25 tables

  11. Nuclear Safety Review 2013

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-07-15

    The Nuclear Safety Review 2013 focuses on the dominant nuclear safety trends, issues and challenges in 2012. The Executive Overview provides crosscutting and worldwide nuclear safety information along with a summary of the major sections covered in this report. Sections A-E of this report cover improving radiation, transport and waste safety; strengthening safety in nuclear installations; improving regulatory infrastructure and effectiveness; enhancing emergency preparedness and response (EPR); and civil liability for nuclear damage. The Appendix provides details on the activities of the Commission on Safety Standards (CSS), and activities relevant to the IAEA Safety Standards. The world nuclear community has made noteworthy progress in strengthening nuclear safety in 2012, as promoted by the IAEA Action Plan on Nuclear Safety (hereinafter referred to as ''the Action Plan''). For example, an overwhelming majority of Member States with operating nuclear power plants (NPPs) have undertaken and essentially completed comprehensive safety reassessments ('stress tests') with the aim of evaluating the design and safety aspects of plant robustness to protect against extreme events, including: defence in depth, safety margins, cliff edge effects, multiple failures, and the prolonged loss of support systems. As a result, many have introduced additional safety measures including mitigation of station blackout. Moreover, the IAEA's peer review services and safety standards have been reviewed and strengthened where needed. Capacity building programmes have been built or improved, and EPR programmes have also been reviewed and improved. Furthermore, in 2012, the IAEA continued to share lessons learned from the Fukushima Daiichi accident with the nuclear community including through three international experts' meetings (IEMs) on reactor and spent fuel safety, communication in the event of a nuclear or radiological emergency, and protection against extreme earthquakes and tsunamis.

  12. Nuclear Safety Review 2013

    International Nuclear Information System (INIS)

    2013-07-01

    The Nuclear Safety Review 2013 focuses on the dominant nuclear safety trends, issues and challenges in 2012. The Executive Overview provides crosscutting and worldwide nuclear safety information along with a summary of the major sections covered in this report. Sections A-E of this report cover improving radiation, transport and waste safety; strengthening safety in nuclear installations; improving regulatory infrastructure and effectiveness; enhancing emergency preparedness and response (EPR); and civil liability for nuclear damage. The Appendix provides details on the activities of the Commission on Safety Standards (CSS), and activities relevant to the IAEA Safety Standards. The world nuclear community has made noteworthy progress in strengthening nuclear safety in 2012, as promoted by the IAEA Action Plan on Nuclear Safety (hereinafter referred to as ''the Action Plan''). For example, an overwhelming majority of Member States with operating nuclear power plants (NPPs) have undertaken and essentially completed comprehensive safety reassessments ('stress tests') with the aim of evaluating the design and safety aspects of plant robustness to protect against extreme events, including: defence in depth, safety margins, cliff edge effects, multiple failures, and the prolonged loss of support systems. As a result, many have introduced additional safety measures including mitigation of station blackout. Moreover, the IAEA's peer review services and safety standards have been reviewed and strengthened where needed. Capacity building programmes have been built or improved, and EPR programmes have also been reviewed and improved. Furthermore, in 2012, the IAEA continued to share lessons learned from the Fukushima Daiichi accident with the nuclear community including through three international experts' meetings (IEMs) on reactor and spent fuel safety, communication in the event of a nuclear or radiological emergency, and protection against extreme earthquakes and tsunamis

  13. Development of Safety Review Guide for the Periodic Safety Review of Reactor Vessel Internals

    International Nuclear Information System (INIS)

    Park, Jeongsoon; Ko, Hanok; Kim, Seonjae; Jhung, Myungjo

    2013-01-01

    Aging management of the reactor vessel internals (RVIs) is one of the important issues for long-term operation of nuclear power plants (NPPs). Safety review on the assessment and management of the RVI aging is conducted through the process of a periodic safety review (PSR). The regulatory body should check that reactor facilities sustain safety functions in light of degradation due to aging and that the operator of a nuclear power reactor establishes and implements management program to deal with degradation due to aging in order to guarantee the safety functions and the safety margin as a result of PSR. KINS(Korea Institute of Nuclear Safety) has utilized safety review guides (SRG) which provide guidance to KINS staffs in performing safety reviews in order to assure the quality and uniformity of staff safety reviews. The KINS SRGs for the continued operation of pressurized water reactors (PWRs) published in 2006 contain areas of review regarding aging management of RVIs in chapter 2 (III.2.15, Appendix 2.0.1). However unlike the SRGs for the continued operation, KINS has not officially published the SRGs for the PSR of PWRs, but published them as a form of the research report. In addition to that, the report provides almost same review procedures for aging assessment and management of RVIs with the ones provided in the SRGs for the continued operation, it cannot provide review guidance specific to PSRs. Therefore, a PSR safety review guide should be developed for RVIs in PWRs. In this study, a draft PSR safety review guide for reactor vessel internals in PWRs is developed and provided. In this paper, a draft PSR safety review guide for reactor vessel internals (PSR SRG-RVIs) in PWRs is introduced and main contents of the draft are provided. However, since the PSR safety review guides for areas other than RVIs in the pressurized water reactors (PWRs) are expected to be developed in the near future, the draft PSR SRG-RVIs should be revisited to be compatible with

  14. Determinants of banks’ net interest margins in Central and Eastern Europe

    Directory of Open Access Journals (Sweden)

    Tomislav Rizdak

    2013-03-01

    Full Text Available This research analyzes the main determinants of the net interest margin of banks operating in Central and Eastern European (CEE countries in the period from 1999 to 2010. The results reveal several main drivers of net interest margins in the CEE. Prior to 2008 the net interest margins declined primarily due to strong capital inflows and stable macroeconomic environment. In the crisis period, significant rise in government debt accompanied by the increase in macroeconomic risks and abating capital inflows were pushing margins up while other factors such as low credit demand, higher capitalization and significantly increased share of non-performing loans pressured banks’ margins down. The results also confirm the important contribution of higher efficiency to lowering banks’ margins.

  15. Qualification of class 1e equipment: regulation, technological margins and test experience

    International Nuclear Information System (INIS)

    Pasco, Y.; Le Meur, M.; Henry, J.Y.; Droger, J.P.; Morange, E.; Roubault, J.

    1986-10-01

    French regulation requires licensee to qualify electrical equipment important to safety for service in nuclear power plants to ensure that the equipment can perform its safety function under the set of plausible operating conditions. The French regulatory texts entitled Fundamental safety rules have classified safety related electrical equipment in three main categories: k1, k2, k3, according to their location and operating conditions. The definition of a design basis accident test profile must account for margins applied to thermal hydraulic code outputs. Specific safety margins was added to cover uncertainties in qualification test representativity. Up to now, accidental sequence studies have shown the validity of such a qualification test profile. On the other hand, the results from post accident simulation tests have shown that it is useful not only to validate post accident operating life but also to reveal failures initiated during previous tests [fr

  16. Operating plant safety analysis needs

    International Nuclear Information System (INIS)

    Young, M.Y.; Love, D.S.

    1992-01-01

    The primary objective for nuclear power station owners is to operate and manage their plants safely. However, there is also a need to provide economical electric power, which requires that the unit be operated as efficiently as possible, consistent with the safety requirements. The objectives cited above can be achieved through the identification and use of available margins inherent in the plant design. As a result of conservative licensing and analytical approaches taken in the past, many of these margins may be found in the safety analysis limits within which plants currently operate. Improvements in the accuracy of the safety analysis, and a more realistic treatment of plant initial and boundary conditions, can make this margin available for a variety of uses which enhance plant performance, help to reduce O and M costs, and may help to extend licensed operation. Opportunities for improvement exist in several areas in the accident analysis normally performed for Chapter 15 of the FSAR. For example, recent modifications to the ECCS rule, 10CFR50.46 and Appendix K, allow use of margins previously unavailable in the analysis of the Loss of Coolant Accident (LOCA). To take advantage of this regulatory change, new methods are being developed to analyze both the large and small break loss of coolant accident (LOCA). As this margin is used, enhancements in the analysis of other transients will become necessary. The paper discusses accident analysis methods, future development needs, and analysis margin utilization in specific accident scenarios

  17. Evaluation of Thermal Margin Analysis Models for SMART

    International Nuclear Information System (INIS)

    Seo, Kyong Won; Kwon, Hyuk; Hwang, Dae Hyun

    2011-01-01

    Thermal margin of SMART would be analyzed by three different methods. The first method is subchannel analysis by MATRA-S code and it would be a reference data for the other two methods. The second method is an on-line few channel analysis by FAST code that would be integrated into SCOPS/SCOMS. The last one is a single channel module analysis by safety analysis. Several thermal margin analysis models for SMART reactor core by subchannel analysis were setup and tested. We adopted a strategy of single stage analysis for thermal analysis of SMART reactor core. The model should represent characteristics of the SMART reactor core including hot channel. The model should be simple as possible to be evaluated within reasonable time and cost

  18. Controlling marginally detached divertor plasmas

    Science.gov (United States)

    Eldon, D.; Kolemen, E.; Barton, J. L.; Briesemeister, A. R.; Humphreys, D. A.; Leonard, A. W.; Maingi, R.; Makowski, M. A.; McLean, A. G.; Moser, A. L.; Stangeby, P. C.

    2017-06-01

    A new control system at DIII-D has stabilized the inter-ELM detached divertor plasma state for H-mode in close proximity to the threshold for reattachment, thus demonstrating the ability to maintain detachment with minimal gas puffing. When the same control system was instead ordered to hold the plasma at the threshold (here defined as T e  =  5 eV near the divertor target plate), the resulting T e profiles separated into two groups with one group consistent with marginal detachment, and the other with marginal attachment. The plasma dithers between the attached and detached states when the control system attempts to hold at the threshold. The control system is upgraded from the one described in Kolemen et al (2015 J. Nucl. Mater. 463 1186) and it handles ELMing plasmas by using real time D α measurements to remove during-ELM slices from real time T e measurements derived from divertor Thomson scattering. The difference between measured and requested inter-ELM T e is passed to a PID (proportional-integral-derivative) controller to determine gas puff commands. While some degree of detachment is essential for the health of ITER’s divertor, more deeply detached plasmas have greater radiative losses and, at the extreme, confinement degradation, making it desirable to limit detachment to the minimum level needed to protect the target plate (Kolemen et al 2015 J. Nucl. Mater. 463 1186). However, the observed bifurcation in plasma conditions at the outer strike point with the ion B   ×  \

  19. Methods and Effects of Safety Enhancement in Korean PSR

    International Nuclear Information System (INIS)

    Kim, Young Gab; Park, Jong Woon

    2009-01-01

    Periodic Safety Review (PSR) is a comprehensive study on a nuclear power plant safety, taking into account aspects such as operational history, ageing, safety analyses and advances in code and standards since the time of construction. In Korea, PSRs have been performed for 20 units and have been effectively used to obtain an overall view of actual plant safety to determine reasonable and practical modifications that should be made in order to obtain a higher level of safety approaching that of modern plants. Among many safety enhancements achieved from Korean PSRs, new safety analyses are the important methods to confirm plant safety by increasing safety margin for specific safety issues. Methods and effects of safety enhancements applied in Korean PSRs are reviewed in this paper in light of new safety analyses to obtain additional safety margins

  20. Marginal cost application in the power industry

    International Nuclear Information System (INIS)

    Twardy, L.; Rusak, H.

    1994-01-01

    Two kind of marginal costs, the short-run and the long-run, are defined. The former are applied in conditions when the load increase is not accompanied neither by the increase of the transmission capacity not the installed capacity while the latter assume new investments to expand the power system. The long-run marginal costs be used to forecast optimized development of the system. They contain two main components: the marginal costs of capacity and the marginal costs of energy. When the long-run marginal costs are calculated, each component is considered for particular voltage levels, seasons of the year, hours of the day - selected depending on the system reliability factor as well as on its load level. In the market economy countries the long-run marginal costs can be used for setting up the electric energy tariffs. (author). 7 refs, 11 figs

  1. An integrated software system for core design and safety analyses: Cascade-3D

    International Nuclear Information System (INIS)

    Wan De Velde, A.; Finnemann, H.; Hahn, T.; Merk, S.

    1999-01-01

    The new Siemens program system CASCADE-3D (Core Analysis and Safety Codes for Advanced Design Evaluation) links some of the most advanced code packages for in-core fuel management and accident analysis: SAV95, PANBOX/COBRA and RELAP5. Consequently by using CASCADE-3D the potential of modern fuel assemblies and in-core fuel management strategies can be much better utilized because safety margins which had been reduced due to conservative methods are now predicted more accurately. By this innovative code system the customers can now take full advantage of the recent progress in fuel assembly design and in-core fuel management. (authors)

  2. The integrated code system CASCADE-3D for advanced core design and safety analysis

    International Nuclear Information System (INIS)

    Neufert, A.; Van de Velde, A.

    1999-01-01

    The new program system CASCADE-3D (Core Analysis and Safety Codes for Advanced Design Evaluation) links some of Siemens advanced code packages for in-core fuel management and accident analysis: SAV95, PANBOX/COBRA and RELAP5. Consequently by using CASCADE-3D the potential of modern fuel assemblies and in-core fuel management strategies can be much better utilized because safety margins which had been reduced due to conservative methods are now predicted more accurately. By this innovative code system the customers can now take full advantage of the recent progress in fuel assembly design and in-core fuel management.(author)

  3. Holocene sea level fluctuations on western Indian continental margin: An update

    Digital Repository Service at National Institute of Oceanography (India)

    Hashimi, N.H.; Nigam, R.; Nair, R.R.; Rajagopalan, G.

    A new Holocene curve is generated for the western Indian continental margin. While constructing this curve careful selection of the dates were made by giving due considerations to the genetic characteristics of the dated material. This new curve...

  4. Burn-up Credit Criticality Safety Benchmark-Phase II-E. Impact of Isotopic Inventory Changes due to Control Rod Insertions on Reactivity and the End Effect in PWR UO2 Fuel Assemblies

    International Nuclear Information System (INIS)

    Neuber, Jens Christian; Tippl, Wolfgang; Hemptinne, Gwendoline de; Maes, Philippe; Ranta-aho, Anssu; Peneliau, Yannick; Jutier, Ludyvine; Tardy, Marcel; Reiche, Ingo; Kroeger, Helge; Nakata, Tetsuo; Armishaw, Malcom; Miller, Thomas M.

    2015-01-01

    The report describes the final results of the Phase II-E Burn-up Credit Criticality Benchmark conducted by the Expert Group on Burn-up Credit Criticality Safety. The objective of Phase II of the Burn-up Credit Criticality Safety programme is to study the impact of axial burn-up profiles of PWR UO 2 spent fuel assemblies on the reactivity of PWR UO 2 spent fuel assembly configurations. The objective of the Phase II-E benchmark was to study the impact of changes on the spent nuclear fuel isotopic composition due to control rod insertion during depletion on the reactivity and the end effect of spent fuel assemblies with realistic axial burn-up profiles for different control rod insertion depths ranging from 0 cm (no insertion) to full insertion (i.e. to the case that the fuel assemblies were exposed to control rod insertion over their full active length). For this purpose two axial burn-up profiles have been extracted from an AREVA-NP-GmbH-owned 17x17-(24+1) PWR UO 2 spent fuel assembly burn-up profile database. One profile has an average burn-up of 30 MWd/kg U, the other profile is related to an average burn-up of 50 MWd/kg U. Two profiles with different average burn-up values were selected because the shape of the burn-up profile is affected by the average burn-up and the end effect depends on the average burn-up of the fuel. The Phase II-E benchmark exercise complements the Phase II-C and Phase II-D benchmark exercises. In Phase II-D different irradiation histories were analysed using different control rod insertion histories during depletion as well as irradiation histories without control rod insertion. But in all the histories analysed a uniform distribution of the burn-up and hence a uniform distribution of the isotopic composition were assumed; and in all the histories including any usage of control rods full insertion of the control rods was assumed. In Phase II-C the impact of the asymmetry of axial burn-up profiles on the reactivity and the end effect of

  5. Seismic margin assessment of spanish nuclear power plants: a perspective from industry and regulators

    International Nuclear Information System (INIS)

    Garcia-Monge, Juan; Beltran, Francisco; Sanchez-Cabanero, Jose G.

    2001-01-01

    The worldwide experience with probabilistic safety analysis (PSA) of nuclear power plants shows that the risk derived from earthquakes can be a significant contributor to core damage frequency in some instances. As a consequence, no severe accident safety assessment can be considered complete without giving, due consideration to seismic risk. This fact has been recognized by some regulators. in particular, by the U.S. Nuclear Regulatory Commission (NRC), who has included seismic risk assessment in its severe accident policy. The NRC severe accident policy was adopted by the Spanish nuclear regulator. the Consejo de Seguridad Nuclear (CSN). As a result. all plants in Spain were asked to perform a seismic risk analysis according to Supplements No. 4 and 5 of Generic Letter 88-20 and NUREG-1407, which included the containment failure analysis. At present in Spain there arc nine operating reactors at seven sites: six Westinghouse-PWR, two GE-BWR and one Siemens/KW U-PWR. The vintages are very different: the oldest plant started commercial operation in 1968 and the most recent, in 1988. In this framework, the Spanish Owners Group (SOG) proposed to CSN in 1994 to carry out the seismic risk analysis of the plants using seismic margin methodologies. This kind of methods requires, as a starting point, the definition of a seismic margin earthquake (SNIE), also called review level earthquake (RLL). For this purpose, tile SOG sponsored a general Probabilistic Seismic Hazard Analysis (PSHA) for the seven Spanish sites. The results of this PSHA were used by the SOG to define tile RLE and the scope of the study for each plant (binning of plants). The proposal was submitted to the CSN for evaluation. The CSN evaluation was based on the NRC practical experience and was helped by the technical advise of US Lawrence Livermore National Laboratory. The review showed that the uncertainties on seismic hazard had not been fully captured and that it would have been justified to consider a

  6. Study on structural seismic margin and probabilistic seismic risk. Development of a structural capacity-seismic risk diagram

    International Nuclear Information System (INIS)

    Nakajima, Masato; Ohtori, Yasuki; Hirata, Kazuta

    2010-01-01

    Seismic margin is extremely important index and information when we evaluate and account seismic safety of critical structures, systems and components quantitatively. Therefore, it is required that electric power companies evaluate the seismic margin of each plant in back-check of nuclear power plants in Japan. The seismic margin of structures is usually defined as a structural capacity margin corresponding to design earthquake ground motion. However, there is little agreement as to the definition of the seismic margin and we have no knowledge about a relationship between the seismic margin and seismic risk (annual failure probability) which is obtained in PSA (Probabilistic Safety Assessment). The purpose of this report is to discuss a definition of structural seismic margin and to develop a diagram which can identify a relation between seismic margin and seismic risk. The main results of this paper are described as follows: (1) We develop seismic margin which is defined based on the fact that intensity of earthquake ground motion is more appropriate than the conventional definition (i.e., the response-based seismic margin) for the following reasons: -seismic margin based on earthquake ground motion is invariant where different typed structures are considered, -stakeholders can understand the seismic margin based on the earthquake ground motion better than the response-based one. (2) The developed seismic margin-risk diagram facilitates us to judge easily whether we need to perform detailed probabilistic risk analysis or only deterministic analysis, given that the reference risk level although information on the uncertainty parameter beta is not obtained. (3) We have performed numerical simulations based on the developed method for four sites in Japan. The structural capacity-risk diagram differs depending on each location because the diagram is greatly influenced by seismic hazard information for a target site. Furthermore, the required structural capacity

  7. Aspects of marginal expenditures in energy sector

    International Nuclear Information System (INIS)

    Stojchev, D.; Kynev, K.

    1994-01-01

    Technical and economical problems of marginal analysis methodology, its application procedure in energy sector and marginal expenditures determination are outlined. A comparative characteristics of the application is made for different periods of time. The differences in calculation of the marginal expenditures and prices are discussed. The operational costs, investments and inflation are analyzed. The mechanism of application of this approach in different planing horizon is outlined. The role of the change in the costs in time, the time unit, volume, the scope of application, etc. are determined. The areas of transition from one to other form of marginal expenditures are shown. 4 refs. (orig.)

  8. The marginal costs of greenhouse gas emissions

    International Nuclear Information System (INIS)

    Tol, R.S.J.

    1999-01-01

    Estimates of the marginal costs of greenhouse gas emissions are on important input to the decision how much society would want to spend on greenhouse gas emission reduction. Marginal cost estimates in the literature range between $5 and $25 per ton of carbon. Using similar assumptions, the FUND model finds marginal costs of $9--23/tC, depending on the discount rate. If the aggregation of impacts over countries accounts for inequalities in income distribution or for risk aversion, marginal costs would rise by about a factor of 3. Marginal costs per region are an order of magnitude smaller than global marginal costs. The ratios between the marginal costs of CO 2 and those of CH 4 and N 2 O are roughly equal to the global warming potentials of these gases. The uncertainty about the marginal costs is large and right-skewed. The expected value of the marginal costs lies about 35% above the best guess, the 95-percentile about 250%

  9. On the evaluation of marginal expected shortfall

    DEFF Research Database (Denmark)

    Caporin, Massimiliano; Santucci de Magistris, Paolo

    2012-01-01

    In the analysis of systemic risk, Marginal Expected Shortfall may be considered to evaluate the marginal impact of a single stock on the market Expected Shortfall. These quantities are generally computed using log-returns, in particular when there is also a focus on returns conditional distribution....... In this case, the market log-return is only approximately equal to the weighed sum of equities log-returns. We show that the approximation error is large during turbulent market phases, with a subsequent impact on Marginal Expected Shortfall. We then suggest how to improve the evaluation of Marginal Expected...

  10. Assessment of seismic margin calculation methods

    International Nuclear Information System (INIS)

    Kennedy, R.P.; Murray, R.C.; Ravindra, M.K.; Reed, J.W.; Stevenson, J.D.

    1989-03-01

    Seismic margin review of nuclear power plants requires that the High Confidence of Low Probability of Failure (HCLPF) capacity be calculated for certain components. The candidate methods for calculating the HCLPF capacity as recommended by the Expert Panel on Quantification of Seismic Margins are the Conservative Deterministic Failure Margin (CDFM) method and the Fragility Analysis (FA) method. The present study evaluated these two methods using some representative components in order to provide further guidance in conducting seismic margin reviews. It is concluded that either of the two methods could be used for calculating HCLPF capacities. 21 refs., 9 figs., 6 tabs

  11. Regional Marginal Abatement Cost Curves for NOx

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data underlying the figures included in the manuscript "Marginal abatement cost curve for NOx incorporating controls, renewable electricity, energy efficiency and...

  12. [Resection margins in conservative breast cancer surgery].

    Science.gov (United States)

    Medina Fernández, Francisco Javier; Ayllón Terán, María Dolores; Lombardo Galera, María Sagrario; Rioja Torres, Pilar; Bascuñana Estudillo, Guillermo; Rufián Peña, Sebastián

    2013-01-01

    Conservative breast cancer surgery is facing a new problem: the potential tumour involvement of resection margins. This eventuality has been closely and negatively associated with disease-free survival. Various factors may influence the likelihood of margins being affected, mostly related to the characteristics of the tumour, patient or surgical technique. In the last decade, many studies have attempted to find predictive factors for margin involvement. However, it is currently the new techniques used in the study of margins and tumour localisation that are significantly reducing reoperations in conservative breast cancer surgery. Copyright © 2012 AEC. Published by Elsevier Espana. All rights reserved.

  13. Cryogenics safety

    International Nuclear Information System (INIS)

    Reider, R.

    1977-01-01

    The safety hazards associated with handling cryogenic fluids are discussed in detail. These hazards include pressure buildup when a cryogenic fluid is heated and becomes a gas, potential damage to body tissues due to surface contact, toxic risk from breathing air altered by cryogenic fluids, dangers of air solidification, and hazards of combustible cryogens such as liquified oxygen, hydrogen, or natural gas or of combustible mixtures. Safe operating procedures and emergency planning are described

  14. Evaluation of reactor safety

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-04-15

    Although the operation of nuclear reactors has a remarkably good record of safety, the prevention of possible reactor accidents is one of the major factors that atomic planners have to contend with. At the same time, excessive caution may breed an attitude that hampers progress, either by resisting new development or by demanding unnecessarily elaborate and expensive precautions out of proportion to the actual hazards involved. The best course obviously is to determine the possible dangers and adopt adequate measures for their prevention, providing of course, for a reasonable margin of error in judging the hazards and the effectiveness of the measures. The greater the expert understanding and thoroughness with which this is done, the narrower need the margin be. This is the basic idea behind the evaluation of reactor safety

  15. Thermal margin comparison between DAM and simple model

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jeonghun; Yook, Daesik [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2017-01-15

    The nuclear industry in Korea, has considered using a detail analysis model (DAM), which described each rod, to get more thermal margin with the design a dry storage facility for nuclear spent fuel (NSF). A DAM is proposed and a thermal analysis to determine the cladding integrity is performed using test conditions with a homogenized NSF assembly analysis model(Simple model). The result show that according to USA safety criteria, temperature of canister surface has to keep below 500 K in normal condition and 630 K in excess condition. A commercial Computational Fluid Dynamics (CFD) called ANSYS Fluent version 14.5 was used.

  16. An assessment of seismic margins in nuclear plant piping

    International Nuclear Information System (INIS)

    Chen, W.P.; Jaquay, K.R.; Chokshi, N.C.; Terao, D.

    1995-01-01

    Interim results of an ongoing program to assist the U.S. Nuclear Regulatory Commission (NRC) in developing regulatory positions on the seismic analyses of piping and overall safety margins of piping systems are reported. Results of reviews of previous seismic testing, primarily the Electric Power Research Institute (EPRI)/NRC Piping and Fitting Dynamic Reliability Program, and assessments of the ASME Code, Section III, piping seismic design criteria as revised by the 1994 Addenda are reported. Major issues are identified herein only. Technical details are to be provided elsewhere. (author). 4 refs., 2 figs

  17. Marginal cost pricing of electricity

    International Nuclear Information System (INIS)

    Edsbaecker, G.

    1980-01-01

    The discipline is economics and the phenomenon is the power system. The purpose of this system is to produce, transmit and consume electricity in such a way that the sum of consumers and suppliers surplus in maximized. This is accomplished by the means of marginal cost pricing. The concepts of the power system and the relations prevailing between and among them are picked out, defined and analyzed in the frames of economic theory and operations research. Methods are developed aiming at efficient prices so that the short run function of the power system is managed in such a way that the sum of conumers and suppliers surplus is maximized within the framwork of this system, i.e. value of service of the power system is maximized. The task of developing such methods is accomplished subject to mixed production resources, transmission losses, periodic demand and also when there is lack of information concerning future and cost conditions. The main results are methods which take to account the conditions stated above. Methods not only allowing for traditional cost minimizing but also for maximation of value of service including a process of reaching optimum by gradual adaption when demand and cost curves are not known in advance. (author)

  18. Categorical marginal models: quite extensive package for the estimation of marginal models for categorical data

    OpenAIRE

    Wicher Bergsma; Andries van der Ark

    2015-01-01

    A package accompanying the book Marginal Models for Dependent, Clustered, and Longitudinal Categorical Data by Bergsma, Croon, & Hagenaars, 2009. It’s purpose is fitting and testing of marginal models.

  19. Sustainable food production in marginal lands—Case of GDLA member countries

    Directory of Open Access Journals (Sweden)

    Shabbir A. Shahid

    2013-06-01

    Full Text Available Sustainable food production in the changing climate and dwindling water resources in the Global Dry Land Alliance (GDLA member countries is a real challenge, especially when considering marginal lands in dryland systems. The definition of marginal land is very vague and defined from different perspectives (pragmatism about marginal lands. Dryland itself indicates "marginality" due to water stress. In general, the abandoned agriculture land where food production is not economical, and has low inherent productivity potential is considered marginal; however, a land may be marginal for agriculture but vital for grazing. In this paper attempts have been made to give review of literature (water stress, extent of marginal saline lands, marginality. Policy matters (development of soil, water and agriculture strategies that GDLA and member countries should consider for future sustainable food production in their countries, including but not limited to, assessment of land resources for agriculture potential, defining, mapping and characterizing marginal lands, and use of innovative technologies (conservation agriculture, climate smart agriculture, integrated soil reclamation program and capacity building for food production, are discussed. The international perception (FAO, UNEP, CGIAR on marginal lands is also described. An innovative approach of using national biocapacity and ecological footprint is used to assess marginality of GDLA member countries. Ecological overshoot (using 1.5 earth planets and biocapacity debtor and creditor countries are highlighted. Challenges and best management practices for food production in marginal lands are included. Other important issues, like leasing land abroad, GDLA strategic food reserves and best management practices, innovative ideas for food production are shared. Finally recommendations are drafted for actions by GDLA, its member countries and the partners.

  20. Significance of post-resection tissue shrinkage on surgical margins of oral squamous cell carcinoma.

    Science.gov (United States)

    El-Fol, Hossam Abdelkader; Noman, Samer Abduljabar; Beheiri, Mohamed Galal; Khalil, Abdalla M; Kamel, Mahmoud Mohamed

    2015-05-01

    Resecting oral squamous cell carcinoma (SCC) with an appropriate margin of uninvolved tissue is critical in preventing local recurrence and in making decisions regarding postoperative radiation therapy. This task can be difficult due to the discrepancy between margins measured intraoperatively and those measured microscopically by the pathologist after specimen processing. A total of 61 patients underwent resective surgery with curative intent for primary oral SCC were included in this study. All patients underwent resection of the tumor with a measured 1-cm margin. Specimens were then submitted for processing and reviewing, and histopathologic margins were measured. The closest histopathologic margin was compared with the in situ margin (1 cm) to determine the percentage discrepancy. The mean discrepancy between the in situ margins and the histopathological margins of all close and positive margins were 47.6% for the buccal mucosa (with a P value corresponding to 0.05 equaling 2.1), which is statistically significant, 4.8% for the floor of mouth, 9.5% for the mandibular alveolus, 4.8% for the retromolar trigon, and 33.3% for the tongue. There is a significant difference among resection margins based on tumor anatomical location. Margins shrinkage after resection and processing should be considered at the time of the initial resection. Tumors located in the buccal mucosa show significantly greater discrepancies than tumors at other sites. These findings suggest that it is critical to consider the oral site when outlining margins to ensure adequacy of resection. Buccal SCC is an aggressive disease, and should be considered as an aggressive subsite within the oral cavity, requiring a radical and aggressive resective approach. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  1. Margem de segurança do meloxicam em cães: efeitos deletérios nas células sangüíneas e trato gastrintestinal Margin of safety of meloxicam in dogs: deleterious effects on blood cells and gastrointestinal tract

    Directory of Open Access Journals (Sweden)

    Marilac Maria Arnaldo Alencar

    2003-06-01

    Full Text Available Este trabalho investigou a margem de segurança do inibidor COX-2, meloxicam, em cães, enfocando seus efeitos deletérios nas células sangüíneas e no trato gastrintestinal. Para tanto, após uma avaliação clínico-laboratorial, os cães foram distribuídos nos seguintes grupos: I (placebo; n= 3, II (piroxicam; 1,0mg kg-1; n= 5, III (meloxicam; 0,2mg kg-1; n= 5, IV (meloxicam;1,0mg kg-1; n= 5 e V (meloxicam; 2,0mg kg-1; n= 5. Os fármacos foram usados, por via oral, por 16 dias. No 17º dia, repetiu-se o hemograma completo e, então, procedeu-se a eutanásia seguida pela necrópsia. No grupo I, não houve alterações dignas de nota. No grupo II, todos os cães apresentaram episódios moderados de vômito e diarréia. O perfil celular sangüíneo não foi significativamente modificado. Em dois cães, houve redução no hematócrito e na hemoglobina. Na necropsia, observaram-se focos hemorrágicos e lesões gastriduodenais moderadas. A análise microscópica revelou a presença de gastrite e enterite ulcerativa. No grupo III, quatro cães (80% apresentaram vômito e diarréia, sem alteração no perfil celular sangüíneo. Na análise macroscópica, observaram-se lesões brandas na mucosa gástrica e focos hemorrágicos no duodeno em quatro cães. Na histopatologia, observaram-se lesões sugestivas de discreta gastroenterite. No grupo IV, os cinco cães tiveram vômito e diarréia sanguinolenta. Quatro deles (80% apresentaram anemia (p This study investigated the margin of safety of the COX-2e inhibitor, meloxicam on blood cells and gastrointestinal tract of dogs. After a clinical and laboratorial examination, the dogs were distributed in the following groups: I (placebo; n=3, II (piroxicam: 1.0mg kg-1; n=5, III (meloxicam: 0.2mg kg-1; n=5, IV (meloxican: 1.0mg kg-1; n=5 and V (meloxican: 2.0mg kg-1; n=5. The drugs were given orally for 16 days. On the 17th day the complete hemogram was repeated and the euthanasia and necropsy were then

  2. Testing for marginal linear effects in quantile regression

    KAUST Repository

    Wang, Huixia Judy

    2017-10-23

    The paper develops a new marginal testing procedure to detect significant predictors that are associated with the conditional quantiles of a scalar response. The idea is to fit the marginal quantile regression on each predictor one at a time, and then to base the test on the t-statistics that are associated with the most predictive predictors. A resampling method is devised to calibrate this test statistic, which has non-regular limiting behaviour due to the selection of the most predictive variables. Asymptotic validity of the procedure is established in a general quantile regression setting in which the marginal quantile regression models can be misspecified. Even though a fixed dimension is assumed to derive the asymptotic results, the test proposed is applicable and computationally feasible for large dimensional predictors. The method is more flexible than existing marginal screening test methods based on mean regression and has the added advantage of being robust against outliers in the response. The approach is illustrated by using an application to a human immunodeficiency virus drug resistance data set.

  3. Testing for marginal linear effects in quantile regression

    KAUST Repository

    Wang, Huixia Judy; McKeague, Ian W.; Qian, Min

    2017-01-01

    The paper develops a new marginal testing procedure to detect significant predictors that are associated with the conditional quantiles of a scalar response. The idea is to fit the marginal quantile regression on each predictor one at a time, and then to base the test on the t-statistics that are associated with the most predictive predictors. A resampling method is devised to calibrate this test statistic, which has non-regular limiting behaviour due to the selection of the most predictive variables. Asymptotic validity of the procedure is established in a general quantile regression setting in which the marginal quantile regression models can be misspecified. Even though a fixed dimension is assumed to derive the asymptotic results, the test proposed is applicable and computationally feasible for large dimensional predictors. The method is more flexible than existing marginal screening test methods based on mean regression and has the added advantage of being robust against outliers in the response. The approach is illustrated by using an application to a human immunodeficiency virus drug resistance data set.

  4. The homogeneous marginal utility of income assumption

    NARCIS (Netherlands)

    Demuynck, T.

    2015-01-01

    We develop a test to verify if every agent from a population of heterogeneous consumers has the same marginal utility of income function. This homogeneous marginal utility of income assumption is often (implicitly) used in applied demand studies because it has nice aggregation properties and

  5. Values and marginal preferences in international business

    NARCIS (Netherlands)

    Maseland, Robbert; van Hoorn, Andre

    2010-01-01

    In a recent paper in this journal, Maseland and van Hoorn argued that values surveys tend to conflate values and marginal preferences. This assertion has been challenged by Brewer and Venaik, who claim that the wording of most survey items does not suggest that these elicit marginal preferences.

  6. Exactly marginal deformations from exceptional generalised geometry

    Energy Technology Data Exchange (ETDEWEB)

    Ashmore, Anthony [Merton College, University of Oxford,Merton Street, Oxford, OX1 4JD (United Kingdom); Mathematical Institute, University of Oxford,Andrew Wiles Building, Woodstock Road, Oxford, OX2 6GG (United Kingdom); Gabella, Maxime [Institute for Advanced Study,Einstein Drive, Princeton, NJ 08540 (United States); Graña, Mariana [Institut de Physique Théorique, CEA/Saclay,91191 Gif-sur-Yvette (France); Petrini, Michela [Sorbonne Université, UPMC Paris 05, UMR 7589, LPTHE,75005 Paris (France); Waldram, Daniel [Department of Physics, Imperial College London,Prince Consort Road, London, SW7 2AZ (United Kingdom)

    2017-01-27

    We apply exceptional generalised geometry to the study of exactly marginal deformations of N=1 SCFTs that are dual to generic AdS{sub 5} flux backgrounds in type IIB or eleven-dimensional supergravity. In the gauge theory, marginal deformations are parametrised by the space of chiral primary operators of conformal dimension three, while exactly marginal deformations correspond to quotienting this space by the complexified global symmetry group. We show how the supergravity analysis gives a geometric interpretation of the gauge theory results. The marginal deformations arise from deformations of generalised structures that solve moment maps for the generalised diffeomorphism group and have the correct charge under the generalised Reeb vector, generating the R-symmetry. If this is the only symmetry of the background, all marginal deformations are exactly marginal. If the background possesses extra isometries, there are obstructions that come from fixed points of the moment maps. The exactly marginal deformations are then given by a further quotient by these extra isometries. Our analysis holds for any N=2 AdS{sub 5} flux background. Focussing on the particular case of type IIB Sasaki-Einstein backgrounds we recover the result that marginal deformations correspond to perturbing the solution by three-form flux at first order. In various explicit examples, we show that our expression for the three-form flux matches those in the literature and the obstruction conditions match the one-loop beta functions of the dual SCFT.

  7. Steep microbial boundstone-dominated plaform margins

    NARCIS (Netherlands)

    Kenter, J.A.M.; Harris, P.M.; Della Porta, G.P.

    2005-01-01

    Seaward progradation of several kilometers has been documented mostly for leeward margin low-angle carbonate slope systems with a dominant platform top sediment source. However, steep and high-relief margins fronting deep basins can also prograde and as such are somewhat perplexing. Characteristics

  8. Nuclear power: Siting and safety

    International Nuclear Information System (INIS)

    Openshaw, S.

    1986-01-01

    By 2030, half, or even two-thirds, of all electricity may be generated by nuclear power. Major reactor accidents are still expected to be rare occurrences, but nuclear safety is largely a matter of faith. Terrorist attacks, sabotage, and human error could cause a significant accident. Reactor siting can offer an additional, design-independent margin of safety. Remote geographical sites for new plants would minimize health risks, protect the industry from negative changes in public opinion concerning nuclear energy, and improve long-term public acceptance of nuclear power. U.K. siting practices usually do not consider the contribution to safety that could be obtained from remote sites. This book discusses the present trends of siting policies of nuclear power and their design-independent margin of safety

  9. Margin Requirements and Equity Option Returns

    DEFF Research Database (Denmark)

    Hitzemann, Steffen; Hofmann, Michael; Uhrig-Homburg, Marliese

    In equity option markets, traders face margin requirements both for the options themselves and for hedging-related positions in the underlying stock market. We show that these requirements carry a significant margin premium in the cross-section of equity option returns. The sign of the margin...... premium depends on demand pressure: If end-users are on the long side of the market, option returns decrease with margins, while they increase otherwise. Our results are statistically and economically significant and robust to different margin specifications and various control variables. We explain our...... findings by a model of funding-constrained derivatives dealers that require compensation for satisfying end-users’ option demand....

  10. Margin Requirements and Equity Option Returns

    DEFF Research Database (Denmark)

    Hitzemann, Steffen; Hofmann, Michael; Uhrig-Homburg, Marliese

    In equity option markets, traders face margin requirements both for the options themselves and for hedging-related positions in the underlying stock market. We show that these requirements carry a significant "margin premium" in the cross-section of equity option returns. The sign of the margin...... premium depends on demand pressure: If end-users are on the long side of the market, option returns decrease with margins, while they increase otherwise. Our results are statistically and economically significant and robust to different margin specifications and various control variables. We explain our...... findings by a model of funding-constrained derivatives dealers that require compensation for satisfying end-users’ option demand....

  11. MARGINS: Toward a novel science plan

    Science.gov (United States)

    Mutter, John C.

    A science plan to study continental margins has been in the works for the past 3 years, with almost 200 Earth scientists from a wide variety of disciplines gathering at meetings and workshops. Most geological hazards and resources are found at continental margins, yet our understanding of the processes that shape the margins is meager.In formulating this MARGINS research initiative, fundamental issues concerning our understanding of basic Earth-forming processes have arisen. It is clear that a business-as-usual approach will not solve the class of problems defined by the MARGINS program; the solutions demand approaches different from those used in the past. In many cases, a different class of experiment will be required, one that is well beyond the capability of individual principle investigators to undertake on their own. In most cases, broadly based interdisciplinary studies will be needed.

  12. Evaluation of thermal margin during BWR neutron flux oscillation

    International Nuclear Information System (INIS)

    Takeuchi, Yutaka; Takigawa, Yukio; Chuman, Kazuto; Ebata, Shigeo

    1992-01-01

    Fuel integrity is very important, from the view point of nuclear power plant safety. Recently, neutron flux oscillations were observed at several BWR plants. The present paper describes the evaluations of the thermal margin during BWR neutron flux oscillations, using a three-dimensional transient code. The thermal margin is evaluated as MCPR (minimum critical power ratio). The LaSalle-2 event was simulated and the MCPR during the event was evaluated. It was a core-wide oscillation, at which a large neutron flux oscillation amplitude was observed. The results indicate that the MCPR had a sufficient margin with regard to the design limit. A regional oscillation mode, which is different from a core-wide oscillation, was simulated and the MCPR response was compared with that for the LaSalle-2 event. The MCPR decrement is greater in the regional oscillation, than in the core wide -oscillation, because of the sensitivity difference in a flow-to-power gain. A study was carried out about regional oscillation detectability, from the MCPR response view point. Even in a hypothetically severe case, the regional oscillation is detectable by LPRM signals. (author)

  13. A quantitative evaluation of seismic margin of typical sodium piping

    International Nuclear Information System (INIS)

    Morishita, Masaki

    1999-05-01

    It is widely recognized that the current seismic design methods for piping involve a large amount of safety margin. From this viewpoint, a series of seismic analyses and evaluations with various design codes were made on typical LMFBR main sodium piping systems. Actual capability against seismic loads were also estimated on the piping systems. Margins contained in the current codes were quantified based on these results, and potential benefits and impacts to the piping seismic design were assessed on possible mitigation of the current code allowables. From the study, the following points were clarified; 1) A combination of inelastic time history analysis and true (without margin)strength capability allows several to twenty times as large seismic load compared with the allowable load with the current methods. 2) The new rule of the ASME is relatively compatible with the results of inelastic analysis evaluation. Hence, this new rule might be a goal for the mitigation of seismic design rule. 3) With this mitigation, seismic design accommodation such as equipping with a large number of seismic supports may become unnecessary. (author)

  14. Reactor safety research - results and perspectives

    International Nuclear Information System (INIS)

    Banaschik, M.

    1989-01-01

    The work performed so far is an essential contribution to the determination of the safety margins of nuclear facilities and their systems and to the further development of safety engineering. The further development of safety engineering involves a shift of emphasis in reactor safety research towards event sequences beyond the design basis. The aim of this shift in emphasis is the further development of the preventive level. This is based on the fact that the conservative design of the operating and safety systems involves and essential safety potential. The R and D work is intended to help develop accident management measures and to take the plant back into the safe state even after severe accidents. In this context, it is necessary to make full use of the safety margins of the plant and to include the operating systems for coping with accidents. As a result of the aims, the research work approaches operating and plant-specific processes. (orig./DG) [de

  15. Investigation of neutronic and safety parameters variation in 5 MW research reactor due to U{sub 3}O{sub 8}Al fuel conversion to ThO{sub 2} + U{sub 3}O{sub 8}Al

    Energy Technology Data Exchange (ETDEWEB)

    Gholamzadeh, Zohreh; Alipoor, Zahra; Mirvakili, Seyed Mohammad [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Reactor Research School; Feghhi, Seyed Amir Hossein [Shahid Beheshti Univ., Tehran (Iran, Islamic Republic of). Dept. of Radiation Application; Vahedi, M.; Bagheri, H. [Univ. of Science and Technology, Tehran (Iran, Islamic Republic of). Energy Dept.; Tenreiro, Claudio [Talca Univ. (Chile). Energy Dept.

    2017-05-15

    Thorium-based fuels could comprise several advantages and are being investigated as a potentially competitive option with uranium-based fuels for research or power reactors. The present study investigates computationally the application of two different thorium-based fuels in a research reactor. Void and temperature reactivity coefficients, safety factor, power peaking factor, neutron generation time, effective delayed neutron fraction and {sup 135}Xe worth parameter were investigated for the fuel conversions. The results showed both the investigated fuels would not significantly disturb neutronic and safety parameters of the modeled core in comparison with its routine fuel loading. However, 235-enriched thorium based fuel concluded in noticeably reduction of High Level Waste (HLW) but 233-enriched type could be taken in attention because of its longer fuel cycle (∝15 %) and integrated neutron flux (∝23 %).

  16. 93-106, 2015 93 Multilevel random effect and marginal models

    African Journals Online (AJOL)

    Multilevel random effect and marginal models for longitudinal data ... and random effect models that take the correlation among measurements of the same subject ... comparing the level of redness, pain and irritability ... clinical trial evaluating the safety profile of a new .... likelihood-based methods to compare models and.

  17. Genetic Divergence and signatures of natural election in marginal populations of a Keystone, long-lived conifer, Eastern White Pine (Pinus strobus) from Northern Ontario

    Science.gov (United States)

    Vikram E. Chhatre; Om P. Rajora

    2014-01-01

    Marginal populations are expected to provide the frontiers for adaptation, evolution and range shifts of plant species under the anticipated climate change conditions. Marginal populations are predicted to show genetic divergence from central populations due to their isolation, and divergent natural selection and genetic drift operating therein. Marginal populations...

  18. Safety design of Qinshan Nuclear Power Plant

    International Nuclear Information System (INIS)

    Ouyang Yu; Zhang Lian; Du Shenghua; Zhao Jiayu

    1984-01-01

    Safety issues have been greatly emphasized through the design of the Qinshan Nuclear Power Plant. Reasonable safety margine has been taken into account in the plant design parameters, the design incorporated various safeguard systems, such as engineering safety feature systems, safety protection systems and the features to resist natural catastrophes, e. g. earthquake, hurricanes, tide and so on. Preliminary safety analysis and environmental effect assessment have been done and anti-accident provisions and emergency policy were carefully considered. Qinshan Nuclear Power Plant safety related systems are designed in accordance with the common international standards established in the late 70's, as well as the existing engineering standard of China

  19. Effect of Margin Designs on the Marginal Adaptation of Zirconia Copings.

    Science.gov (United States)

    Habib, Syed Rashid; Al Ajmi, Mohammed Ginan; Al Dhafyan, Mohammed; Jomah, Abdulrehman; Abualsaud, Haytham; Almashali, Mazen

    2017-09-01

    The aim of this in vitro study was to investigate the effect of Shoulder versus Chamfer margin design on the marginal adaptation of zirconia (Zr) copings. 40 extracted molar teeth were mounted in resin and prepared for zirconia crowns with two margin preparation designs (20=Shoulder and 20=Chamfer). The copings were manufactured by Cercon® (DeguDent GmbH, Germany) using the CAD/CAM system for each tooth. They were tried on each tooth, cemented, thermocycled, re-embedded in resin and were subsequently cross sectioned centrally into two equal mesial and distal halves. They were examined under electron microscope at 200 X magnification and the measurements were recorded at 5 predetermined points in micrometers (µm). The o verall mean marginal gap for the two groups was found to be 206.98+42.78µm with Shoulder margin design (Marginal Gap=199.50+40.72µm) having better adaptation compared to Chamfer (Marginal Gap=214.46+44.85µm). The independent-samples t-test showed a statistically non-significant difference (p=.113) between the means of marginal gap for Shoulder and Chamfer margin designs and the measurements were recorded at 5 predetermined points for the two groups. The Chamfer margin design appeared to offer the same adaptation results as the Shoulder margin design.

  20. Marginal and happy? The need for uniqueness predicts the adjustment of marginal immigrants.

    Science.gov (United States)

    Debrosse, Régine; de la Sablonnière, Roxane; Rossignac-Milon, Maya

    2015-12-01

    Marginalization is often presented as the strategy associated with the worst adjustment for immigrants. This study identifies a critical variable that buffers marginal immigrants from the negative effects of marginalization on adjustment: The need for uniqueness. In three studies, we surveyed immigrants recruited on university campuses (n = 119, n = 116) and in the field (n = 61). Among marginal immigrants, a higher need for uniqueness predicted higher self-esteem (Study 1), affect (Study 2), and life satisfaction (Study 3), and marginally higher happiness (Study 2) and self-esteem (Study 3). No relationship between the need for uniqueness and adjustment was found among non-marginal immigrants. The adaptive value of the need for uniqueness for marginal immigrants is discussed. © 2015 The British Psychological Society.

  1. Nuclear safety in perspective

    DEFF Research Database (Denmark)

    Andersson, K.; Sjöberg, B.M.D.; Lauridsen, Kurt

    2003-01-01

    The aim of the NKS/SOS-1 project has been to enhance common understanding about requirements for nuclear safety by finding improved means of communicat-ing on the subject in society. The project, which has been built around a number of seminars, wassupported by limited research in three sub......-projects: Risk assessment Safety analysis Strategies for safety management The report describes an industry in change due to societal factors. The concepts of risk and safety, safety management and systems forregulatory oversight are de-scribed in the nuclear area and also, to widen the perspective, for other...

  2. Auto Safety

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Auto Safety KidsHealth / For Parents / Auto Safety What's in this ... by teaching some basic rules. Importance of Child Safety Seats Using a child safety seat (car seat) ...

  3. Evaluation of fission product worth margins in PWR spent nuclear fuel burnup credit calculations

    International Nuclear Information System (INIS)

    Blomquist, R.N.; Finck, P.J.; Jammes, C.; Stenberg, C.G.

    1999-01-01

    Current criticality safety calculations for the transportation of irradiated LWR fuel make the very conservative assumption that the fuel is fresh. This results in a very substantial overprediction of the actual k eff of the transportation casks; in certain cases, this decreases the amount of spent fuel which can be loaded in a cask, and increases the cost of transporting the spent fuel to the repository. Accounting for the change of reactivity due to fuel depletion is usually referred to as ''burnup credit.'' The US DOE is currently funding a program aimed at establishing an actinide only burnup credit methodology (in this case, the calculated reactivity takes into account the buildup or depletion of a limited number of actinides). This work is undergoing NRC review. While this methodology is being validated on a significant experimental basis, it implicitly relies on additional margins: in particular, the absorption of neutrons by certain actinides and by all fission products is not taken into account. This provides an important additional margin and helps guarantee that the methodology is conservative provided these neglected absorption are known with reasonable accuracy. This report establishes the accuracy of fission product absorption rate calculations: (1) the analysis of European fission product worth experiments demonstrates that fission product cross-sections available in the US provide very good predictions of fission product worth; (2) this is confirmed by a direct comparison of European and US cross section evaluations; (3) accuracy of Spent Nuclear Fuel (SNF) fission product content predictions is established in a recent ORNL report where several SNF isotopic assays are analyzed; and (4) these data are then combined to establish in a conservative manner the fraction of the predicted total fission product absorption which can be guaranteed based on available experimental data

  4. Adequacy of Current Equivalent Margins Analysis (EMA) Guidance, Data and Methodologies for 60+ Years of Operation

    International Nuclear Information System (INIS)

    Server, W.; Hardin, T.; Cipolla, R.; Hall, B.

    2015-01-01

    In order to assure the structural integrity of reactor pressure vessels (RPVs), the fracture toughness of the ferritic steels used to fabricate the RPV must be shown to be adequate during their entire operating life, including extended license life. The Charpy V-notch (CVN) impact test has been used in the nuclear industry since it uses a small test specimen that can be irradiated in surveillance programs and provides an indirect way of assessing the fracture toughness of RPV steels. The effects of embrittlement typically are characterized by changes to the average Charpy curves measured before and after irradiation: shift of the 30 ft-lb (41 J) index temperature, and decrease in the CVN upper shelf energy (USE). Requirements in the USA for the USE of RPV belt-line materials are codified in Title 10, Code of Federal Regulations, Part 50 (10 CFR 50), Appendix G. Before irradiation, USE in the transverse (T-L) orientation for base materials and crack extension in the welding direction for weld materials must be greater than or equal to 75 ft-lb (102 J), and it is not to become less than 50 ft-lb (68 J) due to radiation embrittlement throughout the license of the RPV. If the projected USE of any RPV belt-line steel falls below 50 ft-lb (68 J), the projected value must be demonstrated to provide a margin of safety against ductile fracture equivalent to that required by Appendix G of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section XI. The analytical evaluation method used is called an equivalent margin analysis (EMA). This paper reviews the current status of EMAs and recommends improvements and clarifications that can be made to meet the needs of extended license life to 80 years. Focus is placed on analytical methodology, material property needs and proper implementation. (authors)

  5. Spectrum estimation method based on marginal spectrum

    International Nuclear Information System (INIS)

    Cai Jianhua; Hu Weiwen; Wang Xianchun

    2011-01-01

    FFT method can not meet the basic requirements of power spectrum for non-stationary signal and short signal. A new spectrum estimation method based on marginal spectrum from Hilbert-Huang transform (HHT) was proposed. The procession of obtaining marginal spectrum in HHT method was given and the linear property of marginal spectrum was demonstrated. Compared with the FFT method, the physical meaning and the frequency resolution of marginal spectrum were further analyzed. Then the Hilbert spectrum estimation algorithm was discussed in detail, and the simulation results were given at last. The theory and simulation shows that under the condition of short data signal and non-stationary signal, the frequency resolution and estimation precision of HHT method is better than that of FFT method. (authors)

  6. Methylation patterns in marginal zone lymphoma.

    Science.gov (United States)

    Arribas, Alberto J; Bertoni, Francesco

    Promoter DNA methylation is a major regulator of gene expression and transcription. The identification of methylation changes is important for understanding disease pathogenesis, for identifying prognostic markers and can drive novel therapeutic approaches. In this review we summarize the current knowledge regarding DNA methylation in MALT lymphoma, splenic marginal zone lymphoma, nodal marginal zone lymphoma. Despite important differences in the study design for different publications and the existence of a sole large and genome-wide methylation study for splenic marginal zone lymphoma, it is clear that DNA methylation plays an important role in marginal zone lymphomas, in which it contributes to the inactivation of tumor suppressors but also to the expression of genes sustaining tumor cell survival and proliferation. Existing preclinical data provide the rationale to target the methylation machinery in these disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Pathology of nodal marginal zone lymphomas.

    Science.gov (United States)

    Pileri, Stefano; Ponzoni, Maurilio

    Nodal marginal zone B cell lymphomas (NMZLs) are a rare group of lymphoid disorders part of the spectrum of marginal zone B-cell lymphomas, which encompass splenic marginal one B-cell lymphoma (SMZL) and extra nodal marginal zone of B-cell lymphoma (EMZL), often of MALT-type. Two clinicopathological forms of NMZL are recognized: adult-type and pediatric-type, respectively. NMZLs show overlapping features with other types of MZ, but distinctive features as well. In this review, we will focus on the salient distinguishing features of NMZL mostly under morphological/immunophenotypical/molecular perspectives in views of the recent acquisitions and forthcoming updated 2016 WHO classification of lymphoid malignancies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Policy Implementation, Role Conflict and Marginalization

    African Journals Online (AJOL)

    Prince Acheampong

    governance, their role has been politically, administratively, and financially ... of marginalization of the Traditional Systems in terms of legal, financial and ..... the President as the Chief Executive Officer of the district is another controlling factor.

  9. Limitations of ''margin'' in qualification tests

    International Nuclear Information System (INIS)

    Clough, R.L.; Gillen, K.T.

    1984-01-01

    We have carried out investigations of polymer radiation degradation behaviors which have brought to light a number of reasons why this concept of margin can break down. First of all, we have found that dose-rate effects vary greatly in magnitude. Thus, based on high dose-rate testing, poor materials with large dose-rate effects may be selected over better materials with small effects. Also, in certain cases, material properties have been found to level out (as with PVC) or reverse trend (as with buna-n) at high doses, so that ''margin'' may be ineffective, misleading, or counterproductive. For Viton, the material properties were found to change in opposite directions at high and low dose rates, making ''margin'' inappropriate. The underlying problem with the concept of ''margin'' is that differences in aging conditions can lead to fundamental differences in degradation mechanisms

  10. Mental Depreciation and Marginal Decision Making

    Science.gov (United States)

    Heath; Fennema

    1996-11-01

    We propose that individuals practice "mental depreciation," that is, they implicitly spread the fixed costs of their expenses over time or use. Two studies explore how people spread fixed costs on durable goods. A third study shows that depreciation can lead to two distinct errors in marginal decisions: First, people sometimes invest too much effort to get their money's worth from an expense (e.g., they may use a product a lot to spread the fixed expense across more uses). Second, people sometimes invest too little effort to get their money's worth: When people add a portion of the fixed cost to the current costs, their perceived marginal (i.e., incremental) costs exceed their true marginal costs. In response, they may stop investing because their perceived costs surpass the marginal benefits they are receiving. The latter effect is supported by two field studies that explore real board plan decisions by university students.

  11. Introduction of the Amendment of IAEA Safety Requirements Reflected Lessons Learned from Fukushima Nuclear Accident

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sang-Kyu; Ahn, Hyung-Joon; Kim, Sun-Hae; Cheong, Jae-Hak [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    for the design basis for the installation and their associated uncertainties; consideration of hazards due to surface faulting and flooding; monitoring of hazards and periodic review of site specific hazards; strengthening the prevention of unacceptable radiological consequences to the public and the environment; preventing severe accident through strengthening the plant design basis, including strengthening the independence of level four of defense in- depth, consideration of external hazards and sufficient margins; periodic safety review; emergency preparedness; feedback of operating experience. The following examples of the IAEA requirements to mitigate the consequences of DECs are: role of the government and the regulatory body for emergency preparedness and response, strengthening severe accident mitigation measures; well defined and updated accident management program.

  12. Marketing margins and agricultural technology in Mozambique

    DEFF Research Database (Denmark)

    Arndt, Channing; Jensen, Henning Tarp; Robinson, Sherman

    2000-01-01

    of improved agricultural technology and lower marketing margins yield welfare gains across the economy. In addition, a combined scenario reveals significant synergy effects, as gains exceed the sum of gains from the individual scenarios. Relative welfare improvements are higher for poor rural households......Improvements in agricultural productivity and reductions in marketing costs in Mozambique are analysed using a computable general equilibrium (CGE) model. The model incorporates detailed marketing margins and separates household demand for marketed and home-produced goods. Individual simulations...

  13. In silico particle margination in blood flow

    OpenAIRE

    Müller, Kathrin

    2015-01-01

    A profound knowledge of margination, the migration of blood components to the vessel wall in blood flow, is required in order to understand the genesis of various diseases, as e.g., cardiovascular diseases or bleeding disorders. Margination of particles is a pre-condition for potential adhesion. Adhesion to the vessel wall is required for platelets, the protein von Willebrand factor (VWF), but also for drug and imaging agent carriers in order to perform their particular tasks. In the haemosta...

  14. Development of Audit Calculation Methodology for RIA Safety Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joosuk; Kim, Gwanyoung; Woo, Swengwoong [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-05-15

    The interim criteria contain more stringent limits than previous ones. For example, pellet-to-cladding mechanical interaction(PCMI) was introduced as a new failure criteria. And both short-term (e.g. fuel-to coolant interaction, rod burst) and long-term(e.g., fuel rod ballooning, flow blockage) phenomena should be addressed for core coolability assurance. For dose calculations, transient-induced fission gas release has to be accounted additionally. Traditionally, the approved RIA analysis methodologies for licensing application are developed based on conservative approach. But newly introduced safety criteria tend to reduce the margins to the criteria. Thereby, licensees are trying to improve the margins by utilizing a less conservative approach. In this situation, to cope with this trend, a new audit calculation methodology needs to be developed. In this paper, the new methodology, which is currently under developing in KINS, was introduced. For the development of audit calculation methodology of RIA safety analysis based on the realistic evaluation approach, preliminary calculation by utilizing the best estimate code has been done on the initial core of APR1400. Followings are main conclusions. - With the assumption of single full-strength control rod ejection in HZP condition, rod failure due to PCMI is not predicted. - And coolability can be assured in view of entalphy and fuel melting. - But, rod failure due to DNBR is expected, and there is possibility of fuel failure at the rated power conditions also.

  15. Professional Commitment and Professional Marginalism in Teachers

    Directory of Open Access Journals (Sweden)

    Kalashnikov A.I.

    2017-11-01

    Full Text Available The article reviews teachers' attitudes towards the teaching profession which can be expressed both in professional commitment and in professional marginalism. The dominance of professional marginalism could affect destructively the students as well as the teacher’s personality, hence the issues related to the content of personal position of a marginal and the rate of marginalism among teachers. It was suggested that marginalism could be revealed in the study of professional commitment. The study involved 81 teachers of Sverdlovsk secondary schools aged 21—60 years with work experience ranging from 1 month to 39 years. The Professional Commitment Questionnaire was used as the study technique. The results showed that negative emotional attitude towards the profession and reluctance to leave the profession were grouped as a separate factor. The dispersion factor was 12,5%. The factor loadings ranged from 0.42 to 0.84. The study proved that professional marginalism in teachers includes dissatisfaction with work, feelings of resentment against profession and an unwillingness to leave the profession.

  16. A quantitative analysis of transtensional margin width

    Science.gov (United States)

    Jeanniot, Ludovic; Buiter, Susanne J. H.

    2018-06-01

    Continental rifted margins show variations between a few hundred to almost a thousand kilometres in their conjugated widths from the relatively undisturbed continent to the oceanic crust. Analogue and numerical modelling results suggest that the conjugated width of rifted margins may have a relationship to their obliquity of divergence, with narrower margins occurring for higher obliquity. We here test this prediction by analysing the obliquity and rift width for 26 segments of transtensional conjugate rifted margins in the Atlantic and Indian Oceans. We use the plate reconstruction software GPlates (http://www.gplates.org) for different plate rotation models to estimate the direction and magnitude of rifting from the initial phases of continental rifting until breakup. Our rift width corresponds to the distance between the onshore maximum topography and the last identified continental crust. We find a weak positive correlation between the obliquity of rifting and rift width. Highly oblique margins are narrower than orthogonal margins, as expected from analogue and numerical models. We find no relationships between rift obliquities and rift duration nor the presence or absence of Large Igneous Provinces (LIPs).

  17. A symmetric safety valve

    International Nuclear Information System (INIS)

    Burtraw, Dallas; Palmer, Karen; Kahn, Danny

    2010-01-01

    How to set policy in the presence of uncertainty has been central in debates over climate policy. Concern about costs has motivated the proposal for a cap-and-trade program for carbon dioxide, with a 'safety valve' that would mitigate against spikes in the cost of emission reductions by introducing additional emission allowances into the market when marginal costs rise above the specified allowance price level. We find two significant problems, both stemming from the asymmetry of an instrument that mitigates only against a price increase. One is that most important examples of price volatility in cap-and-trade programs have occurred not when prices spiked, but instead when allowance prices collapsed. Second, a single-sided safety valve may have unintended consequences for investment. We illustrate that a symmetric safety valve provides environmental and welfare improvements relative to the conventional one-sided approach.

  18. Convergent tectonics and coastal upwelling: a history of the Peru continental margin ( Pacific).

    Science.gov (United States)

    von Huene, Roland E.; Suess, E.; Emeis, K.C.

    1987-01-01

    Late in 1986, scientists on the ODP drillship JOIDES Resolution confirmed that the upper slope of the Peruvian margin consists of continental crust whereas the lower slope comprises an accretionary complex. An intricate history of horizontal and vertical movements can be detected, and the locations of ancient centers of upwelling appear to have varied, partly due to tectonic movements of the margin. In this review of Leg 112, the 3 scientific leaders on this cruise discuss their results. -from Journal Editor

  19. Seismic margin reviews of nuclear power plants: Identification of important functions and systems

    International Nuclear Information System (INIS)

    Prassinos, P.G.; Moore, D.L.; Amico, P.J.

    1987-01-01

    The results from the review of the seven utility-sponsored seismic PRAs plus the Zion SSMRP have been used to develop some insights regarding the importance of various systems and functions to seismic margins. By taking this information and combining it with the fragility insights we can develop some functional/systemic screening guideline for margin studies. This screening approach will greatly reduce the scope of the analysis. It is possible only to come to conclusions regarding the importance of plant systems and safety functions for PWRs, for which six plants were studied. For PWRs, it is possible to categorize plant safety functions as belonging to one of two groups, one of which is important to the assessment of seismic margins and one of which is not. The important functional group involves only two functions that must be considered for estimating seismic margin. These two functions are shutting down the nuclear reaction and providing cooling to the reactor core in the time period immediately following the seismic event (that is, the injection phase or pre-residual heat removal time period). It is possible to reasonably estimate the seismic margin of the plant by performing a study only involving the analysis of the plant systems and structure which are required in order to perform the two functions. Such analysis must include an assessment of a complete set of seismic initiating events. (orig./HP)

  20. French Approach for Long Term Storage Safety

    International Nuclear Information System (INIS)

    Marciano, Jacob; Carreton, Jean-Pierre; Lizot, Marie Therese; Lhomme, Veronique

    2014-01-01

    IRSN presents its statement regarding long-term storage facilities; in France, the regulatory documents do not define the long term duration. The storage facility lifetime can only be appreciated according to the needs and materials stored therein. However, the magnitude of the long-term can be estimated at a few hundred years compared to a few decades for current storage. Usually, in France, construction of storage facilities is driven from the necessity various necessities, linked to the management of radioactive material (eg spent fuel) and to the management of radioactive waste. Because of the variety of 'stored materials and objects' (fission product solutions, plutonium oxide powders, activated solids, drums containing technological waste, spent fuel...), a great number of storage facility design solutions have been developed (surface, subsurface areas, dry or wet conditions...) in the World. After describing the main functions of a storage facility, IRSN displays the safety principles and the associated design principles. The specific design principles applied to particular storage (dry or wet spent fuel storage, depleted uranium or reprocessed uranium storage, plutonium storage, waste containing tritium storage, HLW and ILLW storage...) are also presented. Finally, the concerns due to the long-term duration storage and related safety assessment are developed. After discussing these issues, IRSN displays its statement. The authorization procedures governing the facility lifetime are similar to those of any basic nuclear installation, the continuation of the facility operation remaining subject to periodic safety reviews (in France, every 10 years). The applicant safety cases have to show, that the safety requirements are always met; this requires, at minimum, to take into account at the design stage, comfortable design margins. (author)

  1. High temperature reactor safety and environment

    International Nuclear Information System (INIS)

    Brisbois, J.; Charles, J.

    1975-01-01

    High-temperature reactors are endowed with favorable safety and environmental factors resulting from inherent design, main-component safety margins, and conventional safety systems. The combination of such characteristics, along with high yields, prove in addition, that such reactors are plagued with few problems, can be installed near users, and broaden the recourse to specific power, therefore fitting well within a natural environment [fr

  2. Margins for treatment planning of proton therapy

    International Nuclear Information System (INIS)

    Thomas, Simon J

    2006-01-01

    For protons and other charged particles, the effect of set-up errors on the position of isodoses is considerably less in the direction of the incident beam than it is laterally. Therefore, the margins required between the clinical target volume (CTV) and planning target volume (PTV) can be less in the direction of the incident beam than laterally. Margins have been calculated for a typical head plan and a typical prostate plan, for a single field, a parallel opposed and a four-field arrangement of protons, and compared with margins calculated for photons, assuming identical geometrical uncertainties for each modality. In the head plan, where internal motion was assumed negligible, the CTV-PTV margin reduced from approximately 10 mm to 3 mm in the axial direction for the single field and parallel opposed plans. For a prostate plan, where internal motion cannot be ignored, the corresponding reduction in margin was from 11 mm to 7 mm. The planning organ at risk (PRV) margin in the axial direction reduced from 6 mm to 2 mm for the head plan, and from 7 mm to 4 mm for the prostate plan. No reduction was seen on the other axes, or for any axis of the four-field plans. Owing to the shape of proton dose distributions, there are many clinical cases in which good dose distributions can be obtained with one or two fields. When this is done, it is possible to use smaller PTV and PRV margins. This has the potential to convert untreatable cases, in which the PTV and PRV overlap, into cases with a gap between PTV and PRV of adequate size for treatment planning

  3. Method for evaluation of risk due to seismic related design and construction errors based on past reactor experience

    International Nuclear Information System (INIS)

    Gonzalez Cuesta, M.; Okrent, D.

    1985-01-01

    This paper proposes a methodology for quantification of risk due to seismic related design and construction errors in nuclear power plants, based on information available on errors discovered in the past. For the purposes of this paper, an error is defined as any event that causes the seismic safety margins of a nuclear power plant to be smaller than implied by current regulatory requirements and industry common practice. Also, the actual reduction in the safety margins caused by the error will be called a deficiency. The method is based on a theoretical model of errors, called a deficiency logic diagram. First, an ultimate cause is present. This ultimate cause is consumated as a specific instance, called originating error. As originating errors may occur in actions to be applied a number of times, a deficiency generation system may be involved. Quality assurance activities will hopefully identify most of these deficiencies, requesting their disposition. However, the quality assurance program is not perfect and some operating plant deficiencies may persist, causing different levels of impact to the plant logic. The paper provides a way of extrapolating information about errors discovered in plants under construction in order to assess the risk due to errors that have not been discovered

  4. Accountable Accounting: Carbon-Based Management on Marginal Lands

    Directory of Open Access Journals (Sweden)

    Tara L. DiRocco

    2014-04-01

    Full Text Available Substantial discussion exists concerning the best land use options for mitigating greenhouse gas (GHG emissions on marginal land. Emissions-mitigating land use options include displacement of fossil fuels via biofuel production and afforestation. Comparing C recovery dynamics under these different options is crucial to assessing the efficacy of offset programs. In this paper, we focus on forest recovery on marginal land, and show that there is substantial inaccuracy and discrepancy in the literature concerning carbon accumulation. We find that uncertainty in carbon accumulation occurs in estimations of carbon stocks and models of carbon dynamics over time. We suggest that analyses to date have been largely unsuccessful at determining reliable trends in site recovery due to broad land use categories, a failure to consider the effect of current and post-restoration management, and problems with meta-analysis. Understanding of C recovery could be greatly improved with increased data collection on pre-restoration site quality, prior land use history, and management practices as well as increased methodological standardization. Finally, given the current and likely future uncertainty in C dynamics, we recommend carbon mitigation potential should not be the only environmental service driving land use decisions on marginal lands.

  5. Confinement margins for ignition and driven operation in Iter Eda ID

    International Nuclear Information System (INIS)

    Johner, J.

    1995-09-01

    Preliminary calculations for ITER EDA ID have been performed using the 1/2D thermal equilibrium code HELIOS. It is found that: - The maximum ignition margin for ITER ID (29%) is 6% less than for ITER OD (35%) and 5% less than for ITER CDA (34%). - Decreasing the ration τ * He /τ E from the nominal value 10 to a value of 5 gives a 12% gain in the maximum ignition margin. Increasing the ration from 10 to 15 causes a 22% loss in the margin. Furthermore, ignited equilibria non longer exist for τ * He /τ E ≥ 17.6. - Operation in driven mode with 50 MW of external power increases the confinement capability by 13%. With 100 MW, the improvement is 24%. - Lowering the fusion power from 1500 to 1000 MW slightly improves the maximum ignition margin (+5%) and allows operation below the Greenwald density limit. - A 10% reduction of the toroidal magnetic field with a correlative diminution of the plasma current for constant safety factor operation, causes a dramatic reduction (-18%) of the maximum ignition margin. - A fraction of neon of 0.68% would completely suppress the ignition margin. Furthermore, ignited equilibria, with the nominal fusion power and τ * He /τ E , no longer exist when the neon fraction exceeds 0.75%. (Author). 2 refs., 10 figs

  6. Reconstructing Rodinia by Fitting Neoproterozoic Continental Margins

    Science.gov (United States)

    Stewart, John H.

    2009-01-01

    Reconstructions of Phanerozoic tectonic plates can be closely constrained by lithologic correlations across conjugate margins by paleontologic information, by correlation of orogenic belts, by paleomagnetic location of continents, and by ocean floor magmatic stripes. In contrast, Proterozoic reconstructions are hindered by the lack of some of these tools or the lack of their precision. To overcome some of these difficulties, this report focuses on a different method of reconstruction, namely the use of the shape of continents to assemble the supercontinent of Rodinia, much like a jigsaw puzzle. Compared to the vast amount of information available for Phanerozoic systems, such a limited approach for Proterozoic rocks, may seem suspect. However, using the assembly of the southern continents (South America, Africa, India, Arabia, Antarctica, and Australia) as an example, a very tight fit of the continents is apparent and illustrates the power of the jigsaw puzzle method. This report focuses on Neoproterozoic rocks, which are shown on two new detailed geologic maps that constitute the backbone of the study. The report also describes the Neoproterozoic, but younger or older rocks are not discussed or not discussed in detail. The Neoproterozoic continents and continental margins are identified based on the distribution of continental-margin sedimentary and magmatic rocks that define the break-up margins of Rodinia. These Neoproterozoic continental exposures, as well as critical Neo- and Meso-Neoproterozoic tectonic features shown on the two new map compilations, are used to reconstruct the Mesoproterozoic supercontinent of Rodinia. This approach differs from the common approach of using fold belts to define structural features deemed important in the Rodinian reconstruction. Fold belts are difficult to date, and many are significantly younger than the time frame considered here (1,200 to 850 Ma). Identifying Neoproterozoic continental margins, which are primarily

  7. The operator's role and safety functions

    International Nuclear Information System (INIS)

    Corcoran, W.R.; Finnicum, D.J.; Hubbard, F.R.; Musick, C.R.; Walzer, R.F.

    1980-01-01

    A nuclear power plant can be thought of as a single system with two major subsystems: equipment and people. Both play important roles in nuclear safety. Whereas, in the past, the role of equipment had been emphasized in nuclear safety, the accident at Three Mile Island and its subsequent investigations point out the vital role of the operator. This paper outlines the operator's roles in nuclear safety and suggests how the concept of safety functions can be used to reduce economic losses and increase safety margins. (auth)

  8. Path to development of quantitative safety goals

    International Nuclear Information System (INIS)

    Joksimovic, V.; Houghton, W.J.

    1980-04-01

    There is a growing interest in defining numerical safety goals for nuclear power plants as exemplified by an ACRS recommendation. This paper proposes a lower frequency limit of approximately 10 -4 /reactor-year for design basis events. Below this frequency, down, to a small frequency such as 10 -5 /reactor-year, safety margin can be provided by, say, site emergency plans. Accident sequences below 10 -5 should not impact public safety, but it is prudent that safety research programs examine sequences with significant consequences. Once tentatively agreed upon, quantitative safety goals together with associated implementation tools would be factored into regulatory and design processes

  9. Nuclear safety

    International Nuclear Information System (INIS)

    1991-02-01

    This book reviews the accomplishments, operations, and problems faced by the defense Nuclear Facilities Safety Board. Specifically, it discusses the recommendations that the Safety Board made to improve safety and health conditions at the Department of Energy's defense nuclear facilities, problems the Safety Board has encountered in hiring technical staff, and management problems that could affect the Safety Board's independence and credibility

  10. Ferritin associates with marginal band microtubules

    International Nuclear Information System (INIS)

    Infante, Anthony A.; Infante, Dzintra; Chan, M.-C.; How, P.-C.; Kutschera, Waltraud; Linhartova, Irena; Muellner, Ernst W.; Wiche, Gerhard; Propst, Friedrich

    2007-01-01

    We characterized chicken erythrocyte and human platelet ferritin by biochemical studies and immunofluorescence. Erythrocyte ferritin was found to be a homopolymer of H-ferritin subunits, resistant to proteinase K digestion, heat stable, and contained iron. In mature chicken erythrocytes and human platelets, ferritin was localized at the marginal band, a ring-shaped peripheral microtubule bundle, and displayed properties of bona fide microtubule-associated proteins such as tau. Red blood cell ferritin association with the marginal band was confirmed by temperature-induced disassembly-reassembly of microtubules. During erythrocyte differentiation, ferritin co-localized with coalescing microtubules during marginal band formation. In addition, ferritin was found in the nuclei of mature erythrocytes, but was not detectable in those of bone marrow erythrocyte precursors. These results suggest that ferritin has a function in marginal band formation and possibly in protection of the marginal band from damaging effects of reactive oxygen species by sequestering iron in the mature erythrocyte. Moreover, our data suggest that ferritin and syncolin, a previously identified erythrocyte microtubule-associated protein, are identical. Nuclear ferritin might contribute to transcriptional silencing or, alternatively, constitute a ferritin reservoir

  11. Geomorphic response of a continental margin to tectonic and eustatic variations, the Levant margin during the Messinian Salinity Crisis

    Science.gov (United States)

    Ben Moshe, Liran; Ben-Avraham, Zvi; Enzel, Yehouda; Uri, Schattner

    2017-04-01

    During the Messinian Salinity Crisis (MSC, 5.97±0.01-5.33 Ma) the Mediterranean Levant margin experienced major eustatic and sedimentary cycles as well as tectonic motion along the nearby Dead Sea fault plate boundary. New structures formed along this margin with morphology responding to these changes. Our study focuses on changes in this morphology across the margin. It is based on interpretation of three 3D seismic reflection volumes from offshore Israel. Multi-attribute analysis aided the extraction of key reflectors. Morphologic analysis of these data quantified interacting eustasy, sedimentation, and tectonics. Late Messinian morphologic domains include: (a) continental shelf; (b) 'Delta' anticline, forming a ridge diagonal to the strike of the margin; (c) southward dipping 'Hadera' valley, separating between (a) and (b); (d) 'Delta Gap' - a water gap crossing perpendicular to the anticline axis, exhibiting a sinuous thalweg; (e) continental slope. Drainage across the margin developed in several stages. Remains of turbidite flows crossing the margin down-slope were spotted across the 'Delta' anticline. These flows accumulated with the MSC evaporate sequence and prior to the anticline folding. Rising of the anticline, above the then bathymetry, either blocked or diverted the turbidites. That rising also defined the Hadera valley. In-situ evaporates, covering the valley floor, are, in turn covered by a fan-delta at the distal end of the valley. The fan-delta complex contains eroded evaporites and Lago-Mare fauna. Its top is truncated by dendritic fluvial channels that drained towards the Delta Gap. The Delta Gap was carved through the Delta ridge in a morphological and structural transition zone. We propose that during the first stages of the MSC (5.97±0.01-5.59 ma) destabilization of the continental slope due to oscillating sea level produced gravity currents that flowed through the pre-existing Delta anticline. Subsequent folding of the Delta anticline

  12. Centrifugal Compressor Surge Margin Improved With Diffuser Hub Surface Air Injection

    Science.gov (United States)

    Skoch, Gary J.

    2002-01-01

    Aerodynamic stability is an important parameter in the design of compressors for aircraft gas turbine engines. Compression system instabilities can cause compressor surge, which may lead to the loss of an aircraft. As a result, engine designers include a margin of safety between the operating line of the engine and the stability limit line of the compressor. The margin of safety is typically referred to as "surge margin." Achieving the highest possible level of surge margin while meeting design point performance objectives is the goal of the compressor designer. However, performance goals often must be compromised in order to achieve adequate levels of surge margin. Techniques to improve surge margin will permit more aggressive compressor designs. Centrifugal compressor surge margin improvement was demonstrated at the NASA Glenn Research Center by injecting air into the vaned diffuser of a 4:1-pressure-ratio centrifugal compressor. Tests were performed using injector nozzles located on the diffuser hub surface of a vane-island diffuser in the vaneless region between the impeller trailing edge and the diffuser-vane leading edge. The nozzle flow path and discharge shape were designed to produce an air stream that remained tangent to the hub surface as it traveled into the diffuser passage. Injector nozzles were located near the leading edge of 23 of the 24 diffuser vanes. One passage did not contain an injector so that instrumentation located in that passage would be preserved. Several orientations of the injected stream relative to the diffuser vane leading edge were tested over a range of injected flow rates. Only steady flow (nonpulsed) air injection was tested. At 100 percent of the design speed, a 15-percent improvement in the baseline surge margin was achieved with a nozzle orientation that produced a jet that was bisected by the diffuser vane leading edge. Other orientations also improved the baseline surge margin. Tests were conducted at speeds below the

  13. The drone as an additional risk factor due to conditions not provided for in radiological safety at major events; O drone como fator adicional de risco decorrente de condicoes nao previstas na seguranca radiologica em grandes eventos

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Gilberto de Jesus

    2015-07-01

    Major international events are potential targets of terrorist actions, seeking instant publicity that events of this magnitude provide, with the intention of causing terror and disseminate its power to a large number of people worldwide. In this context, the critical analysis of additional risk factor linked to procedures and protocols adopted on radiation safety is important. The possibility of unforeseen situations of risk, especially those resulting from the current global technological development, is a fact. Radioactive material can be used in this type of terrorism in a wide range of devices and illicit trafficking of this material is a reality that worries the International Atomic Energy Agency. In the current technological development scenario of the world, the potential occurrence of terrorist acts using drones combined with radioactive material dispersal devices, is real. The recent history of drones incidents presents cases where, despite not having been necessarily terrorist motivation, their circumstances and characteristics favor the occurrence of malicious acts. This paper proposes to alert the need of updating the current security protocols, considering the potential association of this technology with radioactive dispersal devices. (author)

  14. Carfilzomib With or Without Rituximab in the Treatment of Waldenstrom Macroglobulinemia or Marginal Zone Lymphoma

    Science.gov (United States)

    2018-02-05

    Marginal Zone Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Waldenstrom Macroglobulinemia; Refractory Marginal Zone Lymphoma; Refractory Waldenstrom Macroglobulinemia; Waldenstrom Macroglobulinemia

  15. Fission product margin in burnup credit analyses

    International Nuclear Information System (INIS)

    Finck, P.J.; Stenberg, C.G.

    1998-01-01

    The US Department of Energy (DOE) is currently working toward the licensing of a methodology for using actinide-only burnup credit for the transportation of spent nuclear fuel (SNF). Important margins are built into this methodology. By using comparisons with a representative experimental database to determine bias factors, the methodology ensures that actinide concentrations and worths are estimated conservatively; furthermore, the negative net reactivity of certain actinides and all fission products (FPs) is not taken into account, thus providing additional margin. A future step of DOE's effort might aim at establishing an actinide and FP burnup credit methodology. The objective of this work is to establish the uncertainty to be applied to the total FP worth in SNF. This will serve two ends. First, it will support the current actinide-only methodology by demonstrating the margin available from FPs. Second, it will identify the major contributions to the uncertainty and help set priorities for future work

  16. Digital Margins : How spatially and socially marginalized communities deal with digital exclusion

    NARCIS (Netherlands)

    Salemink, Koen

    2016-01-01

    The increasing importance of the Internet as a means of communication has transformed economies and societies. For spatially and socially marginalized communities, this transformation has resulted in digital exclusion and further marginalization. This book presents a study of two kinds of

  17. Quantification of margins and uncertainties: Alternative representations of epistemic uncertainty

    International Nuclear Information System (INIS)

    Helton, Jon C.; Johnson, Jay D.

    2011-01-01

    In 2001, the National Nuclear Security Administration of the U.S. Department of Energy in conjunction with the national security laboratories (i.e., Los Alamos National Laboratory, Lawrence Livermore National Laboratory and Sandia National Laboratories) initiated development of a process designated Quantification of Margins and Uncertainties (QMU) for the use of risk assessment methodologies in the certification of the reliability and safety of the nation's nuclear weapons stockpile. A previous presentation, 'Quantification of Margins and Uncertainties: Conceptual and Computational Basis,' describes the basic ideas that underlie QMU and illustrates these ideas with two notional examples that employ probability for the representation of aleatory and epistemic uncertainty. The current presentation introduces and illustrates the use of interval analysis, possibility theory and evidence theory as alternatives to the use of probability theory for the representation of epistemic uncertainty in QMU-type analyses. The following topics are considered: the mathematical structure of alternative representations of uncertainty, alternative representations of epistemic uncertainty in QMU analyses involving only epistemic uncertainty, and alternative representations of epistemic uncertainty in QMU analyses involving a separation of aleatory and epistemic uncertainty. Analyses involving interval analysis, possibility theory and evidence theory are illustrated with the same two notional examples used in the presentation indicated above to illustrate the use of probability to represent aleatory and epistemic uncertainty in QMU analyses.

  18. Seismic analysis response factors and design margins of piping systems

    International Nuclear Information System (INIS)

    Shieh, L.C.; Tsai, N.C.; Yang, M.S.; Wong, W.L.

    1985-01-01

    The objective of the simplified methods project of the Seismic Safety Margins Research Program is to develop a simplified seismic risk methodology for general use. The goal is to reduce seismic PRA costs to roughly 60 man-months over a 6 to 8 month period, without compromising the quality of the product. To achieve the goal, it is necessary to simplify the calculational procedure of the seismic response. The response factor approach serves this purpose. The response factor relates the median level response to the design data. Through a literature survey, we identified the various seismic analysis methods adopted in the U.S. nuclear industry for the piping system. A series of seismic response calculations was performed. The response factors and their variabilities for each method of analysis were computed. A sensitivity study of the effect of piping damping, in-structure response spectra envelop method, and analysis method was conducted. In addition, design margins, which relate the best-estimate response to the design data, are also presented

  19. Drug Safety

    Science.gov (United States)

    ... over-the-counter drug. The FDA evaluates the safety of a drug by looking at Side effects ... clinical trials The FDA also monitors a drug's safety after approval. For you, drug safety means buying ...

  20. Nuclear safety

    International Nuclear Information System (INIS)

    Tarride, Bruno

    2015-10-01

    The author proposes an overview of methods and concepts used in the nuclear industry, at the design level as well as at the exploitation level, to ensure an acceptable safety level, notably in the case of nuclear reactors. He first addresses the general objectives of nuclear safety and the notion of acceptable risk: definition and organisation of nuclear safety (relationships between safety authorities and operators), notion of acceptable risk, deterministic safety approach and main safety principles (safety functions and confinement barriers, concept of defence in depth). Then, the author addresses the safety approach at the design level: studies of operational situations, studies of internal and external aggressions, safety report, design principles for important-for-safety systems (failure criterion, redundancy, failure prevention, safety classification). The next part addresses safety during exploitation and general exploitation rules: definition of the operation domain and of its limits, periodic controls and tests, management in case of incidents, accidents or aggressions

  1. Functional safety measurement in the automotive domain : adaptation of PSM

    NARCIS (Netherlands)

    Luo, Y.; Stelma, J.; Brand, van den M.G.J.

    2015-01-01

    In the safety domain, safety standards are used as a development guideline to keep the risk at an acceptable level. Safety of the safety-critical systems can be assessed according to those safety standards. This assessment process is called safety assurance. Due to the manual work, the safety

  2. Safety culture

    International Nuclear Information System (INIS)

    Keen, L.J.

    2003-01-01

    Safety culture has become a topic of increasing interest for industry and regulators as issues are raised on safety problems around the world. The keys to safety culture are organizational effectiveness, effective communications, organizational learning, and a culture that encourages the identification and resolution of safety issues. The necessity of a strong safety culture places an onus on all of us to continually question whether the safety measures already in place are sufficient, and are being applied. (author)

  3. Study on seismic design margin based upon inelastic shaking test of the piping and support system

    International Nuclear Information System (INIS)

    Ishiguro, Takami; Eto, Kazutoshi; Ikeda, Kazutoyo; Yoshii, Toshiaki; Kondo, Masami; Tai, Koichi

    2009-01-01

    In Japan, according to the revised Regulatory Guide for Aseismic Design of Nuclear Power Reactor Facilities, September 2006, criteria of design basis earthquakes of Nuclear Power Reactor Facilities become more severe. Then, evaluating seismic design margin took on a great importance and it has been profoundly discussed. Since seismic safety is one of the major key issues of nuclear power plant safety, it has been demonstrated that nuclear piping system possesses large safety margins by various durability test reports for piping in ultimate conditions. Though the knowledge of safety margin has been accumulated from these reports, there still remain some technical uncertainties about the phenomenon when both piping and support structures show inelastic behavior in extremely high seismic excitation level. In order to obtain the influences of inelastic behavior of the support structures to the whole piping system response when both piping and support structures show inelastic behavior, we examined seismic proving tests and we conducted simulation analyses for the piping system which focused on the inelastic behavior of the support to the whole piping system response. This paper introduces major results of the seismic shaking tests of the piping and support system and the simulation analyses of these tests. (author)

  4. Deregulated model and locational marginal pricing

    International Nuclear Information System (INIS)

    Sood, Yog Raj; Padhy, N.P.; Gupta, H.O.

    2007-01-01

    This paper presents a generalized optimal model that dispatches the pool in combination with privately negotiated bilateral and multilateral contracts while maximizing social benefit has been proposed. This model determines the locational marginal pricing (LMP) based on marginal cost theory. It also determines the size of non-firm transactions as well as pool demand and generations. Both firms as well as non-firm transactions are considered in this model. The proposed model has been applied to IEEE-30 bus test system. In this test system different types of transactions are added for analysis of the proposed model. (author)

  5. Slope failure of chalk channel margins

    DEFF Research Database (Denmark)

    Gale, A.; Anderskouv, Kresten; Surlyk, Finn

    2015-01-01

    provide evidence for recurring margin collapse of a long-lived Campanian channel. Compressionally deformed and thrust chalk hardgrounds are correlated to thicker, non-cemented chalk beds that form a broad, gentle anticline. These chalks represent a slump complex with a roll-over anticline of expanded, non......-cemented chalk in the head region and a culmination of condensed hardgrounds in the toe region. Observations strongly suggest that the slumping represents collapse of a channel margin. Farther northwards, the contemporaneous succession shows evidence of small-scale penecontemporaneous normal faulting towards...

  6. On probabilistically defined margins in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Papiez, Lech; Langer, Mark [Department of Radiation Oncology, Indiana University, Indianapolis, IN (United States)

    2006-08-21

    Margins about a target volume subject to external beam radiation therapy are designed to assure that the target volume of tissue to be sterilized by treatment is adequately covered by a lethal dose. Thus, margins are meant to guarantee that all potential variation in tumour position relative to beams allows the tumour to stay within the margin. Variation in tumour position can be broken into two types of dislocations, reducible and irreducible. Reducible variations in tumour position are those that can be accommodated with the use of modern image-guided techniques that derive parameters for compensating motions of patient bodies and/or motions of beams relative to patient bodies. Irreducible variations in tumour position are those random dislocations of a target that are related to errors intrinsic in the design and performance limitations of the software and hardware, as well as limitations of human perception and decision making. Thus, margins in the era of image-guided treatments will need to accommodate only random errors residual in patient setup accuracy (after image-guided setup corrections) and in the accuracy of systems designed to track moving and deforming tissues of the targeted regions of the patient's body. Therefore, construction of these margins will have to be based on purely statistical data. The characteristics of these data have to be determined through the central limit theorem and Gaussian properties of limiting error distributions. In this paper, we show how statistically determined margins are to be designed in the general case of correlated distributions of position errors in three-dimensional space. In particular, we show how the minimal margins for a given level of statistical confidence are found. Then, how they are to be used to determine geometrically minimal PTV that provides coverage of GTV at the assumed level of statistical confidence. Our results generalize earlier recommendations for statistical, central limit theorem

  7. On probabilistically defined margins in radiation therapy

    International Nuclear Information System (INIS)

    Papiez, Lech; Langer, Mark

    2006-01-01

    Margins about a target volume subject to external beam radiation therapy are designed to assure that the target volume of tissue to be sterilized by treatment is adequately covered by a lethal dose. Thus, margins are meant to guarantee that all potential variation in tumour position relative to beams allows the tumour to stay within the margin. Variation in tumour position can be broken into two types of dislocations, reducible and irreducible. Reducible variations in tumour position are those that can be accommodated with the use of modern image-guided techniques that derive parameters for compensating motions of patient bodies and/or motions of beams relative to patient bodies. Irreducible variations in tumour position are those random dislocations of a target that are related to errors intrinsic in the design and performance limitations of the software and hardware, as well as limitations of human perception and decision making. Thus, margins in the era of image-guided treatments will need to accommodate only random errors residual in patient setup accuracy (after image-guided setup corrections) and in the accuracy of systems designed to track moving and deforming tissues of the targeted regions of the patient's body. Therefore, construction of these margins will have to be based on purely statistical data. The characteristics of these data have to be determined through the central limit theorem and Gaussian properties of limiting error distributions. In this paper, we show how statistically determined margins are to be designed in the general case of correlated distributions of position errors in three-dimensional space. In particular, we show how the minimal margins for a given level of statistical confidence are found. Then, how they are to be used to determine geometrically minimal PTV that provides coverage of GTV at the assumed level of statistical confidence. Our results generalize earlier recommendations for statistical, central limit theorem

  8. The efficacy and safety of oral Tamsulosin controlled absorption system (OCAS for the treatment of lower urinary tract symptoms due to bladder outlet obstruction associated with benign prostatic hyperplasia: an open-label preliminary study

    Directory of Open Access Journals (Sweden)

    Bannakij Lojanapiwat

    2011-08-01

    Full Text Available AIMS: Tamsulosin, a superselective subtype alpha 1a and 1d blocker, is used for the treatment of male lower urinary tract symptoms (LUTS commonly caused by benign prostatic hyperplasia (BPH. This prospective study evaluated the efficacy and safety of a new formulation, Tamsulosin OCAS® (Oral Controlled Absorption System, for LUTS associated with BPH in Thai patients. MATERIALS AND METHODS: Fifty one patients over 40 years old with complaints of LUTS associated with BPH were recruited. Patients received an 8 week course of once daily 0.4 mg tamsulosin OCAS®, and were followed up at 2 (visit 3, 4 (visit 4 and 8 (visit 5 weeks post-treatment. At each visit, patients were assessed using the International Prostate Symptom Score (IPSS, Nocturia Quality of Life (N-QoL Questionnaire, QoL Assessment Index (IPSS-QoL, and International Index of Erectile Function (IIEF. The primary outcome was efficacy of Tamsulosin. The secondary outcomes included change in the mean number of nocturia episodes, hours of undisturbed sleep (HUS and uroflowmetry measurements. RESULTS: Total IPSS significantly decreased at week 8 from baseline (from 19.52 to 6.08; p < 0.001. Similarly, the voiding and storage subscores of IPSS also continued to improve significantly starting from the second and third visits, respectively (p < 0.001 versus baseline. The IPSS-QoL and N-QoL scores significantly improved at visit 3 through end of study. In addition, we observed significant nocturia and HUS improvement in their last clinic visit. Uroflowmetry parameters, Qmax and Qave, improved significantly at 3rd clinic visit . Three patients experienced mild dizziness. CONCLUSION: Tamsulosin OCAS® treatment led to significant improvements in LUTS, HUS and QoL in Thai patients with bladder outlet obstruction from BPH with few side effects.

  9. Various types of reported seismic margins and their uses

    International Nuclear Information System (INIS)

    Kennedy, R.P.

    1985-01-01

    Nuclear power plant structures and safety-related systems have been generally designed conservatively for a safe shutdown earthquake (SSE) and more conservatively for a smaller operating basis earthquake (OBE). Depending upon the relative conservatism of the design criteria, either the SSE or the OBE will control the design. In recent years, increasing knowledge in the geoscience field has led to a better understanding that, although highly unlikely, it is possible for the nuclear power plant to be subjected to earthquake ground motion greater than the ground motion for which the plant was designed. For this reason, interest has developed in demonstrating that nuclear plant structures and safety-related systems can safely withstand earthquake ground motion larger than their design earthquake ground motions (SSE and OBE). Within this paper, this larger-than-design earthquake ground motion will be called the seismic margin earthquake (SME) to distinguish it from the design earthquakes. The goal is to determine the performance of already-designed structures, components, and systems when subjected to the SME. Different and generally more liberal criteria should be used when evaluating the performance of structures, components and systems for the SME than were used in design. Retrofit, and redesign, should only be contemplated if one cannot show a seismic margin greater than unity for the SME using these more liberal criteria. In other words, the SME is not a design earthquake. It is not a replacement for the SSE and generally has nothing to do with design. The SME is a performance-check earthquake

  10. Assessment of margins with respect to pressurized thermal shock for the 3 loop plants of the French program

    International Nuclear Information System (INIS)

    Buchalet, C.; Haussaire, P.; Houssin, B.; Vagner, J.

    1983-08-01

    Presentation of the FRAMATOME and EDF program on pressurized thermal shock which objectives are to demonstrate that present and older French reactor vessels have adequate safety margins and to provide recommendations of feasible plant specific modifications, both technically and economically. Phase I consists in a thorough analysis of pressure and temperature transients that the R.P.V. beltine could undergo during plant operations; phase II is the fracture mechanics analysis; phase III estimates the safety margins available during normal, upset, emergency and faulted conditions

  11. Risk evaluation method for faults by engineering approach. (2) Application concept of margin analysis utilizing accident sequences

    International Nuclear Information System (INIS)

    Kamiya, Masanobu; Kanaida, Syuuji; Kamiya, Kouichi; Sato, Kunihiko; Kuroiwa, Katsuya

    2016-01-01

    The influence of the fault displacement on the facility should to be evaluated not only by the activity of the fault but also by obtaining risk information by considering scenarios including such as the frequency and the degree of the hazard, which should be an appropriate approach for nuclear safety. An applicable concept of margin analysis utilizing accident sequences for evaluating the influence of the fault displacement is proposed. By use of this analysis, we can evaluate of the safety functions and margin for core damage, verify the efficiency of equipment of portable type and make a decision to take additional measures to reduce the risk by using obtained risk information. (author)

  12. KHNP special safety review

    International Nuclear Information System (INIS)

    Lee, Tae-Ho; Lee, Bang-Jin; Lee, Soung-Hee; Park, Goon-Cherl

    2009-01-01

    Commemorating the 30 year anniversary of commercial nuclear power plant operation in KOREA, Korea Hydro and Nuclear Power Co., Ltd. (KHNP) has conducted a Special Safety Review (SSR) of its 20 operating units to understand their safety performance and to identify any areas that need improvement. The SSR reviewed all 20 operating units for 2 weeks per site. Areas that were reviewed are Safety Margins, Plant Performance, Employee Safety, Employee Performance and Performance Improvement Process. Each review team consisted of international and domestic members. The international reviewers were from IAEA, WANO and INPO. The domestic reviewers consisted of professors, Engineering Company, Research Institute and KHNP experts. The review confirmed safe and reliable operations of the 20 nuclear units. The common understanding resulted from the SSR is as follows. Firstly, KHNP corporate and its plants confirmed and shared mutual understanding on recurring areas for improvements, especially in the areas of Organizational Effectiveness, Industrial Safety, Human Performance, Configuration Management, Operations, Equipment Performance and Material Condition. Secondly, KHNP understood that plant and department level performances are directly related to the leadership and competency of the management team including supervisors. Thirdly, the strengths of individual stations that consistently have produced good results need to be shared with the other KHNP stations. Finally, KHNP learned that strong corporate leadership and support are needed to resolve most of the areas for improvement since they are common to all KHNP stations. (author)

  13. Fedme og risiko for marginal parodontitis

    DEFF Research Database (Denmark)

    Kongstad, Johanne; Keller, Amélie Cléo; Rohde, Jeanett Friis

    2017-01-01

    Oversigtsartiklen, der er af narrativ karakter, beskriver sammenhængen mellem overvægt/ fedme og marginal parodontitis. Artiklen er baseret på et udvalg af nyere engelsksproget litteratur og motiveres af den øgede forekomst af overvægtige og fede i befolkningen. Desuden er det afgørende, at tandl......Oversigtsartiklen, der er af narrativ karakter, beskriver sammenhængen mellem overvægt/ fedme og marginal parodontitis. Artiklen er baseret på et udvalg af nyere engelsksproget litteratur og motiveres af den øgede forekomst af overvægtige og fede i befolkningen. Desuden er det afgørende......, at tandlæger forholder sig kritisk til systemiske tilstandes mulige konsekvens for udvikling, forværring og behandling af marginal parodontitis. Der nævnes forskellige mål for fedme, hvor body mass index (BMI) og taljeomkreds er de mest anvendte. Problematikken vedrørende tidligere studiers anvendelse af...... forskellige kriterier for marginal parodontitis berøres. Litteraturgennemgangen tager udgangspunkt i de biologiske mekanismer, der udløses i fedtvæv ved overvægt/fedme og medfører en kronisk inflammatorisk tilstand med frigivelse af bl.a. adipokiner. Epidemiologiske tværsnitsog longitudinelle studier af...

  14. Second Language Learners' Use of Marginal Glosses

    Science.gov (United States)

    O'Donnell, Mary E.

    2012-01-01

    The use of marginal reading glosses by 18 second language (L2) learners is examined through a quantitative and qualitative analysis of audiotaped think-aloud protocols. How these readers interact with the glosses is identified and divided into five categories or gloss interactions. Examples from each are presented. The primary research question…

  15. Large margin image set representation and classification

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-07-06

    In this paper, we propose a novel image set representation and classification method by maximizing the margin of image sets. The margin of an image set is defined as the difference of the distance to its nearest image set from different classes and the distance to its nearest image set of the same class. By modeling the image sets by using both their image samples and their affine hull models, and maximizing the margins of the images sets, the image set representation parameter learning problem is formulated as an minimization problem, which is further optimized by an expectation - maximization (EM) strategy with accelerated proximal gradient (APG) optimization in an iterative algorithm. To classify a given test image set, we assign it to the class which could provide the largest margin. Experiments on two applications of video-sequence-based face recognition demonstrate that the proposed method significantly outperforms state-of-the-art image set classification methods in terms of both effectiveness and efficiency.

  16. Early math intervention for marginalized students

    DEFF Research Database (Denmark)

    Overgaard, Steffen; Tonnesen, Pia Beck

    2016-01-01

    This study is one of more substudies in the project Early Math Intervention for Marginalized Students (TMTM2014). The paper presents the initial process of this substudy that will be carried out fall 2015. In the TMTM2014 project, 80 teachers, who completed a one week course in the idea of TMTM...

  17. Mundhulens mikroflora hos patienter med marginal parodontitis

    DEFF Research Database (Denmark)

    Larsen, Tove; Fiehn, Nils-Erik

    2011-01-01

    Viden om marginal parodontitis’ mikrobiologi tog for alvor fart for ca. 40 år siden. Den tidlige viden var baseret på mikroskopiske og dyrkningsmæssige undersøgelser af den subgingivale plak. Anvendelsen af de nyere molekylærbiologiske metoder har betydet, at vor viden om de ætiologiske faktorer ...

  18. Large margin image set representation and classification

    KAUST Repository

    Wang, Jim Jing-Yan; Alzahrani, Majed A.; Gao, Xin

    2014-01-01

    In this paper, we propose a novel image set representation and classification method by maximizing the margin of image sets. The margin of an image set is defined as the difference of the distance to its nearest image set from different classes and the distance to its nearest image set of the same class. By modeling the image sets by using both their image samples and their affine hull models, and maximizing the margins of the images sets, the image set representation parameter learning problem is formulated as an minimization problem, which is further optimized by an expectation - maximization (EM) strategy with accelerated proximal gradient (APG) optimization in an iterative algorithm. To classify a given test image set, we assign it to the class which could provide the largest margin. Experiments on two applications of video-sequence-based face recognition demonstrate that the proposed method significantly outperforms state-of-the-art image set classification methods in terms of both effectiveness and efficiency.

  19. 17 CFR 31.18 - Margin calls.

    Science.gov (United States)

    2010-04-01

    ... transaction merchant is unable to effect personal contact with a leverage customer, a telegram sent to the....18 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION LEVERAGE TRANSACTIONS § 31.18 Margin calls. (a) No leverage transaction merchant shall liquidate a leverage contract because of...

  20. Thinking on the Margin: A Classroom Experiment

    Science.gov (United States)

    Bangs, Joann

    2009-01-01

    One of the most important concepts being taught in principles classes is the idea of "thinking on the margin." It can also be one of the most difficult to get across. One of the most telling examples, according to this author, comes in trying to get students to learn the profit maximizing condition for perfectly competitive firms. She…

  1. Estimation of marginal costs at existing waste treatment facilities.

    Science.gov (United States)

    Martinez-Sanchez, Veronica; Hulgaard, Tore; Hindsgaul, Claus; Riber, Christian; Kamuk, Bettina; Astrup, Thomas F

    2016-04-01

    This investigation aims at providing an improved basis for assessing economic consequences of alternative Solid Waste Management (SWM) strategies for existing waste facilities. A bottom-up methodology was developed to determine marginal costs in existing facilities due to changes in the SWM system, based on the determination of average costs in such waste facilities as function of key facility and waste compositional parameters. The applicability of the method was demonstrated through a case study including two existing Waste-to-Energy (WtE) facilities, one with co-generation of heat and power (CHP) and another with only power generation (Power), affected by diversion strategies of five waste fractions (fibres, plastic, metals, organics and glass), named "target fractions". The study assumed three possible responses to waste diversion in the WtE facilities: (i) biomass was added to maintain a constant thermal load, (ii) Refused-Derived-Fuel (RDF) was included to maintain a constant thermal load, or (iii) no reaction occurred resulting in a reduced waste throughput without full utilization of the facility capacity. Results demonstrated that marginal costs of diversion from WtE were up to eleven times larger than average costs and dependent on the response in the WtE plant. Marginal cost of diversion were between 39 and 287 € Mg(-1) target fraction when biomass was added in a CHP (from 34 to 303 € Mg(-1) target fraction in the only Power case), between -2 and 300 € Mg(-1) target fraction when RDF was added in a CHP (from -2 to 294 € Mg(-1) target fraction in the only Power case) and between 40 and 303 € Mg(-1) target fraction when no reaction happened in a CHP (from 35 to 296 € Mg(-1) target fraction in the only Power case). Although average costs at WtE facilities were highly influenced by energy selling prices, marginal costs were not (provided a response was initiated at the WtE to keep constant the utilized thermal capacity). Failing to systematically

  2. Orogenic structural inheritance and rifted passive margin formation

    Science.gov (United States)

    Salazar Mora, Claudio A.; Huismans, Ritske S.

    2016-04-01

    Structural inheritance is related to mechanical weaknesses in the lithosphere due to previous tectonic events, e.g. rifting, subduction and collision. The North and South Atlantic rifted passive margins that formed during the breakup of Western Gondwana, are parallel to the older Caledonide and the Brasiliano-Pan-African orogenic belts. In the South Atlantic, 'old' mantle lithospheric fabric resulting from crystallographic preferred orientation of olivine is suggested to play a role during rifted margin formation (Tommasi and Vauchez, 2001). Magnetometric and gravimetric mapping of onshore structures in the Camamu and Almada basins suggest that extensional faults are controlled by two different directions of inherited older Brasiliano structures in the upper lithosphere (Ferreira et al., 2009). In the South Atlantic Campos Basin, 3D seismic data indicate that inherited basement structures provide a first order control on basin structure (Fetter, 2009). Here we investigate the role of structural inheritance on the formation of rifted passive margins with high-resolution 2D thermo-mechanical numerical experiments. The numerical domain is 1200 km long and 600 km deep and represents the lithosphere and the sublithospheric mantle. Model experiments were carried out by creating self-consistent orogenic inheritance where a first phase of orogen formation is followed by extension. We focus in particular on the role of varying amount of orogenic shortening, crustal rheology, contrasting styles of orogen formation on rifted margin style, and the time delay between orogeny and subsequent rifted passive formation. Model results are compared to contrasting structural styles of rifted passive margin formation as observed in the South Atlantic. Ferreira, T.S., Caixeta, J.M., Lima, F.D., 2009. Basement control in Camamu and Almada rift basins. Boletim de Geociências da Petrobrás 17, 69-88. Fetter, M., 2009. The role of basement tectonic reactivation on the structural evolution

  3. Tectonostratigraphy of the Passive Continental Margin Offshore Indus Pakistan

    Science.gov (United States)

    Aslam, K.; Khan, M.; Liu, Y.; Farid, A.

    2017-12-01

    The tectonic evolution and structural complexities are poorly understood in the passive continental margin of the Offshore Indus of Pakistan. In the present study, an attempt has been made to interpret the structural trends and seismic stratigraphic framework in relation to the tectonics of the region. Seismic reflection data revealed tectonically controlled, distinct episodes of normal faulting representing rifting at different ages and transpression in the Late Eocene time. This transpression has resulted in the reactivation of the Pre-Cambrian basement structures. The movement of these basement structures has considerably affected the younger sedimentary succession resulting in push up structures resembling anticlines. The structural growth of the push-up structures was computed. The most remarkable tectonic setting in the region is represented by the normal faulting and by the basement uplift which divides the rifting and transpression stages. Ten mappable seismic sequences have been identified on the seismic records. A Jurassic aged paleo-shelf has also been identified on all regional seismic profiles which is indicative of Indian-African Plates separation during the Jurassic time. Furthermore, the backstripping technique was applied which has been proved to be a powerful technique to quantify subsidence/uplift history of rift-type passive continental margins. The back strip curves suggest that transition from an extensional rifted margin to transpression occurred during Eocene time (50-30 Ma). The backstripping curves show uplift had happened in the area. We infer that the uplift has occurred due to the movement of basement structures by the transpression movements of Arabian and Indian Plates. The present study suggests that the structural styles and stratigraphy of the Offshore Indus Pakistan were significantly affected by the tectonic activities during the separation of Gondwanaland in the Mesozoic and northward movement of the Indian Plate, post

  4. Central-marginal population dynamics in species invasions

    Directory of Open Access Journals (Sweden)

    Qinfeng eGuo

    2014-06-01

    Full Text Available The species’ range limits and associated central-marginal (C-M; i.e., from species range center to margin population dynamics continue to draw increasing attention because of their importance for current emerging issues such as biotic invasions and epidemic diseases under global change. Previous studies have mainly focused on species borders and C-M process in natural settings for native species. More recently, growing efforts are devoted to examine the C-M patterns and process for invasive species partly due to their relatively short history, highly dynamic populations, and management implications. Here I examine recent findings and information gaps related to (1 the C-M population dynamics linked to species invasions, and (2 the possible effects of climate change and land use on the C-M patterns and processes. Unlike most native species that are relatively stable (some even having contracting populations or ranges, many invasive species are still spreading fast and form new distribution or abundance centers. Because of the strong nonlinearity of population demographic or vital rates (i.e. birth, death, immigration and emigration across the C-M gradients and the increased complexity of species ranges due to habitat fragmentation, multiple introductions, range-wide C-M comparisons and simulation involving multiple vital rates are needed in the future.

  5. The Seismicity of Two Hyperextended Margins

    Science.gov (United States)

    Redfield, Tim; Terje Osmundsen, Per

    2013-04-01

    A seismic belt marks the outermost edge of Scandinavia's proximal margin, inboard of and roughly parallel to the Taper Break. A similar near- to onshore seismic belt runs along its inner edge, roughly parallel to and outboard of the asymmetric, seaward-facing escarpment. The belts converge at both the northern and southern ends of Scandinavia, where crustal taper is sharp and the proximal margin is narrow. Very few seismic events have been recorded on the intervening, gently-tapering Trøndelag Platform. Norway's distribution of seismicity is systematically ordered with respect to 1) the structural templates of high-beta extension that shaped the thinning gradient during Late Jurassic or Early Cretaceous time, and 2) the topographically resurgent Cretaceous-Cenozoic "accommodation phase" family of escarpments that approximate the innermost limit of crustal thinning [See Redfield and Osmundsen (2012) for diagrams, definitions, discussion, and supporting citations.] Landwards from the belt of earthquake epicenters that mark the Taper Break the crust consistently thickens, and large fault arrays tend to sole out at mid crustal levels. Towards the sea the crystalline continental crust is hyperextended, pervasively faulted, and generally very thin. Also, faulting and serpentinization may have affected the uppermost parts of the distal margin's lithospheric mantle. Such contrasting structural conditions may generate a contrasting stiffness: for a given stress, more strain can be accommodated in the distal margin than in the less faulted proximal margin. By way of comparison, inboard of the Taper Break on the gently-tapered Trøndelag Platform, faulting was not penetrative. There, similar structural conditions prevail and proximal margin seismicity is negligible. Because stress concentration can occur where material properties undergo significant contrast, the necking zone may constitute a natural localization point for post-thinning phase earthquakes. In Scandinavia

  6. Periodic safety analyses; Les essais periodiques

    Energy Technology Data Exchange (ETDEWEB)

    Gouffon, A; Zermizoglou, R

    1990-12-01

    The IAEA Safety Guide 50-SG-S8 devoted to 'Safety Aspects of Foundations of Nuclear Power Plants' indicates that operator of a NPP should establish a program for inspection of safe operation during construction, start-up and service life of the plant for obtaining data needed for estimating the life time of structures and components. At the same time the program should ensure that the safety margins are appropriate. Periodic safety analysis are an important part of the safety inspection program. Periodic safety reports is a method for testing the whole system or a part of the safety system following the precise criteria. Periodic safety analyses are not meant for qualification of the plant components. Separate analyses are devoted to: start-up, qualification of components and materials, and aging. All these analyses are described in this presentation. The last chapter describes the experience obtained for PWR-900 and PWR-1300 units from 1986-1989.

  7. CRBRP structural and thermal margin beyond the design base

    International Nuclear Information System (INIS)

    Strawbridge, L.E.

    1979-01-01

    Prudent margins beyond the design base have been included in the design of Clinch River Breeder Reactor Plant to further reduce the risk to the public from highly improbable occurrences. These margins include Structural Margin Beyond the Design Base to address the energetics aspects and Thermal Margin Beyond the Design Base to address the longer term thermal and radiological consequences. The assessments that led to the specification of these margins are described, along with the experimental support for those assessments. 8 refs

  8. Consideration of margins for hypo fractionated radiotherapy

    International Nuclear Information System (INIS)

    Herschtal, A.; Foroudi, F.; Kron, T.

    2010-01-01

    Full text: Geographical misses of the tumour are of concern in radiotherapy and are typically accommodated by introducing margins around the target. However, there is a trade-off between ensuring the target receives sufficient dose and minimising the dose to surrounding normal structures. Several methods of determining margin width have been developed with the most commonly used one proposed by M. VanHerk (VanHerk UROBP 52: 1407, 2002). VanHerk's model sets margins to achieve 95% of dose coverage for the target in 90% of patients. However, this model was derived assuming an infinite number of fractions. The aim of the present work is to estimate the modifications necessary to the model if a finite number of fractions are given. Software simulations were used to determine the true probability of a patient achieving 95% target coverage if different fraction numbers are used for a given margin width. Model parameters were informed by a large data set recently acquired at our institution using daily image guidance for prostate cancer patients with implanted fiducial markers. Assuming a 3 mm penumbral width it was found that using the VanHerk model only 74 or 54% of patients receive 95% of the prescription dose if 20 or 6 fractions are given, respectively. The steep dose gradients afforded by IMRT are likely to make consideration of the effects of hypofractionation more important. It is necessary to increase the margins around the target to ensure adequate tumour coverage if hypofractionated radiotherapy is to be used for cancer treatment. (author)

  9. Safety first

    Energy Technology Data Exchange (ETDEWEB)

    Harvie, W.

    1997-06-01

    Expansion of international business opportunities for Canadian producers and service companies brings with it a dimension almost never considered on home base - security. It was pointed out that once abroad, safety and defence of people and equipment can become significant problems in many parts of the world. The nature of the security risks involved, and how best to deal with them, were discussed. The use of consultants, mostly foreign ones to date, and the kind of assistance they can provide, everything from written reports on the local situation to counter surveillance training, and bodyguard services, have been described. Examples of recent involvements with guerilla groups demanding `revolutionary war taxes`, kidnapping executives for ransom, due diligence investigations of potential partners, and the like, have been provided to illustrate the unique character of the problem, and the constant need for being alert, educated to risks, and being prepared to react to risk situations.

  10. General principles of nuclear safety management related to research reactor decommissioning

    International Nuclear Information System (INIS)

    Banciu, Ortenzia; Vladescu, Gabriela

    2003-01-01

    The paper contents the general principles applicable to the decommissioning of research reactors to ensure a proper nuclear safety management, during both decommissioning activities and post decommissioning period. The main objective of decommissioning is to ensure the protection of workers, population and environment against all radiological and non-radiological hazards that could result after a reactor shutdown and dismantling. In the same time, it is necessary, by some proper provisions, to limit the effect of decommissioning for the future generation, according to the new Romanian, IAEA and EU Norms and Regulations. Assurance of nuclear safety during decommissioning process involves, in the first step, to establish of some safety principles and requirements to be taken into account during whole process. In the same time, it is necessary to perform a series of analyses to ensure that the whole process is conducted in a planned and safe manner. The general principles proposed for a proper management of safety during research reactor decommissioning are as follows: - Set-up of all operations included in a Decommissioning Plan; - Set-up and qualitative evaluation of safety problems, which could appear during normal decommissioning process, both radiological and nonradiological risks for workers and public; - Set-up of accident list related to decommissioning process the events that could appear both due to some abnormal working conditions and to some on-site and off-site events like fires, explosions, flooding, earthquake, etc.); - Development and qualitative/ quantitative evaluation of scenarios for each incidents; - Development (and evaluation) of safety indicator system. The safety indicators are the most important tools used to assess the level of nuclear safety during decommissioning process, to discover the weak points and to establish safety measures. The paper contains also, a safety case evaluation (description of facility according to the decommissioning

  11. Reactor safety

    International Nuclear Information System (INIS)

    Butz, H.P.; Heuser, F.W.; May, H.

    1985-01-01

    The paper comprises an introduction into nuclear physics bases, the safety concept generally speaking, safety devices of pwr type reactors, accident analysis, external influences, probabilistic safety assessment and risk studies. It further describes operational experience, licensing procedures under the Atomic Energy Law, research in reactor safety and the nuclear fuel cycle. (DG) [de

  12. Additional safety assessment of common means or support of the Marcoule centre

    International Nuclear Information System (INIS)

    2012-01-01

    This report first presents some characteristics of the Marcoule centre: location and environment, base nuclear installations and other installations, technical installations and installations classified for protection of the environment which could affect the safety of nearby installations, demographic and industrial environment and risks generated for the site's installations, general description of crisis management means. The second part addresses situations to be considered, functional needs related to additional safety assessments, needs in terms of support functions, and critical structures and equipment. The next parts address the seismic risk (structure and equipment sizing, margin assessment, flooding due to an earthquake, loss of electric supply due to an earthquake), the flooding risk (flooding sources, main alarm measures, structure and equipment sizing and availability for crisis management during a flooding from different origins), other extreme phenomena (lightning, hail, wind, external fire), the loss of electric supplies and the loss of cooling systems, the organisation of accident management, and subcontracting practices

  13. A randomized, double-blind, comparative study to assess the safety and efficacy of topical retapamulin ointment 1% versus oral linezolid in the treatment of secondarily infected traumatic lesions and impetigo due to methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Tanus, Tonny; Scangarella-Oman, Nicole E; Dalessandro, Marybeth; Li, Gang; Breton, John J; Tomayko, John F

    2014-12-01

    To evaluate the clinical and bacteriological efficacy of topical retapamulin ointment 1% versus oral linezolid in the treatment of patients with secondarily infected traumatic lesions (SITLs; excluding abscesses) or impetigo due to methicillin-resistant Staphylococcus aureus (MRSA). A randomized, double-blind, double-dummy, multicenter, comparative study (NCT00852540). Patients recruited from 36 study centers in the United States. Patients 2 months or older with SITL (including secondarily infected lacerations or sutured wounds) or impetigo (bullous and nonbullous) suitable for treatment with a topical antibiotic, with a total Skin Infection Rating Scale score of 8 or greater, including a pus/exudate score of 3 or greater. Patients received retapamulin ointment 1% (plus oral placebo), twice daily for 5 days or oral linezolid (plus placebo ointment) 2 or 3 times daily for 10 days. Primary end point: clinical response (success/failure) at follow-up in patients with MRSA at baseline (per-protocol population). Secondary efficacy end points: clinical and microbiologic response and outcome at follow-up and end of therapy; therapeutic response at follow-up. The majority of patients had SITL (70.4% [188/267] and 66.4% [91/137] in the retapamulin and linezolid groups, respectively; intent-to-treat clinical population). Clinical success rate at follow-up was significantly lower in the retapamulin versus the linezolid group (63.9% [39/61] vs 90.6% [29/32], respectively; difference in success rate -26.7%; 95% CI, -45.7 to -7.7). Clinical success rate at follow-up in the per-protocol MRSA population was significantly lower in the retapamulin versus the linezolid group. It could not be determined whether this was related to study design, bacterial virulence, or retapamulin activity.

  14. Thermal Margin Calculation of the CAREM-25 Core

    International Nuclear Information System (INIS)

    Mazufri, C.M

    2000-01-01

    During the operation in steady state and anticipated operational transient of a nuclear reactor it is necessary to avoid the damage in the fuel elements induced by thermal or hydraulic effects.To satisfy that design bases safety limits are established and calculation methodologies are defined to verify them.In the particular case of the reactor CAREM-25 reactor where the core is cooled by natural circulation, it is not adequate to use directly the same calculation methodologies from typical PWR and BWR.The low cooling flow rate and not having channels in the fuel elements (open-channel fuels) produce that most of the models and computer programs typically used must be carefully validated.As result of that process, an adequate calculation procedure for this reactor type was developed.In the present work, the thermal-hydraulic design criteria of the core and the design bases, the uncertainties factors, and the thermal margin results of the core are described.Despite that the methodology of DNBR calculation is under a validation process and considering the available calculation tools, it is possible to assure that the core fulfills the safety regulations in steady state conditions

  15. A procedure for safety assessment of components with cracks - Handbook

    International Nuclear Information System (INIS)

    Andersson, P.; Bergman, M.; Brickstad, B.; Dahlberg, L.; Nilsson, F.; Sattari-Far, I.

    1996-01-01

    In this handbook a procedure is described which can be used both for assessment of detected cracks or crack like defects or for defect tolerance analysis. The procedure can be used to calculate possible crack growth due to fatigue or stress corrosion and to calculate the reserve margin for failure due to fracture and plastic collapse. For ductile materials, the procedure gives the reserve margin for initiation of stable crack growth. Thus, an extra reserve margin, unknown to size, exists for failure in components made of ductile materials. The procedure was developed for operative use with the following objectives in mind: The procedure should be able to handle both linear and non-linear problems without any a priori division; The procedure shall ensure uniqueness of the safety assessment; The procedure should be well defined and easy to use; The conservatism of the procedure should be well validated; The handbook that documents the procedure should be so complete that for most assessments access to any other fracture mechanics literature should not be necessary. The method utilized is based on the R6-method developed at Nuclear Electric plc. This method can in principle be used for all metallic materials. It is, however, more extensively verified for steel alloys only. The method is not intended for use in temperatures where creep deformation is of importance. The first edition of the handbook was released in 1990 and the second in 1991. This third edition has been extensively revised. A Windows-based program (SACC) has been developed which can perform the assessments described in the book including calculation of crack growth due to stress corrosion and fatigue. 52 refs., 27 figs., 35 tabs

  16. Perspective channel-type reactor with enhanced safety

    International Nuclear Information System (INIS)

    Adamov, E.O.; Grozdov, I.I.; Kuznetsov, S.P.; Petrov, A.A.; Rozhdestvensky, M.I.; Cherkashov, Yu.M.

    1994-01-01

    Following the search for new design solutions to develop within the framework of channel trends the reactor with enhanced safety the Research and Development Institute of Power Engineering has developed the design of the multiloop boiling water reactor (MKER). The MKER enhanced safety is attained when involving the inherent safety features, passive safety systems as well as the accident consequences confinement devices. The design realizes several advantages which are typical of the channel-type reactors, namely: The design desintegration simplifying the manufacture, control, equipment delivery and decreasing, versus the pressure vessel reactors, the accident effect if it proceeds in an explosive manner; small operating reactivity margin and fuel burnup increased due to continuous refuelling; fuel cycle flexibility allowing comparatively easily to adopt the reactor to the conjuncture of the country fuel balance; multiloop circuit of the main coolant which reduces the degree and effect of the accidents connected with the equipment and pipings rupture; monitoring of the channels and fuel assemblies leak-tightness. (orig.)

  17. Regulatory practices of radiation safety of SNF transportation in Russia

    International Nuclear Information System (INIS)

    Kuryndina, Lidia; Kuryndin, Anton; Stroganov, Anatoly

    2008-01-01

    This paper overviews current regulatory practices for the assurance of nuclear and radiation safety during railway transportation of SNF on the territory of Russian Federation from NPPs to longterm-storage of reprocessing sites. The legal and regulatory requirements (mostly compliant with IAEA ST-1), licensing procedure for NM transportation are discussed. The current procedure does not require a regulatory approval for each particular shipment if the SNF fully comply with the Rosatom's branch standard and is transported in approved casks. It has been demonstrated that SNF packages compliant with the branch standard, which is knowingly provide sufficient safety margin, will conform to the federal level regulations. The regulatory approval is required if a particular shipment does not comply with the branch standard. In this case, the shipment can be approved only after regulatory review of Applicant's documents to demonstrate that the shipment still conformant to the higher level (federal) regulations. The regulatory review frequently needs a full calculation test of the radiation safety assurance. This test can take a lot of time. That's why the special calculation tools were created in SEC NRS. These tools aimed for precision calculation of the radiation safety parameters by SNF transportation use preliminary calculated Green's functions. Such approach allows quickly simulate any source distribution and optimize spent fuel assemblies placement in cask due to the transport equation property of linearity relatively the source. The short description of calculation tools are presented. Also, the paper discusses foreseen implications related to transportation of mixed-oxide SNF. (author)

  18. Seaward dipping reflectors along the SW continental margin of India: Evidence for volcanic passive margin

    Digital Repository Service at National Institute of Oceanography (India)

    Ajay, K.K.; Chaubey, A.K.; Krishna, K.S.; Rao, D.G.; Sar, D.

    Multi-channel seismic reflection profiles across the southwest continental margin of India (SWCMI) show presence of westerly dipping seismic reflectors beneath sedimentary strata along the western flank of the Laccadive Ridge-northernmost part...

  19. Conference Report: The New Discovery of Margins: Theory-Based Excursions in Marginal Social Fields

    Directory of Open Access Journals (Sweden)

    Babette Kirchner

    2014-05-01

    Full Text Available At this year's spring conference of the Sociology of Knowledge Section of the German Sociological Association, a diverse range of theoretical concepts and multiple empirical insights into different marginal social fields were presented. As in everyday life, drawing a line between center and margin can be seen as an important challenge that must equally be faced in sociology. The socially constructed borderline appears to be highly variable. Therefore it has to be delineated or fixed somehow. The construction of margins is necessary for society in general and smaller social groupings alike to confirm one's own "normal" identity, or one's own membership on the fringes. The different contributions exemplify what was established at the beginning of the conference: Namely that society and its margins are defined differently according to the empirical as well as conceptual focus. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1402148

  20. The Accident Analysis Due to Reactivity Insertion of RSG GAS 3.55 g U/cc Silicide Core

    International Nuclear Information System (INIS)

    Endiah Puji-Hastuti; Surbakti, Tukiran

    2004-01-01

    The fuels of RSG-GAS reactor was changed from uranium oxide with 250 g U of loading or 2.96 g U/cc of fuel loading to uranium silicide with the same loading. The silicide fuels can be used in higher density, staying longer in the reactor core and hence having a longer cycle length. The silicide fuel in RSG-GAS core was made up in step-wise by using mixed up core Firstly, it was used silicide fuel with 250 g U of loading and then, silicide fuel with 300 g U of loading (3.55 g U/cc of fuel loading). In every step-wise of fuel loading, it must be analyzed its safety margin. In this occasion, the reactivity accident of RSG-GAS core with 300 g U of silicide fuel loading is analyzed. The calculation was done using EUREKA-2/RR code available at P2TRR. The calculation was done by reactivity insertion at start up and power rangers. The worst case accident is transient due to control rod with drawl failure at start up by means of lowest initial power (0.1 W), either in power range. From all cases which have been done, the results of analysis showed that there is no anomaly and safety margin break at RSG-GAS core with 300 g U silicide fuel loading. (author)

  1. Safety of huge systems

    International Nuclear Information System (INIS)

    Kondo, Jiro.

    1995-01-01

    Recently accompanying the development of engineering technology, huge systems tend to be constructed. The disaster countermeasures of huge cities become large problems as the concentration of population into cities is conspicuous. To make the expected value of loss small, the knowledge of reliability engineering is applied. In reliability engineering, even if a part of structures fails, the safety as a whole system must be ensured, therefore, the design having margin is carried out. The degree of margin is called redundancy. However, such design concept makes the structure of a system complex, and as the structure is complex, the possibility of causing human errors becomes high. At the time of huge system design, the concept of fail-safe is effective, but simple design must be kept in mind. The accident in Mihama No. 2 plant of Kansai Electric Power Co. and the accident in Chernobyl nuclear power station, and the accident of Boeing B737 airliner and the fatigue breakdown are described. The importance of safety culture was emphasized as the method of preventing human errors. Man-system interface and management system are discussed. (K.I.)

  2. Decoding the Margins: What Can the Fractal Geometry of Basaltic Flow Margins Tell Us?

    Science.gov (United States)

    Schaefer, E. I.; Hamilton, C.; Neish, C.; Beard, S. P.; Bramson, A. M.; Sori, M.; Rader, E. L.

    2016-12-01

    Studying lava flows on other planetary bodies is essential to characterizing eruption styles and constraining the bodies' thermal evolution. Although planetary basaltic flows are common, many key features are not resolvable in orbital imagery. We are thus developing a technique to characterize basaltic flow type, sub-meter roughness, and sediment mantling from these data. We will present the results from upcoming fieldwork at Craters of the Moon National Monument and Preserve with FINESSE (August) and at Hawai'i Volcanoes National Park (September). We build on earlier work that showed that basaltic flow margins are approximately fractal [Bruno et al., 1992; Gaonac'h et al., 1992] and that their fractal dimensions (D) have distinct `a`ā and pāhoehoe ranges under simple conditions [Bruno et al., 1994]. Using a differential GPS rover, we have recently shown that the margin of Iceland's 2014 Holuhraun flow exhibits near-perfect (R2=0.9998) fractality for ≥24 km across dm to km scales [Schaefer et al., 2016]. This finding suggests that a fractal-based technique has significant potential to characterize flows at sub-resolution scales. We are simultaneously seeking to understand how margin fractality can be modified. A preliminary result for an `a'ā flow in Hawaii's Ka'ū Desert suggests that although aeolian mantling obscures the original flow margin, the apparent margin (i.e., sediment-lava interface) remains fractal [Schaefer et al., 2015]. Further, the apparent margin's D is likely significantly modified from that of the original margin. Other factors that we are exploring include erosion, transitional flow types, and topographic confinement. We will also rigorously test the intriguing possibility that margin D correlates with the sub-meter Hurst exponent H of the flow surface, a common metric of roughness scaling [e.g., Shepard et al., 2001]. This hypothesis is based on geometric arguments [Turcotte, 1997] and is qualitatively consistent with all results so far.

  3. Conference Report: The New Discovery of Margins: Theory-Based Excursions in Marginal Social Fields

    OpenAIRE

    Kirchner, Babette; Lorenzen, Jule-Marie; Striffler, Christine

    2014-01-01

    At this year's spring conference of the Sociology of Knowledge Section of the German Sociological Association, a diverse range of theoretical concepts and multiple empirical insights into different marginal social fields were presented. As in everyday life, drawing a line between center and margin can be seen as an important challenge that must equally be faced in sociology. The socially constructed borderline appears to be highly variable. Therefore it has to be delineated or fixed somehow. ...

  4. The marginal band system in nymphalid butterfly wings.

    Science.gov (United States)

    Taira, Wataru; Kinjo, Seira; Otaki, Joji M

    2015-01-01

    Butterfly wing color patterns are highly complex and diverse, but they are believed to be derived from the nymphalid groundplan, which is composed of several color pattern systems. Among these pattern systems, the marginal band system, including marginal and submarginal bands, has rarely been studied. Here, we examined the color pattern diversity of the marginal band system among nymphalid butterflies. Marginal and submarginal bands are usually expressed as a pair of linear bands aligned with the wing margin. However, a submarginal band can be expressed as a broken band, an elongated oval, or a single dot. The marginal focus, usually a white dot at the middle of a wing compartment along the wing edge, corresponds to the pupal edge spot, one of the pupal cuticle spots that signify the locations of color pattern organizing centers. A marginal band can be expressed as a semicircle, an elongated oval, or a pair of eyespot-like structures, which suggest the organizing activity of the marginal focus. Physical damage at the pupal edge spot leads to distal dislocation of the submarginal band in Junonia almana and in Vanessa indica, suggesting that the marginal focus functions as an organizing center for the marginal band system. Taken together, we conclude that the marginal band system is developmentally equivalent to other symmetry systems. Additionally, the marginal band is likely a core element and the submarginal band a paracore element of the marginal band system, and both bands are primarily specified by the marginal focus organizing center.

  5. EPRI program in water reactor safety

    International Nuclear Information System (INIS)

    Loewenstein, W.B.; Gelhaus, F.; Gopalakrishnan, A.

    1975-01-01

    The basis for EPRI's water reactor safety program is twofold. First is compilation and development of fundamental background data necessary for quantified light-water reactor (LWR) safety assurance appraisals. Second is development of realistic and experimentally bench-marked analytical procedures. The results are expected either to confirm the safety margins in current operating parameters, and to identify overly conservative controls, or, in some cases, to provide a basis for improvements to further minimize uncertainties in expected performance. Achievement of these objectives requires the synthesis of related current and projected experimental-analytical projects toward establishment of an experimentally-based analysis for the assurance of safety for LWRs

  6. American National Standard: for safety in conducting subcritical neutron-multiplication measurements in-situ

    International Nuclear Information System (INIS)

    1983-01-01

    This standard provides safety guidance for conducting subcritical neutron-multiplication measurements where physical protection of personnel against the consequences of a criticality accident is not provided. The objectives of in-situ measurements are either to confirm an adequate safety margin or to improve an estimate of such a margin. The first objective may constitute a test of the criticality safety of a design that is based on calculations. The second may effect improved operating conditions by reducing the uncertainty of safety margins and providing guidance to new designs

  7. The stability margin of elongated plasmas

    International Nuclear Information System (INIS)

    Portone, Alfredo

    2005-01-01

    Passive stabilization is a key feature in tokamak design since it indicates the efficiency of the metallic structures to 'oppose' plasma displacements. As far as plasma vertical displacement modes are concerned, usually their passive stabilization is characterized in terms of two main indices, namely the instability growth time and the stability margin. In this study-after recalling the governing equations-we extend the definition of the stability margin given in the literature (Lazarus E. et al 1990 Nucl. Fusion 30 111, Albanese R. et al 1990 IEEE Trans. Magn. 26, Kameari A. et al 1985 Nucl. Eng. Des./Fusion 365-73) for the rigid body displacement model to the non-rigid plasma model. Numerical examples are also given for the reduced task objectives/reduced cost ITER design

  8. Passive target tracking using marginalized particle filter

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A marginalized particle filtering(MPF)approach is proposed for target tracking under the background of passive measurement.Essentially,the MPF is a combination of particle filtering technique and Kalman filter.By making full use of marginalization,the distributions of the tractable linear part of the total state variables are updated analytically using Kalman filter,and only the lower-dimensional nonlinear state variable needs to be dealt with using particle filter.Simulation studies are performed on an illustrative example,and the results show that the MPF method leads to a significant reduction of the tracking errors when compared with the direct particle implementation.Real data test results also validate the effectiveness of the presented method.

  9. Jatropha potential on marginal land in Ethiopia

    DEFF Research Database (Denmark)

    Wendimu, Mengistu Assefa

    narrative. But both the availability and suitability of “marginal” land for commercial level jatropha production is not well understood/examined, especially in Africa. Using a case study of large-scale jatropha plantation in Ethiopia, this paper examines the process of land identification for jatropha....... The increasing trend of land acquisition for biofuels has led to the widespread debate about food versus biofuel because of the perceived competition for land and water. To avoid the food versus fuel debate, the use of “marginal” land for biofuel feedstock production (jatropha) has emerged as a dominant...... investments, and the agronomic performance of large-scale jatropha plantation on so-called marginal land. Although it has been argued that jatropha can be grown well on marginal land without irrigation, and thus does not compete for land and water or displace food production from agricultural land, this study...

  10. Distributions with given marginals and statistical modelling

    CERN Document Server

    Fortiana, Josep; Rodriguez-Lallena, José

    2002-01-01

    This book contains a selection of the papers presented at the meeting `Distributions with given marginals and statistical modelling', held in Barcelona (Spain), July 17-20, 2000. In 24 chapters, this book covers topics such as the theory of copulas and quasi-copulas, the theory and compatibility of distributions, models for survival distributions and other well-known distributions, time series, categorical models, definition and estimation of measures of dependence, monotonicity and stochastic ordering, shape and separability of distributions, hidden truncation models, diagonal families, orthogonal expansions, tests of independence, and goodness of fit assessment. These topics share the use and properties of distributions with given marginals, this being the fourth specialised text on this theme. The innovative aspect of the book is the inclusion of statistical aspects such as modelling, Bayesian statistics, estimation, and tests.

  11. Marginal Loss Calculations for the DCOPF

    Energy Technology Data Exchange (ETDEWEB)

    Eldridge, Brent [Federal Energy Regulatory Commission, Washington, DC (United States); Johns Hopkins Univ., Baltimore, MD (United States); O' Neill, Richard P. [Federal Energy Regulatory Commission, Washington, DC (United States); Castillo, Andrea R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-12-05

    The purpose of this paper is to explain some aspects of including a marginal line loss approximation in the DCOPF. The DCOPF optimizes electric generator dispatch using simplified power flow physics. Since the standard assumptions in the DCOPF include a lossless network, a number of modifications have to be added to the model. Calculating marginal losses allows the DCOPF to optimize the location of power generation, so that generators that are closer to demand centers are relatively cheaper than remote generation. The problem formulations discussed in this paper will simplify many aspects of practical electric dispatch implementations in use today, but will include sufficient detail to demonstrate a few points with regard to the handling of losses.

  12. The rifted margin of Saudi Arabia

    Science.gov (United States)

    McClain, J. S.; Orcutt, J. A.

    The structure of rifted continental margins has always been of great scientific interest, and now, with dwindling economic oil deposits, these complex geological features assume practical importance as well. The ocean-continent transition is, by definition, laterally heterogeneous and likely to be extremely complicated. The southernmost shotpoints (4, 5, and 6) in the U.S. Geological Survey seismic refraction profile in the Kingdom of Saudi Arabia lie within a transition region and thus provide a testing ground for methods that treat wave propagation in laterally heterogeneous media. This portion of the profile runs from the Farasan Islands in the Red Sea across the coast line and the Hijaz-Asir escarpment into the Hijaz-Asir tectonic province. Because the southernmost shotpoint is within the margin of the Saudi sub-continent, the full transition region is not sampled. Furthermore, such an experiment is precluded by the narrowness of the purely oceanic portion of the Red Sea.

  13. Safety issues on advanced fuel

    International Nuclear Information System (INIS)

    Gross, H.; Krebs, W.D.

    1998-01-01

    In the recent years a general discussion has started whether unsolved safety issues are related to advanced fuel. Advanced fuel is in this context a summary of features like high burnup, improved clad materials, low leakage loading pattern with high peaking factors etc. The design basis accidents RIA and Loca are of special interest for this discussion. From the Siemens point of view RIA is not a safety issue. There are sufficient margins between the enthalpy rise calculated by modern 3D methods and the fuel failures which occurred in RIA simulation tests when the effect of pulse width is taken into account. The evaluation of possible uncertainties for the established Loca criteria (17% equivalent corrosion, 1200 C clad temperature) for high burnup makes sense. But fuel with high burnup has significantly lower peaking factors than fuel with lower burnup. This gives sufficient margin counterbalancing possible uncertainties. In contrast to the above incomplete control rod insertion at higher burnup is potentially a real safety issue. Although Siemens fuel was not affected by the reported incidents they addressed the problem and checked that they have sufficient design margin for their fuel. (orig.) [de

  14. Systems considerations in seismic margin evaluations

    International Nuclear Information System (INIS)

    Buttermer, D.R.

    1987-01-01

    Increasing knowledge in the geoscience field has led to the understanding that, although highly unlikely, it is possible for a nuclear power plant to be subjected to earthquake ground motion greater than that for which the plant was designed. While it is recognized that there are conservatisms inherent in current design practices, interest has developed in evaluating the seismic risk of operating plants. Several plant-specific seismic probabilistic risk assessments (SPRA) have been completed to address questions related to the seismic risk of a plant. The results from such SPRAs are quite informative, but such studies may entail a considerable amount of expensive analysis of large portions of the plant. As an alternative to an SPRA, it may be more practical to select an earthquake level above the design basis for which plant survivability is to be demonstrated. The principal question to be addressed in a seismic margin evaluation is: At what ground motion levels does one have a high confidence that the probability of seismically induced core damage is sufficiently low? In a seismic margin evaluation, an earthquake level is selected (based on site-specific geoscience considerations) for which a stable, long-term safe shutdown condition is to be demonstrated. This prespecified earthquake level is commonly referred to as the seismic margin earthquake (SME). The Electric Power Research Institute is currently supporting a research project to develop procedures for use by the utilities to allow them to perform nuclear plant seismic margin evaluations. This paper describes the systems-related aspects of these procedures

  15. Marginal longitudinal semiparametric regression via penalized splines

    KAUST Repository

    Al Kadiri, M.

    2010-08-01

    We study the marginal longitudinal nonparametric regression problem and some of its semiparametric extensions. We point out that, while several elaborate proposals for efficient estimation have been proposed, a relative simple and straightforward one, based on penalized splines, has not. After describing our approach, we then explain how Gibbs sampling and the BUGS software can be used to achieve quick and effective implementation. Illustrations are provided for nonparametric regression and additive models.

  16. Origins of saline fluids at convergent margins

    Science.gov (United States)

    Martin, Jonathan B.; Kastner, Miriam; Egeberg, Per Kr.

    The compositions of pore and venting fluids at convergent margins differ from seawater values, reflecting mixing and diagenesis. Most significantly, the concentration of Cl-, assumed to be a conservative ion, differs from its seawater value. Chloride concentrations could be elevated by four processes, although two, the formation of gas hydrate and ion filtration by clay membranes, are insignificant in forming saline fluids at convergent margins. During the formation of gas hydrate, the resulting Cl--rich fluids, estimated to contain an average excess of ˜140 mM Cl- over seawater value, probably would be flushed from the sediment when the pore fluids vent to seawater. Ion filtration by clay membranes requires compaction pressures typical of >2 km burial depths. Even at these depths, the efficiency of ion filtration will be negligible because (1) fluids will flow through fractures, thereby bypassing clay membranes, (2) concentrations of clay minerals are diluted by other phases, and (3) during burial, smectite converts to illite, which has little capacity for ion filtration. A third process, mixing with subaerially evaporated seawater, elevates Cl- concentrations to 1043 mM in forearc basins along the Peru margin. Evaporation of seawater, however, will be important only in limited geographic regions that are characterized by enclosed basins, arid climates, and permeable sediments. At the New Hebrides and Izu-Bonin margins, Cl- concentrations are elevated to a maximum of 1241 mM. The process responsible for this increase is the alteration of volcanic ash to hydrous clay and zeolite minerals. Mass balance calculations, based on the decrease in δ18O values to -9.5‰ (SMOW), suggest that the Cl- concentrations could increase solely from the formation of smectite in a closed system. The diagenesis of volcanic ash also alters the concentrations of most dissolved species in addition to Cl-. Depending on the volume of this altered fluid, it could influence seawater

  17. Marginal longitudinal semiparametric regression via penalized splines

    KAUST Repository

    Al Kadiri, M.; Carroll, R.J.; Wand, M.P.

    2010-01-01

    We study the marginal longitudinal nonparametric regression problem and some of its semiparametric extensions. We point out that, while several elaborate proposals for efficient estimation have been proposed, a relative simple and straightforward one, based on penalized splines, has not. After describing our approach, we then explain how Gibbs sampling and the BUGS software can be used to achieve quick and effective implementation. Illustrations are provided for nonparametric regression and additive models.

  18. PENDIDIKAN ALTERNATIF UNTUK PEREMPUAN MARGINAL DI PEDESAAN

    Directory of Open Access Journals (Sweden)

    Ratnawati Tahir

    2011-11-01

    Full Text Available Abstract: Alternative Education for Marginalized Women in Rural Areas. The study aims to find alter­native forms of education for marginalized women, the process of forming study groups and gender based learning process that serves the center of the development of education, leadership and a source of economic empowerment. The study uses qualitative methods, involving a group of women who have attended an al­ternative education. Researchers and informants from community leaders. The results showed that the form of alternative education is a method of adult education or andragogy. Study groups consisted of basic literacy and functional literacy. The learning process begins with the sharing of learning, reflection on life experience and role play method. The result is 65% of participants have increased the ability of reading, writing and numeracy, and understanding of the issues of women who have confidence in the decision making of households and communities. Abstrak: Pendidikan Alternatif untuk Perempuan Marginal di Pedesaan. Penelitian ini bertujuan mengetahui bentuk pendidikan alternatif untuk perempuan marginal, proses pembentukan kelompok belajar, dan proses pembelajaran berperspektif gender yang berfungsi menjadi pusat pengembangan pendidikan, kepemimpinan, dan sumber penguatan ekonomi. Penelitian menggunakan metode kualitatif, mengambil satu kelompok perempuan yang telah mengikuti pendidikan alternatif. Informan terdiri atas tokoh masyarakat, seperti Kepala Desa, Ketua RT/RW, dan ibu rumah tangga. Hasil penelitian menunjukkan bahwa bentuk pembelajaran pendidikan alternatif adalah metode pendidikan orang dewasa atau andragogy. Pembentukan kelompok belajar terdiri atas; kelompok baca tulis dan keaksaraan fungsional. Proses pembe­lajaran dimulai dengan sharing pembelajaran, refleksi pengalaman hidup, dan metode role play. Hasilnya 65% peserta pembelajaran mengalami peningkatan kemampuan membaca, menulis, dan berhitung, serta pema

  19. Atlantic continental margin of the United States

    Science.gov (United States)

    Grow, John A.; Sheridan, Robert E.; Palmer, A.R.

    1982-01-01

    The objective of this Decade of North American Geology (D-NAG) volume will be to focus on the Mesozoic and Cenozoic evolution of the U.S. Atlantic continental margin, including the onshore coastal plain, related onshore Triassic-Jurassic rift grabens, and the offshore basins and platforms. Following multiple compressional tectonic episodes between Africa and North America during the Paleozoic Era that formed the Appalachian Mountains, the Mesozoic and Cenozoic Eras were dominated by tensional tectonic processes that separated Africa and North America. Extensional rifting during Triassic and Early Jurassic times resulted in numerous tensional grabens both onshore and offshore, which filled with nonmarine continental red beds, lacustrine deposits, and volcanic flows and debris. The final stage of this breakup between Africa and North America occurred beneath the present outer continental shelf and continental slope during Early or Middle Jurassic time when sea-floor spreading began to form new oceanic crust and lithosophere between the two continents as they drifted apart. Postrift subsidence of the marginal basins continued in response to cooling of the lithosphere and sedimentary loading.Geophysical surveys and oil-exploration drilling along the U.S. Atlantic continental margin during the past 5 years are beginning to answer many questions concerning its deep structure and stratigraphy and how it evolved during the rifting and early sea-floor-spreading stages of the separation of this region from Africa. Earlier geophysical studies of the U.S. continental margin used marine refraction and submarine gravity measurements. Single-channel seismic-reflection, marine magnetic, aeromagnetic, and continuous gravity measurements became available during the 1960s.

  20. Marginal microfiltration in amalgam restorations. Review

    OpenAIRE

    Lahoud Salem, Víctor

    2014-01-01

    The present articule is review references from phenomenon of microfiltration in restorations with amalgam and yours consecuents in changes of color in the interface tooth-restorations, margin deterioted , sensitivity dentinarea postoperate, caries secondary and pulp inflamation. Besides naming the mechanicals for to reduce microfiltration, and yours effects for use of sealers dentinaries representation for the varnish cavitys and adhesive systens Conclusive indicate wath the amalgam is the ma...

  1. Work culture and migrant women's welfare marginalization

    OpenAIRE

    Psimmenos, Iordanis

    2007-01-01

    Central to this paper is the relationship between work and welfare marginalization ofmigrant women domestic workers. Based upon the findings of a recent (2005-2007)research study on Albanian and Ukrainian domestic workers’ access to socialinsurance, medical and children’s care (i.e. nurseries, kindergartens), the paper claimsthat welfare barriers are constituted around lack of resources, discriminations as well asconditions and values at work.At the highest level of generality, paid domestic ...

  2. PREDICTIVE METHODS FOR STABILITY MARGIN IN BWR

    OpenAIRE

    MELARA SAN ROMÁN, JOSÉ

    2016-01-01

    [EN] Power and flow oscillations in a BWR are very undesirable. One of the major concerns is to ensure, during power oscillations, compliance with GDC 10 and 12. GDC 10 requires that the reactor core be designed with appropriate margin to assure that specified acceptable fuel design limits will not be exceeded during any condition of normal operation, including the effects of anticipated operational occurrences. GDC 12 requires assurance that power oscillations which can result in conditions ...

  3. Temporal variation in population size of European bird species: effects of latitude and marginality of distribution.

    Directory of Open Access Journals (Sweden)

    José J Cuervo

    Full Text Available In the Northern Hemisphere, global warming has been shown to affect animal populations in different ways, with southern populations in general suffering more from increased temperatures than northern populations of the same species. However, southern populations are also often marginal populations relative to the entire breeding range, and marginality may also have negative effects on populations. To disentangle the effects of latitude (possibly due to global warming and marginality on temporal variation in population size, we investigated European breeding bird species across a latitudinal gradient. Population size estimates were regressed on years, and from these regressions we obtained the slope (a proxy for population trend and the standard error of the estimate (SEE (a proxy for population fluctuations. The possible relationships between marginality or latitude on one hand and slopes or SEE on the other were tested among populations within species. Potentially confounding factors such as census method, sampling effort, density-dependence, habitat fragmentation and number of sampling years were controlled statistically. Population latitude was positively related to regression slopes independent of marginality, with more positive slopes (i.e., trends in northern than in southern populations. The degree of marginality was positively related to SEE independent of latitude, with marginal populations showing larger SEE (i.e., fluctuations than central ones. Regression slopes were also significantly related to our estimate of density-dependence and SEE was significantly affected by the census method. These results are consistent with a scenario in which southern and northern populations of European bird species are negatively affected by marginality, with southern populations benefitting less from global warming than northern populations, thus potentially making southern populations more vulnerable to extinction.

  4. On marginally resolved objects in optical interferometry

    Science.gov (United States)

    Lachaume, R.

    2003-03-01

    With the present and soon-to-be breakthrough of optical interferometry, countless objects shall be within reach of interferometers; yet, most of them are expected to remain only marginally resolved with hectometric baselines. In this paper, we tackle the problem of deriving the properties of a marginally resolved object from its optical visibilities. We show that they depend on the moments of flux distribution of the object: centre, mean angular size, asymmetry, and curtosis. We also point out that the visibility amplitude is a second-order phenomenon, whereas the phase is a combination of a first-order term, giving the location of the photocentre, and a third-order term, more difficult to detect than the visibility amplitude, giving an asymmetry coefficient of the object. We then demonstrate that optical visibilities are not a good model constraint while the object stays marginally resolved, unless observations are carried out at different wavelengths. Finally, we show an application of this formalism to circumstellar discs.

  5. Ocean Margins Programs, Phase I research summaries

    Energy Technology Data Exchange (ETDEWEB)

    Verity, P. [ed.

    1994-08-01

    During FY 1992, the DOE restructured its regional coastal-ocean programs into a new Ocean Margins Program (OMP), to: Quantify the ecological and biogeochemical processes and mechanisms that affect the cycling, flux, and storage of carbon and other biogenic elements at the land/ocean interface; Define ocean-margin sources and sinks in global biogeochemical cycles, and; Determine whether continental shelves are quantitatively significant in removing carbon dioxide from the atmosphere and isolating it via burial in sediments or export to the interior ocean. Currently, the DOE Ocean Margins Program supports more than 70 principal and co-principal investigators, spanning more than 30 academic institutions. Research funded by the OMP amounted to about $6.9M in FY 1994. This document is a collection of abstracts summarizing the component projects of Phase I of the OMP. This phase included both research and technology development, and comprised projects of both two and three years duration. The attached abstracts describe the goals, methods, measurement scales, strengths and limitations, and status of each project, and level of support. Keywords are provided to index the various projects. The names, addresses, affiliations, and major areas of expertise of the investigators are provided in appendices.

  6. Maximum Margin Clustering of Hyperspectral Data

    Science.gov (United States)

    Niazmardi, S.; Safari, A.; Homayouni, S.

    2013-09-01

    In recent decades, large margin methods such as Support Vector Machines (SVMs) are supposed to be the state-of-the-art of supervised learning methods for classification of hyperspectral data. However, the results of these algorithms mainly depend on the quality and quantity of available training data. To tackle down the problems associated with the training data, the researcher put effort into extending the capability of large margin algorithms for unsupervised learning. One of the recent proposed algorithms is Maximum Margin Clustering (MMC). The MMC is an unsupervised SVMs algorithm that simultaneously estimates both the labels and the hyperplane parameters. Nevertheless, the optimization of the MMC algorithm is a non-convex problem. Most of the existing MMC methods rely on the reformulating and the relaxing of the non-convex optimization problem as semi-definite programs (SDP), which are computationally very expensive and only can handle small data sets. Moreover, most of these algorithms are two-class classification, which cannot be used for classification of remotely sensed data. In this paper, a new MMC algorithm is used that solve the original non-convex problem using Alternative Optimization method. This algorithm is also extended for multi-class classification and its performance is evaluated. The results of the proposed algorithm show that the algorithm has acceptable results for hyperspectral data clustering.

  7. Pricing district heating by marginal cost

    International Nuclear Information System (INIS)

    Difs, Kristina; Trygg, Louise

    2009-01-01

    A vital measure for industries when redirecting the energy systems towards sustainability is conversion from electricity to district heating (DH). This conversion can be achieved for example, by replacing electrical heating with DH and compression cooling with heat-driven absorption cooling. Conversion to DH must, however, always be an economically attractive choice for an industry. In this paper the effects for industries and the local DH supplier are analysed when pricing DH by marginal cost in combination with industrial energy efficiency measures. Energy audits have shown that the analysed industries can reduce their annual electricity use by 30% and increase the use of DH by 56%. When marginal costs are applied as DH tariffs and the industrial energy efficiency measures are implemented, the industrial energy costs can be reduced by 17%. When implementing the industrial energy efficiency measures and also considering a utility investment in the local energy system, the local DH supplier has a potential to reduce the total energy system cost by 1.6 million EUR. Global carbon dioxide emissions can be reduced by 25,000 tonnes if the industrial energy efficiency measures are implemented and when coal-condensing power is assumed to be the marginal electricity source

  8. Marginalized Student Access to Technology Education

    Science.gov (United States)

    Kurtcu, Wanda M.

    The purpose of this paper is to investigate how a teacher can disrupt an established curriculum that continues the cycle of inequity of access to science, technology, engineering, and math (STEM) curriculum by students in alternative education. For this paper, I will focus on the technology components of the STEM curriculum. Technology in the United States, if not the world economy, is developing at a rapid pace. Many areas of day to day living, from applying for a job to checking one's bank account online, involve a component of science and technology. The 'gap' in technology education is emphasized between the 'haves and have-nots', which is delineated along socio-economic lines. Marginalized students in alternative education programs use this equipment for little else than remedial programs and credit recovery. This level of inequity further widens in alternative education programs and affects the achievement of marginalized students in credit recovery or alternative education classes instead of participation technology classes. For the purposes of this paper I focus on how can I decrease the inequity of student access to 21st century technology education in an alternative education program by addressing the established curriculum of the program and modifying structural barriers of marginalized student access to a technology focused curriculum.

  9. Diplopia due to Dacryops

    Directory of Open Access Journals (Sweden)

    Rahmi Duman

    2013-01-01

    Full Text Available Dacryops is a lacrimal ductal cyst. It is known that it can cause globe displacement, motility restriction, and proptosis because of the mass effect. Diplopia due to dacryops has not been reported previously. Here, we present a 57-year-old man with binocular horizontal diplopia that occurred during left direction gaze due to dacryops.

  10. Developing tools to identify marginal lands and assess their potential for bioenergy production

    Science.gov (United States)

    Galatsidas, Spyridon; Gounaris, Nikolaos; Dimitriadis, Elias; Rettenmaier, Nils; Schmidt, Tobias; Vlachaki, Despoina

    2017-04-01

    The term "marginal land" is currently intertwined in discussions about bioenergy although its definition is neither specific nor firm. The uncertainty arising from marginal land classification and quantification is one of the major constraining factors for its potential use. The clarification of political aims, i.e. "what should be supported?" is also an important constraining factor. Many approaches have been developed to identify marginal lands, based on various definitions according to the management goals. Concerns have been frequently raised regarding the impacts of marginal land use on environment, ecosystem services and sustainability. Current tools of soil quality and land potentials assessment fail to meet the needs of marginal land identification and exploitation for biomass production, due to the lack of comprehensive analysis of interrelated land functions and their quantitative evaluation. Land marginality is determined by dynamic characteristics in many cases and may therefore constitute a transitional state, which requires reassessment in due time. Also, marginal land should not be considered simply a dormant natural resource waiting to be used, since it may already provide multiple benefits and services to society relating to wildlife, biodiversity, carbon sequestration, etc. The consequences of cultivating such lands need to be fully addressed to present a balanced view of their sustainable potential for bioenergy. This framework is the basis for the development of the SEEMLA tools, which aim at supporting the identification, assessment, management of marginal lands in Europe and the decision-making for sustainable biomass production of them using appropriate bioenergy crops. The tools comprise two applications, a web-based one (independent of spatial data) and a GIS-based application (land regionalization on the basis of spatial data), which both incorporate: - Land resource characteristics, restricting the cultivation of agricultural crops but

  11. Perforated marginal ulcers after laparoscopic gastric bypass.

    Science.gov (United States)

    Felix, Edward L; Kettelle, John; Mobley, Elijah; Swartz, Daniel

    2008-10-01

    Perforated marginal ulcer (PMU) after laparoscopic Roux-en-Y gastric bypass (LRYGB) is a serious complication, but its incidence and etiology have rarely been investigated. Therefore, a retrospective review of all patients undergoing LRYGB at the authors' center was conducted to determine the incidence of PMU and whether any causative factors were present. A prospectively kept database of all patients at the authors' bariatric center was retrospectively reviewed. The complete records of patients with a PMU were examined individually for accuracy and analyzed for treatment, outcome, and possible underlying causes of the marginal perforation. Between April 1999 and August 2007, 1% of the patients (35/3,430) undergoing laparoscopic gastric bypass experienced one or more perforated marginal ulcers 3 to 70 months (median, 18 months) after LRYGB. The patients with and without perforation were not significantly different in terms of mean age (37 vs 41 years), weight (286 vs 287 lb), body mass index (BMI) (46 vs 47), or female gender (89% vs 83%). Of the patients with perforations, 2 (6%) were taking steroids, 10 (29%) were receiving nonsteroidal antiinflammatory drugs (NSAIDs) at the time of the perforation, 18 (51%) were actively smoking, and 6 of the smokers also were taking NSAIDs. Eleven of the patients (31%) who perforated did not have at least one of these possible risk factors, but 4 (36%) of the 11 patients in this group had been treated after bypass for a marginal ulcer. Only 7 (20%) of the 35 patients who had laparoscopic bypass, or 7 (0.2%) in the entire group of 3,430 patients, perforated without any warning. There were no deaths, but three patients reperforated. The incidence of a marginal ulcer perforating after LRYGB was significant (>1%) and appeared to be related to smoking or the use of NSAIDs or steroids. Because only 0.2% of all patients acutely perforated without some risk factor or warning, long-term ulcer prophylaxis or treatment may be necessary

  12. Convolution method and CTV-to-PTV margins for finite fractions and small systematic errors

    International Nuclear Information System (INIS)

    Gordon, J J; Siebers, J V

    2007-01-01

    The van Herk margin formula (VHMF) relies on the accuracy of the convolution method (CM) to determine clinical target volume (CTV) to planning target volume (PTV) margins. This work (1) evaluates the accuracy of the CM and VHMF as a function of the number of fractions N and other parameters, and (2) proposes an alternative margin algorithm which ensures target coverage for a wider range of parameter values. Dose coverage was evaluated for a spherical target with uniform margin, using the same simplified dose model and CTV coverage criterion as were used in development of the VHMF. Systematic and random setup errors were assumed to be normally distributed with standard deviations Σ and σ. For clinically relevant combinations of σ, Σ and N, margins were determined by requiring that 90% of treatment course simulations have a CTV minimum dose greater than or equal to the static PTV minimum dose. Simulation results were compared with the VHMF and the alternative margin algorithm. The CM and VHMF were found to be accurate for parameter values satisfying the approximate criterion: σ[1 - γN/25] 0.2, because they failed to account for the non-negligible dose variability associated with random setup errors. These criteria are applicable when σ ∼> σ P , where σ P = 0.32 cm is the standard deviation of the normal dose penumbra. (Qualitative behaviour of the CM and VHMF will remain the same, though the criteria might vary if σ P takes values other than 0.32 cm.) When σ P , dose variability due to random setup errors becomes negligible, and the CM and VHMF are valid regardless of the values of Σ and N. When σ ∼> σ P , consistent with the above criteria, it was found that the VHMF can underestimate margins for large σ, small Σ and small N. A potential consequence of this underestimate is that the CTV minimum dose can fall below its planned value in more than the prescribed 10% of treatments. The proposed alternative margin algorithm provides better margin

  13. Marginal costs and co-benefits of energy efficiency investments

    International Nuclear Information System (INIS)

    Jakob, Martin

    2006-01-01

    Key elements of present investment decision-making regarding energy efficiency of new buildings and the refurbishment of existing buildings are the marginal costs of energy efficiency measures and incomplete knowledge of investors and architects about pricing, co-benefits and new technologies. This paper reports on a recently completed empirical study for the Swiss residential sector. It empirically quantifies the marginal costs of energy efficiency investments (i.e. additional insulation, improved window systems, ventilation and heating systems and architectural concepts). For the private sector, first results on the economic valuation of co-benefits such as improved comfort of living, improved indoor air quality, better protection against external noise, etc. may amount to the same order of magnitude as the energy-related benefits are given. The cost-benefit analysis includes newly developed technologies that show large variations in prices due to pioneer market pricing, add-on of learning costs and risk components of the installers. Based on new empirical data on the present cost-situation and past techno-economic progress, the potential of future cost reduction was estimated applying the experience curve concept. The paper shows, for the first time, co-benefits and cost dynamics of energy efficiency investments, of which decision makers in the real estate sector, politics and administrations are scarcely aware

  14. Rectal cancer: involved circumferential resection margin - a root cause analysis.

    Science.gov (United States)

    Youssef, H; Collantes, E C; Rashid, S H; Wong, L S; Baragwanath, P

    2009-06-01

    An involved circumferential resection margin (CRM) following surgery for rectal cancer is the strongest predictor of local recurrence and may represent a failure of the multidisciplinary team (MDT) process. The study analyses the causes of positive CRM in patients undergoing elective surgery for rectal cancer with respect to the decision-making process of the MDT, preoperative rectal cancer staging and surgical technique. From March 2002 to September 2005, data were collected prospectively on all patients undergoing elective rectal cancer surgery with curative intent. The data on all patients identified with positive CRM were analysed. Of 158 patients (male:female = 2.2:1) who underwent potentially curative surgery, 16 (10%) patients had a positive CRM on postoperative histology. Four were due to failure of the pelvic magnetic resonance imaging (MRI) staging scans to predict an involved margin, two with an equivocal CRM on MRI did not have preoperative radiotherapy, one had an inaccurate assessment of the site of primary tumour and in one intra-operative difficulty was encountered. No failure of staging or surgery was identified in the remaining eight of the 16 patients. Abdominoperineal resection (APR) was associated with a 26% positive CRM, compared with 5% for anterior resection. No single consistent cause was found for a positive CRM. The current MDT process and/or surgical technique may be inadequate for low rectal tumours requiring APR.

  15. Occupational injuries due to violence.

    Science.gov (United States)

    Hales, T; Seligman, P J; Newman, S C; Timbrook, C L

    1988-06-01

    Each year in the United States, an estimated 800 to 1,400 people are murdered at work, and an unknown number of nonfatal injuries due to workplace violence occur. Based on Ohio's workers' compensation claims from 1983 through 1985, police officers, gasoline service station employees, employees of the real estate industry, and hotel/motel employees were found to be at the highest risk for occupational violent crime (OVC) injury and death. Grocery store employees, specifically those working in convenience food stores, and employees of the real estate industry had the most reported rapes. Four previously unidentified industries at increased risk of employee victimization were described. Identification of industries and occupations at high risk for crime victimization provides the opportunity to focus preventive strategies to promote employee safety and security in the workplace.

  16. Vaccine Safety

    Science.gov (United States)

    ... During Pregnancy Frequently Asked Questions about Vaccine Recalls Historical Vaccine Safety Concerns FAQs about GBS and Menactra ... CISA Resources for Healthcare Professionals Evaluation Current Studies Historical Background 2001-12 Publications Technical Reports Vaccine Safety ...

  17. SAFETY FIRST

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ensuring safety while peacefully utilizing nuclear energy is a top priority for China A fter a recent earthquake in Japan caused radioactive leaks at a nuclear power plant in Tokyo, the safety of nuclear energy has again aroused public attention.

  18. ITER safety

    International Nuclear Information System (INIS)

    Raeder, J.; Piet, S.; Buende, R.

    1991-01-01

    As part of the series of publications by the IAEA that summarize the results of the Conceptual Design Activities for the ITER project, this document describes the ITER safety analyses. It contains an assessment of normal operation effluents, accident scenarios, plasma chamber safety, tritium system safety, magnet system safety, external loss of coolant and coolant flow problems, and a waste management assessment, while it describes the implementation of the safety approach for ITER. The document ends with a list of major conclusions, a set of topical remarks on technical safety issues, and recommendations for the Engineering Design Activities, safety considerations for siting ITER, and recommendations with regard to the safety issues for the R and D for ITER. Refs, figs and tabs

  19. Water Safety

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Water Safety KidsHealth / For Parents / Water Safety What's in ... remains your best measure of protection. Making Kids Water Wise It's important to teach your kids proper ...

  20. Uncertainty Margin of Void Packet Determination for Ultrasonic Test in NPP

    International Nuclear Information System (INIS)

    Lee, Seungchan; Sung, Jejung; Lee, Jongchan; Kim, Jonguk

    2014-01-01

    In this study, the uncertainty of the void packet determination is estimated and the conservatism is reviewed by comparing with realistic uncertainty of Heckle's uncertainty. The methodology of ISO GUM is fully applied to calculate uncertainty, combined uncertainty and effective degree of freedom. Here some results are achieved as below: Combined uncertainty(UT) : 4.98%, Combined uncertainty(Heckle) : 1.44%, Degree of freedom: 5 ∼ 15, Effective degree of freedom(UT): 24.11, Effective degree of freedom(Heckle): 28.54, K value of t-distribution(UT): 2.042, K value of t-distribution(Heckle): 2.04, The uncertainty of this study using UT is enough in the case of achieving conservatism when the void packet determination of the safety related system is determined. As result of this study, UT uncertainty is more conservative than the Heckle's realistic uncertainty. From these results, it is shown that UT method has the great safety margin in determining the void packet. In comparing UT uncertainty with realistic uncertainty, this study (UT) has the conservatism of more than 3.4 times. UT method is good method to determine the void packet of ECCS pipe and to achieve the safety margin. In a safety related system, a void packet determination is issued by US NRC through the Generic Letter 2008-01. In case of the safety function, ECCS, CSS, and RHR systems are affected by the void packet. The related study has been being carried out by KHNP since 2012. In this study, the void packet determination using a ultra sonic test method has been carried out in some sites. This paper shows the uncertainty of the method using the ultra sonic test. The key parameters are introduced and estimated. Specially, the measurement conservatism for NPP is introduced to show the uncertainty margin

  1. Uncertainty Margin of Void Packet Determination for Ultrasonic Test in NPP

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seungchan; Sung, Jejung [Korea Hydro Nuclear Power Electricity Co., Daejeon (Korea, Republic of); Lee, Jongchan; Kim, Jonguk [FNC Technology Co., LTD., Yongin (Korea, Republic of)

    2014-05-15

    In this study, the uncertainty of the void packet determination is estimated and the conservatism is reviewed by comparing with realistic uncertainty of Heckle's uncertainty. The methodology of ISO GUM is fully applied to calculate uncertainty, combined uncertainty and effective degree of freedom. Here some results are achieved as below: Combined uncertainty(UT) : 4.98%, Combined uncertainty(Heckle) : 1.44%, Degree of freedom: 5 ∼ 15, Effective degree of freedom(UT): 24.11, Effective degree of freedom(Heckle): 28.54, K value of t-distribution(UT): 2.042, K value of t-distribution(Heckle): 2.04, The uncertainty of this study using UT is enough in the case of achieving conservatism when the void packet determination of the safety related system is determined. As result of this study, UT uncertainty is more conservative than the Heckle's realistic uncertainty. From these results, it is shown that UT method has the great safety margin in determining the void packet. In comparing UT uncertainty with realistic uncertainty, this study (UT) has the conservatism of more than 3.4 times. UT method is good method to determine the void packet of ECCS pipe and to achieve the safety margin. In a safety related system, a void packet determination is issued by US NRC through the Generic Letter 2008-01. In case of the safety function, ECCS, CSS, and RHR systems are affected by the void packet. The related study has been being carried out by KHNP since 2012. In this study, the void packet determination using a ultra sonic test method has been carried out in some sites. This paper shows the uncertainty of the method using the ultra sonic test. The key parameters are introduced and estimated. Specially, the measurement conservatism for NPP is introduced to show the uncertainty margin.

  2. Enhancing the diversity of breeding invertebrates within field margins of intensively managed grassland: Effects of alternative management practices.

    Science.gov (United States)

    Fritch, Rochelle A; Sheridan, Helen; Finn, John A; McCormack, Stephen; Ó hUallacháin, Daire

    2017-11-01

    Severe declines in biodiversity have been well documented for many taxonomic groups due to intensification of agricultural practices. Establishment and appropriate management of arable field margins can improve the diversity and abundance of invertebrate groups; however, there is much less research on field margins within grassland systems. Three grassland field margin treatments (fencing off the existing vegetation "fenced"; fencing with rotavation and natural regeneration "rotavated" and; fencing with rotavation and seeding "seeded") were compared to a grazed control in the adjacent intensively managed pasture. Invertebrates were sampled using emergence traps to investigate species breeding and overwintering within the margins. Using a manipulation experiment, we tested whether the removal of grazing pressure and nutrient inputs would increase the abundance and richness of breeding invertebrates within grassland field margins. We also tested whether field margin establishment treatments, with their different vegetation communities, would change the abundance and richness of breeding invertebrates in the field margins. Exclusion of grazing and nutrient inputs led to increased abundance and richness in nearly all invertebrate groups that we sampled. However, there were more complex effects of field margin establishment treatment on the abundance and richness of invertebrate taxa. Each of the three establishment treatments supported a distinct invertebrate community. The removal of grazing from grassland field margins provided a greater range of overwintering/breeding habitat for invertebrates. We demonstrate the capacity of field margin establishment to increase the abundance and richness in nearly all invertebrate groups in study plots that were located on previously more depauperate areas of intensively managed grassland. These results from grassland field margins provide evidence to support practical actions that can inform Greening (Pillar 1) and agri

  3. Optimization of safety equipment outages improves safety

    International Nuclear Information System (INIS)

    Cepin, Marko

    2002-01-01

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

  4. Food safety

    Science.gov (United States)

    ... safety URL of this page: //medlineplus.gov/ency/article/002434.htm Food safety To use the sharing features on this page, please enable JavaScript. Food safety refers to the conditions and practices that preserve the quality of food. These practices prevent contamination and foodborne ...

  5. Panhypopituitarism Due to Hemochromatosis

    OpenAIRE

    Mesut Özkaya; Kadir Gis; Ali Çetinkaya

    2013-01-01

    Hemochromatosis is an iron storage disease. Panhypopituitarism is a clinical condition in which the anterior pituitary hormones are deficient. Herein, we report a rare case of panhypopituitarism due to hemochromatosis. Turk Jem 2013; 17: 125-6

  6. Complementary safety assessment in the light of the Fukushima accident - Laue Langevin Institute

    International Nuclear Information System (INIS)

    Desbriere; Caillot; Bidet

    2012-01-01

    This CSA (Complementary Safety Assessment) analyses the robustness of the Grenoble High Flux reactor to extreme situations such as those that led to the Fukushima accident and proposes a series of improvements. Robustness is the ability for the facility to withstand events beyond the level for which the facility was designed. Robustness is linked to safety margins but also to the situations leading to a sudden deterioration of the accident sequence (cliff edge effect). Safety is not only a matter of design or of engineered systems, it is also a matter of organization. So issues like crisis organization and work organization via subcontracting are also taken into consideration. This report is divided into 9 main chapters: 1) main features of the high flux reactor, 2) macroscopic study of safety, identification of structures and equipment essential to safety, 3) earthquake risk, 4) flood risk, 5) risks due to other extreme natural disasters, 6) the loss of electrical power supplies and of cooling systems, 7) management of severe accidents, 8) subcontracting policy, 9) synthesis and improvements. This study confirms the robustness of the facility and a series of improvements and modifications is proposed to face very unlikely situations (especially plurality of failures) that were not taken into account in baseline safety studies. (A.C.)

  7. Deference and Due Process

    OpenAIRE

    Vermeule, Cornelius Adrian

    2015-01-01

    In the textbooks, procedural due process is a strictly judicial enterprise; although substantive entitlements are created by legislative and executive action, it is for courts to decide independently what process the Constitution requires. The notion that procedural due process might be committed primarily to the discretion of the agencies themselves is almost entirely absent from the academic literature. The facts on the ground are very different. Thanks to converging strands of caselaw ...

  8. Margination of Stiffened Red Blood Cells Regulated By Vessel Geometry.

    Science.gov (United States)

    Chen, Yuanyuan; Li, Donghai; Li, Yongjian; Wan, Jiandi; Li, Jiang; Chen, Haosheng

    2017-11-10

    Margination of stiffened red blood cells has been implicated in many vascular diseases. Here, we report the margination of stiffened RBCs in vivo, and reveal the crucial role of the vessel geometry in the margination by calculations when the blood is seen as viscoelastic fluid. The vessel-geometry-regulated margination is then confirmed by in vitro experiments in microfluidic devices, and it establishes new insights to cell sorting technology and artificial blood vessel fabrication.

  9. Marginal and Interaction Effects in Ordered Response Models

    OpenAIRE

    Debdulal Mallick

    2009-01-01

    In discrete choice models the marginal effect of a variable of interest that is interacted with another variable differs from the marginal effect of a variable that is not interacted with any variable. The magnitude of the interaction effect is also not equal to the marginal effect of the interaction term. I present consistent estimators of both marginal and interaction effects in ordered response models. This procedure is general and can easily be extended to other discrete choice models. I ...

  10. Nuclear safety in perspective

    International Nuclear Information System (INIS)

    Andersson, K.; Sjoeberg, B.M.D.; Lauridsen, K.; Wahlstroem, B.

    2002-06-01

    The aim of the NKS/SOS-1 project has been to enhance common understanding about requirements for nuclear safety by finding improved means of communicating on the subject in society. The project, which has been built around a number of seminars, was supported by limited research in three sub-projects: 1) Risk assessment, 2) Safety analysis, and 3) Strategies for safety management. The report describes an industry in change due to societal factors. The concepts of risk and safety, safety management and systems for regulatory oversight are described in the nuclear area and also, to widen the perspective, for other industrial areas. Transparency and public participation are described as key elements in good risk communication, and case studies are given. Environmental Impact Assessment and Strategic Environmental Assessment are described as important overall processes within which risk communication can take place. Safety culture, safety indicators and quality systems are important concepts in the nuclear safety area are very useful, but also offer important challenges for the future. They have been subject to special attention in the project. (au)

  11. Safety at work due to staff qualification and selection

    International Nuclear Information System (INIS)

    Brandt, W.

    1980-01-01

    An outline of basic requirements enabling the selection of employees for responsible staff in nuclear power stations. Illustrated further by the example of a model development from skilled worker to head of shift. A short reference will be made to the maintenance of high standards of training. (orig.) [de

  12. Safety assessment and verification for nuclear power plants. Safety guide

    International Nuclear Information System (INIS)

    2004-01-01

    This Safety Guide was prepared under the IAEA programme for safety standards for nuclear power plants. The present publication is a revision of the IAEA Safety Guide on Management of Nuclear Power Plants for Safe Operation issued in 1984. It supplements Section 2 of the Safety Requirements publication on Safety of Nuclear Power Plants: Operation. Nuclear power technology is different from the customary technology of power generation from fossil fuel and by hydroelectric means. One major difference between the management of nuclear power plants and that of conventional generating plants is the emphasis that should be placed on nuclear safety, quality assurance, the management of radioactive waste and radiological protection, and the accompanying national regulatory requirements. This Safety Guide highlights the important elements of effective management in relation to these aspects of safety. The attention to be paid to safety requires that the management recognize that personnel involved in the nuclear power programme should understand, respond effectively to, and continuously search for ways to enhance safety in the light of any additional requirements socially and legally demanded of nuclear energy. This will help to ensure that safety policies that result in the safe operation of nuclear power plants are implemented and that margins of safety are always maintained. The structure of the organization, management standards and administrative controls should be such that there is a high degree of assurance that safety policies and decisions are implemented, safety is continuously enhanced and a strong safety culture is promoted and supported. The objective of this publication is to guide Member States in setting up an operating organization which facilitates the safe operation of nuclear power plants to a high level internationally. The second objective is to provide guidance on the most important organizational elements in order to contribute to a strong safety

  13. Safety assessment and verification for nuclear power plants. Safety guide

    International Nuclear Information System (INIS)

    2005-01-01

    This Safety Guide was prepared under the IAEA programme for safety standards for nuclear power plants. The present publication is a revision of the IAEA Safety Guide on Management of Nuclear Power Plants for Safe Operation issued in 1984. It supplements Section 2 of the Safety Requirements publication on Safety of Nuclear Power Plants: Operation. Nuclear power technology is different from the customary technology of power generation from fossil fuel and by hydroelectric means. One major difference between the management of nuclear power plants and that of conventional generating plants is the emphasis that should be placed on nuclear safety, quality assurance, the management of radioactive waste and radiological protection, and the accompanying national regulatory requirements. This Safety Guide highlights the important elements of effective management in relation to these aspects of safety. The attention to be paid to safety requires that the management recognize that personnel involved in the nuclear power programme should understand, respond effectively to, and continuously search for ways to enhance safety in the light of any additional requirements socially and legally demanded of nuclear energy. This will help to ensure that safety policies that result in the safe operation of nuclear power plants are implemented and that margins of safety are always maintained. The structure of the organization, management standards and administrative controls should be such that there is a high degree of assurance that safety policies and decisions are implemented, safety is continuously enhanced and a strong safety culture is promoted and supported. The objective of this publication is to guide Member States in setting up an operating organization which facilitates the safe operation of nuclear power plants to a high level internationally. The second objective is to provide guidance on the most important organizational elements in order to contribute to a strong safety

  14. Safety handbook

    International Nuclear Information System (INIS)

    1990-01-01

    The purpose of the Australian Nuclear Science and Technology Organization's Safety Handbook is to outline simply the fundamental procedures and safety precautions which provide an appropriate framework for safe working with any potential hazards, such as fire and explosion, welding, cutting, brazing and soldering, compressed gases, cryogenic liquids, chemicals, ionizing radiations, non-ionising radiations, sound and vibration, as well as safety in the office. It also specifies the organisation for safety at the Lucas Heights Research Laboratories and the responsibilities of individuals and committees. It also defines the procedures for the scrutiny and review of all operations and the resultant setting of safety rules for them. ills

  15. Semisupervised kernel marginal Fisher analysis for face recognition.

    Science.gov (United States)

    Wang, Ziqiang; Sun, Xia; Sun, Lijun; Huang, Yuchun

    2013-01-01

    Dimensionality reduction is a key problem in face recognition due to the high-dimensionality of face image. To effectively cope with this problem, a novel dimensionality reduction algorithm called semisupervised kernel marginal Fisher analysis (SKMFA) for face recognition is proposed in this paper. SKMFA can make use of both labelled and unlabeled samples to learn the projection matrix for nonlinear dimensionality reduction. Meanwhile, it can successfully avoid the singularity problem by not calculating the matrix inverse. In addition, in order to make the nonlinear structure captured by the data-dependent kernel consistent with the intrinsic manifold structure, a manifold adaptive nonparameter kernel is incorporated into the learning process of SKMFA. Experimental results on three face image databases demonstrate the effectiveness of our proposed algorithm.

  16. Climate change and its marginalizing effect on agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Mestre-Sanchis, Fernando [Agriculture and Food Department, University of La Rioja (Spain); Feijoo-Bello, Maria Luisa [Economics Department, University of Zaragoza (Spain)

    2009-01-15

    The agriculture of some areas considered marginal in the EU agricultural context is being questioned due to its low productivity and growing dependence on economic aid programs Common Agricultural Policy (CAP). This study shows that climate change increases these areas marginalisation of since worsens crop growth conditions. The influence of climate change on the agricultural sector is analyzed using the Multicriteria Decision Paradigm with information provided by the Erosion-Productivity Impact Calculator (EPIC) and a General Circulation Model (GCM) as inputs for multicriteria mathematical programming models. The results obtained show climate change effects on the crop portfolio. Further results suggest that climate change effects are not only economics and environmental, reducing the suitable area for crops, but also social as it causes loss of jobs in the agricultural sector. (author)

  17. [Adolescense pregnancy in a marginalized rural community in Mexico].

    Science.gov (United States)

    Jiménez-González, Alberto; Granados-Cosme, José Arturo; Rosales-Flores, Roselia Arminda

    2017-01-01

    To identify objective and subjective conditions in the lives of pregnant teens within a highly-marginalized community in the state of Puebla, Mexico. Objective and subjective conditions of pregnant teens were evaluated through a mixed methodology (surveys, observation guides and a structured interview guide). The main family characteristic is the absence of a father due to migration, no desire to study or work and the new meaning of pregnancy: the initial social stigma for engaging in a sexual activity and then, the stigma for being a young mother. Objective conditions show family disintegration, lack of access to education at the community, high school and college level as well as unemployment as processes linked to teen pregnancy; thus, making it practically impossible to develop life goals. Subjective conditions center around the reproduction of gender stereotypes related to maternity.

  18. Principals' Perceived Supervisory Behaviors Regarding Marginal Teachers in Two States

    Science.gov (United States)

    Range, Bret; Hewitt, Paul; Young, Suzie

    2014-01-01

    This descriptive study used an online survey to determine how principals in two states viewed the supervision of marginal teachers. Principals ranked their own evaluation of the teacher as the most important factor when identifying marginal teachers and relied on informal methods to diagnose marginal teaching. Female principals rated a majority of…

  19. Product Safety Culture: A New Variant of Safety Culture?

    International Nuclear Information System (INIS)

    Suhanyiova, L.; Flin, R.; Irwin, A.

    2016-01-01

    Product safety culture is a new research area which concerns user safety rather than worker or process safety. The concept appears to have emerged after the investigation into the Nimrod aircraft accident (Haddon-Cave, 2009) which echoed aspects of NASA’s Challenger and Columbia crashes. In these cases, through a blend of human and organizational failures, the culture deteriorated to the extent of damaging product integrity, resulting in user fatalities. Haddon-Cave noted that it was due to a failure in leadership and organizational safety culture that accidents such as the Nimrod happened, where the aircraft exploded due to several serious technical failures, preceded by deficiencies in the safety case. Now some organizations are starting to measure product safety culture. This is important in day-to-day life as well, where a product failure as a result of poor organizational safety culture, can cause user harm or death, as in the case of Takata airbags scandal in 2015. Eight people have lost their lives and many were injured. According to investigation reports this was due to the company’s safety malpractices of fixing faulty airbags and proceeding to install them in vehicles, as well as secretly conducting tests to assess the integrity of their product and then deleting the data and denying safety issues as a result of the company’s cost-cutting policies. As such, organizational culture, specifically the applications of safety culture, can have far-reaching consequences beyond the workplace of an organization.

  20. Reactivation of precambrian faults on the southwestern continental margin of India: Evidence from gravity anomalies

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, V.; Ramana, M.V.; Rao, D.G.

    con- fi~ration of the western continental margin, with various structural styles, has been considered as a single unit, even though there exists a difference of opinion about the origin and evolution of the Chagos-Laccadive Ridge complex...’tVATION OF PRECAMBRIAN FAULTS ON THE SW CON~~E~AL MARGIN OF INDIA 337 shelf break due to the steep topographic relief of shelf. Furthermore, the gradients might have played a dominant role in shaping the bathymetry when the block movement took place along the pre...

  1. Segmentation of the eastern North Greenland oblique-shear margin – regional plate tectonic implications

    DEFF Research Database (Denmark)

    Andreasen, Arne Døssing; Stemmerik, Lars; Dahl-Jensen, T.

    2010-01-01

    a highly complex, Paleozoic–early Cenozoic pre-opening setting. However, due to extreme ice conditions, very little is known about the offshore areas seawards of – and between – the peninsulas. Consequently, prevailing structural-tectonic models of the margin tend to be significantly oversimplified...... anticipated. In particular, we interpret strong margin segmentation along N/NE-striking fault structures. The structures are likely to have formed by Late Mesozoic–early Cenozoic strike-slip tectonics and have continued to be active during the late Cenozoic. A more than 8 km deep sedimentary basin...

  2. Quantifying motion for pancreatic radiotherapy margin calculation

    International Nuclear Information System (INIS)

    Whitfield, Gillian; Jain, Pooja; Green, Melanie; Watkins, Gillian; Henry, Ann; Stratford, Julie; Amer, Ali; Marchant, Thomas; Moore, Christopher; Price, Patricia

    2012-01-01

    Background and purpose: Pancreatic radiotherapy (RT) is limited by uncertain target motion. We quantified 3D patient/organ motion during pancreatic RT and calculated required treatment margins. Materials and methods: Cone-beam computed tomography (CBCT) and orthogonal fluoroscopy images were acquired post-RT delivery from 13 patients with locally advanced pancreatic cancer. Bony setup errors were calculated from CBCT. Inter- and intra-fraction fiducial (clip/seed/stent) motion was determined from CBCT projections and orthogonal fluoroscopy. Results: Using an off-line CBCT correction protocol, systematic (random) setup errors were 2.4 (3.2), 2.0 (1.7) and 3.2 (3.6) mm laterally (left–right), vertically (anterior–posterior) and longitudinally (cranio-caudal), respectively. Fiducial motion varied substantially. Random inter-fractional changes in mean fiducial position were 2.0, 1.6 and 2.6 mm; 95% of intra-fractional peak-to-peak fiducial motion was up to 6.7, 10.1 and 20.6 mm, respectively. Calculated clinical to planning target volume (CTV–PTV) margins were 1.4 cm laterally, 1.4 cm vertically and 3.0 cm longitudinally for 3D conformal RT, reduced to 0.9, 1.0 and 1.8 cm, respectively, if using 4D planning and online setup correction. Conclusions: Commonly used CTV–PTV margins may inadequately account for target motion during pancreatic RT. Our results indicate better immobilisation, individualised allowance for respiratory motion, online setup error correction and 4D planning would improve targeting.

  3. Safety design

    International Nuclear Information System (INIS)

    Kunitomi, Kazuhiko; Shiozawa, Shusaku

    2004-01-01

    JAERI established the safety design philosophy of the HTTR based on that of current reactors such as LWR in Japan, considering inherent safety features of the HTTR. The strategy of defense in depth was implemented so that the safety engineering functions such as control of reactivity, removal of residual heat and confinement of fission products shall be well performed to ensure safety. However, unlike the LWR, the inherent design features of the high-temperature gas-cooled reactor (HTGR) enables the HTTR meet stringent regulatory criteria without much dependence on active safety systems. On the other hand, the safety in an accident typical to the HTGR such as the depressurization accident initiated by a primary pipe rupture shall be ensured. The safety design philosophy of the HTTR considers these unique features appropriately and is expected to be the basis for future Japanese HTGRs. This paper describes the safety design philosophy and safety evaluation procedure of the HTTR especially focusing on unique considerations to the HTTR. Also, experiences obtained from an HTTR safety review and R and D needs for establishing the safety philosophy for the future HTGRs are reported

  4. Nuclear Safety

    International Nuclear Information System (INIS)

    1978-09-01

    In this short paper it has only been possible to deal in a rather general way with the standards of safety used in the UK nuclear industry. The record of the industry extending over at least twenty years is impressive and, indeed, unique. No other industry has been so painstaking in protection of its workers and in its avoidance of damage to the environment. Headings are: introduction; how a nuclear power station works; radiation and its effects (including reference to ICRP, the UK National Radiological Protection Board, and safety standards); typical radiation doses (natural radiation, therapy, nuclear power programme and other sources); safety of nuclear reactors - design; key questions (matters of concern which arise in the public mind); safety of operators; safety of people in the vicinity of a nuclear power station; safety of the general public; safety bodies. (U.K.)

  5. Injury due to thorotrast

    International Nuclear Information System (INIS)

    Mori, Takesaburo

    1976-01-01

    A synthetic study was performed on some of those to whom Thorotrast had been injected, in Japan. In the epidemiological study of 147 war woundeds to whom Thorotrast had been injected, it was noted that the Thorotrast injection increased the mortality rate and the incidences of malignant hepatic tumor, liver cirrhosis, and hematological diseases. Clinical study of 44 of them showed that the Thorotrast injection resulted in liver and hematopoietic hypofunctions. Analysis of the dissection of the injected area in 118 cases showed malignant hepatic tumor in 63.5%, liver cirrhosis in 14.4% and hematological diseases in 10.2%. The total of the three types of disease was 88.1%. Histological classification showed that of the malignant hepatic tumors due to Thorotrast, hepatobiliary cancer and hemangioendothelioma of the liver were frequent. By the comparison of the absorbed dose in the liver of the malignant hepatic tumors due to Thorotrast with that of the cancers developed in animal experiments, it was noted that the carcinogenic dose was a mean of 2,000 - 3,000 rad by accumulated dose. It was elucidated that carcinogenesis and fibrination were primary in injury due to Thorotrast, i.e., late injury due to Thorotrast, and that the increase in the accumulated dose in rogans and the increase of the local dose due to the gigantic growth of Thorotrast granules in organs greatly influenced carninogenesis and fibrination. (Chiba, N.)

  6. Deep Structures of The Angola Margin

    Science.gov (United States)

    Moulin, M.; Contrucci, I.; Olivet, J.-L.; Aslanian, D.; Géli, L.; Sibuet, J.-C.

    1 Ifremer Centre de Brest, DRO/Géosciences Marines, B.P. 70, 29280 Plouzané cedex (France) mmoulin@ifremer.fr/Fax : 33 2 98 22 45 49 2 Université de Bretagne Occidentale, Institut Universitaire Europeen de la Mer, Place Nicolas Copernic, 29280 Plouzane (France) 3 Total Fina Elf, DGEP/GSR/PN -GEOLOGIE, 2,place de la Coupole-La Defense 6, 92078 Paris la Defense Cedex Deep reflection and refraction seismic data were collected in April 2000 on the West African margin, offshore Angola, within the framework of the Zaiango Joint Project, conducted by Ifremer and Total Fina Elf Production. Vertical multichannel reflection seismic data generated by a « single-bubble » air gun array array (Avedik et al., 1993) were recorded on a 4.5 km long, digital streamer, while refraction and wide angle reflection seismic data were acquired on OBSs (Ocean Bottom Seismometers). Despite the complexity of the margin (5 s TWT of sediment, salt tectonics), the combination of seismic reflection and refraction methods results in an image and a velocity model of the ground structures below the Aptian salt layer. Three large seismic units appear in the reflection seismic section from the deep part on the margin under the base of salt. The upper seismic unit is layered with reflectors parallel to the base of the salt ; it represents unstructured sediments, filling a basin. The middle unit is seismically transparent. The lower unit is characterized by highly energetic reflectors. According to the OBS refraction data, these two units correspond to the continental crust and the base of the high energetic unit corresponds to the Moho. The margin appears to be divided in 3 domains, from east to west : i) a domain with an unthinned, 30 km thick, continental crust ; ii) a domain located between the hinge line and the foot of the continental slope, where the crust thins sharply, from 30 km to less than 7 km, this domain is underlain by an anormal layer with velocities comprising between 7,2 and 7

  7. The marginal cost of public funds

    DEFF Research Database (Denmark)

    Kleven, Henrik Jacobsen; Kreiner, Claus Thustrup

    2006-01-01

    This paper extends the theory and measurement of the marginal cost of public funds (MCF) to account for labor force participation responses. Our work is motivated by the emerging consensus in the empirical literature that extensive (participation) responses are more important than intensive (hours...... of work) responses. In the modelling of extensive responses, we argue that it is crucial to account for the presence of non-convexities created by fixed work costs. In a non-convex framework, tax and transfer reforms give rise to discrete participation responses generating first-order effects...

  8. Intacs for early pellucid marginal degeneration.

    Science.gov (United States)

    Kymionis, George D; Aslanides, Ioannis M; Siganos, Charalambos S; Pallikaris, Ioannis G

    2004-01-01

    A 42-year-old man had Intacs (Addition Technology Inc.) implantation for early pellucid marginal degeneration (PMD). Two Intacs segments (0.45 mm thickness) were inserted uneventfully in the fashion typically used for low myopia correction (nasal-temporal). Eleven months after the procedure, the uncorrected visual acuity was 20/200, compared with counting fingers preoperatively, while the best spectacle-corrected visual acuity improved to 20/25 from 20/50. Corneal topographic pattern also improved. Although the results are encouraging, concern still exists regarding the long-term effect of this approach for the management of patients with PMD.

  9. TENNESSEE WILLIAMS E O TEATRO MARGINAL GAY

    Directory of Open Access Journals (Sweden)

    Adriana Falqueto Lemos

    2014-06-01

    Full Text Available The work developed in this text aims to read the dramatist Tennnessee Williams in a play in two scenes “E Contar Tristes Histórias das Mortes das Bonecas” which was published in Brazil in the book “Mister Paradise e outras peças em um ato” (2011. The intention is to reflect upon one of his recurring themes, the marginalization. In order to perform the analysis, the theoretical support was grounded in “Literatura e Sociedade” by Antonio Candido (2006, concerning the participation of society and authorship in a piece of literature.

  10. TENNESSEE WILLIAMS E O TEATRO MARGINAL GAY

    Directory of Open Access Journals (Sweden)

    Adriana Falqueto Lemos

    2014-09-01

    Full Text Available The work developed in this text aims to read the dramatist Tennnessee Williams in a play in two scenes “E Contar Tristes Histórias das Mortes das Bonecas” which was published in Brazil in the book “Mister Paradise e outras peças em um ato” (2011. The intention is to reflect upon one of his recurring themes, the marginalization. In order to perform the analysis, the theoretical support was grounded in “Literatura e Sociedade” by Antonio Candido (2006, concerning the participation of society and authorship in a piece of literature.

  11. Absenteeism, efficiency wages, and marginal taxes

    OpenAIRE

    Dale-Olsen, Harald

    2013-01-01

    In this paper, I test the argument that increased taxes on earnings correspond to increased incentives to shirk, thus causing an increase in the rate of worker absenteeism. After fixed job effects are taken into account, panel register data on prime-age Norwegian males who work full-time show that a higher marginal net-of-earnings-tax rate reduces the rate of absenteeism. When the net-of-tax rate is increased by 1.0 percent, absenteeism decreases by 0.3−0.5 percent. Injury-related absences ar...

  12. Advances made in French safety studies on pressurized water reactors

    International Nuclear Information System (INIS)

    Pelce, J.

    1979-01-01

    The programme of French safety studies on reactors is supposed to be known in its main outlines. A few recent results, obtained in different fields are presented. They concern the safety margins evaluation, the contamination transfer and the effect of external aggressions

  13. Design trade-offs in view of safety considerations

    International Nuclear Information System (INIS)

    Saji, G.; Kishida, K.; Inoue, T.

    1978-01-01

    In view of resolving conflicting demands of cost, safety, flexibility of operation and design margins, safety design of various plant systems is discussed referring to their weight on construction costs. An influence of hypothetical core disruptive accident (HCDA) and loss of piping integrity (LOPI) on plant design and thus on construction materials is discussed, in optimising future commercial FBR plants. (author)

  14. Anaphylaxis due to caffeine

    OpenAIRE

    Sugiyama, Kumiya; Cho, Tatsurai; Tatewaki, Masamitsu; Onishi, Shogo; Yokoyama, Tatsuya; Yoshida, Naruo; Fujimatsu, Takayoshi; Hirata, Hirokuni; Fukuda, Takeshi; Fukushima, Yasutsugu

    2015-01-01

    We report a rare case of anaphylaxis due to caffeine intake. A 27-year-old woman suffered her first episode of anaphylaxis and a positive skin prick test suggested that the anaphylaxis was due to an IgE-mediated hypersensitivity reaction to caffeine. She was diagnosed with caffeine allergy and has not had an allergic reaction after avoiding foods and drinks containing caffeine. Although caffeine is known to have antiallergic effects, this case shows that caffeine can be an allergen and cause ...

  15. Public and Private Physical Affection Differences between Same-Sex and Different-Sex Couples: The Role of Perceived Marginalization

    OpenAIRE

    Amani El-Alayli; Erin Kent

    2011-01-01

    Despite its connection with relationship satisfaction, research on physical affection is scarce and fails to disentangle private and public displays of affection. It is important to examine both types if marginalized couples are less comfortable displaying affection publicly. The present study examined whether same-sex couples display less public (but not private) physical affection than different-sex couples due to stronger feelings of relationship marginalization. It also examined how publ...

  16. Relationship of safety culture and process safety

    International Nuclear Information System (INIS)

    Olive, Claire; O'Connor, T. Michael; Mannan, M. Sam

    2006-01-01

    Throughout history, humans have gathered in groups for social, religious, and industrial purposes. As the conglomeration of people interact, a set of underlying values, beliefs, and principles begins to develop that serve to guide behavior within the group. These 'guidelines' are commonly referred to as the group culture. Modern-day organizations, including corporations, have developed their own unique cultures derived from the diversity of the organizational interests and the background of the employees. Safety culture, a sub-set of organizational culture, has been a major focus in recent years. This is especially true in the chemical industry due to the series of preventable, safety-related disasters that occurred in the late seventies and eighties. Some of the most notable disasters, during this time period, occurred at Bhopal, Flixborough, and Seveso. However, current events, like the September 11th terrorist attacks and the disintegration of the Columbia shuttle, have caused an assessment of safety culture in a variety of other organizations

  17. A gene signature in histologically normal surgical margins is predictive of oral carcinoma recurrence

    International Nuclear Information System (INIS)

    Reis, Patricia P; Simpson, Colleen; Goldstein, David; Brown, Dale; Gilbert, Ralph; Gullane, Patrick; Irish, Jonathan; Jurisica, Igor; Kamel-Reid, Suzanne; Waldron, Levi; Perez-Ordonez, Bayardo; Pintilie, Melania; Galloni, Natalie Naranjo; Xuan, Yali; Cervigne, Nilva K; Warner, Giles C; Makitie, Antti A

    2011-01-01

    Oral Squamous Cell Carcinoma (OSCC) is a major cause of cancer death worldwide, which is mainly due to recurrence leading to treatment failure and patient death. Histological status of surgical margins is a currently available assessment for recurrence risk in OSCC; however histological status does not predict recurrence, even in patients with histologically negative margins. Therefore, molecular analysis of histologically normal resection margins and the corresponding OSCC may aid in identifying a gene signature predictive of recurrence. We used a meta-analysis of 199 samples (OSCCs and normal oral tissues) from five public microarray datasets, in addition to our microarray analysis of 96 OSCCs and histologically normal margins from 24 patients, to train a gene signature for recurrence. Validation was performed by quantitative real-time PCR using 136 samples from an independent cohort of 30 patients. We identified 138 significantly over-expressed genes (> 2-fold, false discovery rate of 0.01) in OSCC. By penalized likelihood Cox regression, we identified a 4-gene signature with prognostic value for recurrence in our training set. This signature comprised the invasion-related genes MMP1, COL4A1, P4HA2, and THBS2. Over-expression of this 4-gene signature in histologically normal margins was associated with recurrence in our training cohort (p = 0.0003, logrank test) and in our independent validation cohort (p = 0.04, HR = 6.8, logrank test). Gene expression alterations occur in histologically normal margins in OSCC. Over-expression of the 4-gene signature in histologically normal surgical margins was validated and highly predictive of recurrence in an independent patient cohort. Our findings may be applied to develop a molecular test, which would be clinically useful to help predict which patients are at a higher risk of local recurrence

  18. Targeting Bruton tyrosine kinase with ibrutinib in relapsed/refractory marginal zone lymphoma.

    Science.gov (United States)

    Noy, Ariela; de Vos, Sven; Thieblemont, Catherine; Martin, Peter; Flowers, Christopher R; Morschhauser, Franck; Collins, Graham P; Ma, Shuo; Coleman, Morton; Peles, Shachar; Smith, Stephen; Barrientos, Jacqueline C; Smith, Alina; Munneke, Brian; Dimery, Isaiah; Beaupre, Darrin M; Chen, Robert

    2017-04-20

    Marginal zone lymphoma (MZL) is a heterogeneous B-cell malignancy for which no standard treatment exists. MZL is frequently linked to chronic infection, which may induce B-cell receptor (BCR) signaling, resulting in aberrant B-cell survival and proliferation. We conducted a multicenter, open-label, phase 2 study to evaluate the efficacy and safety of ibrutinib in previously treated MZL. Patients with histologically confirmed MZL of all subtypes who received ≥1 prior therapy with an anti-CD20 antibody-containing regimen were treated with 560 mg ibrutinib orally once daily until progression or unacceptable toxicity. The primary end point was independent review committee-assessed overall response rate (ORR) by 2007 International Working Group criteria. Among 63 enrolled patients, median age was 66 years (range, 30-92). Median number of prior systemic therapies was 2 (range, 1-9), and 63% received ≥1 prior chemoimmunotherapy. In 60 evaluable patients, ORR was 48% (95% confidence interval [CI], 35-62). With median follow-up of 19.4 months, median duration of response was not reached (95% CI, 16.7 to not estimable), and median progression-free survival was 14.2 months (95% CI, 8.3 to not estimable). Grade ≥3 adverse events (AEs; >5%) included anemia, pneumonia, and fatigue. Serious AEs of any grade occurred in 44%, with grade 3-4 pneumonia being the most common (8%). Rates of discontinuation and dose reductions due to AEs were 17% and 10%, respectively. Single-agent ibrutinib induced durable responses with a favorable benefit-risk profile in patients with previously treated MZL, confirming the role of BCR signaling in this malignancy. As the only approved therapy, ibrutinib provides a treatment option without chemotherapy for MZL. This study is registered at www.clinicaltrials.gov as #NCT01980628. © 2017 by The American Society of Hematology.

  19. HISTOPATHOLOGY OF MARGINAL SUPERFICIAL PERIODONTIUM AT MENOPAUSE

    Directory of Open Access Journals (Sweden)

    A. Georgescu

    2012-03-01

    Full Text Available Premises: Sexual hormones may affect the general health condition of women, as early as puberty, continuing during pregnancy and also after menopause. Variations of the hormonal levels may cause different – either local or general – pathological modifications. Sexual hormones may also affect periodontal status, favourizing gingival inflammations and reducing periodontal resistance to the action of the bacterial plaque. Scope: Establishment of the correlations between the debut or the manifestation of menopause and the modifications produced in the superficial periodontium. Materials and method: Clinical and paraclinical investigations were performed on female patients with ages between 45 and 66 years, involving macroscopic, microscopic and radiological recording of the aspect of the superificial periodontium (gingiva. Results: Analysis of the histological sections evidenced atrophic and involutive modifications in the marginal superficial periodontium of female patients at menopause. Conclusions: Sexual hormones intervene in the histological equilibrium of the marginal superficial periodontium, influencing the periodontal health status, which explains the correlation between the subjective symptomatology specific to menopause and the histopatological aspect at epithelial level.

  20. Oral antioxidant therapy for marginal dry eye.

    Science.gov (United States)

    Blades, K J; Patel, S; Aidoo, K E

    2001-07-01

    To assess the efficacy of an orally administered antioxidant dietary supplement for managing marginal dry eye. A prospective, randomised, placebo controlled trial with cross-over. Eye Clinic, Department of Vision Sciences, Glasgow Caledonian University. Forty marginal dry eye sufferers composed of 30 females and 10 males (median age 53 y; range 38-69 y). Baseline assessments were made of tear volume sufficiency (thread test), tear quality (stability), ocular surface status (conjunctival impression cytology) and dry eye symptoms (questionnaire). Each subject was administered courses of active treatment, placebo and no treatment, in random order for 1 month each and results compared to baseline. Tear stability and ocular surface status were significantly improved following active treatment (Ptreatment (P>0.05). Absolute increase in tear stability correlated with absolute change in goblet cell population density. Tear volume was not improved following any treatment period and dry eye symptom responses were subject to placebo effect. Oral antioxidants improved both tear stability and conjunctival health, although it is not yet understood whether increased ocular surface health mediates increased tear stability or vice versa. This study was supported by a PhD scholarship funded by the Department of Vision Sciences, Glasgow Caledonian University, Scotland. Antioxidant supplements and placebos were kindly donated by Vitabiotics.